Grain-growth kinetics of rutile TiO2 nanocrystals under hydrothermal conditions

作者：Li GS; Li LP; Boerio Goates J; Woodfield BF^*

来源：Journal of Materials Research, 2003, 18(11): 2664-2669.

Rutile nanocrystals were directly prepared under hydrothermal conditions using TiCl4 as the starting material. The formation reactions proceeded by suppressing the crystallization of the other TiO2 polymorphs using a fixed concentration of 0.62 M [Ti4+]. With increasing reaction temperatures from 140 to 220 degreesC, rutile nanocrystals were found to grow from 5.4 to 26.4 nm in size, and by varying the reaction time from 2 to 120 h at 200 degreesC the particle size increased from 17 to 40 nm. The grain-growth kinetics of rutile TiO2 nanocrystals under hydrothermal conditions was found to follow the equation, D-n = k(0) x t x e((-Ea/RT)) with a grain-growth exponent n = 5 and an activation energy of E-a = 170.8 kJ mol(-1). The nanocrystals thus obtained consist of an interior rutile lattice and a surface hydration layer. With decreasing particle size, the hydration effects at the surface increase, while the rutile structure shows a lattice expansion and covalency enhancement in the Ti-O bonding.

• 出版日期2003-11