Fabrication and characterization of composition-gradient CuO/SiO2 composite aerogel

Abstract

With tetramethoxysilane as the silica precursor, CuCl2·2H2O as the copper–oxide precursor, acetonitrile as the solvent and gelled by PO via a sol–gel process, the CuO/SiO2 composite aerogel was fabricated. By adjusting the amount of CuCl2·2H2O, CuO/SiO2 composite aerogels with different molar ratio of Cu/Si such as 1, 5, 10, 20, 30 and 35 % was prepared. Finally, via a self-built device and sol-co-gelation technic, a continuous formation process was developed to fabricate the composition-gradient CuO/SiO2 composite aerogel. Density of these aerogels was about 200 mg/cm3, the composition-gradient CuO/SiO2 composite aerogel was cylindrical and about 2.5 cm in height. Scanning electron microscope was used to characterize its microstructure at different position. X-ray diffraction, energy dispersive spectrometer and Fourier transform infrared spectrometer were used to characterize its composition and composition distribution, the results showed that the cylindrical CuO/SiO2 composite aerogel’s molar ratio of Cu/Si changed from 31.06 to 4.43 % as the measure point from the bottom up, the whole sample displayed obvious composition-gradient.