Accelerated hydrogen generation through reactive mixing of two or more fluids

• US 6,818,334 B2
• Filed: 06/06/2002
• Issued: 11/16/2004
• Est. Priority Date: 06/06/2002
• Status: Expired due to Term

• Current Assignee: Intelligent Energy Limited (Lb-shell Plc)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Tsang, Joseph W.
• Primary Examiner(s): Ruthkosky, Mark
• Application Number:
  US10/165,370
• Publication Number:
  US 20030228505A1
• Time in Patent Office: 894 Days
• Field of Search: 429/17
• US Class Current: 429/421
• CPC Class Codes: C01B 2203/066 with fuel cells
• CPC Class Codes: C01B 3/065 from a hydride
• CPC Class Codes: F17C 11/005 for hydrogen
• CPC Class Codes: H01M 8/065 by dissolution of metals or alloys; by dehydriding metallic substances
• CPC Class Codes: Y02E 60/32 Hydrogen storage
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The rate of hydrogen generation in proton-exchange-membrane (PEM) fuel cells is greatly accelerated by mixing a first aqueous alkali borohydride solution with a second aqueous solution in the presence of one or more transition metal catalysts:

wherein the first solution comprises (a) 5 to 50 wt % MBH₄, where M is an alkali metal, (b) 5 to 40 wt % alkali hydroxide or alkaline metal hydroxide, and (c) the balance water, and wherein the second solution comprises (a) 51 to 100% water, and (b) the balance, if any, comprising at least one water-soluble additive.

Claims

1. A proton-exchange-membrane fuel cell comprising a cathode, an anode, and a proton-exchange-membrane disposed therebetween and a reaction chamber for generating hydrogen gas employing a catalyst, said hydrogen gas being delivered to said anode, wherein a mechanism is provided for introducing a first solution and a second solution into said reaction chamber to form a mixture, said first solution comprising (a) 5 to 50 wt % MBH₄, where M is an alkali metal, (b) 5 to 40 wt % alkali hydroxide or alkaline metal hydroxide, and (c) the balance water, and said second solution comprising (a) 51 to 100% water, and (b) the balance, if any, comprising at least one water-soluble additive.

2. The fuel cell of claim 1 wherein M is selected from the group consisting of sodium, potassium, and lithium.

3. The fuel cell of claim 1 wherein said alkali hydroxide is selected from the group consisting of NaOH, KOH, and LiOH.

4. The fuel cell of claim 1 wherein said alkaline metal hydroxide is selected from the group consisting of Ca(OH)₂ and Mg(OH)₂.

5. The fuel cell of claim 1 wherein said second solution has a pH that is within a range of about −

2 to 7.

6. The fuel cell of claim 1 wherein said catalyst comprises at least one transition metal selected from the group consisting of Groups IB to VIII of the Periodic Table.

7. The fuel cell of claim 6 wherein said transition metal is selected from the group consisting of ruthenium, osmium, and platinum.

8. The fuel cell of claim 1 wherein in said reaction chamber, said mixture has a molar ratio of within a ratio of 5:

1 to 50;

1 of water;

MBH₄.

9. The fuel cell of claim 1 wherein said at least one water-soluble additive is selected from the group consisting of:

(1) alcohols of C₁-C₁₀, (2) ethylene glycol and higher homologs, (3) diols and triols of C₃ to C₂₀, (4) non-ionic surfactants, (5) mineral acids, and (6) alkyl and aryl carboxylic acids, alkyl and aryl sulfonic acids, alkyl and aryl phosphoric acids, and alpha-hydroxy acids.

10. The fuel cell of claim 9 wherein said non-ionic surfactants are selected from the group consisting of secondary alcohol ethoxylates, acetylenic polyethylene oxides, polyethylene oxide block copolymers, polyethylene oxide ethers.

11. The fuel cell of claim 1 wherein said reaction chamber is provided with a heating mechanism to heat said reaction chamber to a temperature less than the boiling points of said first solution and said second solution.

12. A proton-exchange-membrane fuel cell comprising a cathode, an anode, and a proton-exchange-membrane disposed therebetween and a reaction chamber for generating hydrogen gas employing a catalyst, said hydrogen gas being delivered to said anode, wherein a mechanism is provided for introducing a first solution and a second solution into said reaction chamber to form a mixture, said first solution comprising (a) 15 to 50 wt % NaBH₄, (b) 5 to 40 wt % sodium hydroxide, and (c) the balance water, and said second solution comprising (a) 51 to 100% water, and (b) the balance, if any, comprising at least one water-soluble additive.

13. The fuel cell of claim 12 wherein said second solution has a pH that is within a range of about −

2 to 7.

14. The fuel cell of claim 12 wherein said catalyst comprises at least one transition metal selected from the group consisting of Groups IB to VIII of the Periodic Table.

15. The fuel cell of claim 14 wherein said transition metal is selected from the group consisting of ruthenium, osmium, and platinum.

16. The fuel cell of claim 12 wherein in said reaction chamber, said mixture has a molar ratio of within a ratio of 5:

1 to 50;

1 of water;

NaBH₄.

17. The fuel cell of claim 12 wherein said at least one water-soluble additive is selected from the group consisting of:

(1) alcohols of C₁-C₁₀, (2) ethylene glycol and higher homologs, (3) diols and triols of C₃ to C₂₀, (4) non-ionic surfactants, (5) mineral acids, and (6) alkyl and aryl carboxylic acids, alkyl and aryl sulfonic acids, alkyl and aryl phosphoric acids, and alpha-hydroxy acids.

18. The fuel cell of claim 17 wherein said non-ionic surfactants are selected from the group consisting of secondary alcohol ethoxylates, acetylenic polyethylene oxides, polyethylene oxide block copolymers, polyethylene oxide ethers.

19. The fuel cell of claim 12 wherein said reaction chamber is provided with a heating mechanism to a temperature less than the boiling points of said first solution and said second solution.

20. A method of operating a proton-exchange-member fuel cell comprising a cathode, an anode, and a proton-exchange-membrane disposed therebetween, wherein said fuel cell is supplied with hydrogen gas from a reaction chamber that generates said hydrogen gas employing a catalyst, said hydrogen gas being delivered to said anode, said method comprising:

introducing a first solution and a second solution into said reaction chamber to form a mixture, said first solution comprising (a) 5 to 50 wt % MBH₄, where M is an alkali metal, (b) 5 to 40 wt % alkali hydroxide or alkaline metal hydroxide, and (c) the balance water, and said second solution comprising (a) 51 to 100% water, and (b) the balance, if any, comprising at least one water-soluble additive.

21. The method of claim 20 wherein M is selected from the group consisting of sodium, potassium, and lithium.

22. The method of claim 20 wherein said alkali hydroxide is selected from the group consisting of NaOH, KOH, and LiOH.

23. The method of claim 20 wherein said alkaline metal hydroxide is selected from the group consisting of Ca(OH)₂ and Mg(OH)₂.

24. The method of claim 20 wherein said second solution has a pH that is within a range of about −

2 to 7.

25. The method of claim 20 wherein said catalyst comprises at least one transition metal selected from the group consisting of Groups 1B to VII of the Periodic Table.

26. The method of claim 25 wherein said transition metal is selected from the group consisting of ruthenium, osmium, and platinum.

27. The method of claim 20 wherein in said reaction chamber, said mixture has a molar ratio of within a ratio of 5:

1 to 50;

1 of water;

MBH₄.

28. The method of claim 20 wherein said at least one water-soluble additive is selected from the group consisting of:

(1) alcohols of C₁-C₁₀, (2) ethylene glycol and higher homologs, (3) diols and triols of C₃ to C₂₀, (4) non-ionic surfactants, (5) mineral acids, and (6) alkyl and aryl carboxylic acids, alkyl and aryl sulfonic acids, alkyl and aryl phosphoric acids, and alpha-hydroxy acids.

29. The method of claim 28 wherein said non-ionic surfactants are selected from the group consisting of secondary alcohol ethoxylates, acetylenic polyethylene oxides, polyethylene oxide block copolymers, polyethylene oxide ethers.

30. The method of claim 20 wherein said first solution and said second solution are metered separately from separate reservoirs and mixed within said reaction chamber.

31. The method of claim 20 wherein said reaction chamber is heated to increase reaction rate of said first solution and said second solution in the presence of said catalyst.

32. The method of claim 31 wherein said reaction chamber is heated to a temperature less than the boiling points of said first solution and said second solution.