关键词: TiO₂, 晶型, 光致变色, 甘油, Ti³⁺

Abstract: The photochromic of nano-TiO₂ with different crystals and the hydrous TiO₂ in the glycerol environment were systematic studied in this paper. Experimental results showed that，amorphous TiO₂（hydrous TiO₂）has the most obvious discoloration，while rutile nano-TiO₂ has no obvious coloration，the degree of discoloration of anatase nano-TiO₂ is between rutile and amorphous，the mixed crystals（rutile and anatase）nano-TiO₂ is weaker than anatase but stronger than rutile. The samples were characterized by X-ray photoelectron spectroscopy（XPS）and UV-visible（UV-vis），and the results indicated that the Ti³⁺ existed in the colored sample and the visible absorption spectrum of samples were significantly different before and after colored. The double-injection mechanism and the small polaron model were used to describe the photochromic mechanism of TiO₂. The electron-hole recombination rate effected on the Ti³⁺ formation and the effects of glycerin for TiO₂ photochromic phenomenon were investigated in this paper. The formation rate of Ti³⁺ decreased with the increasing of the electron-hole recombination rate，which leaded to the weakening of the color. The glycerin could promote the photochromic of TiO₂..

Key words: titanium dioxide, crystal, photochromic, glycerin, Ti³⁺