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Silver supported catalysts on alpha-alumina were prepared and characterized by Brunauer-Emmet-Teller equations, scanning electronic microscopy, X-ray diffraction and atomic force microscopy techniques. Results show that these are powerful techniques for the determination of texture, morphology and surface properties. It has been shown that the addition of Cs in the Ag/Al 2 O 3 catalyst increased the dispersion of silver with the formation of small silver particles over a thin silver film already formed over the alumina support. It is important to stress that atomic force microscopy measurements are significant to observe the film and the dispersion of Ag and, on the contrary, X-ray photoelectronic spectroscopy did not, however, it allows to the conclusion that undistinguishable silver, either as metallic or oxidation state, are present at the surface. X-ray diffraction results confirm predominantly metallic silver.

This work reports the behavior of fresh and deactivated monometallic (Pt, Pd) and bimetallic (Pd-Ce) alumina-based combustion promoters prepared in the laboratory. The different additives were tested in carbon monoxide oxidation reaction before and after hydrothermal deactivation. Among the tested samples the best activity in CO oxidation was obtained for the additive containing 660 ppm of palladium. The addition of 15% of cerium oxide to the palladium-based additive did not increase its performance.