Formation of Carbide‐Derived Carbon on β‐Silicon Carbide Whiskers

Abstract

Carbon was synthesized on b-SiC whiskers by extraction of Si atoms from SiC. In this study, three different elevated temperature extraction methods were used to remove Si atoms from SiC: treatments in either Cl 2 or HCl and vacuum decomposition. In all chlorination experiments and vacuum treatment at 17001C, carbon preserved the original shape of SiC whiskers. At higher temperatures (20001C), vacuum decomposition led to a distortion in the shape of the whiskers. High-resolution transmission electron microscopy and Raman spectroscopy showed that the structure of carbide-derived carbon depends on the Si extraction method and the process parameters. Chlorination of SiC resulted in the formation of mostly amorphous nanoporous carbon. High-temperature treatment of SiC in HCl environment produced fullerene-like structures, while high-temperature vacuum decomposition resulted in the formation of graphite. Transmission electron microscopy studies of the carbon coating thickness produced in Cl 2 at various chlorination times revealed linear reaction kinetics at 7001C. Raman studies showed that the carbon structure became more ordered with increasing chlorination temperature. The results obtained demonstrate that by using the silicon extraction technique, one can precisely control the thickness and morphology of the carbon coating. II. Materials and Experimental ProcedureExperiments were performed on cubic silicon carbide (b-SiC) whiskers with an average diameter of 200 nm and an aspect ratio 509 J ournal

Review of nanostructured carbon materials for electrochemical capacitor applications: advantages and limitations of activated carbon, carbide‐derived carbon, zeolite‐templated carbon, carbon aerogels, carbon nanotubes, onion‐like carbon, and graphene

“…108,[110][111][112][113][114] For EDLC applications, CDC is generally produced by treatment of carbides in a chlorine gas. In the case of binary carbides a simplified reaction can be written as: MeC x + 0.5Cl 2 = MeCl y + xC, where Me could be Al, 115 B, [116][117][118][119] Ca, 120 Cr, 121 Mo, 122,123 Si, 13,114,[124][125][126][127][128] Ti, 114,[129][130][131][132] V, 133 W, 134 Zr, 111,135 or other carbide-forming metals. In addition, CDC with enhanced pore volume could be produced using ternary carbides, such as Ti 2 AlC, Ti 3 AlC 2 , and Ti 3 SiC 2.…”

Carbide-Derived Carbons: Effect of Pore Size on Hydrogen Uptake and Heat of Adsorption

“…In contrast to other CDC, SiCderived CDC remain amorphous up to 1200°C. [21] Changes in CDC microstructure are inherently connected to changes in pore structure. Amorphous structures formed at lower temperatures are clearly associated with uniform and relatively small pores, whereas graphitic ribbon network structures formed at higher synthesis temperatures are linked to less uniform and generally larger pores (compare Figs.…”

Fabrication of Silicon Carbide Micropillar Arrays from Polycarbosilanes

“…It was shown previously that extraction of metals from carbides by halogens or their compounds leads to the formation of free carbon with various structures called carbide‐derived carbon (CDC) 37,38 . For SiC and β‐SiC whiskers, it has been reported that the Si component is preferentially attacked and a carbon‐rich layer builds up in the reaction with chlorine‐ or fluorine‐containing gases at temperatures >600°C 39,40 . Thus, CDC‐coated micropatterned SiC, which might be loaded with heterogeneous catalyst, can be of considerable interest for lining of reactor systems in chemical engineering to increase the performance of heterogeneous catalytic reactions.…”