Impedence Characterization of the Donor Materials Effect on Photoelectrocatalytic Hydrogen Production by Water Splitting Using TiO<sub>2</sub> Nanotube Arrays Photoanode

Abstract

Anatase TiO2nanotube arrays with about 50nm pore diameter were prepared by anodic oxidation. The effect of the donor materials (sodium hydroxide, methanol and ethylene glycol) on electrochemistry impedance spectroscopy (EIS) and the photocurrent responses of TiO2nanotube arrays photoanode in the photoelectrochemical cell for splitting water hydrogen production were investigated. The results indicate that all the donor materials enhance the photocurrent responses and reduce the internal reaction resistances of the TiO2nanotube arrays photoanode. The effect of adding organic donor compounds in the anolyte on charge transfer and photocurrent is superior to the inorganic donor compounds and in turn reduces from the ethylene glycol, methanol to sodium hydroxide. Additionally, it should be highlighted that +0.3V vs. open circuit potential of applied potential on the electrode promotes a suitable charge transfer at semiconductor/electrolyte interface. The flat band potentials of TiO2nanotube arrays photoanode move to negative direction with donor materials adding in the anolyte which indicates beneficial photoelectrocatalytic hydrogen production by water splitting.