Electrochemical formation of novel TiO2-ZnO hybrid nanostructures for photoelectrochemical water splitting applications

Abstract

In this study, hybrid ZnO-TiO2 nanostructures have been synthesised by means of a simple electrochemical anodisation of titanium and subsequently ZnO electrodeposition. The influence of Zn(NO3)2 concentration and temperature during the electrodeposition process was evaluated. Different techniques were used to analyse the synthesised nanostructures, notably Field Emission Scanning Electron Microscopy (FE-SEM) with Energy-dispersive X-ray spectroscopy (EDX) and Confocal Microscopy with Raman spectroscopy coupled with an Atomic Force Microscope. Photoelectrochemical water splitting tests were also performed at the hybrid nanostructures. According to the results, the photoelectrochemical response of the specimens increases with the addition of ZnO, besides the hybrid nanostructures obtained at 25 °C and using a Zn(NO3)2 concentration of 1 mM showed photocurrent densities 80% higher than the ones obtained for TiO2 nanotubes. Analysis of Variance of the data confirms the obtained results.