Nonstoichiometric Uranium Dinitride as a Potential Catalyst for Ammonia Synthesis: A Theoretical Study of Surface Science
- 1Univ. Lille CNRS Centrale Lille Univ. Artois UMR8181 – UCCS – Unité de Catalyse et Chimie du Solide Lille France
Abstract
Uranium nitrides UN2−x are excellent candidates as catalyst for ammonia synthesis, as demonstrated by their historical precedent. However, despite their potential, uranium nitrides have not been extensively investigated. In this study, we theoretically investigated the bulk and surface properties of pure and defective UN2 (UN1.75) implementing DFT + U approach. Uranium nitride UN2 is not stable, and vacancies are spontaneously formed leading to N/U ratio between 1.7 and 1.8 depending on the synthesis conditions. The vacancy formation energy of UN2 was calculated as −0.70 eV. To identify the most stable surface, surface energy was calculated for both UN2 and UN1.75 catalyst built in four Miller indices (100), (110), (111), and (121). It was found that (111) surface is the most stable one. Moreover, considering differences in distribution of vacancies in UN1.75, a random vacancy distribution for (111) surface shows the lower surface energy of 0.51 J.m−2. The surface can easily be covered by layer of oxygen at very low oxygen pressure even at high temperature of 1500 K. However, the regeneration of the initial deoxygenated surface is possible under reaction conditions, (N2/H2; 1:3) at 1000 K temperature. Regeneration is further facilitated in the presence of ammonia in the gas mixture.
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BibTeX
@article{promie2026nonstoichiometric,
title = {{Nonstoichiometric Uranium Dinitride as a Potential Catalyst for Ammonia Synthesis: A Theoretical Study of Surface Science}},
author = {Ahsan Rajib Promie and Guillaume Pomalaza and Jean‐François Paul},
journal = {Chemphyschem},
year = {2026},
month = oct,
doi = {10.1002/cphc.70594},
url = {https://doi.org/10.1002/cphc.70594},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Nonstoichiometric Uranium Dinitride as a Potential Catalyst for Ammonia Synthesis: A Theoretical Study of Surface Science
AU - Ahsan Rajib Promie
AU - Guillaume Pomalaza
AU - Jean‐François Paul
PY - 2026
DA - 2026/10/27
JO - Chemphyschem
DO - 10.1002/cphc.70594
UR - https://doi.org/10.1002/cphc.70594
AB - Uranium nitrides UN2−x are excellent candidates as catalyst for ammonia synthesis, as demonstrated by their historical precedent. However, despite their potential, uranium nitrides have not been extensively investigated. In this study, we theoretically investigated the bulk and surface properties of pure and defective UN2 (UN1.75) implementing DFT + U approach. Uranium nitride UN2 is not stable, and vacancies are spontaneously formed leading to N/U ratio between 1.7 and 1.8 depending on the synthesis conditions. The vacancy formation energy of UN2 was calculated as −0.70 eV. To identify the most stable surface, surface energy was calculated for both UN2 and UN1.75 catalyst built in four Miller indices (100), (110), (111), and (121). It was found that (111) surface is the most stable one. Moreover, considering differences in distribution of vacancies in UN1.75, a random vacancy distribution for (111) surface shows the lower surface energy of 0.51 J.m−2. The surface can easily be covered by layer of oxygen at very low oxygen pressure even at high temperature of 1500 K. However, the regeneration of the initial deoxygenated surface is possible under reaction conditions, (N2/H2; 1:3) at 1000 K temperature. Regeneration is further facilitated in the presence of ammonia in the gas mixture.
SN - 1439-4235
SN - 1439-7641
ER -