Facile synthesis of a heterogeneous Li2TiO3/TiO2 nanocomposite with enhanced photoelectrochemical water splitting

A heterogeneous Li2TiO3/TiO2 nanocomposite was successfully prepared from anodized amorphous TiO2 nanotube arrays in CH3COOLi solution by using a facile hydrothermal method. Morphology transformation from nanotubes into diamond-shaped nanoparticles can be attributed to the water-induced dissolution and recrystallization processes of the nanotube arrays in a weak acid salt solution. Scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction results showed that a large amount of Li2TiO3/TiO2 diamond-shaped nanoparticles were formed on the surface of the TiO2 nanotube arrays. UV-vis diffuse reflectance spectra indicated improved visible light absorbance. The enhanced photoelectrochemical water splitting was demonstrated under UV-vis light illumination, and the photocurrent density of the electrode prepared in 0.1 M CH3COOLi was greater than that of other electrodes. The semiconductor characteristics were studied using electrochemical impedance spectroscopy in detail. This work is expected to guide next studies to design and fabricate photo-catalysts for efficient photoelectrochemical water splitting.