Microiunetic Analysis of the Selective Catalytic Reduction (SCR) of Nitric Oxide Over Vanadia/Titania-Based Catalysts

Abstract

A microkinetic analysis of the selective catalytic reduction of nitric oxide by ammonia on vanadia/titania catalysts has been conducted. Besides the NO conversion, the “ammonia slip” which is a more sensitive measure of catalyst activity was also measured. Based on fundamental information obtained from TPD/TPR and in situ FTIR measurements, it has been possible to examine in detail the physical consistency of different reaction mechanisms. A simple, two-step Eley-Rideal mechanism with ammonia adsorption on a single site cannot account for all the experimental observations. However, both the kinetic and spectroscopic information may be explained either by introducing in the mechanism two sites for ammonia adsorption or by including an activation step of the adsorbed ammonia.