Study of some factors affecting the Ru and Pt dispersions over high surface area graphite-supported catalysts

In a study of the preparation of carbon-supported Pt and Ru catalysts, three high surface area graphites with similar textural characteristics, but differing in surface chemistry, have been used as carriers. Four series of metallic catalysts (two based on Pt and two on Ru) have been prepared by using different metal precursors and preparation methods. The catalysts were characterized by temperature-programmed reduction, H-2 and CO chemisorption and microcalorimetry of CO chemisorption. The achieved metallic dispersions mainly depend on the reduction-decomposition treatments and on specific interactions between the metal particles and surface defects at the graphite. Microcalorimetry of CO adsorption evidences that the presence of oxygen surface groups diminishes the metal-support interaction. (C) 1998 Elsevier Science B.V. All rights reserved.