Microkinetic modeling of the NO + H2 system on Pt/Al2O3 catalyst using temporal analysis of products

A systematic experimental and modeling study of the NO + H-2 reaction system on Pt/Al2O3 catalyst was carried out using temporal analysis of products (TAP). A microkinetic model was developed that explains the transient product distribution during various experimental TAP protocols. NO pulsing experiments show the inhibiting effect of oxygen poisoning and the kinetic limitations posed by N-O bond scission. The NO-H-2 pump-probe experiments demonstrate the effect of temperature, H-2/NO ratio (>= 1), and pulse delay time between consecutive NO and H-2 pulses on N-2, N2O, and NH3 selectivity. The simulations reveal the competition between surface N-N recombination and N and/or NO reaction with H to form N-2 and NH3, respectively. The developed mechanistic-based microkinetic model accounts for all of the experimental data including the aforementioned selectivity versus pulse delay trends. (C) 2010 Elsevier Inc. All rights reserved.