Dandapat, Anirban and De, Goutam (2012) Host-mediated synthesis of cobalt aluminate/gamma-alumina nanoflakes: a dispersible composite pigment with high catalytic activities. ACS Applied Materials & Interfaces, 4 (1). pp. 228-234. ISSN 1944-8244

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Cobalt aluminate/gamma-alumina (CoAl2O4/gamma-Al2O3) nanocomposite pigment with mesoporous structure has been synthesized. The method simply involves adsorption of Co2+ ion on the surface of a commercially available boehmite (AlOOH) powder followed by the reaction of Co2+ and AlOOH at relatively low temperature (500 degrees C) to obtain CoAl2O4/y-Al2O3 composite nanopowders. The formation of gamma-Al2O3 from boehmite induces the in situ generation of isostructural CoAl2O4 (both crystallize as cubic spinel) at such a low temperature. The obtained intense blue powder of optimal composition (53.6 wt % CoAl2O4 in gamma-Al2O3) can be dispersed in glycerol and characterized by UV visible, X-ray diffraction, Raman spectroscopy, TEM, and nitrogen sorption analyses. Raman studies confirm the formation of CoAl2O4 phase in gamma-Al2O3. TEM studies reveal the formation of flake shaped (5-10 nm in width and 10-25 nm in length) nanopowders, and these flakes are assembled to form mesoporous structure. The specific surface area, total pore volume and average pore diameter of this powder are estimated to be similar to 118 m(2) g(-1), 0.1375 cm(3) g(-1), and 4.65 nm, respectively. This composite nanopowder has been used as an active catalyst for the decomposition of H2O2 at room temperature and the decomposition follows the first order kinetics with rate constant value close to 2.3 x 10(-2) min(-1). This pigment nanopowder can be reused for several cycles without noticeable degradation of its original catalytic activity.

Item Type: Article
Uncontrolled Keywords: Host-mediated synthesis; CoAl2O4/gamma-Al2O3 composite nanopowder; Dispersible pigment; Reusable catalyst; Self-cleaning pigment
Subjects: Engineering Materials
Divisions: Nano-Structured Materials
Depositing User: Bidhan Chaudhuri
Date Deposited: 28 May 2012 11:42
Last Modified: 28 May 2012 11:42
URI: http://cgcri.csircentral.net/id/eprint/1436

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