Visible-Light-Driven Peroxymonosulfate Activation by Multiphase Fe2cu1cexo Composite Catalyst for Efficient Removal of Organic Pollutions

Abstract

The band structures of polyvalent metal oxides are well-suited for visible-light-induced catalysis. However, the lower charge carrier separation efficiency of single metal oxide as catalyst significantly limits its photocatalytic activity. In this work, a novel multi-heterojunction construction strategy was proposed. Based on the oxidation temperature differences between Ce3+ and Fe3+/Cu2+ ions, as well as their atomic radius mismatch, we innovatively developed a high-temperature gradient oxidation strategy by introducing Ce into the Fe-Cu-O spinel system, and successfully fabricating a multi-heterojunction Fe2Cu1CexO catalyst containing Fe2O3, CuO, Cu0.75Fe2.25O4, and CeO2 components. Fe2Cu1CexO heterojunctions establish built-in electric fields at multi-phase interfaces, efficiently facilitating electron-hole pairs separation and enhancing photocatalytic performance. Although Fe2Cu1O matrix demonstrates strong visible-light absorption, strategic incorporation of Ce element further amplifies light harvesting capacity while improve photoelectrochemical properties. Notably, Fe2Cu1Ce0.5O achieves exceptional photocatalytic through synergistic effects between different semiconductors, exhibiting 92.0% tetracycline hydrochloride (TCH) degradation efficiency in the Fe2Cu1Ce0.5O/PMS/vis system. The system also exhibits robust removal capabilities for organic dyes, eliminating 88.5% methyl orange (MO, 120 mg L-1) and 92.5% Congo red (CR, 100 mg L-1). The superior photodegradation performance is primarily attributed to the enhanced activation of peroxymonosulfate (PMS) by Fe2Cu1Ce0.5O composite under visible light irradiation. During the catalytic process, PMS not only serves as the precursor for sulfate radical ( ) generation but also facilitates the dynamic valence cycling of polyvalent metal ions (Ce3+/Ce4+ and Fe2+/Fe3+), thereby enabling a self-sustaining catalytic mechanism. This study proposes a novel strategy for designing heterogeneous metal oxide heterojunction catalysts, offering an effective solution to mitigate persistent organic pollution through advanced oxidation processes.

Keywords: Heterojunction, Visible-light photocatalysis, Polyvalent metal oxides, PMS activation, Organic pollutant degradation.