煅烧温度对二氧化钛纳米晶性能的影响

Effect of the Calcining Temperatures on the Properties of Nanocrystalline TiO_2

研究了不同煅烧温度下，锐钛矿相、混晶和金红石相二氧化钛纳米晶的粒径、比表面积和吸收光谱的变化．经相同的温度煅烧后，金红石相二氧化钛纳米晶的生长速率和比表面积下降速率均大大高于锐钛矿相，表明高温反应或煅烧难以获得金红石相纳米晶．真空热处理的金红石相二氧化钛纳米晶可以保持较高的比表面积和较小的粒径，但易导致非化学配比、晶格缺陷并降低了粉体的性能．

The effect of calcining temperatures on the particle size coarsening, the specific surface area lowering and band gap blue shifting of nanocrystalline TiO2 in the anatase, mixed-phases, and rutile phase was investigated. The rate of the particle size coarsening and the surface area lowering of TiO2 in the rutile phase are much higher than that in the anatase phase. This result means that it is hard to prepare nanocrystalline TiO2 in the rutile by anatase-to-rutile transformation or reactions at high temperature. When nanocrystalline TiO2 in the rutile phase is heated under vacuum) it has higher surface area as well as in finer size than that of one calcined in the air, however, heating under vacuum always results in nonstoichiometry and crystal defect, which is detrimental to its applications.