Tailoring the morphology and microstructure of catalyst is of great importance for improving photocatalytic activity. In this work, intercalating Ni2+ as a chemical scissor to fabricate 0D/2D Ni2P quantum dots/red phosphorus nanosheets photocatalyst via a facile and mild in-situ hydrothermal method was reported. Amongst the catalysts examined 0.1Ni(2)P/red P exhibited extremely high H-2 evolution (265.43 mu mol.g(-1).h(-1)) under visible-light irradiation (lambda >= 420 nm), which is 38.58 and 3.61 times higher than pure red P and 1 wt% Pt/red P, respectively. The characterization of the 0.1Ni(2)P/red P photocatalyst showed that Ni2P exists in the form of quantum dots and red phosphorus presents multi-layered characteristics. The possible formation mechanism of Ni2P QDs and red phosphorus nanosheets was proposed and the reasons for 0.1Ni(2)P/red P with such a high rate of H-2 evolution were systematically investigated.