Electro-synthesis of valuable products by coupling energy-saving anodic alcohol oxidation reaction with cathodic CO2 reduction reaction

Electrocatalytic carbon dioxide reduction reaction (CO2RR) offers a promising pathway towards achieving carbon neutrality. However, its efficiency is hindered by the sluggish oxygen evolution reaction (OER) at the anode, which consumes a significant portion of the energy input. Herein, we report an effective strategy to replace OER with energy efficient alcohol oxidation reactions to produce value-added products at both cathode and anode of the electrolyzer. In an integrated cell, CO2RR is carried out at cathode using tin oxide deposited on porous copper (SnOx@pCu@CF) as an electrocatalyst while alcohol oxidation reactions (methanol, ethanol, benzyl alcohol) are conducted on porous copper (pCu@CF) anode in alkaline electrolyte. Over 89% selectivity for the cathodic reduction of CO2 into formate and almost 100% selectivity for anodic oxidation of methanol to formate, ethanol to acetate and benzyl alcohol to benzoate are achieved at high current densities within a wide potential range. The SnOx@pCu@CF//pCu@CF two-electrode arrangement required 100 mV less potential for the overall methanol-assisted CO2RR as compared to water oxidation assisted CO2RR with simultaneous production of valuable formate at both anode and cathode This study underscores the potential of coupling CO2RR with viable alternative oxidation reactions as a theoretically and technically feasible approach as well as holds significant promise for delivering substantial economic benefits.