Ce-Ti系烟气脱硝催化剂的中毒机理及提高抗中毒性能的探索

In view of the complexity and diversity of coal-fired flue gas in China，the unique performances of CeO2 in catalytic removal of NO and the resistance of TiO2 to SO2, this project will investigate poisoning mechanism of Ce-Ti based catalysts. Based on the obtained poisoning mechanism, the catalyst structure will be designed to improve their anti- poisoning performance. The research contents include: (1)The effect law and synergistic effect of the specific components released in coal combustion on Ce-Ti based catalysts will be investigated. (2)The effect of flue gas components on microstructures, surface acidity and redox properties over the catalysts will be elucidated. In order to implore the effect of flue gas components on the two active sites with acidity and intermediate evolvement in SCR reaction, the real active sites at different temperatures and surface active species will be discriminated by using NH3 or NO as a probe molecule. The action mechanism of flue gas components on the catalyst surface will be revealed and then be verified by the results of kinetic experiments. (3)Based on the poisoning mechanism of the catalysts, the microstructure and surface acid sites of the catalysts will be regulated. The internal relationships among constitutes, structure and anti-poisoning performance of the catalysts will be revealed. Finally, Ce-Ti based catalysts adaptive for coal-fired flue gas in China will be obtained.

针对我国燃煤烟气的复杂性和多样性，考虑到CeO2在催化脱硝方面的独特性能及TiO2的抗硫性能，拟开展Ce-Ti系催化剂的中毒机理研究，在此基础上对催化剂进行结构设计以提高其抗中毒性能。研究内容包括：(1)研究煤燃烧所释放的特定组分对Ce-Ti系催化剂的影响规律及多组分叠加的协同作用；(2)阐明烟气组分对催化剂表面微观结构、表面酸性、氧化还原特性的影响，以NH3和NO作为探针分子甄别不同反应温度下NH3-SCR反应真正的活性位点以及表面活性物种的变化，探索烟气组分对催化剂表面双酸活性位及SCR脱硝中间体演变的影响，揭示烟气组分与催化剂表面的微观作用机制，利用反应动力学实验的方法验证机理模型的可靠性；(3)以中毒机理为依据，对Ce-Ti系催化剂的微观结构和表面酸性位进行调控，探索催化剂的组成-结构-抗中毒性能之间的内在联系，设计适合我国燃煤烟气特性的Ce-Ti系催化剂。

针对我国燃煤烟气的复杂性和多样性，考虑到CeO2特有的Ce3+↔Ce4+变价活性以及优良的储氧/释氧能力，基于Ce-Ti系催化剂优良的NO脱除效果以及锐钛矿TiO2的抗硫性能，本项目就燃煤烟气组分对Ce-Ti系催化剂SCR脱硝活性的影响规律及作用机制展开研究。研究了煤燃烧所释放的特定组分对Ce-Ti系催化剂的影响规律及多组分叠加的协同作用，揭示Ce-Ti系催化剂组成-结构-脱硝性能之间的构效关系；研究了燃煤烟气组分对Ce-Ti系催化剂表面微观结构、活性组分的分散及化学状态、表面酸性、氧化还原特性等物理化学特性的影响，探索NH3-SCR反应中真正的活性位点和表面活性物种的变化，深刻认识烟气组分对Ce-Ti系催化剂表面双酸活性位及SCR脱硝中间体演变的影响，揭示烟气组分与Ce-Ti系催化剂的微观作用机制。本项目的实施有利于全面了解特定的Ce-Ti系催化剂，进一步指导Ce-Ti系催化剂的制备和改进，提高其对我国燃煤烟气的适应性，这对我国燃煤电厂烟气脱硝项目的可持续发展具有重要的战略意义。研究成果在国内外刊物上发表和录用论文11篇，其中SCI检索9篇（含一篇录用），EI检索1篇。项目负责人姜烨入选国家留学基金委“访问学者”，青岛市环境影响评价技术评估专家。