Efficient ZnS–ZnO/ZnAl-LDH composite for H2 production by photocatalysis

Abstract

In the present work, the synthesis of ZnS–ZnO composites supported on ZnAl-LDH material with photocatalytic applications is proposed. The ZnS–ZnO/ZnAl-LDH composites showed to be efficient for the photocatalytic H2 production using UV light and methanol as sacrificial agent. The ZnO/ZnAl-LDH precursor material was synthesized by the coprecipitation method, then, it was partially sulfided using different contents of thiourea by the solvothermal method. The most photo-active material showed a H2 production of 1599 μmolh−1g−1 and an apparent quantum yield of 37.9%. These materials were characterized by X-ray diffraction, Rietveld refinement, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, N2 adsorption-desorption isotherms, high-resolution transmission electron microscopy and elementary mapping. The ZnS–ZnO/ZnAl-LDH composites exhibited a H2 evolution higher than the precursor material under the same conditions. The increase on the H2 production was attributed to the formation of ZnS–ZnO heterojunction; and in addition, the ZnAl-LDH material acts as a support promoting the dispersion of the ZnS–ZnO composite on its surface.