Recommendations for the Production of Silicon Carbide‐derived Carbon Based on Intrinsic Kinetic Data

Abstract

Recommendations for mode of operation and critical dimensions regarding inner mass transfer limitation were deduced for the technical extraction of silicon from silicon carbide to produce nanoporous carbon (carbide-derived carbon, CDC). The recommendations are based on intrinsic kinetics derived from experimental data and reaction engineering simulation of the transient process (shrinking-core like mechanism). As the reaction takes place at 1000°C under chlorine atmosphere, kinetic data as well as diffusion coefficients are extracted from integral conversion data in a lab scale reactor. The reaction rate dependency for varying chlorine concentrations is represented best by a Hougen-Watson type rate approach with dissociative adsorption of a reactant. From the experimental data the effective diffusion coefficient of chlorine in the resulting nanoporous carbon could also be derived to 4 · 10 -8 m 2 s -1 at 1000°C.

Synthesis of carbon core–shell pore structures and their performance as supercapacitors

“…Briefly, CDC can be produced by reactive extraction of metals from carbides using chlorine gas at high temperatures, with the precursor and synthesis temperature governing the resulting porosity and degree of graphitization [16][17][18][19][20]. This process is characterized by the temperature influence on the structure of the resulting CDC and the shrinking core reaction mechanism (SCM), hence, the conversion of the material from the outside towards the center during selective extraction [21,22].…”

Mesoporous and Graphitic Carbide-Derived Carbons as Selective and Stable Catalysts for the Dehydrogenation Reaction

“…Hereby, the initial shape of the precursor is typically preserved. The resulting CDC can either show the shape of a macroscopic powder or be prepared as monolith, , foam, coating, or fibers, , thus allowing the synthesis of easy to handle carbon materials. Furthermore, the applied extraction conditions and the choice of the carbide precursor allow one to tune the textural properties and carbon microstructure with high accuracy .…”