Hydrothermal preparation and characterization of nanostructured CNTs/ZnFe2O4 composites for solar water splitting application

Multi-walled carbon nanotubes (CNTs)/ZnFe2O4 composites were fabricated hydrothermally via direct growth of ZnFe2O4 nanoparticles on the CNTs surface. The as-obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and UV-visible diffuse reflectance spectra (UV-vis DRS) techniques. The photocatalytic performance was evaluated by water splitting in methanol aqueous solution under high-pressure Hg lamp illumination. The effects of CNTs content in the composites on the solar H-2 generation activity were investigated comparatively. Compared with bare ZnFe2O4, the CNTs/ZnFe2O4 hybrid exhibited enhanced photocatalytic H2 evolution activity. The photoluminescence emission spectra (PL) showed that the fluorescence of CNTs/ZnFe2O4 composites was quenched significantly in comparison with that of pristine ZnFe2O4, indicating that an enhanced charge carrier separation efficiency was achieved. Also, a probable mechanism of CNTs for the enhancement of H-2 evolution performance is proposed and discussed. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.