A novel, noble-metal-free core-shell structure Ni–P@C cocatalyst modified sulfur vacancy-rich ZnIn2S4 2D ultrathin sheets for visible light-driven photocatalytic hydrogen evolution

Abstract Accelerating the carrier transfer and increasing the effective reaction site on the surface of photocatalyst are important measures to improve the hydrogen production of composite photocatalyst. Herein, through simultaneous carbonization and phosphorization strategies, a Ni-based metal-organic frameworks (MOFs) derived method is presented to prepare a promising cost-effective Ni–P@C cocatalyst and couple with S-vacancy ZnIn2S4 (Vs-ZIS) for boosting photocatalytic activity. In this system, abundant S vacancies are induced to the surface of ZnIn2S4 ultrathin sheets (4 nm thickness) to capture photoinduced electrons, thus avoiding the recombination of carriers on the surface of ZnIn2S4. Furthermore, Ni–P is introduced to enhance the transfer of photogenerated electrons and increase the reaction site, and the synthesized Ni–P@C cocatalyst is developed to act as electronic container where the carbon framework with graphitic sp2 hybridized structures enables strong electronic interactions at the interface layer. The Ni–P@C/Vs-ZIS-2 photocatalyst exhibits a robust H2 evolution rate of 11,064 μmol g−1 h−1, higher than Vs-ZIS (1542 μmol g−1 h−1) and ZIS (398 μmol g−1 h−1), and the apparent quantum efficiency of Ni–P@C/Vs-ZIS-2 is 12.4%. This study uncovers the role of surface S-vacancy of the ultrathin two-dimensional catalyst ZnIn2S4 coupling with Ni–P@C cocatalyst in affecting electron transfer and reaction site, opening new opportunities for achieving efficient hydrogen production.