固溶体理论

Solid Solution of GaN and ZnO as a Stable Photocatalyst for Overall Water Splitting under Visible Light†
• Large-scale hydrogen production from water using only solar energy is an ultimate goal for the supply of clean, recyclable energy, and several reactions and schemes have been proposed. Overall water splitting using a particulate photocatalyst is one attractive solution with a wide range of applications. A number of photocatalysts have been proposed, and some have achieved high quantum efficiencies. Unfortunately, most of these photocatalysts consist of metal oxides and work only in the ultraviolet (UV) region. To effectively utilize solar energy, it is necessary to develop a material that will function under visible light. This paper reviews the recent development of such a photocatalyst, specifically focusing on efforts by the authors’ group to prepare a solid solution of GaN and ZnO. This new material is capable of splitting water into hydrogen and oxygen under visible light (λ > 400 nm) with good reproducibility.
Hume-Rothery rules
• For two metallic atoms to form solid solutions, the two metals must be: 1) Less than about 15% difference in atomic radii. 2) The same crystal structure 3) Similar electronegatives. 4) The same valence
下图
• Dependence of the rates of H2 and O2 evolution by 5 wt % RuO2-loaded (Ga1−xZnx)(N1−xOx) (entry 3, see Table 1) on the cutoff wavelength of the incident light. Catalyst (0.3 g); an aqueous solution adjusted to pH 3 by H2SO4 (200 mL); light source, xenon lamp (300 W) attached with a cutoff filter; top-irradiation-type Pyrex reaction vessel.
ห้องสมุดไป่ตู้电池材料
• LiCoO2 • LiMn2O4 • LiFePO4
Al2O3 on In2O3
• The growth of Al2O3 onto Sn-doped In2O3 (ITO) by atomic layer deposition (ALD) was studied in situ using X-ray photoelectron spectroscopy. Significant diffusion of oxygen from the substrate destroys the self-terminated monolayer adsorption of the metal precursor and results in a nominal initial growth per cycle of >1 nm. The observed mechanism precludes the preparation of monolayer thick Al2O3 films on ITO substrates by ALD. The energy band alignment at the ITO/Al2O3 interface is significantly different from that obtained when magnetron sputtering is used for the deposition of Al2O3 onto ITO [Gassenbauer et al., Phys. Chem. Chem. Phys.2009, 11, 3049]. The difference is attributed to a pinning of the Fermi level in the ALD-Al2O3 layer close to midgap, which is attributed to the incorporation of hydrogen in the film during growth.
金属半径,pm
• Li 152, Be 115, Na 186, Mg 16v 132, Cr 125, Mn 112, Fe 124, 0, Al 143, Si 117, K 231, Ca 197, Sc 160, Ti 147, Co 125, Ni 125, Cu 128, Zn 133, Ga 135, Ge 122, Y 181, Zr 158, Nb 143, Mo 136, Pd 137, Ag 144, Sn 158, Cs 265, Ba 217, W 137, Pt 138, Au 144, Pb 175,
作业
• 举例说明掺杂对材料的结构和性能的影响。
William Hume-Rothery
• 1899-1968 • British metallurgist • Major contributions to theoretical and experimental metallurgy as well as metallurgical eucation.
置换固溶体
• 同价置换固溶体 • 异价置换固溶体
变价阳离子
• • • • • NiO CoO FeO Cu2O MnO2
离子补偿机理
• 高价阳离子取代低价阳离子
阳离子空位 阴离子间隙
• 用低价阳离子取代高价阳离子
阴离子空位
阳离子间隙
异价掺杂举例
• • • • • • • 1 用CaCl2参杂NaCl 2 用Li2O掺杂NiO 3 用TiO2掺杂Fe2O3 4 用SrO掺杂LaMnO3 5 用CaO掺杂ZrO2 6 用Y2O3参杂ZrO2 7 用Na2O参杂Al2O3
计算含15%（摩尔比）CaO的ZrO2固溶体 Zr0.85Ca0.15O1.85的密度。已知晶格常数 =0.5131nm.
因是氧空位缺陷，每单胞所含原子重： Ca: 0.15 × 4 × 40.08=24.048/NA Zr: 0.85 × 4 × 91.22=310.148/NA O: 1.85 × 4 × 16=118.40/NA 所以，D=(24.048+310.148+118.40)/6.023 × 1023 × (0.5131 × 10-7)3=5.57g/cm3
图标
• chematic illustration of overall water splitting on a heterogeneous photocatalyst.
GaN-ZnO
下图
• Typical time course of overall water splitting under UV and visible irradiation (λ > 300 nm) on 3.5 wt % RuO2-loaded (Ga1−xZnx)(N1−xOx) (entry 3, see Table 1). Catalyst (0.3 g); reactant solution, pure water (390 mL); light source, high-pressure mercury lamp (450 W); innerirradiation-type Pyrex reaction vessel.
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Layered Oxide Material for LithiumIon Batteries: Evidence of a Solid Solution Li[Li Ni Mn ]O , which is a cathode material for Li-ion
0.2 0.2 0.6 2
batteries with enhanced capacity, has been examined, for the first time, with a combination of aberration-corrected scanning transmission electron microscopy (STEM), STEM computer simulations, and diffraction scanning transmission electron microscopy (D-STEM). These techniques, in combination with X-ray diffraction (XRD) and conventional electron diffraction (ED), indicate that this material is composed of a solid solution with C2/m monoclinic symmetry and multiple planar defects. In addition, we show that XRD and ED alone can give misleading information and cannot resolve the structure of these materials without the additional use of the aforementioned techniques.
固溶体理论
2012-12-3
Ruby
固溶体概述
• 定义：在多组元物质中，以某一组元为溶剂， 其它组元为溶质，形成与溶剂组元相同的晶体 结构、晶格常数略有变化的固相叫固溶体。 • 特点：1）溶质原子在溶剂晶格中有两种存在 位置：置换固溶体和间隙固溶体。 2）溶质原 子在溶剂晶格中的浓度可以是有限的，但也可 以是无限的。 当固溶体的化学组成在一定范 围内变化，其性能随成分连续变化。间隙固溶 体必定是有限固溶体。 3）溶质原子在溶剂晶 格中位置的分布可以是无序的，也可以是有序 的。