Direct formation of dendritic Ag catalyst on a gas diffusion layer for electrochemical CO₂ reduction to CO and H₂

Dendritic Ag (a CO₂-to-CO reduction catalyst) has been synthesized on carbon paper (CP) using pulse electrodeposition to fabricate a gas diffusion electrode. A combination of sonication and pulse deposition facilitated mass transfer of Ag ions to the CP, enlarging the catalyst active surface area without significantly changing the Ag crystalline structure. The current density of CO₂ reduction was proportional to the surface area of dendritic Ag. Further improvements in performance were achieved by adding polyethylene glycol to the CO₂ reduction cell catholyte that removed the CO gas bubbles produced at the electrode surface. The fabrication methods presented herein suggest an effective gas diffusion electrode for application in the membrane-electrode-assembly-type single cell for electrochemical CO₂ reduction.