Work

Enriched Oxygen Vacancy‐Mediated Efficient Charge Transfer in S‐Scheme ZnO‐V O @Zn 0.5 Cd 0.5 S Heterojunction for Rapid U(VI) Removal From Nuclear Wastewater

Year: 2025

Type: article

Abstract: Efficient charge separation is critical for high‐performance photocatalytic reduction of U(VI) in nuclear wastewater. Employing defect engineering, an oxygen vacancy (V O )‐enriched S‐scheme ZnO‐V O @Zn 0.5 Cd 0.5 S (ZnO‐V O @ZCS) heterojunction is constructed for rapid U(VI) removal. The synergistic effect of oxygen vacancies and the S‐scheme mechanism is shown to significantly enhance charge separation and photocatalytic U(VI) reduction. Remarkably, ZnO‐V O @ZCS achieves 99.10% U(VI) removal within 10 min at pH 4 under simulated sunlight without sacrificial agents, surpassing the V O ‐free ZnO@ZCS reference and exhibiting 4.10‐fold and 20.0‐fold higher activity than pristine ZnO‐V O and ZCS, respectively. Meanwhile, the catalyst maintains robust performance across a wide pH range (3–8), complex matrices (interfering ions/dyes), natural sunlight, and diverse U(VI) containing wastewater. In situ X‐ray photoelectron spectroscopy (In situ XPS) and Kelvin probe force microscopy (KPFM) confirm the S‐scheme charge transfer between ZnO‐V O and ZCS. Femtosecond transient absorption spectroscopy (fs‐TAS) and density functional theory (DFT) calculations reveal that V O serve as transient electron traps, creating rapid charge‐transfer channels that interplay with the S‐scheme to enhance charge transfer efficiency and accelerate U(VI) reduction kinetics. This study provides new insights for designing defect‐modulated S‐scheme heterojunction photocatalysts, promising for sustainable nuclear wastewater treatment.

Source: Advanced Science

DOI: 10.1002/advs.202512163