Direct Z-scheme GeH/InSe heterostructure with high solar-to-hydrogen efficiency for photocatalytic water splitting

The stability, electronic structures and photocatalytic applications of GeH/InSe heterostructure are studied through first-principles calculations. The GeH/InSe heterostructure can be used as a direct Z-scheme photocatalyst for overall water splitting due to the influence of the built-in electric field and the interface band bending. The heterostructure exhibits a lower exciton binding energy than their individual constituents, indicating the effective separation of electron-hole pairs. Electron mobilities along transport directions are two orders of magnitude greater than hole mobilities, which further prompts the carriers separation rate. The heterostructure's solar-to-hydrogen efficiency is 24.72 % at pH = 0, indicating great application prospects in photocatalysis.