Progress and perspectives for electrochemical CO2 reduction to formate

Electrochemical CO2 reduction (CO2RR) is an environmentally friendly approach to transform greenhouse gas CO2 to value-added chemical feedstocks and fuels. One of the most promising CO2RR products is formate with widespread commercial applications across chemical, food, and energy related industrials. An ideal high performing CO2 electrolyser to synthesis formate should operate stably with high formate conversion efficiencies, at high current densities and low voltage that meeting industrial technoeconomic requirements. Significant progresses have been achieved in the past decades in the development of advanced catalysts, electrolyte engineering, and electrolyser designs that improved overall CO2 electrolysis performance. In-depth fundamental understanding of electrocatalytic reaction mechanisms was achieved through advanced in-situ analytical techniques. Although lab-scale electrolysers are relatively well-developed, it is still not reaching maturity level for industrial formate manufacturing that requires stable and efficient cell performance at economic scales. Here, CO2RR mechanistic studies including the employed advanced techniques for formate production are reviewed. Recent advances in the syntheses of p-block post-transition and transition metal-based catalysts and their performances are discussed. The main strategies for performance improvements including catalyst optimisation, electrolyte control, and cell designs, are critically assessed. Finally, we offer perspectives on future developments of CO2RR to formate.