【摘要】 采用化学络合溶胶-凝胶法，结合自蔓燃合成工艺制备了结构可控、分散性良好的 TiO₂纳米粉体．考察了原料组成、凝胶膨胀程度和温度机制对粉体结构、分散性的影响，用漫反射光谱测试了所制备粉体的光吸收性能，结果表明，将原料中氧化剂与还原剂的摩尔比从2增加到7，在600℃的煅烧温度下可以得到金红石含量在25%～68.2%之间的 TiO₂，这些结构不同的粉体粒度为30nm 左右；凝胶前驱体经过150℃充分膨胀炭化，能有效阻止胶粒间氢键的形成，并且能够防止因毛细管作用而导致的凝胶网络坍塌，从而得到单分散无团聚粉体：提高煅烧温度，金红石含量增多、颗粒粒度增大，800℃时出现团聚体；用该工艺制备的粉体的光吸收范围发生明显红移，与市售金红石型 TiO₂相比，反光率下降10%以上；金红石含量为55.5%的混晶型粉体显示出最好的光吸收性能。更多还原

【Abstract】 Highly dispersed TiO₂ nanometer powders with controlled structure were synthesized by chemicalcomplex sol-gel auto-igniting process.The initial oxidant/reductant molar ratio,swelling of gel and temperatureschedule were chosen as key variables for the controlled synthesis:by changing the initial oxidant/reductantmolar ratio from 2 to 7,TiO₂ having a particle size about 30 nm was obtained at 600℃ with a mass fraction ofrutile ranging from 25% to 68.2%;sufficient swelling and carbonizing of the gels at 150℃ removednon-bridging hydroxyl groups and broke down the hydrogen bonds between particles,so the formation of hardagglomerates was avoided;the mass fraction of rutile and particle size of TiO₂ increased with increasing of cal-cination temperature;agglomerates of TiO₂ were formed at 800℃.The optical absorption edges significantlyshifted to longer wavelengths in the UV-Vis diffuse reflectance spectra of the as-prepared TiO₂,and the reflec-tivity was about 10% lower than that of commercial TiO₂.It was found that the as-prepared TiO₂ with the optimalrutile fraction of 55.5% achieved the best optical absorption.更多还原