TiO₂ nanotube arrays photoelectrodes were prepared by anode oxidation on pure Ti sheet. The donor material glycol (C₂H₆O₂) added in the anode electrolyte significantly reduced the charge transfer impedance of TiO₂ nanotubes to promote the photocatalytic water splitting for hydrogen production. TiO₂ nanotube arrays electrodes were modified by cerium and oxidative cerium with electrochemical deposition and anodic oxidation. The flat band potential moves to the negative potential direction after modification. Electrochemical impedance spectrum (EIS) measurement was used to investigate the electron transfer characteristic in photoelectrodes and the interface characteristic in the photoelectrochemical cell (PEC) for hydrogen production. Arcs of EIS and corresponding electrode processes were discussed. Dynamic parameters of the electrodes were calculated by reasonable electrical equivalent circuit fitting. The results indicate that TiO₂ nanotube arrays electrode modified by cerium and oxidative cerium could largely decrease the electron transfer resistance which contributes to hydrogen production. The mechanism of the cerium and oxidative cerium acting on TiO₂ nanotube arrays to promote charge transfer is discussed.

Key words: TiO₂ nanotube, cerium, oxidative cerium, EIS, water splitting, hydrogen