A multilayer replication method has been used to prepare reticulated ceramic foams from steel making wastes. These ceramic sponges have been used as support for preparing catalytic devices, after deposition of catalytic coatings of Al2O3, CeO2 and gold. The obtained catalytic systems are active to the CO oxidation reaction and may be stable with no loss of activity as far as the amount of residual water in the gaseous stream remains constant. In the absence of water and reaction temperatures of 150 degrees C the catalytic monolith shows 100% conversion of CO at least for 54 h. The metal content of the wastes has a positive influence in the activity of the foams. The best catalytic results are obtained for the Au/CeO2-supported foams where the oxidation capability of gold atoms is combined with the redox properties of the ceria phase. (c) 2006 Elsevier B.V. All rights reserved.