Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N , N -Dimethylformamide

Pegis, Michael L.; Roberts, John A. S.; Wasylenko, Derek J.; Mader, Elizabeth A.; Appel, Aaron M.; Mayer, James M.

doi:10.1021/acs.inorgchem.5b02136

Title: Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N , N -Dimethylformamide

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Abstract

A variety of next-generation energy processes utilize the electrochemical interconversions of dioxygen and water as the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Reported here are the first estimates of the standard reduction potential of the O₂ + 4e^– + 4H⁺ ⇌ 2H₂O couple in organic solvents. The values are +1.21 V in acetonitrile (MeCN) and +0.60 V in N,N-dimethylformamide (DMF), each versus the ferrocenium/ferrocene couple (Fc^+/0) in the respective solvent (as are all of the potentials reported here). The potentials have been determined using a thermochemical cycle that combines the free energy for transferring water from aqueous solution to organic solvent, –0.43 kcal mol^–1 for MeCN and –1.47 kcal mol^–1 for DMF, and the potential of the H⁺/H₂ couple, – 0.028 V in MeCN and –0.662 V in DMF. The H⁺/H₂ couple in DMF has been directly measured electrochemically using the previously reported procedure for the MeCN value. The thermochemical approach used for the O₂/H₂O couple has been extended to the CO₂/CO and CO₂/CH₄ couples to give values of –0.12 and +0.15 V in MeCN and –0.73 and –0.48 V in DMF, respectively. Here, extensions to other reduction potentials are discussed. Additionally, the free energy formore »« less

Authors:

Pegis, Michael L. ^[1]; Roberts, John A. S. ^[2]; Wasylenko, Derek J. ^[3]; Mader, Elizabeth A. ^[1]; Appel, Aaron M. ^[2]; Mayer, James M. ^[1]

Department of Chemistry, Yale University, PO Box 208107, New Haven, Connecticut 06520-8107, United States
Center for Molecular Electrocatalysis, Pacific Northwest National Laboratory, P.O. Box 999 (K2-57), Richland, Washington 99352, United States
Department of Chemistry, University of Washington, Campus Box 351700, Seattle, Washington 98195-1700, United States

Publication Date:: Mon Dec 07 00:00:00 EST 2015

Research Org.:: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Molecular Electrocatalysis (CME)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1228284

Alternate Identifier(s):: OSTI ID: 1255410

Report Number(s):: PNNL-SA-111283
Journal ID: ISSN 0020-1669

Grant/Contract Number:: AC05-76RL01830

Resource Type:: Published Article

Journal Name:: Inorganic Chemistry

Additional Journal Information:: Journal Name: Inorganic Chemistry Journal Volume: 54 Journal Issue: 24; Journal ID: ISSN 0020-1669

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; oxygen reduction; thermodynamic potentials

Citation Formats


                    Pegis, Michael L., Roberts, John A. S., Wasylenko, Derek J., Mader, Elizabeth A., Appel, Aaron M., and Mayer, James M. Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N , N -Dimethylformamide.  United States: N. p., 2015. 
Web.  doi:10.1021/acs.inorgchem.5b02136.

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                    Pegis, Michael L., Roberts, John A. S., Wasylenko, Derek J., Mader, Elizabeth A., Appel, Aaron M., & Mayer, James M. Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N , N -Dimethylformamide.  United States.  https://doi.org/10.1021/acs.inorgchem.5b02136

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                    Pegis, Michael L., Roberts, John A. S., Wasylenko, Derek J., Mader, Elizabeth A., Appel, Aaron M., and Mayer, James M. Mon .  
"Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N , N -Dimethylformamide".  United States.  https://doi.org/10.1021/acs.inorgchem.5b02136.

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@article{osti_1228284,

  title        = {Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N , N -Dimethylformamide},

  author       = {Pegis, Michael L. and Roberts, John A. S. and Wasylenko, Derek J. and Mader, Elizabeth A. and Appel, Aaron M. and Mayer, James M.},

  abstractNote = {A variety of next-generation energy processes utilize the electrochemical interconversions of dioxygen and water as the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Reported here are the first estimates of the standard reduction potential of the O2 + 4e– + 4H+ ⇌ 2H2O couple in organic solvents. The values are +1.21 V in acetonitrile (MeCN) and +0.60 V in N,N-dimethylformamide (DMF), each versus the ferrocenium/ferrocene couple (Fc+/0) in the respective solvent (as are all of the potentials reported here). The potentials have been determined using a thermochemical cycle that combines the free energy for transferring water from aqueous solution to organic solvent, –0.43 kcal mol–1 for MeCN and –1.47 kcal mol–1 for DMF, and the potential of the H+/H2 couple, – 0.028 V in MeCN and –0.662 V in DMF. The H+/H2 couple in DMF has been directly measured electrochemically using the previously reported procedure for the MeCN value. The thermochemical approach used for the O2/H2O couple has been extended to the CO2/CO and CO2/CH4 couples to give values of –0.12 and +0.15 V in MeCN and –0.73 and –0.48 V in DMF, respectively. Here, extensions to other reduction potentials are discussed. Additionally, the free energy for transfer of protons from water to organic solvent is estimated as +14 kcal mol–1 for acetonitrile and +0.6 kcal mol–1 for DMF.},

  doi          = {10.1021/acs.inorgchem.5b02136},

  journal      = {Inorganic Chemistry},

  number       = 24,

  volume       = 54,

  place        = {United States},

  year         = {Mon Dec 07 00:00:00 EST 2015},

  month        = {Mon Dec 07 00:00:00 EST 2015}

}

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