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原位漫反射红外光谱研究NO在Ag/SAPO 34催化剂上的选择性催化还原过程。考察了以丙烯为还原剂 ,在富氧及 573～ 773K温度条件下的反应。通过比较初始混合气中加氧或不加氧时反应的原位光谱 ,探讨了氧在NO还原过程中的作用。结果表明 ,氧能充分促进丙稀活化以及增加NOx 吸附态含量 ,并且氧的存在是有效产生有机 氮氧化物 (R NO2 ,R ONO)不可缺少的条件。基于光谱实验 ,认为反应机理为 :NO ,丙烯和氧反应 ,在Ag/SAPO 34催化剂上生成吸附的有机 氮氧化物 ,再由这些吸附物种分解成N2 ,催化还原的关键是形成有机 氮氧化物中间体。
In Situ Diffuse Reflectance Infrared Spectroscopy Study on Selective Catalytic Reduction of NO on Ag / SAPO 34 Catalyst. The reaction of propylene with reducing agent at oxygen-rich temperature of 573-773K was investigated. The effect of oxygen on the reduction of NO was discussed by comparing the in situ spectra of the initial mixed gas with or without oxygen. The results show that oxygen can fully promote the activation of propylene and increase the content of NOx, and the existence of oxygen is an indispensable condition for effectively producing organic nitrogen oxides (R NO2, R ONO). Based on the spectroscopic experiments, it is considered that the reaction mechanism is as follows: NO, propylene and oxygen react to form adsorbed organic nitrogen oxides on the Ag / SAPO 34 catalyst, and then the adsorptive species decompose into N2. The key of the catalytic reduction is to form organic nitrogen oxides Intermediate.