凝胶纳米氧化钛的Raman光谱研究

Raman Studies on Nanocrystal TiO_2 Gels

Conventional and low-frequency Raman spectra of series of anatase TiO2 gels,which were prepared by sol-gel method in diffrent conditions, were measured. Xerogel and aerogel TiO2 were prepared by natural dry and supercritical dry respectively.Conventional Raman Spectra show that the width of peaks of TiO2 was almost broaden linearly with its particle size decreased down to several nm and a few new peaks were observed. The phenomena can be explained as the effect of particle size and occurrence of new surface structure. It can be used as a method of determination of small particle size. Low-frequency Raman scattering shows that from the intensity of spectra, the fractal dimension of nanocrystal xerogels and aerogels can be obtained by comparing with the base intensity. Low frequency Raman peaks give the information of particle size, acoustic velocity and polydispersibility about gel samples. More detailed woks were undergoing in our laboratory.