The synthesis and characterization of germanium oxide aerogel

In the present work, we have shown the first detailed report of monolithic pure germanium oxide aerogel. The aerogels have been prepared by the sol–gel method and subsequent supercritical drying with carbon dioxide. The orthogonal tests with different molar ratios of reactants (Ge(OEt)4, H2O, EtOH, HCl) have been applied to analyze the influence of each reactant. The replacement of ethanol with other solvents resulted in immediate precipitation. A presumption was given for that phenomenon. Chemical and structural investigations of the as-synthesized aerogels have been performed by field-emission scanning electron microscope (FESEM), thermogravimetry (TG), fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD) and the Brunauer–Emmett–Teller (BET) method. The aerogels possessed a fine microstructure, a surface area of 155 m2/g and a high percentage of mesopores. TG analysis showed excellent thermal stability with very small weight loss. FTIR diagram demonstrated the complete hydrolysis of germanium ethoxide and the corresponding chemical bonds have been observed. The result from XRD indicated that the porous material exhibited outstanding hexagonal crystalline structure.