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

Abstract

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 photocatalysts, which have 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 a thickness of around 4–7 nm) photocatalyst exhibits 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. Experimental characterization and theoretical calculations verify that the prolonged carrier lifetime and optimized band alignment in ultrathin CuInP₂S₆ nanosheets boost photocatalytic hydrogen evolution. This work opens a new avenue for photocatalysis via using novel layered binary metal phosphorous trichalcogenides.