CR)Titanium Dioxide-Based Nanomaterials for Photocatalytic Fuel Generations

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纳米二氧化钛在能源和环境治理方面的应用

纳米二氧化钛在能源和环境治理方面的应用张娜娜;何又青;严尹涛;沈丹青【摘要】With the development of nanometer material technology, the material research field has made further progress. As a new nanomaterial, nanometer titanium dioxide has been widely used in the preparation of energy materials and environmental protection because of its strong photocatalytic effect, good thermal stability, reusable and other characteristics. The nanometer titanium dioxide in the management of water pollution, air pollution, soil restoration, and how to improve the application of solar cell conversion efficiency were introduced. The problems at present, the future development and the application prospect of the future were described.%随着纳米材料技术的发展, 使得材料研究领域又有了更进一步的飞跃.纳米二氧化钛作为一种新兴的纳米材料,因其具有光催化效果强、热稳定好、可重复使用等特性, 使其在能源材料的制备和环境保护等方面得到了广泛的应用.本文着重介绍纳米二氧化钛在水体污染、空气污染的治理, 土壤修复以及提高太阳能电池转化效率等方面的应用, 并对其在现阶段存在的问题和未来的发展及应用前景做出了展望.【期刊名称】《广州化工》【年(卷),期】2018(046)012【总页数】2页(P19-20)【关键词】二氧化钛(TiO2);光催化性能;纳米;应用【作者】张娜娜;何又青;严尹涛;沈丹青【作者单位】宿迁学院信息工程学院,江苏宿迁 223800;宿迁学院信息工程学院,江苏宿迁 223800;宿迁学院信息工程学院,江苏宿迁 223800;宿迁学院信息工程学院,江苏宿迁 223800【正文语种】中文【中图分类】O643.36现代工业化的迅猛发展，除了给人们带来的是经济的飞速发展和生活的安逸，同时还带来了环境方面的污染。

南京理工大学科技成果——钛合金人工关节头表面耐磨层的制备方法

南京理工大学科技成果——钛合金人工关节头表面
耐磨层的制备方法
成果简介：
磨损是人工关节无菌松动和晚期失效的主要因素，钛合金具有优异生物相容性和生物力学性能。

本研究针对其耐磨性差的问题，首次采用全方位两步离子注入的方法，在钛合金表面先高靶温（或高能量）注入N+，再高剂量注入O+，在钛合金表面制备出具有高结合强度、高承载能力的Ti-O—Ti-N梯度膜。

增强了钛合金表面硬度，改善了表面与关节滑液的润湿性，显著提高了关节摩擦副双方的耐磨性能。

技术指标：
改性后摩擦系数只是未改性的1/8，UHMWPE与两步离子注入钛合金摩擦时，耐磨性提高了40多倍，而且两步离子注入钛合金表面几乎观察不到磨痕。

项目水平：国内领先
成熟程度：小试
合作方式：合作开发、专利许可、技术转让、技术入股等。

纯钛表面立方介孔sio2薄膜诱导沉积碳磷灰石层

纯钛表面立方介孔SiO2薄膜诱导沉积碳磷灰石层引言：人工骨替代材料的研究和应用一直是医学领域的重要课题，其中钛合金是一种常用的人工骨替代材料。

但是，钛合金在人体内长期使用容易出现生物相容性问题，因此需要对其表面进行改性。

本文研究了纯钛表面立方介孔SiO2薄膜诱导沉积碳磷灰石层的方法，以提高钛合金的生物相容性和骨生长性能。

实验方法：1. 制备纯钛表面立方介孔SiO2薄膜将纯钛表面进行清洗和处理，然后在其表面沉积一层SiO2薄膜。

通过改变沉积时间和温度等条件，可以控制SiO2薄膜的孔径和厚度。

2. 沉积碳磷灰石层将制备好的纯钛表面立方介孔SiO2薄膜放入含有磷酸二氢钾和葡萄糖的人工体液中，然后加热反应。

在反应过程中，SiO2薄膜会诱导磷酸二氢钾和葡萄糖在其表面形成碳磷灰石层。

结果与分析：通过扫描电子显微镜和X射线衍射分析，发现沉积在纯钛表面立方介孔SiO2薄膜上的碳磷灰石层具有较好的结晶性和致密性。

同时，通过细胞培养实验，发现这种表面处理后的钛合金对细胞有较好的生物相容性和骨细胞的黏附和增殖能力。

结论：纯钛表面立方介孔SiO2薄膜诱导沉积碳磷灰石层是一种有效的改性方法，可以提高钛合金的生物相容性和骨生长性能。

这种方法具有简单、可控性强、成本低等优点，有望在人工骨替代材料的研究和应用中得到广泛应用。

结构图：纯钛表面立方介孔SiO2薄膜诱导沉积碳磷灰石层的结构图如下图所示：纯钛表面→ 立方介孔SiO2薄膜→ 碳磷灰石层参考文献：[1] Jia X, et al. Facile fabrication of bioactive coatings on titanium substrates using a biomimetic method. Colloids Surf B Biointerfaces, 2013, 102: 367-374.[2] Wang Y, et al. Fabrication of carbonated hydroxyapatite coatings ontitanium substrates by a biomimetic method. Mater Sci Eng C Mater Biol Appl, 2013, 33(2): 919-925.[3] Zhang X, et al. The effect of hierarchical micro/nano-topography on the biological properties of titanium implant surfaces. Mater Sci Eng C Mater Biol Appl, 2014, 42: 70-76.。

金属掺杂锐钛矿相TiO2的第一性原理计算

金属掺杂锐钛矿相TiO2的第一性原理计算金属掺杂锐钛矿相TiO2的第一性原理计算/王海东等?129?金属掺杂锐钛矿相TiO2的第一性原理计算王海东,万巍(中南大学无机材料研究所,长沙410083)摘要采用基于密度泛函理论的从头算平面波超软赝势方法,计算了纯锐钛矿相TiU2及5种不同金属掺杂Ti()2的晶格常数,能带结构,态密度与光吸收系数.结果表明,掺杂后能级的变化主要是过渡金属Co3d,Fe3d,Zr4d,Zr4p,V3p,V3d,W5d及W5p轨道的贡献.随着co,Fe,V掺杂浓度的增加,禁带宽度呈减小趋势;Zr掺杂对能带结构几乎不产生影响;W掺杂能级远离禁带,只对价带构成产生了影响.金属掺杂使禁带宽度变化或出现新杂质能级,导致了Ti()2吸收边沿红移或在可见光区域出现新的吸收峰;其中Co,Fe掺杂的吸收边沿明显红移,而w掺杂时在可见光区域出现较强的吸收峰.'关键词第一性原理锐钛矿相TiOz金属掺杂中图分类号:TN302;O411文献标识码:A StudyontheMetalDopedAnataseTiO2byFirstPrinciplesW ANGHaidong,WANWei(InstituteofInorganicMaterials,CentralSouthUniversity,Changsha410083) AbstractThelatticeconstant,bandstructure,densityofstatesandopticalpropertiesofpurean dCo,Fe,Zr,V,WdopingTi02werecalculatedusingthefirst-principleplane-waveultrasoftpseudopotent ialmethodsbasedonthe densityfunctionaltheorNTheresultsindicatethattheformationofimpuritylevelismainlyco ntributedbymixingwithCO3d,Fe3d,Zr4p,Zr4d,V3p,V3d,W5p,W5dorbita1ofthetransitionmeta1.Thebandg apdecreaseswithincreasingCo,ice,Vconcentration.ThereisnoimpuritylevelpresentinthebandstructureofZ rdopingTi02.Impu—ritylevelofWdopingTi02leavesawayfromthebandgap,onlycausestheconstitutionofvalen ceban&Thedoping withmetalliciconsisresponsibleforthechangesofbandgapornewappearanceofimpurityle vel,whichbringstheredshiftofTi02absorptionwavelengthortheappearanceofnewabsorptionpeakinthevisible 1ightregion.Thedo—pingofCo,FebringstheredshiftofTi02absorptionwavelengthobviouslyandW-dopingcaus esastrongabsorptionpeakinthevisiblelightregion.KeywordsFirst-principlecalculation,anatasetitaniumdioxide,metaldoped0引言作为光催化环境净化材料,Ti0因具有无毒,成本低,稳定性好等诸多优点而成为最具研发潜力的光催化剂.但由于TiO是宽禁带半导体氧化物,使其对太阳能的利用受到了限制.因此,如何通过改性手段提高其光谱响应范围是TiO光催化性能推广应用的关键.对TiOz的改性研究表明,金属离子掺杂改性是有效的方法之一理想的掺杂离子应在材料内形成合适的施主或受主能级,且这些能级位于距离导带或价带较理想的位置,既可以俘获载流子促进光生载流子的分离,又能快速释放载流子以避免成为载流子失活中心[1].在已开展的金属离子掺杂TiO光催化活性的实验研究中,Choi等采用Sol—gel法将与Ti半径接近的21种金属离子掺入到TiO中,结果表明,掺杂Fe",Mo",Ru什,Os抖,Re汁,V",Rh3均可明显提高TiO的氧化还原能力,而Li,M,Al",Ga什等S区及P区离子掺杂则降低了Ti0.的光催化活性.相对于实验研究,模拟计算技术具有可以克服实验中人为因素的影响,更易于深入分析离子掺杂改性机理的特点.从2O世纪9O年代开始应用第一性原理对Ti02纳米材料进行计算模拟的研究工作已逐渐展开r3].曹红红等_4]使用全电势线性缀加平面波法,对锐钛矿相TiO做了较系统的计算,优化后所得结果与实验值符合得很好.Umebayashi等]利用基于密度泛函理论的全电势线性缀加平面波法计算了3d过渡金属掺杂锐钛矿相TiO.的电子结构,结果表明掺杂物的t.态在禁带或价带中产生了一个杂质能级,并且随着掺杂原子序数的增大,杂质能级向低能级方向移动.为进一步系统地研究金属掺杂对锐钛矿相TiO光催化性能的影响机理,采用基于密度泛函理论的从头算平面波超软赝势方法,计算了纯锐钛矿相Ti()2及5种不同金属(Co,*教育部博士点基金(20100162110062)王海东:1963年生,博士,教授Tel:0731—8836963E-mail:***************】30?材料导报B:研究篇2O11年7月(下)第25卷第7期Fe,Zr,V,w)在多浓度掺杂下TiO.的晶格常数,能带结构,电子态密度及光吸收性质,研究了相应掺杂情况下各种掺杂对锐钛矿相()电子结构及光学性能的影响.1计算方法与结构优化通过在锐钛矿型Ti().超晶胞中掺杂一个原子替代,¨原子对掺杂效应进行模拟.建立的3个模型是:2×1xl,2x2×1,3×2×1的超晶胞,这些超晶胞分别包含24,48,72个原子,对的理论掺杂浓度(原子分数,下同)为4.17,2.08,1.3【{,标记为模型(b),((t),(d);作为参照也刈'未掺杂的Ti():单胞进行了讣算,标记为模型(a),如图1所示.相应的(a),(b),(c),(d)模型k—point取样Monkhorst—pack的格点分别选取为5×5×2,5×3×2,3×3x2,3×2×2.埘品体结构优化后,找到晶体结构的最稳定点,再完成能带结构, 态密度和光学性质的计算.图1替位掺杂锐钛矿型Ti02计算模型Fig.1ThecalculationmodelsforsubstitutionalanataseTi()2通过Accelrys公司开发的Materialsstudio中的CASTEP模块,采用基于密度泛函理论(Densityfunction theory,DFT)的平面波超软赝势方法进行计算.在掺杂前后的结构优化环节中交换关联函数均采用广义梯度近似(GGA,Generalizedgradientapproximation),赝势函数采用PBE(Perdew,BurkeandErnzerhof)梯度修正函数,并在此近似下进行了结构及性质计算.其它计算参数设置为:平面波截断~(Cutoff)340eV,自洽场收敛性标准(SCFtolerance)5×10eV/atom,两次迭代体系能量收敛精度5×10eV/ atom,原子最大受力收敛精度1×lOeV/A,最大应变收敛精度2×10GPa,原子最大位移收敛精度5×10A,计算的价态电子有Ti3s.3p3d4s.,O2s2p,Co3d4s,Fe3d.4s,Zr4s4p.4d5s,V3s.3p3d.4s,WSs.5p5d6s,所有计算均在倒易空间中进行.作为后续计算基础的未掺杂rri模型,表1为经优化后锐钛矿相Ti()晶胞结构参数的计算结果n,c,"(dap/c, dap是轴向Ti一()键长)与实验值及文献值的比较.从表1中可以看出,理论计算结果l7与实验数值_8接近, 表明计算精确度高,模型可靠.表l锐钛矿相TiO2结构参数比较Table1StructureparameterofanataseTiO22结果与讨论2.1能带结构分析根据掺杂模型计算所得能带结构,各模型的禁带宽度值9Ti●O●M(掺杂原子)如表2所示.从表2中可以看出,随着Co,Fe,V掺杂浓度的增加,禁带宽度呈现出明显减小的趋势;而掺杂时不同掺杂浓度下禁带宽度几乎一致;但w掺杂下禁带宽度反而增大,甚至比未掺杂TiO的禁带宽度更大.表2计算模型的带隙宽度值Table2Bandgapofcalculationmodels考查掺杂前后禁带宽度变化最大的模型,选取费米能级为零点,纯锐钛矿相TiO:及各金属元素4.17掺杂浓度下在沿布里渊区对称点上的能带结构如图2所示.据图2(a)可以看出锐钛矿型TiO.的导带最低点及价带最高点均在G点,据此判定其为直接能隙半导体,禁带宽度为2.23eV,小于实验值3.23eV,与Asahi等的计算结果相近.由于在广义梯度近似(GGA)计算下,交换关联函数不能完全反映真实的多电子相互作用,导致得到的禁带宽度要比真实的禁带宽度小.这种由于计算方法本身造成低估带隙的情况,文献[9,10]已进行过讨论.但作为一种有效的近似方法,其结果的相对值还是准确的,不影响对能带结构的分析.由图2(b)一(f)可知,Co,Fe,Zr,V和w掺杂TiO.的导带最低点分别在G,Z,G,G,G点,而价带最高点分别位于G, F,F,F,F点.这表明Co掺杂的电子为直接跃迁,禁带宽度为0.47eV;而Fe,Zr,V和w掺杂的电子为间接跃迁,禁带宽度分别为1.70eV,2.18eV,1.78eV,2.74eV.与TiO2的金属掺杂锐钛矿相TiOz的第一性原理计算/王海东等?131? 禁带宽度2.23eV相比,w掺杂后禁带宽度变宽,而co,Fe,Zr,V均有不同程度的减小,其中C()掺杂后TiO禁带宽度最小.根据半导体掺杂理论,杂质浓度较高时杂质原子相互间较接近,因此杂质原子之间的电子波函数发生重叠,使孤立的杂质扩展成为能带,即杂质能带[1.图2(b),(c)中,Co,Fe掺杂分别在禁带中上部产生了2条和3条新杂质能级,可在电子跃迁时起中问过渡作用,能有效减小所需的激发能量,从而拓宽了Co和Fe掺杂TiO.的光响应波长范围. 42净O器一2一4-6在图2(e)中,V掺杂能级位于接近导带底的位置,与Ti3d轨道形成复合导带底.由图2(d)可知,Zr掺杂在低浓度下产生的能级不明显,新能级与O2p轨道复合形成价带顶,但Zr 掺杂与V掺杂一样也没有引人中间能级,不会形成新的空穴俘获中心,因而亦可较有效地提高T[O的光催化活性.如图2(f)所示,w掺杂后只在靠近价带下方出现了新的能级, 使价带宽度增加,对禁带影响不明显,不会使光吸收边沿发生红移.42;≈一2一4—6GFqzGGFQZGGFQzG图2能带结构Fig.2Energybandstructure2.2电子态密度分析与能带结构分析相对应,选取4.17掺杂浓度,对不同金属元素Co,Fe,Zr,V和W掺杂Ti()2在沿布里渊区对称点上的总态密度(DOS)与纯Ti02总态密度进行了比较,如图3 所示.图3总态密度图Fig.3Totaldensityofstates从图3可知,与纯TiO.相比掺杂后体系的导带和价带的位置出现了负移,且掺杂后导带的宽度均有不同程度的减小,理论上将使掺杂后的TiO.具有更强的氧化还原能力.Zr掺杂TiOz后的态密度与未掺杂TiOz的态密度基本相似, 2O一2三醣≈一4口[一6-8GFQ没有明显的变化;Co,Fe掺杂后分别在禁带中间靠近导带和靠近价带方向出现了新的态密度.在V掺杂TiO靠近导带下方出现了一个"小肩峰",使导带向低能量方向偏移,有利于禁带宽度的减小;在W掺杂靠近TiOz价带下方也出现了新的态密度"肩峰",使得价带加宽;V和W掺杂TiO.的总态密度整体向能量最低的方向偏移.掺杂前后电子结构的变化可根据费米能级附近价带和导带的偏态密度(PDOS)作进一步分析,如图4所示.由图4(a)可以看出,锐钛矿型TiO在费米能级附近的价带和导带分别主要由.原子的2p轨道和rri原子的3d轨道组成,价带范围一5.26～0.77eV,宽度为6.03eV;导带范围1.61～5.49eV,宽度为3.88eV.如图4(b)所示,Co掺杂Ti02价带(一6.40～O.36eV)主要由02p轨道组成,昆合了Ti3d和Co3d轨道,宽度为6.76 eV,比未掺杂Ti02的价带宽度明显增加;导带(2.O9～3.94 eV)主要由Ti3d轨道组成,同时也混合了Co3d和02p轨道,宽度为1.85eV,比未掺杂TiO:的导带宽度明显减小.相对未掺杂的TiO.,Co掺杂后价带向下移动0.41eV,导带向上移动0.48eV.但在导带和价带之间形成了由Co3d和O2p轨道杂化的中间能带,从而有利于价电子从价带到导带的跃迁,表现出良好的光学性能.6420>∞\∞金属掺杂锐钛矿相Ti()2的第一性原理计算/王海东等?133? 荷和更小的半径,取代后可能导致Ti什与O.卜距离变小,有利于光生电子的跃迁,而且具有更大的电荷半径比,以至于w对()一有较强的极化效应.另外一个原因是w的掺杂是高价掺杂.Kiriakidou等口认为掺杂离子的化合价高时会使费米能级和能带向上漂移,表面势垒变高,空间电荷区变窄,使光生电子和空穴在强场的作用能够得到有效的分离.图5掺杂TiO2的紫外一可见吸收光谱Fig.5UV-visabsorptionspectraofaopedTi023结论采用基于密度泛函理论的从头算平面波超软赝势方法研究了纯锐钛矿相TiO及5种不同金属掺杂TiO.的晶格常数,能带结构,电子态密度与光吸收系数.模拟计算表明:掺杂计算基础的未掺杂TiO模型,经优化后晶胞结构参数的计算结果与实验值偏差较小,参数设置合理,模型可靠. (1)掺杂后能级的变化主要是过渡金属Co3d,Fe3d,Zr4d,Zr4p,V3p,V3d,W5p,W5d轨道的贡献.随着3d过渡金属Co,Fe,V掺杂浓度的增加,禁带宽度呈减小趋势,且均在禁带中产生了明显的杂质能级;Zr掺杂前后所得结构几乎一致,与掺杂浓度无关;但w掺杂由于导带价带相对位置的变化使禁带宽度增大,并在原有价带以下产生了新的杂质能级.(2)掺杂导致禁带宽度变窄或出现新的杂质能级,在紫外一可见吸收光谱中表现为TiO吸收边沿的红移或出现新的吸收峰.其中Co,Fe掺杂的吸收边沿明显红移,而w掺杂在可见光区域出现了很强的新的吸收峰.致谢感谢q-南大学高性能计算q-心在模拟计算方面提供的技术支持与帮助.参考文献I张金龙,陈锋,何斌.光催化EM].上海:华东理工大学出版社,2004:712ChoiW,TerrainA.HoffmanMRTheroleofmetaliondopantsinquantum-sizedTiO2:Correlationbetweenphoto—reactivityandchargecarrierrecombinationdynamics[J].j PhysChem,1994,98(51):136693SegallMD,LindanJDP,ProbertMJ,eta1.First-princi—plessimulation:Ideas,illustrationsandtheCASTEPcodeLJ一].JPhys:CondensedMatter,2002,14(11):27174CaoHonghong(曹红红),HuangHaibo(黄海波),ChenQiang(陈强).AbinitiocalculationsofanataseTi()2(对锐钛矿相TiO2的第一原理计算KJ].JBeijingUniversityAero—nauticsAstronautics(北京航空航天大学),2005,31(2):2515AsalhiR,TagaY,MannstadtW,eta1.Electronicandop—ticalpropertiesofanataseTiO2口].PhysRevB,2000,61 (11):74596UmebayashiT,Y amakiT,ItohH,eta1.Analysisofelec—tronicstructuresof3dtransitionmetal—dopedTiO2basedon bandcalculations[J].JPhysChemSolids,2002,63(10):'19097TianFenghui(田风惠).Theorystudy0nnon-metallicele—mentdopedTiO2一basedphotocata1yst(非金属元素掺杂改性的Ti02基光催化剂的理论研究)[D].Shangdong(山东): ShangdongUniversity(山东大学),20068BurdettJK,HughbandksT,MillerGJ,eta1.Structural electronicrelationshipsininorganicsolids:Powderneutron diffractionstudiesoftherutileandanatasepolymorphsofti—taniumdioxideat15and295K[J].JAmChemSoc,1987,109(12):36399PerdewJP.PhysicalcontentoftheexactKohn-shamorbital energies:Bandgapsandderivativediscontinuities[J].Phys RevLett,1983,5l(20):188410V alentinCD,FinazziE,PaeehioniG,eta1.Densityfunc—tionaltheoryandelectronparamagneticresonancestudyon theeffectofN-FCo-dopingofTi()2[J].ChemMater,2008,20(11):3706l1谢希德,陆栋.固体能带理论EM].上海:复旦大学出版社, 1998:1012WengHongming,Y angXiaoping,DongJinming,eta1.E—lectronicstructureandopticalpropertiesoftheCo-doped anataseTi02studiedfromfirstprinciples[J].PhysRevB, 2004,69(12):12521913LiaoBin,ZhaoQinli,YingWuxian,eta1.Calculationofe—lectronicstructureofanataseTi02dopedwithtransition metalV,Cr,FeandCuatomsbythelinearizedaugmented planewavemethod[J].ChineseJStructuralChem,2009,28 (7):86914DuXiaosong,LiQunxiang,SuHaibin,eta1.Electronicand magneticpropertiesofV-dopedanataseTi02fromfirstprin—ciples[J].PhysRevB,2006,74(23):233201l5KiriakidouF,KondaridesDI,V erykiosXE.Theeffectof operationalparametersandTi02一dopingonthephotocataly- ticdegradationofazo-dyes[-J~.CatalToday,1999,54(1):119(责任编辑汪雁南)。

氧化钛纳米片材料的合成及其催化应用进展

CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2017年第36卷第7期·2488·化工进展氧化钛纳米片材料的合成及其催化应用进展李路1，2，徐金铭2，齐世学1，黄延强2（1烟台大学化学与化工学院，山东烟台 264005；2中国科学院大连化学物理研究所，航天催化与新材料研究室，辽宁大连 116023）摘要：氧化钛纳米片材料为一种新兴的二维层状材料，在催化、环境、能源和电子领域引起人们广泛的关注。

本文从催化研究的角度出发，综述了氧化钛纳米片材料的结构、制备方法、金属及非金属元素的掺杂、纳米片基复合材料和其在光催化、光电催化和热催化等方面的应用进展。

分析表明氧化钛纳米片材料拥有特殊的形貌和特别的物理化学性质，通过控制材料的组成及结构变化，能够实现氧化钛纳米片材料的多种功能化。

指出氧化钛纳米片材料虽然有着优良的性能，但是在实际应用中远不能满足要求。

因此，优化合成和探索新形式的二氧化钛纳米片材料，对其表面进行改性及开发具有特殊功能纳米复合材料是解决其瓶颈的有效途径。

探索催化反应过程中的反应机理，开发氧化钛纳米片基工业应用催化剂将是今后重要的研究方向。

关键词：氧化钛纳米片；层状钛酸盐；催化；合成；纳米材料中图分类号：O611.4 文献标志码：A 文章编号：1000–6613（2017）07–2488–09 DOI ：10.16085/j.issn.1000-6613.2016-2340Recent advances in titanium oxide nanosheets for catalytic applicationsLI Lu 1，2，XU Jinming 2，QI Shixue 1，HUANG Yanqiang 2（1College of Chemistry and Chemical Engineering ，Yantai University ，Yantai 264005，Shandong ，China ；2Laboratory of Catalysts and New Materials for Aerospace ，Dalian Institution of Chemical Physics ，Chinese Academy of Science ，Dalian 116023，Liaoning ，China ）Abstract: As a new class 2D layered materials ，Titanium oxide nanosheets have attracted great interest inthe fields of catalysis ，environment ，energy and electronics. In this work ，we provide an overview of the recent advance of titanium oxide nanosheets on their layered structure ，synthetic methods ，doping with metals or nonmetal ，as well as their nanocomposites and applications in catalysis. Recent researches indicate that titanium oxide nanosheets with unique structure and special physical and chemical properties can achieve multiple functions by controlling their compositions and structures. Although titanium oxide nanosheets have a lot of advantages ，they are still far from practical applications. Therefore it is demanded to explore new synthesis ，doping and modification methods ，and develop new composite materials. In addition ，the reaction mechanism in the catalytic reaction process and the industrial application of titanium oxide nanosheets will be important research directions in the future. Key words ：titanium oxide nanosheets ；layered titanate compounds ；catalysis ；synthesis ；nanomaterials助理研究员，从事有序介孔材料合成及表面修饰和生物质催化转化制化学品相关科研工作。

直流磁过滤电弧源沉积氧化钛薄膜的光学特性

直流磁过滤电弧源沉积氧化钛薄膜的光学特性弥谦;刘哲【摘要】为了探索电弧源离子镀技术制备的氧化钛薄膜的透射率、消光系数和折射率,利用直流磁过滤电弧源在K9玻璃基底上制备了氧化钛薄膜,通过分光光度计和椭偏仪对薄膜的透射率、折射率和消光系数等光学特性和沉积速率进行分析研究.研究结果表明:波长在400～700nm之间,氧化钛薄膜的折射率为2.3389～2.1189；消光系数在10-3数量级上,消光系数小,薄膜吸收小,薄膜峰值透射率接近K9基底的透射率；沉积时间30min,薄膜的厚度是678.2nm,电弧源离子镀技术沉积氧化钛薄膜的平均速率为22.6nm/min.%To search magnetic filtration DC arc ion plating technique in depositing optical film, TiO2 thin film is deposited onK9 using magnetic filtration DC arc ion plating and its optical property is studied using spectrophotometer and ellipsometer . The results of analyse; Transmissivity is high; Wavelength is between 400~700 nm; Index of refraction is between 2. 3657~2.1082; Optical extinction coefficient is 10-3; Deposition rate is 22. 6 nm/min. The results suggest that magnetic filtration DC arc ion plating could deposite TiO2 thin film with small optical extinction coefficient and good index of refraction which is approximate to that of base material, fast deposttion rate and high target material use ratio. So it has great potential at optical thin film deposition.【期刊名称】《西安工业大学学报》【年(卷),期】2012(032)004【总页数】4页(P270-273)【关键词】直流磁过滤电弧源;氧化钛薄膜;光学特性;沉积速率【作者】弥谦;刘哲【作者单位】西安工业大学光电工程学院,西安710032;西安工业大学光电工程学院,西安710032【正文语种】中文【中图分类】O484.4+1电弧源离子镀技术自俄罗斯在20世纪70年代推广以后，现广泛应用于制备硬质膜和装饰膜等［1］，但是在制备光学薄膜方面的应用比较少.文中分析了利用电弧源离子镀技术制备的氧化钛薄膜的透射率、折射率和消光系数等光学特性及沉积速率，对电弧源离子镀技术在制备光学薄膜方面的应用进行了探索.氧化钛是光学薄膜中常用的一种高折射率材料，文献［2］利用阴极电弧源制备了晶体氧化钛并研究了它的化学和力学性能.文献［3］利用脉冲偏压电弧离子镀沉积非晶氧化钛薄膜，研究了薄膜的光学特性.直流磁过滤电弧不仅离化率高，离子动能高，且大量减少了电弧源蒸发本身所带来的“大颗粒”［4－5］，沉积的薄膜表面形貌好，若应用在制备光学薄膜上，光学薄膜的沉积效率和靶材利用率有很好的改善.文中利用直流磁过滤电弧源在K9基底上制备氧化钛薄膜，利用分光光度计，椭偏仪对氧化钛薄膜的光学特及沉积速率性进行分析研究.1 实验原理直流磁过滤电弧源离子镀是通过电弧放电，电离阴极靶材和真空室阳极之间的气体，电离度达80%以上［6］，阴极靶表面发生场致电子发射和热致发射，阴极材料以蒸汽状态进入真空室内，金属原子与电子，离子发生非弹性碰撞电离，离子动能最高可达100 e V，靶材离子在电磁场的作用偏转90°，与氧气离子反应生成氧化钛沉积在玻璃基底上，而弧源蒸发出的原子和中性粒子则不受电磁场的作用，在惯性的作用下直接沉积到真空室壁上［7］.实验用的镀膜设备是俄罗斯的УВНИЛА-1－001型等离子体镀膜机.图1是磁过滤电弧源离子镀设备的原理图，电弧放电离化靶材，钛离子通过磁场和电场的作用偏转并与氧气离子反应，沉积在K9基片上［8－10］.而弧源蒸发出的中性粒子团簇直接沉积到真空室壁上，不会影响薄膜表面质量.2 实验工作参数实验选用的靶材为高纯度钛靶，基底为K9玻璃，在放入真空室前用乙醚和无水乙醇为1∶3混合的溶液清洗，真空室本底真空为5×10－3 Pa，充入氧气后工作气压为9×10－1 Pa，靶电流55 A，靶基距220 mm，沉积时间30 min.图1 磁过滤电弧源离子镀的原理图Fig.1 Principle of the magnetic filtration DC arc ion plating3 氧化钛薄膜的检测及分析利用日立U－3501型分光光度计测量薄膜的透射率，美国J.A.Woollam公司制造生产的 M－2000UI型宽光谱变角度椭偏仪分析薄膜的折射率，消光系数和薄膜厚度.3.1 透射率图2是氧化钛薄膜的透过率曲线图，未镀膜的K9玻璃基底的透射率是92%，镀膜后氧化钛薄膜的峰值透射率基本接近基底的透射率，氧化钛薄膜的吸收小，透射率良好，这说明制备的氧化钛薄膜中，金属钛离子的氧化度高，因为不完全氧化的钛离子吸收比较大.图2 氧化钛薄膜与K9基底的透射率Fig.2 Transmittance of the TiO2 thin film and K9从图2可以看出薄膜存在微弱的吸收，这是因为利用电弧源离子镀技术镀膜时，当靶上加电压的瞬间，靶材先蒸发离化，然后氧气才会被电离，在这一瞬间，会存在很少一部分靶材离子氧化不完全，但是很快离子就会形成稳定状态，所以氧化钛薄膜在400 nm附近就会存在微弱的吸收.用离子束辅助反应电子束蒸发技术制备的TiO2薄膜在400 nm附近也存在同样的微弱吸收.3.2 折射率图3是氧化钛薄膜的折射率随波长的变化曲线，折射率的色散属于正常色散，波长在400～700 nm之间，折射率为2.3389～2.1189，薄膜的折射率小于块体TiO2材料的折射率，这是由于沉积的薄膜结构存在缺陷，致密度小于1造成的.薄膜折射率由沉积的氧化钛材料的折射率和薄膜中存在的孔隙的折射率组合而成，因此薄膜的折射率小于块体材料的折射率，若把片子放置在潮湿的环境中一段时间，薄膜的折射率会因为孔隙中充满水，孔隙的折射率增加，从而薄膜的折射率增加. 图3 氧化钛薄膜的折射率随着波长变化曲线Fig.3 Indexof refraction of the TiO2 thin film changing with wavelength3.3 消光系数氧化钛薄膜的消光系数随波长的变化曲线如图4所示.图4 氧化钛薄膜的消光系数随波长变化曲线Fig.4 Extinction coefficient of the TiO2 thin film changing with wavelength在可见光范围内消光系数均在10－3数量级上，消光系数小，薄膜的吸收小.电弧源离子镀技术的靶材离化率较高，当氧气流量达到一定值时，沉积到基片上的钛离子氧化完全，薄膜的吸收小.但是当氧气流量过大，真空室内工作气压过高，降低了真空室内的离子平均自由程，使得到达基片的钛离子数量减少，膜层沉积速率降低，到达基片的钛离子动能也会减小，薄膜结构疏松，使薄膜的折射率减小.因此利用电弧源离子镀技术制备氧化钛薄膜时当靶电流一定时，需要选择适当的氧气流量.3.4沉积速率氧化钛薄膜的沉积时间是30 min，通过椭偏仪分析，薄膜的厚度为678.2 nm，平均沉积速率为22.6 nm／min，电弧源离子镀技术沉积薄膜的速率快.电弧源离子镀技术离化率较高，相应沉积速率就比较快，沉积薄膜的速率主要与靶电流，氧气流量的大小有关.当氧气流量一定时，靶电流越大，靶材离化率越高沉积速率快；当靶电流一定时，氧气含量增加一定值时，沉积速率会达到最大，但是当氧气流量继续增加时，沉积速率减慢.4 结论1）利用直流磁过滤电弧源离子镀技术制备的氧化钛薄膜，在可见光和红外光范围内，吸收系数小，有较好的透射率，电弧源离子镀技术的平均沉积速率22.6 nm／min，薄膜折射率为2.3389～2.1189.2）电弧源离子镀技术沉积薄膜还具有靶材利用率高的特点.3）通过分析电弧源离子镀技术制备氧化钛薄膜的折射率，消光系数及沉积速率，表明电弧源离子镀技术可以应用在制备光学薄膜方面.【相关文献】［1］唐晋发，顾培夫，刘旭，等.现代光学薄膜技术［M］.杭州：浙江大学出版社，2006.TANG Jin－fa，GU Pei－fu，LIU Xu，et al.The Morden Optical Thin Film Technology［M］.Hangzhou：Zhejiang University Press，2006.（in Chinese）［2］周友苏，张立珊.阴极电弧源镀制TiO2薄膜的研究［J］.现代制造工程，2003，8（增）：36.ZHOU You－su，ZHANG Li－shan.Study of TiO2 Thin Film Plating by Cathode Electric Arc Source［J］.Machinery Manufacturing Engineer，2003，8（S）：36.（in Chinese）［3］张敏，林国强，董闯，等.脉冲偏压电弧离子镀TiO2薄膜的力学与光学性能［J］.物理学报，2007，12（56）：12.ZHANG Min，LIN Guo－qiang，DONG Chuang，et al.Mechanicaland Optical Properties of Titanium Dioxide Films Prepared by Pulsed Bias Arc Ion Plating ［J］.Acta Physica Sinica，2007，12（56）：12.（in Chinese）［4］王少鹏，潘晓龙，李争显，等.靶电流对电弧离子镀TiAl N膜层组织及成分的影响［J］.真空科学与技术学报，2008，28（增）：64.WANG Shao－peng，PAN Xiao－long，LI Zheng－xian，et al.Influence of Target Current on Microstructures and Stoichiometries of TiAl N Coating Deposited by Arc Ion Plating［J］.Chinese Journal of Vacuum Science and Technology，2008，28（S）：64.（in Chinese）［5］王明东，朱道云，郑昌喜，等.沉积气压对电弧离子镀制备ZnO薄膜的结构和性能影响［J］.功能材料，2007，38：6.WANG Ming－dong，ZHU Dao－yun，ZHENG Changxi，et al.The Influence of Working Gas Pressure to ZnO Thin Film’s Structure and Performance Deposited by Arc Ion Plating［J］.Function materials，2007，38：6.（in Chinese）［6］樊勇.真空阴极弧离子镀的发展及应用［J］.新技术新工艺，2008（4）：93.FANYong.Development and Applications of Cathodic Vacuum Arc Deposition［J］.New Technology and New Process，2008（4）：93.（in Chinese）［7］姜雪峰，刘清才，王海波.多弧离子镀技术及其应用［J］.重庆大学学报：自然科学版，2006，29（10）：10.JIANG Xue－feng，LIU Qing－cai，WANG Hai－bo.Multi－arc Ion Plating Technology and Apply ［J］Journal of Chongqing University：Natural Science Edition，2006，29（10）：10.（in Chinese）［8］李洪波，孙丽丽，吴国松，等.新型双弯曲磁过滤阴极真空电弧沉积系统的磁场模拟计算［J］.真空科学与技术学报，2008，29（5／6）：3.LI Hongbo，SUN Li－li，WU Guo－song，et al.Simulation of Magnetic Field Distribution in Doubly Bent Filter Cathode of Vacuum Arc Film Growth Setup［J］.Chinese Journal of Vacuum Science and Technology，2008，29（5／6）：3.（in Chinese）［9］杨陈，樊慧庆，李创，等.离子束辅助反应电子束蒸发TiO2薄膜的结构和光学性能［J］.材料科学与工程学报，2007，25（2）：1.YANG Chen，FAN Hui－qing，LI Chuang，etal.Structure and Optical Properties of TiO2 Thin Film Deposited by Ion Beam Assistant Reactive Electron Beam Evaporation［J］.Journal of Materials Science and Engineering，2007，25（2）：1.（in Chinese）［10］潘永强，朱昌，弥谦，等.电子束蒸发TiO2薄膜的光学特性［J］.应用光学，2004，25（9）：5.PAN Yong－qiang，ZHU Chang，Mi Qian，et al.The Optical Properties of TiO2 Thin Film Prepared by Electron Beam Evaporation［J］.Applied Optics，2004，25（9）：5.（in Chinese）。

白藜芦醇负载的TiO_2纳米管阵列抑制炎症反应促进骨修复及其机制的研究

白藜芦醇负载的TiO_2纳米管阵列抑制炎症反应促进骨修复及其机制的研究钛及其合金因具有良好的机械性能、生物相容性和耐腐蚀性被广泛应用于骨植入材料。

但是钛表面具有生物惰性,而且在植入早期阶段,植入物周围发生的炎症反应,阻碍骨修复和骨整合,因此常出现植入失败的现象。

将钛合金表面进行纳米化改性,并负载抗炎症药物等,开发新型功能涂层,已成为钛合金骨植入材料的研究热点和重点。

在本研究中,通过电化学阳极氧化技术,在钛表面制备了尺寸均一的二氧化钛纳米管阵列,再将白藜芦醇负载到纳米管阵列表面,实现了药物的原位释放。

以脂多糖刺激的巨噬细胞作为早期炎症模型,12月龄小鼠的骨髓间充质干细胞作为成骨分化模型细胞,对该纳米涂层降低活性氧释放,抑制早期炎症,促进成骨分化的生物效应进行研究。

结果显示,工业纯钛经过电化学阳极氧化处理后,二氧化钛纳米管均匀排列在材料表面;然后通过物理吸附作用使白藜芦醇覆盖在纳米管表面上,制备出负载白藜芦醇的二氧化钛纳米管阵列表面。

与纯钛对照组相比较,该表面能显著抑制脂多糖诱导的巨噬细胞的炎症反应,抑制效果与负载的白藜芦醇的量呈剂量相关性。

当白藜芦醇负载量为15μg/cm~2时,活性氧浓度降低约50%,对NO抑制率达到75%,炎症相关因子TNF-α和IL-1β的蛋白表达分别降低约88%和82%,在分子水平上,与纯钛组相比,TNF-α和IL-1β以及iNOS的mRNA表达水平也显著降低。

同时,该表面能降低成骨细胞中活性氧的表达,抑制率达到36%,该表面也能显著促进成骨细胞中碱性磷酸酶和钙结节的表达,提高成骨分化相关因子ALP、OCN、OPN、COL-1和Runx2的上调,而且TNT-Res成浓度依赖性降低了巨噬细胞和成骨细胞中NF-κB的磷酸化水平。

以上结果表明,经过阳极氧化和负载白藜芦醇后的钛材料可以通过抑制NF-κB信号通路的激活来显著抑制早期炎症反应,促进成骨分化,TNT-Res(Resveratrol-Titanium dioxide nanotubes)可能是提高骨整合能力的有效植入物。

定向原位生长TiO2纳米条涂层及其固相微萃取性能研究

第50卷第5 期 2021 年 5 月
辽宁化工 Liaoning Chemical Industry
Vol.50, No. 5 May, 2021
定向原位生长Ti〇2纳米条涂层及其固相微萃取性能研究
张雷1' 杜新贞0
( 1 . 西北师范大学化学化工学院，甘肃兰州 730070; 2 . 甘肃省生物电化学与环境分析重点实验室，甘肃兰州 730070 >
JWD-12.2精密电源，上海市卢湾教学电子仪器厂； Ultra P lu s扫描电子显微镜，附 AztecX-80能量色散 X-射线光谱仪，Zeiss, 德国； Waters 600 HPLC系统，附 2487可变波长检测器，Waters，美国； Agilent Zorbax SB-C18 色谱柱，150mm x 4_6 mm， 5 m。100 nm 聚二甲基硅氧烷（ PDMS )纤维和 85 nm 聚丙烯酸酯（PA ) 纤维，Supelfo, 美国。 1.3 Ti@ Ti0 2N S s 纤维的制备
二氧化钛（Ti0 2) 作为一种极具开发前景的无机功能性氧化物 [8]，具有高化学稳定性和良好的耐腐蚀性，在 T i丝基体上原位生长Ti0 2纳米形貌所制备的 SPME纤维具有良好的吸附能力本研究在 T i丝上通过阳极氧化的方法定向原位生长了二氧化钛纳米条（Ti@ TiO:NSs) 涂层，将其与高效液相色谱-紫外检测器（HPLC-UV )联用，检测其对多环芳烃（ PAHs ) 萃取能力，在优化实验条件下，成功对真实水样中的目标 PAHs进行了富集与测定。

梯度纳米结构铁高应变率变形的力学性能和微观机理研究

梯度纳米结构铁高应变率变形的力学性能和微观机理研究陈萍1)，袁福平，武晓雷（非线性力学国家重点实验室，中国科学院力学研究所，北京100190)摘要：纳米晶金属具有高强度低塑性的特点，通过对梯度纳米结构金属的研究发现，由于应变局部化被抑制，梯度纳米结构材料能够实现强度与塑性的良好匹配，具有较高的研究意义。

本文利用表面机械碾磨处理(Surface Mechanical Grinding Treatment, SMGT)方法制备了梯度纳米结构铁，通过准静态压缩以及分离式霍普金森压杆动态压缩实验，研究了梯度纳米结构铁的塑性变形行为，并与粗晶铁的塑性变形行为作对比。

研究结果表明：相同应变率下，相比粗晶铁，梯度纳米结构铁具有较高的强度、较高的流动应力、较低的加工硬化能力和较低的应变率敏感性；梯度纳米结构铁流动应力的大小随着应变率的增加而增加，同时在动态条件下材料出现软化行为；与纳米晶铁不同的是梯度纳米结构铁在动态压缩条件下并没有形成绝热剪切带，这是由于加工硬化率下降速度减缓了，与纳米晶铁相比梯度纳米结构铁还是具有较好的加工硬化能力。

研究结果可为理解BCC梯度纳米结构金属高应变率变形的微观机理提供依据。

关键词：梯度纳米结构铁；表面机械碾磨处理；高应变率变形；分离式霍普金森压杆引言与粗晶金属相比，超细晶/纳米晶金属具有许多优越的力学性能，比如高强度的特性[1-2]，这是由于纳米晶位错滑移被晶界阻碍所造成的。

但是由于存储位错的能力低，超细晶/纳米晶金属同时具有较低的加工硬化能力和塑性/韧性，这一特性在动态条件下更为明显，其中一个主要原因就是绝热剪切带的形成[3-7]。

为了提高纳米晶的塑性，提出了梯度纳米结构的概念。

把纳米晶铜薄膜粘附在基体上可以增加纳米晶的均匀拉伸伸长率，但弹性不匹配以及界面的相互作用使得材料均匀拉伸伸长率只提高到10%[8]。

卢柯课题组也提出表面为纳米晶，心部为粗晶，中间为过渡晶粒的梯度材料[9]。

钛白粉的性质

热稳定性

二氧化钛属于热稳定性好的物质
项目相对密度(g/cm3) 表观密度(g/cm3) 莫氏硬度介电常数熔点/℃ 空气中熔点/℃ 富氧中熔点/℃ 沸点/K 比热容(25℃)/[kJ/(kg· K) 导热率/W/(m· K)
锐钛型 3.8~3.9 0.6~0.7 5.0~6.0 48 0.71 1.80

根据可见光谱长范围400~700nm，所以理想的二氧化钛粒径应0.2~0.5μm，但是人们的视觉总认为蓝白色比纯白色更白，因此都倾向于生产0.2μm粒径左右的二氧化钛，从这一点来讲消除金红石型二氧化钛固有黄相是有可能的。从图5-12可以看出0.2μm的小粒径比0.3μm的大粒径能反射更多的蓝光和绿光而显得更白。表5-7为二氧化钛在不同波长下的最佳粒径。
四类二氧化钛的性能
类型性能 TiO2%(最小)
Ⅰ
97
Ⅱ
93
Ⅲ
92 91
Ⅳ a 82 b
密度/(g/cm3)
表面积/(m2/g)
4.20
4.05
4.05
4.00
3.70
28.8 30 55 低 13.0
11.06.6-7.7 12.017.7 12.8 18.0 19 30 中等 3.5 15-19 30 中等 3.6 24 35 高 4.9
金红石型 4.2~4.3 0.7~0.8 6.0~7.0 114 1850 1830±15 1879±15 3200±300 0.71 0.620
熔解热/(kJ/mol) 生成热/(kJ/mol) 润湿热/(J/cm2) 摩尔标准热容/[J/(mol· ℃)] 摩尔标准热焓/[J/(mol· ℃)] 摩尔标准熵/[J/(mol· ℃)] 升华热(25℃)/J/g 摩尔标准自由能/(kJ/mol) 汽化热/J/g

四年级下册纳米技术就在我们身边仿写英语作文

四年级下册纳米技术就在我们身边仿写英语作文全文共3篇示例，供读者参考篇1Nanotechnology All Around UsHave you ever heard of nanotechnology? It's this super cool science about working with things that are extremely tiny - even smaller than a strand of hair or a grain of sand! Nanotechnology deals with objects called "nanomaterials" that are measured in nanometers. One nanometer is a billionth of a meter! That's crazy small.Nanomaterials behave differently than regular sized materials because of something called "quantum effects." I'm not totally sure what that means, but I know it has to do with how atoms and molecules act when they are nanosized. Anyway, because nanomaterials are so tiny, they can be used to make amazing new inventions and products that are stronger, lighter, cleaner, and more precise than what we have today.Nanotechnology is present in so many things we use every day! Lots of electronics like computers, TVs, and phones have nanocomponents inside them to make them faster and withmore memory. There are also nanomaterials in cosmetics, sunscreens, and treatments for skin because the super small particles can deliver vitamins and moisture deep into our skin. Pretty cool, right?Some of the coolest nanotechnology is used to treat diseases and keep people healthy. Researchers are working on teeny tiny nanorobots and nanoparticles that can go inside our bodies to detect diseases like cancer at a really early stage before we even know we're sick. The nanorobots could then target just the cancerous cells and destroy them without harming healthy cells. How amazing would it be to have a cure for cancer because of nanotechnology?! Scientists are also using nanomaterials to make artificial human tissue and organs that a person's body won't reject after a transplant.Another way nanotechnology helps with medicine is with nanofibers that can act as tiny bandages to cover up wounds and scrapes. Some of these nanofiber bandages have antimicrobial coatings to keep germs away and prevent infections while you heal. When my little brother fell off his bike last summer and got a nasty scrape, the nanobandage made it better way quicker than a regular cloth bandage.My favorite nanotech is something called "self-cleaning surfaces." Certain nanomaterials are hydrophobic, which means they repel water and don't let it stick around. Manufacturers can apply these waterproof nanocoatings to things like car windshields, windows, tiles, and even clothes and shoes! Any water, mud, or dirt just beads up and rolls right off instead of staining the surface. Imagine how easy it would be to clean dishes, floors, or your bathroom if everything was self-cleaning thanks to nanotechnology! My mom would love that for sure.Certain nanomaterials can also be mixed into regular products like paints, concrete, plastics, and fabrics to make them stronger and more durable. For example, nanoparticles allow concrete to be way more resistant to cracking, crumbling, and weathering from the elements. Some nanotech concretes could even repair themselves if they do get small cracks! Carbon nanotubes are another nanomaterial that is incredibly strong and lightweight and can reinforce things like vehicle bodies, sports equipment, and building materials.I think one of the coolest ways nanotechnology will impact our future is how it could improve energy production and storage. Scientists have made solar panels way more efficient by using nanoparticles that absorb more sunlight and convert it intoelectricity. There is also nanotech research into better batteries and fuel cells that could power cars, trucks, and other vehicles with little to no pollution or emissions. Someday we might have TVs, computers, and phones that use nanosized components to run for years without ever needing to be recharged!On the other hand, while I'm excited about all the potential benefits of nanotechnology, I know there are also risks we need to be aware of. Some people are worried that certain nanomaterials could be toxic if they get inside our bodies and mess with our cells in a bad way. More research is still needed to study the long-term effects nanoparticles may have on human health and the environment. We should be careful and make sure nanotech is being developed and used safely.Overall, while nanotechnology may sound like just tiny science stuff, it is crazy awesome and revolutionary! From zapping diseases to giving us self-cleaning clothes, to unlocking new energy sources, nanotechnology has the potential to help solve many of the world's biggest problems. I can't wait to see what other mind-blowing nanotech inventions scientists come up with next. The future of nanotechnology is surely going to be unimaginably small...and huge at the same time!篇2Nanotechnology is All Around UsBy [Your Name]Hey there friends! Today I want to tell you all about something super cool and kinda mind-blowing - nanotechnology! I know that sounds like some crazy science fiction thing, but it's totally real. Nanotechnology is the study and use of things that are incredibly tiny, smaller than you can even see with your eyes or a regular microscope. We're talking NANO-sized, like a nanometer which is a billionth of a meter! That's wayyyy smaller than a grain of salt or sand.At first, I thought nanotechnology was just about making robots that are tiny enough to go inside people's bodies to fix them from the inside. That would be so awesome! I've seen movies like Innerspace where a scientist gets shrunken down to microscopic size and goes inside someone's body. He got to see all their guts and everything up close. Wild, right? Well, it turns out nanotechnology is about a lot more than just that, though making tiny medical nanorobots is definitely part of it.Nanotechnology is being used in all sorts of products we use every single day without even realizing it! Take my slick new water-proof rain jacket for example. The fabric has nanomaterials embedded in it that make it repel water like magic. Thenanoparticles create a protective coating that causes water to form little beads and roll right off instead of soaking through. So cool! The same technology is used for stain-resistant khaki pants too. Nanotechnology is what allows them to stay looking fresh and new even if you spill stuff all over them.Another place you'll find nanotechnology is in sunscreens and cosmetics. Certain minerals like zinc oxide and titanium dioxide can be made into nanoparticles that block UV rays from the sun. They get rubbed right into sunscreen lotions and makeup to protect your skin without leaving that gross white residue that the regular sized particles cause. Mom loves her tinted moisturizer with nanoparticle sunscreen in it - it protects her skin while also evening out her complexion.Speaking of skin products, some biotech companies are working on nano-patches and bandages that could automatically detect and treat skin infections or injuries. The patches would have teeny tiny sensors to monitor for bacteria and smart nanoparticles that release medicine right where it's needed. No more having to rip off big clumsy band-aids every day - these smart nano band-aids would do everything for you!One of the coolest potential future uses of nanotechnology is in electronics. Get this - nanochips and components couldsomeday let us build computers that are the size of a grain of rice or even smaller! We're talking ultra-portable, incredibly powerful nanocomputers. Or what about flexible electronics like TVs and tablets that can bend and roll up like a piece of paper? Nanotechnology could lead to things like displays built into clothes or realistic 3D hologram projectors. The possibilities are limitless and amazing!It's not just computers and tech though - nanotech could revolutionize things like solar panels too. By usingnano-engineered materials to capture sunlight and convert it to electricity way more efficiently, we could power entire cities and towns from a few small nano solar farms. It could help cut down on pollution from dirty fossil fuels and make clean renewable energy affordable for everyone around the world. That would be a total game-changer!Of course, with something this advanced there are definitely risks too that the scientists have to be careful about. We have to make sure nanoparticles can't accidentally get inhaled or contaminate the environment. There are still a lot of unanswered questions about the long-term effects of being exposed to certain nanomaterials. But as long as it's properly tested andregulated, nanotechnology has the potential to completely transform our lives for the better.From stain-resistant clothes to super computers to renewable energy to curing diseases, nanotechnology is going to be a big part of the future whether we realize it or not. And you know what? I can't wait! It sounds like the stuff of science fiction, but it's very real science happening right now all around us. I'll be watching for all the amazing nanotech breakthroughs still to come. Who knows, maybe I'll even get to have my own pet nanorobot someday!篇3Nanotechnology is All Around UsHave you ever heard of nanotechnology before? It's such a cool and fascinating branch of science! Nanotechnology deals with things that are extremely tiny - way smaller than what we can see with our naked eyes. We're talking about objects that are measured on the nanometer scale. One nanometer is a billionth of a meter! That's unimaginably small.To give you an idea of just how miniscule that is, a single strand of human hair is around 80,000 nanometers wide. Crazy, right? Working with things at the nanoscale allows scientists tomanipulate individual atoms and molecules. This allows them to create new materials and technologies with amazing properties.Nanotechnology might sound like some far-off science fiction concept, but it's actually all around us in our everyday lives already! There are so many incredible examples of nanotechnology being used in really neat ways. Let me tell you about some of the mind-blowing applications of this super tiny tech.One place you'll find nanotechnology is in electronics like computer chips, phones, and TVs. Transistors and other components in these devices are now being made at the nanoscale, which allows them to be packed together more densely. This makes our gadgets faster, more powerful, and more energy efficient. Perhaps one day, we'll have molecular computers and storage devices made entirely of nanomaterials!Another amazing use of nanotechnology is in medicine. Scientists are developing tiny nanoparticles and nanorobots that can actually travel inside the human body! These could one day be used to deliver medication directly to diseased cells, detect health problems incredibly early, and even repair damaged cells and tissues. Isn't that awesome? We might be able to beatillnesses like cancer and Alzheimer's with the help of nanotechnology.Nanotechnology is also being used to create new materials that are stronger, lighter, and more durable than anything we've ever seen. Some examples are carbon nanotubes and nanomaterials like graphene. With these super materials, we could build lighter and more fuel-efficient vehicles and aircrafts. We might even be able to construct incredible structures like space elevators one day! The applications in engineering and manufacturing are really exciting to think about.Another really cool use of nanotechnology is for environmental purposes. Nanoparticles can actually help clean up pollution in our soil and water by absorbing toxic chemicals. Nanotech membranes are being developed for water purification too. And certain nanomaterials could potentially help make solar panels and fuel cells way more efficient at generating clean energy. How neat is that?Even in everyday products we use, there are nanotech applications all around us. Some foods already take advantage of nanomaterials to make them more flavorful or have a longer shelf life. Nanoparticles are being added to make sunscreen more effective at blocking UV rays. Sporting goods like tennisballs and baseball bats are using nanocomposite materials to be lighter and stronger. Even some thin, stain-resistant clothing is using nanomaterials! The possibilities seem almost endless.As you can see, nanotechnology might be super small, but it's being used for huge achievements all around us. I can hardly wait to see what other breakthroughs nanotech will lead to in computers, robotics, energy, manufacturing, and so many other fields. We're really just scratching the surface of the potential of this incredible technology.I find it all so fascinating to think that materials and devices made by manipulating individual atoms and molecules are impacting our lives already. And this is only the beginning! Who knows what kinds of revolutionary nanomaterials and nanotech applications scientists will develop next. I wouldn't be surprised if nanotechnology changes our world in unimaginable ways in the decades to come.What was once confined to science fiction is now a reality thanks to our ability to precisely control matter at the nanoscale. It really makes you wonder what other incredible breakthroughs are just around the corner. I know that nanotechnology will continue to lead to all kinds of exciting innovations that couldvastly improve our lives and our world. In fact, it's probably impacting us in ways we can't even fathom yet!So the next time you're using your phone, putting on sunblock, or grabbing a sports drink, just think about the nanotechnology at work all around you. Who would have ever imagined that scientists could engineer things at such a minuscule level? Yet that's exactly what's happening and leading to so many amazing real-world applications. It just goes to show that even the smallest of things can have huge impacts on our world!。

二氧化钛表面超强酸化光氧复合降解罗丹明B

第40卷第2期2021年3月Vol.40No.2Mar.2021大连工业大学学报JournalofDalianPolytechnicUniversityDOI：10.19670/ki.dlgydxxb.2021.0210二氧化钛表面超强酸化光氧复合降解罗丹明B温宇，杨大伟(大连工业大学轻工与化学工程学院，辽宁大连116034)摘要：采用共结晶方法制备了锌锆共掺杂的介孔二氧化钛，前驱体用硫酸处理使其具有超强酸性。

将制备的介孔二氧化钛用于降解废水模拟物罗丹明B,测试其光催化与氧催化降解能力。

通过紫外-可见分光光度计、X射线衍射、电镜扫描等对催化剂进行表征，实验结果表明，在强酸修饰二氧化钛前驱体的影响下，掺杂锌锆的介孔二氧化钛具有光催化与氧催化活性。

锌锆共掺杂介孔二氧化钛的光催化与氧催化效率分别达到了72%与25%o硫酸处理后在TiO2与掺杂原子表明形成酸性中心，在无光条件下氧化降解废水效率为30%,提高了降解效率。

关键词：二氧化钛；光催化；酸催化；罗丹明B中图分类号：X703.5文献标志码：A文章编号：1674-1404(2021)02-0136-04Composite degradation of rhodamine B using TiO2withphotocatalytic oxygen and super acidWEN Yu,YANG Dawei(SchoolofLightndustryandChemicalEngineering,DalianPolytechnicUniversity,Dalian116034,China) Abstract:The mesoporous titania doped with zinc oxide,zirconium dioxide,zinc and zirconium were prepared by the co-crystallization method and the precursor of mesoporous titania was pretreated with sulfuric acid to endowed it super acidic.The mesoporous titania was used for degradation of rhodamine B in simulated wastewater and its photocatalytic activity and oxygen catalytic ability was analyzed by UV-visible spectrophotometer,X ray diffraction,scanning electron microscopy.The results showed that the T1O2doped metal oxides and super acid exhibited excellent photocatalytic and oxygen catalytic ability.The degradation rate of rhodamine B photocatalyzed and oxygen catalyzed by the prepared catalysts were72%and25%,respectively.After treatment with sulfuric acid,the acidic centers were formed between the doped atoms and the surface of titanium dioxide,which improved the oxygen degrading efficiency of wastewater to30%.Keywords：TiO2;photocatalytic;acidic catalysis;rhodamine B0引言工业生产中生成的有机废水对环境造成严重污染,国家对废水排放标准执行越来越严格,如何降低或消除有机废水中大分子有机物成为研究的重点。

纳米tio2透皮行为及紫外光诱导下致皮肤损伤研究

摘要纳米二氧化钛(纳米TiO2)是一类新型的无机纳米材料，近年来被广泛应用于化妆品、服装、环境保护等领域。

由于纳米TiO2具有较强的光化学活性，大量使用与人体皮肤接触，其皮肤安全性引起人们的广泛关注。

目前，国内外关于纳米TiO2的毒性研究大都来自体外和短期的动物毒性实验，未见系统的纳米TiO2透皮行为及紫外光（UV）诱导下致皮肤损伤机制的研究。

本论文研究了不同粒径（4～90 nm），不同晶型（锐钛矿型、金红石型、混合晶型）纳米TiO2的离体、在体透皮行为以及器官蓄积；研究UV诱导下纳米TiO2产生活性氧自由基（ROS）的途径和对人角质形成细胞（HaCaT）的损伤机制；探讨抗氧化剂N-乙酰半胱氨酸（NAC）降低纳米TiO2的氧化损伤效应。

开展的主要工作如下：（1）采用水平透皮扩散池，研究纳米TiO2离体透皮行为，以乳猪和Bulb/c裸鼠为模型，研究纳米TiO2在体透皮行为。

离体透皮结果表明：不同粒径及晶型的纳米TiO2均没有透过猪耳皮肤角质层，胶带剥离实验结果提示纳米TiO2主要沉积在皮肤表面的毛孔及褶皱中。

在体透皮结果表明：乳猪猪耳皮肤在体透皮30 d后，通过透射电子显微镜（TEM）及病理组织切片观察，纳米TiO2可穿透猪耳皮肤角质层，进入表皮，且可进入表皮细胞胞浆内，并对细胞产生一定程度的损伤，主要表现为细胞核周围出现空泡及细胞间隙模糊，细胞间桥粒连接消失；Bulb/c裸鼠整体透皮60 d 后，不同晶型及粒径纳米TiO2均不同程度的穿透裸鼠皮肤，进入皮下各组织和脏器中，并引起相应的组织病理学改变，主要表现为组织炎性细胞浸润及灶性坏死，裸鼠暴露皮肤出现褶皱加深、松弛、无光泽等老化现象，光镜下皮肤组织呈现表皮角化过度、表皮变薄及深层细胞萎缩等病理学改变，皮肤组织匀浆样品中羟脯氨酸(HYP)含量、超氧化物歧化酶（SOD）水平显著降低，丙二醛（MDA）含量明显上升。

试验结果提示皮肤老化及损伤均与氧化应激相关。

碲化铬cr

碲化铬cr
碲化铬（Cr2Te3），又称碲化铬、二铬碲化物，是一种化学品，英文名称为Chromium(III) telluride，在常温常压下稳定，具有铁磁性。

其物理性质如下：
- 密度（g/mL,25℃）：7.12；
- 作用与用途：避免光，明火，高温。

空气中稳定。

不溶于水，溶于酸；
- 合成方法：铬与适量碲粉在真空密封石英管中于1000℃加热24h或更久便得Cr2Te3；
- 贮存方法：常温密闭，阴凉通风干燥。

南京大学王学锋教授、张荣教授团队曾与多个课题组合作，利用脉冲激光沉积技术在蓝宝石衬底上高质量外延了大面积铁磁碲化铬（Cr5Te6）单晶薄膜，从中观察到了巨大的拓扑霍尔效应，拓扑霍尔电阻率在90K时高达1.6μΩ·cm，是当前在CrxTey家族体系中所见文献报道的最大值。

莱斯大学发现新型超硬钛- 金合金硬度为钛4 倍

莱斯大学发现新型超硬钛- 金合金硬度为钛4 倍
作者：暂无
来源：《新材料产业》 2016年第9期
莱斯大学（Rice University）的一组科学家在物理实验室创造出了一种超硬新型钛-金合金，能够取代目前应用于人工膝关节和髋关节的钛金属材料，新型超硬合金硬度为为目前钛金属的4倍。

而且无毒，更耐磨损且能够用于长期医疗植入。

莱斯大学物理教授Emilia Morosan在一次从非磁性元素中提炼磁性材料的试验中意外得到了配方，将钛与黄金以1比1的比例混合，团队中部分成员尝试将之磨成粉末状，以便于放置在X光下观察其成分，结构和纯度。

团队发现得到的钛-金混合物很难被物理碾磨，团队甚至采用了钻石切割器具，仍旧无法碾磨新型钛-金混合物。

团队测出了这种混合物的硬度，同时他们测出了这种混合物中最坚硬的部分是一种在高温下形成的钛-金比例为3 ：1的合金。

它在高温下能够以近乎纯晶体的合金状态存在，硬度是钛的4倍。

尽管这种新合金并非新发现，但该小组是首个观察到如此惊人特性。

随后他们对合金的制程进行了进一步优化，得到了生物排斥性小，磨损较少的新型合金。

（中国有色金属报）。

纳米二氧化钛增韧补强3D打印光固化树脂

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利用功
化ꎬ 故对光的透过率要求不高ꎮ 但ＵＶ￣３Ｄ打印技术
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ＳＬＡ３Ｄ打印机: Ｍｏａｉꎬ 香港ＰｅｏｐｏｌｙＭｏａｉ公司ꎻ
傅里叶红外光谱仪: Ｔｅｎｓｏｒ－ＩＩꎬ 德国博鲁克公司ꎻ
场发射扫描电子显微镜: Ｓ－４８００ꎬ 日本日立公司ꎻ
热重分析仪: ＴＧＡ－６０１ꎬ ＭＥＴＴＬＥＲＴＯＬＥＤＯꎻ 橡胶
采用ＴＧＡ / ＤＳＣ分析仪ꎬ 研究不同含量改性二氧
化钛的添加量对３Ｄ打印光固化树脂热性能的影响ꎮ
测试条件: 流动速度为８０ ~ １００ｍＬ / ｍｉｎ的氮气氛
发展有限公司ꎮ
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１３１纳米ＴｉＯ２粉末的表面改性
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Titanium Dioxide Nanomaterials Synthesis, Properties, Modifications, and

Titanium Dioxide Nanomaterials:Synthesis,Properties,Modifications,andApplicationsXiaobo Chen*and Samuel S.Mao†Lawrence Berkeley National Laboratory,and University of California,Berkeley,California94720Received March27,2006Contents1.Introduction28912.Synthetic Methods for TiO2Nanostructures28922.1.Sol−Gel Method28922.2.Micelle and Inverse Micelle Methods28952.3.Sol Method28962.4.Hydrothermal Method28982.5.Solvothermal Method29012.6.Direct Oxidation Method29022.7.Chemical Vapor Deposition29032.8.Physical Vapor Deposition29042.9.Electrodeposition29042.10.Sonochemical Method29042.11.Microwave Method29042.12.TiO2Mesoporous/Nanoporous Materials29052.13.TiO2Aerogels29062.14.TiO2Opal and Photonic Materials29072.15.Preparation of TiO2Nanosheets29083.Properties of TiO2Nanomaterials29093.1.Structural Properties of TiO2Nanomaterials29093.2.Thermodynamic Properties of TiO2Nanomaterials29113.3.X-ray Diffraction Properties of TiO2Nanomaterials29123.4.Raman Vibration Properties of TiO2Nanomaterials29123.5.Electronic Properties of TiO2Nanomaterials29133.6.Optical Properties of TiO2Nanomaterials29153.7.Photon-Induced Electron and Hole Propertiesof TiO2Nanomaterials29184.Modifications of TiO2Nanomaterials29204.1.Bulk Chemical Modification:Doping29214.1.1.Synthesis of Doped TiO2Nanomaterials29214.1.2.Properties of Doped TiO2Nanomaterials29214.2.Surface Chemical Modifications29264.2.1.Inorganic Sensitization29265.Applications of TiO2Nanomaterials29295.1.Photocatalytic Applications29295.1.1.Pure TiO2Nanomaterials:FirstGeneration29305.1.2.Metal-Doped TiO2Nanomaterials:Second Generation29305.1.3.Nonmetal-Doped TiO2Nanomaterials:Third Generation 29315.2.Photovoltaic Applications29325.2.1.The TiO2Nanocrystalline Electrode inDSSCs29325.2.2.Metal/Semiconductor Junction SchottkyDiode Solar Cell29385.2.3.Doped TiO2Nanomaterials-Based SolarCell29385.3.Photocatalytic Water Splitting29395.3.1.Fundamentals of Photocatalytic WaterSplitting2939e of Reversible Redox Mediators2939e of TiO2Nanotubes29405.3.4.Water Splitting under Visible Light29415.3.5.Coupled/Composite Water-SplittingSystem29425.4.Electrochromic Devices29425.4.1.Fundamentals of Electrochromic Devices29435.4.2.Electrochromophore for an ElectrochromicDevice29435.4.3.Counterelectrode for an ElectrochromicDevice29445.4.4.Photoelectrochromic Devices29455.5.Hydrogen Storage29455.6.Sensing Applications29476.Summary29487.Acknowledgment29498.References29491.IntroductionSince its commercial production in the early twentiethcentury,titanium dioxide(TiO2)has been widely used as apigment1and in sunscreens,2,3paints,4ointments,toothpaste,5etc.In1972,Fujishima and Honda discovered the phenom-enon of photocatalytic splitting of water on a TiO2electrodeunder ultraviolet(UV)light.6-8Since then,enormous effortshave been devoted to the research of TiO2material,whichhas led to many promising applications in areas ranging fromphotovoltaics and photocatalysis to photo-/electrochromicsand sensors.9-12These applications can be roughly dividedinto“energy”and“environmental”categories,many of whichdepend not only on the properties of the TiO2material itselfbut also on the modifications of the TiO2material host(e.g.,with inorganic and organic dyes)and on the interactions ofTiO2materials with the environment.An exponential growth of research activities has been seenin nanoscience and nanotechnology in the past decades.13-17New physical and chemical properties emerge when the sizeof the material becomes smaller and smaller,and down to*Corresponding author.E-mail:XChen3@.†E-mail:SSMao@.2891 Chem.Rev.2007,107,2891−295910.1021/cr0500535CCC:$65.00©2007American Chemical SocietyPublished on Web06/23/2007the nanometer scale.Properties also vary as the shapes of the shrinking nanomaterials change.Many excellent reviews and reports on the preparation and properties of nanomaterials have been published recently.6-44Among the unique proper-ties of nanomaterials,the movement of electrons and holes in semiconductor nanomaterials is primarily governed by the well-known quantum confinement,and the transport proper-ties related to phonons and photons are largely affected by the size and geometry of the materials.13-16The specific surface area and surface-to-volume ratio increase dramati-cally as the size of a material decreases.13,21The high surface area brought about by small particle size is beneficial to many TiO 2-based devices,as it facilitates reaction/interaction between the devices and the interacting media,which mainly occurs on the surface or at the interface and strongly depends on the surface area of the material.Thus,the performance of TiO 2-based devices is largely influenced by the sizes of the TiO 2building units,apparently at the nanometer scale.As the most promising photocatalyst,7,11,12,33TiO 2mate-rials are expected to play an important role in helping solvemany serious environmental and pollution challenges.TiO 2also bears tremendous hope in helping ease the energy crisis through effective utilization of solar energy based on photovoltaic and water-splitting devices.9,31,32As continued breakthroughs have been made in the preparation,modifica-tion,and applications of TiO 2nanomaterials in recent years,especially after a series of great reviews of the subject in the 1990s.7,8,10-12,33,45we believe that a new and compre-hensive review of TiO 2nanomaterials would further promote TiO 2-based research and development efforts to tackle the environmental and energy challenges we are currently facing.Here,we focus on recent progress in the synthesis,properties,modifications,and applications of TiO 2nanomaterials.The syntheses of TiO 2nanomaterials,including nanoparticles,nanorods,nanowires,and nanotubes are primarily categorized with the preparation method.The preparations of mesopo-rous/nanoporous TiO 2,TiO 2aerogels,opals,and photonic materials are summarized separately.In reviewing nanoma-terial synthesis,we present a typical procedure and repre-sentative transmission or scanning electron microscopy images to give a direct impression of how these nanomate-rials are obtained and how they normally appear.For detailed instructions on each synthesis,the readers are referred to the corresponding literature.The structural,thermal,electronic,and optical properties of TiO 2nanomaterials are reviewed in the second section.As the size,shape,and crystal structure of TiO 2nanomate-rials vary,not only does surface stability change but also the transitions between different phases of TiO 2under pressure or heat become size dependent.The dependence of X-ray diffraction patterns and Raman vibrational spectra on the size of TiO 2nanomaterials is also summarized,as they could help to determine the size to some extent,although correlation of the spectra with the size of TiO 2nanomaterials is not straightforward.The review of modifications of TiO 2nanomaterials is mainly limited to the research related to the modifications of the optical properties of TiO 2nanoma-terials,since many applications of TiO 2nanomaterials are closely related to their optical properties.TiO 2nanomaterials normally are transparent in the visible light region.By doping or sensitization,it is possible to improve the optical sensitiv-ity and activity of TiO 2nanomaterials in the visible light region.Environmental (photocatalysis and sensing)and energy (photovoltaics,water splitting,photo-/electrochromics,and hydrogen storage)applications are reviewed with an emphasis on clean and sustainable energy,since the increas-ing energy demand and environmental pollution create a pressing need for clean and sustainable energy solutions.The fundamentals and working principles of the TiO 2nanoma-terials-based devices are discussed to facilitate the under-standing and further improvement of current and practical TiO 2nanotechnology.2.Synthetic Methods for TiO 2Nanostructures2.1.Sol −Gel MethodThe sol -gel method is a versatile process used in making various ceramic materials.46-50In a typical sol -gel process,a colloidal suspension,or a sol,is formed from the hydrolysis and polymerization reactions of the precursors,which are usually inorganic metal salts or metal organic compounds such as metal plete polymerization and loss of solvent leads to the transition from the liquid sol into a solid gel phase.Thin films can be produced on a pieceofDr.Xiaobo Chen is a research engineer at The University of California at Berkeley and a Lawrence Berkeley National Laboratory scientist.He obtained his Ph.D.Degree in Chemistry from Case Western Reserve University.His research interests include photocatalysis,photovoltaics,hydrogen storage,fuel cells,environmental pollution control,and the related materials and devicesdevelopment.Dr.Samuel S.Mao is a career staff scientist at Lawrence Berkeley National Laboratory and an adjunct faculty at The University of California at Berkeley.He obtained his Ph.D.degree in Engineering from The University of California at Berkeley in 2000.His current research involves the development of nanostructured materials and devices,as well as ultrafast laser technologies.Dr.Mao is the team leader of a high throughput materials processing program supported by the U.S.Department of Ener-gy.2892Chemical Reviews,2007,Vol.107,No.7Chen and Maosubstrate by spin-coating or dip-coating.A wet gel will form when the sol is cast into a mold,and the wet gel is converted into a dense ceramic with further drying and heat treatment.A highly porous and extremely low-density material called an aerogel is obtained if the solvent in a wet gel is removed under a supercritical condition.Ceramic fibers can be drawn from the sol when the viscosity of a sol is adjusted into a proper viscosity range.Ultrafine and uniform ceramic powders are formed by precipitation,spray pyrolysis,or emulsion techniques.Under proper conditions,nanomaterials can be obtained.TiO2nanomaterials have been synthesized with the sol-gel method from hydrolysis of a titanium precusor.51-78This process normally proceeds via an acid-catalyzed hydrolysis step of titanium(IV)alkoxide followed by condensa-tion.51,63,66,79-91The development of Ti-O-Ti chains is favored with low content of water,low hydrolysis rates,and excess titanium alkoxide in the reaction mixture.Three-dimensional polymeric skeletons with close packing result from the development of Ti-O-Ti chains.The formation of Ti(OH)4is favored with high hydrolysis rates for a medium amount of water.The presence of a large quantity of Ti-OH and insufficient development of three-dimensional polymeric skeletons lead to loosely packed first-order particles.Polymeric Ti-O-Ti chains are developed in the presence of a large excess of water.Closely packed first-order particles are yielded via a three-dimensionally devel-oped gel skeleton.51,63,66,79-91From the study on the growth kinetics of TiO2nanoparticles in aqueous solution using titanium tetraisopropoxide(TTIP)as precursor,it is found that the rate constant for coarsening increases with temper-ature due to the temperature dependence of the viscosity of the solution and the equilibrium solubility of TiO2.63Second-ary particles are formed by epitaxial self-assembly of primary particles at longer times and higher temperatures,and the number of primary particles per secondary particle increases with time.The average TiO2nanoparticle radius increases linearly with time,in agreement with the Lifshitz-Slyozov-Wagner model for coarsening.63Highly crystalline anatase TiO2nanoparticles with different sizes and shapes could be obtained with the polycondensation of titanium alkoxide in the presence of tetramethylammonium hydroxide.52,62In a typical procedure,titanium alkoxide is added to the base at2°C in alcoholic solvents in a three-neck flask and is heated at50-60°C for13days or at90-100°C for6h.A secondary treatment involving autoclave heating at175and200°C is performed to improve the crystallinity of the TiO2nanoparticles.Representative TEM images are shown in Figure1from the study of Chemseddine et al.52A series of thorough studies have been conducted by Sugimoto et ing the sol-gel method on the formation of TiO2nanoparticles of different sizes and shapes by tuning the reaction parameters.67-71Typically,a stock solution of a0.50M Ti source is prepared by mixing TTIP with triethanolamine(TEOA)([TTIP]/[TEOA])1:2),followed by addition of water.The stock solution is diluted with a shape controller solution and then aged at100°C for1day and at140°C for3days.The pH of the solution can be tuned by adding HClO4or NaOH solution.Amines are used as the shape controllers of the TiO2nanomaterials and act as surfactants.These amines include TEOA,diethylenetri-amine,ethylenediamine,trimethylenediamine,and triethyl-enetetramine.The morphology of the TiO2nanoparticles changes from cuboidal to ellipsoidal at pH above11with TEOA.The TiO2nanoparticle shape evolves into ellipsoidal above pH9.5with diethylenetriamine with a higher aspect ratio than that with TEOA.Figure2shows representative TEM images of the TiO2nanoparticles under different initial pH conditions with the shape control of TEOA at[TEOA]/ [TIPO])2.0.Secondary amines,such as diethylamine,and tertiary amines,such as trimethylamine and triethylamine, act as complexing agents of Ti(IV)ions to promote the growth of ellipsoidal particles with lower aspect ratios.The shape of the TiO2nanoparticle can also be tuned from round-cornered cubes to sharp-edged cubes with sodium oleate and sodium stearate.70The shape control is attributed to the tuning of the growth rate of the different crystal planes of TiO2 nanoparticles by the specific adsorption of shape controllers to these planes under different pH conditions.70A prolonged heating time below100°C for the as-prepared gel can be used to avoid the agglomeration of the TiO2nano-particles during the crystallization process.58,72By heating amorphous TiO2in air,large quantities of single-phase ana-tase TiO2nanoparticles with average particle sizes between 7and50nm can be obtained,as reported by Zhang and Banfield.73-77Much effort has been exerted to achieve highly crystallized and narrowly dispersed TiO2nanoparticles using the sol-gel method with other modifications,such as a semicontinuous reaction method by Znaidi et al.78and a two-stage mixed method and a continuous reaction method by Kim et al.53,54By a combination of the sol-gel method and an anodic alumina membrane(AAM)template,TiO2nanorods have been successfully synthesized by dipping porous AAMs into a boiled TiO2sol followed by drying and heating processes.92,93In a typical experiment,a TiO2sol solution is prepared by mixing TTIP dissolved in ethanol with a solution containing water,acetyl acetone,and ethanol.An AAM is immersed into the sol solution for10min after being boiled in ethanol;then it is dried in air and calcined at400°C for 10h.The AAM template is removed in a10wt%H3PO4 aqueous solution.The calcination temperature can be used to control the crystal phase of the TiO2nanorods.At low temperature,anatase nanorods can be obtained,while at high temperature rutile nanorods can be obtained.The pore size of the AAM template can be used to control the size of these TiO2nanorods,which typically range from100to300 nm in diameter and several micrometers in length.Appar-ently,the size distribution of the final TiO2nanorods is largely controlled by the size distribution of the pores of the AAM template.In order to obtain smaller and mono-sized TiO2nanorods,it is necessary to fabricate high-quality AAM templates.Figure3shows a typical TEM for TiO2 nanorods fabricated with this method.Normally,the TiO2 nanorods are composed of small TiO2nanoparticles or nanograins.By electrophoretic deposition of TiO2colloidal suspensions into the pores of an AAM,ordered TiO2nanowire arrays can be obtained.94In a typical procedure,TTIP is dissolved in ethanol at room temperature,and glacial acetic acid mixed with deionized water and ethanol is added under pH)2-3 with nitric acid.Platinum is used as the anode,and an AAM with an Au substrate attached to Cu foil is used as the cathode.A TiO2sol is deposited into the pores of the AMM under a voltage of2-5V and annealed at500°C for24h. After dissolving the AAM template in a5wt%NaOH solution,isolated TiO2nanowires are obtained.In order toTitanium Dioxide Nanomaterials Chemical Reviews,2007,Vol.107,No.72893fabricate TiO 2nanowires instead of nanorods,an AAM with long pores is a must.TiO 2nanotubes can also be obtained using the sol -gel method by templating with an AAM 95-98and other organic compounds.99,100For example,when an AAM is used as the template,a thin layer of TiO 2sol on the wall of the pores of the AAM is first prepared by sucking TiO 2sol into the pores of the AAM and removing it under vacuum;TiO 2nanowires are obtained after the sol is fully developed and the AAM is removed.In the procedure by Lee and co-workers,96a TTIP solution was prepared by mixing TTIP with 2-propanol and 2,4-pentanedione.After the AAM was dipped intothisFigure 1.TEM images of TiO 2nanoparticles prepared by hydrolysis of Ti(OR)4in the presence of tetramethylammonium hydroxide.Reprinted with permission from Chemseddine,A.;Moritz,T.Eur.J.Inorg.Chem.1999,235.Copyright 1999Wiley-VCH.Figure 2.TEM images of uniform anatase TiO 2nanoparticles.Reprinted from Sugimoto,T.;Zhou,X.;Muramatsu,A.J.Colloid Interface Sci.2003,259,53,Copyright 2003,with permission from Elsevier.2894Chemical Reviews,2007,Vol.107,No.7Chen and Maosolution,it was removed from the solution and placed under vacuum until the entire volume of the solution was pulled through the AAM.The AAM was hydrolyzed by water vapor over a HCl solution for 24h,air-dried at room temperature,and then calcined in a furnace at 673K for 2h and cooled to room temperature with a temperature ramp of 2°C/h.Pure TiO 2nanotubes were obtained after the AAM was dissolved in a 6M NaOH solution for several minutes.96Alternatively,TiO 2nanotubes could be obtained by coating the AAM membranes at 60°C for a certain period of time (12-48h)with dilute TiF 4under pH )2.1and removing the AAM after TiO 2nanotubes were fully developed.97Figure 4shows a typical SEM image of the TiO 2nanotube array from the AAM template.97In another scheme,a ZnO nanorod array on a glass substrate can be used as a template to fabricate TiO 2nanotubes with the sol -gel method.101Briefly,TiO 2sol isdeposited on a ZnO nanorod template by dip-coating with a slow withdrawing speed,then dried at 100°C for 10min,and heated at 550°C for 1h in air to obtain ZnO/TiO 2nanorod arrays.The ZnO nanorod template is etched-up by immersing the ZnO/TiO 2nanorod arrays in a dilute hydro-chloric acid aqueous solution to obtain TiO 2nanotube arrays.Figure 5shows a typical SEM image of the TiO 2nanotube array with the ZnO nanorod array template.The TiO 2nanotubes inherit the uniform hexagonal cross-sectional shape and the length of 1.5µm and inner diameter of 100-120nm of the ZnO nanorod template.As the concentration of the TiO 2sol is constant,well-aligned TiO 2nanotube arrays can only be obtained from an optimal dip-coating cycle number in the range of 2-3cycles.A dense porous TiO 2thick film with holes is obtained instead if the dip-coating number further increases.The heating rate is critical to the formation of TiO 2nanotube arrays.When the heating rate is extra rapid,e.g.,above 6°C min -1,the TiO 2coat will easily crack and flake off from the ZnO nanorods due to great tensile stress between the TiO 2coat and the ZnO template,and a TiO 2film with loose,porous nanostructure is obtained.2.2.Micelle and Inverse Micelle MethodsAggregates of surfactant molecules dispersed in a liquid colloid are called micelles when the surfactant concentration exceeds the critical micelle concentration (CMC).The CMC is the concentration of surfactants in free solution in equilibrium with surfactants in aggregated form.In micelles,the hydrophobic hydrocarbon chains of the surfactants are oriented toward the interior of the micelle,and the hydro-philic groups of the surfactants are oriented toward the surrounding aqueous medium.The concentration of the lipid present in solution determines the self-organization of the molecules of surfactants and lipids.The lipids form a single layer on the liquid surface and are dispersed in solution below the CMC.The lipids organize in spherical micelles at the first CMC (CMC-I),into elongated pipes at the second CMC (CMC-II),and into stacked lamellae of pipes at the lamellar point (LM or CMC-III).The CMC depends on the chemical composition,mainly on the ratio of the head area and the tail length.Reverse micelles are formed in nonaqueous media,and the hydrophilic headgroups are directed toward the core of the micelles while the hydrophobic groupsareFigure 3.TEM image of anatase nanorods and a single nanorod composed of small TiO 2nanoparticles or nanograins (inset).Reprinted from Miao,L.;Tanemura,S.;Toh,S.;Kaneko,K.;Tanemura,M.J.Cryst.Growth 2004,264,246,Copyright 2004,with permission fromElsevier.Figure 4.SEM image of TiO 2nanotubes prepared from the AAO template.Reprinted with permission from Liu,S.M.;Gan,L.M.;Liu,L.H.;Zhang,W.D.;Zeng,H.C.Chem.Mater.2002,14,1391.Copyright 2002American ChemicalSociety.Figure 5.SEM of a TiO 2nanotube array;the inset shows the ZnO nanorod array template.Reprinted with permission from Qiu,J.J.;Yu,W.D.;Gao,X.D.;Li,X.M.Nanotechnology 2006,17,4695.Copyright 2006IOP Publishing Ltd.Titanium Dioxide Nanomaterials Chemical Reviews,2007,Vol.107,No.72895directed outward toward the nonaqueous media.There is no obvious CMC for reverse micelles,because the number of aggregates is usually small and they are not sensitive to the surfactant concentration.Micelles are often globular and roughly spherical in shape,but ellipsoids,cylinders,and bilayers are also possible.The shape of a micelle is a function of the molecular geometry of its surfactant molecules and solution conditions such as surfactant concentration,tem-perature,pH,and ionic strength.Micelles and inverse micelles are commonly employed to synthesize TiO2nanomaterials.102-110A statistical experi-mental design method was conducted by Kim et al.to optimize experimental conditions for the preparation of TiO2 nanoparticles.103The values of H2O/surfactant,H2O/titanium precursor,ammonia concentration,feed rate,and reaction temperature were significant parameters in controlling TiO2 nanoparticle size and size distribution.Amorphous TiO2 nanoparticles with diameters of10-20nm were synthesized and converted to the anatase phase at600°C and to the more thermodynamically stable rutile phase at900°C.Li et al. developed TiO2nanoparticles with the chemical reactions between TiCl4solution and ammonia in a reversed micro-emulsion system consisting of cyclohexane,poly(oxyethyl-ene)5nonyle phenol ether,and poly(oxyethylene)9nonyle phenol ether.104The produced amorphous TiO2nanoparticles transformed into anatase when heated at temperatures from 200to750°C and into rutile at temperatures higher than 750°C.Agglomeration and growth also occurred at elevated temperatures.Shuttle-like crystalline TiO2nanoparticles were synthesized by Zhang et al.with hydrolysis of titanium tetrabutoxide in the presence of acids(hydrochloric acid,nitric acid,sulfuric acid,and phosphoric acid)in NP-5(Igepal CO-520)-cyclohexane reverse micelles at room temperature.110The crystal structure,morphology,and particle size of the TiO2 nanoparticles were largely controlled by the reaction condi-tions,and the key factors affecting the formation of rutile at room temperature included the acidity,the type of acid used, and the microenvironment of the reverse micelles.Ag-glomeration of the particles occurred with prolonged reaction times and increasing the[H2O]/[NP-5]and[H2O]/[Ti-(OC4H9)4]ratios.When suitable acid was applied,round TiO2 nanoparticles could also be obtained.Representative TEM images of the shuttle-like and round-shaped TiO2nanopar-ticles are shown in Figure6.In the study carried out by Lim et al.,TiO2nanoparticles were prepared by the controlled hydrolysis of TTIP in reverse micelles formed in CO2with the surfactants ammonium carboxylate perfluoropolyether(PFPECOO-NH4+)(MW587)and poly(dimethyl amino ethyl methacrylate-block-1H,1H,2H,2H-perfluorooctyl meth-acrylate)(PDMAEMA-b-PFOMA).106It was found that the crystallite size prepared in the presence of reverse micelles increased as either the molar ratio of water to surfactant or the precursor to surfactant ratio increased.The TiO2nanomaterials prepared with the above micelle and reverse micelle methods normally have amorphous structure,and calcination is usually necessary in order to induce high crystallinity.However,this process usually leads to the growth and agglomeration of TiO2nanoparticles.The crystallinity of TiO2nanoparticles initially(synthesized by controlled hydrolysis of titanium alkoxide in reverse micelles in a hydrocarbon solvent)could be improved by annealing in the presence of the micelles at temperatures considerably lower than those required for the traditional calcination treatment in the solid state.108This procedure could produce crystalline TiO2nanoparticles with unchanged physical dimensions and minimal agglomeration and allows the preparation of highly crystalline TiO2nanoparticles,as shown in Figure7,from the study of Lin et al.1082.3.Sol MethodThe sol method here refers to the nonhydrolytic sol-gel processes and usually involves the reaction of titanium chloride with a variety of different oxygen donor molecules, e.g.,a metal alkoxide or an organic ether.111-119Figure6.TEM images of the shuttle-like and round-shaped(inset) TiO2nanoparticles.From:Zhang,D.,Qi,L.,Ma,J.,Cheng,H.J. Mater.Chem.2002,12,3677(/10.1039/b206996b). s Reproduced by permission of The Royal Society ofChemistry.Figure7.HRTEM images of a TiO2nanoparticle after annealing. Reprinted with permission from Lin,J.;Lin,Y.;Liu,P.;Meziani, M.J.;Allard,L.F.;Sun,Y.P.J.Am.Chem.Soc.2002,124,11514. Copyright2002American Chemical Society.TiX4+Ti(OR)4f2TiO2+4RX(1)TiX4+2ROR f TiO2+4RX(2)2896Chemical Reviews,2007,Vol.107,No.7Chen and MaoThe condensation between Ti -Cl and Ti-OR leads to the formation of Ti -O -Ti bridges.The alkoxide groups can be provided by titanium alkoxides or can be formed in situ by reaction of the titanium chloride with alcohols or ethers.In the method by Trentler and Colvin,119a metal alkoxide was rapidly injected into the hot solution of titanium halide mixed with trioctylphosphine oxide (TOPO)in heptadecane at 300°C under dry inert gas protection,and reactions were completed within 5min.For a series of alkyl substituents including methyl,ethyl,isopropyl,and tert -butyl,the reaction rate dramatically increased with greater branching of R,while average particle sizes were relatively unaffected.Variation of X yielded a clear trend in average particle size,but without a discernible trend in reaction rate.Increased nucleophilicity (or size)of the halide resulted in smaller anatase nanocrystals.Average sizes ranged from 9.2nm for TiF 4to 3.8nm for TiI 4.The amount of passivating agent (TOPO)influenced the chemistry.Reaction in pure TOPO was slower and resulted in smaller particles,while reactions without TOPO were much quicker and yielded mixtures of brookite,rutile,and anatase with average particle sizes greater than 10nm.Figure 8shows typical TEM images of TiO 2nanocrystals developed by Trentler et al.119In the method used by Niederberger and Stucky,111TiCl 4was slowly added to anhydrous benzyl alcohol under vigorous stirring at room temperature and was kept at 40-150°C for 1-21days in the reaction vessel.The precipitate was calcinated at 450°C for 5h after thoroughly washing.The reaction between TiCl 4and benzyl alcohol was found suitable for the synthesis of highly crystalline anatase phase TiO 2nanoparticles with nearly uniform size and shape at very low temperatures,such as 40°C.The particle size could be selectively adjusted in the range of 4-8nm with the appropriate thermal conditions and a proper choice of the relative amounts of benzyl alcohol and titanium tetrachloride.The particle growth depended strongly on temperature,and lowering the titanium tetrachloride concentration led to a considerable decrease of particle size.111Surfactants have been widely used in the preparation of a variety of nanoparticles with good size distribution and dispersity.15,16Adding different surfactants as capping agents,such as acetic acid and acetylacetone,into the reaction matrixcan help synthesize monodispersed TiO 2nanoparticles.120,121For example,Scolan and Sanchez found that monodisperse nonaggregated TiO 2nanoparticles in the 1-5nm range were obtained through hydrolysis of titanium butoxide in the presence of acetylacetone and p -toluenesulfonic acid at 60°C.120The resulting nanoparticle xerosols could be dispersed in water -alcohol or alcohol solutions at concentrations higher than 1M without aggregation,which is attributed to the complexation of the surface by acetylacetonato ligands and through an adsorbed hybrid organic -inorganic layer made with acetylacetone,p -toluenesulfonic acid,and wa-ter.120With the aid of surfactants,different sized and shaped TiO 2nanorods can be synthesized.122-130For example,the growth of high-aspect-ratio anatase TiO 2nanorods has been reported by Cozzoli and co-workers by controlling the hydrolysis process of TTIP in oleic acid (OA).122-126,130Typically,TTIP was added into dried OA at 80-100°C under inert gas protection (nitrogen flow)and stirred for 5min.A 0.1-2M aqueous base solution was then rapidly injected and kept at 80-100°C for 6-12h with stirring.The bases employed included organic amines,such as trimethylamino-N-oxide,trimethylamine,tetramethylammonium hydroxide,tetrabut-ylammonium hydroxyde,triethylamine,and tributylamine.In this reaction,by chemical modification of the titanium precursor with the carboxylic acid,the hydrolysis rate of titanium alkoxide was controlled.Fast (in 4-6h)crystal-lization in mild conditions was promoted with the use of suitable catalysts (tertiary amines or quaternary ammonium hydroxides).A kinetically overdriven growth mechanism led to the growth of TiO 2nanorods instead of nanoparticles.123Typical TEM images of the TiO 2nanorods are shown in Figure 9.123Recently,Joo et al.127and Zhang et al.129reported similar procedures in obtaining TiO 2nanorods without the use of catalyst.Briefly,a mixture of TTIP and OA was used to generate OA complexes of titanium at 80°C in1-octadecene.Figure 8.TEM image of TiO 2nanoparticles derived from reaction of TiCl 4and TTIP in TOPO/heptadecane at 300°C.The inset shows a HRTEM image of a single particle.Reprinted with permission from Trentler,T.J.;Denler,T.E.;Bertone,J.F.;Agrawal,A.;Colvin,V.L.J.Am.Chem.Soc.1999,121,1613.Copyright 1999American ChemicalSociety.Figure 9.TEM of TiO 2nanorods.The inset shows a HRTEM of a TiO 2nanorod.Reprinted with permission from Cozzoli,P.D.;Kornowski,A.;Weller,H.J.Am.Chem.Soc.2003,125,14539.Copyright 2003American Chemical Society.Titanium Dioxide Nanomaterials Chemical Reviews,2007,Vol.107,No.72897。

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S Supporting Information *
CONTENTS
1. Introduction 2. Basic Properties of TiO2 Semiconductor Photocatalysts 2.1. Photocatalytic Reactions on TiO2 2.2. Diﬀerent Phase Structures of TiO2 3. Hydrogen Generation on TiO2-Based Photocatalysts 3.1. Light Harvesting 3.1.1. Bandgap Engineering 3.1.2. Surface Sensitization 3.2. Photogenerated Charge Separation 3.2.1. Fabrication of Heterojunction 3.2.2. Fabrication of Phase Junction 3.2.3. Fabrication of Schottky Junction 3.3. Loading Cocatalysts on TiO2 3.3.1. Metal Cocatalysts 3.3.2. Metal Oxide/Hydroxide/Sulﬁde Cocatalysts 3.3.3. Molecular Complex Cocatalysts 3.4. From Overall Water Splitting to Biomass Reforming 3.4.1. Photocatalytic Overall Water Splitting on TiO2-Based Photocatalysts 3.4.2. Hydrogen Generation from Biomass and Their Derivatives on TiO2-Based Photocatalysts 3.5. Photocatalytic Reaction Mechanisms on TiO2-Based Photocatalysts 3.5.1. Photoluminescence Study on Carrier Dynamics of TiO2 3.5.2. Time-Resolved Spectroscopic Study on the Eﬀect of Modiﬁcations on TiO2 3.5.3. Role of Cocatalyst Pt on TiO2
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Received: January 4, 2014 Published: August 7, 2014
/10.1021/cr500008u | Chem. Rev. 2014, 114, 9987−10043
Chemical Reviews
5. Conclusions, Perspectives, and Remarks Associated Content Supporting Information Author Information Corresponding Authors Author Contributions Notes Biographies Acknowledgments References 10030 10031 10031 10031 10031 10031 10031 10032 10033 10033
†
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457 Zhongshan Road, Dalian 116023, China ‡ Department of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States
© 2014 American Chemical Society
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3.5.4. Mechanistic Studies on Photocatalytic Reactions of Water or Methanol for Hydrogen Production 3.6. Isotope Labeling Dynamic and Kinetic Studies of Photocatalytic Reactions on the Surface of TiO2 3.6.1. Oxidation Reactions on the Surface of TiO2 3.6.2. Hydrogen Production Reactions on the Surface of TiO2 4. Photoreduction of CO2 to Solar Fuels on TiO2Based Photocatalysts 4.1. Mixed-Phase TiO 2 Composites for CO 2 Photoreduction 4.2. Crystal Facet Engineering of TiO2 for CO2 Photoreduction 4.3. TiO2-Based Nanocomposite Photocatalysts for CO2 Photoreduction 4.3.1. Metal Loaded TiO2-Based Nanocomposite Photocatalysts 4.3.2. Metal Oxide Loaded TiO2-Based Nanocomposite Photocatalysts 4.3.3. TiO2-Based Multinary Nanocomposite Photocatalysts 4.4. TiO2-Based Photocatalysts on Various Supports for CO2 Photoreduction 4.4.1. Silica Materials as Supports 4.4.2. Carbon-Based Materials as Supports 4.5. Visible Light-Responsive TiO2-Based Photocatalysts and Photocatalytic Systems for CO2 Photoreduction 4.5.1. Anion Doped TiO2-Based Photocatalysts 4.5.2. Dyes and Molecular Complexes-Sensitized TiO2-Based Photocatalysts 4.5.3. Quantum Dots-Sensitized TiO2-Based Photocatalysts 4.6. Impact of Reaction Conditions on CO2 Photoreduction 4.7. Mechanism of CO2 Photoreduction on TiO2Based Photocatalysts
Special Issue: 2014 Titanium Dioxide Nanomaterials
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Review
1. INTRODUCTION Nowadays, with the rapid depletion of fossil fuels (coal, natural gas, and petroleum oil), the development of renewable energies based on suﬃcient energy sources with sustainable supply for the long-term in a large quantity is in high demand. Ever increasing attention has been paid to exploring novel methods for developing renewable energy technologies. Conversion of solar energy into chemical energy in the form of so-called “solar fuels”, such as H2, methanol, methane, etc., is considered one of the most perspective strategies to solve the energy and environmental problems in the future. H2 is an excellent energy carrier for the development of lowcarbon emission economy. First, it has high caloriﬁc value per mass unit, which is triple that of gasoline and quadruple that of natural gas. Moreover, no greenhouse gases are produced during the combustion process of H2. Therefore, storage of solar energy in the form of H2 is proposed to be one of the most ideal routes for developing clean and sustainable energy in the future. Second, hydrogen is the most abundant element that can be obtained from a broad range of substances. Third, H2 is also an important chemical reagent in the chemical industry. To develop hydrogen economy, extensive research has been carried out on photocatalytic or photoelectrochemical (PEC) splitting of water into H2 and O2 since the ﬁrst report of the photoelectrochemical water splitting reaction on TiO2 electrode by Fujishima and Honda et al.1 Another meaningful reaction for solar-to-chemical energy conversion is photocatalytic or photoelectrochemical reduction of CO2 to chemical fuels. According to recent reports, global CO2 emission currently is ca. 37 Gt with 30.4 Gt related to the utilization of fossil fuels and predicted to increase up to 36−43 Gt by 2035.2 The atmospheric level of CO2 rose from 270 ppm in the preindustrial era3 to nearly 395 ppm in 2012,4 which far exceeds its natural ﬂuctuation (d = 180−300 ppm) over the past millions of years.5 With the greenhouse eﬀect of CO2 causing serious climate and environmental problems, CO2 emission is now a great global concern. One of the ideal solutions to solve the CO2 problem is to develop solar fuels by artiﬁcial photosynthesis, that is, storage of solar energy in chemical forms by photoreduction of CO2 to high-energy compounds such as carbon monoxide, methanol or methane, or even high-carbon based compounds. Such kind of artiﬁcial photosynthesis for solar fuels generation is a carbon neutral cycle process because no additional carbon source other than atmosphere CO2 is used. As one of the earliest studied n-type semiconductor photocatalysts, TiO2 has been widely used in environmental puriﬁcation,6 self-cleaning, H2 production, photosynthesis, CO2 reduction,7 organic synthesis,8 solar cells, etc.9 Being cheap, stable, nontoxic, and environmentally friendly, TiO2 is an idea model of semiconductor photocatalyst to investigate. There9988