Visible-light-driven ZnIn2S4/CdIn2S4 composite photocatalyst with enhanced performance for photocatalytic H2 evolution

ZnIn2S4/CdIn2S4 composite photocatalysts (x = 0–1) were successfully synthesized via a hydrothermal route. Compositions of ZnIn2S4/CdIn2S4 composite photocatalysts were optimized according to the photocatalytic H2 evolution rate. XRD patterns indicate the as-prepared samples are mixtures of hexagonal and cubic structures. FESEM and TEM images show that the as-prepared samples are composed of flower-like microspheres with wide distribution of diameter. There is obviously distinguishing distribution of Zn, Cd elements among the composite architectures. UV–vis absorption spectra of different compositions exhibit that absorption edges of ZnIn2S4/CdIn2S4 composites slightly move towards longer wavelengths with the increment of CdIn2S4 component. A typical time course of photocatalytic H2 evolution from an aqueous Na2SO3 and Na2S solution over unloaded and PdS-loaded ZnIn2S4/CdIn2S4 composite photocatalyst is carried out. The initial activity for H2 evolution over 0.75 wt% PdS-loaded sample is up to 780 μmol h−1. And the activity of unloaded sample also reaches 490 μmol h−1 with consistent stability.