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Title: Increasing the rate of hydrogen oxidation without increasing the overpotential: A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay

Abstract

Oxidation of hydrogen (H₂) to protons and electrons for energy production in fuel cells is catalyzed by platinum, but its low abundance and high cost present drawbacks to widespread adoption. Precisely controlled proton delivery and removal is critical in hydrogenase enzymes in nature that catalyze H₂ oxidation using earth-abundant metals (iron and nickel). Here we report a synthetic iron complex, (Cp C5F4N)Fe(P EtN (CH2)3NMe2PEt)(Cl), that serves as a precatalyst for the oxidation of H₂, with turnover frequencies of 290 s⁻¹ in fluorobenzene, under 1 atm of H₂ using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the exogenous base. The cooperative effect of the primary, secondary and outer coordination spheres for moving protons in this remarkably fast catalyst emphasizes the key role of pendant amines in mimicking the functionality of the proton pathway in the hydrogenase enzymes.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1203861
Report Number(s):
PNNL-SA-105708
Journal ID: ISSN 2041-6520; CSHCBM; KC0307010
Grant/Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 6; Journal Issue: 5; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 30 DIRECT ENERGY CONVERSION; homogeneous catalysis; hydrogen oxidation; proton transport; iron; diphosphine; outer coordination sphere

Citation Formats

Darmon, Jonathan M., Kumar, Neeraj, Hulley, Elliott B., Weiss, Charles J., Raugei, Simone, Bullock, R. Morris, and Helm, Monte L. Increasing the rate of hydrogen oxidation without increasing the overpotential: A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay. United States: N. p., 2015. Web. doi:10.1039/C5SC00398A.
Darmon, Jonathan M., Kumar, Neeraj, Hulley, Elliott B., Weiss, Charles J., Raugei, Simone, Bullock, R. Morris, & Helm, Monte L. Increasing the rate of hydrogen oxidation without increasing the overpotential: A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay. United States. doi:10.1039/C5SC00398A.
Darmon, Jonathan M., Kumar, Neeraj, Hulley, Elliott B., Weiss, Charles J., Raugei, Simone, Bullock, R. Morris, and Helm, Monte L. Thu . "Increasing the rate of hydrogen oxidation without increasing the overpotential: A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay". United States. doi:10.1039/C5SC00398A. https://www.osti.gov/servlets/purl/1203861.
@article{osti_1203861,
title = {Increasing the rate of hydrogen oxidation without increasing the overpotential: A bio-inspired iron molecular electrocatalyst with an outer coordination sphere proton relay},
author = {Darmon, Jonathan M. and Kumar, Neeraj and Hulley, Elliott B. and Weiss, Charles J. and Raugei, Simone and Bullock, R. Morris and Helm, Monte L.},
abstractNote = {Oxidation of hydrogen (H₂) to protons and electrons for energy production in fuel cells is catalyzed by platinum, but its low abundance and high cost present drawbacks to widespread adoption. Precisely controlled proton delivery and removal is critical in hydrogenase enzymes in nature that catalyze H₂ oxidation using earth-abundant metals (iron and nickel). Here we report a synthetic iron complex, (CpC5F4N)Fe(PEtN(CH2)3NMe2PEt)(Cl), that serves as a precatalyst for the oxidation of H₂, with turnover frequencies of 290 s⁻¹ in fluorobenzene, under 1 atm of H₂ using 1,4-diazabicyclo[2.2.2]octane (DABCO) as the exogenous base. The cooperative effect of the primary, secondary and outer coordination spheres for moving protons in this remarkably fast catalyst emphasizes the key role of pendant amines in mimicking the functionality of the proton pathway in the hydrogenase enzymes.},
doi = {10.1039/C5SC00398A},
journal = {Chemical Science},
number = 5,
volume = 6,
place = {United States},
year = {Thu Mar 05 00:00:00 EST 2015},
month = {Thu Mar 05 00:00:00 EST 2015}
}

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Cited by: 19 works
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Works referenced in this record:

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