| 摘要 |
The present invention generally relates to supported perovskites of the formula XYO3 where X is lanthanum, cerium or yttrium and Y is a transition metal such as copper, chromium, manganese, iron, cobalt and nickel supported on a support such as alumina, silica, magnesium aluminate, titanium oxide, zirconium oxide and mixtures thereof. In the case where X is lanthanum, some of the lanthanum ions may be replaced resulting in a perovskite of the formula La1-xAxYO3 wherein x is about 0.75 or less and A is silver or magnesium and Y is manganese or iron. Their use for low temperature oxidation of volatile organic compounds (VOCs), particularly oxygen-containing VOCs. The support may be stabilized by having an intermediate metal oxide layer on the surface of the support wherein the metal of the intermediate metal oxide may be iron, magnesium, cobalt, nickel, manganese, zinc, titanium, copper, chromium, lanthanum, barium, calcium, strontium or silver. The catalysts contain platinum or palladium. The present invention further relates to the use of supported perovskites to reduce the amount of VOCs present in waste gases produced by processes such as baking, brewing, and flexographic printing. Catalysts prepared from the supported perovskites have increased resistance to poisoning in the presence of sulfur containing compounds.
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