II International Symposium on Carbon for Catalysis ABSTRACTS

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CARBON BASED STRUCTURED CATALYSTS FOR PROCESS
INTENSIFICATION: OPPORTUNITIES AND LIMITS
Kiwi-Minsker L.
Ecole Polytechnique Fédéral de Lausanne, Switzerland
e-mail: Lioubov.kiwi-minsker@epfl.ch
Intensification of heterogeneous catalytic processes involve besides of innovative
engineering of reactors, the proper design of the catalyst. Moreover, the new paradigm
requires the simultaneous development of the catalyst and the reactor. The catalyst design
should be closely integrated with the reactor design taking into consideration the reaction
mechanism, mass-/heat transfer and the energy supply addressing high selectivity/yield of the
target product.
Structured catalysts and reactors are powerful tools for process intensification. Examples
of this are structured reactors packed by honeycombs, foams, static mixers, gauzes,
membranes, fiber arrays and cloths. They present multiple advantages as compared to
conventional packed-bed reactors, like the higher ratio of surface/volume (up to 5-10 times),
much higher catalyst efficiency due to short diffusion paths for the reactants, and a very low
pressure drop during the flow passage (gas, or gas-liquid), through the catalytic bed.
Carbon materials (e.g. soot, charcoal, graphite …) are used since prehistoric time.
Activated carbon is one of the most widely used adsorbents and catalytic support. Since the
1960s various novel carbon materials have been developed. Carbon fibers derived from
polyacrylonitrile (PAN), pyrolytic carbons produced by chemical vapor deposition of
hydrocarbons and active carbon fibers were introduced to the market. These materials have
structures and textures that differ from the conventional carbon materials and have
demonstrated already advantages when used as adsorbents and catalysts. More recently,
fullerenes and carbon nanotubes were discovered opening completely different perspectives
and undergoing a rapid development.
Some aspects of the design of novel carbon based catalysts and of the structure control
over multiple scales will be discussed:
• Nano: for active sites and their environment;
• Micro: for spatial distribution of active sites and surface micro-composition;
• Meso: for pore structure and surface morphology;
• Macro: for catalyst form and geometry.
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