Nickel depositing in TiO2 nanotube photoanode with promoted photoelectrochemical response

The focus of this study was to improve the photoelectrochemical properties of Ni@TiO2 NT nanocomposites by modifying the synthesis conditions, specifically the deposition voltages of nickel nanoparticles. Ni@TiO2 NT nanocomposites on titanium foil (Ti) were compared to the TiO2 NT/Ti photoelectrode in terms of their photoelectrochemical characteristic. Ni@TiO2 NT nanocomposites with various sizes of Ni nanoparticles were successfully prepared using a low cost and eco-friendlily approach (electrochemical deposition process). The effect of deposition voltages on the deposition characteristics of nickel nanoparticles is explored. An X-ray diffractometer was used to ascertain the phase structure of the nanocomposites. Whilst the field emission scanning electron microscope (FESEM) coupled with the energy dispersive x-ray spectrometer (EDX) was employed to examine the surface morphology and the elements that make up the photoelectrode. Moreover, UV-Visible Diffusion Reflectance Spectroscopy was used to determine the absorption spectrum as well as quantify the energy gaps for the prepared photoelectrodes. The bare TiO2 nanotube (TiO2 NT) and Ni@ TiO2 NT nanocomposites were evaluated for their photoelectrochemical properties using the linear sweep voltammetry technique. The findings confirmed that the size of nickel nanoparticles deposited on titania nanotubes has a direct effect on the photoelectrochemical properties of the prepared photoelectrodes. The Ni@TiO2 NT photoelectrode prepared at 4 V possessed a higher photocurrent density (5.06 mA cm(-2)) that was approximately 169 times greater than that of the bare TiO2. Therefore, the Ni@TiO2 NT nanocomposite can be applied as a photoanode in photoelectrochemical implementations based on the results obtained. [Graphical abstract].