Mechanism of the Vanadium Oxide-Catalyzed Selective Reduction of NO by NH₃. A Quantum Chemical Modeling

Quantum chemical calculations have been performed using density functional theory to model the mechanism of selective catalytic reduction of NO by NH 3 on vanadium oxide. The reaction is initiated by NH 3 adsorption on a Brønsted site modeled as a dimer cluster model representative of vanadium oxide, containing a terminal V O adjacent to a V−OH group. The calculations indicate that the adsorbed NH 3 behaves as NH 4 +, which is supported by calculated IR spectra. Subsequently NO reacts with this activated NH 3 to yield NH 2 NO and finally the reaction products N 2 and H 2 O. The present results give support to a dual-site Eley−Rideal-type mechanism involving a Brønsted site and agree with isotopic labeling studies.