A computational study of CO oxidation on IrO2 (1 1 0) surface

Abstract

Though, oxygen-rich iridium oxide (O-IrO2 (110)) surface exhibits excellent catalytic activity towards methane activation and oxygen evolution reactions, the CO oxidation mechanism on this surface remains elusive. Here, we used density functional theory calculations, ab initio molecular dynamics (AIMD), and microkinetic simulations to explore the CO oxidation reactions via Langmuir-Hinshelwood (L-H), Eley-Rideal (E-R), and Mars-Van Krevelen (MvK) mechanisms on O-IrO2 (110) surface. We find that the C-O coupling and CO2 desorption are the rate-determining steps in L-H and E-R mechanisms, respectively. The CO oxidation via the MvK mechanism on the IrO2 (110) surface is more difficult to proceed. Both AIMD and microkinetic simulation results demonstrate that CO2 can desorb from the O-IrO2 (110) surface at 400 K. The production temperature of CO2 on the O-rich IrO2 (110) surface via E-R mechanism is lower than that via the L-H mechanism. Therefore, we predict that the O-rich IrO2 (110) surface can accelerate the CO oxidation reaction rate.