Hybrid Bilayer Membrane: A Platform To Study the Role of Proton Flux on the Efficiency of Oxygen Reduction by a Molecular Electrocatalyst

Hosseini, Ali; Barile, Christopher J.; Devadoss, Anando; Eberspacher, Todd A.; Decréau, Richard A.; Collman, James P.

doi:10.1021/ja204418j

Cited by 54 publications

(40 citation statements)

References 26 publications

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“…In solution, the activity order is III > II > I (Figure S5), while on CNTs, the reverse order H1 > H3 > H4 is obtained. Second, thermodynamic potentials and reaction mechanisms of redox centers may change with pH, making activity comparison under different pH conditions complicated. Thus, we do not incline to make a direct comparison of HER and OER activities at different pH values.…”

Section: Figurementioning

confidence: 99%

Carbon Nanotubes with Cobalt Corroles for Hydrogen and Oxygen Evolution in pH 0–14 Solutions

et al. 2018

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Water splitting is promising to realize a hydrogen‐based society. The practical use of molecular water‐splitting catalysts relies on their integration onto electrode materials. We describe herein the immobilization of cobalt corroles on carbon nanotubes (CNTs) by four strategies and compare the performance of the resulting hybrids for H2 and O2 evolution. Co corroles can be covalently attached to CNTs with short conjugated linkers (the hybrid is denoted as H1) or with long alkane chains (H2), or can be grafted to CNTs via strong π–π interactions (H3) or via simple adsorption (H4). An activity trend H1≫H3>H2≈H4 is obtained for H2 and O2 evolution, showing the critical role of electron transfer ability on electrocatalysis. Notably, H1 is the first Janus catalyst for both H2 and O2 evolution reactions in pH 0–14 aqueous solutions. Therefore, this work is significant to show potential uses of electrode materials with well‐designed molecular catalysts in electrocatalysis.

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Section: Figurementioning

confidence: 99%

Carbon Nanotubes with Cobalt Corroles for Hydrogen and Oxygen Evolution in pH 0–14 Solutions

et al. 2018

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“…The ferrocene-and quinone-terminated SAMs have been prepared to study electron transfer processes between the redox moiety and the base metal [18][19][20][21]. This application as an electron mediator (e.g., in biosensors) has also been studied [22][23][24][25][26]. Moreover, ion permeability of monolayers and its relationships to the steric structure of monolayers or the size of ions have been studied [27,28].…”

Section: Introductionmentioning

confidence: 99%

A role of the membrane|solution interface in electron transfer at self-assembled monolayer modified electrodes

Shiota

Ueki

Osakai

2015

Journal of Electroanalytical Chemistry

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“…However, the incorporation of a proton carrier (i.e., decanoic acid) is required in order for the 4e − O 2 reduction to proceed (in such an HBM system, the O 2 reduction current is lower and peaks at a more negative potential). As a result, the proton carrier accelerates the rate of proton transfer (from bulk solution to the HBM-imbeded catalyst) whereas the pH of the bulk solution influences the thermodynamics of the reaction (Hosseini et al, 2011 ).…”

Section: Discussionmentioning

confidence: 99%

Three toxic gases meet in the mitochondria

Decréau

Collman

2015

Front. Physiol.

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The rationale of the study was two-fold: (i) develop a functional synthetic model of the Cytochrome c oxidase (CcO) active site, (ii) use it as a convenient tool to understand or predict the outcome of the reaction of CcO with ligands (physiologically relevant gases and other ligands). At physiological pH and potential, the model catalyzes the 4-electron reduction of oxygen. This model was immobilized on self-assembled-monolayer (SAM) modified electrode. During catalytic oxygen reduction, electron delivery through SAMs is rate limiting, similar to the situation in CcO. This model contains all three redox-active components in CcO's active site, which are required to minimize the production of partially-reduced-oxygen-species (PROS): Fe-heme (“heme a3”) in a myoglobin-like model fitted with a proximal imidazole ligand, and a distal tris-imidazole Copper (“CuB”) complex, where one imidazole is cross-linked to a phenol (mimicking “Tyr244”). This functional CcO model demonstrates how CcO itself might tolerate the hormone NO (which diffuses through the mitochondria). It is proposed that CuB delivers superoxide to NO bound to Fe-heme forming peroxynitrite, then nitrate that diffuses away. Another toxic gas, H2S, has exceptional biological effects: at ~80 ppm, H2S induces a state similar to hibernation in mice, lowering the animal's temperature and slowing respiration. Using our functional CcO model, we have demonstrated that at the same concentration range H2S can reversibly inhibit catalytic oxygen reduction. Such a reversible catalytic process on the model was also demonstrated with an organic compound, tetrazole (TZ). Following studies showed that TZ reversibly inhibits respiration in isolated mitochondria, and induces deactivation of platelets, a mitochondria-rich key component of blood coagulation. Hence, this program is a rare example illustrating the use of a functional model to understand and predict physiologically important reactions at the active site of CcO.

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Hybrid Bilayer Membrane: A Platform To Study the Role of Proton Flux on the Efficiency of Oxygen Reduction by a Molecular Electrocatalyst

Cited by 54 publications

References 26 publications

Carbon Nanotubes with Cobalt Corroles for Hydrogen and Oxygen Evolution in pH 0–14 Solutions

Carbon Nanotubes with Cobalt Corroles for Hydrogen and Oxygen Evolution in pH 0–14 Solutions

A role of the membrane|solution interface in electron transfer at self-assembled monolayer modified electrodes

Three toxic gases meet in the mitochondria

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