Electron-rich CuO_x@Al₂O₃ Catalyst for Sustainable O₂ Activation in Fenton-Like Reactions

Molecular oxygen (O₂) activation is pivotal in advancing green chemistry and catalysis, addressing processes such as energy conversion and environmental remediation. However, the inherent inertness of the O₂ necessitates highly efficient catalysts. In this study, an electron-rich CuO_x@Al₂O₃ catalyst with high metal loading and dispersion was synthesized via the ion-exchange inverse-loading method. The novel CuO_x@Al₂O₃ significantly enhanced O₂ activation due to the accelerated Cu⁰ → Cu⁺ → Cu²⁺ redox cycle, achieving the 85% chlorobenzene removal in Fenton-like reaction. This is substantially higher than the chlorobenzene removal observed with conventional CuO_x/Al₂O₃ (45%). Experiments and density functional theory (DFT) calculations revealed that Cu-Cu sites over CuO_x@Al₂O₃ greatly facilitated charge transfer, weakened O-O bonds, and promoted synergistic O₂ and H₂O₂ activation to produce ^•OH and O₂^•-, thereby enhancing oxidants utilization efficiency. This study provides a sustainable pathway for pollutant degradation by achieving O₂ activation and offers valuable insights for designing advanced Cu-based catalysts in green oxidation processes and environmental remediation.