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

Abstract

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 photocatalysts for efficient photoelectrochemical water splitting.