Structured selective catalytic reduction-catalyst, useful for removing nitrogen oxide in exhaust gas, comprises catalytically active material zones of iron-exchanged zeolite and transition metal-exchanged zeolite

摘要

Structured selective catalytic reduction (SCR)-catalyst, for the removal of nitrogen oxide in the exhaust gas of combustion motors using ammonia or ammonia decomposable compound as reducing agents, comprises several catalytically active material zones, which are optionally applied with a catalytically inert supporting body and are contacted by the exhaust fumes temporally after each other. Structured selective catalytic reduction (SCR)-catalyst, for the removal of nitrogen oxide in the exhaust gas of combustion motors using ammonia or ammonia decomposable compound as reducing agents, comprises several catalytically active material zones, which are optionally applied with a catalytically inert supporting body and are contacted by the exhaust fumes temporally after each other; where the material zone is characterized by different turnover sections of the SCR-reaction, the turnover sections of the material zone contacted first by the exhaust gas that can be cleaned lies at higher temperature than the turnover profile of the material zone, the zone contacted first by the exhaust gas that can be cleaned contains iron-exchanged zeolites, and the material zone contacted by the material zone contains transition metal exchanged zeolite or a transition metal oxide such as vanadium pentoxide, tungsten trioxide and/or titanium dioxide. An independent claim is included for a recycling plant containing the structured SCR-catalyst.