The reactivity of CO2 and H2 at trapped electron sites at an oxide surface

We investigate the reactivity to H 2 of a chemisorbed CO 2 species at electron traps on oxide surfaces, taking the single electron F + oxygen vacancy of the MgO(100) terrace as a model system. We find that multiple hydrogen addition steps form three interacting catalytic cycles, leading to the evolution of formaldehyde, methanol or methane. Our results have general implications for the reactivity of CO 2 on metal oxides. A series of model catalytic cycles for CO 2 conversion at metal oxide surface vacancy sites is presented.