Patent ID: 6127300
Filing Date: 2000-10-03
Classification: B01D,B01J,Y02A,Y02T

Abstract:
A process for making a catalyst containing at least one type of molecular sieve crystals having noble metal dispersed on the exterior surface of said molecular sieve crystals such that at least 90% of the noble metal is located within 500 .ANG. of the exterior surface of said molecular sieve crystals comprising:a) preparing an aqueous suspension of at least one type of molecular sieve crystals and a noble metal reagent, said reagent being of the type that, when suspended in water, will chemisorb onto the exterior 500 .ANG. of said crystals;b) adjusting the pH of the suspension to above about 7 with a material that will decompose to yield gaseous products when its temperature is raised to above about 150.degree. C.;c) stirring the suspension until the molecular sieve crystals and reagent are thoroughly mixed and the chemisorption has taken place;d) coating a suitable substrate with the product of step (c) thereby preparing a coated substrate having a coating thickness between 1-20 microns;e) drying the coated substrate, and, thereafter,f) calcining said coated substrate at a temperature between about 400.degree. C. to about 550.degree. C. for at least two hours.