3D hierarchical WO3grown on TiO2nanotube arrays and their photoelectrochemical performance for water splitting

WO3with 3D hierarchical structure was successfully grown into the TiO2nanotube arrays (TiO2NTs) on Ti substrate by two-steps procedure. First, TiO2NTs were fabricated through anodization of titanium, and then WO3nanoparticles were deposited into the TiO2NTs and the WO3with 3D hierarchical structures were deposited on the top surface of TiO2NTs through hydrothermal method. The WO3/TiO2composite photoelectrode showed better photoelectric response in visible light compared with the pristine TiO2and WO3electrodes. 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/TiO2composite photoelectrode also indicated an important synergy between visible light absorption and 3D hierarchical structure inherent to WO3and the new formed semiconductor composite structures fabricated by hydrothermal treatment, which offers a significant improvement in the separation and transmission of photo generated electrons. © 2016 Elsevier B.V.