CO2-to-HCOOH Electrochemical Conversion on Nanostructured CuxPd100-x/Carbon Catalysts.

Selective electrochemical conversion of CO₂ to HCOOH is obtained at the surface of a carbon-supported bimetallic cathode material composed of copper and palladium nanoparticles. Polycrystalline copper or large copper particles are well-known to catalyze CO₂ reduction to hydrocarbons at relatively negative potentials, or when their surface is covered by copper oxides (Cu₂O and CuO). Cu-based materials modified by various palladium contents (0< × <100), were synthesized by using the microwave-assisted polyol method to serve as a cathode in the selective CO₂-into-HCOOH transformation. Herein, we developed a targeted preparation route toward the metal content/catalytic activity relationship correlating atomic ratio with faradaic efficiency (FE) to formate formation (ca. 60% FE) at - 0.72 V vs. RHE, which represents a 703 mV overpotential at pH=7. Consequently, the occurrence of this reduction reaction slows down the parallel H₂ production from the solvent consumption, while the neighboring Cu- Pd provides excellent activity and a good efficiency toward CO₂ reduction via the hydridation of the CO₂ molecule to orientate the reaction to formate rather than carbon monoxide or H2 evolution. [ABSTRACT FROM AUTHOR]