Photocatalytic hydrogen evolution under visible light irradiation by the polyoxometalate α-[AlSiW11(H2O)O39]5− -Eosin Y system

It is important to construct a stable and efficient dye sensitization system for visible-light photocatalytic hydrogen evolution. Eosin Y (EY)-sensitized α-[AlSiW11(H2O)O39]5− (AlSiW11) (an Al3+ substituted Keggin polyoxometalate (POM)) for the hydrogen evolution under visible light irradiation (λ > 420 nm) has been carried out in the presence of triethanolamine as electron donor and Pt as co-catalyst. EY can coordinate with AlSiW11. The coordination association between AlSiW11 and EY is beneficial to the charge transfer from EY to AlSiW11 and to stability of EY. The system displays efficient and stable photocatalytic hydrogen evolution. The average apparent quantum efficiency and turnover number of EY during 20 h irradiation (λ > 420 nm) are 10.3% and 473, respectively. The highest quantum efficiency amounts to 28.0% under 520 nm monochromatic light irradiation. The present study highlights linking between dye and POM molecule as a way to develop new visible-light stable photocatalyst or system.

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► Eosin Y (EY) as sensitizer and α-[SiAlW11(H2O)O39]5− as sensitized substrate.
► There is a coordination interaction between AlSiW11 and EY.
► The interaction enhances charge transfer from EY to the substrate and stabilizes EY.
► The system exhibits efficient and stable photocatalytic hydrogen evolution.