Catalytic oxidation of 1,2-dichlorobenzene over CaCO3/-Fe2O3 nanocomposite catalysts

Authors: Xiaodong Ma, Quan Sun, Xi Feng, Xuan He, Jie Guo, Hongwen Sun, Huiqin Cao

Abstract:
CaCO₃/-Fe₂O₃ nanocomposites were synthesized by one-pot method to develop a low-cost and environmentally friendly technology for the catalytic oxidation of 1,2-dichlorobenzene (o-DCB), a model of chlorinated volatile organic compounds. The nanocomposites were characterized by FAAS, XRD, N2 adsorption/desorption, TEM and XPS. Activity measurements were conducted in the range of 200–500 ◦C, in both the presence and absence of water. Among the tested catalysts, the nanocomposite with 9.5 mol% Ca showed the highest catalytic activity, which could be attributed to the promoting effect of CaCO₃ on -Fe₂O₃ with smaller crystallite size. Experimental results in the presence of water indicated that, due to the competitive adsorption of water on the active sites, there was a local minimum of catalytic activity at 350 ◦C. In situ FTIR experimental results revealed the presence of phenolate, catecholate, o-benzoquinone, carboxylate and anhydride type species on the surfaces of the catalysts during the oxidation of o-DCB. Spectral evidence discovered that the formate species were more prone to being formed on the surface of nanocomposite with 9.5 mol% Ca and then were further oxidized to CO, which directly lead to high activity of the catalyst. A mechanism involving dissociative adsorption of o-DCB on the surface of catalyst was proposed.

Keywords:
Chlorinated volatile organic compounds
1,2-Dichlorobenzene
Catalytic oxidation
CaCO₃
Fe₂O₃
 

Published in: Applied catalysis A: General  (Volume 450, Pages 1-274, 15 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Catalytic oxidation of 1,2-dichlorobenzene over CaCO3/-Fe2O3 nanocomposite catalysts

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