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Journal of Nanomaterials
Volume 2012, Article ID 108369, 8 pages
Research Article

Formation of CoAl2O4 Nanoparticles via Low-Temperature Solid-State Reaction of Fine Gibbsite and Cobalt Precursor

1Department of Chemical Engineering, Faculty of Engineering, Center of Excellence on Catalysis and Catalytic Reaction Engineering, Chulalongkorn University, Bangkok 10330, Thailand
2Department of Chemical Engineering, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom 73000, Thailand

Received 13 July 2012; Revised 14 August 2012; Accepted 16 August 2012

Academic Editor: Alireza Khataee

Copyright © 2012 Natpakan Srisawad et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Nanocrystalline cobalt aluminate (CoAl2O4) was synthesized by the solid-state reaction method with cobalt chloride hexahydrate (CoCl2 · 6H2O) as the source of Co and gibbsite (Al(OH)3) as the source of Al, respectively. The effects of particle size of the starting fine gibbsite (0.6 and 13 μm) and calcination temperatures (450, 550, and 650°C) on the properties of CoAl2O4 were investigated by means of X-ray diffraction (XRD), thermogravimetry analysis and differential thermal analysis (TG/DTA), X-ray photoelectron spectroscopy (XPS), UV-visible absorption spectroscopy (UV-Vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Increasing of calcination temperature promoted the insertion amounts of Co2+ in alumina matrix in CoAl2O4 structure, which resulted in the brighter blue particles and increasing of UV spectra band. The lowest temperature for the formation of nanocrystalline CoAl2O4 particles was 550°C for the solid-state reaction of cobalt chloride and 0.6 μm fine gibbsite.