Photocatalytic oxidation activities of TiO2 nanorod arrays: A surface spectroscopic analysis

• Characterization of Ti3+ state or oxygen vacancy in TiO2 nanorod by XAS and XPS
• Variation of Ti and O electronic states by the defect formation in TiO2 nanorod
• Evolution of Ti3+ defects on TiO2 nanorod arrays as increasing growth time
• Photocatalytic-oxidation on TiO2 nanorod arrays having Ti3+ defect sites

The correlation between the defect structures of hydrothermally grown TiO2 nanorods (TNR) and their photocatalytic activity has been investigated by using various surface spectroscopic analysis techniques including scanning transmission X-ray microscopy (STXM) and high-resolution photoemission spectroscopy (HRPES). Defect states related to Ti3+ and oxygen vacancies in TNR were observed when the growth time was over 90 min (i.e., those over 500 nm in height), and these TNR samples showed photocatalytic oxidation activity with respect to the molecules 2-mercaptoethanol (2-ME) or 2-aminothiophenol (2-ATP), also confirmed by HRPES. The presence of defect structures on the TNR influences on the electronic states of titanium and oxygen, and thus can improve the catalytic oxidation reactions.

Figure optionsDownload as PowerPoint slide