Electrochemical, Scanning Electrochemical Microscopic, and In Situ Electrochemical Fourier Transform Infrared Studies of CO2 Reduction at Porous Copper Surfaces

There is significant interest in the design of high-performance electrocatalysts for efficient electrochemical reduction of CO2 to address the pressing environmental issue and climate change. Herein, a novel copper-aluminum nanostructured catalyst is fabricated via an alloying/dealloying technique. The effect of the initial alloy's elemental composition and subsequent dealloying, via HCl acid treatments, on the stability and activity of the catalyst for electrochemical CO2 reduction is studied. The optimized porous catalyst shows high catalytic activity for the electrochemical CO2 reduction reaction (CO2RR) with current efficiencies achieving greater than 81%. Gas and liquid product analysis confirms the formation of CO, H2, and HCOO-. Scanning electrochemical microscopy was employed to monitor the activity of the catalyst and the CO2RR products. In situ electrochemical FTIR spectroscopic studies revealed the first CO2RR intermediate was carbon-bound to the acid-treated 50:50 Cu/Al (at. %) alloy surface in a monodentate orientation. The synthetic approach reported in the present study leads to a new promising electrocatalyst with superior catalytic activity and high efficiencies for the effective electrochemical reduction of CO2 to valuable products.