Synthesis of SiO2–SnO2 gels in water free conditions

Abstract

A series of SiO2–SnO2 samples with various Sn/Si molar ratios (0.05–1.0) have been synthesized by the sol–gel technique from (Tetraethylorthosilicate) TEOS and Sn(CH3COO)4 precursors in water free conditions. The synthesis applied allowed obtaining the final product in monolithic (nonfractured upon drying) form with no use of drying control chemical additives. All samples are characterized by thermal analysis, XRD, and FTIR. The low temperature nitrogen adsorption measurements indicate the presence of both micro and mesopores. The samples containing less than 20 wt% of SnO2 show much higher surface area than SiO2 gel. The appearance of new bands at 1,048 and 882 cm−1 in the FTIR spectra could be related to stretching vibrations of the three dimensional Si–O–Sn network, which suggests that tin component has replaced silicon atoms in Si–O–Si structure.