Noble metal-free ternary MoS_2/Zn_(0.5)Cd_(0.5)S/g-C_3N_4 heterojunction composite for highly efficient photocatalytic H_2 production

摘要

Novel ternary MoS2/Zn0.5Cd0.5S/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 H2evolution activity, and the maximum H2evolution rate for MoS2(5%)/Zn0.5Cd0.5S/g-C3N4(30%) is 4914 μmol g−1 h−1in Na2S-Na2SO3solutions 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/Zn0.5Cd0.5S/g-C3N4exhibits excellent photostability due to the transfer of photo-generated holes from Zn0.5Cd0.5S to g-C3N4.