Electrocatalysts for the Direct Electrochemical Oxidation of n-Octane in Fuel Cells

Abstract

Equivalent weight of silver chloride cathode, g/equiv. Thickness of the layer of sponge silver, cm Thickness of the layer of sponge silver at the initiation of discharge, cm Anode efficiency; the ratio of the weight loss predicted by Faraday's law, to the observed anode weight loss, dimensionless 0Time, sec 0BTime at which the voltage effects of the MRVA begin, sec ~M Time at which the greatest voltage effects of the MRVA occur, sec ps Specific resistivity of the electrolyte-sponge silver matrix, ohm-cm ABSTRACT Until very recently, the direct oxidation of hydrocarbons in fuel cells required high loadings of platinum in the anodes, making such fuel cells prohibitively expensive. This paper describes some progress toward acceptably low loadings of high-activity platinum electrocatalysts for the direct anodic oxidation of liquid n-octane. The activity of both supported and unsupported platinum, prepared in various ways, has been compared to that of commercial platinum black. Investigations of carbon substrates of widely varying specific areas showed that an increase in the specific area of the substrate yields a corresponding increase in electrocatalyst activity, up to at least 200 m2/g. Certain preparations of platinum on a carbon support show activities of six to eighteen times that obtained from commercial platinum black. No current or voltage cycling has been encountered when 36 m/o hydrofluoric acid at 105~ has been used as the electrolyte, in contrast to the behavior with other acidic electrolytes.

Direct Anodic Oxidation of Methanol on Supported Platinum/Ruthenium Catalyst in Aqueous Cesium Carbonate

“…It should be reiterated that most work has been on hydrogen oxidation or oxygen reduction in acidic electrolytes. Some exceptions to this is the work by Watanabe on methanol in acids (mentioned above), and work by Cairns et al for methanol in carbonates [6] and long-chain saturated hydrocarbons (up to ten carbons per molecule) in HF electrolytes [23,24]. Again, there remains much work, which can be done on methanol oxidation with unique electrocatalyst and electrolyte combinations .…”

A Historical Perspective of Fuel Cell Technology in the 20th Century

“…In addition to inventing and developing the PEFC, this group of researchers examined the thermodynamics of fuel cells 22,23 and did a considerable amount of work on direct-hydrocarbon fuel cells, [24][25][26][27][28][29] as well as direct-ammonia fuel cells. 30,31 They also developed new electrode structures 32,33 and examined new electrocatalysts for use with reformate fuels.…”

“…In addition to developing the first fuel cell system to be used in a real application, the fuel cell research group at General Electric was also the first to publish a series of technical articles on fuel cells in the Journal. In addition to inventing and developing the PEFC, this group of researchers examined the thermodynamics of fuel cells 22,23 and did a considerable amount of work on direct-hydrocarbon fuel cells, [24][25][26][27][28][29] as well as direct-ammonia fuel cells. 30,31 They also developed new electrode structures 32,33 and examined new electrocatalysts for use with reformate fuels.…”

Compatibility Relationship among Reaction Equilibria, Equivalence Principle of Reaction Approaches, and Silicon Contamination in Semiconductors

“…In the studies of GaAs vapor-phase epitaxy using the Ga−AsCl 3 −H 2 system, Cairns and Fairman first observed a mole fraction effect: the carrier concentration in the epitaxial layer decreases with the increase of the mole fraction of AsCl 3 carried into the reaction tube by hydrogen. DoLorenzo and Moore, following Knight et al, performed a systematic study on it.…”