Localized NiS2 Quantum Dots on g‐C3N4 Nanosheets for Efficient Photocatalytic Hydrogen Production from Water.

Developing high‐efficiency yet low‐cost photocatalyst for solar hydrogen production by avoiding the use of noble metals has received adequate interest but remains a great challenge to date. This work reports a seed‐mediated hydrothermal approach for the synthesis of NiS2 quantum dots (QDs) anchored two‐dimensional graphitic carbon nitride (g‐C3N4) nanosheets. This hybrid shows superior performance toward photocatalytic H2 evolution from water. The highest H2 evolution rate reaches 4.841 μmol h−1, with an apparent quantum efficiency of 2 % at 425 nm, which is even much higher than that of Pt‐modified g‐C3N4 photocatalyst (2.865 μmol h−1). Moreover, the composite presents good stability without notable activity decay after several cycled tests. It is found that NiS2 QDs are essential for this improvement. These small nanoclusters not only benefit rapid and vectorial diffusion of photogenerated electrons from g‐C3N4 to NiS2, but also promote H2 evolution by decreasing the thermodynamic overpotential for proton reduction. This work thus marks an important step toward designing good‐performance and low‐cost photocatalytic materials for solar H2 conversion. Quantum on the dot: NiS2 quantum dot successfully anchored on the surface of g‐C3N4 promotes both vectorial charge diffusion and rapid proton reduction during photocatalytic water splitting. [ABSTRACT FROM AUTHOR]