Study of the Gelling Process for the Preparation of Tin Oxide Materials Based on Tin Tetrabutoxide

The gelling process in the preparation of tin oxide materials based on tin tetrabutoxide is studied. Sn(OBun)4 modified by two moles of acetylacetone (AcAc) has a stable six-member ring structure and is less susceptive to water. In a system with a lower molar ratio of acetylacetone to Sn(OBun)4 ([AcAc]/[Sn(OBun)4]<2.0) or a larger portion of water ([H2O]/[Sn(OBun)4]>2.5), colloidal suspension or white precipitation will take place. A system with molar ratios of both acetylacetone to Sn(OBun)4 and water to Sn(OBun)4 at 2.0 is transparent and olivaceous sol. As catalysts, hydrofluoric, hydrochloric, hydrobromic and acetic acids, and ammonia all accelerate the hydrolysis and condensation of Sn(OBun)4 during the sol-gel process. Light scattering measurement indicates that cluster size distribution in the sol system undergoes gradual broadening during the sol-gel transition.     

Sn(OBun)4溶胶体系稳定性的研究

研究了溶胶-凝胶法制备二氧化锡中以锡酸正丁酯为前驱体的溶胶体系的稳定性.通过乙酰丙酮化学改性正丁醇锡,控制水解,添加催化剂和改变溶剂等方法调整体系参数制备了稳定的溶胶体系.利用部分电荷模型计算了锡醇盐分子中电子在各个基团上的分布,预测了锡醇盐水解的变化趋势,实现了溶胶体系的凝胶时间从几小时到几个月的大跨度调控,为锡酸正丁酯溶胶-凝胶法制备二氧化锡材料打下了坚实的基础.     

Sn(OBun)4溶胶-凝胶法制备SnO2气凝胶

以锡酸正丁酯(Sn(OBun)4)为前驱体,利用溶胶-凝胶工艺和CO2超临界干燥技术制备了透明和半透明的单块SnO2气凝胶.这些二氧化锡气凝胶密度小,孔隙分布宽,比表面积高.SEM分析表明,这种气凝胶由尺寸不一的如棉花团一样的团块堆积而成,团块之间为大尺寸孔隙(＞50 nm),棉花团块内还具有细小的微孔(＜2 nm)和介孔(＜50 nm).TEM分析表明,在不同的放大倍数下,二氧化锡气凝胶具有相似的结构.