METHOD FOR FORMING CATALYTIC NANOCOATING

Abstract

Provided is a method forming a catalytic nanocoating on a surface of a metal plate, wherein the method comprises pretreating the surface of the metal plate by means of heat treatment at 500-800° C., forming a metaloxide support by washcoating on the surface of the metal plate, and coating the surface of the metal plate by depositing catalytically active metals and/or metaloxides on the metaloxide support by means of an atomic layer deposition (ALD) method in order to form a thin and conformal catalyst layer on the metal plate. Further, the invention relates to a catalyst and a use.

Claims

1. A method for forming a catalytic nanocoating on a surface of a metal plate, wherein the method comprises pretreating the surface of the metal plate by means of heat treatment at 500-800° C., forming a metaloxide support by washcoating on the surface of the metal plate, and coating the surface of the metal plate by depositing catalytically active metals and/or metaloxides on the metaloxide support by means of an atomic layer deposition (ALD) method in order to form a thin and conformal catalyst layer on the metal plate.

2. The method according to claim 1, wherein the surface of the metal plate is heat-treated by oxidizing.

3. The method according to claim 1, wherein the surface of the metal plate is washcoated with a metaloxide based slurry.

4. The method according to claim 1, wherein the washcoating is carried out by spraying or dip-coating.

5. The method according to claim 1, wherein the metaloxide support is calcined at 500-800° C. after the washcoating.

6. The method according to claim 1, wherein catalytically active metals and/or metaloxides are deposited at 50-700° C. on the metaloxide support by means of an atomic layer deposition (ALD) method.

7. The method according to claim 1, wherein the thickness of the catalyst layer is between 1-500 nm.

8. The method according to claim 1, wherein tris(2,2,6,6-tetramethyl-3,5-heptanedionato)cobalt and ozone are used as precursors in the atomic layer deposition (ALD).

9. The method according to claim 1, wherein the metaloxide support comprises Al.sub.2O.sub.3, MgO, TiO.sub.2, other metaloxide or their combination.

10. The method according to claim 1, wherein catalytically active metal and/or metaloxide comprises metal selected from the group Co, Ni, Mo, Zr, Ti, Hf, noble metal, other suitable metal and their combinations.

11. A catalyst, wherein the catalyst comprises a catalytic nanocoating on the surface of the metal plate, and the catalytic nanocoating has been formed onto the surface of the metal plate by the method of claim 1.

12. A catalyst according to claim 11, wherein the catalyst is used in catalytic reactors, in self-cleaning surfaces, in production of biomass derived chemicals, in production of transportation fuels, in FT-synthesis, in reformers for fuel cell applications, in gas treatment units for syngas applications or in aqueous phase reformers for biorefineries.

13. A use of the method of claim 1, wherein the method is used to form a catalytic nanocoating into reactors, such as catalytic reactors, reformers of fuel cell applications and aqueous phase reformers for biorefinery, and in processes, such as production of biomass derived chemicals, production of transportation fuels, FT-synthesis and gas treatment unit for syngas applications and production of self-cleaning surfaces, and their combinations.

Description

LIST OF FIGURES

[0030] In the following section, the invention will be described with the aid of detailed exemplary embodiments, referring to the accompanying drawing wherein

[0031] FIG. 1 presents a flowchart illustration of a method according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0032] FIG. 1 presents the method according to the invention for forming a catalytic nanocoating.

EXAMPLE 1

[0033] In the method of FIG. 1 a catalytic nanocoating is formed on a surface of a metal plate.

[0034] The surface of the metal plate is pretreated (1) by means of heat treatment by oxidizing at 500-800° C. The metaloxide support, such as Al.sub.2O.sub.3 support, is formed by washcoating (2) on the pretreated metal surface so that the metal surface is washcoated with metaloxide based slurry, such as Al.sub.2O.sub.3 based slurry, by spraying or dip-coating. The washcoated support is calcined (3) at 500-800° C. on the metal surface. The catalytically active metals and/or metaloxides, such as Co oxide, are deposited (4) by means of an atomic layer deposition (ALD) method on the metal surface which has been coated with the metaloxide support. The catalytically active metals and/or metaloxides are deposited at temperature between 140 to 300° C. on the metaloxide support. Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)cobalt and ozone are used as precursors in the ALD process. Nitrogen is used as a carrier and purging gas. Depending on the number of cycles a catalyst layer which has a thickness between 1-500 nm is formed on the metaloxide support.

[0035] The metals and/or metaloxides can be homogeneously dispersed on the metaloxide support, and at high temperature they are also well adhered on the surface.

[0036] The devices used in example 1 and this invention are known per se, and therefore they are not described in any more detail in this context.

EXAMPLE 2

[0037] In this test process conditions were studied.

[0038] Picosun Sunale R-200 ALD reactor was used for deposition of CoO.sub.x in single wafer mode. Co(thd)3 i.e. tris(2,2,6,6-tetramethyl-3,5-heptanedionato)cobalt (abcr GmbH & Co. KG, purity 99%) and ozone (O3) (O2 99.999% purity, AC-SERIES ozone generator, IN USA, Inc.) were used as precursors. Nitrogen (99.999%) was used as a carrier and purging gas.

[0039] Different deposition temperatures, precursor temperatures, pulse and purge times and line flows were tested in order to find the best parameters for the film growth. After optimizing deposition parameters CoO.sub.x depositions were performed at about 150° C. Film thicknesses on Si reference substrates were measured by ellipsometer (SE400adv, SENTECH Instruments). Deposition rate was around 0.2 Å/cycle at 150° C. After ALD deposition catalytic activity was evaluated by existing methods. It was observed that catalytic activity was achieved.

[0040] The method according to the invention is suitable in different embodiments for forming different catalytic nanocoatings. The method according to the invention is suitable in different embodiments for forming different kinds of catalysts.

[0041] The invention is not limited merely to the examples referred to above; instead many variations are possible within the scope of the inventive idea defined by the claims.