Migration of sulfur regulates products distribution of electrochemical reduction of carbon dioxide

By synthesizing Cu 7 S 4 catalysts with abundant structural defects from Cu 2 O aerogels as precursors, the influence of sulfur on CO 2 RR is investigated. On the surface of the Cu 7 S 4 catalyst, the conversion of CO 2 to C 2 H 5 OH can be achieved under less negative potential conditions. At more negative conditions, Cu 7 S 4 undergoes reconstruction, and the dominant product shifts to HCOOH due to the dissolution of sulfur elements, which is caused by the adsorption of sulfur atoms on the metal Cu surface after the restructuring of Cu 7 S 4 . On the surface of Cu aerogels with low concentration of adsorbed sulfur atoms, a maximum FE of 79.4 % for HCOOH is achieved at –1.2 V vs. RHE. Density functional theory (DFT) calculations indicate that sulfur atoms located the lattice and those adsorbed on the surface post-dissolution favor the formation of C 2 products and HCOOH, respectively.