论文总字数：19045字

摘 要

随着石油，煤等不可再生资源的日益消耗，天然气逐渐在能源中占据重要位置^[1]，然而目前将甲烷转化为醇或烯烃的过程很复杂且花费高，因为需要中间步骤来把甲烷变为合成气体，所以尚需进一步的研究。目前人们发现可以较为有效的利用天然气的方法——甲烷氧化偶联（OCM）。然而，即使是利用OCM来制备乙烯，得到C₂产物的单程收率依然达不到工业生产规模的要求。因此，为了提高OCM的单程收率，人们在开始关注于研究新的催化剂。

人们发现Bi₂O₃的禁带宽度较窄，能够在可见光范围内响应，因此具有较好的催化性能。为了进一步拓展它的光谱响应范围，减少禁带宽度，人们利用掺杂，减少催化剂粒径等方法提高催化性能。

本文以氧化铋系材料为基础，利用水热-焙烧法制备Y掺杂的Bi₂O₃催化剂。实验原料中组成元素为Y和Bi，且都是氧化物的形式。理论上讲，随着Y掺杂量的变化，Bi₂O₃的晶体结构应随之发生改变。然而实验发现，利用X射线衍射分析知，利用水热-焙烧法制得的催化剂还是单斜晶型，且图谱显示无明显的衍射峰偏移，所以这表明Y有可能未能成功掺杂进入Bi₂O₃，但得到制得的Bi₂O₃较纯，基本无杂质。还需进一步利用其他测试方法来鉴定是否掺杂成功。

关键词： Bi₂O₃催化剂 Y掺杂 稀土元素

Effect of ion doping on the structure of Bi₂O₃

Abstract

With the increasing consumption of oil, coal and other non renewable resources, natural gas gradually occupy an important position in the energy, however, the conversion of methane into the process of alcohol or olefin is very complicated and costly, because of the need of intermediate steps to methane into synthesis gas, so it still need further research. At present, people have invented the method of preparing ethylene by using oxidative coupling of methane (OCM), which can make good use of natural gas. However, even if OCM is used to prepare ethylene, the one-way yield of C₂ products is still not up to the scale of industrial production. Therefore, in order to improve the one-way yield of OCM, people began to pay attention to the study of new catalysts.

It is found that the band gap of Bi₂O₃ is narrow enough to respond in the visible range and has good catalytic performance. In order to further broaden the spectral response range and reduce the band gap, doping and reducing the particle size of catalyst are used to improve the catalytic performance.

Based on bismuth oxide materials, Y doped Bi₂O₃ catalysts were prepared by hydrothermal calcination method. The experimental materials are composed of Y and Bi, both of which are in the form of oxides. Theoretically, the crystal structure of Bi₂O₃ should be changed with the change of Y doping content. However, experiments, analysis by X ray diffraction, the prepared catalyst is monoclinic, and the map showed no obvious diffraction peak shift, so it indicated that Y could not successfully doped into the Bi₂O₃, but Bi₂O₃ was the relatively pure, no impurities. Further testing is needed to determine whether doping is successful.

Keywords: Bi₂O₃ catalyst; Y doping; rare earth element

目 录

摘 要

Abstract

第一章 绪论

1.1 甲烷的利用

1.2 甲烷的氧化偶联技术研究

1.2.1 OCM反应机理

1.2.2 OCM反应热力学与动力学

1.2.3 OCM反应器的研究

1.2.4 OCM催化剂的研究

1.3 光催化技术

1.3.1 光催化原理

1.3.2催化活性的影响因素

1.3.2.1影响催化剂活性的因素

1.3.2.2 反应条件对光催化效果的影响

1.3.4 光催化技术的研究现状

1.4新型铋系光催化剂

1.4.1 元素Bi及铋系催化剂

1.4.2 Bi₂O₃结构及性能的影响因素

1.4.2.1 pH值的影响

1.4.2.2 表面活性剂的影响

1.4.2.3 制备温度和时间影响

1.4.3 提高Bi₂O₃催化性能的方法

1.4.3.1 表面贵金属沉积

1.4.3.2 复合催化剂

1.4.3.3 半导体的光敏化

1.4.3.4 离子掺杂改性

第二章 Y掺杂Bi₂O₃催化剂制备

2.1 实验材料

2.2 实验仪器

2.3 掺杂Y的Bi₂O₃光催化剂制备

2.3.1 制备方法

2.4 掺杂Y催化剂样品X射线衍射表征

第三章 结果与讨论

3.1 Bi₂O₃的XRD图谱分析

3.2 XRD全谱拟合图分析

3.3 实验结论

3.3.1 衍射峰未偏移的原因分析

第四章 结论与展望

参考文献 22

致 谢 24

第一章 绪论

1.1 甲烷的利用

请支付后下载全文，论文总字数：19045字