2D/2D heterointerface engineering of Ni2P/ZnIn2S4 photocatalysts for enhanced photocatalytic H2 evolution

Zinc indium sulfide (ZnIn 2 S 4 ) possesses excellent photosensitivity and a suitable band structure, exhibiting superior photocatalytic activity under visible light. However, rapid recombination of photogenerated carriers and sulfide poisoning inhibit its photocatalytic hydrogen production performance. In this study, Ni 2 P nanosheets as cocatalysts were assembled onto the surface of ZnIn 2 S 4 nanoflowers (Ni 2 P@ZnIn 2 S 4 ) for photocatalytic H 2 production. The 6 wt% Ni 2 P@ZnIn 2 S 4 with the optimal ratio exhibited a significantly enhanced photocatalytic H 2 evolution activity (5.82 mmol g −1 h −1 ), which is twice that of ZnIn 2 S 4 (2.85 mmol g −1 h −1 ) and 1.14 times that of Pt/ZnIn 2 S 4 (5.11 mmol g −1 h −1 ). In addition, the apparent quantum efficiency (AQE) of Ni 2 P@ZnIn 2 S 4 reaches 5.70 % and 1.03 % at 370 and 456 nm. According to the experimental data and DFT calculation, the improvement in the catalytic performance of Ni 2 P@ZnIn 2 S 4 is attributed to the following points: 1) ZnIn 2 S 4 nanoflowers composed of 2D nanosheets can improve light absorption, enhance charge and mass transfer, and increase the specific surface area. 2) 2D Ni 2 P as a co-catalyst could better couple with the 2D sheet unit of ZnIn 2 S 4 , improving charge transport, suppressing photogenerated carrier recombination, and providing Ni active sites for surface redox reactions. These synergistic effects highlight the spatial separation and interfacial transfer of photogenerated carriers between semiconductors and cocatalysts achieved through two-dimensional nanosheet heterostructures, providing an effective solution to the carrier recombination problem.