Direct versus hydrogen-assisted dissociation of CO on iron surfaces: Kinetic Monte Carlo and microkinetic modeling

Abstract

Microkinetic modelling in conjunction with Kinetic Monte Carlo (KMC) simulations were employed to study the direct versus hydrogen-assisted dissociation of CO on iron surfaces. For the activation barriers of the reactions, DFT documentation was considered. The production of C, O, HCO, COH, CH, and OH was assessed to compare the behaviour of CO⇌C + O, H + CO⇌CH + O and H + CO⇌C + OH reactions at identical conditions of pressure and temperature. It was observed that, for the studied temperature conditions 300–450 K, the reactions coexist to 300–370 K, and present selective predominance depending of the temperature range, being the direct dissociation of CO the route with the highest conversion at temperatures above 450 K, and hydrogen-assisted the main reaction between 350 and 400 K.