Enhancement of the Electrocatalytic Activity of Thienyl‐Substituted Iron Porphyrin Electropolymers by a Hangman Effect

Neumann, Bettina; Götz, Robert; Wrzolek, Pierre; Scheller, Frieder W.; Weidinger, Inez M.; Schwalbe, Matthias; Wollenberger, Ulla

doi:10.1002/cctc.201800934

Cited by 9 publications

(7 citation statements)

References 64 publications

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“…Iron tetramesitylporphyrin (FeTMP) and iron tetrakis(3-thienyl)porphyrin (FeT3ThP) were synthesized according to published procedures. ,,− Briefly, the free base porphyrins were reacted with iron(II) chloride in dimethylformamide under argon atmosphere. Aerobic acidic workup yields the corresponding chloroiron(III) porphyrin complexes, shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly electrochemical RR measurements of dropcasted BPG|FeT3ThP (Figure S8) showed no potential dependent redox changes. On BPG electrodes no surface enhancement effect is present but due to the high Resonance Raman signal intensity of porphyrin modes upon 413 nm laser excitation, good Raman spectra can nevertheless be obtained if the number of layers is high enough . In this case, the data gives information on all layers equally and suggests that outer layers are not electronically accessible and thus do not participate in the ORR.…”

Section: Resultsmentioning

confidence: 99%

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Influence of Mesityl and Thiophene Peripheral Substituents on Surface Attachment, Redox Chemistry, and ORR Activity of Molecular Iron Porphyrin Catalysts on Electrodes

Götz

Wrzolek

et al. 2019

Inorg. Chem.

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Two iron porphyrin complexes with either mesityl (FeTMP) or thiophene (FeT3ThP) peripheral substituents were attached to basal pyrolytic graphite and Ag electrodes via different immobilization methods. By combining cyclic voltammetry and in-operando surface-enhanced Raman spectroscopy along with MD simulations and DFT calculations, their respective surface attachment, redox chemistry and activity toward electrocatalytic oxygen reduction was investigated. For both porphyrin complexes, it could be shown that catalytic activity is restricted to the first (few) molecular layer(s), although electrodes covered with thiophene-substituted complexes showed a better capability to consume the oxygen at a given overpotential even in thicker films. The spectroscopic data and simulations suggest that both porphyrin complexes attach to a Ag electrode surface in a way that maximum planarity and minimum distance between the catalytic iron site and the electrode is achieved. However, due to the distinctive design of the FeT3ThP complex, the thiophene rings are capable of occupying a conformation, via rotation around the bonding axis to the porphyrin, in which all four sulfur atoms can coordinate to the Ag surface. This effect creates a dense and planar surface coverage of the porphyrin on the electrode facilitating a fast (multi) electron transfer via several covalent Ag–S bonds. In contrast, bulky mesityl groups as peripheral substituents, which have been initially introduced to prevent aggregation and improve catalytic behavior in solution, exert a negative effect on the overall electrocatalytic performance in the immobilized state as a less dense coverage and less stable interactions with the surface are formed. Our results underline the importance of rationally designed heterogenized molecular catalysts to achieve optimal turnover, which not only strictly applies to the here discussed oxygen reduction reaction but eventually holds also true for other energy conversion reactions such as carbon dioxide reduction.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Influence of Mesityl and Thiophene Peripheral Substituents on Surface Attachment, Redox Chemistry, and ORR Activity of Molecular Iron Porphyrin Catalysts on Electrodes

Götz

Wrzolek

et al. 2019

Inorg. Chem.

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“…Similar to semisynthetic MPs, other artificial systems like mimochromes [261][262][263][264], synthetic porphyrins, or hemin [265][266][267][268][269], showed reactivity toward H 2 O 2 and have been used as biological component in DET-based biosensors.…”

Section: Cytochrome C and Microperoxidasesmentioning

confidence: 99%

Electrocatalysis by Heme Enzymes—Applications in Biosensing

et al. 2021

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Heme proteins take part in a number of fundamental biological processes, including oxygen transport and storage, electron transfer, catalysis and signal transduction. The redox chemistry of the heme iron and the biochemical diversity of heme proteins have led to the development of a plethora of biotechnological applications. This work focuses on biosensing devices based on heme proteins, in which they are electronically coupled to an electrode and their activity is determined through the measurement of catalytic currents in the presence of substrate, i.e., the target analyte of the biosensor. After an overview of the main concepts of amperometric biosensors, we address transduction schemes, protein immobilization strategies, and the performance of devices that explore reactions of heme biocatalysts, including peroxidase, cytochrome P450, catalase, nitrite reductase, cytochrome c oxidase, cytochrome c and derived microperoxidases, hemoglobin, and myoglobin. We further discuss how structural information about immobilized heme proteins can lead to rational design of biosensing devices, ensuring insights into their efficiency and long-term stability.

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“…4d. 44,49 Electrochemical reduction of CO 2 .-Electrochemical methods are useful tools for the reduction of CO 2 to other substances such as CO, CH 3 OH, C 2 H 5 OH, an etc. 50 The effect of metal (Co)-containing and metal-free porphyrin polymers on electrochemical CO 2 reduction was investigated using LSV method between 0 and −1.8 V vs Ag/AgCl (in 3 M KCl) with 5 mV.s −1 scanning rate in this work.…”

Section: Resultsmentioning

confidence: 99%

Thiophene Functionalized Porphyrin for Electrochemical Carbon Dioxide Reduction

Kaplan

Gümrükçü

Gençten

et al. 2021

J. Electrochem. Soc.

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The production of catalysts that display strong efficiencies in aqueous media for the electrochemical carbon dioxide reduction reaction (CO2RR) is essential both for a healthy world and for realistic application of energy waste to generate value-added fuels. In this study, thiophene functionalized metal-free (poly-H2Por) and cobalt porphyrin-based (poly-CoPor) organometallic catalysts were easily attached on the pencil graphite electrode surface via electrochemical polymerization method and these, porphyrin coated, pencil graphite electrodes (PGE) were used as electrocatalysts for electrochemical CO2 reduction for the first time in the literature. To reveal the electrochemical activity of CO2RR, the electropolymerized catalysts were investigated with linear sweep voltammetry in 0.1 M KHCO3 solution. The results showed that, the electrode which is modified with poly-CoPor decreased the overpotential of CO2RR, according to bare pencil graphite electrode, from -1.35 V to -0.63 V.

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Enhancement of the Electrocatalytic Activity of Thienyl‐Substituted Iron Porphyrin Electropolymers by a Hangman Effect

Cited by 9 publications

References 64 publications

Influence of Mesityl and Thiophene Peripheral Substituents on Surface Attachment, Redox Chemistry, and ORR Activity of Molecular Iron Porphyrin Catalysts on Electrodes

Influence of Mesityl and Thiophene Peripheral Substituents on Surface Attachment, Redox Chemistry, and ORR Activity of Molecular Iron Porphyrin Catalysts on Electrodes

Electrocatalysis by Heme Enzymes—Applications in Biosensing

Thiophene Functionalized Porphyrin for Electrochemical Carbon Dioxide Reduction

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