Electrodeposition of flake-like Cu2O on vertically aligned two-dimensional TiO2 nanosheet array films for enhanced photoelectrochemical properties

A novel Cu2O/TNS composite structure of single crystal TiO2 nanosheet (TNS) arrays decorated with flake like Cu2O were synthesized by a facile hydrothermal reaction followed by the electrodeposition process. The effects of deposition potential on the microstructure, morphology, and optical property of the thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis spectrophotometer. When the deposition potential is higher than -0.4V, peaks corresponding to Cu appear, meanwhile, flake-like Cu2O become agglomerating, and transform into dense Cu2O particles. Additionally, photoelectrochemical experiments indicate that the films deposited at 0.4V show the lowest resistivity and highest exciton separation efficiency. This enhanced photoelectrochemical properties can be explained by synergistic effect of p-type flake-like Cu2O and n-type TiO2 heterojunctions combined with two-dimensional TiO2 nanosheet with exposed highly reactive {001} facets. (C) 2016 Elsevier B.V. All rights reserved.