铜基菱沸石（Cu-CHA）用于NH3选择性催化还原NOx研究

氨选择性催化还原技术(NH3-SCR)是柴油机NOx净化的主流技术。Cu基菱沸石小孔分子筛(Cu-CHA)在NH3-SCR反应中表现出比其他Cu分子筛更好的低温活性和水热稳定性。本项目在调研国内外相关研究和前期预研的基础上，开展以Cu-SSZ-13和Cu-SAPO-34为代表的Cu-CHA分子筛用于NH3-SCR净化NOx研究。采用含铜模板剂直接合成Cu-CHA分子筛，研究Cu-CHA的分子筛骨架结构、Cu物种存在状态、共存阳离子与NH3-SCR反应性能的构效关系；研究直接合成和离子交换制备的Cu-CHA分子筛的水热稳定性,表征水热老化对分子筛骨架和Cu物种的影响，探讨水热失活机制，考察SO2、碳氢化合物等共存组分对Cu-CHA催化活性的影响机理；调变催化剂组分、结构和反应气氛以提高催化剂稳定性和抗中毒能力，为研制可满足柴油机尾气净化实际应用需求的新型催化剂提供科学依据和技术储备。

The selective catalytic reduction of NOx by NH3 (NH3-SCR) is one of the most promising technologies for NOx emission control for diesel engines. Cu-chabazite (CHA) catalysts show higher activity at low temperatures and better hydrothermal stability, compared to other Cu-based zeolites. This project will study the performance of Cu-CHA zeolites as SCR catalysts based on the current achievements made by both domestic and foreign researchers and our preliminary research. A series of Cu-CHA will be prepared by one-pot synthesis using copper containing templates. The relationship between framwork structure, Cu species, co-cations and catalytic activity of Cu-CHA catalysts for NH3-SCR of NOx will be investigated in detail. Moreover,the NH3-SCR activity and hydrothermal stability of Cu-CHA prepared by one-pot synthesis and by ion-exchange method will be compared. By studying the effect of hydrothermal deactivation on zeolite framework and Cu species, the suggestions for the improvement on hydrothermal stability of Cu-CHA can be proposed. For application consideration, the effect of co-existence of SO2, hydrocarbons etc. on the activity of Cu-CHA will also be studied. The catalyst composition, structure and reaction atmosphere can be tuned to enhance the stability and durability of catalysts. The catalytic materials for practical application on diesel engines can be developed eventually.