Use and observation of the hydrotalcite "memory effect" for VOC oxidation

Cobalt supported on calcined hydrotalcite catalysts were prepared using the memory effect of Mg-Al hydrotalcite. Mg-Al was calcined at different temperatures from 500 to 900 °C and dipped in a Co nitrate aqueous solution for surface hydrotalcite regeneration. The calcination at 500 °C of the sample Co/Mg-Al(700) leads to an interesting Co mixed oxide supported on calcined hydrotalcite with high specific area and highly active and selective for toluene oxidation. The surface Co hydrotalcite regeneration was observed especially by Infrared Spectroscopy and Scanning Electron Microscopy combined with Energy Dispersive detection of emitted X-ray photons. The reconstruction of the layered structure influences positively the iteraction between cobalt species and the support.