量子尺寸纳米TiO_2的水热制备及光催化性能

Hydrothermal preparation and photocatalytic properties ofquantum size TiO_2 nanoparticles

在钛酸丁酯和乙醇体系下,利用水热法制备了平均粒径为4～10 nm的量子尺寸锐钛矿型纳米二氧化钛粉末,并研究了此粉末的光催化活性和晶粒粒径、荧光发射光谱的关系.结果表明: 制备的纳米二氧化钛粉末在粒径为8～9 nm时光催化活性最好,当晶粒粒径再减小以后,由于表面活性的增加导致晶粒表面羟基的增加,成为电子和空穴的复合中心而使活性降低.同时此粉末的荧光发射光谱中并没有发现荧光峰位随着晶粒粒径变小而发生位移,并且荧光发射光谱峰的强度和光催化活性之间没有成比例的关系.

Anatase TiO2 nanoparticles were prepared by hydrothermal synthesis method with titanium n-butoxide and ethanol as initial reagents. The average grain size of the anatase TiO2 nanoparticles varied from 4-10 nm. Study of the dependence of photocatalytic property on the nanoparticle size and fluorescence spectrascopy show that the photocatalytic activities of the TiO2 nanoparticles with average grain sizes of 8-9 nm are better than those of other sizes. With the surface activity of nanosized titanium dioxide increasing, the hydroxyl groups increase in grain surfaces. The obtained surface hydroxyl groups are abundant to facilitate the recombination of electron and hole and led to the decreasing photocatalytic activity of the nanoparticles. The fluorescence emission peak positions don't shift when the sizes of titanium dioxide change. The intensities of fluorescence emission spectra are not in proportion to the photocatalytic activities of titanium dioxide nanoparticles.