Reconstructing lattice Cu²⁺ to surface Cu⁰ in CuCo spinel drives reverse charge transfer for selective peracetic acid...

Peracetic acid (PAA)-based advanced oxidation processes hold great promise in wastewater decontamination, but how to precisely regulate the composition of generated reactive species to meet complex realistic water matrices remains challenging. Here we report an exclusion-anchoring strategy to thermodynamically drive the Cu²⁺ species out of CuCo₂O₄ lattice by Al³⁺ ions to form the reconstructed Cu⁰/Cu_1-xAl_xCo₂O₄ structure. Compared to lattice-confined Cu²⁺, the surface Cu⁰ continuously supplied delocalized electrons to 3d_yz orbital of active Co sites, significantly accelerating the crucial Co(III)/Co(II) redox kinetics. Moreover, this unique configuration effectively stabilized the low-spin state of Co, inducing reversed electron transfer from Co to PAA via effective Co-3d_yz and O-2p_y orbital hybridization, which lowered the activation barrier of O-O bond to 0.03 eV, and altered pathway to selectively produce acetylperoxyl (CH₃C(O)OO•) and singlet oxygen (¹O₂). In contrast to •OH generated in traditional CuCo₂O₄, the synergistic CH₃CO(O)O• and ¹O₂ species selectively attack electrophilic, nucleophilic, and radical-sensitive sites of organic pollutants, significantly enhancing degradation efficiency, including a 19.7 times enhancement in tetracycline degradation rate. Moreover, the inherent synergistic radical and non-radical pathway enables high robustness in complex water matrices and exceptional reusability. This study provides a new electronic scale insight for precise designing spinel-based catalysts toward wastewater purification.