Electrocatalyst supports

Redox flow Positive electrode, negative electrode substrate, electrocatalyst support, current collector, bipolar separator... 

Hydrogen/NiOOH Electrode additive, electrocatalyst support... 

Specific Activity (SA) and Mass Activity (MA) of Pt Electrocatalysts Supported on Different Carbon Powders Characterized by Specific Surface Area (S) and Particle Size (d)... 

Figure 9.16 ORR activity of two mixed-metal monolayer electrocatalysts supported on Pd(l 11), expressed as the kinetic current density at 0.85 V as a function of the M Pt ratio in the Pd-supported Pt-M monolayer. (Reproduced with permission from Zhang et al. [2005b].)...

Attwood PA, McNicol BD, Short RT. 1980. Electrocatalytic oxidation of methanol in acid electrolyte—Preparation and characterization of noble-metal electrocatalysts supported on pretreated carbon-fiber papers. J Appl Electrochem 10 213-222. 

Pt (5 wt%) supported on platelet and ribbon graphite nanofibers exhibited similar activities to those observed by Pt (25 wt°/o) on carbon black [138], This phenomenon was attributed to the crystallographic orientations adopted by the catalyst particles dispersed on graphitic nanofiber structures [139]. Also, the electrocatalysts supported on CNFs were less susceptible to CO poisoning than Pt supported on carbon black. 

The porous electrodes used in PAFCs are described extensively in the patent literature (6) see also the review by Kordesch (5). These electrodes contain a mixture of the electrocatalyst supported on carbon black and a polymeric binder, usually PTFE (about 30 to 50 wt%). The PTFE binds the carbon black particles together to form an integral (but porous) structure, which is supported on a porous carbon paper substrate. The carbon paper serves as a structural support for the electrocatalyst layer, as well as the current collector. A typical carbon paper used in PAFCs has an... 

In fuel cells, carbon (or graphite) is an acceptable material of construction for electrode substrates, electrocatalyst support, bipolar electrode separators, current collectors, and cooling plates. 

There are many considerations that must be taken into account when choosing a particular carbon, or carbon structure, as an electrocatalyst support. In hot phosphoric acid at cathodic potentials, the carbon surface is capable of being oxidized to carbon dioxide. The degree of oxidation will depend on the pretreatment of the carbon (for instance, the degree of graphitization), on the carbon precursor, and the provenance. There are two important parameters that will govern the primary oxidation rate for any given carbon material in an electrochemical environment. These are electrode potential (the carbon corrosion is an electrochemical process and therefore will increase rapidly as the electrode potential is raised) and temperature. 

Finally, the understanding of the chemistry of carbon and its stability in hot phosphoric acid in relation to its use as electrocatalyst supports, has led to the use of highly graphitic carbons, where the fundamental electrochemistry now is well defined. 

In the present work, CO2 electrochemical reduction was examined on higji area metal electrocatalysts supported on activated carbon fibers (ACF), which contain slit-shaped pores with widths on the order of nanometers. Such electrocatalysts were used in the form of gas difiusion electrodes (GDE), which are used in the fuel-cell field. The structure of this type of electrode is shown in Figure 1. The reaction takes places at the gas phase / electrolyte (liquid phase) / electrode interface, the so-called three-phase boimdary. 

Electrocatalyst support The main functions of the carbon support are to (a) disperse the ultrafine electrocatalyst particles, (b) bind strongly with the... 

One factor that may be important, but not systematically investigated, is the influence of the Pt electrocatalyst-support interactions on the electrocatalytic activity for O2 reduction. In Figure 14, an attempt to incorporate the pHzpc as a qualitative measure of the importance of carbon surface chemistry and metal-support interaction on the electrocatalytic activity of Pt is reported. The trend of the data in Figure 14 suggests that the specific activity for oxygen reduction increases as the pHzpc of the surface becomes more basic this effect may be related to the parallel increase of the particle size with the pHzpc of the catalyst. At this stage, one... 

Carmo M, Roepke T, Roth C, dos Santos AM, Poco JGR, Linardi M (2009) A novel electrocatalyst support with proton conductive properties for polymer electrolyte membrane fuel cell applications. J Power Sources 191 330-337... 

M. nieva, V. Tsakova, and W. Erfurth, Electrochemical formation of bi-metal (copper-palladium) electrocatalyst supported on poly-3,4-ethyelenedioxythiophene, Electrochim. Acta, 52, 816-824 (2006). 

Salgado IRC, Paganin VA, Gonzalez ER et al (2013) Characterization and performance evaluation of Pt-Ru electrocatalysts supported on different carbon materials for direct methanol fuel cells, hit J Hydrogen Energy 38 910-920... 

Bambagioni V, Bianchini C, Marchionni A, Filippi J, Vizza F, Teddy J, Serp P, Zhiani M (2009) Pd and Pt-Ru anode electrocatalysts supported on multi-walled carbon nanotubes and their use in passive and active direct methanol alcohol fuel cells with an anion-exchange membrane (alcohol = methanol, ethanol, glycerol). J Power Sources 190 241-251... 

Carbon constitutes the most abundant element of the different FC components. Setting aside the membrane, which is a polymer with a carbon backbone, all the other components, i.e. the CL, GDL and current collector plates (bipolar plates) are made almost entirely of graphitic carbon. The electrocatalyst support of the CL is commonly carbon black in the form of fine powder. GDLs are thin porous layers formed by carbon fibers interconnected as a web or fabric, while current collector plates are carbon monoliths with low bulk porosity. As explained above each of these components has a particular function within the fuel cell and in particular in the triple phase boundary. The structure and properties of the carbon in each of the different FC components will determine the whole performance of the cell. 

DMFC performance loss due to catalyst degradation has been attributed to several factors a decrement of the electrochemically active surface area (ECSA) of the platinum electrocatalyst supported on a high-surface-area carbon, a loss of cathode activity towards the ORR by surface oxide formation, and ruthenium crossover [83, 85, 116, 117]. 

Juttner, K., et al. 2001. Nano-scale conducting polymers as ion exchangers and electrocatalyst support. In Proceedings—Electrochemical Society, Volume 2001-23 (Energy and Electrochemical Processes for a Cleaner Environment), 428. 

Figure 3. SEM micrograph of the carbonized and pulverized PAA after Pd deposition. Inset SEM micrograph of PAA prepared in 0.3 M oxalic acid at 60 V. Reprinted from Zhenyou Wang, Fengping Hu and Pei Kang Shen, Carbonized porous anodic alumina as electrocatalyst support for alcohol oxidation, Electrochemistry Communications, 8 (2006) 1764-68, Copyright (2006) with permission from Elsevier.

Fang, B., Kim, J.H., Yu, J.S. Colloid-imprinted carbon with superb nanostructure as an efBcient cathode electrocatalyst support in proton exchange membrane fuel cell. Electrochem. Commun. 10(4), 659-662 (2008)... 

T., Chiu, C.-Y, Huang, X., and Huang, Y. (2012) Stabilization of high-performance oxygen reduction reaction Pt electrocatalyst supported on reduced graphene oxide/carbon black composite. /. Am. Chem. Soc., 134, 12326-12329. 

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