Construction of TiO2/SrTiO3 Heterojunction Derived from Monolayer Ti3C2 MXene for Efficient Photocatalytic Overall Water Splitting

Construction of heterojunction at the atomic scale to ensure efficient charge separation for improvement of photocatalytic water splitting is challenging. Herein, a facile hydrothermal method has been applied for the in situ fabrication of TiO2/SrTiO3 heterojunction, using the monolayer Ti3C2 MXene as the template and reactant. It is found that the sample with the hydrothermal reaction time of 60 min exhibits the highest H-2 evolution rate with the sacrificial reagent, due to the efficient charge separation of TiO2/SrTiO3 heterojunction as Ti3C2 derivative. In addition, the sample shows the best overall water splitting performance at a hydrothermal reaction time of 120 min, where TiO2 is nearly converted to SrTiO3, due to the fast kinetic process and low structural defects of SrTiO3. This work not only provides a simple strategy for the fabrication of heterojunction photocatalysts but also demonstrates the difference in optimization of half-reaction and overall water splitting reaction.