Fabrication of TiO2-NTs and TiO2-NTs covered honeycomb lattice and investigation of carrier densities in I−/I3− electrolyte by electrochemical impedance spectroscopy

Abstract

The TiO2 nanotubes (NTs) were produced by one-step (1S) and two-step (2S) anodization technique. Effects of various anodization potential and times on the growth of TiO2-NTs were investigated by using Field Emission-Scanning Electron Microscopy (FE-SEM). The crystal structure of the electrodes was determined with X-ray powder diffractometry (XRD). The most suitable potential and time for TiO2-NTs obtained by both of anodization methods were found to be 21V and 4h. XRD results indicated that 2S anodization technique provided better crystallinity. The electrochemical behaviors of the electrodes in acetonitrile electrolyte contained I−/I3− were examined by utilizing electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) techniques. Electrochemical results showed that 2S anodization technique increases the carrier densities (ND) value of TiO2-NTs, and flat band potential is shifted by 50mV to more negative values.