Determination of active palladium species in ZSM-5 zeolite for selective reduction of nitric oxide with methane

Masaru Ogura, Masayoshi Hayashi, Susumu Kage, Masahiko Matsukata, Eiichi Kikuchi

    Research output: Contribution to journalArticle

    46 Citations (Scopus)

    Abstract

    The active site in ZSM-5 zeolite-supported palladium, which shows the catalytic activity for NO reduction with methane as a reducing agent, has been investigated qualitatively and quantitatively by means of NO chemisorption and NaCl titration, comparing with PdO supported on silica. Palladium species in 0.4 wt.% Pd loaded H-ZSM-5 can adsorb NO equimolarly after calcination at 773 K, and almost all the NO was desorbed at around 673 K, while the palladium species on PdO/SiO2 hardly adsorbed NO. The palladium species in Pd(0.4)/H-ZSM-5 are ion-exchangeable with Na+ in NaCl solution, indicating that they exist in a cationic state of an isolated Pd2+. This method for quantitative analysis of the isolated Pd2+ cations is named as 'NaCl titration'. The amount of the isolated Pd2+ cationic species increased with increasing palladium content on Pd/H-ZSM-5, and PdO co-existed above 1 wt.%. The amount of the isolated Pd2+ cation was unchanged after the reaction of NO2-CH4, NO2-CH4-O2, or CH4-O2 at 673 K, while the adsorbed amount of NO per the Pd2+ as determined by NO-TPD decreased after the NO2-CH4-O2 reaction. It was found by NaCl titration that the catalytic activity of Pd/H-ZSM-5 for NO2-CH4-O2 reaction increased with increasing amount of the isolated Pd2+ cationic species up to 0.7 wt.%, while the increase in the amount of PdO led to decrease in selectivity towards NO2 reduction. The palladium species that are active and selective for NO reduction with CH4 will be proposed.

    Original languageEnglish
    Pages (from-to)247-257
    Number of pages11
    JournalApplied Catalysis B: Environmental
    Volume23
    Issue number4
    DOIs
    Publication statusPublished - 1999 Dec 6

    Fingerprint

    Methane
    Nitric oxide
    palladium
    Palladium
    nitric oxide
    zeolite
    Nitric Oxide
    methane
    Titration
    Cations
    Catalyst activity
    cation
    Positive ions
    Reducing Agents
    Reducing agents
    Temperature programmed desorption
    Chemisorption
    Silicon Dioxide
    Calcination
    quantitative analysis

    Keywords

    • Methane
    • NaCl titration
    • NO reduction
    • NO-TPD
    • Palladium

    ASJC Scopus subject areas

    • Catalysis
    • Process Chemistry and Technology
    • Environmental Chemistry

    Cite this

    Determination of active palladium species in ZSM-5 zeolite for selective reduction of nitric oxide with methane. / Ogura, Masaru; Hayashi, Masayoshi; Kage, Susumu; Matsukata, Masahiko; Kikuchi, Eiichi.

    In: Applied Catalysis B: Environmental, Vol. 23, No. 4, 06.12.1999, p. 247-257.

    Research output: Contribution to journalArticle

    Ogura, Masaru ; Hayashi, Masayoshi ; Kage, Susumu ; Matsukata, Masahiko ; Kikuchi, Eiichi. / Determination of active palladium species in ZSM-5 zeolite for selective reduction of nitric oxide with methane. In: Applied Catalysis B: Environmental. 1999 ; Vol. 23, No. 4. pp. 247-257.
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    abstract = "The active site in ZSM-5 zeolite-supported palladium, which shows the catalytic activity for NO reduction with methane as a reducing agent, has been investigated qualitatively and quantitatively by means of NO chemisorption and NaCl titration, comparing with PdO supported on silica. Palladium species in 0.4 wt.{\%} Pd loaded H-ZSM-5 can adsorb NO equimolarly after calcination at 773 K, and almost all the NO was desorbed at around 673 K, while the palladium species on PdO/SiO2 hardly adsorbed NO. The palladium species in Pd(0.4)/H-ZSM-5 are ion-exchangeable with Na+ in NaCl solution, indicating that they exist in a cationic state of an isolated Pd2+. This method for quantitative analysis of the isolated Pd2+ cations is named as 'NaCl titration'. The amount of the isolated Pd2+ cationic species increased with increasing palladium content on Pd/H-ZSM-5, and PdO co-existed above 1 wt.{\%}. The amount of the isolated Pd2+ cation was unchanged after the reaction of NO2-CH4, NO2-CH4-O2, or CH4-O2 at 673 K, while the adsorbed amount of NO per the Pd2+ as determined by NO-TPD decreased after the NO2-CH4-O2 reaction. It was found by NaCl titration that the catalytic activity of Pd/H-ZSM-5 for NO2-CH4-O2 reaction increased with increasing amount of the isolated Pd2+ cationic species up to 0.7 wt.{\%}, while the increase in the amount of PdO led to decrease in selectivity towards NO2 reduction. The palladium species that are active and selective for NO reduction with CH4 will be proposed.",
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    AU - Ogura, Masaru

    AU - Hayashi, Masayoshi

    AU - Kage, Susumu

    AU - Matsukata, Masahiko

    AU - Kikuchi, Eiichi

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    AB - The active site in ZSM-5 zeolite-supported palladium, which shows the catalytic activity for NO reduction with methane as a reducing agent, has been investigated qualitatively and quantitatively by means of NO chemisorption and NaCl titration, comparing with PdO supported on silica. Palladium species in 0.4 wt.% Pd loaded H-ZSM-5 can adsorb NO equimolarly after calcination at 773 K, and almost all the NO was desorbed at around 673 K, while the palladium species on PdO/SiO2 hardly adsorbed NO. The palladium species in Pd(0.4)/H-ZSM-5 are ion-exchangeable with Na+ in NaCl solution, indicating that they exist in a cationic state of an isolated Pd2+. This method for quantitative analysis of the isolated Pd2+ cations is named as 'NaCl titration'. The amount of the isolated Pd2+ cationic species increased with increasing palladium content on Pd/H-ZSM-5, and PdO co-existed above 1 wt.%. The amount of the isolated Pd2+ cation was unchanged after the reaction of NO2-CH4, NO2-CH4-O2, or CH4-O2 at 673 K, while the adsorbed amount of NO per the Pd2+ as determined by NO-TPD decreased after the NO2-CH4-O2 reaction. It was found by NaCl titration that the catalytic activity of Pd/H-ZSM-5 for NO2-CH4-O2 reaction increased with increasing amount of the isolated Pd2+ cationic species up to 0.7 wt.%, while the increase in the amount of PdO led to decrease in selectivity towards NO2 reduction. The palladium species that are active and selective for NO reduction with CH4 will be proposed.

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