CATALYTIC PROPERTIES OF CARBON-SUPPORTED RUTHENIUM CATALYSTS FOR N-HEXANE CONVERSION

The effect of the support (graphite, activated carbon, silica and alum ina) has been investigated using the conversion of n-hexane as model r eaction. The catalysts were characterized by H-2 adsorption and transm ission electron microscopy. Also, the CO adsorption was studied by mic rocalorimetry. The higher initial heat of CO adsorption observed on ru thenium/graphite indicates an enhanced electron density of the rutheni um particles caused by electron transfer from the graphite. The cataly tic results show that ruthenium particles with an increased electron d ensity have a higher activity for the n-hexane conversion accompanied by a preference for hydrogenolysis reaction, with the hydrogenolysis p attern corresponding to a multiple fragmentation. The higher resistanc e of ruthenium/graphite catalysts to deactivation by carbonaceous depo sits was also observed. (C) 1998 Elsevier Science B.V. All rights rese rved.