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

Abstract

The correlation between the defect structures of hydrothermally grown TiO2nanorods (TNR) and theirphotocatalytic activity has been investigated by using various surface spectroscopic analysis techniquesincluding scanning transmission X-ray microscopy (STXM) and high-resolution photoemission spec-troscopy (HRPES). Defect states related to Ti3+and oxygen vacancies in TNR were observed when thegrowth time was over 90 min (i.e., those over 500 nm in height), and these TNR samples showed photocat-alytic 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 elec-tronic states of titanium and oxygen, and thus can improve the catalytic oxidation reactions.