Das Adsorptionsverhalten sehr dünner Kohlenstoff‐Folien

Abstract

Mit 3 Ahhildungen Yrqfessor H . W . Kohlsclziitter zuitz 60. Cebzwtstagc: gemxidnzet Iiilialt,sukcrsichl Sehr diinrie Kohlcnstoff-Folien wurden erhalten: 1. durch R,eduktion einer Suspension von Graphitoxyd (G. 0.) in vcrdiiiinter Natron-2. durch Verpuffung voii B. 0. beim Erhitzen. Die Adsorption yon Stickstoff, von Rlethyl~~lhlau und von Phenol mnrde gemessen; aulkrdem wurde die katalytische Leistung bei dcr HBr-Synthese bcstimmt. Bei dem durch R e d u k t ' i o n erhalterien Praparat wurden mit der Adsorpt,ion aus w d 3riger Losung groI3ere spez. Oberfllchen gefunden, als mit der Gasa,dsorption oder aus der katalytischen Leistung. Die gronte spez. Oberflache 3 urde direkt in der bei der R,eduktion erhaltcncn Suspension gcmcssen. Die niederen Werte der spez. Oberflaclie sind eiiie Folge cler Agglomeration bei dcr lsolierung. l m Gegensatz dazu gaben bei dem durch V e r p u f f e n erhaltenen Praparat alle Mcthoden gleiche spez. Oherflachen. Dieser Unt,erschied wird dnrauf zuriickgefuhrt, daR die Folien dcs durch Verpuffen von G. 0. erhaltenen Praparates im Gegensatz zii denen des Iicduktionsproduktes durchliichcrt sind. Die Messung der kahlyt'ischen Leistung ergab, daB die Brornu.a,sserstoff-BilcluIig an den Bnsisflachen des Kohlenstoffs erfolgt. huge, SummaryExtremely thin carbon foils were obtained: 1. by reduction of gra.phite oxide (G. 0.) suspended in dilute sodium hydroxide, 2. by deflcgration of heated G. 0. The adsorption of nitrogen, methylcne blue arid phenol were mcasured its well a.s the cata1yt)ic efficiency in the HTh synthesis.Wit,h the samples obtained by reduction of G. O., la.rger surface areas were found by adsorption from solution tha,n by nit,rogen adsorption or from the cat'alytic cfficiency. This is explained by the agglomeration of the foils on isolation.With the deflagration product, however, a11 methods gave the same surface arexs. The ca use of this different adsorption behaviour is discussed.

Functionalized Graphenes and Thermoplastic Nanocomposites Based upon Expanded Graphite Oxide

“…Several groups have pioneered this approach. [29,30,20,21] The groups of Aksay and Prud'-homme have investigated the formation of functionalized graphenes and nanocomposites based upon expanded graphite oxide. [20,21] Chemical reduction employs reducing agents such as hydrazine, Vitamin C and others.…”

“…Taking into account the specific graphene surface area of around 2 600 m 2 Á g À1 , the degree of exfoliation can be estimated to be around 50%. [30] In this thermal reduction process the decomposition of functional groups such as the epoxygroup can account for structural defects impairing planarity of the functional graphene sheets. [20] However, this reduction process is thermodynamically favored because of partial recovery of the polycyclic aromatic ring system.…”

Structural Breathing of Graphite Oxide Pressurized in Basic and Acidic Solutions.

“…Graphite oxide can be easily dispersed as separate layers in water solution, deposited as thin films 10,[21][22] and converted into graphene by mild heat treatment, by reduction in solutions (see e.g. 6,9,[23][24] ) or even by light from a camera flash 25 . Several structural models have been proposed for GO based on NMR, XPS and IR spectroscopy data 4-,8,13,15,26-27 , and some of them suggest that epoxy, carbonyl and -OH groups X-rays are attached to the graphene skeleton which results in some buckling of the planes.…”

Synthesis of graphene

“…Besides, a great deal of effort is required to develop techniques for modifying and opening its band structure so as to make it a potential replacement for silicon in future electronics. Graphene has been experimentally studied for over 40 years [8][9][10][11][12][13][14] and measurements of transport properties in micromechanically exfoliated layers [15], of graphene grown on (SiC) [16], large-area graphene grown on copper (Cu) substrates [17], as well as a variety of studies involving the use of chemically modified graphene (CMG) to make new materials [12][13][14][15][16][17][18][19][20][21].…”