Redox conduction in electropolymerized films of transition-metal complexes of osmium, ruthenium, iron, and cobalt

Hurrell, Helen C.; Abruña, Héctor D.

doi:10.1021/ic00329a033

Cited by 31 publications

(9 citation statements)

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“…These results contrast to those reported using GaP semiconductors with thicker polymer coatings (on the order of ≈10 nm) ,,,, where the V oc instead decreases following pyridyl group modification of the GaP surface. We speculate that this is in part due to a larger resistance and poorer ion conductivity associated with the thicker organic coatings . Nonetheless, although the V oc of the PPy|GaP and CoTTP|PPy|GaP electrodes is similar, the fill factor (ff) of the JV response under illumination nearly doubles following treatment with CoTTP, moving from 0.21 ± 0.08 for unfunctionalized GaP to 0.23 ± 0.07 for PPy|GaP, and further increasing to 0.39 ± 0.07 for CoTTP|PPy|GaP (Figure S15 and Table S2).…”

Section: Resultsmentioning

confidence: 95%

Cobalt Porphyrin–Polypyridyl Surface Coatings for Photoelectrosynthetic Hydrogen Production

et al. 2017

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Hybrid materials that link light capture and conversion technologies with the ability to drive reductive chemical transformations are attractive as components in photoelectrosynthetic cells. We show that thin-film polypyridine surface coatings provide a molecular interface to assemble cobalt porphyrin catalysts for hydrogen evolution onto a visible-light-absorbing p-type gallium phosphide semiconductor. Spectroscopic techniques, including grazing angle attenuated total reflection Fourier transform infrared spectroscopy, confirm that the cobalt centers of the porphyrin macrocycles coordinate to pyridyl nitrogen sites of the organic surface coating. The cobalt porphyrin surface concentration and fraction of pyridyl sites coordinated to a cobalt center are quantified using complementary methods of ellipsometry, inductively coupled plasma mass spectrometry, and X-ray photoelectron spectroscopy. In aqueous solutions under simulated solar illumination the modified cathode is photochemically active for hydrogen production, generating the product gas with near-unity Faradaic efficiency at a rate of ≈10 μL min cm when studied in a three-electrode configuration and polarized at the equilibrium potential of the H/H couple. This equates to a photoelectrochemical hydrogen evolution reaction activity of 17.6 H molecules s Co, the highest value reported to date for a molecular-modified semiconductor. Key features of the functionalized photocathode include (1) the relative ease of synthetic preparation made possible by application of an organic surface coating that provides molecular recognition sites for immobilizing the cobalt porphyrin complexes at the semiconductor surface and (2) the use of visible light to drive cathodic fuel-forming reactions in aqueous solutions with no added organic acids or sacrificial chemical reductants.

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Section: Resultsmentioning

confidence: 95%

Cobalt Porphyrin–Polypyridyl Surface Coatings for Photoelectrosynthetic Hydrogen Production

et al. 2017

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“…The diameters of anions of the supporting electrolytes amount to, respectively, 0.333, 0.435, and 0.720 nm [19]. The polymers were formed at optimum potentials for the duration of 20 min in solutions containing 1 × 10 -3 M of the initial complex and 0.1 M of the supporting electrolyte.…”

Section: Effect Of Anions Of the Supporting Electrolytementioning

confidence: 99%

Structuring Redox Polymers Poly[M(Schiff)] (M = Ni, Pd; Schiff = Schiff Bases) on a Molecular Level: Methods and Results of an Investigation

et al. 2005

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This work is devoted to a consideration of methods of electrochemical synthesis of redox polymers poly[M(Schiff)], where "M" is Ni, or Pd and "Schiff" stands for a four-dentate Schiff base, with a controlled distribution of structural elements (stacks) over the electrode's surface for the optimization of the transport of charge-compensating ions, which is the stage that determines the charge transfer rate in the system under consideration. It is shown that the structuring of these polymers on a molecular level by means of a purposeful selection of the composition of the initial compounds and the conditions of synthesis-the potential of formation and the nature of the solvent and supporting electrolyte-makes it possible to a considerable extent accelerate the charge transfer process in the polymers and improve stability of their electrochemical characteristics.

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“…The relationship of the number of moles of diffusing solvent on the type of electrolyte may be related to the size of anions. The BF 4 − ion was the smallest among the investigated anions (ion diameter BF 4 − = 0.334 nm [ 46 ]). The other ions, in the presence of which mass transport takes place to a greater extent, had larger sizes (ion diameters 0.370 and 0.435 nm for ClO 4 − and PF 6 − , respectively [ 46 ]).…”

Section: Resultsmentioning

confidence: 99%

The Influence of Electrolyte Type on Kinetics of Redox Processes in the Polymer Films of Ni(II) Salen-Type Complexes

et al. 2022

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Electrodes modified with polymers derived from the complexes [Ni(salcn)], [Ni(salcn(Me))] and [Ni(salcn(Bu))] were obtained in order to study the kinetics of electrode processes occurring in polymer films, depending on the thickness of the films, the type of electrolyte and the solvent. FTIR and EQCM methods were used to determine the type of mass transported into polymer films during anode processes and the number of moles of ions and solvent. The rate of charge transport through films was determined by the cyclic voltammetry method, by the quantity cD1/2. It was shown that the charge transport was determined by the transport of anions. The kinetics were most efficient for poly[Ni(salcn(Bu))] modified electrodes, obtained from TBAPF6 and working in TBAClO4 and TBABF4. It was also shown that a solvent with a higher DN value and lower viscosity (MeCN) facilitated the transport of the charge through polymer films.

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Redox conduction in electropolymerized films of transition-metal complexes of osmium, ruthenium, iron, and cobalt

Cited by 31 publications

References 0 publications

Cobalt Porphyrin–Polypyridyl Surface Coatings for Photoelectrosynthetic Hydrogen Production

Cobalt Porphyrin–Polypyridyl Surface Coatings for Photoelectrosynthetic Hydrogen Production

Structuring Redox Polymers Poly[M(Schiff)] (M = Ni, Pd; Schiff = Schiff Bases) on a Molecular Level: Methods and Results of an Investigation

The Influence of Electrolyte Type on Kinetics of Redox Processes in the Polymer Films of Ni(II) Salen-Type Complexes

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