Coupling Ni-substituted polyoxometalate catalysts with water-soluble CdSe quantum dots for ultraefficient photogeneration of hydrogen under visible light

The development of robust and efficient hydrogen-evolving system remains a substantial but promising challenge to convert solar energy into clean fuel. Herein, we report the construction of water-compatible, robust, and ultraefficient hydrogen-evolving system by coupling water-soluble CdSe light-absorbers with Ni-substituted polyoxometalate (Ni-POM) catalysts and AA electron donor. Such facile catalytic system exhibits superior and robust hydrogen production activity to date even among known semiconductor/POM hybrids-based hydrogen production systems. Multiple stability experiments confirm the molecular stability of Ni-POM catalysts under turnover conditions. Various experimental and spectroscopic analyses reveal that the synergistic cooperation between high photostability of CdSe light-absorber, outstanding reversible multi-electron-transferring property of Ni-POM catalyst, and the fast hole-removing ability of AA electron donor account for the exceptional performance of present catalytic system. Our present work provides new research insights into the continued development of effective hydrogen-evolving systems through coupling other QDs-based light-absorbers and earth-abundant transition-metal-substituted POM catalysts. [Display omitted] •The ultraefficient H2-evolving system was constructed by coupling CdSe QDs with Ni-substituted polyoxometalate catalysts.•This work exhibits superior H2 production activity to date among known semiconductor/POM hybrids-based catalytic systems.•Multiple stability experiments confirm the molecular integrity of Ni-POM catalysts under turnover conditions.•Mechanistic studies reveal the synergistic cooperation between CdSe QDs, Ni-POM catalysts, and ascorbate electron donor.