Amorphous, Periodic Model of a Copper Electrocatalyst with Subsurface Oxygen for Enhanced CO Coverage and Dimerization

Oxide-derived copper electrocatalysts have been found to possess excellent selectivity toward the production of multicarbon products from CO,. The presence of subsurface oxygen in these catalysts has been confirmed experimentally, but the resulting amorphous structure has yet to be captured by theoretical models. In this study, the role of subsurface oxygen atoms is investigated with density functional theory, using a disordered oxide-derived Cu surface model (d-ODCu). The presence of subsurface oxygen atoms increases the maximum adsorption coverage of the important CO intermediate but decreases that of H atoms because of electronic and geometric effects. However, this has no significant influence on the free-energy activation barrier or endothermicity of the CO-dimerization reaction step, allegedly the key to multicarbon product formation.