Effects of diethanolamine on the evolution of silver/titanium dioxide sol–gel process

Abstract

In order to clarify the effects of diethanolamine (DEA) in the silver (Ag)/titanium dioxide (TiO2) sol–gel process, sols with and without DEA, and films derived from these sols were prepared. The samples were investigated by X-ray diffraction, transmission electron microscopy, electron diffraction and optical absorption spectra. The results showed that metallic Ag clusters were formed in the sol with DEA and was absent in the sol without DEA. This indicated that DEA worked not only as the stabilizer but also as the reduce agent in Ag/TiO2 sol–gel process. After annealed, Ag metallic nanoparticles were generated in the films derived from both the sols with and without DEA. The particles in the films derived from the sol with DEA were smaller than those from the sol without DEA. This can be ascribed to the limitation of the growth of Ag cluster formed in the sol with DEA during heat treatment. Mechanisms for the formation of metallic Ag in the Ag/TiO2 sols and films were discussed. The effects of DEA in the sols and films were studied in detail.