Insights on Hetero-Nanostructured CuO-Cu_xCe_yO_z/C Catalyzed Oxygen Reduction Reaction

The stupendous challenge of developing a functional and cost-effective electrocatalyst toward oxygen reduction reaction (ORR) persists. Our strategy includes integration of CeO₂ into the carbon-supported CuO. This integration leverages the distinctive 4f electron configuration of cerium, which facilitates dynamic oxygen adsorption and desorption. The Ce^{3 +}/Ce^{4 +} redox couple plays a pivotal role in this mechanism, enabling the catalyst to effectively manage oxygen in varying environmental conditions. Specifically, the redox cycling between Ce^{3 +} and Ce^{4 +} enhances the formation of oxygen vacancies and improves oxygen mobility within the catalyst structure. The CuO-Cu_xCe_yO_z/C catalyst exhibits synergistic catalytic effect between CuO-Cu_xCe_yO_z by enhancement of its activity toward ORR with a more positive onset potential E_onset of 0.78 V versus RHE than its counterparts, in alkaline medium. Moreover, the catalyst delivers a highly stable ORR performance that is, 78.7%, which is comparable to the commercial Pt/C with high mass activity and limiting current density. The study provides an insight into structure-activity correlation and highlights the inclusion of rare earth metals with transition metal oxides as a potential catalyst for ORR.