Understanding the synergetic catalytic functions of Cu–Pt active sites in the bimetallic CuPt/ZrO2 catalyst in CO oxidation

Abstract

Catalytic oxidation processes for carbon monoxide (CO) typically rely on catalysts made from noble metals. However, due to the scarcity and high cost of noble metals, developing low–cost, highly active, and stable catalysts with low noble metal loading is highly demanded but challenging. Herein, we synthesized ZrO₂–supported CuPt alloy nanoparticle (NP) catalyst (0.3Cu0.1Pt/ZrO₂), with a Cu loading of 0.3 wt% and a Pt loading of 0.1 wt%, using a straightforward impregnation method. This catalyst structure enables the well-mixing of Cu and Pt atoms in the pristine and partially oxidized catalysts during the CO oxidation. The temperature for 0.3Cu0.1Pt/ZrO₂ to reach 90 % CO conversion is 160 °C, which is much lower than those for 0.1Pt/ZrO₂ (220 °C) and 0.4Cu/ZrO₂ (195 °C). Extensive characterizations were conducted, particularly for the pristine catalysts. The experiments and density functional theory (DFT) calculations results reveal that the interaction between the two metals significantly modified the electronic property of the catalyst. On CuPt bimetallic sites, the electron transfer from Cu to Pt weakens the strong adsorption of CO, and Cu species provide sites for O₂ adsorption, which synergistically promotes the CO oxidation on the surface of CuPt NPs. This research provides deep insights into the relationship between the catalyst structure and their catalytic performance and paves the way for developing highly active bimetallic synergistic catalysts for CO oxidation.