钒钨铈催化剂的低温SCR反应机理研究

本文使用等体积浸渍法制备了钒钨铈(V2O5-WO3/CeO2)选择性催化还原(SCR)脱硝催化剂,并使用一系列的原位傅里叶变换红外(In-situ FTIR)光谱详细研究了该催化剂的低温SCR反应过程(本文选用200℃)。通过将原位红外光谱与化学诱捕法耦合使用,成功捕捉并识别了低温SCR的不稳定反应中间产物亚硝酸盐(nitrites),并以该亚硝酸盐物种为主要的反应活化产物,建立了基于NO氧化活化的低温SCR还原半圈反应动力学模型.该动力学模型可准确描述V2O5-WO3/CeO2催化剂低温SCR中NO与表面吸附NH3的瞬态反应过程。

Mechanistic Investigation of the Low-temperature Selective Catalytic Reduction of NO Over VOx-WO3/CeO2 Catalyst

V2 O5-WO3/CeO2,a catalyst for the selective catalytic reduction(SCR) of NOx,was synthesized using the impregnation method.A series of In-situ FTIR spectroscopy were applied to investigate the redox mechanism of low-temperature(LT) SCR(200℃ in the present work) over V2 O5-WO3/CeO2.In particular,coupling In-situ FTIR with a chemical trapping technique effectively captures and identifies nitrites as the product of NO oxidative activation,which are widely reported as the primary intermediates of the low-temperature SCR.A kinetic model on the basis of such NO oxidative activation was proposed,and was able to accurately describe the reduction half cycle of LT-SCR over V2 O5-WO3/CeO2,specifically the transient reaction between NO and NH3 adsorbates.