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