Coupling Electrocatalytic CO2 Reduction with Methanol Oxidation for Dual Formate Electrosynthesis: A Review

Abstract The electrochemical CO2 reduction reaction (CO2RR) offers a promising pathway for producing valuable chemicals, such as formate, often achieving high selectivity under optimized conditions. The reduction of CO2 to formate involves a two-electron transfer at a low potential (−0.12 V vs RHE), making it highly attractive for practical deployment. Despite significant research, its large-scale implementation is challenging due to the energy-intensive anodic oxygen evolution reaction (OER) traditionally paired with CO2 reduction. Coupling the CO2RR with the methanol oxidation reaction (MOR) offers an alternative strategy, in which methanol can be selectively converted to formate at lower anodic potentials than the OER, there by reducing overall cell voltage while generating value-added products at both electrodes. In this review, we first summarize the fundamentals of both selective electrochemical reduction of CO2 to formate (CO2RTF) and methanol oxidation to formate (MOTF), which includes mechanistic studies, electrolyzer configurations, and electrolyte effects. Next, we highlight the latest advancements in the electrocatalysts and their selectivity for CO2RTF and MOTF. Finally, we discuss the MOTF-coupled CO2RTF strategy and outline key challenges and future directions, highlighting pathways to accelerate the industrial utilization of this energy-efficient coelectrolysis approach.