CuO(CoO,MnO)/SiO_2纳米复合气凝胶催化剂载体的溶胶-凝胶法制备及成胶机理

PREPARATION AND GELATINATION MECHANISM OF CuO(CoO,MnO)/SiO_2 NANOCOMPOSITE AEROGEL AS CATALYST CARRIER BY THE SOL-GEL PROCESS

采用正硅酸乙酯(tetraethyl orthosilicate,TEOS)和Cu,Co,Mn的醋酸盐溶液,通过溶胶-凝胶法、常压干燥制备了过渡金属氧化物含量高达75%(质量分数)的CuO(CoO,MnO)/SiO2纳米复合气凝胶,对其成胶机理进行了分析。结果表明:制得的CuO(CoO,MnO)/SiO2纳米复合气凝胶具有SiO2气凝胶的纳米孔隙三维网络结构和高比表面积;当过渡金属醋酸盐与TEOS的比例不同时,Cu,Co和Mn能够与氧在网络结构中形成不同程度的—O—M—O—桥键连接;通过气凝胶的多孔网络分隔作用,可使更多过渡金属氧化物CuO,CoO和MnO的超细粒子均匀分散于CuO(CoO,MnO)/SiO2复合气凝胶或SiO2气凝胶骨架中。这种结构既有利于提高催化剂负载量,又能充分利用CuO,CoO和MnO的助催化作用,因此CuO(CoO,MnO)/SiO2纳米复合气凝胶可作为催化剂载体用于催化合成碳酸二苯酯及其它催化领域。

CuO(CoO,MnO)/SiO2 composite aerogels with transition metal oxides as high as 75%(in mass) were prepared by using tetraethyl orthosilicate(TEOS) and acetate of Cu,Co and Mn via the sol-gel process and ambient pressure drying technique,and the gelatination mechanism was investigated.The results show that the CuO(CoO,MnO)/SiO2 nanocomposite aerogels have nano-pores and a three-dimensional network structure as well as high specific surface areas.According to different proportions between acetates of transition ...