Photocatalytic degradation of Red 2G on the suspended TiO2-hollow glass sphere

Anatase TiO2 was synthesized on Hollow glass spheres (HGS) by a sol-gel method in this work. TiO2/HGS composite (70% HGS + 30% TiO2) could be suspended in water to facilitate light absorption, and the particles were readily separated from water since they floated on water surface after treatment. The oxidation state of titanium (Ti4+) in TiO2/HGS composite was as same as that in pure TiO2, while the binding energies of Ti2p(1/2) and Ti2p(3/2) orbitals of TiO2/HGS had a slight 0.3 eV shift to high energy end. Nano-sized TiO2 crystals were tightly adhered on HGS surface, while the thickness of TiO2 film might be several hundred nanometers. The electron-hole pairs formed in TiO2 had a little longer lifetime than the electron-hole pairs formed in TiO2/HGS, proven by the photoluminescence intensity of emitted photons. Red 2G azo dye was used to study the degradation activity. The photocatalytic activity of TiO2/HGS composite was comparable to the activity of pure TiO2 particles. 81% of the initial Red 2G molecules (Red 2G solution 50 mL, 40 mg/L) were decomposed on TiO2/HGS composite in 170 min.

Automated summary

Anatase TiO2 was synthesized on Hollow glass spheres (HGS) by a sol-gel method in this work, and the TiO2/HGS composite exhibited comparable photocatalytic activity to pure TiO2 particles in degrading Red 2G azo dye in water.