Facet Dopant Regulation of Cu2O Boosts Electrocatalytic CO2 Reduction to Formate

Electrochemical carbon dioxide reduction reaction (CO2RR) using clean electric energy provides a sustainable route to generate highly-valuable chemicals and fuels, which is beneficial for realizing the carbon-neutral cycle. Up to now, achieving a narrow product distribution and highly targeted product selectivity over Cu-based electrocatalysts is still a big challenge. Herein, sulfur modification on different crystal planes of cuprous oxide (Cu2O) is demonstrated, results in an improvement for formate generation to different degrees. Experimental results and density functional theory (DFT) calculations reveal that sulfur species modified on the surface of Cu2O (100) facet effectively lower the formation energy of key intermediate *OCOH for formate generation compared with Cu2O (111) facet. As a consequence, the modification of p-Block elements over Cu-based electrocatalysts is an effective strategy to optimize the adsorption energy of key intermediate during CO2RR, leading to a highly selective product.