Sol-gel synthesized ZnTiO3/SiO2 composite photocatalyst for Reactive Brilliant Red X-3B degradation

Abstract ZnTiO3 was supported on quartz microspheres to reduce ZnTiO3 particle aggregation and to enhance the photocatalytic activity of ZnTiO3. The distribution of ilmenite phase ZnTiO3 on quartz microspheres was found to reduce the ZnTiO3 crystallite size from 40.4 nm to 19.9 nm. The commonly large ZnTiO3 particles in pure ZnTiO3 can hardly exist in χZnTiO3/SiO2 composites. The bandgap energy of ZnTiO3 is enlarged after support on quartz microspheres. The bandgap energies of 20ZnTiO3/SiO2, 50ZnTiO3/SiO2, 80ZnTiO3/SiO2 and pure ZnTiO3 were determined to be 3.42, 3.38, 3.08 and 2.93 eV, respectively. The pore volume and the BET surface area of χZnTiO3/SiO2 composites were several times larger than that for both quartz microsphere and ZnTiO3. The hole-electron recombination efficiency is reduced after supporting the ZnTiO3 on quartz microspheres. The photocatalytic activity of χZnTiO3/SiO2 composites is in the sequence 50ZnTiO3/SiO2 > 80ZnTiO3/SiO2 > 20ZnTiO3/SiO2 > ZnTiO3. The RBR X-3B degradation rate constants for ZnTiO3, 20ZnTiO3/SiO2 and 50ZnTiO3/SiO2 were determined to be 0.01016, 0.02271 and 0.02653 min−1, respectively. The RBR X-3B degradation efficiency in the presence of 50ZnTiO3/SiO2 reaches 91.7% after 80 min of reaction.