Theoretical Study on the Catalytic Reduction Mechanism of NO by CO on Tetrahedral Rh4 Subnanocluster

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• 作者：Hua-Qing Yang ; Hong-Quan Fu ; Ben-Fang Su ; Bo Xiang ; Qian-Qian Xu ; Chang-Wei Hu
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：119
• 期：47
• 页码：11548-11564
• 全文大小：1141K
• ISSN：1520-5215

文摘

The catalytic mechanism of 2NO + 2CO 鈫?N₂ + 2CO₂ on Rh₄ cluster has been systematically investigated on the ground and first excited states at the B3LYP/6-311+G(2d),SDD level. For the overall reaction of 2NO + 2CO 鈫?N₂ + 2CO₂, the main reaction pathways take place on the facet site rather than the edge site of the Rh₄ cluster. The turnover frequency (TOF) determining transition states are characteristic of the second N鈥揙 bond cleavage with rate constant k₄ = 1.403 脳 10¹¹ exp (鈭?81鈥?03/RT) and the N鈥揘 bond formation for the intermediate N₂O formation with rate constant k₂ = 3.762 脳 10¹² exp (鈭?07鈥?17/RT). The TOF-determining intermediates of ³N_bRh₄NO and ³N_bRh₄O_b(NO) are associated with the nitrogen-atom molecular complex, which is in agreement with the experimental observation of surface nitrogen. On the facet site of Rh₄ cluster, the formation of CO₂ stems solely from the recombination of CO and O atom, while N₂ originates partly from the recombination of two N atoms and partly from the decomposition of N₂O. For the N鈥揙 bond cleavage or the synchronous N鈥揙 bond cleavage and C鈥揙 bond formation, the neutral Rh₄ cluster exhibits better catalytic performance than the cationic Rh₄⁺ cluster. Alternatively, for N鈥揘 bond formation, the cationic Rh₄⁺ cluster possesses better catalytic performance than the neutral Rh₄ cluster.