Catalytic process
AssigneeImperial Chemical Industries PLC
InventorsJohn Stewart Campbell, Keith Farmery, David John Heath, Norman Henry Harbord
Life of this patent
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Abstract
In a supported catalyst for treating internal combustion engine exhaust gases the active material comprises a non-noble metal or compound thereof and the support comprises a primary support carrying a secondary support; the secondary support consists essentially of one or more involatile acidic and/or amphoteric oxides substantially in combination with one or more basic oxides from Group II, III or IV of the Periodic Table. A platinum group metal may also be present. The catalyst can be used for reductive or oxidative treatment or for simultaneous reduction of nitrogen oxides and oxidation of carbon monoxide and hydrocarbons and exhibits high activity and long life.
Claims18
A catalyst for treating internal combustion engine exhaust gases which comprises at least one non-noble metal or compound thereof on a support that comprises a primary catalyst support carrying a refractory secondary catalyst support, the secondary support consisting essentially of one or more involatile acidic and/or amphoteric oxides selected from the group consisting of alumina, silica, chromia, manganese oxide, iron oxide and mixtures or compounds thereof substantially in combination with one or more basic oxides from the group consisting of calcium, strontium and barium wherein at least 70% by weight of said acidic and/or amphoteric oxide is in combination with said basic oxides and said one or more basic oxides is present in a quantity that will give a stoichiometric compound with said acidic and/or amphoteric compound.
A method of producing a catalyst of at least one non-noble metal or compound thereof on a support which comprises a primary catalyst support carrying a refractory secondary catalyst support, the secondary support consisting essentially of one or more involatile acidic and/or amphoteric oxides selected from the group consisting of alumina, silica, chromia, manganese oxide, iron oxide and mixtures or compounds thereof substantially in combination with one or more basic oxides from the group consisting of calcium, strontium and barium which comprises the step of reacting secondary support precursor compounds together at an elevated temperature of over 800.degree.C in the presence of a compound thermally decomposable to form a highly porous solid.
Dependencies are inferred from the claim text.