Ueber die Verbindungen des Kohlenstoffes mit Silicium, Eisen und andern Metallen, welche die verschiedenen Arten von Gusseisen, Stahl und Schmiedeeisen bilden

Abstract

S c h a f h l u t l , iiber ICohlenstoffeisen. 't59 se!bst jefzt, im April 1539, vollkomlsen an Gestalt und fast so hart sind, ala sic beim Hineinlegen waren, woriiber man wirlilich sich wundern muss.. Airs tiiesen Versuchen erhellt , dass kohlensmores Nntron zwei Artcn VOII Zerselnung verhinctert , denen die thieriscben und vegefnhilischen Sithsfanncn unlerwnrfen sind j crsllich diese Art dcr Zersefnung , nelche von Schimmelersr,eugun& bcgleitet , ist, ur?d xweilens dic Ai t, welche noch weiter geht untl in einer v6lligeri 'Aullijsung fer Theilchen. hesteht. Ob diese beiden Arten nur Griide von einanrler oder wesentlich verschiedea sind,-das kiimmert uns jetnt nicht ; es reicht zu anserm Zwecke hin, dass die mit der Schim~nelerzeugung verbundene Zersetzung gnns analog der ist, welche von Schwammerneopng oder dem Paulen (dem Trockenmoder, \vie er zmar gewiihnlich genannt wirti, aber vielleicht unpassender Weise) desHolzes begleilet wird. Es 1st d&er ausserordentlich wnhrscheinlich, dmss kohlensaurcs Natrort, welches das eine verhindert, nuch das andere verhindcrf. Uiu aber diesen Punet mit Gewissheit zu entscheiden, wiirtle es niithig sciit, Versuche Jabre lnng in einer Sehwammgruhe, wie die zu Wonlwich , anzustellen. Die grosse Wahrscheiiiliclilicit, dnss Natron dns Vermiigen besitzt, dem Trockenmoder ZII miderslehen, muss seinen Werth erbiihen, wo e s blos als eiu der Entziindu~~g widerstehendes Mitetl angewendet w i d .

Exfoliation of graphene via wet chemical routes

“…5a). The mechanism for the electrochemical exfoliation process of graphite is as follows: (i) electrolysis of water at the electrode produces hydroxyl and oxygen radicals; (ii) the as-produced radicals initially oxidize the edge and/or grain boundaries of the graphite; (iii) oxidation at the edge and grain boundaries leads to the depolarization and the expansion of the graphite layers, thereby facilitating the intercalation of SO 4 2− anions within the graphitic layers along with water; and (iv) reduction of the intercalated SO 4 2− anions and self-oxidation of water produces gaseous species, such as SO 2 and O 2 , which exert a large force on the graphite layers and thereby separate weakly bonded graphite layers from one another (Fig. 5e).…”

“…The use of strong acids such as H 2 SO 4 and H 3 PO 4 severely compromises the quality of graphene because the cooperative oxidation of hydrogen ions (H + ) and sulfate ions (SO 4 2− ) will lead to the over-oxidation of graphene, although the oxidation of graphene during the electrochemical processes is less extensive than that during chemical oxidation approaches. One possible approach to avoid over-oxidation and thereby improve the quality of EG is to select electrolytes with neutral pH, such as aqueous inorganic salt electrolytes.…”

“…However, the excessive oxidation of the graphite surface results in thin graphene oxide (GO) sheets with severe defects. When a relatively high positive voltage (e.g., 10 V) was applied to the graphite electrode in dilute sulfuric acid, the exfoliation of graphite was realized by the violent releasing of gases via the electrochemical reduction of sulfate ions (SO 4 2− ) [99]. Compared to many other protonic acid aqueous electrolytes, such as hydrobromic acid (HBr), hydrochloric acid (HCl), perchloric acid (HClO 4 ) and nitric acid (HNO 3 ), the lower reduction potential (0.172 V) renders sulfuric acid (H 2 SO 4 ) an ideal electrolyte for the exfoliation of natural graphite flakes or highly oriented pyrolytic graphite (HOPG).…”

“…Over the past decade, graphene has emerged as an exciting new material with the potential to impact many areas of science and technology. In fact, the research in this field started in the 1840s, when the intercalation compounds of graphite were first reported [4]. However, the observation of graphitic carbon monolayers by scientists dates back to the 1960s, when SiC was heated to 2150 • C [5].…”

Transparent and Electrically Conductive Films from Chemically Derived Graphene

“…Moreover, he repeated that procedure four times until the acid became clear, possibly due to oxidative decomposition of graphite. With the description of these experiments he became a pioneer for modern chemistry on graphite, its intercalated compounds and finally exfoliated graphite (Schafhaeutl, 1840).…”