Rod-like carbon nanostructures produced by the direct pyrolysis of α-cyclodextrin

Templateless Synthesis of Ultra‐Microporous 3D Graphitic Carbon from Cyclodextrins and Their Use as Selective Catalyst for Oxygen Activation

“…This weight loss indicates that besides oxygen and hydrogen, about 50% of the carbon atoms are also removed in the pyrolysis, probably mostly as CO 2 , since otherwise the remaining mass of the carbon residue should have been 44%. Similar thermogravimetric profiles as the one measured here have been previously determined …”

“…The diameter of the channel can be determined by applying the Bragg equation to this peak corresponding to a pore diameter of 0.74 for G α‐CD , while it increases in dimension for G β‐CD and G γ‐CD . Observation of this low‐angle diffraction peak is unique and it has not been previously observed for any of the graphitic carbon residues derived from polysaccharides . Another notable difference between G CD and the graphitic carbon residues derived from pyrolysis of polysaccharides was that in the case of natural polysaccharides constituted by polymeric fibrils, the graphitic residue can be efficiently exfoliated upon sonication, forming suspensions of defective graphenes in quite high yield .…”

“…According to these TEM images and the microporosity observed in gas adsorption, it is proposed that these channels are derived from the assembly of conical cyclodextrin capsules as tubes during the pyrolysis process, as depicted in Scheme . It has been previously observed that the conical shape of cyclodextrins favors their assembly as tubes under certain conditions in solution and it could be that the same type of arrangement occurs in the cyclodextrin crystals that should melt during the process for a certain period (estimated melting point of cyclodextrins between 260 and 300 °C) before occurrence of the profound chemical transformation leading to G CD . According to Scheme , the cyclodextrin melts and the high temperatures should allow molecular arrangement as microtubules that undergo fusion into channels in subsequent steps.…”

“…It was anticipated that, if formed, the pore dimensions of these materials would be correlated somehow with the dimensions of the α‐, β‐, and γ‐cyclodextrins used as precursor and this pore dimension can influence their catalytic activity. In one related precedent, formation of rod‐like graphitic carbon nanostructures (micrometer length tubes, 10–40 nm diameter) evolving from structureless carbon was reported by pyrolysis of α‐cyclodextrin at temperatures higher than 1000 °C . However, no attention was paid to the structure of the carbon nanorod precursor that appears at lower temperatures.…”

Electrochemical Properties of Silicon/C Composite with Porous Carbon Designed Using α-Cyclodextrin and Surfactant

“…Therefore, we focused on nanostructured carbon materials with high specific surface areas (³800 m 2 g ¹1 ) that have been prepared by the simple carbonization of A-cyclodextrin acquirable with various heating rates. 10 In addition, we clarified that the porous carbon prepared by carbonization of A-cyclodextrin improved the performance of electric double-layer capacitors. 11 Our first strategy to develop a simple synthesis process was to optimize the carbonization conditions of the clathrate compounds prepared from A-cyclodextrin and surfactants in order to obtain porous carbon having a high specific surface area.…”