CATALYST FOR DECOMPOSITION OF FORMIC ACID, METHOD FOR DECOMPOSING FORMIC ACID, PROCESS FOR PRODUCING HYDROGEN, APPARATUS FOR PRODUCING AND DECOMPOSING FORMIC ACID, AND METHOD FOR STORING AND GENERATING HYDROGEN

• US 20100034733A1
• Filed: 05/17/2007
• Published: 02/11/2010
• Est. Priority Date: 11/17/2006
• Status: Active Grant

• Current Assignee: Osaka University
• Original Assignee: Osaka University
• Inventors: Ogo, Seiji, Suenobu, Tomoyoshi, Fukuzumi, Shunichi
• Granted Patent: US 7,939,461 B2
• Time in Patent Office: Days
• US Class Current: 423/658.200
• CPC Class Codes: B01J 2531/0219 Bimetallic complexes, i.e. comprising one or more units of two metals, with metal-metal bonds but no all-metal (M)n rings, e.g. Cr2(OAc)4
• CPC Class Codes: B01J 2531/821 Ruthenium
• CPC Class Codes: B01J 2531/827 Iridium
• CPC Class Codes: B01J 31/1815 with more than one complexing nitrogen atom, e.g. bipyridyl, 2-aminopyridine
• CPC Class Codes: B01J 31/2295 Cyclic compounds, e.g. cyclopentadienyls
• CPC Class Codes: C01B 2203/0277 containing a catalytic decomposition step
• CPC Class Codes: C01B 2203/1041 Composition of the catalyst
• CPC Class Codes: C01B 2203/1047 Group VIII metal catalysts
• CPC Class Codes: C01B 2203/1211 Organic compounds or organic mixtures used in the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 3/22 by decomposition of gaseous or liquid organic compounds C01B3/0005 takes precedence ; coking liquid carbonaceous materials C10B55/00
• CPC Class Codes: C01B 3/32 by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air

Abstract

The present invention provides a catalyst for the decomposition of formic acid including a dinuclear metal complex represented by a formula (1) below, a tautomer or stereoisomer thereof, or any of their salts,

• • where M¹ and M² are transition metals and may be the same or different; Ar is a ligand having aromaticity and may be unsubstituted or substituted by one or more substituents; R¹ to R²⁷ are each independently a hydrogen atom, an alkyl group, or the like, or R¹⁵ and R¹⁶ may together form a —CH═CH—, where Hs in the —CH═CH— may be each independently replaced by an alkyl group or the like, and R²³ and R²⁴ may together form a —CH═CH—, where Hs in the —CH═CH— may be each independently replaced by an alkyl group or the like; L is an arbitrary ligand or is absent; and m is a positive integer, 0, or a negative integer.

Claims

1. A catalyst for decomposition of formic acid comprising a dinuclear metal complex represented by a formula (1) below, a tautomer or stereoisomer thereof, or any of their salts,

2. The catalyst for the decomposition of formic acid according to claim 1, wherein in the formula (1), the one or more substituents on Ar are each independently an alkyl group, a phenyl group, or a cyclopentadienyl group.

3. The catalyst for the decomposition of formic acid according to claim 1, wherein in the formula (1), L is a water molecule, a hydrogen atom, an alkoxide ion, a hydroxide ion, a halide ion, a carbonate ion, a trifluoromethanesulfonate ion, a sulfate ion, a nitrate ion, a formate ion, or an acetate ion or is absent.

4. The catalyst for the decomposition of formic acid according to claim 1, wherein all of R¹ to R⁵ are methyl groups.

5. The catalyst for the decomposition of formic acid according to claim 1, wherein all of R¹² to R²⁷ are hydrogen atoms.

6. The catalyst for the decomposition of formic acid according to claim 1, wherein M¹ is ruthenium, osmium, iron, manganese, chromium, cobalt, iridium, or rhodium.

7. The catalyst for the decomposition of formic acid according to claim 1, wherein M² is iridium, ruthenium, rhodium, cobalt, osmium, nickel, or platinum.

8. The catalyst for the decomposition of formic acid according to claim 1, wherein M¹ is ruthenium and M² is iridium.

9. The catalyst for the decomposition of formic acid according to claim 1, wherein m is 2, 3, or 4.

10. The catalyst for the decomposition of formic acid according to claim 1, wherein the dinuclear metal complex of the formula (1) is a dinuclear metal complex having a structure represented by a formula (6) below,

11. The catalyst for the decomposition of formic acid according to claim 10, wherein all of R⁶ to R²⁷ are hydrogen atoms.

12. The catalyst for the decomposition of formic acid according to claim 11, which is represented by a formula (7) below,

13. The catalyst for the decomposition of formic acid according to claim 12, which is represented by any one of formulae (8) to (11) below.

14. A method for decomposing formic acid comprising at least one step selected from the group consisting of the steps of allowing a solution containing the catalyst for the decomposition of formic acid according to claim 1 and formic acid to stand as it is;

heating the solution; and

irradiating the solution with light.

15. The method according to claim 14, wherein the solution is an aqueous solution.

16. A process for producing hydrogen (H₂) comprising the step of generating hydrogen (H₂) by decomposing formic acid by the method according to claim 14.

17. An apparatus for producing and decomposing formic acid, comprising a formic acid decomposing portion for generating hydrogen (H₂) and carbon dioxide (CO₂) by decomposing formic acid and a formic acid producing portion for producing formic acid from hydrogen (H₂) and carbon dioxide (CO₂),

wherein the formic acid decomposing portion contains the catalyst for the decomposition of formic acid according to claim 1;

and

the formic acid producing portion contains a catalyst for production of formic acid for producing formic acid by reacting hydrogen (H₂) with carbon dioxide (CO₂).

18. A method for storing and generating hydrogen comprising the following steps:

a hydrogen storing step of producing formic acid by reacting hydrogen (H₂) with carbon dioxide (CO₂) using a catalyst for the production of formic acid, and storing the hydrogen in a form of formic acid; and

a hydrogen generating step of generating hydrogen (H₂) and carbon dioxide (CO₂) by decomposing the formic acid using the catalyst for the decomposition of formic acid according to claim 1.