Carbon high surface area

Chaffee, A.L., Loch, H.J. and Pandolfo, A.G., "Methane Adsorption on High Surface Area Carbons" CSIRO, Division of Fuel Technology, Investigation Report FT/IR 03IR (1989)... 

In redox flow batteries such as Zn/Cl2 and Zn/Br2, carbon plays a major role in the positive electrode where reactions involving Cl2 and Br2 occur. In these types of batteries, graphite is used as the bipolar separator, and a thin layer of high-surface-area carbon serves as an electrocatalyst. Two potential problems with carbon in redox flow batteries are (i) slow oxidation of carbon and (ii) intercalation of halogen molecules, particularly Br2 in graphite electrodes. The reversible redox potentials for the Cl2 and Br2 reactions [Eq. (8) and... 

In their earlier work, Modes et al. [53] described low polarization electrodes composed of Teflon-bonded high surface area carbon, loaded with different electrocatalysts (Pt, platinized Pt, Co, Ni). The best results were obtained by using cobalt... 

High surface area carbon (CSX-203 desulfurized) was Impregnated with Fe3(C0)i2 and subsequently reduced at 723 K for 16 h In flowing H2 (30 cc/mln). The magnetic and Mossbauer characterization was carried out on the decarbonylated (fresh) and reduced products. 

Figure 8. Mossbauer spectrum of 7% w/w FePc dispersed on a high surface area carbon (XC-72). The specimen was prepared In the same fashion as described In the caption Fig. 6. The spectrum corresponds to the dry material (19).

These conclusions from the infrared reflectance spectra recorded with Pt and Pt-Ru bulk alloys were confirmed in electrocatalysis studies on small bimetallic particles dispersed on high surface area carbon powders.Concerning the structure of bimetallic Pt-Ru particles, in situ Extended X-Ray Absorption Fine Structure (EXAFS>XANES experiments showed that the particle is a true alloy. For practical application, it is very important to determine the optimum composition of the R-Ru alloys. Even if there are still some discrepancies, several recent studies have concluded that an optimum composition about 15 to 20 at.% in ruthenium gives the best results for the oxidation of methanol. This composition is different from that for the oxidation of dissolved CO (about 50 at.% Ru), confirming a different spatial distribution of the adsorbed species. 

Activated carbons. Activated carbons are high-surface-area carbons. They are extensively used in industry, mainly as adsorbent. They are also used as a carrier material in catalysis because of their rather unique properties ... 

Baranton S, Coutanceau C, Roux C, Hahn F, Leger JM. 2005. Oxygen reduction reaction in acid medium at iron phthalocyanine dispersed on high surface area carbon substrate tolerance to methanol, stability and kinetics. J Electroanal Chem 577 223-234. 

A classic definition of electrochemical ultracapacitors or supercapacitors summarizes them as devices, which store electrical energy via charge in the electrical double layer, mainly by electrostatic forces, without phase transformation in the electrode materials. Most commercially available capacitors consist of two high surface area carbon electrodes with graphitic or soot-like material as electrical conductivity enhancement additives. Chapter 1 of this volume contains seven papers with overview presentations, and development reports, as related to new carbon materials for this emerging segment of the energy market. 

The use of carbon-based catalysts offers certain advantages over metal catalysts due to their availability, durability, and low cost. In contrast to the metal-based catalysts, carbon catalysts are sulfur resistant and can withstand much higher temperatures. Muradov [98,99] screened a variety of carbon materials and demonstrated that the efficient catalytic methane decomposition can be accomplished over high surface area carbons at temperatures... 

Carbon comes in many forms and surfaces areas. Graphite can have surface area below 1 m2/g, while high surface area carbon blacks approach 2000 m2/g. If Pt adsorbs onto carbon at the same surface density, the Pt loading (Pt, wt%) will then be a function of the carbon surface area. Assuming that CPA can be adsorbed onto carbon at 1.6 mmol/m2, and PTA at 0.84 mmol/m2 at the respective SEA conditions, plot Pt (wt%) vs. surface area of carbon. 

A PEFC consists of two electrodes in contact with an electrolyte membrane (Fig. 14.7). The membrane is designed as an electronic insulator material separating the reactants (H2 and 02/air) and allowing only the transport of protons towards the electrodes. The electrodes are constituted of a porous gas diffusion layer (GDL) and a catalyst (usually platinum supported on high surface area carbon) containing active layer. This assembly is sandwiched between two electrically conducting bipolar plates within which gas distribution channels are integrated [96]. 

Fig. 14.16 ECA evolution (inset normalized ECA) for Pt supported on nitrogen-doped MC (square) and Pt supported on high surface area carbon black (circle). Operating conditions voltage cycling between 0.5 to 1.0 V vs. RHE, 50 mVs"1 scan rate, room temperature, 0.1 M HC104 (Reprinted with permission from [151] - 2012 Wiley).

Electrochemical capacitors have been studied for many years. The first patents date back to 1957, where a capacitor based on high surface area carbon was described by Becker. Later in 1969 first attempts to market such devices were undertaken by Standard Oil Company of Ohio (SOHIO). However, only in the 1990s did electrochemical capacitors become famous in the context of hybrid electric vehicles. The electrochemical capacitor (EC) was supposed to boost the battery or the fuel cell in the hybrid electric vehicle to provide the necessaiy power for acceleration, and additionally allow for recuperation of brake energy (Viswanathan, 2006). 

As described above, XAS measurements can provide a wealth of information regarding the local structure and electronic state of the dispersed metal particles that form the active sites in low temperature fuel cell catalysts. The catalysts most widely studied using XAS have been Pt nanoparticles supported on high surface area carbon powders,2 -27,29,so,32,33,38-52 represented as Pt/C. The XAS literature related to Pt/C has been reviewed previ-ously. In this section of the review presented here, the Pt/C system will be used to illustrate the use of XAS in characterizing fuel cell catalysts. 

Potentials vs SHE. High-surface-area carbon supports in 02-saturated buffer. Catalyzed by bilirubin oxidase in the presence of chloride. Catalyzed by fungal laccase, chloride absent. Moderate stirring by bubbled gas. Strong stirring by rotating disk electrode at 4 krpm. 

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