The photocatalytic efficiency of monolayer materials can be greatly improved by constructing two-dimensional van der Waals heterostructures. In this work, the electronic properties and photocatalytic mechanism of the MoTe₂/BAs heterostructure with a stable structure are explored via the density functional theory. According to our results, the heterostructure, with a direct band gap value of 0.70 eV, has an intrinsic type-II band alignment that provides indispensable conditions for photocatalytic applications. The built-in electric field formed at the interface accelerates the reorganization of photogenerated holes in MoTe₂ and photogenerated electrons in BAs, which results in the photogenerated electrons and holes in the heterostructure accumulate in CB of MoTe₂ and VB of BAs, respectively. The spatial separation of photoexcited electrons and holes prolongs the lifespan of carriers and enhances the photocatalytic efficiency of the MoTe₂/BAs heterostructure. Besides, these results demonstrate that the heterostructure possesses higher carrier mobility and a higher light absorption coefficient than two monolayers. The MoTe₂/BAs heterostructure also has a remarkable solar-to-hydrogen efficiency. These distinguishing features confirm the truth that the MoTe₂/BAs heterostructure has promising prospects in the sphere of photocatalysis for water splitting.

通过构建二维范德华异质结构，可以大大提高单层材料的光催化效率。本文通过密度泛函理论研究了具有稳定结构的MoTe ₂ / BAs异质结构的电子性质和光催化机理。根据我们的结果，异质结构的直接带隙值为0.70 eV，具有固有的II型能带排列，这为光催化应用提供了必不可少的条件。在界面处形成的内置电场加速了MoTe ₂中光生空穴和BA中光生电子的重组，这导致异质结构中的光生电子和空穴积累在MoTe _2的CB中和BA的VB。光激发电子和空穴的空间分隔延长了载流子的寿命，并增强了MoTe ₂ / BAs异质结构的光催化效率。此外，这些结果表明，异质结构比两个单层具有更高的载流子迁移率和更高的光吸收系数。MoTe ₂ / BAs异质结构还具有显着的太阳能转化效率。这些区别特征证实了MoTe ₂ / BAs异质结构在光解水光催化领域具有广阔前景的事实。