Process for making a lead-tolerant catalyst system for purifying exhaust
AssigneeJohnson Matthey Public Limited Company
InventorsBrian Harrison, Alan F. Diwell
Life of this patent
Estimating the term…
Abstract
A process for improving the lead tolerance of a motor vehicle exhaust purification catalyst system of the type comprising a platinum group metal catalyst carried on alumina. The improvement derives from impregnating the alumina with barium moiety and firing at at least 400.degree. C. before subsequent impregnation with the metal catalyst moiety.
Claims5
A process for making a lead tolerant catalyst system comprising a catalyst consisting essentially of platinum group metal carried on supported alumina having a surface area of at least 50 m.sup.2 /g which process comprises impregnating the supported alumina with a solution of a barium compound, subjecting the alumina to an intermediate firing at a temperature of at least 400.degree. C., subsequently impregnating the alumina with a solution of a compound selected from the group consisting of compounds of platinum, palladium and rhodium and then subjecting the alumina to a firing at a temperature of at least 400.degree. C.
Dependencies are inferred from the claim text.