IRON AND COPPER-CONTAINING CHABAZITE ZEOLITE CATALYST FOR USE IN NOx REDUCTION

Abstract

A chabazite (CHA) zeolite catalyst containing iron and copper is provided as an SCR catalyst for reducing nitrogen oxides (NOx) from vehicle engine exhausts. The catalyst is formed by incorporating iron during synthesis of the chabazite zeolite, followed by incorporating copper in an ion-exchange step. The resulting catalyst reduces nitrogen oxides over a wide range of temperatures from about 200° C. to about 700° C.

Description

technical field [0001] Embodiments described herein relate to the reduction of nitrogen oxides (NO x ) in the preparation and application of chabazite (CHA) catalysts, and more particularly to the preparation and application of chabazite (CHA) catalysts containing iron and copper therein, which can be used in exhaust systems over a wide temperature range Single SCR catalyst for NOx reduction. Background technique [0002] Catalysts have been used in an attempt to reduce nitrogen oxides (NO x ) emissions. A number of catalysts are currently used to convert these tail gas components into environmentally acceptable compounds. Selective Catalytic Reduction Catalyst (SCR) for NO Conversion x for N 2 And typically include metal-promoted zeolites and utilize an ammonia reductant, typically produced by the thermal decomposition of aqueous urea, which is injected into the exhaust gas stream. Ideally, an SCR catalyst should be able to maintain good catalytic activity over a wide...

AI Technical Summary

Problems solved by technology

This catalyst provides good NO at high temperature x reductive but suffers from other disadvantages

For example, zeolite beta has insufficient thermal stability at high temperatures for sustained prolonged use and tends to absorb large amounts of hydrocarbons, which can lead to exothermic reactions that can damage the catalyst

[0004] While it would be desirable to incorporate metals such as iron into chabazite to achieve both high activity and improved thermal stability, attempts to do so have met with little success

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