Tailoring Copper Foam with Silver Dendrite Catalysts for Highly Selective Carbon Dioxide Conversion into Carbon...

The present study outlines the important steps to bring electrochemical conversion of carbon dioxide (CO₂) closer to commercial viability by using a large-scale metallic foam electrode as a highly conductive catalyst scaffold. Because of its versatility, it was possible to specifically tailor three-dimensional copper foam through coating with silver dendrite catalysts by electrodeposition. The requirements of high-yield CO₂ conversion to carbon monoxide (CO) were met by tuning the deposition parameters toward a homogeneous coverage of the copper foam with nanosized dendrites, which additionally featured crystallographic surface orientations favoring CO production. The presented results evidence that Ag dendrites, owing a high density of planes with stepped (220) surface sites, paired with the superior active surface area of the copper foam can significantly foster the CO productivity. In a continuous flow-cell reactor setup, CO Faradaic efficiencies reaching from 85 to 96% for a wide range of low applied cathode potentials (<1.0 V_RHE) along with high CO current densities up to 27 mA/cm² were achieved, far outperforming other tested scaffold materials. Overall, this research provides new strategic guidelines for the fabrication of efficient and versatile cathodes for CO₂ conversion compatible with large-scale integrated prototype devices.