TY - JOUR
T1 - Evaluating the Thermodynamics of Electrocatalytic N2 Reduction in Acetonitrile
AU - Lindley, Brian M.
AU - Appel, Aaron M.
AU - Krogh-Jespersen, Karsten
AU - Mayer, James M.
AU - Miller, Alexander J.M.
N1 - Funding Information:
B.M.L., K.K.-J., J.M.M., and A.J.M.M. gratefully acknowledge support from the NSF Center for Enabling New Technologies through Catalysis (CENTC), CHE-1205189. For A.M.A., this research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/14
Y1 - 2016/10/14
N2 - The development of a sustainable ammonia synthesis by proton-coupled electroreduction of dinitrogen (N2) requires knowledge of the thermodynamics described by standard reduction potentials. The first collection of N2 reduction standard potentials in an organic solvent are reported here. The potentials for reduction of N2 to ammonia (NH3), hydrazine (N2H4), and diazene (N2H2) in acetonitrile (MeCN) solution are derived using thermochemical cycles. Ammonia is thermodynamically favored, with a 0.43 V difference between NH3 and N2H4 and a 1.26 V difference between NH3 and N2H2. The thermodynamics for reduction of N2 to the protonated products ammonium (NH4 +) and hydrazinium (N2H5 +) under acidic conditions are also presented. Comparison with the H+/H2 potential in MeCN reveals a 63 mV thermodynamic preference for N2 reduction to NH3 over H2 production. Combined with knowledge of the kinetics of electrode-catalyzed H2 evolution, a wide working region is identified to guide future electrocatalytic studies.
AB - The development of a sustainable ammonia synthesis by proton-coupled electroreduction of dinitrogen (N2) requires knowledge of the thermodynamics described by standard reduction potentials. The first collection of N2 reduction standard potentials in an organic solvent are reported here. The potentials for reduction of N2 to ammonia (NH3), hydrazine (N2H4), and diazene (N2H2) in acetonitrile (MeCN) solution are derived using thermochemical cycles. Ammonia is thermodynamically favored, with a 0.43 V difference between NH3 and N2H4 and a 1.26 V difference between NH3 and N2H2. The thermodynamics for reduction of N2 to the protonated products ammonium (NH4 +) and hydrazinium (N2H5 +) under acidic conditions are also presented. Comparison with the H+/H2 potential in MeCN reveals a 63 mV thermodynamic preference for N2 reduction to NH3 over H2 production. Combined with knowledge of the kinetics of electrode-catalyzed H2 evolution, a wide working region is identified to guide future electrocatalytic studies.
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U2 - 10.1021/acsenergylett.6b00319
DO - 10.1021/acsenergylett.6b00319
M3 - Article
AN - SCOPUS:85021355019
VL - 1
SP - 698
EP - 704
JO - ACS Energy Letters
JF - ACS Energy Letters
SN - 2380-8195
IS - 4
ER -