Method for forming activated alumina coating on refractory article and article thereby produced
AssigneeNissan Motor Co., Ltd.
InventorsTadanari Kato, Tadashi Ikemi, Takatoshi Sagawa
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Abstract
A mixture is prepared by mixing alumina sol and activated alumina which contains not less than 60 Wt % of delta-alumina. The mixture is thereafter coated on a relatively small specific surface area monolithic catalyst carrier. After being dried, the coated carrier is fired to give a high specific surface area catalyst carrier.
Claims16
A method for forming a high surface area coating on the surface of a monolithic catalyst carrier, said method comprising the steps of:
- preparing a mixture containing not more than 20 parts by weight of alumina sol and one part by weight of activated alumina, said alumina sol containing 3 to 15 Wt % of alumina, said activated alumina containing not less than 60 Wt % of delta-alumina;
- coating said mixture onto the surface of the catalyst carrier;
- drying the coated catalyst carrier;
- and
- firing the coated catalyst carrier at a temperature in the range of 150.degree. to 850.degree. C. for a time in the range of from 0.5 to 20 hours to form the high surface area coating on the surface of the catalyst carrier.
A method for preparing a catalyst for purification of a high temperature waste gas, comprising the steps of:
- preparing a mixture containing not more than 20 parts by weight of an alumina sol and one part by weight of activated alumina, said alumina sol containing 3 to 15 Wt% of alumina, said activated alumina containing not less than 60 Wt % of delta-alumina;
- coating said mixture onto the surface of the catalyst carrier;
- drying the coated catalyst carrier;
- firing the coated catalyst carrier at a temperature in the range of 150.degree. to 850.degree. C. for a time in the range of from 0.5 to 20 hours;
- and
- immersing the fired coated catalyst carrier in a solution containing a noble metal.
A method for preparing a catalyst for purification of exhaust gases discharged from automobile engines, said method comprising the steps of:
- preparing a mixture containing not more than 20 parts by weight of an alumina sol and one part by weight of activated alumina, said alumina sol containing 3 to 15 Wt % of alumina, said activated alumina containing not less than 60 Wt % of delta-alumina;
- coating said mixture onto the surface of the catalyst carrier;
- drying the coated catalyst carrier;
- firing the coated catalyst carrier at a temperature in the range of 150.degree. to 850.degree. C. for a time in the range of from 0.5 to 20 hours and
- immersing the fired coated catalyst carrier in a solution containing a noble metal.
A catalyst carrier for carrying a catalytic metal thereon, comprising:
- a monolithic carrier base;
- a high surface area coating formed on the surface of said monolithic carrier base, said high surface area coating is formed by firstly preparing a mixture containing not more than 20 parts by weight of alumina sol and one part by weight of activated alumina, said alumina sol containing 3 to 15 Wt % of alumina said activated alumina containing not less than 60 Wt % of delta-alumina, secondly coating said mixture onto the surface of said monolithic carrier base, thirdly drying the coated carrier base, and lastly firing the coated carrier base at a temperature in the range from 150.degree. to 850.degree. C. for a time in the range of from 0.5 to 20 hours.
A catalyst for purifying exhaust gases from automobile engines, comprising a monolithic carrier, a high surface area coating formed on the surface of said monolithic carrier, said high surface area coating being formed by firstly preparing a mixture containing not more than 20 parts by weight of alumina sol and one part by weight of activated alumina, said alumina sol containing 3 to 15 Wt % of alumina, said activated alumina containing not less than 60 Wt % of delta-alumina, secondary coating said mixture onto the surface of said monolithic carrier, thirdly drying the coated monolithic carrier, fourthly firing the coated catalyst carrier at a temperature in the range of 150.degree. to 850.degree. C. for a time in the range of from 0.5 to 20 hours, and lastly immersing the fired coated monolithic carrier in a solution containing a noble metal.
Dependencies are inferred from the claim text.