CuO role in γ-Fe₂O₃-supported Pt–Cu bimetallic nanoparticles synthesized by radiation-induced reduction as catalysts for preferential CO oxidation

Modification of supported Pt catalyst by transition metal is effective for improving catalytic performance in fuel processing and electrochemical processes. In order to identify the role of CuO in Pt–Cu bimetallic nanoparticle catalyst in CO preferential oxidation in H₂-rich gas, three γ-Fe₂O₃-supported Pt–Cu catalyst samples consisting of Pt–Cu alloy with different CuO content were synthesized by a radiolytic process. By managing the concentrations of the copper source and oxygen dissolved in the precursor solution, the CuO content was successfully varied by an order of magnitude without changing the structure and composition of the Pt–Cu alloy. In the catalytic tests, CuO-promoted CO oxidation significantly at around 100 °C. The catalyst with the highest CuO content showed the highest CO and O₂ conversions. It was considered that the CuO phase promotes oxygen supply to CO chemisorbed on the Pt–Cu alloy surface. The alloy-CuO contact was suggested to be critical for the promoting effect.