Selective oxidation of ammonia on RuO 2(1 1 0): A combined DFT and KMC study

Abstract

We have used a combination of density functional theory (DFT) and kinetic Monte Carlo (KMC) simulations to calculate the reaction rates for the selective oxidation of ammonia on RuO 2(1 1 0). Our KMC simulations of 18 reactions among NH x ( x =0–3) and OH x ( x =0–2) species on RuO 2(1 1 0) show 93% selectivity for NO, in close agreement with experiment (∼95%). The chief factor in the high selectivity for NO on the RuO 2(1 1 0) surface is the significantly reduced N diffusion (via N blocking) caused by various intermediates present on the RuO 2(1 1 0) surface, which severely inhibits the recombination rate of N + N → N 2 but interfere far less with that of N + O → NO owing to the nearby availability of O from dissociation of O 2.