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Atomic Molybdenum for Synthesis of Ammonia with 50% Faradic Efficiency

Journal Article · · Small
 [1];  [1];  [1];  [2];  [1];  [1]
  1. Rice Univ., Houston, TX (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)

The electrochemical dinitrogen (N2) reduction reaction (NRR) under ambient conditions has gained significant interest as an environmentally friendly alternative to the traditional Haber–Bosch process for the synthesis of ammonia (NH3). However, up to now, most of the reported NRR electrocatalysts with satisfactory catalytic activities have been hindered by the large overpotential in N2 activation. The preparation of highly efficient Mo-based NRR electrocatalyst in acidic electrolytes under ambient conditions is demonstrated here, consisting of stabilized single Mo atoms anchored on holey nitrogen-doped graphene synthesized through a convenient potassium-salt-assisted activation method. At -0.05 V versus a reversible hydrogen electrode (RHE), an electrode consisting of the resultant electrocatalyst immobilized on carbon fiber paper can attain an exceptional Faradaic efficiency of 50.2% and a NH3 yield rate of 3.6 µg h-1 mgcat-1 with low overpotentials. Density functional theory calculations further unveil that compared to the original graphene without holes, the edge coordinated Mo atoms and the existence of vacancies on holey graphene lower the overpotential of N2 reduction, thereby promoting the NRR catalytic activity. Finally, this work could provide new guidelines for future designs in single-atom catalysis that would be beneficial to ambient N2 fixation, and replacement of classical synthesis processes that are very energy-intensive.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); US Air Force Office of Scientific Research (AFOSR)
Grant/Contract Number:
SC0012704
OSTI ID:
1889637
Alternate ID(s):
OSTI ID: 1854640
Report Number(s):
BNL-223488-2022-JAAM
Journal Information:
Small, Journal Name: Small Journal Issue: 15 Vol. 18; ISSN 1613-6810
Publisher:
WileyCopyright Statement
Country of Publication:
United States
Language:
English

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