Optical investigations of Ag/CeO2 nanocomposites

Abstract

Silver/ceria (Ag/CeO2) nanocomposites were pre- pared from Ce(NO3)3 6H2O, AgNO3, and NH4OH with different molar ratios through a hydrothermal process, and then were completed by carrying out the precursors calcining at 750 °C for 2 h under air atmosphere. Below 1 % of Ag con- centration in Ag/CeO2 nanocomposites, the Ag crystalline structure does not appear. XRD and TEM results show evidence of two different effects (the agglomeration and the barrier effects) governing the process of crystal growth. HR- TEM image and EDX elemental analysis of the Ag/CeO2 nanocomposite confirmed that isolated Ag nanocrystals are dispersed in the CeO2 matrix. The red shifts are attributed to the quantum confinement effect and the valence change of the Ce+ ions. Ag nanoparticles can help to improve the absorption of visible light, enhancing the absorption intensity of Ag/CeO2 nanocomposite. These results are of great significance for the control of microstructure, crystallinity, and applications for the development of nanocomposite ma terials.