Synthesis of Cd1-xZnxS/K4Nb6O17 Composite and its Photocatalytic Activity for Hydrogen Production

Abstract

Cd1-xZnxS-sensitized K4Nb6O17 composite photocatalysts (designated Cd1-xZnxS/K4Nb6O17) were prepared via a simple deposition-precipitation method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), N2 sorption, ultraviolet-visible light diffuse reflectance spectroscopy (UV-Vis DRS), photoluminescence measurements (PL), and X-ray photoelectron spectroscopy (XPS). The Cd0.8Zn0.2S particles were scattered on the surface of K4Nb6O17, and had a relatively uniform size distribution around 50 nm. The absorption edge of K4Nb6O17 was shifted to the visible light region and the recombination of photo-generated electrons and holes suppressed after Cd0.8Zn0.2S loading. The Cd0.8Zn0.2S(25 wt %)/K4Nb6O17 composite possessed the highest photocatalytic activity for hydrogen production under visible light irradiation, evolving 8.278 mmol/g in 3 h. Recyclability tests were performed, and the composite photocatalysts were found to be fairly stable. The mechanism of charge separation between the photogenerated electrons and holes at the Cd0.8Zn0.2S/K4Nb6O17 composite was discussed.