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Intermetallic compound, hydrogen storage/release material, catalyst and method for producing ammonia

Foreign code F210010315
File No. J1014-29WO
Posted date Jan 29, 2021
Country United States of America
Application number 201816630269
Gazette No. 20200164348
Date of filing Jul 12, 2018
Gazette Date May 28, 2020
International application number JP2018026287
International publication number WO2019013272
Date of international filing Jul 12, 2018
Date of international publication Jan 17, 2019
Priority data
  • P2017-135875 (Jul 12, 2017) JP
  • 2018JP26287 (Jul 12, 2018) WO
Title Intermetallic compound, hydrogen storage/release material, catalyst and method for producing ammonia
Abstract Provided are an intermetallic compound having high stability and high activity, and a catalyst using the same. A hydrogen storage/release material containing an intermetallic compound represented by formula (1): RTX . . . (1) wherein R represents a lanthanoid element, T represents a transition metal in period 4 or period 5 in the periodic table, and X represents Si, Al or Ge.
Outline of related art and contending technology BACKGROUND ART
In the Haber-Bosch process, a typical process for synthesizing ammonia, ammonia is produced by using doubly promoted iron containing Fe3O4 and a few % by mass of Al2O3 and K2O as a catalyst and contacting the catalyst with a mixed gas of nitrogen and hydrogen under a high temperature, high pressure condition.
Meanwhile, studies have been conducted on a process for synthesizing ammonia at a temperature lower than the reaction temperature applied in the Haber-Bosch process, and a study proposes a process using ruthenium (Ru) supported on various carriers as a catalytically active component as a catalyst for ammonia synthesis (for example, Patent Literature 1). It has been known that since catalysts using a transition metal such as Ru have a very high activity, ammonia can be synthesized with them under reaction conditions milder than those in the Haber-Bosch process. For example, although the Haber-Bosch process requires a reaction temperature of 400° C. or more and a reaction pressure of 10 MPa or more, in the case of a catalyst using Ru, reaction progresses at a reaction temperature of about 200° C. and a reaction pressure of 1.1 MPa or less, or even about atmospheric pressure.
Furthermore, intermetallic compounds have been considered as another catalyst for ammonia synthesis. An intermetallic compound of a transition metal such as Ru having high catalytic activity with other metal elements is a promising, inexpensive catalyst.
Examples of intermetallic compounds active in the synthesis of ammonia include intermetallic compounds of an alkali metal or alkaline earth metal and a transition metal, such as CaNi5, Mg2Ni and Mg2Cu (Patent Literature 2) and intermetallic compounds such as CeFe2, CeCo2 and CeRu2, which are known as a hydrogen storage alloy (Non Patent Literatures 1, 2). More specifically, Non Patent Literature 1 reports the results of synthesis of ammonia using a powder of an intermetallic compound such as CeFe2, CeRu2 or CeCo2, which has been prepared by a melting method while substituting the catalyst with a metal itself.
Furthermore, a method using the hydride AB5H˜6 prepared by reducing an intermetallic compound represented as an AB5-type intermetallic compound as a catalyst has been proposed. More specifically, the study reports that ammonia can be synthesized at room temperature by using, as a catalyst, a hydride prepared by reducing the above AB5-type intermetallic compound wherein A is a misch metal containing La as a main component and B is Ni and which has a BET specific surface area of 0.02 m2/g (Non Patent Literature 3).
It has also been known that intermetallic compounds are embrittled and crushed due to storage of hydrogen and a fine intermetallic compound is obtained due to release of hydrogen.
Scope of claims [claim1]
1. An activator for hydrogenation reaction, comprising an intermetallic compound represented by formula (1):
RTX  (1)
wherein
R represents a lanthanoid element,
T represents a transition metal in period 4 or period 5 in the periodic table, and
X represents Si, Al or Ge.

[claim2]
2. A method for using an intermetallic compound represented by formula (1), comprising contacting the intermetallic compound with hydrogen to activate a bond in a hydrogen molecule:
RTX  (1)
wherein
R represents a lanthanoid element,
T represents a transition metal in period 4 or period 5 in the periodic table, and
X represents Si, Al or Ge.

[claim3]
3. A catalyst comprising an intermetallic compound represented by formula (1):
RTX  (1)
wherein
R represents a lanthanoid element,
T represents a transition metal in period 4 or period 5 in the periodic table, and
X represents Si, Al or Ge.

[claim4]
4. The catalyst according to claim 3, wherein the catalyst is a catalyst for ammonia synthesis.

[claim5]
5. A transition metal-supported intermetallic compound comprising a transition metal M supported on an intermetallic compound represented by formula (1):
RTX  (1)
wherein
R represents a lanthanoid element,
T represents a transition metal in period 4 or period 5 in the periodic table, and
X represents Si, Al or Ge.

[claim6]
6. An activator for hydrogenation reaction, comprising the transition metal-supported intermetallic compound according to claim 5.

[claim7]
7. A method for using the transition metal-supported intermetallic compound according to claim 5, comprising contacting the intermetallic compound with hydrogen to activate a bond in a hydrogen molecule.

[claim8]
8. A catalyst comprising the transition metal-supported intermetallic compound according to claim 5.

[claim9]
9. The catalyst according to claim 8, wherein the catalyst is a catalyst for ammonia synthesis.

[claim10]
10. An intermetallic compound-hydrogen complex represented by formula (2), wherein the intermetallic compound is capable of storing and releasing hydrogen reversibly and the complex is capable of releasing hydrogen at 400° C. or less:
RTX·aH  (2)
wherein
R represents a lanthanoid element,
T represents a transition metal in period 4 or period 5 in the periodic table,
X represents Si, Al or Ge and
a represents a number of 0.5 or more and 1.5 or less.

[claim11]
11. A catalyst comprising the complex according to claim 10.

[claim12]
12. The catalyst according to claim 11, wherein the catalyst is a catalyst for ammonia synthesis.

[claim13]
13. A transition metal-supported complex comprising a transition metal M supported on the complex according to claim 10.

[claim14]
14. A catalyst comprising the transition metal-supported complex according to claim 13.

[claim15]
15. The catalyst according to claim 14, wherein the catalyst is a catalyst for ammonia synthesis.

[claim16]
16. A method for producing ammonia, comprising contacting nitrogen and hydrogen with a catalyst, wherein the catalyst is a catalyst according to claim 4.

[claim17]
17. The activator for hydrogenation reaction according to claim 1, wherein X is Si or Ge.

[claim18]
18. The activator for hydrogenation reaction according to claim 1, wherein T is Sc, Fe, Ru, Co, Rh or Ti.

[claim19]
19. The activator for hydrogenation reaction according to claim 1, wherein R is La, Gd or Ce.
  • Inventor, and Inventor/Applicant
  • HOSONO HIDEO
  • GONG YUTONG
  • WU JLAZHEN
  • KITANO MASAAKI
  • YOKOYAMA TOSHIHARU
  • LU YANGFAN
  • YE TIANNAN
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • TOKYO INSTITUTE OF TECHNOLOGY
IPC(International Patent Classification)
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