Photocatalytic application of a type-II GaAlSe ₂ /HfSSe van der Waals heterostructure

To address the recent environmental challenge, photocatalytic water splitting offers significant potential, as it only utilizes solar energy to generate hydrogen. From this perspective, in this work, we have studied the optoelectronic and photocatalytic behavior of type-II van der Waals heterostructure (vdwHS) GaAlSe 2 /HfSSe by using density functional theory (DFT). A type-II GaAlSe 2 /HfSSe vdwHS is a semiconductor with an optimal band gap of 1.40[Formula: see text]eV. The optical behavior highlights that the vdwHS GaAlSe 2 /HfSSe possesses significant absorption in the visible region. The band alignment of the GaAlSe 2 /HfSSe vdwHS is favorable for Z-scheme charge transfer, which will facilitate the redox reactions for water decompositions. A type-II GaAlSe 2 /HfSSe vdwHS is a potential candidate for photocatalytic application in the pH range 7–9.