Selectivities of Cu edges surface environment for C1 and C2 pathways

Abstract

Copper (Cu) is an effective catalytic material for the electrochemical CO2 reduction reaction (CO2RR). The final products are highly reliant on surface conditions, and edge models can effectively expose different surface environments, which provide a large number of representative adsorption sites. Compared with the traditional Cu(111), the change of coordination number (CN) and the formation of OCu bond greatly increase the number of electrons transferred during CO2 activation. First-principles calculations have found that the adsorption site at the outer edge (6-site) of the step surface exhibits a significant advantage in both the C1 and C2 pathways. Due to its minimum CN, there is deep p-d hybridization, resulting in the lower Gibbs free energy (G) at the rate-determining steps (RDS). Specifically, the overpotentials are only 0.74 and 0.66 V during C1 and C2 pathways, respectively, indicating good catalytic performance. Differences in surface conditions will inevitably induce better adsorption state of intermediates, optimizing the selectivity of CO2RR. Our current work potentially provides a new avenue for designing more efficient and selective Cu electrocatalysts.