NO + H2 reaction over Pd(110): TPD, TPR and DFT study

Anna A. Bryliakova, Andrey V. Matveev, Vladimir M. Tapilin, Vladimir V. Gorodetskii

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    1 Citation (Scopus)

    Abstract

    Temperature-programming desorption (TPD) and temperature-programmed reaction (TPR) have been applied to study the reduction of 15NO by deuterium on a Pd(110) surface. TPR results show that the reaction occurs in the autocatalytic regime of surface explosion with the rate-limiting step of 15NOads dissociation into highly reactive Oads and 15Nads atoms. The steady-state reaction leads to formation of 15N2, D2O, 15ND3 and 15N2O products. The phenomena of a reaction rate hysteresis observed during a heating-cooling cycle can be attributed to accumulation of 15NOads at low temperatures followed by surface explosion at T ∼ 490 K. The binding energies and structural parameters of species involved in the NO + H2 reaction over Pd(110) have been calculated by the DFT technique, and plausible reaction pathways have been considered. NO dissociation from the most stable short bridge site (Eb = −1.94 eV) occurs via the intermediates in on-top and long bridge modes with lower binding energy (Eb = −1.31 to 1.65 eV). The energy of transition states reaches 0.2–0.26 eV over energy of NO in a gas phase, which confirms the rate-limiting role of NO dissociation. It has been demonstrated that OHads-group formation is the rate-limiting step of water molecule generation. Subsequent H2O formation occurs via disproportionation of the OHads intermediates.

    Original languageEnglish
    Pages (from-to)53-62
    Number of pages10
    JournalMolecular Catalysis
    Volume448
    DOIs
    Publication statusPublished - 1 Apr 2018

    Keywords

    • DFT
    • NO dissociation
    • NO reduction
    • Palladium
    • Surface chemical reactions
    • PD(110) SURFACE
    • ELASTIC BAND METHOD
    • DISSOCIATIVE ADSORPTION
    • CO OXIDATION
    • OSCILLATORY BEHAVIOR
    • PD SURFACES
    • MINIMUM ENERGY PATHS
    • SADDLE-POINTS
    • NITRIC-OXIDE
    • DESORBING PRODUCTS

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