Constructing Dual Cocatalysts of Ni₂P-NiS-Decorated TiO₂ for Boosting Photocatalytic H₂ 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 H₂. However, an investigation of the synergistic effect of dual cocatalysts is beneficial for further promoting photocatalytic H₂ production activity. In this work, dual cocatalyst Ni₂P-NiS-modified TiO₂ nanosheets were fabricated through a solvent evaporation method. The investigation indicates that Ni₂P-NiS can widen the light absorption range and reduce the contact angle between TiO₂ and water from 26.71 to 8.27°, which facilitates the adsorption of water molecules. Besides, the introduction of Ni₂P-NiS can decrease the overpotential of H₂ evolution and induce more electrochemically active surface area. The photocatalytic tests show that the H₂ production rate of 15% Ni₂P-NiS/TiO₂ can reach up to 4891.6 μmol·g^-1·h^-1, which is 30.2, 4.4, and 1.3 times than pure TiO₂ (161.8 μmol·g^-1·h^-1), 15% Ni₂P/TiO₂ (1112.1 μmol·g^-1·h^-1), and 15% NiS/TiO₂ (3678.1 μmol·g^-1·h^-1), respectively. The enhancement mechanism of photocatalytic H₂ production is attributed to the Schottky barrier effect between Ni₂P-NiS nanoparticles and TiO₂ nanosheets, which can enormously promote the interface charge separation and transfer, and enhance the kinetics of H₂ production. This work provides a potential strategy for enhancement H₂ production using appropriate dual cocatalyst-decorated semiconductor materials.