Regulating phenoxyl radical-mediated advanced oxidation processes via CuO-CeO heterostructure engineering for sustainable water purification.

Harnessing inherent organic pollutants in wastewater to drive self-accelerated Fenton-like degradation establishes a sustainable water purification paradigm, wherein the central challenge centers on strategically regulating catalyst-pollutant interaction to optimize phenoxyl radical formation and leverage its inherent catalytic synergy. Here, we demonstrate that a CuO-CeO heterostructure combining Cu(II) active centers with Ce(IV) electron reservoirs achieves unprecedented enhancement in phenoxyl radical generation efficiency. This breakthrough arises from two synergistical mechanisms: strong metal-support interaction (SMSI) elevates the d-band center of Cu to thermodynamically favor spontaneous electron abstraction from pollutants, while the electron buffering capability of CeO accelerates the Cu(II)/Cu(I) redox cycle for efficient active site regeneration. The optimized CuO-CeO/persulfate (PDS) system exhibits 19.2-fold enhanced kinetic constant (k) for p-chlorophenol (4-CP) degradation compared to the CuO/PDS counterpart, alongside remarkable pH versatility across 3.5-10. Crucially, the phenoxyl radical-mediated oxidation demonstrates exceptional operational stability with consistent 100 % 4-CP removal over eight consecutive cycles, contrasting sharply with the 56.3 % efficiency decline observed in CuO. This work establishes a strategic framework for advancing phenoxyl radical-mediated AOPs (PR-AOPs) toward sustainable water purification technologies.