Further insights into the Ru nanoparticles-carbon interactions and their role in the catalytic properties

Temperature-programmed reduction (TPR) and CO adsorption microcalorimetry along with the catalytic behaviour in the n-butane/H-2 test reaction were performed in order to determine the specific interactions of Ru nanoparticles supported on different carbon materials. Aspects such as the porous structure and surface chemistry (presence and elimination of surface oxygen functional groups) of the carbon material, or the effect of the metal precursor (e.g. presence of residual chlorine) on the final metal dispersion and on the surface structure of the Ru nanoparticles have been studied. The results obtained confirm that surface oxidation of the support along with the nature of the Ru precursor affects the distribution of the metal precursor over the support (and, consequently, the final ruthenium dispersion) and also the surface site distribution. Besides, elimination of the surface oxygen functional groups of the carbon material, during the reduction treatments of the fresh catalyst samples, leads to surface reconstructions on the Ru nanoparticles that seem to expose different crystallographic planes. The presence of residual chlorine leads to electron deficient Ru sites, and this modifies the CO chemisorption heats and affects the catalytic properties in the n-butane/hydrogen test. (C) 2005 Elsevier Ltd. All rights reserved.