The PtSe2/GaN van der Waals heterostructure photocatalyst with type II alignment: A first-principles study

Abstract The research on hydrogen evolution through photocatalytic water splitting has received considerable attention owing to its environmental friendliness. Calculations reveal that PtSe2/GaN heterostructures have excellent thermodynamic and thermal stability. The PtSe2/GaN heterostructure owns the type-II alignment feature, and the photoinduced electrons and holes are distribute on different monolayers. The heterostructure shows exceedingly high carrier mobility with anisotropic feature. The electron mobility along the zigzag direction even reaches up to 23.98 × 103 cm2 V−1 s−1, and it is 133 times as larger as the hole mobility along the armchair direction, thus benefiting the spatial separation of photogenerated electrons and holes. The composite photocatalyst possesses excellent visible light absorption coefficient (∼3.05 × 105 cm-1), which is 2.58 times that of the PtSe2 monolayer. Our research provides a promising candidate for the hydrogen evolution catalyst.