Gemstone nanoflower-shaped ZnIn2S4/CuS heterojunction with ultralong lifetime of photoinduced carriers for photocatalytic hydrogen evolution

Efficient photoinduced charge separation achieving an extremely long lifetime for improving the photocatalytic activity in hydrogen evolution reaction (HER) is essential to obtain high performance. Here, we crafted and designed the gemstone nanoflower-shaped ZnIn2S4/CuS (ZIS/CuS) heterostructure by the n-type ZIS nanoparticles grown on p-type CuS nanoflowers. The ZIS/CuS exhibited the photocatalytic HER rate of 1659 μmol∙g−1∙h−1 under visible light irradiation which was higher than that of ZIS nanoflower and CuS gemstone-shape. It has been attributed to the formation of type-II-scheme p−n heterojunction structure with a strong interfacial build-in electric field and the efficient photoinduced charge separation up to an ultralong lifetime of 4.89 ms. It was directly demonstrated by the in-situ X-ray photoelectron spectroscopy and femtosecond-million second transient absorption spectra (fs-ms TAS). This study provides a new strategy for constructing type-II p−n heterostructures with high photocatalytic activity and strong stability for photocatalytic HER.