Novel NiS cocatalyst decorating ultrathin 2D TiO2 nanosheets with enhanced photocatalytic hydrogen evolution activity

In this paper, ultrathin 2D TiO 2 nanosheets which modified with ultrafine dispersions of NiS cocatalyst were successfully prepared via a low-cost and in-situ synthesis approach. The physical and chemical properties of the as-obtained NiS/TiO 2 nanosheets samples were investigated by a variety of analytical techniques. Cooperated with the photocatalytic hydrogen evolution tests and surface photovoltage spectroscopy (SPV) experiments, it can be deduced that the NiS is an efficient cocatalyst, which significantly limited the recombination of photogenerated electron-hole pairs in ultrathin 2D TiO 2 nanosheets and consequently improve the hydrogen evolution activity. The influence of different molar ratios of NiS on the photocatalytic activity was explored and the 5 mol% NiS/TiO 2 composite photocatalyst showed the highest photoactivity which the corresponding H 2 -production rate was 313.6   μmol   h −1   g −1 under the UV–vis light irradiation. The optimal H 2 evolution rate is 36 times as much as the value of pure TiO 2 nanosheets. The photocatalytic mechanism of NiS cocatalysts on the enhanced performance of the photocatalytic activity of TiO 2 nanosheets is proposed and confirmed by SPV results.