Mechanism of CO Oxidation on Cu2O (111) Surface: A DFT and Microkinetic Study

Abstract

ABSTRACTCatalytic oxidation has been recognized as one of the most efficient and promising techniques for the abatement of CO and volatile organic compounds. In the present work, the CO oxidation mechanism on perfect Cu2O (111) surface was investigated by using density functional theory (DFT) calculations with the periodic surface model. The unsaturated singly coordinated Cu+ site of Cu2O (111) surface could effectively adsorb gaseous CO molecule with a strong adsorption energy of −1.558 eV. The adsorbed O on Cu2O (111) surface is very active toward CO oxidation with only 0.269 eV energy barrier. The reaction between CO and lattice O is the rate‐determining step of Mars‐van‐Krevelen (MvK) type CO oxidation with the energy barrier of 1.629 eV. The CO oxidation cycle initiated by the reaction between coadsorbed CO and O2 at the CuI site has a relatively lower energy barrier of 1.082 eV and is, therefore, more likely to proceed compared with the MvK cycle. Microkinetic rate constants of elementary reaction steps based on the transition state theory were deduced, which could be helpful in the kinetic modeling of CO oxidation on Cu2O surface.