Applied Catalysis B: Environmental, Vol.168, 429-440, 2015
Kinetic modelling of the NOx reduction by H-2 on Pt/WO3/ZrO2 catalyst in excess of O-2
This paper addresses the elementary kinetic mean field modelling of the NOx reduction by H-2 on Pt/WO3/ZrO2 under oxygen-rich conditions. Pt/WO3/ZrO2 was recently shown to reveal substantial low-temperature deNO(x) activity with enhanced N-2 selectivity referred to traditional Pt catalysts. The model was developed based on a postulated reaction mechanism as well as kinetic examinations and implied a network of 48 reaction steps described by Arrhenius-based rate expressions. Kinetic parameters were taken from literature and by fitting calculations, while pre-exponential factors of adsorption were estimated from kinetic gas theory. For validation, experiments were simulated and thermodynamic consistency was proven by checking the Gibbs free enthalpy of the catalytic surface reactions. As a result of the kinetic model, the formation of OH surface species was identified as the rate determining step of H-2 oxidation, while the reduction of NO predominately occurs by dissociation of chemisorbed NO. (C) 2014 Elsevier B.V. All rights reserved.