材料学院毕业设计Bi2Te3的合成与形貌控制
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IItal Te, Bi4Te3 ； and the adding amount of changes in EDTA will lead to the generation of impurity in the sample-Te. And according to the SEM
1.3
热电材料的研究现状............................................................................9 1.3.1 1.3.2 热电材料的研究现状.................................................................10 制备 Bi2Te3 纳米材料的方法......................................................11
样品的测试..........................................................................................16 2.5.1 2.5.2 XRD 分析简介............................................................................16 SEM 简介....................................................................................17
i
山东科技大学学士学位论文
Abstract
3、 实验结果分析............................................................................................19
3.1 3.2 实验反应机理......................................................................................19 实验结果分析软件..............................................................................20 3.2.1 3.2.2 3.3 Jade 软件.....................................................................................20 Origin 软件..................................................................................22
本课题采用循环环流法来制备出075mmol的纳米bi2te3试样先称量一定量的氢氧化钠加入250ml的三颈烧瓶中再向烧瓶中加入95ml的蒸馏水再称量02871g的te粉作为te源加入三颈烧瓶中将此混合物加热到100左右然后再加入04730g的bicl3作为bi源最后加入03g的nahb4作为还原剂和一定量的edta作为络合剂需要注意的是每加入一份药品都要用蒸馏水冲洗掉三口烧瓶内壁上的残留
关键词：热电材料；Bi2Te3；循环环流法；NaOH；EDTA
I
山东科技大学学士学位论文
Abstract
Abstract
Thermoelectric material is a kind of functional material, it can come true the direct conversion between electric energy and heat energy , which has a broad application prospect in the field of thermoelectric cooling and power generation. what’s more. Now the most widely used materials is Bi2Te3. And it is one of the best thermoelectric materials at room temperature. The reflux method is an effective and simple method for the synthesis of nano thermoelectric material, it has the advantages of simple equipment, reaction of uniform and stable, low energy consumption, it has unique advantages in the aspects of nanocomposite . As the reflux method, which wish to prepare 0.75mmol nano Bi2Te3 sample, put some NaOH into the three-necked flask and then add 95ml distilled water to dissolve the NaOH.Then put 0.2871g Te powders as Te source into the three-necked flask, heat it to 100℃ and add 0.4730g BiCl3 as Bi source, at last add EDTA and 0.3g NaBH4. A very important place is that after one piece of drug was added, the residues on the inside wall should be wash away by distilled water. Then the temperature of the mixture of bottle is maintained at about 105 ℃, holding for 48 hours. 48 hours later , cool the three-necked flask to room temperature by natural and take out the product, wash and filter the reaction products with deionized water until the PH reach to 6-7. Take out the samples and dry it. The XRD test and electron probe of Bi2Te3 is to observe its image and microstructure. Analysis by XRD, the adding amount of changes in NaOH will lead to the generation of impurity in the sample, such as: generation of
III
山东科技大学学士学位论文
Abstract
目 录
1、 绪论.................................................................................................................1
1.1 热电材料综述........................................................................................1 1.1.1 1.1.2 1.2 热电材料的历史...........................................................................1 三个热电效应...............................................................................2
山东科技大学学士学位论文
摘要
摘 要
热电材料是一种功能材料，它可以实现电能与热能之间的直接相互转 换，其在热电制冷和温差发电领域有着非常广阔的应用前景。而现如今应 用最广泛的当属 Bi2Te3 材料，它是目前室温下性能最好的热电材料之一。 循环环流法是一种简单有效的合成纳米热电材料的方法，它具有设备简单、 反应均一稳定、能耗低等优点，在纳米合成方面有着独特优势。 本课题采用循环环流法来制备出 0.75mmol 的纳米 Bi2Te3 试样， 先称量 一定量的氢氧化钠加入 250ml 的三颈烧瓶中， 再向烧瓶中加入 95ml 的蒸馏 水，再称量 0.2871g 的 Te 粉作为 Te 源加入三颈烧瓶中，将此混合物加热到 100℃左右， 然后再加入 0.4730g 的 BiCl3 作为 Bi 源， 最后加入 0.3g 的 NaHB4 作为还原剂和一定量的 EDTA 作为络合剂，需要注意的是每加入一份药品 都要用蒸馏水冲洗掉三口烧瓶内壁上的残留。随后使瓶内混合物温度保持 在 105℃左右，保温 48 小时。之后停止保温，待其自然冷却到室温之后取 出产物，反应产物用去离子水反复洗涤过滤，直到 PH 值洗到 6-7 为止， 取 出样品并干燥。 对 Bi2Te3 作 XRD 测试及电子探针， 观察其物像和微观组织。 经 XRD 分析可知，改变 NaOH 的加入量会导致杂相如：单质 Te、Bi4Te3 的产生；改变 EDTA 的加入量会导致杂相-Te 单质的产生。观察 SEM 图像 发现，改变 NaOH 和 EDTA 的加入量导致了 Bi2Te3 形貌的变化。
images ，the addition of EDTA and NaOH can lead to changes of the patterns of Bi2Te3.
Keywords: Thermoelectric materials; Bi2Te3; Reflux method; NaOH; EDTA.
1.4
本课题的研究思路与内容..................................................................12
2、 材料制备与测试.......................................................................................13
2.1 2.2 2.3 2.4 实验原料..............................................................................................13 实验仪器..............................................................................................14 分析测试仪器......................................................................................14 实验工艺..............................................................................................15 2.4.1 2.4.2 2.5 实验方案.....................................................................................15 实验步骤.....................................................................................15
常见热电材料的分类............................................................................5 1.2.1 1.2.2 1.2.3 Bi2Te3 基热电材料........................................................................7 PbTe 基热电材料..........................................................................8 硅锗合金.......................................................................................9
1.3
热电材料的研究现状............................................................................9 1.3.1 1.3.2 热电材料的研究现状.................................................................10 制备 Bi2Te3 纳米材料的方法......................................................11
样品的测试..........................................................................................16 2.5.1 2.5.2 XRD 分析简介............................................................................16 SEM 简介....................................................................................17
i
山东科技大学学士学位论文
Abstract
3、 实验结果分析............................................................................................19
3.1 3.2 实验反应机理......................................................................................19 实验结果分析软件..............................................................................20 3.2.1 3.2.2 3.3 Jade 软件.....................................................................................20 Origin 软件..................................................................................22
本课题采用循环环流法来制备出075mmol的纳米bi2te3试样先称量一定量的氢氧化钠加入250ml的三颈烧瓶中再向烧瓶中加入95ml的蒸馏水再称量02871g的te粉作为te源加入三颈烧瓶中将此混合物加热到100左右然后再加入04730g的bicl3作为bi源最后加入03g的nahb4作为还原剂和一定量的edta作为络合剂需要注意的是每加入一份药品都要用蒸馏水冲洗掉三口烧瓶内壁上的残留
关键词：热电材料；Bi2Te3；循环环流法；NaOH；EDTA
I
山东科技大学学士学位论文
Abstract
Abstract
Thermoelectric material is a kind of functional material, it can come true the direct conversion between electric energy and heat energy , which has a broad application prospect in the field of thermoelectric cooling and power generation. what’s more. Now the most widely used materials is Bi2Te3. And it is one of the best thermoelectric materials at room temperature. The reflux method is an effective and simple method for the synthesis of nano thermoelectric material, it has the advantages of simple equipment, reaction of uniform and stable, low energy consumption, it has unique advantages in the aspects of nanocomposite . As the reflux method, which wish to prepare 0.75mmol nano Bi2Te3 sample, put some NaOH into the three-necked flask and then add 95ml distilled water to dissolve the NaOH.Then put 0.2871g Te powders as Te source into the three-necked flask, heat it to 100℃ and add 0.4730g BiCl3 as Bi source, at last add EDTA and 0.3g NaBH4. A very important place is that after one piece of drug was added, the residues on the inside wall should be wash away by distilled water. Then the temperature of the mixture of bottle is maintained at about 105 ℃, holding for 48 hours. 48 hours later , cool the three-necked flask to room temperature by natural and take out the product, wash and filter the reaction products with deionized water until the PH reach to 6-7. Take out the samples and dry it. The XRD test and electron probe of Bi2Te3 is to observe its image and microstructure. Analysis by XRD, the adding amount of changes in NaOH will lead to the generation of impurity in the sample, such as: generation of
III
山东科技大学学士学位论文
Abstract
目 录
1、 绪论.................................................................................................................1
1.1 热电材料综述........................................................................................1 1.1.1 1.1.2 1.2 热电材料的历史...........................................................................1 三个热电效应...............................................................................2
山东科技大学学士学位论文
摘要
摘 要
热电材料是一种功能材料，它可以实现电能与热能之间的直接相互转 换，其在热电制冷和温差发电领域有着非常广阔的应用前景。而现如今应 用最广泛的当属 Bi2Te3 材料，它是目前室温下性能最好的热电材料之一。 循环环流法是一种简单有效的合成纳米热电材料的方法，它具有设备简单、 反应均一稳定、能耗低等优点，在纳米合成方面有着独特优势。 本课题采用循环环流法来制备出 0.75mmol 的纳米 Bi2Te3 试样， 先称量 一定量的氢氧化钠加入 250ml 的三颈烧瓶中， 再向烧瓶中加入 95ml 的蒸馏 水，再称量 0.2871g 的 Te 粉作为 Te 源加入三颈烧瓶中，将此混合物加热到 100℃左右， 然后再加入 0.4730g 的 BiCl3 作为 Bi 源， 最后加入 0.3g 的 NaHB4 作为还原剂和一定量的 EDTA 作为络合剂，需要注意的是每加入一份药品 都要用蒸馏水冲洗掉三口烧瓶内壁上的残留。随后使瓶内混合物温度保持 在 105℃左右，保温 48 小时。之后停止保温，待其自然冷却到室温之后取 出产物，反应产物用去离子水反复洗涤过滤，直到 PH 值洗到 6-7 为止， 取 出样品并干燥。 对 Bi2Te3 作 XRD 测试及电子探针， 观察其物像和微观组织。 经 XRD 分析可知，改变 NaOH 的加入量会导致杂相如：单质 Te、Bi4Te3 的产生；改变 EDTA 的加入量会导致杂相-Te 单质的产生。观察 SEM 图像 发现，改变 NaOH 和 EDTA 的加入量导致了 Bi2Te3 形貌的变化。
images ，the addition of EDTA and NaOH can lead to changes of the patterns of Bi2Te3.
Keywords: Thermoelectric materials; Bi2Te3; Reflux method; NaOH; EDTA.
1.4
本课题的研究思路与内容..................................................................12
2、 材料制备与测试.......................................................................................13
2.1 2.2 2.3 2.4 实验原料..............................................................................................13 实验仪器..............................................................................................14 分析测试仪器......................................................................................14 实验工艺..............................................................................................15 2.4.1 2.4.2 2.5 实验方案.....................................................................................15 实验步骤.....................................................................................15
常见热电材料的分类............................................................................5 1.2.1 1.2.2 1.2.3 Bi2Te3 基热电材料........................................................................7 PbTe 基热电材料..........................................................................8 硅锗合金.......................................................................................9