Method for the production of electrocatalyst powders

• US 20030013606A1
• Filed: 08/01/2002
• Published: 01/16/2003
• Est. Priority Date: 02/24/1998
• Status: Active Grant

• Current Assignee: Cabot Corporation
• Original Assignee: Cabot Corporation
• Inventors: Kunze, Klaus, Atanassova, Paolina, Hampden-Smith, Mark J., Kodas, Toivo T., Dericotte, David, Atanassov, Plamen, Napolitano, Paul
• Granted Patent: US 7,066,976 B2
• Time in Patent Office: Days
• US Class Current: 502/180
• CPC Class Codes: B01J 13/02 Making microcapsules or microballoons for medical preparations A61K9/50
• CPC Class Codes: B01J 19/10 employing sonic or ultrasonic vibrations
• CPC Class Codes: B01J 19/2405 provoking a turbulent flow of the reactants, such as in cyclones, or having a high Reynolds-number
• CPC Class Codes: B01J 2/02 by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B01J 2219/00112 involving reactant solids
• CPC Class Codes: B01J 2219/00155 using insulating materials or refractories
• CPC Class Codes: B01J 2219/00159 controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
• CPC Class Codes: B01J 2219/00162 controlling the pressure
• CPC Class Codes: B01J 2219/00166 controlling the residence time inside the reactor vessel
• CPC Class Codes: B01J 2219/00171 controlling the density
• CPC Class Codes: B01J 2219/00186 controlling the composition of the reactive mixture
• CPC Class Codes: B01J 23/00 Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 B01J21/16 takes precedence
• CPC Class Codes: B01J 23/34 Manganese
• CPC Class Codes: B01J 23/40 of the platinum group metals
• CPC Class Codes: B01J 31/06 containing polymers organometallic polymers B01J31/123; polymer-bound organometallic complexes B01J31/165; coordination polymers B01J31/1691
• CPC Class Codes: B01J 35/002 Catalysts characterised by their physical properties
• CPC Class Codes: B01J 35/0033 Electric or magnetic properties
• CPC Class Codes: B01J 35/006 metal crystallite size
• CPC Class Codes: B01J 35/023 Catalysts characterised by dimensions, e.g. grain size
• CPC Class Codes: B01J 35/08 : Spheres
• CPC Class Codes: B01J 35/1014 : 10-100 m2/g
• CPC Class Codes: B01J 35/30 : characterised by their physical properties
• CPC Class Codes: B01J 35/33 : Electric or magnetic properties
• CPC Class Codes: B01J 35/393 : Metal or metal oxide crystallite size
• CPC Class Codes: B01J 35/40 : characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/51 : Spheres
• CPC Class Codes: B01J 35/613 : 10-100 m2/g
• CPC Class Codes: B01J 37/0054 : Drying of aerosols
• CPC Class Codes: B01J 37/343 : of ultrasonic wave energy
• CPC Class Codes: B22F 1/052 : characterised by a mixture of particles of different sizes or by the particle size distribution
• CPC Class Codes: B22F 1/054 : Nanosized particles
• CPC Class Codes: B22F 1/065 : Spherical particles
• CPC Class Codes: B22F 1/18 : Non-metallic particles coated with metal
• CPC Class Codes: B22F 2998/00 : Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 9/026 : Spray drying of solutions or suspensions
• CPC Class Codes: B22F 9/24 : starting from liquid metal compounds, e.g. solutions
• CPC Class Codes: B82Y 30/00 : Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 13/18 : by thermal decomposition of compounds, e.g. of salts or hydroxides
• CPC Class Codes: C01B 17/20 : Methods for preparing sulfides or polysulfides, in general ammonium sulfides or polysulfides C01C; sulfides or polysulfides of metals, other than alkali metals, magnesium, calcium, strontium and barium, see the relevant groups of subclasses C01F or C01G, according to the metal
• CPC Class Codes: C01G 23/003 : Titanates C01G23/001 takes precedence
• CPC Class Codes: C01P 2004/32 : Spheres
• CPC Class Codes: C01P 2004/61 : Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/22 : Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
• CPC Class Codes: C22C 29/00 : Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides C22C26/00 takes precedence
• CPC Class Codes: C22C 32/0084 : carbon or graphite as the main non-metallic constituent
• CPC Class Codes: H01L 23/49883 : the conductive materials containing organic materials or pastes, e.g. for thick films for printed circuits H05K1/092
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01M 12/08 : composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
• CPC Class Codes: H01M 4/8605 : Porous electrodes
• CPC Class Codes: H01M 4/90 : Selection of catalytic material
• CPC Class Codes: H01M 4/9016 : Oxides, hydroxides or oxygenated metallic salts
• CPC Class Codes: H01M 4/9083 : on carbon or graphite
• CPC Class Codes: H01M 4/926 : on carbon or graphite
• CPC Class Codes: H01M 8/1004 : characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H05K 1/095 : for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49108 : Electric battery cell making
• CPC Class Codes: Y10T 29/49115 : including coating or impregnating
• CPC Class Codes: Y10T 29/5313 : Means to assemble electrical device
• CPC Class Codes: Y10T 29/53135 : Storage cell or battery
• CPC Class Codes: Y10T 29/532 : Conductor
• CPC Class Codes: Y10T 29/53204 : Electrode

Abstract

Electrocatalyst powders and methods for producing electrocatalyst powders, such as carbon composite electrocatalyst powders. The powders have a well-controlled microstructure and morphology. The method includes forming the particles from an aerosol of precursors by heating the aerosol to a relatively low temperature, such as not greater than about 400° C.

Claims

1. A powder batch comprising composite electrocatalyst particles, said electrocatalyst particles comprising a support phase and an active species phase dispersed on said support phase, wherein said support phase comprises primary support particles having an average size of from about 10 to about 100 nanometers, wherein the average cluster size of said active species phase is not greater than about 20 nanometers and wherein said electrocatalyst particles have a surface area of at least about 90 m²/g.

2. A powder batch as recited in claim 1, wherein said active species phase has an average cluster size of from about 0.5 nanometers to about 5 nanometers.

3. A powder batch as recited in claim 1, wherein at least about 50 percent of said active species phase has a cluster size of not greater than about 3 nanometers.

4. A powder batch as recited in claim 1, wherein said active species phase comprises a metal.

5. A powder batch as recited in claim 1, wherein said active species phase comprises a platinum group metal.

6. A powder batch as recited in claim 1, wherein said active species phase comprises a metal oxide.

7. A powder batch as recited in claim 1, wherein said active species phase comprises a transition metal oxide.

8. A powder batch as recited in claim 1, wherein said active species phase comprises manganese oxide.

9. A powder batch as recited in claim 1, wherein said electrocatalyst particles have a surface area of at least about 200 m²/g.

10. A powder batch as recited in claim 1, wherein said primary support particles comprise carbon.

11. A powder batch as recited in claim 1, wherein said primary support particles comprise graphitic carbon.

12. A powder batch as recited in claim 1, wherein said electrocatalyst particles have an average particle size of not greater than about 10 μ

m.

13. A powder batch as recited in claim 1, wherein said electrocatalyst particles have an average particle size of from about 1 μ

m to about 10 μ

m.

14. A powder batch as recited in claim 1, wherein said electrocatalyst particles are substantially spherical.

15. A powder batch as recited in claim 1, wherein said electrocatalyst particles comprise from about 20 to about 40 weight percent of said active species phase.

16. A powder batch as recited in claim 1, wherein said electrocatalyst particles have a porosity of at least about 40 percent.

18. A powder batch as recited in claim 17, wherein said metallic active species phase comprises a platinum group metal.

19. A powder batch as recited in claim 17, wherein said metallic active species phase comprises platinum metal.

20. A powder batch as recited in claim 17, wherein said active species phase comprises a metal alloy.

21. A powder batch as recited in claim 17, wherein said electrocatalyst powders have a surface area of at least about 200 m²/g.

22. A powder batch as recited in claim 17, wherein said electrocatalyst powders have a porosity of at least about 40 percent.

23. A powder batch as recited in claim 17, wherein at least about 50 weight percent of said active species phase has a cluster size of not greater than about 3 nanometers.

25. A powder batch as recited in claim 24, wherein said metal oxide active species phase comprises a transition metal oxide.

26. A powder batch as recited in claim 24, wherein said metal oxide active species phase comprises manganese oxide.

27. A powder batch as recited in claim 24, wherein said electrocatalyst particles have a surface area of at least about 200 m²/g.

28. A powder batch as recited in claim 24, wherein said electrocatalyst particles have a porosity of at least about 40 percent.

30. A method as recited in claim 29, wherein said carrier gas is air.

31. A method as recited in claim 29, wherein said carrier gas is nitrogen.

32. A method as recited in claim 29, wherein said heating step comprises passing said droplets through a heating zone having a reaction temperature of not greater than about 400°

C.

33. A method as recited in claim 29, wherein said heating step comprises passing said droplets through a heating zone having a reaction temperature of not greater than about 300°

C.

34. A method as recited in claim 29, wherein said active species phase is a metal and wherein said precursor liquid further comprises a reducing agent.

35. A method as recited in claim 29, wherein said active species phase is a metal oxide and wherein said precursor liquid further comprises an oxidizing agent.

36. A method as recited in claim 29, wherein said first precursor comprises particulate carbon.

37. A method as recited in claim 29, wherein said first precursor comprises particulate carbon having a surface area of at least about 200 m²/g.

38. A method as recited in claim 29, wherein said first precursor comprises particulate carbon having an average size of from about 20 to about 40 nanometers.

39. A method as recited in claim 29, wherein said step of generating an aerosol comprises ultrasonically atomizing said liquid.

40. A method as recited in claim 29, wherein said step of generating an aerosol comprises passing said precursor liquid through a two-fluid nozzle.

17. A powder batch of metal-carbon composite electrocatalyst particles, said electrocatalyst particles comprising a carbon support phase and a metal active species phase dispersed on said support phase, wherein said support phase comprises primary carbon particles having an average size of from about 20 to about 40 nanometers and wherein the average cluster size of said metallic active species phase is not greater than about 10 nanometers.

24. A powder batch of composite electrocatalyst particles, said electrocatalyst particles comprising a carbon support phase and a metal oxide active species phase dispersed on said support phase, wherein said support phase comprises primary support particles having an average size of from about 20 to about 40 nanometers and wherein the average cluster size of said metal oxide active species phase is not greater than about 10 nanometers.

29. A method for the production of composite electrocatalyst particles, comprising the steps of:

a) generating an aerosol of droplets from a precursor liquid wherein said precursor liquid comprises at least a first precursor to a support phase and at least a second precursor to an active species phase;

b) moving said droplets in a carrier gas; and

c) heating said droplets to remove liquid therefrom and react at least one of said first and second precursors to form composite electrocatalyst particles wherein said active species phase is dispersed on said support phase.

41. A method for the production of composite electrocatalyst particles, comprising the steps of:

a) forming a liquid precursor comprising a particulate carbon precursor and at least a first precursor to an active species phase;

b) generating an aerosol of droplets from said liquid precursor; and

c) heating said aerosol of droplets in a spray dryer at a conversion temperature of not greater than about 400°

C. to form electrocatalyst particles wherein said first precursor is converted to an active species phase dispersed on said support phase.

42. A method as recited in claim 41, wherein said liquid precursor comprises a reducing agent.

43. A method as recited in claim 41, wherein said liquid precursor comprises an oxidizing agent.

44. A method as recited in claim 41, wherein said conversion temperature is not greater than about 300°

C.

45. A method as recited in claim 41, wherein said particulate carbon precursor has a surface area of at least about 600 m²/g.

46. A method as recited in claim 41, wherein said step of generating an aerosol comprises passing said liquid precursor through a two-fluid nozzle.