FIELD: chemistry.
SUBSTANCE: invention relates to a catalyst for selective catalytic reduction (SCR). Catalyst comprises one or more zeolites of MFI structure type and one or more SNA structure type zeolites. Wherein at least a portion of one or more zeolites of MFI structure type contains iron (Fe), and at least a portion of one or more SNA structure type zeolites contains copper (Cu). Present invention also relates to a catalytic article comprising a catalyst, an exhaust gas treatment system comprising a catalyst and a process for treating a gas stream comprising passing said gas stream through the catalyst.
EFFECT: catalyst has higher overall conversion of NOx into elementary nitrogen, at the same or lower breakthrough of NH3, than any molecular sieve component taken separately, when total molar ratio of NO: NO2 in feed gas entering catalyst is equal to or less than 1.
17 cl, 14 dwg, 3 tbl, 8 ex
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