Fabrication of Ti3C2/TiO2/SrTiO3 ternary heterojunction photocatalyst with efficient charge separation for enhanced hydrogen evolution

In this work, a ternary Ti3C2/TiO2/SrTiO3 composite with heterogeneous network structure was prepared by two-step in situ hydrothermal synthesis method, which mainly involved the growth of TiO2 nanosheets and fibrous SrTiO3 sequentially on the Ti3C2 substrate using the Ti source inherent in Ti3C2 as the reaction site. The Ti3C2/TiO2/SrTiO3 heterojunction exhibited enhanced photocatalytic hydrogen evolution activity. When the doping amount of SrTiO3 was 5 wt%, the hydrogen evolution rate of 5MTS under full solar irradiation reached 14322.6 μmol·g−1·h−1, which was 10.6 times the rate of the Ti3C2/TiO2 composite without modified SrTiO3. Meanwhile, the 5MTS composites showed good stability in the photocatalytic hydrogen evolution cycle test. The enhanced activity and recyclability are mainly attributed to the strong light absorption ability, fast separation of photogenerated electron-hole pairs, and abundant catalytic active sites. In addition, the synthesis method utilizing an intrinsic Ti source also enhances the interfacial contact between Ti3C2, TiO2, and SrTiO3. This study provides an effective reference for the construction of perovskite-based or Ti3C2 co-catalyzed heterostructures and their application for the conversion of solar power to hydrogen energy.