高效稳定的铜分子筛用于柴油车尾气NOx去除研究

氨选择性催化还原技术(NH3-SCR)是柴油车NOx净化的主流技术之一。近年来, Cu基菱沸石小孔分子筛(Cu-CHA)由于其在NH3-SCR反应中的高活性和高水热稳定性而受到关注，并开始商业化应用。本项目以比传统合成方法更为经济、绿色的一步合成法和固相合成法制备的Cu-CHA分子筛为研究对象，深入研究Cu-CHA分子筛的水热稳老化机制，明确决定其水热稳定性的关键因素；深入研究硫、碳氢、水、磷等劣化因素对Cu-CHA分子筛催化剂的SCR性能的影响，揭示中毒机理，提出中毒催化剂再生策略；研究Cu-CHA分子筛催化剂的SCR反应机理，尤其是确定影响催化剂低温活性的决定因素；研究整体成型的Fe分子筛与Cu-CHA分子筛组成的SCR催化剂系统的协同效应。所得研究结果将对优化和设计合成高效的NH3-SCR分子筛催化剂提供新的思路和理论依据。

The selective catalytic reduction of NOx by NH3 (NH3-SCR) is one of the most promising technologies for NOx emission control for diesel vehicles. Recently, Cu-chabazite (CHA) catalysts have received much attention due to their high hydrothermal stability and activity in SCR reaction, and have been commercialized on diesel vehicles. This program focuses on Cu-CHA catalysts prepared by one-pot synthesis and solvent-free synthesis methods, which are considered as economical and “green” ways compared with conventional synthesis methods. In this project, the hydrothermal deactivation mechanisms of Cu-CHA catalysts will be investigated and the crucial parameters of hydrothermal stability will be clarified. The role of the various aging factors, including poisons like sulfur, hydrocarbon, H2O and phosphorous, on the performance of Cu-CHA catalysts will be studied and the poison mechanism will be revealed. Based on comprehensively results, the strategies to regeneration of poisoned catalysts can be proposed. The reaction mechanism of SCR reaction over Cu-CHA catalysts will be studied, specifically the key factors for controlling the reactivity of Cu-CHA in the low temperature range. In addition the effectiveness of a SCR catalytic system comprising Fe-zeolite and Cu-CHA catalysts monoliths will be examined by the experimental and modeling study. These results will provide new ideas and theoretical basis for optimizing and designing highly efficient NH3-SCR zeolites catalysts for the reduction of NOx from diesel exhaust.