Potential Oscillations during the Electrocatalytic Oxidation of Sulfide on a Microstructured Ti/Ta2O5-IrO2 Electrode

and, Aicheng Chen; Miller, B.

doi:10.1021/jp036639h

Cited by 64 publications

(59 citation statements)

References 39 publications

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“…Similar behaviour has been observed at platinum anodes [9]. The oscillations were explained in terms of deposits of elemental sulfur, which repeatedly formed on the anode surface and either flaked off [8] or was dissolved as polysulfide by the action of excess sulfide ion [10].…”

Section: Introductionmentioning

confidence: 66%

Electrochemical oxidation of sulfide ion at a boron-doped diamond anode

2006

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The goal of the present research was the direct conversion of sulfide, an important contaminant in geothermal brines, to sulfate, whose discharge limits are much less stringent than those for sulfide. By the use of a novel anode material boron-doped diamond (BDD), we achieved near-quantitative electrochemical conversion of sulfide ions to sulfate with current efficiency of 90%. Kinetically, the reaction is first order in current density and zero-order in sulfide concentration. The current efficiency becomes essentially quantitative in the presence of chloride ion; under these conditions the reaction is chloride-mediated, at least in part, through the electrochemical formation of hypochlorite ion. Control experiments showed that hypochlorite oxidizes sulfide to sulfate quantitatively under the same conditions.

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Section: Introductionmentioning

confidence: 66%

Electrochemical oxidation of sulfide ion at a boron-doped diamond anode

2006

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“…[5][6][7]12,[14][15][16][17][18]20,22,24,25,27,28,34,35,38,39,47,[49][50][51] We have been also investigating the coating structure, morphology, electrochemical behaviors, and durability of IrO 2 TaCl 5 into n-butanol. The precursor solution also contained 6 vol% HCl as an additive and total metal (Ir + Ta) concentration was 70 g dm ¹3 .…”

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confidence: 99%

Effects of Oxide Composition on Structure, Surface Morphology, and Oxygen Evolution Behaviors of IrO2-Ta2O5/Ti Anodes Prepared at a High Temperature

Kawaguchi

Morimitsu

2015

Electrochemistry

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Catalytic coatings comprising a mixture of IrO 2 and Ta 2 O 5 were prepared at 50-80 mol% Ir by thermal decomposition at 470°C, and the crystallographic structures and surface morphologies were investigated. XRD analysis and high-resolution SEM observation using low accelerated incident beam revealed that decreasing Ir ratio made a phase transition of IrO 2 from crystalline to partly amorphous, and nano IrO 2 particles of 10 nm or less and nano chains made of them, which were uniformly dispersed on the flat area of the coating, were generated at 50-60 mol% Ir. The relationship between nano-scale surface morphology of the coating and electrocatalysis for oxygen evolution in H 2 SO 4 solutions was also investigated. The active surface area and oxygen evolution current increased with reducing Ir ratio. The electrocatalysis of the IrO 2 -Ta 2 O 5 coatings for oxygen evolution is possible to be attributed to nano IrO 2 particles.

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“…Also other electrode types were involved for such studies. Recently, Chen and Miller [148,149] have reported galvanostatic potential oscillations in the electrocatalytic oxidation of S 2À ions on a microstructured Ti/Ta 2 O 5 -IrO 2 electrode. Two distinct galvanostatic potential oscillations (oscillations A and B) were identified.…”

Section: Oscillatory Oxidation Of Sulfur Compoundsmentioning

confidence: 99%

Temporal Instabilities in Anodic Oxidation of Small Molecules/Ions at Solid Electrodes

Orlik

2012

Monographs in Electrochemistry

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Oscillations and multistability in oxidation processes at solid electrodes are important for several reasons. First, they were reported for species that are (or can appear) important in chemical engineering of fuels, including the fuel cells: hydrogen, carbon monoxide, formaldehyde, formic acid/formate ions, 2-propanol, 1-butanol, hydrazine, or ethylene glycol. It can be useful to know how to avoid instabilities involving these species or, on the contrary, to profit from them. Second, electrooxidation of these molecules exhibits rich variety of nonlinear dynamic behaviors which can be treated in a model way for the sake of generalization. Third, some of these processes, under appropriate conditions, can become a source of spatial or spatiotemporal patterns on electrodes which phenomena only recently gained satisfactory explanation and description. In this chapter, we shall summarize the temporal phenomena associated with the oxidation of the above-mentioned molecules, while pattern formation will be discussed in separate Chap. 2 of volume II.Current research data indicate that such processes should be qualified as electrocatalytic, i.e., the electrode surface is actively engaged in the kinetics of the electron transfer reaction, usually involving the process taking place via the adsorbed intermediate. As in the case of other types of electrochemical oscillators, one can observe the evolution of the understanding of the source of chemical instabilitiesfrom early, sometimes oversimplified explanations oriented exclusively on the properties of the electrode/electrolyte interface toward more recent concepts, involving the analysis of the system's stability in terms of nonlinear dynamics. In particular, oscillations under galvanostatic conditions could be understood only recently in terms of the concept of the HN-NDR oscillator [1] (cf. Chap. 3).The anodic oxidation of H 2 on Pt electrode is an electrocatalytic process, in which the electron transfer is preceded by the adsorption of H 2 molecule on the active surface site. Hence, the oscillatory course of this process can be associated M. Orlik, Self-Organization in Electrochemical Systems I, Monographs in Electrochemistry,

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Potential Oscillations during the Electrocatalytic Oxidation of Sulfide on a Microstructured Ti/Ta₂O₅-IrO₂ Electrode

Cited by 64 publications

References 39 publications

Electrochemical oxidation of sulfide ion at a boron-doped diamond anode

Electrochemical oxidation of sulfide ion at a boron-doped diamond anode

Effects of Oxide Composition on Structure, Surface Morphology, and Oxygen Evolution Behaviors of IrO<sub>2</sub>-Ta<sub>2</sub>O<sub>5</sub>/Ti Anodes Prepared at a High Temperature

Temporal Instabilities in Anodic Oxidation of Small Molecules/Ions at Solid Electrodes

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