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

Fumiko Deushi, Atsushi Ishikawa, Hiromi Nakai

    Research output: Contribution to journalArticle

    5 Citations (Scopus)

    Abstract

    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).

    Original languageEnglish
    Pages (from-to)15272-15281
    Number of pages10
    JournalJournal of Physical Chemistry C
    Volume121
    Issue number28
    DOIs
    Publication statusPublished - 2017 Jul 20

    Fingerprint

    Density functional theory
    density functional theory
    Atoms
    Air pollution
    Reaction rates
    Rate constants
    Chemical activation
    Catalysts
    dissociation
    air pollution
    Temperature
    atoms
    vehicles
    reaction kinetics
    activation
    catalysts

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Energy(all)
    • Physical and Theoretical Chemistry
    • Surfaces, Coatings and Films

    Cite this

    Density Functional Theory Analysis of Elementary Reactions in NOx Reduction on Rh Surfaces and Rh Clusters. / Deushi, Fumiko; Ishikawa, Atsushi; Nakai, Hiromi.

    In: Journal of Physical Chemistry C, Vol. 121, No. 28, 20.07.2017, p. 15272-15281.

    Research output: Contribution to journalArticle

    @article{03de148e289e49fc8c0d4d44fdca123f,
    title = "Density Functional Theory Analysis of Elementary Reactions in NOx Reduction on Rh Surfaces and Rh Clusters",
    abstract = "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).",
    author = "Fumiko Deushi and Atsushi Ishikawa and Hiromi Nakai",
    year = "2017",
    month = "7",
    day = "20",
    doi = "10.1021/acs.jpcc.7b04526",
    language = "English",
    volume = "121",
    pages = "15272--15281",
    journal = "Journal of Physical Chemistry C",
    issn = "1932-7447",
    publisher = "American Chemical Society",
    number = "28",

    }

    TY - JOUR

    T1 - Density Functional Theory Analysis of Elementary Reactions in NOx Reduction on Rh Surfaces and Rh Clusters

    AU - Deushi, Fumiko

    AU - Ishikawa, Atsushi

    AU - Nakai, Hiromi

    PY - 2017/7/20

    Y1 - 2017/7/20

    N2 - 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).

    AB - 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).

    UR - http://www.scopus.com/inward/record.url?scp=85025455084&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=85025455084&partnerID=8YFLogxK

    U2 - 10.1021/acs.jpcc.7b04526

    DO - 10.1021/acs.jpcc.7b04526

    M3 - Article

    AN - SCOPUS:85025455084

    VL - 121

    SP - 15272

    EP - 15281

    JO - Journal of Physical Chemistry C

    JF - Journal of Physical Chemistry C

    SN - 1932-7447

    IS - 28

    ER -