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

Patent metadata

Field	Value
Publication number	US-2017355607-A1
Application number	US-201515532877-A
Country	US
Kind code	A1
Filing date	Dec 4, 2015
Priority date	Dec 5, 2014
Publication date	Dec 14, 2017
Grant date	—

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

1 : 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)

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.

2 : The composite according to claim 1 , wherein the support is a basic, neutral, or weakly acidic metal oxide.

3 : The composite according to claim 1 , wherein the support is at least one metal oxide selected from the group consisting of ZrO 2 , TiO 2 , CeO 2 , Al 2 O 3 , Nb 2 O 5 , Ta 2 O 5 , and MgO.

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

5 : The composite according to claim 1 , wherein the metal atom M is Ca.

6 : The composite according to claim 1 , wherein the transition metal is Ru.

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

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

9 : A method of producing the composite according to claim 1 , the method comprising:
mixing a metal atom source comprising the metal atom M, the support, and liquid ammonia; and reacting the metal atom source with the liquid ammonia to form a metal amide-supporting support comprising the metal amide compound on the support.

10 : The method of producing a composite according to claim 9 , further comprising:
supporting as a transition metal raw material on the metal amide-supporting support; and depositing the transition metal by thermally decomposing the transition metal raw material.

11 : 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 8 to synthesize ammonia.

12 : The method for synthesizing ammonia according to claim 11 , 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.

13 : The method for synthesizing ammonia according to claim 11 , wherein the pressure when contacting the ammonia synthesis catalyst is 10 kPa or more and 20 MPa or less.

Assignees

• Japan Science & Tech Agency
• Tokyo Inst Tech

Inventors

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

Classifications

• C01B21/0926

  of alkali metals · CPC title

• C01B21/0923

  Metal imides or amides · CPC title

• B01J37/086

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

• B01J23/58

  with alkali- or alkaline earth metals · CPC title

• B01J27/24

  Nitrogen compounds · CPC title