Selective Electrochemical Conversion of CO₂ to Formate via Redox-Modulated Porous Metal Electrodes Coupled with Efficient Oxygen Evolution

The electrochemical conversion of carbon dioxide (CO2) to formate holds significant promise for CO2 mitigation and as a foundational process for various crucial chemicals. However, the efficiency of this conversion process is hindered by the sluggish kinetics of the counter oxygen evolution reaction (OER). In this study, we explore the impact of redox modulation in dendritic lead (Pb) doped tin (Sn) catalysts to enhance the Faradaic efficiency of CO2 reduction to formate, achieving an impressive Faradaic efficiency of 92.5% and a cathodic energy efficiency of 75%. Moreover, Iron cobalt layered double hydroxide (CoFeLDH) grown on hierarchically porous nickel acts as a standout performer for the OER, demonstrating a remarkably low overpotential of 90 mV at 50 mA cm–2, accompanied by a high electrochemical surface area of 684.25 cm2. Integration of these cost-effective catalysts into a two-electrode electrolyzer enables simultaneous reduction of CO2 to formate and water oxidation to oxygen, exhibiting exceptional activity, stability, and efficiency, with an overall bias as low as 2.56 V required to achieve a current density of 25 mA cm–2. This study represents a significant advancement in sustainable CO2 conversion technologies, offering promising avenues for carbon utilization and renewable energy generation.