Structural, magnetic, and photocatalytic properties of core-shell reversal nanocomposites of titanium-doped strontium ferrite and silica

This paper presents the effect of core-shell reversal on the photocatalytic potential of titanium-doped strontium ferrite (Sr0.4Ti0.6Fe2O4.6) and silica (SiO2) nanocomposites. The construction of core-shell-structured Z-scheme systems is a valid strategy to effectively enhance photocatalytic activity. Mossbauer spectroscopy studies demonstrated the more lowering of hyperfine field values for SiO2@Sr0.4Ti0.6Fe2O4.6 compared to Sr0.4Ti0.6Fe2O4.6@SiO2 core-shell nanocomposite. The Sr0.4Ti0.6Fe2O4.6@SiO2 nanocomposite had higher BET-specific surface area of 117.3 m2/g than that of SiO2@Sr0.4Ti0.6Fe2O4.6(106.9 m(2)/g). The Sr0.4Ti0.6Fe2O4.6@SiO2 exhibited higher photocatalytic activity than SiO2@Sr0.4Ti0.6Fe2O4.6 for the degradation of model pesticide, pendimethalin (similar to 96%). It was ascribed to the narrowing of bandgap, high surface area, and decrease in the photoluminescence intensity. A Z-scheme photocatalytic degradation mechanism for pendimethalin over Sr0.4Ti0.6Fe2O4.6@SiO2 nanocomposite was proposed. The results indicate that the designing of core-shell structures can play a significant role in improving the photocatalysts.