Electrochemical Synthesis of NH3 at Low Temperature and Atmospheric Pressure Using a γ-Fe2O3 Catalyst

Jimin Kong, Ahyoun Lim, Changwon Yoon, Jong Hyun Jang, Hyung Chul Ham, Jonghee Han, SukWoo Nam, Dokyoon Kim, Yung Eun Sung, Jungkyu Choi, Hyun S. Park

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118 Citations (Scopus)

Abstract

The electrochemical synthesis of NH3 by the nitrogen reduction reaction (NRR) at low temperature (<65 °C) and atmospheric pressure using nanosized γ-Fe2O3 electrocatalysts were demonstrated. The activity and selectivity of the catalyst was investigated both in a 0.1 M KOH electrolyte and when incorporated into an anion-exchange membrane electrode assembly (MEA). In a half-reaction experiment conducted in a KOH electrolyte, the γ-Fe2O3 electrode presented a faradaic efficiency of 1.9% and a weight-normalized activity of 12.5 nmol h-1 mg-1 at 0.0 VRHE. However, the selectivity toward N2 reduction decreased at more negative potentials owing to the competing proton reduction reaction. When the γ-Fe2O3 nanoparticles were coated onto porous carbon paper to form an electrode for a MEA, their weight-normalized activity for N2 reduction was found to increase dramatically to 55.9 nmol h-1 mg-1. However, the weight- and area-normalized N2 reduction activities of γ-Fe2O3 decreased progressively from 35.9 to 14.8 nmol h-1 mg-1 and from 0.105 to 0.043 nmol h-1 cm-2 act, respectively, during a 25 h MEA durability test. In summary, a study of the fundamental behavior and catalytic activity of γ-Fe2O3 nanoparticles in the electrochemical synthesis of NH3 under low temperature and pressure is presented.

Original languageEnglish
Pages (from-to)10986-10995
Number of pages10
JournalACS Sustainable Chemistry and Engineering
Volume5
Issue number11
DOIs
Publication statusPublished - 2017 Nov 6

Keywords

  • Electrocatalyst
  • Electrochemical ammonia synthesis
  • Iron oxide
  • Membrane electrode assembly

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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    Kong, J., Lim, A., Yoon, C., Jang, J. H., Ham, H. C., Han, J., Nam, S., Kim, D., Sung, Y. E., Choi, J., & Park, H. S. (2017). Electrochemical Synthesis of NH3 at Low Temperature and Atmospheric Pressure Using a γ-Fe2O3 Catalyst. ACS Sustainable Chemistry and Engineering, 5(11), 10986-10995. https://doi.org/10.1021/acssuschemeng.7b02890