Sol-gel synthesis of porous gadolinium titanate photocatalyst for improved activity.

Polyethylene glycol was used in a sol-gel route to prepare gadolinium titanate. The crystallite sizes of pyrochlore Gd2Ti2O7 prepared at 800°C and 900°C were 34.2 and 40.0 nm, respectively. Pores were produced in the materials after removing the PEG1000 template. The bandgap energies of Gd2Ti2O7 decreased from 3.43 to 3.21 eV when the calcination temperature increased from 600°C to 900°C. The crystallized porous Gd2Ti2O7 had a low photoluminescence intensity. The samples prepared at low calcination temperatures had both a large pore volume and a high specific surface area, and the Brunauer-Emmett-Teller surface area decreased from 46.8 to 14.9 m2/g when the calcination temperature increased from 600°C to 900°C. Hydroxyl radical production and azo dye degradation proved the strongest photocatalytic activity of porous Gd2Ti2O7 calcined at 800°C. The Reactive Brilliant Red X-3B degradation efficiency was 43.5% after 30 min of reaction. [ABSTRACT FROM AUTHOR]