TUNING POROSITY, STACKING DENSITY AND MECHANICAL STRENGTH OF CARBON NANOFIBER CATALYST SUPPORT MATERIAL

Two important pre-requisites have to be fulfilled for a good catalyst support material: a high bulk density and a high porosity. High support densities result in a more efficient use of the reactor volume and are therefore economically favorable above low density supports. On the other hand, the porosity i.e., accessibility is important in order to avoid mass transport limitations. Nowadays, new support materials, such as carbon nanofibers (CNF) are available. The properties of CNF potentially surpass those of conventional oxidic supports like a.o., silica and alumina [1,2]. Carbon nanofibers are chemically inert, pure and mechanically strong and thus suitable as catalytic support material. The CNF-bodies consist of entangled individual carbon nanofibers, which are formed during the catalytic growth via decomposition of CO and H2 on Ni/SiO2 growth catalysts. In this contribution, we show that for CNF supports both macroscopic structural properties, i.e, stacking density and porosity can be tuned. The metal loading of the growth catalyst and the growth time of the CNF-bodies are key factors in that respect.