Fe-Exchanged Zeolites for Selective Catalytic Reduction of Nitric Oxide with Ammonia

本研究的目的是探讨铁交换沸石作为氮氧化物（Nox）选择性催化还原（SCR）催化剂的有效性。在初步工作中，PI发现包括ZSM-5在内的几种沸石比目前在许多固定SCR系统中使用的商业钒催化剂活性更高。此外，这些新型催化剂更能抵抗硫氧化物和水的失活。本文将采用四种不同的方法制备一系列铁交换沸石：传统的溶液离子交换法、改进的水溶液离子交换法、化学气相沉积法和固体离子交换法。孔隙小、硅铝比低的沸石是最有效的，将在本项目中使用。将研究稀土阳离子和氧化物作为促进剂。催化剂将通过中子活化分析和其他表面分析技术进行表征。稳态动力学和NO还原机制将在氨氧化的同时进行研究。燃烧产生的氮氧化物仍然是空气污染的主要来源。本研究将为铁沸石上氨还原NO的催化反应机理提供基础认识，从而开发出更优的SCR催化剂。

The objective of this proposal is to explore the effectiveness of iron-exchanged zeolites as catalysts for the selective catalytic reduction (SCR) of nitrogen oxide (Nox) species. In preliminary work the PI has found that several zeolites including ZSM-5 are much more active than the commercial vanadia catalysts currently used in many stationary SCR systems. Also, these new catalysts are more resistant to deactivation by sulfur oxides and water. A series of iron-exchanged zeolites will be prepared using four different methods: conventional solution ion-exchange, improved aqueous ion-exchange, chemical vapor deposition, and solid-sate ion exchange. Zeolites with small pores and low Si/Al ratios were found to be most effective and will be used in this project. Rare earth cations and oxides will be studies as promoters. Catalysts will be characterized by neutron activation analysis and other surface analysis techniques. Steady-state kinetics and the mechanism for NO reduction will be studies in parallel with ammonia oxidation. Nitrogen oxides resulting from combustion remain a major source of air pollution. This study will provide a fundamental understanding of the catalytic reaction mechanism for NO reduction by ammonia on Fe-zeolites, leading to the development of superior SCR catalysts.