Gold catalysts, supported electrode

The role of the crystalline surface structure, and in particular long range surface order, of platinum electrodes in the electrooxidation of D-glucose in acidic media has been discussed. Papers have been published on the effects of adsorbed anions on the oxidation of D-glucose on gold single crystal electrodes, and on the oxidation of D-sorbose and 2,3 4,6-di-0-isopropylidene-a-L-sorbose by air over supported platinum and palladium catalysts. ... 

The electrocatalytic activity of the nanostructured Au and AuPt catalysts for MOR reaction is also investigated. The CV curve of Au/C catalysts for methanol oxidation (0.5 M) in alkaline electrolyte (0.5 M KOH) showed an increase in the anodic current at 0.30 V which indicating the oxidation of methanol by the Au catalyst. In terms of peak potentials, the catalytic activity is comparable with those observed for Au nanoparticles directly assembled on GC electrode after electrochemical activation.We note however that measurement of the carbon-supported gold nanoparticle catalyst did not reveal any significant electrocatalytic activity for MOR in acidic electrolyte. The... 

Alkaline Fuel Cell The electrolyte for NASA s space shuttle orbiter fuel cell is 35 percent potassium hydroxide. The cell operates between 353 and 363 K (176 and 194°F) at 0.4 MPa (59 psia) on hydrogen and oxygen. The electrodes contain platinum-palladium and platinum-gold alloy powder catalysts bonded with polytetrafluoro-ethylene (PTFE) latex and supported on gold-plated nickel screens for current collection and gas distribution. A variety of materials, including asbestos and potassium titanate, are used to form a micro-porous separator that retains the electrolyte between the electrodes. The cell structural materials, bipolar plates, and external housing are usually nickel, plated to resist corrosion. The complete orbiter fuel cell power plant is shown in Fig. 27-62. 

The University of Illinios (Yeom et al.) demonstrated the fabrication of a monolithic Si-based micro-scale MEA consisting of two Si electrodes, with catalyst deposited directly on them, supporting a Nafion - 12 membrane in-between [12]. The electrodes are identically gold-covered for current collecting, and are covered with electrodeposited Pt black. The electrodes and the Nafion membrane are sandwiched and hot-pressed to form the MEA. The complete fuel cells have been tested with various fuels H2, methanol and formic acid and reached 35 mW cm , 0.38 mW cm and 17 mW cm , respectively, at RT with forced Oj. More recently, performances with formic acid as fuel were increased up to 28 mW cm" with electrodeposited Pd-containing catalyst at the anode [13]. 

The electrocatalytic activity of ORR on chalcogenides has been performed under hydrodynamic and temperature conditions using the rotating disk electrode (RDE) technique. We recall that dispersed catalysts either as non-supported or as supported on carbon have been prior prepared in form of inks, which are ahqnoted onto a well geometrically defined substrate, such as glassy caibon and/or gold disks. ... 

All report studies of methanol oxidation at polypyrrole supported catalysts have involved the use of electrochemically prepared films of the polymer on a solid electrode. Strike et al. (20), who electrochemically deposited Pt onto such electrodes from a H2PtCl5 solution, reported current densities for methanol oxidation that were enhanced by factors of 10-100 over those at bulk Pt and platinized gold electrodes. Furthermore, a less rapid decay of the current with time... 

Vogel et al. [61] studied the electrochemical oxidation of hydrogen on carbon-supported Pt electrodes in acidic electrolyte. The electrodes were made by pressing the catalyst with a minimum amount of PTFE into a small gold disk. 

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