Design of electrocatalysts and electrodes for CO2 electroreduction to formic acid and formate

Electrochemical carbon dioxide (CO₂) reduction reaction (CO₂RR) is gaining attraction as it enables the generation of highly valuable chemicals while mitigating greenhouse gas emissions. Numerous efforts have been dedicated to designing efficient catalysts that selectively reduce CO₂ into various chemicals such as formic acid/formate, carbon monoxide, methane, ethylene, and ethanol. The efficiency of the CO₂RR is evaluated through selectivity to the desired product, overpotential, current density, and stability. This work reviews emerging strategies to improve the CO₂RR performance to produce formate/formic acid by tuning catalyst and electrode structures. The catalyst-developing strategies are discussed in terms of engineering electronic and geometric structures, surface oxidation structure, and enlarging surface active area. The design of gas diffusion electrodes and reactor configuration, which are essential in enhancing the efficiency of the electrochemical system, are also mentioned. Finally, insights and perspectives are given on how to overcome the instability of catalysts and limitations of reactor designs.