Carbon highly ordered pyrolytic

ENHANCED SIGNAL-TO-BACKGROUND RATIO WITH A HIGHLY ORDERED PYROLYTIC CARBON FILM AS AN ELECTROCHEMICAL INTERFACE... 

Fig. 2. Raman spectra (T = 300 K) from various sp carbons using Ar-ion laser excitation (a) highly ordered pyrolytic graphite (HOPG), (b) boron-doped pyrolytic graphite (BHOPG), (c) carbon nanoparticles (dia. 20 nm) derived from the pyrolysis of benzene and graphitized at 2820°C, (d) as-synthesized carbon nanoparticles ( 850°C), (e) glassy carbon (after ref. [24]).

On highly ordered pyrolytic graphite, HOPG(OOOl) electrodes, no UPD has been detected owing to weak carbon-lead interactions [311]. Deposition occurs by three-dimensional island growth according to Volmer-Weber mechanism. Initial steps are controlled by progressive nucleation on active sites and hemispherical diffusion. 

Figure 10.2 Fe(CN) /4 voltammetry on glassy carbon (GC) fractured in solution, and on basal plane highly ordered pyrolytic graphite (HOPG). 1 mM K4Fe(CN)6 in 1 M KC1, scan rate = 0.2 V/s. AEp for fractured GC voltammogram = 64 mV, corresponding to k° > 0.1 cm/s, AEp for HOPG = 1005 mV, k° = 1 x 10 6 cm/s. Potential scale is relative to silver quasi-reference electrode.

Figure 1.14 Atomic force microscopic image of highly ordered pyrolytic graphite (HOPG). The graphene lattice is indicated by the white lines. The different shading of carbon atoms results from the different situation in the atomic layer underneath ( A. Schwarz).

What are the apparent atomic distances of carbon atoms in a well-defined crystalline material To visualize individual atoms, a group of scientists used a scanning tunneling microscope (STM) to test a crystalline material called highly ordered pyrolytic graphite (HOPG). An STM is an instrument used to perform surface atomic-scale imaging. 

Janda, P., Frank, O., Bastl, Z., Klementova, M., Tarabkova, H., Kavan, L. Nanobubble-assisted formation of carbon nanostmctures on basal plane highly ordered pyrolytic graphite exposed to aqueous media. Nanotechnology 21, 095707 (2010)... 

Electrochemical deposition has been used to deposit Pt and Pt-based nanoparticles on a wide variety of substrates, including glassy carbon [33], highly ordered pyrolytic graphite (HOPG) [34, 35], carbon black inside Nafion [36], carbon nanotubes [37], and PAN-based carbon fibers [38]. A number of papers also... 

This chapter addresses several issues dealing with the mechanism of SEI formation on inert substrates, lithium, carbonaceous materials and tin-based alloys. Attention is currently focused on the correlation between the composition and morphology of the solid-electrolyte interphase forming on the different planes of highly ordered pyrolytic graphite (HOPG) and different types of disordered carbon electrodes in lithium-ion cells. 

Figure 2.50. RMS of a series of carbons including (i) diamond, (ii) highly ordered pyrolytic graphite (HOPG), (iii) polycrystalline graphite, (iv) glassy carbon (GC), (v) diamond-like carbon (DLC), (vi) fullerene and (vii) nanotube (Kakihana and Osada, 2003).

Worldwide and extensive investment in the carbon lithium-ion battery (LIB) has resulted in a plethora of publications to make this application an intensely studied form of carbon. It is also unique in the sense that the range of carbon structures studied for their suitability in lithium-ion batteries stretches from the most ordered of graphites (highly ordered pyrolytic graphites (HOPG)) to isotropic carbons of high surface area with a minimum of stmctural order. Such studies are relevant here because this complete range of carbons can be used to illustrate clearly the various porosities which exist within carbons as well as mechanisms of activation of carbons. 

Bowling, R., Packard, R., and McCreery, R. 1989. Activation of highly ordered pyrolytic graphite for heterogeneous electron transfer Relationship between electtochemical performance and carbon microstructure. 7. Am. Chem. Soc. 111 1217-1223. 

Diazonium salts have been electrografted on a variety of substrates various forms of carbon such as highly ordered pyrolytic graphite graphene,glassy carbon plates,carbon fibers and nanofibers, carbon felts, carbon blacks,ordered mesoporous carbons, ° carbon nanotubes and/or diamond,silicon,AsGa" ° and InAs/GaAs... 

The other major electrochemical modification approach has been that in which aromatic diazonium salts in an electrolyte solution are reduced at a diamond electrode this leads to the formation of an aryl radical, which can then attach to the diamond surface [74], This work is based on a series of papers in which the same technique was applied to the surface modification of glassy carbon and highly ordered pyrolytic graphite (HOPG) [75-78]. This approach may also be quite fruitful for tbe covalent modification of diamond surfaces, if the attachment is as robust as it is on glassy carbon surfaces. 

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