溶胶-凝胶法合成人造金红石超细颗粒

Synthesis of Rutile Ultrafine Particles via Sol-Gel Process

探讨了文题的方法,研究了反应物与催化剂浓度对凝胶化速度、颗粒大小及分布的影响。结果表明,烷氧基钛在醋酸催化作用下水解和缩聚可制备均匀透明的块状凝胶,经干燥、焙烧得到金红石型的TiO_2超细颗粒。颗粒平均粒度随水含量增加而下降;随水解底物浓度的增加而下降,然后略有上升;随醋酸浓度增加而降低。醋酸根离子浓度不仅作为催化剂,而且作力能形成Ti(OC_4H_9)_x(Ac)_y络合物的配位体而起作用,改善了颗粒粒度的均匀性。凝胶透明度与颗粒的粒度及其分布有关,而与凝胶化时间无关。本法制备的TiO_2颗粒粒度细(20～200nm)、单分散性好且纯度高。

The methods for synthesis of futile ultrafine particles via Sol-Gel process have been studied. The paper represents a systematic study of how the concehtration of reactants and catalyst affect the gelation rate and the particle size. Experimental results showed that the monolithic gets could be reproducibly obtained when the hydrolysis of titanium alkoxides was performed in the presence of acetic acid. Further-more, futile ultrafine particles could be prepared repeatedly by vacuum drying and calcination. The average particle size decreased and then increased slightly with increasing initial concen-tration of Ti (OC_4H_9)_4, and decreased with larger amount of H_2O, but decreased with increasing concentration of HAe.Ac^-acts not only as a catalyst, butas a ligand to form Ti (OC_4H_9)_x(Ac)_y complex, which is able to promote particle size uniformity.The particles synthesized by Sol-Gel method are fine (20～200 nm), uniform and of high-purity.