Catalytic conversion of CO, NO and SO 2 on supported sulfide catalysts II. Catalytic reduction of NO and SO 2 by CO

S. X. Zhuang, M. Yamazaki, K. Omata, Yasufumi Takahashi, M. Yamada

    Research output: Contribution to journalArticlepeer-review

    35 Citations (Scopus)

    Abstract

    To investigate the possibility of simultaneous catalytic reduction of NO and SO 2 by CO, reactions of NO, NO-CO, and NO-SO 2 -CO were performed on γ-alumina-supported sulfides of transition metals including Co, Mo, CoMo and FeMo. NO was decomposed into N 2 O and N 2 accompanied with the formation of SO 2 ; this serious oxidation of lattice sulfur resulted in the deactivation of the catalysts. The addition of CO to the NO stream suppressed SO 2 formation and yielded COS instead. A stoichiometric conversion of NO and CO to N 2 and CO 2 was observed above 350°C on the CoMo and the FeMo catalysts. Although the CO addition lengthened catalyst life, it was not enough to maintain activity. After the NO-CO reaction, an XPS analysis showed the growth of Mo 6+ and SO 4 2- peaks, especially for the sulfided FeMo/Al 2 O 3 ; the FeMo catalyst underwent strong oxidation in the NO-CO reaction. The NO and the NO-CO reactions proceeded non-catalytically, consuming catalyst lattice sulfur to yield SO 2 or COS. The addition of SO 2 in the NO - CO system enabled in situ regeneration of the catalysts; the catalysts oxidized through abstraction of lattice sulfur experienced anew reduction and sulfurization through the SO 2 -CO reaction at higher temperature. NO and SO 2 were completely and catalytically converted at 400°C on the sulfided CoMo/Al 2 O 3 . By contrast, the sulfided FeMo/Al 2 O 3 was easily oxidized by NO and hardly re-sulfided under the test conditions. Oxidation states of the metals before and after the reactions were determined. Silica and titania-supported CoMo catalysts were also evaluated to study support effects.

    Original languageEnglish
    Pages (from-to)133-143
    Number of pages11
    JournalApplied Catalysis B: Environmental
    Volume31
    Issue number2
    DOIs
    Publication statusPublished - 2001 May 4

    Keywords

    • CO
    • Catalytic reduction
    • Cobalt molybdenum catalyst
    • NO
    • SO
    • Sulfide catalysts

    ASJC Scopus subject areas

    • Catalysis
    • Environmental Science(all)
    • Process Chemistry and Technology

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