Band gap engineering and performance enhancement of spinel ferrite via Indium doping for efficient solar-driven remediation of difenoconazole
摘要
Persistent agrochemicals, such as difenoconazole, pose significant environmental challenges because of their resistance to conventional water treatment. This study investigates indium-doped strontium aluminum ferrite, Sr1InXAl0.5−XFe1.5O4 (x = 0–0.5), as a visible-light-responsive photocatalyst for difenoconazole degradation and establishes clear structure–property-performance correlations through targeted doping. Spinel ferrite nanoparticles were synthesized via a sol–gel auto-combustion method and comprehensively characterized using XRD, FTIR, Brunauer–Emmett Teller, SEM, UV–visible spectroscopy, and DC resistivity measurements. Optimal In3+ doping (x = 0.4) induced lattice contraction (8.348 to 8.305 Å), reduced the crystallite size by 20.1% (28.3 to 22.62 nm), increased the BET surface area by 23.9% (17.15 to 21.25 m2 g−1), and narrowed the band gap from 2.84 to 2.67 eV. Under simulated solar irradiation, the optimized catalyst achieved complete degradation of 10 ppm difenoconazole within 50 min, following second-order kinetics (k = 0.01138 L mg−1 min−1, R2 = 0.9929). The photocatalytic efficiency was enhanced by a 57.7% increase in the quantum yield (1.05 × 10−6 molecules photon−1), with radical scavenging experiments identifying hydroxyl radicals (•OH) as the dominant reactive species (74% contribution). The catalyst demonstrated excellent stability, retaining 84.65% of its activity after five consecutive cycles. These findings highlight the potential of compositionally engineered spinel ferrites as efficient, magnetically recoverable, and reusable photocatalysts for sustainable solar-driven water remediation applications.