Hydrophobic GeO₂ Aerogels by an Epoxide-Induced Process

This article reports a new straightforward method for producing hydrophobic GeO₂ aerogels in a one-pot synthesis. For the first time, the epoxide-induced sol-gel process was combined with the co-precursor method to create hydrophobic aerogels. The application of a complex of analytical methods like SEM, TEM, low-temperature nitrogen adsorption-desorption, SAXS and contact angle measurements enabled us to determine that varying the GeCl₄:(C₂H₅)₂GeCl₂ ratio allows for targeted adjustments in the morphology, porous structure, and surface properties of aerogels. As the proportion of (C₂H₅)₂GeCl₂ grows, the surface area increases from 45 to 123 m²∙g^-1 and the contact angle changes from 22.1 to 140.1°. Luminescent properties of the hydrophobic GeO₂ aerogels are reported for the first time, and it is established that the ratio of green and blue bands in the luminescence spectra when excited under 390 and 235 nm varies depending on the GeCl₄:(C₂H₅)₂GeCl₂ ratio used for the aerogel preparation.