Nonstoichiometric Copper Bismuth Oxide Catalyst Boosting Surface-Bound Cu(III)-Peroxo Intermediate for Selective Oxidation via Dark Peroxydisulfate Activation

While high-valent copper intermediates are pivotal for efficient peroxydisulfate (PDS) activation, their generation and role in heterogeneous catalysis remain unclear. Herein, we demonstrate that a nonstoichiometric Cu 0.84 Bi 2.08 O 4 catalyst enables the dark activation of PDS via a novel pathway dominated by a surface-bound Cu(III)-peroxo intermediate ( ≡ Cu(III)-O−O−SO 3 ). A suite of spectroscopic and chemical probes revealed that this Cu(III)-peroxo species, along with superoxide radicals (•O 2 − ), acts as the primary oxidant, enabling the highly selective and rapid degradation of bisphenol A (BPA) and other phenolic pollutants. Furthermore, H 2 O 2 generated from PDS hydrolysis synergistically participates in the reaction, accounting for the exceptionally high PDS utilization efficiency of the system. The system exhibits remarkable robustness, maintaining high activity over a wide pH range (4–11) and demonstrating strong resistance to interference from ions. This study elucidates a distinct Cu(III)-peroxo-mediated mechanism and offers a new strategy for designing highly selective catalysts for environmental remediation.