Thermal Evolution Of Structural, Optical And Photocatalytic Properties Of TiO2 Nanostructures

University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110078, India

Adv. Mater. Lett., 2015, 6 (10), pp 924-929

DOI: 10.5185/amlett.2015.6000

Publication Date (Web): Sep 18, 2015

Copyright © IAAM-VBRI Press

E-mail:smiuac@gmail.com

Abstract

Nanostructures of TiO₂ were synthesized by a facile sol-gel method using pentanol as solvent. The effects of thermal annealing on the structural, optical and photocatalytic properties of as-synthesized TiO₂ nanostructures have been studied using X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy and UV-visible absorption spectroscopy. XRD and Raman spectroscopy results revealed that the synthesized TiO₂ nanostructures exist in anatase phase for annealing at temperatures up to 300 ^oC, while annealing at 600 ^oC led to the formation of TiO₂ nanostructures in anatase/rutile mixed-phase. AFM studies revealed the presence of TiO₂ nanorods, which showed a small decrease in aspect ratio upon annealing. The photocatalytic activity of nanostructured TiO₂ samples was evaluated through sun light driven degradation of methylene blue (MB) dye in water. TiO₂ nanorods in anatase/rutile mixed-phase in the sample annealed at 600 ^oC were found to exhibit the highest photocatalytic activity towards degradation of MB dye. The mechanism underlying the enhanced photocatalytic activity of TiO₂ nanostructures in anatase/rutile mixed-phase is tentatively proposed.

Keywords

TiO_2, nanostructures, photocatalysis, methylene blue.