Room temperature oxidation of carbon monoxide over copper oxide catalyst

Carbon monoxide oxidation has been studied over different oxides of copper as well as a copper oxide sample obtained from precipitation. Room temperature oxidation of carbon monoxide to carbon dioxide has been achieved for the first time over unsupported copper oxide catalyst prepared by a controlled heating of precipitated copper hydroxide after activation of the catalyst in a redox environment. It is found that drying and calcination of the precipitated hydroxide are crucial parameters that affect the catalyst performance dramatically. Experimental results indicate that the active phase is a metastable non-stoichiometric form of copper oxide formed during the treatment of the oxide in a redox environment. This species loses its activity upon exposure to the outside atmosphere due to absorption of moisture. Nevertheless, the activity can be regained by an activation step.