Electrogenerative and related processes

Langer, Stanley H.; Card, John C.; Foral, Michael J.

doi:10.1351/pac198658060895

Cited by 26 publications

(15 citation statements)

References 16 publications

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“…T h e favorable thermodynamics and the kinetics afforded by catalytic electrodes are factors which enable the electrogenerative cell to operate so that nitric oxide reacts with simultaneous D.C. current generation. These and similar reactions, as well as cell construction, have been described in a number of places [5,10,11,[14][15][16].…”

Section: Electrogenerative Processesmentioning

confidence: 84%

Electrogenerative and related electrochemical methods for NO_x and SO_x control

et al. 1986

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Electrogenerative processes cun be used to reduce nitric oxide to low levels in a vuriety of gas stretiins. An upproach for upplying these und related electrochemical reduction processes to selectively reduce NO, concentrutions in power plant efluents is discussed. Both electrogenerutive oxidation and reduction of sulfur dioxide cun occur. However, oxidation of sulfur dioxide to sulfirric ucid seems to be the 7iu)st feusible route for incorporution into an electrochemicul Jue gas treatment which might ulso produce useful chemicals. A strutegy for implementing an "electroclzemical scrubbing" procedure is described.

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Section: Electrogenerative Processesmentioning

confidence: 84%

Electrogenerative and related electrochemical methods for NO_x and SO_x control

et al. 1986

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“…Here, we have demonstrated reductive pretreatments at high surface area electrodes which produce significantly enhanced oxidation currents that are steady for at least 40 rain at potentials of 450-700 inV. Sulfurmodified gas diffusion electrodes prepared for ethanol oxidation (7,9,10) retained their special selectivity properties with little change through 5 h of continuous operation. Longer term stability has not been investigated but is less critical with cells operating on an SO2 substrate, because the treatment described here can be periodically renewed in situ if needed.…”

Section: Discussionmentioning

confidence: 98%

Oxidation of Sulfur Dioxide in Sulfur‐Modified Platinum‐Graphite Packed Bed Electrodes

Lyke

Langer

1991

J. Electrochem. Soc.

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The oxidation of dissolved sulfur dioxide at platinum supported in porous graphite sheet electrodes was investigated between 450 and 750 mV (RHE) using a variety of platinum loadings and SO2 concentrations. Controlled reductive pretreatment of these porous electrodes in the presence of SO2 was found to produce catalytic effects which resulted in enhanced steady-state oxidation currents due to formation of a sulfur-modified platinum surface. In hybrid cells with fuel cell-type oxygen gas diffusion cathodes operating in the electrogenerative (galvanic) mode, the pretreated platinumgraphite anodes were used to oxidize 3-500 mM SO2 in 3M H2SO4. Performance of the anodes, which contained 0.3-18 mg Pt/cm 2, was shown to be consistent with kinetic control by a mechanism similar to those postulated from earlier studies of the reaction at bulk platinum. Pretreatment appears to enhance the rate of the electron transfer steps without affecting that of a preceding chemical step. The pretreatment effect is not limited to graphite-supported platinum electrodes and seems to be general for SO2 oxidation at high surface area platinum anodes.The electrochemical oxidation of sulfur dioxide is of practical interest because of potential applications such as waste gas clean-up with sulfuric acid recovery (1-4) and possible use in energy conversion cycles (5, 6). Work here is a continuation of earlier investigations into the electrogenerative anodic oxidation of sulfur dioxide and possibilities for improving performance. Recently, we described how the reduction of adsorbed sulfur dioxide at porous, platinum-black gas diffusion electrodes produced catalyst modifications which altered selectivity considerably both in the course of ethanol oxidation and of nitric oxide reduction (7-10). Similar electrodes were studied for anodic oxidation of gaseous SO2 (11, 12) but a quantitative effect of pretreatment was not identified.Anodic oxidation of dissolved sulfur dioxide at bulk precious metal electrodes has been the subject of several investigations into the effect of electrochemical pretreatments on voltammetric behavior (13)(14)(15)(16)(17)(18)(19)(20). Enhancement of anodic current (activation) was observed after certain pretreatments which involved controlled reduction in the presence of dissolved sulfur dioxide. Few of these studies investigated steady-state performance of activated electrodes (17-19) while earlier studies with high surface area electrodes (1, 2, 5, 21) did not address the effect of pretreatment on SO2 oxidation rate. Thus, it was of special interest to explore the effect of a reductive pretreatment on the steady-state operation of working cells converting SO~ to sulfuric acid with high surface area electrodes.An interesting, early description of pretreatment procedures and their effects on anodic oxidation of SO2 at bulk platinum is found in papers by Seo and Sawyer (13,22). Using 1-10 mM SO2 in 0.1M H2SO4, they found that cycling the electrode potential between -0.15 and +1.5 V vs. SCE resulted in enhanced and more re...

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“…Several reviews by Langer et al [1,2,32] have assessed a variety of potential organic synthesis reactions that can be carried out using electrogenerative processes. The details of reactions such as hydrogenation, dehydrogenation, halogenation and oxidation of alcohols have been discussed elsewhere [33 -38].…”

Section: Electrosynthesis Of Organic Chemicals By Electrogenerative Pmentioning

confidence: 99%

“…The fuel cell is an example of a galvanic reactor, but it generally emphasizes complete fuel combustion and maximum power generation, with little or no consideration given to recovering products [1]. Fuel cell-related electrogenerative cells are small electrochemical reactors that differ from fuel cells in that their main function is chemical processing and production and the electricity that is generated from a particular chemical process is considered a by-product [2].…”

Section: Introductionmentioning

confidence: 99%

“…Fuel cell-related electrogenerative cells are small electrochemical reactors that differ from fuel cells in that their main function is chemical processing and production and the electricity that is generated from a particular chemical process is considered a by-product [2]. Generally, electricity has a minor value compared to the desired chemicals [1]. All electrogenerative processes have a negative Gibb's free energy (DG a 0), which means that they are thermodynamically favorable and are spontaneous redox reactions.…”

Section: Introductionmentioning

confidence: 99%

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Electrogenerative Processes for Environmental Applications

Yap

Mohamed²

2008

CLEAN Soil Air Water

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The applications of electrogenerative processes which could be an alternative to current environmental treatment technologies are briefly reviewed. This process does not require an external supply of energy due to the spontaneous chemical reaction that takes place in the reactor and generates an external flow of current as a by-product. The operation is attractive in reducing operational costs, especially when dealing with solutions of low ion concentrations. Electrogenerative reactors which can be operated in various configurations and their designs are described. The rate and selectivity for particular reactions can be controlled by varying electrode potentials and with suitable choices of electrodes. This review paper aims to invoke the interest of industries to consider the merits of electrogenerative processes as a replacement for the current processes and practices. The applications of electrogenerative processes to the removal and recovery of metal ions, electrosynthesis of organic chemicals and leaching of sulfide minerals are discussed.

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Electrogenerative and related processes

Cited by 26 publications

References 16 publications

Electrogenerative and related electrochemical methods for NO_x and SO_x control

Electrogenerative and related electrochemical methods for NO_x and SO_x control

Oxidation of Sulfur Dioxide in Sulfur‐Modified Platinum‐Graphite Packed Bed Electrodes

Electrogenerative Processes for Environmental Applications

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Electrogenerative and related processes

Cited by 26 publications

References 16 publications

Electrogenerative and related electrochemical methods for NOx and SOx control

Electrogenerative and related electrochemical methods for NOx and SOx control

Oxidation of Sulfur Dioxide in Sulfur‐Modified Platinum‐Graphite Packed Bed Electrodes

Electrogenerative Processes for Environmental Applications

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Product

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Electrogenerative and related electrochemical methods for NO_x and SO_x control

Electrogenerative and related electrochemical methods for NO_x and SO_x control