柴油车尾气净化用高性能NH3-SCR催化剂基础研究

氮氧化物（NOx）是光化学烟雾和灰霾形成的重要前体污染物。控制以柴油车为代表的机动车尾气NOx排放是我国大气污染治理的迫切需求，也是当今环境催化领域的研究热点。本项目以氨选择性催化还原NOx (NH3-SCR)的催化剂体系为研究对象，通过对氧化物催化剂的SCR反应性能、微晶结构、表面酸性位、反应机理的精确表征与理论模拟，明确氧化物催化剂上氧化还原位和表面酸性位在SCR反应中的协同作用及其构效关系；通过调控分子筛制备方法、硅铝比、活性组分物种和分布, 甄别影响催化剂活性和水热稳定性的关键因子；阐明分子筛孔道尺寸设计对催化剂抗中毒性能影响的规律。该项目的研究成果将有助于加深对SCR催化原理和催化剂构效关系的理解，指导金属氧化物和分子筛催化材料设计以提升催化剂低温活性、高温热稳定性和耐硫中毒能力，满足柴油车尾气净化对高性能SCR催化剂的苛刻要求。

Nitrogen oxides (NOx) in the atmosphere, as the key precursor pollutants, have been proven to induce the formation of photochemical smog and haze. Nowadays, catalytic purification of NOx emission from vehicle exhausts, particularly from diesel engines, is one of the hottest topics in environmental catalysis. In this project, we focus on the typical catalysts employed for the selective catalytic reduction of NOx with NH3 (NH3-SCR) reaction. By the study of catalytic performance, hydrothermal stability and sulfur durability of oxide catalysts as well as the characterization and simulation of microcrystalline structure, surface acid and redox sites, and the NH3-SCR reaction mechanism, we hope to accurately understand the interaction between redox sites and acid sites and the structure-activity relationship of oxide catalysts during the SCR reaction. By examining the effects of molecular sieve preparation methods, silica-alumina ratio, pore size, species and distribution of active components, we will identify the key factors regulating catalyst activity, hydrothermal stability and poisoning resistance. The potential results should lead to a deeper understanding of the reaction mechanism of the SCR reaction over oxide and zeolite catalysts and the principles for designing catalysts with high performance to meet the demanding requirements of diesel exhaust purification.