Novel photocatalytic SrTiO₃@TiO₂/SrSO₄ heterojunction and its high performance in RhB degradation

Building a heterogeneous structure is favorable for improving the performance of photocatalyst materials. In this study, we fabricated a ternary SrTiO₃@TiO₂/SrSO₄ heterojunction material with a porous shell composite structure via a simple one-step direct high-temperature treatment using the commercial strontium titanate and ZnSO₄. The effect of the synthesis temperature on the ZS-STO-T products was investigated. Results indicated that the prepared ZS-STO-550 had a special structure with the SrTiO₃ particles encapsulated by porous TiO₂ shells (SrTiO₃@TiO₂), hollow porous TiO₂ shells (void@TiO₂), and SrSO₄ particles, interweaving with each other to form the SrTiO₃@TiO₂/SrSO₄ heterostructure. Hence, the ZS-STO-550 exhibited superior photocatalytic performance with the fastest degradation rate, degrading 98.90% of Rhodamine B (RhB) within just 24 minutes. Moreover, the degradation rate of RhB was still 92.53% after ZS-STO-550 was repeatedly used for 5 times. The construction of the ternary SrTiO₃@TiO₂/SrSO₄ heterojunction is promising for the practical use of SrTiO₃ photocatalyst materials.