Oxygen reduction fuel cells

Jacob T. 2006a. The mechanism of forming H2O from H2 and O2 over a Pt catalyst via direct oxygen reduction. Fuel Cells 6 159-181. 

Srivastava R, Mani P, Hahn N, Strasser P (2007) Efficient oxygen reduction fuel cell electrocatalysis on voltammetrically dealloyed Pt-Cu-Co nanoparticles. Angew Chem Int Ed 46(47) 8988-8991... 

Serov A, Artyushkova K, Atanassov P (2014) Fe-N-C oxygen reduction fuel cell catalyst derived from caibendazim synthesis, stmcture, and reactivity. Adv Energy Mater 4 1301735... 

There is also scope for use of nanoparticulate Au-Pt catalysts in the fuel cells themselves [47]. Work at Brookhaven National Laboratory in New York has shown that platinum oxygen-reduction fuel cell electrocatalysts can be stabilized against dissolution under potential cycling regimes (a continuing problem in vehicle applications) by modifying Pt nanoparticles with gold clusters. 

Bittins-Cattaneo B, Wasmus S, Lopez-Mishima B, Vielstich W. 1993. Reduction of oxygen in an acidic methanol oxygen (air) fuel-cell— An onhne MS study. J Appl Electrochem 23 625 -630. 

Cobalt porphyrins and phthalocyanines were used as precursors for preparation of carbon supported cobalt catalysts that displayed high activity in reduction of oxygen in fuel cells [9-12], These samples were prepared by deposition of cobalt phtalocyanine on active carbon following by heat treatment at 650-700°C in an inert atmosphere providing formation of Co-N structure deposited on active carbon. 

Fournier, J., G. Lalande, R. Cote, D. Guay, and J.R Dodelet (1997). Activation of various Fe-based precursors on carbon black and graphite supports to obtain catalysts for the reduction of oxygen in fuel cells. J. Electmchem. Soc 144, 218-226. 

The concepts of an artificial heart can be looked at in terms of a fuel cell driving an electric motor-driven pump (32), This was a program supported by the NIH in the 1970 s. The concept (Fig. 7) was that the heart could be run on a fuel cell consisting of one glucose-based electrode for oxidative power, the other electrode being used for the reduction of oxygen. A fuel cell was implanted in a dog, and ran for... 

The anode reaction in fuel cells is either direct oxidation of hydrogen, or methanol or indirect oxidation via a reforming step for hydrocarbon fuels. The cathode reaction is oxygen reduction from air in most fuel cells. For hydrogen/oxygen (air) fuel cells, the overall reaction is... 

Besides chemical catalytic reduction of carbon dioxide with hydrogen, which is already possible in the laboratory, we are exploring a new approach to recycling carbon dioxide into methyl alcohol or related oxygenates via aqueous eleetrocatalytic reduction using what can be called a regenerative fuel cell system. The direct methanol fuel cell... 

The conventional electrochemical reduction of carbon dioxide tends to give formic acid as the major product, which can be obtained with a 90% current efficiency using, for example, indium, tin, or mercury cathodes. Being able to convert CO2 initially to formates or formaldehyde is in itself significant. In our direct oxidation liquid feed fuel cell, varied oxygenates such as formaldehyde, formic acid and methyl formate, dimethoxymethane, trimethoxymethane, trioxane, and dimethyl carbonate are all useful fuels. At the same time, they can also be readily reduced further to methyl alcohol by varied chemical or enzymatic processes. 

Alkaline Fuel Cell. The electrolyte ia the alkaline fuel cell is concentrated (85 wt %) KOH ia fuel cells that operate at high (- 250° C) temperature, or less concentrated (35—50 wt %) KOH for lower (<120° C) temperature operation. The electrolyte is retained ia a matrix of asbestos (qv) or other metal oxide, and a wide range of electrocatalysts can be used, eg, Ni, Ag, metal oxides, spiaels, and noble metals. Oxygen reduction kinetics are more rapid ia alkaline electrolytes than ia acid electrolytes, and the use of non-noble metal electrocatalysts ia AFCs is feasible. However, a significant disadvantage of AFCs is that alkaline electrolytes, ie, NaOH, KOH, do not reject CO2. Consequentiy, as of this writing, AFCs are restricted to specialized apphcations where C02-free H2 and O2 are utilized. 

The aluminum-air fuel cell is used as a reserve battery in remote locations. In this cell aluminum reacts with the oxygen in air in basic solution, (a) Write the oxidation and reduction half-reactions for this cell, (b) Calculate the standard cell potential. See Box 12.1. 

The first reported electroorganic synthesis of a sizeable amount of material at a modified electrode, in 1982, was the reduction of 1,2-dihaloalkanes at p-nitrostyrene coated platinum electrodes to give alkenes. The preparation of stilbene was conducted on a 20 pmol scale with reported turnover numbers approaching 1 x 10. The idea of mediated electrochemistry has more frequently been pursued for inorganic electrode reactions, notably the reduction of oxygen which is of eminent importance for fuel cell cathodes Almost 20 contributions on oxygen reduction at modified... 

A fuel cell consists of an ion-conducting membrane (electrolyte) and two porous catalyst layers (electrodes) in contact with the membrane on either side. The hydrogen oxidation reaction at the anode of the fuel cell yields electrons, which are transported through an external circuit to reach the cathode. At the cathode, electrons are consumed in the oxygen reduction reaction. The circuit is completed by permeation of ions through the membrane. 

Binary systems of ruthenium sulfide or selenide nanoparticles (RujcSy, RujcSey) are considered as the state-of-the-art ORR electrocatalysts in the class of non-Chevrel amorphous transition metal chalcogenides. Notably, in contrast to pyrite-type MS2 varieties (typically RUS2) utilized in industrial catalysis as effective cathodes for the molecular oxygen reduction in acid medium, these Ru-based cluster materials exhibit a fairly robust activity even in high methanol content environments of fuel cells. 

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