Novel mesoporous TiO2 nanotube arrays were synthesized by an anodization method combined with a chemical etching method for enhancing photoelectrochemical activity. Morphologies, structures and elemental compositions of the mesoporous TiO2 nanotube arrays were characterized with scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Photoelectrochemical properties were measured with cyclic voltammetry and chronoamperometry using an electrochemical workstation equipped with a UV LED light source (365 nm). Higher photoelectrochemical activities of the mesoporous TiO2 nanotube arrays can be achieved, with the highest photocurrent being triple that of un-etched TiO2 nanotube arrays. High electrochemical active surface area, optical absorption ability and charge transfer rate play key roles in enhancing the photoelectrochemical activity of the mesoporous TiO2 nanotube arrays.
