Hierarchical ZnIn2S4: A promising cocatalyst to boost visible-light-driven photocatalytic hydrogen evolution of In(OH)3

Efficient separation of electrons and holes, associated with the reduction and oxidation, is of great importance in a photocatalytic reaction. 3D hierarchical core-shell-like ZnIn2S4@In(OH)3 microspheres have been fabricated by a facile hydrothermal method via controlling the sulfur source. The marigold-like spherical ZnIn2S4 induced the in situ growth of cubic In(OH)3 nanosheets as the outer shell, which efficiently transferred the photogenerated electrons and achieved efficient charge separation efficiency for highly photocatalytic H2 production. Moreover, the intimate interfacial contact between ZnIn2S4 core and In(OH)3 shell offered rectified charge transfer directions, which further boosted the charge separation. In consequence, the photocatalytic H2 evolution under visible light irradiation was achieved on wide-gap In(OH)3 owing to ZnIn2S4 as a cocatalyst, and a prominent photocatalytic H2 production of 2088 μmol g−1 was obtained on core-shell-like ZnIn2S4@In(OH)3 structure with an apparent quantum efficiency of 1.45% (400 nm), which was nearly 2-folds higher of H2 production rate than the pristine ZnIn2S4. This work provides a prototype material for high efficiency of hydrogen evolution, and gives a new insight for the development of efficient heterojunction photocatalysts.