Carbide‐Derived Carbons – From Porous Networks to Nanotubes and Graphene

Abstract

from carbides has attracted special attention lately. [ 3,4 ] Carbide-derived carbons (CDCs) encompass a large group of carbons ranging from extremely disordered to highly ordered structures ( Figure 1 ). The carbon structure that results from removal of the metal or metalloid atom(s) from the carbide depends on the synthesis method (halogenation, hydrothermal treatment, vacuum decomposition, etc.), applied temperature, pressure, and choice of carbide precursor.The growing interest in this fi eld is refl ected by a rapidly increasing number of publications and patents. A signifi cant progress in CDC research has been seen in several fi elds. Various carbide precursors have been systematically studied. Studies on binary carbides with different grain sizes show the possibility of low-temperature carbon formation for nanopowders. Also, a better understanding of graphene formation during high-temperature vacuum decomposition of silicon carbide has been achieved since SiC single crystals are now available in large sizes with extremely low defect concentrations and an almost atomically fl at surface fi nish. [ 8 ] CDC applications as electrode materials in electric double layer capacitors have attracted much attention lately. [ 9 ] The unique properties of porous CDC obtained by halogenation, such as a high specifi c surface area and tunable pore size with a narrow size distribution, make it an ideal material for sorbents or supercapacitor electrodes. CDCs have been derived from many precursors (SiC, TiC, Mo 2 C, VC, etc.) using a variety of treatment conditions that lead to a broad range of useful properties. Furthermore, graphene, [ 10 ] nanotubes, [ 11 ] and even nanodiamond [ 12 ] can be produced from carbide precursors. Their applications naturally differ from those of porous CDC.The last comprehensive journal review on this subject was published about fi fteen years ago in Russian; [ 13 ] book chapters published later [ 3,4 , 14 ] are less accessible and require updating due to rapid progress in the fi eld over the past few years. The most recent review of CDC [ 14 ] covers only energy-related applications. Therefore, a comprehensive review on the fi eld is long overdue. The goal of this article is to show how a variety of carbon structures can be produced from carbides, to explain how those structures can be controlled on the nanometer and subnanometer scale, and to describe CDC properties that are benefi cial for a number of applications. Carbide-Derived Carbons -From Porous Networks to Nanotubes and GrapheneCarbide-derived carbons (CDCs) are a large family of carbon materials derived from carbide precursors that are transformed into pure carbon via physical (e.g., thermal decomposition) or chemical (e.g., halogenation) processes. Structurally, CDC ranges from amorphous carbon to graphite, carbon nanotubes or graphene. For halogenated carbides, a high level of control over the resulting amorphous porous carbon structure is possible by changing the synthesis conditions and carbide precursor. The large number of...

Not just graphene: The wonderful world of carbon and related nanomaterials

“…However, when a natural precursor is used to make carbon, it is very diffi cult to control the structure and properties such as porosity. When a synthetic inorganic precursor, such as a carbide, is used, the number of carbon atoms per unit of volume of this crystalline structure is known exactly, and extracting the metal at elevated temperatures produces a carbon with well-controlled pore size by the following reactions: 18 SiC + 4H 2 O = C + Si(OH) 4 + 2H 2 (1) TiC + 2Cl 2 = C + TiCl 4 .…”

Local Relative Density Modulates Failure and Strength in Vertically Aligned Carbon Nanotubes

“…This microstructure, in turn, affects their mechanical behavior, in particular the modulus, buckling strength, and recoverability. Synthesis techniques for VACNTs can be divided into two main categories: the chemical vapor deposition (CVD) synthesis method where the VACNT film is coated onto an existing substrate, and the carbide-derived carbon (CDC) synthesis method, 1 where carbon is formed by selective extraction of the metal or metalloid atoms in the carbide (e.g., silicon carbide), transforming the carbide structure into pure carbon. Even within materials grown via CVD, control of the growth conditions, such as the atmosphere, catalyst activity, and pressure, are known to significantly affect the repeatability of the VACNT's morphology and hence the consistency of mechanical properties.…”

High selectivity of TiC-CDC for CO2/N2 separation

“…High-pressure analysis (in this work up to 1 MPa) were performed in a home-made fully automated equipment designed and constructed by the Advanced Materials group (LMA), now commercialized as iSorbHP 6 by Quantachrome Instruments. Before any experiment, samples were degassed (10 -8 MPa) at 150ºC for 4h.…”

“…The pore size in these materials is highly influenced by the carbide precursor and reactive extraction temperature. Higher temperatures during synthesis may allow restructuring of the carbon to a higher degree of graphitization and larger pores are formed [6,15,16]. At lower synthesis temperatures carbon molecular sieves can result, which could be of interest for the application of gas separation, e.g.…”

“…in the fields of electrochemistry, gas storage and catalysis [6][7][8][9][10][11][12][13][14]. The pore size in these materials is highly influenced by the carbide precursor and reactive extraction temperature.…”