State of the Active Component and Catalytic Properties of Pd/C Catalysts on the Selective Hydrogenation of Butadiene-1,3 into Butylenes
V.V. Chesnokov, I.P. Prosvirin, V.I. Zaikovskii and N.A.Zaitseva
Boreskov Institute of Catalysis, Prosp. Akad. Boreskova, 5, 630090 Novosibirsk, Russia
Palladium (0.25-5.8 wt.%) was supported on three different types of filamentous carbon in which the basal graphite planes are arranged along, crosswise and at a 45° angle to the axis of a nanofiber. HREM, XPS and X-ray techniques were used to study the state of high dispersed Pd particles supported on the filamentous carbon. It was established that the type of the carbon support affects the properties of the active component. The high disperse Pd particles most strongly interact with the prismatic planes of graphite to provide electron transfer from palladium to the support, which stabilizes palladium in a more dispersed state. Because of this strong interaction, Pd2+ is stabilized in the ionic state. A change in the properties of the palladium particles initiates changes in the catalytic properties of Pd/C catalysts in the reaction of selective hydrogenation of 1,3-butadiene into butylenes. An increase in the fraction of Pd2+ in the catalyst composition results in the decrease of both total activity and selectivity of Pd/C catalysts in the considered reaction.