Preparation and Photocatalytic Properties of Nanosized La{sup}(3+) and Co{sup}(2+) Co-doped TiO{sub}2 by Microemulsions

摘要

La{sup}(3+) and Co{sup}(2+) co-doped titania nanoparticles were prepared from reacting TiOSO{sub}4, La(NO{sub}3){sub}3 and Co(NO{sub}3){sub}2 with NH{sub}4OH in water/Triton X-100/n-hexanol/cyclohexane microemulsions. The structure, surface morphology and the specific surface area of the samples were characterized. The photocatalytic efficiency of as-prepared TiO{sub}2 was tested by photodegrading methyl orange. The results showed that doping with La{sup}(3+) and Co{sup}(2+) could suppress the growth of TiO{sub}2 grains and increase the specific surface area; When the calcination temperature increased from 300°C to 900°C, the average crystallite size of the particles increased from 7.3nm to 35.6 nm and the specific surface area of the particles decreased rapidly from 205.5m{sup}2/g to 41.2m{sup}2/g. The synthesized amorphous particles were transformed into anatase phase at 300°C, and further into rutile phase at 900°C. UV-Vis diffuse reflectance spectrum revealed that La{sup}(3+) and Co{sup}(2+) co-doped TiO{sub}2 absorbed UV light and visible light, while pure TiO{sub}2 could only absorb UV light. In the experiments of photodegrading methyl orange, it was proved that La{sup}(3+) and Co{sup}(2+) co-doped TiO{sub}2 had high photocatalytic activity under UV light and visible light, while pure TiO{sub}2 showed photocatalytic activity just under UV light.