Density Functional Theory Analysis of Elementary Reactions in NOx Reduction on Rh Surfaces and Rh Clusters

Fumiko Deushi, Atsushi Ishikawa, Hiromi Nakai*

*この研究の対応する著者

研究成果: Article査読

12 被引用数 (Scopus)

抄録

The reduction of NOx is crucial for reducing air pollution from vehicle exhaust. In the presence of Rh-based catalysts, the dissociation of NO and the formation of N2O and N2 constitute the important elementary steps of NOx reduction. The present study used density functional theory (DFT) to investigate the catalytic performances of the Rh(111) surface and Rh55 and Rh147 clusters toward these elementary reactions. The NO dissociation reaction was found to have minimum activation barriers (Ea) of 0.63, 0.68, and 1.25 eV on Rh55, Rh147, and Rh(111), respectively. Therefore, it is the fastest on small Rh clusters. In contrast, the N2 formation reaction is relatively inefficient on small clusters, with corresponding Ea values of 2.14, 1.79, and 1.71 eV. Because of the stronger binding of N atoms to the Rh clusters than to the Rh surface, N2 formation through the recombination of N atoms has a higher Ea value on Rh clusters. The calculated reaction rate constants confirmed that small Rh clusters are less reactive for N2 formation than Rh(111), especially at low temperatures. Our results also suggest that N2O formation is largely endothermic and, thus, thermodynamically unfavored. (Figure Presented).

本文言語English
ページ(範囲)15272-15281
ページ数10
ジャーナルJournal of Physical Chemistry C
121
28
DOI
出版ステータスPublished - 2017 7 20

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • エネルギー(全般)
  • 物理化学および理論化学
  • 表面、皮膜および薄膜

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