PtSe₂/TiO₂ nanotubes heterostructure for enhanced photoelectrochemical water splitting

Group 10 transition metal dichalcogenide PtSe₂ has drawn considerable attention toward the search for an efficient visible light photocatalyst due to its strong light–matter interaction nature. Here we report PtSe₂/TiO₂ heterostructure for solar energy conversion through photoelectrochemical (PEC) water splitting. The PtSe₂/TiO₂ heterostructure was prepared by sputtered Pt film followed by the chemical vapor deposition method. Raman spectroscopy and X-ray diffraction analysis confirmed the growth of hexagonal phase PtSe₂ and anatase TiO₂ corresponding to their distinguished peak characteristics. The field-emission scanning electron microscopy and transmission electron microscopy studies reveal that TiO₂ nanotubes were decorated with PtSe₂ nanoflakes forming PtSe₂/TiO₂ heterostructure. The chemical composition of the prepared samples was studied by using the X-ray photoelectron spectroscopy and indicated the sole presence of PtSe₂ and TiO₂ compounds. The PEC measurements were taken in 0.5 M Na₂SO₄ electrolyte solution under simulated sunlight (AM = 1.5 G). The maximum photocurrent density of ~ 234.7 µA/cm² at 1.4 V versus RHE was recorded for PtSe₂/TiO₂ heterostructure, which is 1.7 times higher than that of Pt/TiO₂. The improved PEC performance of PtSe₂/TiO₂ as a result of efficient solar absorption over a wider spectrum and effective charge separation produced by type-II band alignment between PtSe₂ and TiO₂.