Steering CO ₂ electroreduction toward ethanol production by a surface-bound Ru polypyridyl carbene catalyst on N-doped porous carbon

Abstract

Electrochemical reduction of CO₂ to multicarbon products is a significant challenge, especially for molecular complexes. We report here CO₂ reduction to multicarbon products based on a Ru(II) polypyridyl carbene complex that is immobilized on an N-doped porous carbon (RuPC/NPC) electrode. The catalyst utilizes the synergistic effects of the Ru(II) polypyridyl carbene complex and the NPC interface to steer CO₂ reduction toward C2 production at low overpotentials. In 0.5 M KHCO₃/CO₂ aqueous solutions, Faradaic efficiencies of 31.0 to 38.4% have been obtained for C2 production at -0.87 to -1.07 V (vs. normal hydrogen electrode) with 21.0 to 27.5% for ethanol and 7.1 to 12.5% for acetate. Syngas is also produced with adjustable H₂/CO mole ratios of 2.0 to 2.9. The RuPC/NPC electrocatalyst maintains its activity during 3-h CO₂-reduction periods.