Synthesis of magnetically recyclable FeCeO nanocrystals with heterojunction between Fe2O3 and CeO2 via one-step method toward efficient organic dyes degradation by activating peroxymonosulfate

Azo dye wastewater poses a serious threat to environment and human health due to steady structures make them resistant to biodegradation or chemical degradation. The coupling of photocatalysis and peroxymonosulfate (PMS) as an efficient strategy can achieve dye-contaminated water purification by inducing advance oxidation processes. In this study, magnetic FeCeO nanocrystals with heterojunction between Fe₂O₃ and CeO₂ by one-step method were successfully synthesized to efficiently degrade methyl orange (MO) and Congo red (CR) by activating PMS under visible light irradiation. PMS molecules could be adsorbed by Fe₂Ce₁O composite and generated ${\bullet SO}_4^{-}$ radicals during photocatalytic process. Free radical quenching experiments and electron paramagnetic resonance (EPR) revealed that ${\bullet SO}_4^{-}$ radicals were the dominant species in photodegradation process. Fe₂Ce₁O catalyst could completely decompose dye molecules for waste solutions with low dye concentration. Increasing MO and CR concentrations to 100 mg L⁻¹, the removal efficiencies of MO and CR by Fe₂Ce₁O were still up to 85.2% and 77.9% in sequence. And liquid chromatography mass spectrometry (LC-MS) was used to confirm the intermediates and degradation pathways during MO and CR degradation processes. Cyclic experiments demonstrated that Fe₂Ce₁O composite had good durability and reusability. Moreover, degradation mechanisms were investigated. This study provides new insight into the synthesis of heterogeneous metal oxide catalyst to solve the organic pollution issues.