Direct Z-scheme AlAs/InS heterojunction: a promising photocatalyst for water splitting

The photocatalytic hydrogen production through water splitting is an environmentally friendly method for hydrogen production. By employing the first-principles calculations of density functional theory, the geometric structure and photoelectric characteristics of the AlAs/InS heterostructure were investigated. The analysis reveals that this heterostructure is classified as a type-II heterostructure and possesses the band gap of 1.572 eV, facilitating the generation of photoinduced electron-hole pairs. The built-in electric field from the AlAs side to the InS side endows the AlAs/InS heterostructure with a Z-scheme transfer mechanism. Under the pH conditions of 0–7, the AlAs/InS heterostructure is capable of promoting the redox reactions, thereby achieving water splitting. Furthermore, the AlAs/InS heterostructure exhibits beneficial absorption properties within the visible spectrum. Additionally, the absorption coefficient of the heterostructure can be moderately enhanced and modulated by the application of external stress. These findings suggest that the AlAs/InS heterojunction, as a promising Z-scheme photocatalyst, can be utilized for efficient hydrogen production through water splitting.