Few-layered CuInP2S6 nanosheet with sulfur vacancy boosting photocatalytic hydrogen evolution

Photochemical water splitting offers an economic and sustainable approach for solar energy conversion into hydrogen fuel to mitigate the problem of greenhouse gas emissions. To this end, exploring novel semiconductor-photocatalyst, which has efficient light absorption and thermodynamically favorable band alignment for water splitting, is crucial. Here, we rationally develop a new photocatalyst of CuInP2S6 nanosheets to generate hydrogen gas under light illumination. The CuInP2S6 nanosheet (with the thickness of around 4-7 nm) photocatalyst exhibit a high hydrogen production rate of 804 μmol g−1 h−1, eight times higher than that of the microsheet counterpart, due to the introduced abundant sulfur vacancies. The experimental characterizations and theoretical calculations verify the prolonged carrier lifetime and optimize band alignment in ultrathin CuInP2S6 nanosheets to boost photocatalytic hydrogen evolution. This work opens a new avenue for photocatalysis via using novel layered binary metal phosphorous trichalcogenides.