Zr–Cu oxide heterostructures with introduced defects for efficient oxygen reduction reaction

Abstract

Creating an oxygen reduction reaction (ORR) electrocatalyst with outstanding performance is crucial for advancing green energy storage and conversion technology. In this experiment, Zr–Cu oxide heterostructure nanocomposite catalysts, ZrO₂–Cu₂S/C and ZrO₂–Cu_1.93S/C, were successfully synthesized by vulcanizing ZrO₂–Cu₂(OH)₂CO₃/C and introducing defect engineering. The catalysts were thoroughly examined using various testing methods to determine their structures, and their catalytic performance in ORR was assessed. ZrO₂ forms heterostructures with Cu₂S and Cu_1.93S, which are evenly dispersed on the carbon carrier. In an alkaline medium, both catalysts display excellent ORR activity. The ZrO₂–Cu_1.93S/C catalyst exhibits the highest ORR activity, with an onset potential of 0.90 V and a half-wave potential of 0.75 V (vs. RHE) in 0.1 M KOH. The limiting diffusion current density is measured at 3.25 mA cm⁻². The DFT theoretical calculation indicates that electrons are redistributed and accumulated at the heterojunction interface, presenting a stronger electron-donating ability and a faster electron conduction ability. Both vulcanization and the introduction of defects play an important role in enhancing the ORR performance of the catalyst. This study provides an ORR catalyst with excellent performance and opens up a new direction and idea for the research of Zr–Cu oxide composite electrocatalysts.