Preparation of Cu2O/TiO2 nanotube arrays and their photoelectrochemical properties as hydrogen-evolving photoanode

Cu2O is an environment-friendly p-type semiconductor with narrow band gap (2.0~2.2eV), which has become a popular sensitizer of TiO2. The present work is focused on the preparation of Cu2O/TiO2 nanotube arrays heterostructures via electrochemical deposition. TiO2 nanotube arrays were prepared by anodic oxidation method and calcined at 450°C, then Cu2O were deposited on TiO2 nanotube arrays in a three-electrode system with surfactants PVP in electrolyte at different deposition potentials (-0.2V and-0.3V) for deposition time 5min. The results show that Cu2O nanoparticles deposit on TiO2 nanotube successfully. The obtained Cu2O nanoparticles were quite different in size at deposition potential -0.2V and -0.3V. The resulting Cu2O/TiO2 nanotube arrays have the significant photoresponse in visible light region. Under irradiation of solar simulator (AM1.5, 100mW/cm2), the photocurrent density of the Cu2O/TiO2 nanotube arrays when Cu2O was deposited at a voltage of -0.3V is more than that of pure TiO2 nanotube arrays.