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Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. [1]
Graphene (/ ˈ ɡ r æ f iː n /) [1] is a carbon allotrope consisting of a single layer of atoms arranged in a honeycomb planar nanostructure. [2] [3] The name "graphene" is derived from "graphite" and the suffix -ene, indicating the presence of double bonds within the carbon structure.
A rapidly increasing list of graphene production techniques have been developed to enable graphene's use in commercial applications. [1]Isolated 2D crystals cannot be grown via chemical synthesis beyond small sizes even in principle, because the rapid growth of phonon density with increasing lateral size forces 2D crystallites to bend into the third dimension. [2]
The process, called "Graphair", is so effective that water samples from Sydney Harbor were safe to drink after being treated. Graphene film makes dirty water drinkable in a single step Skip to ...
The basic chemical reaction involved in the Hummers' method is the oxidation of graphite, introducing molecules of oxygen to the pure carbon graphene. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts.
Bilayer graphene displays the anomalous quantum Hall effect, a tunable band gap [3] and potential for excitonic condensation. [4] Bilayer graphene typically can be found either in twisted configurations where the two layers are rotated relative to each other or graphitic Bernal stacked configurations where half the atoms in one layer lie atop half the atoms in the other. [5]
The starting material is water-dispersed graphene oxide flakes. The aqueous dispersion is vacuum filtrated to produce free standing foils. The thickness of these foils is typically in the range of 0.1-50 micrometers. Depending on application the graphene oxide laminates are named either as papers or as membranes.
Graphene doped with various gaseous species (both acceptors and donors) can be returned to an undoped state by gentle heating in vacuum. [22] [24] Even for dopant concentrations in excess of 10 12 cm −2 carrier mobility exhibits no observable change. [24] Graphene doped with potassium in ultra-high vacuum at low temperature can reduce ...