Oxygen reduction reaction (ORR) kinetics is critically dependent on the precise modulation of the interactions between the key oxygen intermediates and catalytic active sites. Herein, a novel electrocatalyst is reported, featuring nitrogen-doped carbon-supported ultra-small copper oxide nanoparticles with the broken-symmetry C4v coordination filed sites, achieved by a mild γ-ray radiation-induced method. The as-synthesized catalyst exhibits an excellent ORR activity with a half-wave potential of 0.873 V and shows no obvious decay over 50 h durability in alkaline solution. This superior catalytic activity is further corroborated by the high-performance in both primary and rechargeable Zn-air batteries with an ultrahigh-peak-power density (255.4 mW cm-2) and robust cycling stability. The experimental characterizations and density functional theory calculations show that the surface Cu atoms are configured in a compressed octahedron coordination. This geometric arrangement interacts with the key intermediate OH*, facilitating localized charge transfer and thereby weakening the Cu─O bond, which promotes the efficient transformation of OH* to OH- and the subsequent desorption, and markedly accelerates kinetics of the rate-determining step in the reaction. This study provides new insights for developing the utilization of γ-ray radiation chemistry to construct high-performance metal oxide-based catalysts with broken symmetry toward ORR.
Keywords: copper oxide catalyst; electrocatalysis; irradiation synthesis; local broken‐symmetry; oxygen reduction reaction.
© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.