Interfacial V ⁵⁺ /V ⁴⁺ Redox Kinetics Enabling Fe-free Photo-Fenton Catalysis in α-V ₂ O ₅ -ACNT Nanohybrids for Efficient Removal of Mixed CBZ and DFN

High Resolution Image Download MS PowerPoint Slide Efficient removal of structurally diverse and persistent pharmaceutical contaminants from wastewater, particularly in mixed-pollutant systems, remains a critical challenge in advanced water treatment technologies. Conventional Fe-based photofenton systems suffer from iron (Fe) sludge generation and secondary metal contamination, limiting their practical and sustainable application. Herein, we report Fe-free photofenton catalysis enabled by interfacial V 5+ /V 4+ redox kinetics in α- V 2 O 5 -decorated activated carbon nanotube (α-V 2 O 5 -ACNT) nanohybrids for simultaneous removal of two emerging pharmaceutical pollutants, diclofenac (DFN) and carbamazepine (CBZ), from their mixed system. Electronic coupling at the V 2 O 5 /ACNT interface promotes rapid charge separation, abundant oxygen vacancies, and dynamic V 5+ /V 4+ redox cycling, which efficiently activates H 2 O 2 to generate highly reactive • OH radicals without the need for Fe species. Under optimized conditions, the catalyst achieved ∼96% removal efficiency for DFN and ∼95% against CBZ within 60 min. Transient photocurrent, EPR/ESR, and radical trapping analyses confirm improved charge transport and intensified • OH generation. Density functional theory calculations further reveal favorable adsorption geometries, charge redistribution, and reactive site localization of both pollutants on defect-rich surfaces, rationalizing the observed removal pathways. This study establishes mechanistic synergy between V 2 O 5 and ACNTs as an effective strategy for designing sustainable, Fe-free photofenton systems.