SrTiO₃/Ti₃C₂T_x Schottky heterojunction as a promising high-efficiency photocatalyst for H₂ evolution

Exploring low-cost, high-efficiency, and stable photocatalysts is still a significant challenge. SrTiO3, one of the appealing photocatalysts, can meet most of the screening criteria except for its efficiency, which is restricted by its poor absorption of visible light and its prompt photogenerated carrier recombination. Recently, a two-dimensional transition metal carbide Ti3C2Tx (2D MXene) has been found to serve as a co-catalyst due to its excellent metallic conductivity, hydrophilic property, large specific surface area, abundance of active sites, and low reaction barrier to hydrogen production. In this work, SrTiO3 nanoparticles are rationally integrated with Ti3C2Tx nanosheets via a simple hydrothermal process. The hydrogen production rate can achieve up to 3.43 mmol g−1 h−1 in the hybridization of SrTiO3-3 wt. % Ti3C2Tx, which is almost six times that of SrTiO3 alone. This remarkable enhancement arises predominantly from the Schottky contact between SrTiO3 and Ti3C2Tx, which can effectively suppress the recombination of photogenerated carriers and accelerate their separation. In addition, such enhancement benefits from the hydrogen evolution capacity of Ti3C2Tx. This work opens an excellent prospect for constructing highly active, low-cost, and stable photocatalysts with 2D MXene and finding potential applications of 2D MXene in energy conversion fields.