Graphite surface adsorption

FIG. 1 Schematic picture of the graphite surface (C atoms occupy the corners, periodic boundary conditions apply in v and v directions) the adsorption sites in the y/3 X y/3 structure are shaded. 

The simplest example of oxygen spillover is found in the adsorption of oxygen on carbon. The spillover oxygen migrates from the basal carbon (donor) to carbon atoms exposed at steps between layers of the graphite surface, where it reacts with the edge carbons (acceptor).71 In this case the donor and acceptor phase consist of the same material with different surface properties. 

In 1975, the fabrication of a chiral electrode by permanent attachment of amino acid residues to pendant groups on a graphite surface was reported At the same time, stimulated by the development of bonded phases on silica and aluminia surfaces the first example of derivatized metal surfaces for use as chemically modified electrodes was presented. A silanization technique was used for covalently binding redox species to hydroxy groups of SnOj or Pt surfaces. Before that time, some successful attemps to create electrode surfaces with deliberate chemical properties made use of specific adsorption techniques... 

It is known that some spinel-structured 3d-metal oxides are good catalysts for many processes involving electron transfer [12]. However, their low conductivity does not allow for the direct use in the electrode of the battery, and grafting them onto the carbon matrix is also very difficult technical problem. It was found recently that this problem could be solved indirectly, creating the spinel catalytic centers on the surface of carbon by means of adsorption of some 3d-metal complexes on the graphite surface followed by subsequent pyrolysis at certain temperatures [13,14],... 

CV of graphite (from pencil) electrode modified by surface adsorption of pfiosphomoiyWic acid in 0.5 M sulfuric add... 

Recently, in the theoretical studies on the simulation for N2 adsorption in micropore, some researchers102-104 reported that the monolayer adsorption occurs even in the micropore whose pore width is greater than the bilayer thickness of N2 (about 0.7 nm). In addition, Kaneko et al. showed the presence of the orientational phase transition of N2 on the graphitic micropore wall, which is the same as the phase transition of the monolayer on the flat graphite surface,105 and gave an effective method for the surface area determination in the microporous system.106 Therefore, even for micropores whose width is greater than 0.7 nm, dV MS can be... 

Loeser and Harkins (45) have made a critical comparison of the Brunauer-Emmett-Teller and Harkins-Jura methods of calculating the surface area of graphite by adsorption of n-heptane at 25° C. The lower limit of surface area which can be measured by the Harkins-Jura method using n-heptane is given as 2500 sq. cm. 

All measurements of this work were carried out using the ratio between guanine signal of the target and non-complementary sequences to control the non-specific adsorption of oligonucleotide sequences onto the graphite surface. 

Kowalczyk P, Tanaka H, Kaneko K, Terzyk AP, and Do DD. Grand canonical Monte Carlo simulation study of methane adsorption at an open graphite surface and in slit like carbon pores at 273 K. Langmuir, 2005 21(12) 5639-5646. 

Most of the calculations support the use of the surface molecule concept. The features predicted for metals such as Ni and Pb and nonmetals such as C are in accord with what is expected from experimental measurements. One exception is the graphite surface where different adsorption properties were found, depending on whether a finite or infinite surface model was employed. 

XIV. The Nature of the Adsorptive Forces between the Inert Gases and a Graphite Surface... 

Hhere z is the distance from the graphite surface, A is the distance between the Kraphite layers (0.335 nm) and p is the number of carbon atoms per unit volume m4nm 3). The derivation of this 10-4-3 potential function involved integration ver the basal plane and summation over the successive layers. The 10- and 54- terms, therefore, represent the repulsive and attractive interactions with the psal plane, while the 3- term takes care of the summation over the remaining layers. This form of potential function has been favoured in recent computer Ifoulation studies of the adsorption of molecules by porous carbons (Nicholson, 996,1997). 

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