Sol-gel Preparation of Photocatalytic Porous Strontium Titanate using PEG4000 as the Template

PEG4000 was used as the pore forming template to prepare porous strontium titanate using tetrabutyl titanate and strontium nitrate as initial precursors in a sol-gel process. The addition of PEG4000 can obviously result in porous structure in the strontium titanate samples with high surface area. Particle size of the samples decreases constantly with increasing PEG4000 amount. SrTiO3 and SrCO3 gradually take the place of Sr2TiO4 and anatase TiO2 in the materials prepared using increasing amount of PEG4000. Fine SrTiO3 crystals form through sol-gel process using high template amount in the precursor. The XPS results are in close accordance to the phase transformation from Sr2TiO4 to SrTiO3 after the addition of PEG4000 in the precursor. The maximum photocatalytic activity is obtained on the sample prepared using 1.5 g of PEG4000, on which 40.0% of methyl orange is degraded after 30 min of irradiation. Methyl orange degradation rate increases drastically with the increase of photocatalyst amount when porous strontium titanate concentration is less than 1000 mg/l. The porous strontium titanate shows much higher photocatalytic activity than the sample prepared without using PEG4000.