| 摘要 |
The present invention relates to sulfur tolerant catalyst composites useful for reducing contaminants in exhaust gas streams, especially gaseous streams containing sulfur oxide contaminants. More specifically, the present invention is concerned with improved NOx trap catalysts for use in diesel engines as well as lean burn gasoline engines. The sulfur tolerant NOx trap catalyst composites comprise a platinum component, a support, and a NOx sorbent component prepared by hydrothermal synthesis. The NOx sorbent component comprises a first metal oxide and a second metal oxide. The metal in the first metal oxide is selected from the group consisting of aluminum, titanium, zirconium, silicon, and composites thereof, and the metal in the second metal oxide is selected from the group consisting of Group IIA metals, Group II metals, Group IV metals, rare earth metals, and transition metals. The metal in the first metal oxide is different from the metal in the second metal oxide. The sulfur tolerant NOx trap catalyst composites are highly effective with a sulfur containing fuel by trapping sulfur oxide contaminants which tend to poison conventional NOx trap catalysts. The sulfur tolerant NOx trap catalyst composites are particularly suitable for diesel engines because the composites can be regenerated at moderate temperatures with rich pulses, rather than at high temperatures.
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