| 摘要 |
A catalyst for the removal of carbon monoxide, hydrocarbons and nitrogen oxides in an exhaust gas made by a process comprising: a) preparing a suspension comprising a liquid, a zeolite, a weak base, and salts of copper and silver, said zeolite being crystalline and having a Si/Al atomic ratio between about 5 and about 100, a pore size between about 0.5 nm and about 1.3 nm, essentially no octahedral aluminum detectable by 27Al NMR spectroscopy and a sodium ion exchange capacity, with regard to total aluminum content, greater than 75%, and wherein said suspension contains sufficient amounts of said copper and silver salts to result in a copper content in said catalyst, when finished, between about 0.5 wt. % and about 12 wt. % and a silver content between about 0.25 wt. % and about 20 wt. %; b) adding a sufficient amount of a strong base to raise the pH of the suspension to between about 7 and about 9, thereby creating a metal-containing zeolite support in said suspension; c) separating the support from said liquid; d) dispersing said support on a substrate; and e) drying and calcining the product of step (d).
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