Insight into the role of nickel carbide nanoparticles in improving photocatalytic H2 generation over ZnIn2S4 under visible light

Zinc indium sulfide (ZnIn₂S₄) is a Cd-free semiconductor with great potential in various photocatalytic applications. However, its rapid photogenerated charge combination poses some challenges. Constructing ZnIn₂S₄-based heterojunction photocatalysts to address this has proven an effective solution. In this study, we loaded uniform Ni₃C nanoparticles as cocatalysts on layered ZnIn₂S₄ nanostructures to promote photocatalytic H₂ production activity. The optimal 3 % Ni₃C/ZnIn₂S₄ exhibited the highest H₂ generation rate of 393 μmol·g⁻¹·h⁻¹, 4.5 times greater than pure ZnIn₂S₄. The enhanced photocatalytic performance was ascribed to the incorporation of metallic Ni₃C, which provides more catalytically active sites and establishes electron transfer channels at the interfaces, facilitating the photogenerated carrier separation and H₂ production. The photocatalytic mechanism of Ni₃C/ZnIn₂S₄ was proposed through experimental measurements and DFT calculations. This study offers a way to develop efficient ZnIn₂S₄-based visible-light-driven photocatalysts.