Internal electric field triggered charge redistribution in CuO/Fe2O3 composite to regulate the peroxymonosulfate activation for enhancing the degradation of organic pollutants

Herein, we adopt a feasible method to synthesize the CuO/Fe 2 O 3 composite with heterostructure. Owing to the significant differences in work functions, an internal electric field is built at the interface of heterojunction after the combination of CuO with Fe 2 O 3 , which can reduce interface resistance and accelerate charge transfer. Interestingly, under the induction of electrostatic interaction provided by internal electric field, the CuO/Fe 2 O 3 composite will form electron-rich and electron-deficient active zones. More importantly, the peroxymonosulfate (PMS) can be oxidized by the CuO with electron-deficient active zone to generate SO 5 •‒ , subsequently converting into 1 O 2 . Meanwhile, the Fe 2 O 3 component with electron-rich active zone can provide electrons for PMS to achieve the heterolysis of Fe-O-O, thereby producing the high-valent metal complex (namely ≡ Fe 5+ =O). Consequently, the CuO/Fe 2 O 3 -2-mediated PMS system with good anti-interference ability displays excellent performance in wastewater treatment. Benefiting from the electrophilic reaction of 1 O 2 and ≡ Fe 5+ =O, various typical organic pollutants can be ultimately mineralized into CO 2 , H 2 O and other nontoxic by-products by the CuO/Fe 2 O 3 -2-mediated PMS system. In short, current work shares some novel insights into the effect of internal electric field on PMS activation, which can provide valuable references for future research.