Promotion of Cobalt Oxide Catalysts by Acid-Etching and Ruthenium Incorporation for Chlorinated Voc Oxidation

Abstract

Ru-promoted cobalt oxide catalysts were prepared by a synthesis route based on the Kirkendall effect followed by an acid treatment and optimised Ru impregnation. The resulting samples were characterised by N2 physisorption, X-ray diffraction, scanning electron microscopy techniques, X-ray photoelectron spectroscopy, temperature programmed techniques and evaluated in the oxidation of 1,2-dichloroethane. Ru addition improved the oxygen mobility as well as the amount of Co2+ and Oads species at the surface by the formation of the Ru-O-Co bond, which in turn governed the performance of the catalysts in the oxidation reaction. Moreover, the acid-etching favoured the dispersion of the Ru species on the surface of the catalysts and strengthened the interaction among the noble metal and the cobalt oxide. Thus, the resulting catalysts were not only active, as the chlorinated pollutant was efficiently converted into deep oxidation products at relatively low temperatures, but also quite stable when operating for 120 hours.

Keywords: Cobalt oxide, ruthenium dispersion, acid-etching, 1, 2-dichloroethane, stability