Electrochemically deposited Sn catalysts with dense tips on a gas diffusion electrode for electrochemical CO2 reduction

The electrochemical CO2 reduction reaction (CO2RR) has undergone great advances recently. The gas diffusion electrode (GDE) has been introduced to enhance productivity. However, the studies on catalysts on the GDE are scarce, especially for the production of liquid products. Here, we deposited Sn electrocatalysts electrochemically with dense tips (SnDT) on a gas permeable carbon cloth electrode. The prepared cathode had a uniform surface covered with SnDT catalysts. We achieved a high specific production rate of the CO2RR towards formate, 1 mmol m(-2) s(-1), at only -0.76 V-RHE where partial current density and faradaic efficiency toward formate were -18.7 mA cm(-2) and 62.5%, respectively, in neutral electrolyte. Formate productivity of 65 mg h(-1) was achieved using a customized cell with 4 cm(2) of the SnDT GDE. Formate was stably produced for 72 h without changes in faradaic efficiency and current density. The product distribution was affected by local pH. The effect of catalyst shape was also investigated by comparing with commercial Sn nanoparticles deposited on a carbon cloth electrode.