Preparation Of TiO₂ Film And The Photoelectrochemical Properties Of The TiO₂/Ni(OH)₂ Composite Electrode

Based on the previous works,an improved method to prepare photo-charging TiO₂/Ni(OH)₂ composite electrode was developed.Using Ti foil as the substrate,TiO₂ with rutile structure was formed via anodization technology.Without a high-temperature heat treatment,the experiment conditions were moderate and easy handling.For the as-prepared TiO₂/Ni(OH)₂ electrode,TiO₂ and Ni(OH)₂ combined with the close help of electronic conduction.In addition,the surface microstructure, photoelectrochemical properties and photocatalytic activity of TiO₂,TiO₂/Ni(OH)₂ electrodes prepared at different conditions were evaluated.At first,TiO₂ electrodes were prepared by anodization technology at different current density.Then Ni(OH)₂ was deposited on the surface of TiO₂ to form a TiO₂/Ni(OH)₂ composite electrode.TiO₂ and TiO₂/Ni(OH)₂ composite electrode were characterized by field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD) and UV-vis absorption spectra.Cyclic Voltammograms(CVs) tests in dark and lighting conditions proved that the prepared photocatalyst had a high sensitivity to the light.The comparative experiments revealed that the maximum absorption wavelength shifted to red edge,the photocurrent and photovoltage increased with the increase of anodic current value.However,when the anodic oxidation current increased more than 0.15 A,the photocatalytic efficiency declined. In addition,when the TiO₂ had the higher photocatalytic efficiency,the corresponding TiO₂/Ni(OH)₂ composite electrode showed the better performance of light energy storage and photochromism.Secondly,TiO₂ nanotube arrays were prepared by using constant voltage anodic oxidation at 20 V.SEM images showed that the diameter of the as-prepared TiO₂ ranged from 100 to 200 nm.Ni(OH)₂ could be deposited into TiO₂ nanotubes by electrochemical method to form a TiO₂/Ni(OH)₂ composite electrode.The composite electrode showed the obvious photochromic behaviour and its darkness degree increased with the exposure time and light intensity.The comparative CVs tests carried out in dark and under irradiation confirmed that the composite electrode had high sensitivity to light irradiation.