Enhanced Photocatalytic Hydrogen Evolution by Loading Cd 0.5 Zn 0.5 S QDs onto Ni 2 P Porous Nanosheets.

Ni ₂ P has been decorated on CdS nanowires or nanorods for efficient photocatalytic H ₂ production, whereas the specific surface area remains limited because of the large size. Here, the composites of Cd _0.5 Zn _0.5 S quantum dots (QDs) on thin Ni ₂ P porous nanosheets with high specific surface area were constructed for noble metal-free photocatalytic H ₂ generation. The porous Ni ₂ P nanosheets, which were formed by the interconnection of 15-30 nm-sized Ni ₂ P nanoparticles, allowed the uniform loading of 7 nm-sized Cd _0.5 Zn _0.5 S QDs and the loading density being controllable. By tuning the content of Ni ₂ P, H ₂ generation rates of 43.3 μM h ^- 1 (1 mg photocatalyst) and 700 μM h ^- 1 (100 mg photocatalyst) and a solar to hydrogen efficiency of 1.5% were achieved for the Ni ₂ P-Cd _0.5 Zn _0.5 S composites. The effect of Ni ₂ P content on the light absorption, photoluminescence, and electrochemical property of the composite was systematically studied. Together with the band structure calculation based on density functional theory, the promotion of Ni ₂ P in charge transfer and HER activity together with the shading effect on light absorption were revealed. Such a strategy can be applied to other photocatalysts toward efficient solar hydrogen generation.