环境友好的选择性催化还原氮氧化物催化剂

Environmental-friendly catalysts for the selective catalytic reduction of NO_x

富氧条件下的氮氧化物(NOx)选择性催化还原(SCR)是目前环境催化领域的研究热点,其核心问题是研发环境友好、高效稳定的SCR催化剂.目前,以NH3为还原剂的NH3-SCR已经大规模应用于固定源烟气脱硝和柴油车尾气净化,以碳氢化合物(HC)为还原剂的HC-SCR也有望实际应用.针对NH3-SCR,本文以作者研究的铁钛复合氧化物催化剂、铈基氧化物催化剂以及国际上新兴的小孔分子筛催化剂为例,从催化剂结构、SCR反应机理、催化剂低温活性改进以及抗中毒性能等诸多方面对该领域的研究进展做了较为全面的论述.针对HC-SCR催化剂,本文在综述长链HC及柴油选择性还原NOx研究现状的基础上,结合作者在HC-SCR反应机理方面的研究成果,展望了实现柴油-SCR的发展方向.

Selective catalytic reduction （SCR） of nitrogen oxides （NOx） under oxygen-rich conditions is a research hotspot in the field of environmental catalysis, of which the core problem i,; to develop environmental-friendly, highly effective and stable SCR catalyst systems. At present, the NHa-SCR technique using urea/NH3 as reducing agent has already been widely applied for stationary flue gas denitrogenation and diesel engine exhaust purification. The HC-SCR technique using hydrogen carbons （HC） as reducing agent is also promising for practical application. For urea/NH3-SCR system, in this paper, the research progress of iron titanate catalyst, cerium-based oxide catalysts and small-pore zeolite catalysts is comprehensively summarized, including the catalyst structure, the SCR reaction mechanism, the improvement of low temperature activity and also the poisoning resistance performance. For HC-SCR system, herein, the SCR of NOx by higher HCs/diesel, and the achievements irt the mechanism study of HC-SCR are summarized systematically, which can provide new guideline for the develc,pment and application of diesel-SCR technique.