Polyethylene glycol in the sol-gel synthesis of zinc titanate for the improved photocatalytic degradation of an azo dye

Polyethylene glycol (PEG) was used to improve the activity of zinc titanate synthesized via a sol-gel route. The crystallization of zinc titanate was restrained with an increasing amount of PEG. The obtained ZnTiO3(n) samples were composed of fine ZnTiO3 particles. The bandgap energy of 2.93 eV was calculated for ZnTiO3, and the bandgap energies for ZnTiO3(0.5), ZnTiO3(1.5) and ZnTiO3(3.0) were calculated to be 3.25, 3.28 and 3.52 eV. ZnTiO3 and ZnTiO3(n) were classified as mesoporous materials, according to the N-2 adsorption-desorption isotherms (IUPAC type IV). ZnTiO3(1.5) had the largest BET surface area (8.0 m(2)/g) and the largest pore volume (0.0119 cm(3)/g). The binding energies of Zn2p, O1s and Ti2p electrons in zinc titanate were nearly unchanged after using PEG. PEG significantly enhanced the production of hydroxyl radicals in the sequence of ZnTiO3(1.5), ZnTiO3(0.5), ZnTiO3(3.0) and ZnTiO3. The activities of all ZnTiO3(n) samples were stronger than that of ZnTiO3, and the strongest activity was obtained for ZnTiO3(1.5).

Automated summary

Polyethylene glycol (PEG) was used to improve the activity of zinc titanate synthesized via a sol-gel route. The addition of PEG restrained the crystallization of zinc titanate and resulted in the formation of fine ZnTiO3 particles. The bandgap energy and structural properties of ZnTiO3(n) were affected by the amount of PEG used. The production of hydroxyl radicals was significantly enhanced with the addition of PEG, and among all the samples, ZnTiO3(1.5) exhibited the strongest activity.