TY - JOUR
T1 - On the mechanism of the electrochemical conversion of ammonia to dinitrogen on Pt(1 0 0) in alkaline environment
AU - Katsounaros, Ioannis
AU - Figueiredo, Marta C.
AU - Calle-Vallejo, Federico
AU - Li, Hongjiao
AU - Gewirth, Andrew A.
AU - Markovic, Nenad M.
AU - Koper, Marc T.M.
N1 - Funding Information:
This research was supported by a Marie Curie International Outgoing Fellowship within the seventh European Community Framework Programme to I.K. under Award IOF-327650, and by the U.S. Department of Energy , Office of Science, Materials Sciences and Engineering Division (contract DE-AC02-06CH11357). H. L. acknowledges support from the China Scholarship Council through a CSC scholarship. F.C.-V. acknowledges funding from The Netherlands Organization for Scientific Research (NWO), Veni project number 722.014.009. F.C.V. also thanks Spanish MEC for a Ramón y Cajal research contract RYC-2015-18996. The use of supercomputing facilities at SURFsara was sponsored by NWO Physical Sciences, with financial support by NWO.
Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2018/3
Y1 - 2018/3
N2 - The electrochemical oxidation of ammonia to dinitrogen is a model reaction for the electrocatalysis of the nitrogen cycle, as it can contribute to the understanding of the making/breaking of N–N, N–O, or N–H bonds. Moreover, it can be used as the anode reaction in ammonia electrolyzers for H2 production or in ammonia fuel cells. We study here the reaction on the N2-forming Pt(1 0 0) electrode using a combination of electrochemical methods, product characterization and computational methods, and suggest a mechanism that is compatible with the experimental and theoretical findings. We propose that N2 is formed via an ∗NH + ∗NH coupling step, in accordance with the Gerischer-Mauerer mechanism. Other N–N bond-forming steps are considered less likely based on either their unfavourable energetics or the low coverage of the necessary monomers. The N–N coupling is inhibited by strongly adsorbed ∗N and ∗NO species, which are formed by further oxidation of ∗NH.
AB - The electrochemical oxidation of ammonia to dinitrogen is a model reaction for the electrocatalysis of the nitrogen cycle, as it can contribute to the understanding of the making/breaking of N–N, N–O, or N–H bonds. Moreover, it can be used as the anode reaction in ammonia electrolyzers for H2 production or in ammonia fuel cells. We study here the reaction on the N2-forming Pt(1 0 0) electrode using a combination of electrochemical methods, product characterization and computational methods, and suggest a mechanism that is compatible with the experimental and theoretical findings. We propose that N2 is formed via an ∗NH + ∗NH coupling step, in accordance with the Gerischer-Mauerer mechanism. Other N–N bond-forming steps are considered less likely based on either their unfavourable energetics or the low coverage of the necessary monomers. The N–N coupling is inhibited by strongly adsorbed ∗N and ∗NO species, which are formed by further oxidation of ∗NH.
KW - Ammonia oxidation
KW - Electrocatalysis
KW - Nitrogen cycle
KW - Physical electrochemistry
KW - Single-crystal electrochemistry
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U2 - 10.1016/j.jcat.2017.12.028
DO - 10.1016/j.jcat.2017.12.028
M3 - Article
AN - SCOPUS:85041414154
SN - 0021-9517
VL - 359
SP - 82
EP - 91
JO - Journal of Catalysis
JF - Journal of Catalysis
ER -