Electrochemical Conversion of CO₂ to Syngas with Controllable CO/H₂ Ratios over Co and Ni Single‐Atom Catalysts

Abstract

The electrochemical CO₂ reduction reaction (CO₂ RR) to yield synthesis gas (syngas, CO and H₂ ) has been considered as a promising method to realize the net reduction in CO₂ emission. However, it is challenging to balance the CO₂ RR activity and the CO/H₂ ratio. To address this issue, nitrogen-doped carbon supported single-atom catalysts are designed as electrocatalysts to produce syngas from CO₂ RR. While Co and Ni single-atom catalysts are selective in producing H₂ and CO, respectively, electrocatalysts containing both Co and Ni show a high syngas evolution (total current >74 mA cm^-2 ) with CO/H₂ ratios (0.23-2.26) that are suitable for typical downstream thermochemical reactions. Density functional theory calculations provide insights into the key intermediates on Co and Ni single-atom configurations for the H₂ and CO evolution. The results present a useful case on how non-precious transition metal species can maintain high CO₂ RR activity with tunable CO/H₂ ratios.