Electrochemical Reduction of Carbon Dioxide to Formate on Palladium-Copper Alloy Nanoparticulate Electrode

The bimetallic alloy nanoparticle catalysts composed of Pd and Cu were synthesized for electrochemical reduction of CO2. The effect of the catalyst composition on the CO2 reduction activity and the selectivity was investigated, and at the high Pd/Cu ratio CO2 reduction to formate rather than hydrogen evolution proceeded predominantly. The combination of Pd with Cu also changed the stability of the catalyst. By using the bimetallic catalyst, stable reduction current was obtained in the long-term electrolysis while a monometallic Pd catalyst suffered from deactivation due to poisoning by CO. These improvements are attributable to the electrical interaction between Pd and Cu. The resultant lowering shift of a d-band center reduced binding strength of CO, leading to the achievement of stable reduction of CO2 with a small overpotential.