Spatially Oriented S-Scheme and Schottky Junction in In2S3/Ti3C2/TiO2 Ternary Heterojunction for Efficient Photocatalytic H2 Production

The reasonable structural design and interfacial modification of heterojunction photocatalysts for accelerated charge separation and boosting photocatalytic activity remains a crucial challenge in solar-driven water splitting for H2 production. Herein, a hierarchical structured In2S3/Ti3C2/TiO2 ternary heterojunction was effectively constructed through a facile hydrothermal method integrated with a self-assembly strategy, in which Ti3C2 and TiO2 were loaded on the surface of hierarchical In2S3 microspheres assembled from nanosheets. In the photocatalytic system, the in situ electron paramagnetic resonance verifies that the photogenerated charge transfer between In2S3 and TiO2 obeys a typical S-scheme mechanism. Meanwhile, the introduction of Ti3C2 MXene as a conductive cocatalyst further promotes the separation and transfer of photogenerated charge through the formation of a Schottky junction, thus remarkably boosting the photocatalytic performance. Under simulated sunlight irradiation, the In2S3/Ti3C2/TiO2 ternary heterojunction exhibits a superior H2 production rate compared to pure TiO2 and In2S3. Moreover, the ternary heterojunction also displays outstanding stability after five consecutive cycling tests. This work highlights the synergistic integration of an S-scheme and Schottky junction in a ternary heterostructure for efficient charge separation, providing a feasible strategy for designing high-performance photocatalysts toward solar-driven H2 production.