One-dimensional TiO2 nanotube array photoanode for a microfluidic all-vanadium photoelectrochemical cell for solar energy storage
In this work, a highly efficient TiO2 nanotube array photoanode prepared by anodizing treatment of titanium foil is developed for an all-vanadium photoelectrochemical cell with a miniaturized design for solar energy storage. The highly ordered structure and miniaturization design have the intrinsic advantages of not only providing a large active surface area and plentiful pores but also enhancing mass and electron transport. Consequently, the developed photoanode exhibits both good photoresponse and operation stability under irradiation. Besides, the solar energy storage performance of the microfluidic all-vanadium photoelectrochemical cell with the developed TiO2 nanotube array photoanode is evaluated under various light intensities and vanadium ion concentrations. The performances of TiO2 nanotube array photoanodes prepared with different anodizing voltages are also investigated. The obtained results show that an increase in both the light intensity and vanadium ion concentration can improve the performance in terms of photocurrent density and vanadium ion conversion rate. The photoanodes prepared at higher anodizing voltages have larger active surface area and photocatalyst loading, thus leading to the improved performance.