A novel sandwich-type polyoxometalate, [Ni-4(II)(H2O)(2)(TiW9O34)(2)](12-)(Ni4Ti2), has been developed for noble metal-free hydrogen evolution reaction (HER). Employing a simple three-component catalytic system, with triethylamine as sacrificial donor and fluorescein as photosensitizer, Ni4Ti2 exhibits outstanding efficiency in hydrogen evolution upon visible light irradiation. The turnover number (TON) of Ni4Ti2 reaches 2000 in 3 h. Spectral studies reveal that the hydrogen evolution process is mainly a reductive one. (C) 2018 Published by Elsevier Inc.