Ultrathin TiO₂(B) Nanosheets as the Inductive Agent for Transfrering H₂O₂ into Superoxide Radicals

Abstract

A reflux method to synthesize ultrathin polycrystalline TiO₂(B) nanosheets (NSs) which are assembled by single crystals, and further stacked into nanoflower structures, is described. On the basis of the theoretical calculations and experiments, H₂O₂ can easily substitute the ethylene glycol adsorbed on the surface of TiO₂(B) NSs, forming H₂O₂-NS due to the lower adsorption energy and the unique structural features of ultrathin TiO₂(B) nanosheets. TiO₂(B) NSs and the H₂O₂ system can be accelerated to generate superoxide radicals under heat or light and thus exhibit a great degradation property on dye molecules; the total organic carbon (TOC) removal rate was 6 times higher than that for H₂O₂ alone. Meanwhile, TiO₂(B) NSs and the H₂O₂ system have a good application on the selective oxidation due to the reactive species of superoxide radicals avoiding overoxidization of benzyl alcohol. The conversion of benzyl alcohol oxidized to benzaldehyde in water solution under low temperature and atmospheric pressure was 51.13%, while the selectivity was close to 100%. We believe that the present findings will provide valuable methods for highly efficient generation of superoxide radicals and broaden their applications in catalysis.