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. Mӧssbauer 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 m2/g). The Sr0.4Ti0.6Fe2O4.6@SiO2 exhibited higher photocatalytic activity than SiO2@Sr0.4Ti0.6Fe2O4.6 for the degradation of model pesticide, pendimethalin (∼ 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.Graphical abstract: