Constructing direct Z-scheme Mn0.5Cd0.5S/CdWO4 nanocomposite modified by hollow CoSx polyhedrons for highly efficient photocatalytic H2 evolution

Constructing heterojunction photocatalytic systems with highly spatial charge separation, strong photoredox ability and rapid surface reaction still remains an enormous challenge. Herein, hollow CoSx polyhedrons decorated hierarchically direct Z-scheme Mn0.5Cd0.5S/CdWO4 heterojunction photocatalyst is designed and constructed by a simple sonochemical approach and subsequent in situ deposition route. Such a constructed Mn0.5Cd0.5S/CdWO4/CoSx ternary composite exhibits a significantly boosted photoactivity toward H2 generation compared to bare Mn0.5Cd0.5S, binary Mn0.5Cd0.5S/CdWO4, Mn0.5Cd0.5S/CoSx and Mn0.5Cd0.5S/Pt samples with optimized composition ratio. Apart from the efficient charge transfer channels and preserved strong photoredox ability within the direct Z-scheme Mn0.5Cd0.5S/CdWO4 heterojunction, the hollow structure of CoSx polyhedrons could endow abundant surface-active sites, strengthen the light-harvesting capacity through the internal multilight scattering/reflection and decrease the overpotential for H2 evolution, which further contributes to the boosted photoactivity toward hydrogen production. This study demonstrates an alternate methodology for constructing high-performance multi-hierarchical Z-scheme/cocatalyst heterojunction photocatalysts for solar energy conversion.