Pre- and post-oxidation treatment of titanium as a method of improving the response of TiO2-based photoanodes in PECs

Abstract

TiO2-based photoanodes were prepared via thermal oxidation of titanium foils in air at 500–900[Formula: see text]C. Some of them were pre-treated via etching with HCl prior to oxidation, and others post-treated by means of sensitization with Ag2S or CdS. XRD analysis revealed that the formation of rutile is observed even at 500[Formula: see text]C. Etching prior to oxidation removes the Ti passivation layer and facilitates the oxidation process, and lowers the temperature at which the fundamental absorption edge is observed. The highest photocurrent values measured in a photoelectrochemical cell (PEC) were obtained for anodes etched prior to oxidation. Sensitization with CdS or Ag2S increased photocurrent drastically. It was demonstrated that pre- and post-treated TiO2-based photoanodes prepared in the process of thermal oxidation offer far better performance in PECs than those which had not been treated.