Galvani potential scales for water—nitrobenzene and water-1,2-dichloroethane interfaces

Wandlowski, Thomas; Mareček, Vladimı́r; Samec, Zdeněk

doi:10.1016/0013-4686(90)80035-m

Cited by 183 publications

(164 citation statements)

References 18 publications

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“…Therefore, they can be [14,15] Shake flask experiments: [CoA C H T U N G T R E N N U N G (tpp)] catalyzed O 2 reductions by Fc, DFc and DMFc at a water j DCE interface at which the polarization was chemically controlled by a common ion, so called shake flask experiments, were performed as reported previously. [28] Dissolving lithium tetrakis(pentafluorophenyl)borate (LiTPFB, 5 mm) and HCl (10 mm) in water and BTPPATPFB (5 mm) in DCE (water/ DCE = 1:1 in volume), the Galvani potential difference across the interface is fixed by the common ion TPFB À at a potential greater than 0.59 V. [28,32] At this potential, proton initially present in water will partition into DCE, leading finally to a distribution of proton in two phases according to the Nernst equation. If only [CoA C H T U N G T R E N N U N G (tpp)] is present in DCE, a Soret band (l max = 427 nm) and a Q band (l max = 540 nm) are observed after the shake flask experiment, which demonstrates a bathochromic shift relative to those of a fresh [Co-A C H T U N G T R E N N U N G (tpp)] solution at 410 nm and 526 nm, as shown in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

Proton Pump for O₂ Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Partovi‐Nia

et al. 2009

Chemistry A European J

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Oxygen reduction: A polarized water|1,2‐dichloroethane (DCE) interface acts as a proton pump for the [Co(tpp)] (TPP=5,10,15,20‐tetraphenylporphyrinato) catalyzed O2 reduction by ferrocene (Fc) compounds to produce H2O2 (see figure; IT=ion transfer, ET=electron transfer). This system favours the collection of H2O2 by extraction immediately after its formation in DCE to the adjacent water phase.magnified imageThe role of 5,10,15,20‐tetraphenylporphyrinatocobalt(II) ([Co(tpp)]) as a catalyst on molecular oxygen (O2) reduction by ferrocene (Fc) and its two derivatives, 1,1′‐dimethylferrocene (DFc) and decamethylferrocene (DMFc) at a polarized water|1,2‐dichloroethane (DCE) interface has been studied. The water|DCE interface essentially acts as a proton pump controlled by the Galvani potential difference across the interface, driving the proton transfer from water to DCE. [Co(tpp)] catalyzed O2 reduction by Fc, DFc and DMFc is then followed to produce hydrogen peroxide (H2O2). The catalytic mechanism is similar to that proposed by Fukuzumi et al. for bulk reactions. This interfacial system provides a platform for a very efficient collection of H2O2, by extraction immediately after its formation in DCE to the adjacent water phase, thus decreasing the possibility of degradation and further reaction with ferrocene derivatives.

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Section: Resultsmentioning

confidence: 99%

Proton Pump for O₂ Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Partovi‐Nia

et al. 2009

Chemistry A European J

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“…6. This observation led them to conclude that the ion must overcome Samec et al 53,54 published two papers on the kinetics of ion transfer across the water-nitrobenzene interface, using ac impedance measurements at the equilibrium potentials. The latter were determined by the Nemst equation for ionic equilibria, where the concentration ratio of the crossing ion in both phases was varied:…”

Section: Rt(o In Kf)mentioning

confidence: 99%

Charge Transfer across Liquid—Liquid Interfaces

Girault¹

1993

Modern Aspects of Electrochemistry

106

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“…Under such conditions, the water/ DCE interface is polarized positively, [18] and TB À acts as a pump to drive H + from the aqueous phase to the DCE phase, forming the organic acid HTB. Evidence of the enhancement in rate of the oxidation of the electron donors by GO is clearly seen by comparing the UV/Vis spectra of the organic products [either decamethylferrocenium (DMFc + ) or Fc + ions, pre-and post-shake-flask, with and without GO present] and noting the increased production of the biphasic reaction (l max = 779 and 620 nm, respectively) in the presence of GO (see Figure SI-4.1 in the Supporting Information).…”

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confidence: 99%

Oxygen Reduction at Soft Interfaces Catalyzed by In Situ‐Generated Reduced Graphene Oxide

et al. 2013

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Graphene oxide (GO) in water was reduced heterogeneously by decamethylferrocene (DMFc) or ferrocene (Fc) in 1,2-dichloroethane (DCE), which could then act as a catalyst for an interfacial oxygen reduction reaction (ORR) and production of hydrogen peroxide (H 2 O 2 ). The reduced graphene oxide (RGO) produced at the liquid/liquid interface was characterized by using electron microscopy, spectroscopy (Raman, infrared, and electron energy loss), and electrochemical techniques.The oxygenated functional groups at the edge/defects of the RGO surface activate O 2 adsorption, forming superoxidelike adducts that can be protonated at the liquid/liquid interface and reduced by DMFc or Fc. This process is facilitated by the higher electrical conductivity of the RGO sheets. The key feature of this catalytic reaction is the in situ partial-reduction of GO at the liquid/liquid interface, forming an efficient and inexpensive catalyst for the production of H 2 O 2 .Electrochemistry at polarized interfaces between two immiscible electrolyte solutions (ITIES) has developed over the past 30 years, in which charge-transfer (electron-and ion-transfer) reactions have found applications in areas such as phase-transfer catalysis, solvent-extraction processes, chemical sensing, solar-energy-conversion systems, drug release and delivery, and in mimicking the function of biological membranes. [1] Liquid/liquid interfaces provide a unique platform at which to study ORRs, at which aqueous protons react with organic solubilized electron donors in the absence or presence of adsorbed catalysts, usually through a proton-coupled electron-transfer (PCET) reaction. [2] The molecular catalysts studied include cobalt, [3] free-base porphyrins, [4] and in situ-deposited platinum particles. [5] The ORR proceeds either by a 4 e À /4 H + pathway to produce water or a 2 e À /2 H + route to yield H 2 O 2 , which is considered a green oxidant.H 2 O 2 is widely used in many industrial areas, particularly in the chemical industry or for environmental protection, and is currently produced on an industrial scale through the biphasic anthrahydroquinone oxidation (AO) process (representing ca. 95 % of the world's H 2 O 2 production). [6] Generally, anthrahydroquinone is oxidized by O 2 to produce H 2 O 2 and anthraquinone and, subsequently, the formed anthraquinone is reduced back to the anthrahydroquinone by using H 2 in the presence of a metal catalyst. Both reactions occur in the organic phase, and H 2 O 2 is recovered by extraction to the aqueous phase. [6] The advantage of the AO process is the very high yield of H 2 O 2 generated per cycle. Conversely, side reactions generating organic byproducts need to be dealt with by regenerating the solution and by using separation techniques to eliminate such impurities. Conceptually, following the AO process, the reduction of O 2 was investigated at quinone-modified carbon surfaces. O 2 reduction to H 2 O 2 was mediated by surface-bound quinone groups via superoxide anion intermediates, [7] and such modified elec...

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Galvani potential scales for water—nitrobenzene and water-1,2-dichloroethane interfaces

Cited by 183 publications

References 18 publications

Proton Pump for O₂ Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Proton Pump for O₂ Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Charge Transfer across Liquid—Liquid Interfaces

Oxygen Reduction at Soft Interfaces Catalyzed by In Situ‐Generated Reduced Graphene Oxide

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Galvani potential scales for water—nitrobenzene and water-1,2-dichloroethane interfaces

Cited by 183 publications

References 18 publications

Proton Pump for O2 Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Proton Pump for O2 Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Charge Transfer across Liquid—Liquid Interfaces

Oxygen Reduction at Soft Interfaces Catalyzed by In Situ‐Generated Reduced Graphene Oxide

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Proton Pump for O₂ Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)

Proton Pump for O₂ Reduction Catalyzed by 5,10,15,20‐Tetraphenylporphyrinatocobalt(II)