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Abstract

Four carbonaceous materials: carbon black, activated carbon, fullerene black and graphite, were employed in the NO–carbon reaction in order to study its structure sensitivity. The carbon structures were characterized by TEM and XRD analysis. The results obtained indicate that the internal structure of the samples employed greatly affects the reactivity of the samples towards NO. The reaction of NO with graphite shows a higher reaction rate per unit surface area than the reaction with the three amorphous carbons. The differences in reactivity between graphite and the amorphous carbons point to the presence of two kinds of active sites attributed to defective carbon sites and the carbon sites at the basal planes, respectively. The relative concentration of the different active sites depends on the structure of carbonaceous materials. The results obtained strongly suggest that the reaction between NO and carbon is a structure sensitive gas–solid reaction.