Tunable Cu-M bimetal catalysts enable syngas electrosynthesis from carbon dioxide

The catalytic reduction of CO₂ to produce syngas (CO₂RR-to-syngas) gives a practicable way to utilize CO₂. However, the scale relationships between the adsorption energies of the CO₂ reduction intermediates severely restrict the catalytic performance of catalysts. Herein, we design Cu-M bimetal catalysts (BMCs) to break through the stubborn restriction of scaling relationships on catalytic activity. Density functional theory (DFT) was used to investigate the CO₂RR activity of Cu-based BMCs. It is found that the dual-atom sites (Cu site and M site) result in noteworthy deviations for the scaling relationships between COOH* and CO*. The Cu-Cr catalyst shows the best CO₂RR activity towards CO production. Specifically, only a low overpotential of 0.326 V is required to enable CO₂ reduction to CO. The Cu-Rh catalyst shows a good HER activity due to the lower absolute ΔG_H value. The electrons entering the antibonding orbital significantly increase the Pauli repulsion, which weakens the adsorption energy of atomic hydrogen on the catalysts. The d-band center (epsilon(d)) is not a good descriptor for the HER and CO₂RR over BMCs. Cu-W and Cu-Mo have comparable reaction free energies of the first step involved in the HER and CO₂RR processes, and are expected to be the most suitable catalysts for CO₂RR-to-syngas. (authors)