Articles
  • Formation kinetics of crystalline Ti1-xCrxO2 photocatalyst from its amorphous powder
  • E. D. Jeonga, S. M. Yua, J. H. Yoona, J. S. Baea, T. E. Honga, C. R. Chob, K. T. Limc, P. H. Borsed,* and H. G. Kima,*
  • a Busan Center, Korea Basic Science Institute, Busan 609-735, Korea. b Department of Nano Fusion Technology, Pusan National University, Pusan 609-735, Korea c Department of Imaging System Engineering, Pukyong National University, Busan 609-735, Korea. d Solar H2 PEC lab, International Advanced Research Centre for Powder Metallurgy and New Materials (ARC International), Balapur PO, Hyderabad, AP, 500 005, India.
Abstract
Amorphous powders of undoped and chromium-doped TiO2 were prepared by a sol-gel method. Corresponding crystalline (anatase/rutile) phases were obtained by thermally-induced transformation of these amorphous powders. The activation energies for crystallization and grain growth of crystalline TiO2 and Ti0.9Cr0.1O2 from respective amorphous counterparts were estimated from X-ray diffraction and differential thermal analysis studies. The activation energies required for grain growth in amorphous TiO2 and Ti0.9Cr0.1O2 samples, were 1.51 kJ/mol and 1.78 kJ/mol, respectively. The activation energies required for the phase transformation from amorphous to crystalline TiO2 and Ti0.9Cr0.1O2 were 132 kJ/mol and 153 kJ/mol, respectively. It has been clearly demonstrated that relatively a higher temperature is required for the phase transformation in amorphous Cr doped TiO2 than in amorphous TiO2. This can be attributed to the high energy required for the substitution of Cr at Ti site in the TiO2 lattice, which in turn also yields a smaller crystallite size during grain growth.

Keywords: TiO2, Activation energy, Cr-doped TiO2, Sol-Gel method.

This Article

  • 2012; 13(6): 672-676

    Published on Dec 31, 2012

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