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The textural properties of TiO2–SiO2 composites (TSCs) were successively enhanced using three
approaches; (1) washing the hydrogels with different solvents, (2) using surfactant and (3) forming
the TiO2 sol in ethanol medium. The sol–gel process was exquisitely used to form the composites using
cost effective precursors. Initially, the precipitated hydrogels were washed with water or alcohol to evaluate
the influence of washing on the dried hydrogels. Consequently, two composites were formed differently
in the presence of stearic acid (SA) as a surfactant and the other by forming TiO2 sol in ethanol
medium prior to reaction with silica source. The TSC powders were examined by XRD, N2 physisorption
studies, FTIR, TGA, SEM, XRF and HRTEM. The BET surface area of the sample obtained after washing the
hydrogels with ethanol (TSCE) was the largest (594 m2/g) while porosities of the composites obtained
using stearic acid as a surfactant (TSCSA, 0.96 cm3/g) and ethanol as a medium to form the TiO2 sol
(TSCES, 1.85 cm3/g) were relatively superior to those obtained under influence of changing washing solvent.
Photocatalytic decolorization of methylene blue by the composites calcined at 800 C revealed that
the TSCES-800 possessed the highest activity of all the composites due to its superior properties. |
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