Electrocatalytic Reduction of Gaseous CO 2 to CO on Sn/Cu‐Nanofiber‐Based Gas Diffusion Electrodes

Earth‐abundant Sn/Cu catalysts are highly selective for the electrocatalytic reduction of CO 2 to CO in aqueous electrolytes. However, CO 2 mass transport limitations, resulting from the low solubility of CO 2 in water, so far limit the CO partial current density for Sn/Cu catalysts to about 10 mA cm −2 . Here, a freestanding gas diffusion electrode design based on Sn‐decorated Cu‐coated electrospun polyvinylidene fluoride nanofibers is demonstrated. The use of gaseous CO 2 as a feedstock alleviates mass transport limitations, resulting in high CO partial current densities above 100 mA cm −2 , while maintaining high CO faradaic efficiencies above 80%. These results represent an important step toward an economically viable pathway to CO 2 reduction.