Surface passivation of CeO 2 catalyst and its ultraviolet screening effect

Abstract

A new strategy was attempted to fabricate CeO 2 nanoparticles using the surface fluorination technique to control the particle size and suppress the catalytic activity. The fluorinated CeO 2 nanoparticles are fully characterized with XRD, XANES , UV-vis spect troscopy, HR-TEM, XPS along with the evaluation of photo and thermal catalytic activitis e es. XRD patterns were not affected by surface fluorination. That is to say, the crystalline str ucture of CeO 2 was not deteriorated upon fluorination. The TEM analysis showed that the fluorina ted CeO b 2 nanoparticles with the primary particle size of 7 nm could be prepared. According to the X-ray absorption near edge structure (XANES) analysis, overall XANES spectrum was not changed upon fluorination, suggesting that the local structure of fluorinated CeO 2 resembled that of the starting CeO 2 nanoparticles. It was also revealed that both photo and thermal catalytic activities could be almost totally suppressed at the fluorination level of ca. 6.0 wt%. It is suggested that the selective surface fluorination with fluoride could lead to fluorinated CeO 2 nanoparticles, which could be applied to new fields such as the cosmetics industries. Copyright © 2011 American Scientific Publishers All rights reserved.