Highly active behaviour of nanocrystalline Co3O4 from oxalate nanorods in the oxidation of chlorinated short chain alkanes

Several bulk CO3O4 were prepared from various synthesis routes including direct calcination of a cobalt salt, grinding followed by solid-state reaction and thermal decomposition of cobalt oxalate nanorods. The resulting oxides were examined in the gas-phase oxidation of a model chlorinated short chain alkane namely, 1,2-dichloroethane. The route based on cobalt oxalate nanorods allowed to obtain high surface CO3O4 nanoparticles with a crystallite size as low as 13 nm, which exhibited both enhanced reducibility and oxygen uptake capacity at low temperatures when compared with the other prepared Co3O4 samples. As a result, this nanosized oxide converted the chlorinated feed at the lowest temperatures with an excellent selectivity to CO2. Conversion to deep oxidation products was complete (CO2, HCl and Cl-2), and no appreciable deactivation was noticed. For all the cobalt catalysts tested, the conversion vs. temperature plot was well described by a first order reaction, and the data were therefore fitted to obtain the activation energy and pre-exponential factors. (C) 2012 Elsevier B.V. All rights reserved.