Electrochemical and photoelectrochemical characteristics of TiNbO5 nanosheet electrode

Abstract Exfoliated TiNbO 5 nanosheets were obtained by delaminating a layered compound KTiNbO 5 . Employing a layer-by-layer electrostatic deposition technology, the exfoliated nanosheets were deposited into a multilayer composite film with polyethylenimine as the linker, confirmed by UV–vis absorption spectra and X-ray diffraction. The polymer-free TiNbO 5 nanosheet multilayer film was achieved through the subsequent ultraviolet light exposure. The cyclic voltammogram of the resulting TiNbO 5 nanosheet multilayer film electrode exhibited a reversible reduction–oxidation process of Ti 3+ /Ti 4+ , accompanying with the insertion/deinsertion of Li + ions into/from the nanosheet galleries. The bandgap energy and flatband potential of TiNbO 5 nanosheet were observed to be 3.47 eV and −1.01 V vs. Ag/AgCl, respectively. The investigation on the photoelectrocatalytic degradation of Rhodamine B with the TiNbO 5 nanosheet electrodes revealed that both the oxygen anionic radicals and the dye cationic radical are essential for the mineralization of the dye under visible light-driven photocatalytic conditions, and that the electron separation under an anode bias can suppress the rapid recombination of the photogenerated charge carriers under ultraviolet light irradiation. It is the first time to investigate the mechanism of photoelectrocatalysis for TiNbO 5 nanosheet electrode.