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

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/Cu1-xAlxCo2O4 structure. Compared to lattice-confined Cu2+, the surface Cu0 continuously supplied delocalized electrons to 3dyz 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-3dyz and O-2py 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.