Role of single-atom alloy catalysts in electrochemical conversion of carbon dioxide: A theoretical study

Atomic-scale understanding of C-C coupling in the electrocatalytic conversion of carbon dioxide (CO2) into valuable C2 chemicals remains elusive. Herein, we selected Group VIII and IB transition metals as active sites incorporated into the Cu(1 0 0) surface to construct single-atom alloy catalysts. The stability, selectivity, and activity of a series of catalysts were calculated using density functional theory. Fe, Co, Ni, Ru/Cu(1 0 0) exhibit the potential as candidates to generate C2 products and suppress the hydrogen evolution reaction (HER). The reaction proceeds through the reduction of CO2 to key intermediates *CO and *CHO, which undergoes C-C coupling to generate *CO-CHO, subsequently undergoing different protonation processes to yield diverse C2 products. The rate-determining step for Fe, Co, Ni, and Ru/Cu(1 0 0), is the hydrogenation of *CO, with a comparable energy barrier of 0.8 eV. Moreover, Fe and Co/Cu(100) favor the formation of C2H4 as the primary product, while Ni and Ru/Cu(1 0 0) predominantly produce CH3COOH.