Synthesis and comparative characterization of functionalized nanoporous silica obtained from tetrachloro- and tetraethoxysilane by a sol-gel method.

Functionalized silica supports were synthesized under various conditions using tetraethoxysilane (TEOS) and silicon tetrachloride (STC) as precursors by the sol-gel method. The polyethylene glycol with a molecular weight of 1500 was used as a structure-controlling agent. The use of STC as a SiO₂ precursor allowed getting a higher specific surface area in comparison with TEOS. The influence of hydrothermal and acidic treatment on the specific surface area of the obtained structures was studied. The concentration of silanol groups was evaluated applying diffuse reflectance infrared Fourier transform spectroscopy. SEM micrographs showed that the use of toluene as an additional solvent of polyethylene glycol led to the formation of the agglomerates from sphere-shaped SiO₂, meanwhile, the use of hexane led to the formation of a rhombohedral cell structure. [ABSTRACT FROM AUTHOR]