Photocatalysis screening for group III-V vdW heterostructures constructed by MX (M = Ga, In and X = P, As) monolayers.

To harvest solar energy for water splitting and produce pollution-free hydrogen and oxygen, high-performance photocatalysts are essential. Here, by combining different two-dimensional (2D) group III-V MX (M = Ga, In and X = P, As) monolayers, we designed 144 van der Waals (vdW) heterostructures to identify efficient photoelectrochemical materials. Using first-principles calculations, we investigated the stabilities, electronic properties, and optical properties of these heterostructures. After a careful screening process, we elected GaP/InP in a BB-II stacking configuration as the most promising candidate. This specific GaP/InP configuration has a type-II band alignment with a gap value of 1.83 eV. The conduction band minimum (CBM) is located at -4.276 eV, and the valence band maximum (VBM) is located at -6.217 eV, fully satisfying the requirements of the catalytic reaction under pH = 0. Additionally, light absorption has been improved through the construction of the vdW heterostructure. These results could help in understanding the properties of the III-V heterostructures and guide the experimental synthesis of these materials for photocatalysis applications.