Noble metal-free ternary MoS2/Zn0.5Cd0.5S/g-C3N4 heterojunction composite for highly efficient photocatalytic H2 production

Novel ternary MoS₂/Zn_0.5Cd_0.5S/graphitic carbon nitride (g-C₃N₄) heterojunction photocatalysts were successfully synthesized for photocatalytic hydrogen production under visible-light illumination (λ ≥400 nm). Compared with the pure samples and binary composites, the heterostructure photocatalysts displayed improved H₂ evolution activity, and the maximum H₂ evolution rate for MoS₂(5%)/Zn_0.5Cd_0.5S/g-C₃N₄(30%) is 4914 μmol g⁻¹ h⁻¹ in Na₂S-Na₂SO₃ solutions with an apparent quantum efficiency of 34.2% at 420 nm. Based on the photoluminescence and electrochemical results, the improved photoactivity can be attributed not only to the formation of heterojunction, resulting in the efficient separation of charge carriers, but also to the introduction of MoS₂, which leads to and accelerated surface reaction. Meanwhile, as-synthesized MoS₂/Zn_0.5Cd_0.5S/g-C₃N₄ exhibits excellent photostability due to the transfer of photo-generated holes from Zn_0.5Cd_0.5S to g-C₃N₄.