Polyethylene glycol-modified sol-gel synthesis of ZnTiO3(n)- quartz composite microspheres for enhanced photocatalytic degradation of Reactive Brilliant Red X-3B

Zinc titanate-quartz composite microspheres were synthesized via a sol-gel route, and polyethylene glycol was used to reduce ZnTiO3 crystal aggregation and to promote the photocatalytic activity of the ZnTiO3(n)-SiO2 composites. The crystallite size of ZnTiO3 was found to decrease from 37.8 nm (ZnTiO3(0)-SiO2) to 27.2 nm (ZnTiO3(2.5)-SiO2) with increasing polyethylene glycol amount. Many free fine ZnTiO3 particles were obtained in the composites after the removal of polyethylene glycol during calcination. The bandgap energies of ZnTiO3(0)-SiO2 , ZnTiO3(0.5)-SiO2 , ZnTiO3(1.5)-SiO2 and ZnTiO3(2.5)-SiO2 were measured as 3.49, 3.71, 3.89 and 3.54 eV, respectively. Both the pore volumes and the surface areas of ZnTiO3(0.5)-SiO2 and ZnTiO3(1.5)-SiO2 were found to be enlarged compared to those of ZnTiO3(0)-SiO2. Polyethylene glycol can significantly enhance the photocatalytic activity of ZnTiO3(n)-SiO2 composites. In terms of hydroxyl radical production, the composites follow the sequence ZnTiO3(1.5)-SiO2 , ZnTiO3(0.5)-SiO2 , ZnTiO3(2.5)-SiO2 and ZnTiO3(0)-SiO2. The RBR X-3B degradation rate constants for ZnTiO3(1.5)-SiO2 , ZnTiO3(0.5)-SiO2 and ZnTiO3(0)-SiO2 were calculated as 0.02474, 0.02201 and 0.01777 min -1 , respectively. A total of 89.5% of RBR X-3B molecules were degraded on ZnTiO3(1.5)-SiO2 after 80 min of reaction, leading to the decomposition of major organic groups in the dye.

Automated summary

Zinc titanate-quartz composite microspheres were synthesized using a sol-gel method, and the addition of polyethylene glycol improved the photocatalytic activity of the composites. The size of the ZnTiO3 crystals decreased with increasing polyethylene glycol content, and the ZnTiO3 particles were well dispersed in the composites. The composites exhibited a wider bandgap and enhanced photocatalytic activity compared to pure ZnTiO3.