In this study, the efficacy with which TiO₂/carbon nanomaterials composites enhance ⋅OH generation was investigated. Nano-assemblies comprising different proportions of TiO₂ and multi-walled carbon nanotubes, single-walled carbon nanotubes, or fullerol were synthesized by a low temperature hydration-dehydration process and characterized by TEM, XPS, and UV-vis. Photocatalytic performance enhancement of all the TiO₂/carbon nanomaterial composites was quantified by nitrobenzene degradation or MS2 bacteriophage inactivation under UVA irradiation. The photoreactivity of the composites with respect to nitrobenzene (NB) oxidation and MS2 bacteriophage inactivation was found higher than that of TiO₂ and the optimum composition determined, which was TiO₂ to SWCNT prepared at mass ratio of 50:1....[ Read more ]

In this study, the efficacy with which TiO₂/carbon nanomaterials composites enhance ⋅OH generation was investigated. Nano-assemblies comprising different proportions of TiO₂ and multi-walled carbon nanotubes, single-walled carbon nanotubes, or fullerol were synthesized by a low temperature hydration-dehydration process and characterized by TEM, XPS, and UV-vis. Photocatalytic performance enhancement of all the TiO₂/carbon nanomaterial composites was quantified by nitrobenzene degradation or MS2 bacteriophage inactivation under UVA irradiation. The photoreactivity of the composites with respect to nitrobenzene (NB) oxidation and MS2 bacteriophage inactivation was found higher than that of TiO₂ and the optimum composition determined, which was TiO₂ to SWCNT prepared at mass ratio of 50:1.

The role of single-walled carbon nanotubes (SWCNTs) and fullerol in enhancing photocatalytic activity of nanostructured composites was elucidated in this study. Probing tests employing hydroxyl radical scavengers showed that the surface-bound ⋅OH generation of SWCNTs was more than that of TiO₂. Using the hole scavenger, sodium oxalate at different concentration levels indicated that more photogenerated holes on TiO₂/SWCNT composites than TiO₂ along. The addition of Fe³⁺, an electron scavenger to both TiO₂/SWCNT and TiO₂/fullerol systems revealed the similar function of SWCNT and fullerol as an electron scavenger. The results indicated that SWCNT and fullerol altered the pathway of electrons photoexicited from TiO₂, suggesting electron capture by SWCNT and fullerol to retard TiO₂’s electron-hole recombination, consistent with the increased generation of H₂O₂ by the TiO₂/SWCNT or TiO₂/fullerol composites within the testing period.

In spite of the similarities of the roles SWCNT and fullerol played in TiO₂ photocatalysis enhancement, their enhancement over TiO₂ alone and durability varied because of their different structural, chemical and electrical properties. SWCNT proved to have a more significant enhancement over TiO₂ than fullerol. Additionally, due to the longer life span and better chemical stability, SWCNT appeared to be the preferable photocatalyst support.