Experimental results describing the product distribution during the reduction of NO by H-2 on Pt/Al2O3 and Pt/BaO/Al2O3 catalysts are presented in the temperature range 30-500 degrees C and H-2/NO feed ratio range of 0.9-2.5. A microkinetic model that describes the kinetics of NO reduction by H-2 on Pt/Al2O3 is proposed and most of the kinetic parameters are estimated from either literature data or from thermodynamic constraints. The microkinetic model is combined with the short monolith flow model to simulate the conversions and selectivities corresponding to the experimental conditions. The predicted trends are in excellent qualitative and reasonable quantitative agreement with the experimental results. Both the model and the experiments show that N2O formation is favored at low temperatures and low H-2/NO feed ratios, N-2 selectivity increases monotonically with temperature for H-2/NO feed ratios of 1.2 or less but goes through a maximum at intermediate temperatures (around 100 degrees C) for H-2/NO feed ratios 1.5 or higher. Ammonia formation is favored for H-2/NO feed ratios of 1.5 or higher and intermediate temperatures (100-350 degrees C) buts starts to decompose at a temperature of 400 degrees C or higher. The microkinetic model is used to determine the surface coverages and explain the trends in the experimentally observed selectivities. (C) 2007 Elsevier B.V. All rights reserved.