Constructing Dual Cocatalysts of Ni 2 P-NiS-Decorated TiO 2 for Boosting Photocatalytic H 2 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 2 . However, an investigation of the synergistic effect of dual cocatalysts is beneficial for further promoting photocatalytic H 2 production activity. In this work, dual cocatalyst Ni 2 P-NiS-modified TiO 2 nanosheets were fabricated through a solvent evaporation method. The investigation indicates that Ni 2 P-NiS can widen the light absorption range and reduce the contact angle between TiO 2 and water from 26.71 to 8.27°, which facilitates the adsorption of water molecules. Besides, the introduction of Ni 2 P-NiS can decrease the overpotential of H 2 evolution and induce more electrochemically active surface area. The photocatalytic tests show that the H 2 production rate of 15% Ni 2 P-NiS/TiO 2 can reach up to 4891.6 μmol·g -1 ·h -1 , which is 30.2, 4.4, and 1.3 times than pure TiO 2 (161.8 μmol·g -1 ·h -1 ), 15% Ni 2 P/TiO 2 (1112.1 μmol·g -1 ·h -1 ), and 15% NiS/TiO 2 (3678.1 μmol·g -1 ·h -1 ), respectively. The enhancement mechanism of photocatalytic H 2 production is attributed to the Schottky barrier effect between Ni 2 P-NiS nanoparticles and TiO 2 nanosheets, which can enormously promote the interface charge separation and transfer, and enhance the kinetics of H 2 production. This work provides a potential strategy for enhancement H 2 production using appropriate dual cocatalyst-decorated semiconductor materials.