Catalyst for reducing oxides of nitrogen in the exhaust gas from internal combustion engines and process for making the catalyst

Claim 2

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides being those of one or more members selected from the group consisting of copper, nickel, iron, and chromium, and said catalyst being prepared by the method consisting of the steps of: (a) plating the surface of said support or substrate with one or more layers of one or more of said members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 3

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said support or substrate being a stainless steel or an alloy comprising nickel, iron, and chromium and containing one or more members of the group consisting of copper, vanadium, titanium, manganese, molybdenum, aluminum, tungsten, and chromium, and said oxides being those of one or more members selected from the group consisting of copper, nickel, iron, and chromium, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with one or more layers of one or more of said members selected from the group consisting of copper, nickel, iron, and chromium to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members selected from the group consisting of copper, nickel, iron, and chromium interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members selected from the group consisting of copper, nickel, iron, and chromium.

Claim 4

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said support or substrate being a stainless steel or an alloy comprising nickel, iron, and chromium and containing one or more members of the group consisting of copper, vanadium, titanium, manganese, molybdenum, aluminum, tungsten, and chromium, and said oxides being those of one or more members selected from the group consisting of copper, nickel, iron, and chromium, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with one or more layers of one or more of said members selected from the group consisting of copper, nickel, iron, and chromium to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members selected from the group consisting of copper, nickel, iron, and chromium interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members selected from the group consisting of copper, nickel, iron, and chromium.

Claim 5

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides being the oxides of the members of the group consisting of copper, nickel, chromium, and iron, said support or substrate being an alloy comprising nickel, iron, and chromium, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with one or more layers of said members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 6

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides being the oxides of the members of the group consisting of copper, nickel, chromium, and iron, said support or substrate being an alloy comprising nickel, iron, and chromium, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with one or more layers of said members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 7

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides comprising the oxides of chromium and the oxides of one or more members selected from the group consisting of copper, nickel, and iron, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with layers of said chromium and members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said chromium and members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said chromium and members.

Claim 8

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides comprising the oxides of chromium and the oxides of one or more members selected from the group consisting of copper, nickel, and iron, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with layers of said chromium and members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said chromium and members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said chromium and members.

Claim 9

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides being the oxides of the members of the group consisting of copper, nickel, chromium, and iron, said support or substrate being a support or substrate of a stainless steel or an alloy comprising nickel, iron, and chromium, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with one or more layers of said members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 10

A catalyst for catalytically reducing the oxides of nitrogen in the exhaust gases from an internal combustion engine, which catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000° F., said oxides being the oxides of the members of the group consisting of copper, nickel, chromium, and iron, said support or substrate being a support or substrate of a stainless steel or an alloy comprising nickel, iron, and chromium, and said catalyst being prepared by the method comprising the steps of: (a) plating the surface of said support or substrate with one or more layers of said members to form a plated support or substrate, (b) heating in an inert atmosphere said plated support or substrate so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (c) exposing said plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 11

A process for making a catalyst for reducing oxides of nitrogen, which process consists of the steps of: (a) heating in an inert atmosphere a support or substrate plated with one or more thin layers of one or more members selected from the group consisting of copper, nickel, iron, and chromium so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (b) exposing said support or substrate plated with said layers of said members to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 12

A process for making a catalyst for reducing oxides of nitrogen, which process consists of the steps of: (a) heating in an inert atmosphere a support or substrate plated with one or more thin layers of one or more members selected from the group consisting of copper, nickel, iron, and chromium so that the atoms on the surfaces of said members interdiffuse with themselves and with surface atoms of said support or substrate, and (b) exposing said support or substrate plated with said layers of said members to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said plated support or substrate to form thereat oxides of said members.

Claim 13

A process for making a catalyst for reducing oxides of nitrogen, which process comprises the steps of: (a) heating in an inert atmosphere a metal substrate plated with a thin layer of copper or thin layers of copper and nickel so that the atoms in the layer or layers interdiffuse with themselves and with the atoms of the substrate to form a surface of mixed metals, and (b) exposing said surface of mixed metals to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said mixed metals to form thereat oxides of said mixed metals.

Claim 14

A process for making a catalyst for reducing oxides of nitrogen, which process comprises the steps of: (a) heating in an inert atmosphere a metal substrate plated with a thin layer of copper or thin layers of copper and nickel so that the atoms in the layer or layers interdiffuse with themselves and with the atoms of the substrate to form a surface of mixed metals, and (b) exposing said surface of mixed metals to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of said mixed metals to form thereat oxides of said mixed metals.

Claim 15

The process of claim 7 wherein the heating step is conducted at temperatures in excess of about 1,400° F.

Claim 16

The process of claim 7 wherein the inert atmosphere is nitrogen, carbon dioxide, helium, or argon.

Claim 17

The process of claim 7 wherein the oxidation of said surface of mixed metals is conducted in an oxygen-containing atmosphere.

Claim 18

The process of claim 7 wherein the oxidation of said surface of mixed metals is accomplished by exposing said surface of mixed metals to an exhaust from an internal combustion engine operated under lean-fuel conditions and including at least about 1.5 volume percent oxygen.

Claim 19

The process of claim 7 wherein said substrate comprises iron and wherein sufficient copper is present on the surface of the substrate so that the ratio of iron to copper in the oxides formed at or near the surface is about 1:1.

Claim 20

The process of claim 10 wherein the oxygen-containing-atmosphere includes moisture.

Claim 21

The process of claim 8 wherein the inert atmosphere is nitrogen, carbon dioxide, helium, or argon.

Claim 22

The process of claim 8 wherein the oxidation of said surface of mixed metals is conducted in an oxygen-containing atmosphere.

Claim 23

The process of claim 8 wherein the oxidation of said surface of mixed metals is accomplished by exposing said surface of mixed metals to an exhaust from an internal combustion engine operated under lean-fuel conditions and including at least about 1.5 volume percent oxygen.

Claim 24

The process of claim 8 wherein said substrate comprises iron and wherein sufficient copper is present on the surface of the substrate so that the ratio of iron to copper in the oxides formed at or near the surface is about 1:1.

Claim 25

The process of claim 15 wherein the oxygen-containing atmosphere includes moisture.