Reaction mechanism for CO oxidation on Cu(3Â 1Â 1): A density functional theory study

► The CO oxidation on Cu(3 1 1) surface was investigated by density functional theory computations. ► O2 dissociation is highly dependent on the orientation and site of the adsorbed oxygen molecule. ► The energetically most favorable site for CO molecule on Cu(3 1 1) is the step edge. ► The reaction barrier of CO + O → CO2 is about 0.3 eV lower than that of CO + O2 → CO2 + O.