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Titania–silica composites (TSC) with various Ti/Si ratios were synthesized via sol–gel process using less
expensive precursors; sodium silicate solution as a silica source and titanium oxychloride as a titania source.
The influence of varying Ti content in the composites was examined by FTIR, SEM, TEM, DTA/TGA, N2
physisorption studies, XRF and XRD. The BET surface area of the raw materials increased with increasing Ti/Si
ratio up to 2.9 (461 m2/g) but further increase of Ti content beyond that ratio yielded compositeswith decreased
surface area. The effect of aging evaluated in the samplewith Ti/Si=2.9 revealed that aging the composite for 2 h
yields titania–silica powderwith the highest surface area (461 m2/g). The FTIR analysis displayed the presence of
a vibration band at 945 cm−1, assignable to hetero linkage of the Si–O–Ti depicting the incorporation of TiO2 into
SiO2 to form a composite.Moreover, photodegradation of methyl orange (MO) by the samples calcined at 800 °C
showed that the TSC-5-800 (Ti/Si=5.6) exhibited the highest maximum photocatalytic activity of all the
composites. |
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