Co3O4 hollow nanotubes for the catalytic oxidation of C2-chlorinated VOCs
Amaya Gil-Barbarin, Jose Ignacio Gutiérrez-Ortiz, Rubén López‐Fonseca, Beatriz de Rivas
Abstract
Structured Co 3 O 4 catalysts with a hollow nanotube morphology were prepared by several synthesis routes based on the Kirkendall effect. The resulting samples were kinetically evaluated in the gas-phase oxidation of vinyl chloride and 1,2-dichloroethane, two model C 2 -chlorinated volatile organic compounds; and exhaustively characterised by means of BET measurements, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, thermogravimetry and temperature-programmed techniques (adsorption of ammonia and chlorinated VOC, O 2 -TPD, H 2 -TPR and TPO). The performance of the prepared nanotubes was essentially controlled by the presence of active oxygen species at the surface, which in turn depended on the Co 2+ /Co 3+ molar ratio, and the adsorption capacity of the catalyst for the chlorocarbon. Both pollutants were efficiently converted to deep oxidation products at relatively low temperatures. In addition, the optimal catalyst exhibited an appreciable stability when operating during 120 h. • Various hollow Co 3 O 4 nanotubes were evaluated for Cl-VOC oxidation. • These nanostructures enhanced the mobility of oxygen species. • Low coordination defect lattice oxygen sites was favoured by presence of Co 2+ . • Cl-VOC adsorption capacity was essential for the efficient Cl-VOC oxidation. • A remarkable stability was found with prolonged time on stream (120 h).