부산대학교 도서관

Water splitting using photoelectrochemical technology is an excellent way to generate clean hydrogen, for which TiO2 is regarded as the most promising photoanode because of its unique properties. The large band gap and high recombination rate of charge carriers, however, limit its solar-to-hydrogen conversion efficiency. Herein, we fabricated the reduced TiO2 nanotubes by electrochemical anodization technique followed by hydrazine treatment to create oxygen vacancies (or Ti3+ sites) in the sample. The samples were then characterized by XRD and FESEM for structural and morphological analysis, validating the formation of Titania nanotube arrays (TNTA). Absorbance spectra of hydrazine-treated samples showed the absorption edge at about 447 nm, which corresponds to a band gap of 2.67 eV. This reduction in the band gap may be due to the introduction of Ti3+ states beneath the conduction band, as confirmed by XPS spectra. Photoluminescence spectra depicted the presence of oxygen vacancies in the hydrazine-treated sample. The hydrazine treatment, as a result of the introduction of Ti3+ states, enhanced the photocurrent density of the sample without affecting its photostability. [ABSTRACT FROM AUTHOR]