Preparation and microstructure of CuO-CoO-MnO/SiO2 nanocomposite aerogels and xerogels as catalyst carriers

CuO-CoO-MnO/SiO2 nanocomposite aerogels and xerogels were prepared using tetraethyl orthosilicate (TEOS) as Si source, and aqueous solution of Cu, Co and Mn acetates as the precursor via sol-gel process, CO2 supercritical drying (SCD) technique or ambient pressure drying technique. The microstructure of the CuO-CoO-MnO/SiO2 nanocomposite aerogels and xerogels were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The specific surface area, pore size and pore size distribution of the nanocomposite aerogels and xerogels were determined by the Brunauer-Emmett-Teller (BET) method. The results showed that CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous, with a pore size distribution of 2–50 nm, an average pore size of 19.4 nm, a specific surface area of 384.9 m2/g and a particle size distribution of 10–150 nm, whereas the pore size distribution of CuO-CoO-MnO/SiO.7–128.6 nm, the average pore size is only 9.9 nm, the specific surface area is only 99.1 m2/g, and the particle size distribution is 100–500 nm. The structure of CuO-CoO-MnO/SiO2 nanocomposite aerogels is favorable to increase the loading of catalysts.