Constructing electron-deficient octahedral cobalt active sites in roselike Ce-Co3O4 for ultrafast Fenton-like catalysis via electron transfer pathway

Abstract

Electron transfer process (ETP) represents an efficient and robust pathway in peroxymonosulfate (PMS) activation, yet its practical application is limited by sluggish kinetics, inefficient electron transport, and constrained catalyst suitability. Herein, we design a roselike Ce-doped Co₃O₄ catalyst (RL Ce-Co₃O₄) with electron-deficient Co sites to enable efficient PMS activation by a selective ETP pathway in spinel oxide. Atomic-level Ce incorporation in Co₃O₄ induces electron delocalization of octahedral cobalt (Co_Oh) via 3d-2p-4f coupling orbital, constructing electron-deficient Co_Oh active sites with depopulated 3d orbitals. The roselike architecture improves the accessibility of active sites to further promote the reaction kinetics. Mechanistic insight reveals that the electron-deficient Co_Oh sites enhance the adsorption and stabilization towards both PMS and bisphenol A (BPA) by intensified Co-O covalent interactions. Meanwhile, Ce doping improves the electrical conductivity of Co₃O₄, promoting rapid electron transfer from BPA to PMS* via a catalyst bridge, thereby disrupting the conventional Co²⁺/Co³⁺ redox cycling and establishing a catalyst-mediated ETP pathway. Synergistically, RL Ce-Co₃O₄ exhibits superior performance, achieving 99.9% BPA degradation within 3 min with a first-order knetic constant (k_obs) of 1.61 min⁻¹, and ultra-long-term stability (106 h) in a scaled-up reactor system. This work provides an innovative concept to unlock a selective, accelerated ETP pathway in spinel oxides.