3D hierarchical WO3 grown on TiO2 nanotube arrays and their photoelectrochemical performance for water splitting

WO3 with 3D hierarchical structure was successfully grown into the TiO2 nanotube arrays (TiO2 NTs) on Ti substrate by two-steps procedure. First, TiO2 NTs were fabricated through anodization of titanium, and then WO3 nanoparticles were deposited into the TiO2 NTs and the WO3 with 3D hierarchical structures were deposited on the top surface of TiO2 NTs through hydrothermal method. The WO3/TiO2 composite photoelectrode showed better photoelectric response in visible light compared with the pristine TiO2 and WO3 electrodes. A higher photocurrent density was achieved by optimizing the experimental conditions including solution concentration, hydrothermal time and reaction temperature in details. The improvement of photoelectrochemical (PEC) response for WO3/TiO2 composite photoelectrode also indicated an important synergy between visible light absorption and 3D hierarchical structure inherent to WO3 and the new formed semiconductor composite structures fabricated by hydrothermal treatment, which offers a significant improvement in the separation and transmission of photo generated electrons. (C) 2016 Elsevier B.V. All rights reserved.