| 摘要 |
A catalyst and a method for selectively reducing nitrogen oxides with amm onia at low temperatures are provided. The catalyst includes a first compone nt of copper, chromium, cobalt, nickel, manganese, iron, niobium, or mixture s thereof, a second component of cerium, a lanthanide, a mixture of lanthani des, or mixtures thereof, and a zeolite. The catalyst may also include stron tium as an additional second component. The catalyst has high hydrothermal s tability. The catalysts have high activity for conversion of nitrogen oxides in exhaust streams, and are not significantly influenced by the NO/N02 rati o. The catalyst and the method may have special application to selective red uction of nitrogen oxides in exhaust gas from diesel vehicles, as the temper ature of exhaust gas &om diesel vehicles is low, and the exhaust gas gen erally has a high NO/NO2 ratio.
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