초록

A catalyst for the removal of carbon monoxide, hydrocarbons and nitrogen oxides in an exhaust gas made by a process comprising:

대표청구항 ▼

[ I claim:] [1.] 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 atom

[ I claim:] [1.] 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 .sup.27 Al 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. %, a silver content between about 0.25 wt. % and about 20 wt. %, an atomic ratio of copper to aluminum greater than 0.5, and an atomic ratio of copper to silver greater than 1.0;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; ande) drying and calcining the product of step (d).