Electrohydrogenation of Carbon Dioxide using a Ternary Pd/Cu 2 O–Cu Catalyst

Abstract A simple one‐pot method has been developed to synthesize a palladium/cuprous oxide‐copper (Pd/Cu 2 O–Cu) material with a well‐defined structure, by modification of Cu 2 O–Cu with Pd through a galvanic replacement reaction. Compared with the well‐known copper/cuprous oxide (Cu/Cu 2 O) catalysts, the Pd/Cu 2 O–Cu material can catalyze the electroreduction of CO 2 into C 1 products with much higher faradaic efficiencies at lower overpotentials in a CO 2 ‐saturated 0.5 m NaHCO 3 solution. In particular, the highest faradaic efficiencies of 92 % for formate and 30 % for methane were achieved at −0.25 and −0.65 V (vs. the reversible hydrogen electrode), respectively. The improvement is suggested to be the result of a synergistic effect between PdH and the catalytically active copper sites during electrochemical CO 2 reduction.