INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, vol.44, no.23, pp.11488-11502, 2019 (SCI-Expanded)
In the present study, zinc oxide doped titanium dioxide nanotubes (ZnO/TiO2-NTs) were designed by using electrochemical deposition method. Titanium dioxide nanotubes (TiO2-NTs) were fabricated by anodization method. Nanostructured ZnO was deposited with various deposition times on TiO2-NTs. The morphological, structural, optoelectronic properties of ZnO/TiO2-NTs were examined in detail. The morphological and structural characterization of obtained electrodes was investigated with help of field emission scanning electron microscopy and X-ray diffraction. ZnO nanostructures with three different morphologies were obtained from nanotowers to nanoleafs. XRD results depicted that ZnO nanostructures have the high crystallinity with hexagonal wurtzite structure. The measurements of the contact angle were utilized to determine the wetting behavior of the obtained surface of materials. Electrochemical impedance spectroscopy measurement was used in 1 M KOH to investigate electrocatalytic behavior of the obtained materials towards hydrogen evolution reaction. Flat band potentials, as well as charge carrier densities, were determined by using Mott-Schottky analysis. The charge carrier densities were calculated as 1.06 x 10(19) and 1.66 x 10(20) cm(-3) for TiO2-NTs and 30-ZnO/TiO2-NTs, respectively. The energy consumption and energy efficiency were determined for hydrogen evolution on ZnO/TiO2-NTs electrodes. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.