Constructing Dual Cocatalysts of NiP-NiS-Decorated TiO for Boosting Photocatalytic H Evolution.

The loading of cocatalysts is an effective approach to optimize the separation of carriers during photocatalytic processes. Among them, cocatalysts often work independently during the photocatalytic production of H. However, an investigation of the synergistic effect of dual cocatalysts is beneficial for further promoting photocatalytic H production activity. In this work, dual cocatalyst NiP-NiS-modified TiO nanosheets were fabricated through a solvent evaporation method. The investigation indicates that NiP-NiS can widen the light absorption range and reduce the contact angle between TiO and water from 26.71 to 8.27°, which facilitates the adsorption of water molecules. Besides, the introduction of NiP-NiS can decrease the overpotential of H evolution and induce more electrochemically active surface area. The photocatalytic tests show that the H production rate of 15% NiP-NiS/TiO can reach up to 4891.6 μmol·g·h, which is 30.2, 4.4, and 1.3 times than pure TiO (161.8 μmol·g·h), 15% NiP/TiO (1112.1 μmol·g·h), and 15% NiS/TiO (3678.1 μmol·g·h), respectively. The enhancement mechanism of photocatalytic H production is attributed to the Schottky barrier effect between NiP-NiS nanoparticles and TiO nanosheets, which can enormously promote the interface charge separation and transfer, and enhance the kinetics of H production. This work provides a potential strategy for enhancement H production using appropriate dual cocatalyst-decorated semiconductor materials.