高效N2O分解催化剂制备及反应机理研究

Nitrous oxide (N2O) is one kind of the greenhouse gases controlled emission in the Kyoto Protocol. The catalytic decomposition of N2O is the most promising abatement methods. The redox core of catalysts of zeolite loading cobalt is afforded by Co2+ and Co3+ ion. The activity of catalysts is affected by the ratio of Co2+ and Co3+, particle size and dispersion of cobalt species. With using micro-emulsion as impregnated liquid, controlling reducibility of calcining gas and calcining temperature and time, the zeolite loading cobalt catalysts, having different Co2+ and Co3+ contentand high-dispersed cobalt species , are synthesized. The composition, structure, physical and chemical properties of catalysts will be characterized by advanced analysis and test technology, and the catalytic activity of catalysts will be evaluated in Micro-reactor. The reaction pathway and catalytic mechanism of N2O catalytic decomposition on the zeolite loading cobalt catalysts can be revealed by in-situ FTIR and in-situ characterization. The structure-activity relationship of catalyst activity of N2O decomposition can be established through a comprehensive analysis of catalysts characterization results and the evaluation of catalyst activity results. The basis data and theoretical guidance will be provided for the development of highly active catalysts of N2O decomposition.

氧化亚氮（N2O）是《京都议定书》规定减排的温室气体之一，催化分解是最有前景的N2O减排方法。分子筛载钴催化剂中Co2+和Co3+是进行氧化还原反应的核心，其粒度和分散性均影响催化剂活性。本项目在催化剂制备中，控制催化剂焙烧气氛还原性及焙烧温度等，制备出钴物种高度分散的钴催化剂；采用先进分析测试技术对催化剂进行表征，在微型反应器中对催化剂活性进行评价；通过原位表征技术，研究反应气氛等对分子筛载钴催化剂上N2O分解反应的影响。综合分析催化剂表征结果，结合催化剂活性评价结果，探讨催化剂组成、结构、理化性质等与催化剂催化分解N2O活性的关系，初步探讨其催化反应机理，为开发高活性N2O分解催化剂提供基础数据和理论依据。

氧化亚氮（N2O）是己二酸生产过程中的重要副产物，是列于CO2和CH4之后的第三大温室气体，催化分解是最有前景的N2O减排方法。本研究制备了分子筛负载钴基尖晶石复合氧化物催化剂及高分散纳米Co3O4尖晶石复合氧化物催化剂，探讨了载体种类、活性组分用量、催化剂助剂、制备方法、制备条件等对催化剂氧化还原性能及催化活性的影响。考察了反应气氛对N2O催化分解过程的影响，初探了N2O催化分解反应机制。研究结果表明：1. 载体特性、钴负载量、焙烧温度等均影响催化剂催化分解N2O的活性，分子筛负载钴基尖晶石催化剂，钴的负载量为5%即可获得较高的催化活性，适宜的焙烧温度为600-700℃，焙烧温度达到700℃时催化剂中有难还原的Co-Al-O物种生成；添加助剂不能改善Co3O4/ZRP的催化活性，甚至对其活性有抑制作用。2. 反应体系中氧浓度对N2O催化分解过程无显著影响，提高空速或SO2的存在使N2O催化分解温度升高。3. 制备方法与条件影响纳米Co3O4的氧化还原性及其表面组成，从而影响其催化性能。4. 反应机制初探结果显示，催化剂的表面吸附氧种对N2O催化分解至关重要。总之，本研究制备的分子筛载钴催化剂对N2O分解表现出优异活性，有望在实际生产中应用。