快速制备高掺杂CuO/SiO2复合气凝胶

通过环氧丙烷预反应法, 以乙腈为溶剂快速制备了高掺杂的氧化铜/二氧化硅复合气凝胶. 在典型的合成过程中, 将正硅酸甲酯(TMOS)、乙腈、去离子水和环氧丙烷混合进行预反应, 然后将该溶液与氯化铜的乙腈-水溶液混合并添加环氧丙烷, 在35℃烘箱中静置0.5 h 后转化为湿凝胶, 再经过CO₂超临界流体干燥和热处理即可获得黑色块状CuO/SiO₂复合气凝胶. 最终气凝胶样品密度约为180 mg·cm^-3, 比表面积高达625 m2·g^-1, 平均掺杂比为19.91%±2.42% (Cu:Si 摩尔比), 压缩模量为1.639 MPa, 具有成型性好、分散均匀等优点,是良好的背光源靶材料. 本论文还通过对比实验对凝胶化过程的机理进行分析, 结果表明, 通过改变溶剂和采用环氧丙烷预催化均衡了两种不同前驱体的反应速率, 实现了共凝胶的目的. 此外, 该方法还有望为其它金属氧化物/二氧化硅复合气凝胶的制备提供新思路.

Rapid Preparation of Highly Doped CuO/SiO2 Composite Aerogels

Highly doped CuO/SiO₂ composite aerogels were prepared via a propylene oxide pre-reaction method with acetonitrile as solvent. In a typical synthesis process, tetramethoxysilane (TMOS), acetonitrile, deionized water, and propylene oxide were mixed together for pre-reaction. The solutions were then mixed with a CuCl2 acetonitrile-water solution, with added propylene oxide. The mixed solutions were transformed to the wet gels after being kept in the oven for 0.5 h at 35℃. The dark monolithic CuO/SiO₂ composite aerogels were obtained after drying with supercritical CO₂ and following thermal treatment. The density, specific surface area, average doping concentration, and compression modulus of the final aerogel samples were about 180 mg·cm^-3, 625 m²·g^-1, 19.91%± 2.42% (Cu:Si molar ratio), and 1.639 MPa, respectively. The aerogels, which were ideal materials for backlight targets, featured good formability and uniform dispersion. The gelation mechanism was also discussed by comparing our typical synthetic process with reference experiments. The results demonstrated that the reaction rates of the two precursors were balanced by changing the solvent and using the propylene oxide pre-reaction method, which realized the co-gelation. In addition, the method may inspire new synthetic ideas for preparation of other metal-oxide/silica composite aerogels.