基于机动车尾气净化处理的新型质子导体研究

With the rapid increase of vehicle population in China, more and more environmental problems such as haze and acid rain are being caused by automobile exhaust pollution. It not only affects people's health, but also restricts the sustainable development of economy, so it is urgently needed to speed up the governance. The automobile exhaust purification treatment is an effective measures to prevent pollution, but the existing purification processing technology are dominated by some developed countries such as Europe, US and Japan. What's more, the core components in the common purification plant are almost precious materials which are scarce in resource and expensive in price. Therefore, seeking some alternatives of stable performance, low cost and high purification efficiency of alternatives is imperative. On the basis of our previous research, late-model proton conduct materials are proposed to be used in purification processing of automobile exhaust pollution in this project. The preparation method and process conditions for these proton conduct materials will be explored. The change low of crystal structure and micro-morphology with the variation of base materials, doping elements and doping amount will be studied. The effect factors, such as temperature, humidity and composition of the atmosphere on purification ability, working temperature, service life and other properties will be analyzed. The reaction course of purification processing will be studied and the effect mechanism of proton conduct materials in this course will be ascertained. This project aimed at screening effective proton conduct materials to be used in the purification processing for automobile exhaust pollution and establishing a new method of China's independent intellectual property in this field. This project also aims at providing theoretical foundation and scientific basis for the application of proton conductor materials in automobile exhaust pollution control.

随着我国汽车保有量的快速增长，汽车尾气污染带来的雾霾、酸雨等问题，不仅严重影响着人民群众的身体健康，而且制约着经济的可持续发展，急需加快治理。对汽车尾气进行净化处理是防止污染的有效措施，但现有的汽车尾气净化处理技术均为欧美日等发达国家所垄断，且净化装置多采用贵金属为核心材料，其资源稀缺、价格高昂，因此，寻找性能稳定、成本低廉、净化效率高的替代品势在必行。本项目依据前期研究，提出采用新型质子导体材料对汽车尾气进行净化处理，探索制备方法及工艺条件，研究其晶体结构、微观组织等性质随基体、掺杂元素及掺杂量的变化规律，探究温度、湿度、气氛等环境因素对质子导体的净化能力、工作温度、使用寿命等性能的影响，分析汽车尾气净化的反应历程，探明质子导体的作用机理，筛选出最佳的质子导体净化材料。建立具有我国自主知识产权的汽车尾气净化处理新技术，为质子导体材料在汽车尾气污染防治中的应用提供理论基础和科学依据。

汽车尾气等有毒、有害气体的催化净化技术一直以来是科研工作者研究的热点，现有的有害气体净化装置多采用价格昂贵的贵金属作为核心材料，且其核心技术为欧、美、日等发达国家所垄断。因此本项目提出采用较为廉价的质子导体材料替代或部分替代贵金属，研发新型催化剂材料，为建立具有我国自主知识产权的廉价催化剂生产技术奠定理论基础。. 项目研发出了基于质子导体的新型催化剂材料，开展了催化剂制备实验，采用溶胶-凝胶法制备了催化剂前驱体，利用高温焙烧法制备出相成分单一的催化剂材料，得到了最佳的制备工艺条件，成功制备出掺杂的BaCeO3基、SrCeO3基及CaZr1-xCexO3基等一系列催化剂材料，该类质子导体催化剂粉体成分均匀，分散度高，粉体的比表面积随着掺杂量的升高而升高，平均粒径为300-600nm。BCY和BCS的最佳焙烧温度为1500℃，BCP的最佳焙烧温度为1350℃，BCM的最佳焙烧温度为1250℃，BCW的最佳焙烧温度为1225℃。经过高温焙烧的质子导体具有良好的机械性能。通过研究发现了其晶体结构、微观组织等性质随基体、掺杂元素及掺杂量的变化规律。通过实验测定了材料的电化学性能，发现电导率随掺杂元素和掺杂量的变化规律，得到了最佳的掺杂元素及掺杂量。电化学测试发现，BCY质子导体的电导率随着掺杂量的升高而增大，随着Ba缺失量的增大而降低，CZCS、BCP和BCM电导率随着掺杂量增大而增大，SCY和BCS的电导率随着掺杂量的增大呈现先增大后减小的趋势。. 通过分析质子导体催化剂对CO、NOx和CH4的催化净化的反应历程，探明了该类质子导体催化剂在催化反应过程中的催化机理，实验结果表明Y掺杂量为0.15的催化剂对NOx催化还原效率提升了45%，Pd掺杂量为0.04的催化剂对CO催化净化反应的T50降低了55℃，Mn掺杂量为0.4的催化剂对CH4的催化氧化反应的T50降低了74℃。项目研究筛选出具有良好催化性能的复合型氧化物质子导体，应用于有毒、有害气体的催化净化处理，为基于质子导体的催化剂材料在气体污染防治中的应用提供理论基础和科学依据。