Pyrite (FeS2)‐decorated 1D TiO2 nanotubes in a bilayer as a sustainable photoanode for photoelectrochemical water splitting activity

Abstract

AbstractHerein, FeS2@TiO2 nanotubes photocatalyst was prepared by electrochemical anodization method followed by successive ionic layer adsorption and reaction method, and then finally annealed in a tube furnace for homogenous crystallization. The surface morphology, elemental composition, optical properties, and crystalline structure of the prepared FeS2@TiO2 nanocomposite were found out by performing scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffraction, UV–Vis diffuse reflectance spectroscopy, and fluorescence spectroscopy, respectively, while bonds vibrations and various functional groups' presence were analyzed using Raman and Fourier transform infrared spectroscopy. A higher photocurrent density of 1.59 mA/cm2 at 0.3 V versus reference electrode of Ag/AgCl (1.23 V versus reversible hydrogen electrode) using 100 mW/cm2 intensive light source was shown by 15‐FeS2@TiO2 nanotubes (uniformly loaded photoanode) while donor density (ND) of 3.68 × 10−13 cm−3 as compared to pure TiO2 NTs (0.09 mA/cm2), 05‐FeS2@TiO2 NTs (0.19 mA/cm2), 10‐FeS2@TiO2 NTs (0.53 mA/cm2) and 20‐FeS2@TiO2 NTs (0.61 mA/cm2), respectively. The exceptional photoelectrochemical activity results were attributed to the homogenous integration of FeS2 that not only increase the charge separation but also, intensively interacted with the substrate (TiO2 nanotubes), which results in an excellent photoelectrochemical activity.