Composite, method for producing composite, ammonia synthesis catalyst, and ammonia synthesis method

Patent metadata

Field	Value
Publication number	US-10322940-B2
Application number	US-201515532877-A
Country	US
Kind code	B2
Filing date	Dec 4, 2015
Priority date	Dec 5, 2014
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

An ammonia synthesis catalyst having high activity is obtained by having a two-dimensional electride compound having a lamellar crystal structure such as Ca 2 N support a transition metal. However, since the two-dimensional electride compound is unstable, the stability of the catalyst is low. In addition, in cases where a two-dimensional electride compound is used as a catalyst support, it is difficult to shape the catalyst depending on reactions since the two-dimensional electride compound has poor processability. A composite which includes a transition metal, a support and a metal amide compound, wherein the support is a metal oxide or a carbonaceous support; and the metal amide compound is a metal amide compound represented by general formula (1).

M(NH 2 ) x   (1)

(In general formula (1), M represents at least one metal atom selected from the group consisting of Li, Na, K, Be, Mg, Ca, Sr, Ba and Eu; and x represents the valence of M.).

First claim

What is claimed is:

1. A composite, comprising Ru, a support, and a metal amide compound, wherein:
the support is at least one metal oxide selected from the group consisting of ZrO 2 , TiO 2 , CeO 2 , and MgO; and
the metal amide compound is Ca(NH 2 ) 2 .

2. The composite according to claim 1 , wherein the composite has a BET specific surface area of 10 m 2 /g or more.

3. A supported metal catalyst, comprising the composite according to claim 1 .

4. An ammonia synthesis catalyst, comprising the composite according to claim 1 .

5. A method of producing a composite comprising a transition metal, a support, and a metal amide compound, wherein:
the support is a metal oxide or a carbonaceous support;
the metal amide compound is a compound represented by formula (1):
M(NH 2 ) x   (1);

wherein
M represents at least one metal atom selected from the group consisting of Li, Na, K, Be, Mg, Ca, Sr, Ba and Eu; and
x represents the valence of M,
the method of producing the composite comprising:
mixing a metal atom source comprising the metal atom M, the support, and liquid ammonia;
reacting the metal atom source with the liquid ammonia to form a metal amide-supporting support comprising the metal amide compound on the support; and
supporting the transition metal on the metal amide-supporting support.

6. The method of producing a composite according to claim 5 , wherein the supporting of the transition metal on the metal amide-supporting support comprises:
supporting a transition metal raw material on the metal amide-supporting support; and
depositing the transition metal by thermally decomposing the transition metal raw material.

7. A method of synthesizing ammonia, the method comprising contacting a gas comprising nitrogen and a gas comprising hydrogen with the ammonia synthesis catalyst according to claim 4 to synthesize ammonia.

8. The method for synthesizing ammonia according to claim 7 , wherein a temperature at which the ammonia synthesis catalyst is brought into contact with the ammonia synthesis catalyst is 100° C. or more and 600° C. or less.

9. The method for synthesizing ammonia according to claim 7 , wherein the pressure when contacting the ammonia synthesis catalyst is from 10 kPa to 20 MPa.

10. A method of producing the composite according to claim 7 , comprising:
mixing a metal atom source comprising Ca, the support, and liquid ammonia;
reacting the metal atom source with the liquid ammonia to form metal amide-supporting support comprising the metal amide compound on the support; and
supporting Ru on the metal amide-supporting support.

11. The composite according to claim 1 , wherein the at least one metal oxide selected from the group consisting of ZrO 2 , TiO 2 , and CeO 2 .

Assignees

• Japan Science & Tech Agency
• Tokyo Inst Tech

Inventors

• Hosono Hideo
• Hara Michikazu
• Kitano Masaaki
• Yokoyama Toshiharu
• Inoue Yasunori

Classifications

• C01P2004/04

  obtained by TEM, STEM, STM or AFM · CPC title

• C01B21/0926

  of alkali metals · CPC title

• C01B21/0923

  Metal imides or amides · CPC title

• C01B3/047

  Decomposition of ammonia · CPC title

• B01J37/086

  Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid · CPC title