期刊
JOURNAL OF CATALYSIS
卷 404, 期 -, 页码 362-370出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcat.2021.10.017
关键词
Electrochemistry; DFT calculations; Ammonia; Nitrogen reduction reaction; Hydrogen evolution; Electrocatalysis
资金
- Icelandic Research Fund [196437-051]
- Doctoral Fund of the University of Iceland
Density functional theory calculations were used to investigate the elementary kinetics of nitrogen reduction and hydrogen evolution on the W(110) surface, revealing that protonation of adsorbed NH is rate-limiting for nitrogen reduction. The largest barrier found for hydrogen evolution at high hydrogen coverage is 0.36 eV, indicating that hydrogen evolution is expected to dominate over nitrogen reduction on W(110) at negative potentials.
Elucidating the elementary kinetics of nitrogen reduction on transition metal surfaces can guide the search for materials capable of efficiently catalysing electrochemical ammonia synthesis at ambient conditions. Density functional theory calculations are used here to explore the elementary kinetics of nitrogen reduction and hydrogen evolution on W(110). All proton-electron transfer barriers are calculated at-0.7 V vs. SHE, where the cathodic potential is explicitly modelled using a solvation bilayer of water with hydronium ions. The protonation of adsorbed NH is determined to be rate-limiting for nitrogen reduction, with a barrier of 0.65 eV. The same reaction step is potential-limiting based on the thermochemistry of adsorbed intermediates only, showing that thermochemical calculations suffice to predict catalytic trends for nitrogen reduction. The largest barrier found for hydrogen evolution at high hydrogen coverage is 0.36 eV. Thus, hydrogen evolution is expected to dominate over nitrogen reduction on W(110) at negative potentials. (c) 2021 Elsevier Inc. All rights reserved.
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