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Mechanistic Insight into Catalytic Oxidation of Ammonia on Clean, O‐ and OH‐Assisted Ir(1 1 1) Surfaces
Author(s) -
Lu Xiaoqing,
Deng Zhigang,
Chau KaShing,
Li Longfei,
Wen Zengqiang,
Guo Wenyue,
Wu ChiMan Lawrence
Publication year - 2013
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201200762
Subject(s) - chemistry , decomposition , catalysis , oxidizing agent , ammonia , inorganic chemistry , selectivity , adsorption , reaction mechanism , organic chemistry
Periodic DFT calculations have been performed to systematically investigate the catalytic mechanisms of ammonia (NH 3 ) decomposition on clean, O‐ and OH‐assisted Ir(1 1 1) surfaces. The adsorption configurations, reaction energies and barriers, and elementary steps were elaborated. Our results show that the NH x ( x =1–3) decomposition prefers to proceed by means of the O‐ and OH‐assisted reaction mechanisms, NH 3 +O→NH 2 +OH, NH 2 +OH→NH+H 2 O, and NH+OH→N+H 2 O, rather than the direct NH x decomposition of NH 3 →NH 2 →NH→N as a result of the high energy barriers involved. The promotion effect of the O‐ and OH‐oxidizing agents are then discussed using energy barrier analysis. The relationships between the selectivity toward the final product and coverage, O to N coverage, and reaction temperature are elucidated. Finally, we compare our results with analogous investigations of NH 3 decomposition on Pt, Rh, and Ir surfaces.