Functionalized Cd_0.5Zn_0.5S Chalcogenide Nanotwins Enabling Z-Scheme Photocatalytic Water Splitting

Coherent twin boundaries in particulate chalcogenide photocatalysts can induce intrinsic homojunctions, which have been demonstrated to be effective toward solar hydrogen production from water. However, limited success up to date has been achieved on pure water splitting because of the self-oxidation of the chalcogenide photocatalyst. Herein, we report the efficient pure water splitting for simultaneous H2 and H2O2 production under visible light irradiation over a Cd0.5Zn0.5S (CZS) nanotwin photocatalyst. The success relies on the formation of unique phosphorus bridges at the surface of the photocatalyst that couples bulk twin boundaries and surface red phosphorus (RP) for efficient charge separation and restricted photocorrosion via a two-electron Z-scheme mechanism. The optimal photocatalyst exhibited 5.2 times increased H2 evolution rate compared to the pristine CZS and good stability as well. This work opens a door toward chalcogenide photocatalyst design for efficient pure water splitting by coupling twin nanostructures with surface P doping and heterojunction construction.