Polyethylene Glycol Covered Sn Catalysts Accelerate the Formation Rate of Formate by Carbon Dioxide Reduction

Abstract

Accelerating the CO2-recycling process is crucial for preventing global warming. Electrochemical reduction allows the efficient conversion of CO2 into useful chemical compounds with catalysts. During the electrolytic synthesis of CO2, an increase in voltage accelerates the synthesis of the target product and enhances byproduct formation. Previously investigated electrocatalysts do not increase the formation rate with parameter tuning. Herein, we report the development of a polymer-covered Sn catalyst using CO2-absorbable polyethylene glycol (PEG) polymers for the electrochemical reduction of CO2. The catalyst demonstrates high Faradaic efficiencies and doubles the formation rate at -1.2 V (vs RHE) in comparison with that of Sn catalysts. A mechanistic investigation using density functional theory suggests that PEG captures the CO2 molecules and, subsequently, the adsorbed CO2 molecules are transferred to the underlying Sn surface with a low energy barrier. Tuning of the PEG density is vital for a continuous CO2 capture and transfer mechanism that can enhance the catalytic activity.