Water-resistant Fe–Ca–Ox/TiO2 catalysts for low temperature 1,2-dichlorobenzene oxidation

Authors: Xiaodong Ma, Jinshan Shen, Weiya Pu, Hongwen Sun, Qin Pang, Jie Guo, Ting Zhou, Huiqin Cao

Abstract:
Fe–Ca–Ox/TiO₂ composite catalysts were synthesized to develop a low-temperature and water-resistant technology for the catalytic oxidation of 1,2-dichlorobenzene (o-DCB), as a model of chlorinated volatile organic compounds. The composite catalysts were characterized by XRD, TEM, N₂ adsorption/desorption and H₂-TPR. Activity measurements were conducted in the range of 200–500^◦C, in both the presence and absence of water. It was found that the incorporation of FeOx on TiO₂ could significantly improve the catalytic activity, but the activity was remarkably inhibited over a broad temperature range centered at 300^◦C due to the existence of water. Simultaneous incorporation of Fe and Ca oxide (Fe–Ca–Ox) on TiO₂ could not only further improve the catalytic activity but also enhance the performance of waterresistance in the wet reaction. Among the tested catalysts, the catalyst with Fe–Ca–Ox loading of 7 wt% showed the highest catalytic activity. The total conversion of o-DCB could be obtained at 350^◦C, in both the dry and wet reaction. The catalytic oxidation of o-DCB over TiFeCa-7 followed first-order kinetics with an apparent activation energy of 32 kJ/mol. The surface acidity of the catalyst and the intermediate species in the reaction were investigated by in situ FTIR spectroscopy. It is proposed that o-DCB molecule should be preferentially adsorbed on the Lewis acid sites, forming partial oxidation products, which could be subsequently oxidized to form final products.

Keywords:
Chlorinated volatile organic compounds
1,2-Dichlorobenzene
Catalytic oxidation
Water-resistance
Fe–Ca–Ox/TiO₂

Published in: Applied catalysis A: General  (Volume 466, Pages 1-314, 10 September 2013)

Publisher: Elsevier  

ISSN Information: 0926-860X

Water-resistant Fe–Ca–Ox/TiO2 catalysts for low temperature 1,2-dichlorobenzene oxidation

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