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Author Anitha, B. ♦ Khadar, M. Abdul ♦ Banerjee, Alok
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ COBALT IONS ♦ COBALT OXIDES ♦ DOPED MATERIALS ♦ ELECTRON SPIN RESONANCE ♦ IMAGES ♦ MAGNETIC PROPERTIES ♦ NANOSTRUCTURES ♦ OXIDATION ♦ PARAMAGNETISM ♦ PEROXIDES ♦ SPECTRA ♦ STRUCTURE FACTORS ♦ SURFACES ♦ TITANIUM OXIDES ♦ TRANSMISSION ELECTRON MICROSCOPY ♦ X-RAY DIFFRACTION
Abstract Doping in nanocrystals is a challenging process because of the self- purification mechanism which tends to segregate out the dopants resulting in a greater dopant concentration near the surface than at the interior of nanocrystals. In the present work nanocrystals of TiO{sub 2} doped with different atom % of Co were synthesized by peroxide gel method. XRD analysis confirmed the tetragonal anatase structure and HRTEM images showed the rod-like morphology of the samples. Raman modes of anatase phase of TiO{sub 2} along with weak intensity peaks of Co{sub 3}O{sub 4} for higher Co dopant concentrations were observed for the samples. EPR measurements revealed the presence of cobalt in +2 oxidation state in the TiO{sub 2} matrix. SQUID measurements indicated paramagnetic behavior of the Co doped TiO{sub 2} nanocrystals. The paramagnetic behavior is attributed to an increased concentration of Co{sup 2+} ions and an increased presence of Co{sub 3}O{sub 4} phase near the surface of the TiO{sub 2} nanocrystals due to self-purification mechanism. - Graphical abstract: Variation of the intensity ratios of XRD peaks as a function of atomic ratio of Co. Inset: variation of structure factor for (101) reflection as a function of atomic ratio of Co. Display Omitted - Highlights: • Co doped TiO{sub 2} nanocrystals were synthesized by peroxide gel method. • HRTEM images showed Co doped TiO{sub 2} nanocrystals to be rod-like. • EPR spectra showed +2 oxidation states for Co in the samples. • Co doped TiO{sub 2} nanocrystals showed paramagnetic behavior.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-07-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 239


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