摘要
采用环氧丙烷预反应法合成均匀金属氧化物/二氧化硅复合气凝胶,其中二氧化硅为凝胶主要组分,不同的胶体颗粒相互交联形成均匀的共凝胶网络。通过预反应和不同溶剂体系的选择,2种不同前驱体的水解和缩聚速率得到有效平衡,从而这种均匀的凝胶网络经过超临界干燥后收缩相对较小,且凝胶网络中金属和硅摩尔比n(M):n(Si)在一定范围内能够准确控制。这种合成的气凝胶通过一系列物理方法用来表征,例如,扫描电子显微镜(SEM),透射电子显微镜(TEM),傅里叶红外光谱(FTIR)和比表面积分析(BET)。最终不同样品的密度分布在100mg·cm-3到600mg·cm-3范围内,并且比表面积大部分大于300m2·g-1,甚至高达1000m2·g-1。金属氧化物在凝胶网络中才掺杂量与理论值相比相对准确尽管有少量的偏差,这使得这种新型材料在许多特殊量化实验研究中有潜在的应用,如作为一种背光源靶用于X射线转换实验。更重要的是,这种合成凝胶方法尤其适合于低价金属氧化物/二氧化硅复合气凝胶的制备。
We have demonstrated the synthesis of homogeneous metal-silicon mixed-oxide composite aerogels via a propylene oxide pre-reaction method, in which different colloidal particles crosslinked together into uniform co-gelation frameworks with silica acting as the major phase. Through pre-reaction and selective solvent system, the hydrolysis and condensation rates of two different precursors have been efficiently balanced, and uniform composite aerogel networks without large shrinkage after supercritical drying were obtained. The doping mole ratio of metal to silicon(n(M):n(Si)) could be accurately controlled within a certain range. In addition, a variety of physical characterizations about synthesized aerogels were performed, such as scanning electron microscope(SEM), transmission electron microscope(TEM), the fourier transform infrared spectrometer(FTIR), and Brunaur-Emmett-Teller(BET) method. The densities of different samples were distributed in the range from 100 mg·cm-3 to 600 mg·cm-3, and the specific area was mostly above 300 m2·g-1, even as high as 1000 m2·g-1. Comparing with theoretical value, the final element ratio is relatively accurate though with slight deviation, increasing the possibility in some special quantified study like X-ray conversion experiment as the ideal backlight target. More importantly, the described synthesis method was especially suitable for preparation of low-valent metal-silicon mixed-oxide composites.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2016年第S1期530-535,共6页
Rare Metal Materials and Engineering
基金
National Natural Science Foundation of China(51102184,51172163)
National High Technology Research and Development Program of China(2013AA031801)
National Key Technology Research and Development Program of China(2013BAJ01B01)
Shanghai Municipal Science and Technology Commission Nano Special Project,China(12nm0503001,11nm0501600)
Science and Technology Innovation Fund of Shanghai Aerospace,China(SAST201254,SAST201321)
关键词
复合气凝胶
预反应
共凝胶网络
背光源靶
composite aerogels
pre-reaction
co-gelation frameworks
backlight target
