Synergistic Effect of Photonic Crystals and Oxygen Vacancies on Photoelectrochemical Water Splitting of TiO2 Nanotube

TiO 2 nanotube photonic crystals with a mass of oxygen vacancies ( V O -TiO 2 NTPCs) are prepared through a simple electrochemical reduction. The novel V O -TiO 2 NTPCs produce a photocurrent density of 1.4 mA/cm 2 at 0.22 V versus Ag/AgCl with Faradic efficiency of 100%, which is 1.75 times that of pristine TiO 2 NTPCs. The improved performance is contributed to the fact that the oxygen vacancies created by electrochemical reduction, which not only promote efficient utilization of the visible light absorption, but also increase electrical conductivity. This work will contribute to the design and fabrication of the TiO 2 nanotube-based photoelectric devices.