A novel strontium carbonate/strontium sulfate/strontium titanate composite with core shell structure for photocatalytic degradation of dyes

•A novel catalyst SrTiO3-SrSO4-SrCO3 with core–shell structure was prepared.•TSC showed better photocatalytic performance over degradation of MB than pure SrTiO3.•The photocatalytic performance was due to efficient transport of carriers in TSC composite. A core–shell structure SrSO4-SrCO3 (SSO-SCO) composite was synthesized with strontium titanate and ammonium carbonate. The SrTiO3-SrSO4-SrCO3 (TSC) composite with core–shell structure was obtained by adding strontium titanate into the mixture through hydrothermal method. The morphology, elemental composition and crystallinity of the catalyst were characterized by SEM, EDS, TEM and XRD analyses. The TSC composite exhibited excellent photocatalytic performance for the degradation of methylene blue dyes compared to the SrTiO3. The high catalytic efficiency was due to synergistic effect of the increased light harvesting and efficient transport of photogenerated electron and hole pairs in composites based on the results of UV–vis and PL and transient photocurrent response tests. Furthermore, ESR spectra showed that ·OH radicals and hole radicals were the main active species contributing to the excellent performance. Based on the photocatalytic results and ESR spectra, a photocatalytic mechanism for MB degradation was proposed.