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

Novel ternary MoS2/Zn0.5Cd0.5S/graphitic carbon nitride (g-C3N4) heterojunction photocatalysts were successfully synthesized for photocatalytic hydrogen production under visible-light illumination (lambda >= 400 nm). Compared with the pure samples and binary composites, the heterostructure photocatalysts displayed improved H-2 evolution activity, and the maximum H-2 evolution rate for MoS2(5%)/Zn0.5Cd0.5S/g-C3N4(30%) is 4914 mu mol 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/Zn0.5Cd0.5S/g-C3N4 exhibits excellent photostability due to the transfer of photo-generated holes from Zn0.5Cd0.5S to g-C3N4.