Support metal catalyst and method for synthesizing ammonia using same catalyst
|発明の名称 （英語）||Support metal catalyst and method for synthesizing ammonia using same catalyst|
|発明の概要（英語）||A catalyst for continuous synthesis of ammonia using gas containing hydrogen and nitrogen as raw materials is characterized in that a vector supporting a transition metal exhibiting catalytic activity is a two-dimensional electride or a precursor thereof. The two-dimensional electride or the precursor thereof is: MxNyHz (M is one or more types of group 2 metals selected from the group consisting of Mg, Ca, Sr, and Ba; x, y, and z are defined as 1 <= x <= 11, 1 <= y <= 8, and 0 <= z <= 4, respectively; x is an integer; and y and z are not limited to being integers); a metal nitride represented by M3N2 (M being as defined above); or a metal carbide selected from the group consisting of Y2C, Sc2C, Gd2C, Tb2C, Dy2C, Ho2C, and Er2C. Using such catalysts, the nitrogen and hydrogen as raw materials are continuously reacted on the catalyst in an ammonia synthesis reaction device under the following conditions: a reaction temperature of preferably 100 to 600 DEG C and a reaction pressure of 10 kPa or greater and less than 20 MPa.|
To M3 N2 (Mas Ca, Sr or Ba) an alkaline earth metal nitride is applied to a semiconductor device represented by an aluminum nitride, ceramic particles of metal for sliding member, battery electrode material, conductive particles and the like (Patent Document 1). Patent Document 1 discloses the 2nd group metal made of a heat decomposing amino compound M3 N2 (Mas Be, Mg, Ca, Sr or Ba) or M2 N(Mas Be, Mg, Ca, Sr or Ba) or the like method. Patent Document 2 discloses the ammonia from the 2nd-group metal reaction, to give the layer to liquefy 2nd metal amino compound, and the 2nd-group metal heat decomposition of high-purity amino compound M3 N2 (Mas Be, Mg, Ca, Sr or Ba) of the method.
To date, α-Ca3 N2, β-Ca3 N2, γ-Ca3 N2, Ca11 N8, Ca2 Nor the like as are well-known calcium nitride. In addition, calcium nitride hydride Ca2 NH,CaNH,Ca(NH2)2 or the like (hereinafter referred to as "Ca-N-H-based compound") have also been known to the art.
Ca3 N2 that the Ca dissolved in liquid ammonia, and is prepared by heat decomposition under a nitrogen atmosphere. As shown in the following reaction formula, Ca3 N2 and the moisture in the air react to form calcium hydroxide and ammonia. The reaction may be carried out in water.
Ca3 N2 +6H2 O→3Ca (OH)2 +2NH3
In addition, it is known that Ca2 Nis easily oxidized, is extremely unstable substance, has been reported Ca2 Nstably present in a range of not more than 1000 °C to 250 °C in nitrogen gas or argon gas to 800 °C (Non-Patent Document 1).
On the other hand, the present invention have been found in the human 2013 Ca2 Nis a two-dimensional electron-accepting compound (Non-Patent Document 2). Ca2 N:e- is an electron as an anion incorporated into the [Ca2 N]+ serving as a layer to form a layered inorganic compound, may be heat under vacuum conditions through Ca3 N2 is produced and metal Ca. It has been reported that Ca2 N:e- conduction electron concentration of 1.39x1022 /cm3, 2.6eV having a work function. Then, reported in Non-Patent Document 3 in which the two-dimensional electron-donating compound.
The present invention having a layered crystal structure and is made for al.also to Ionization [AE2 N]+ e- nitride represented by (AE is selected from Ca, Sr, Ba of at least one element) consisting of a nitride-donating compound related to the invention is directed to patent application (Patent Document 3).
On the other hand, to a gas containing hydrogen and nitrogen as a raw material, an iron oxide as a catalyst, such as aluminum oxide, potassium oxide as a promoter of the Haber-Bosch ammonia synthesis method is widely used. This method is no appreciable change 100 years. By Haber-Bosch process for ammonia synthesis is at 300 °C-500 °C, 20-40 mpa of the high temperature and pressure, allowing nitrogen gas and hydrogen gas is carried out by reacting on the catalyst.
VIII metal of Group VIB metals and a ternary nitride (Patent Document 4), cobalt-molybdenum complex nitride (Patent Document 5) or the like as are well-known ammonia synthesis catalyst as well. The present invention in a mayenite type compound is ammonia synthesis catalyst carrier been developed a load of the metal catalyst (Patent Document 6-7, Non-Patent Document 4-5).
Prior Art Document
Patent Document 1: Japanese Laid-Open No.4585043 (US2012225005A1)
Patent Document 2: Japanese Laid-Open Publication No.2012-66991 (Japanese Patent 5627105)
Patent Document 3: Japanese Laid-Open Publication No.2014-24712
Patent Document 4: Japanese Laid-Open Publication No.2000-264625 (US6235676B1)
Patent Document 5: Japanese Laid-Open Publication No.2001-096163 (Patent 4038311)
Patent Document 6: WO2012/077658(US2013183224A1)
Patent Document 7:WO2014/034473
Non-Patent Document 1: P.Hchn,S.Hoffmann,J.Hunger,S.Leoni,F.Nitsche,W.Schnelle,R.Kniep, "Chem.Eur.J.", 15,3419 (2009)
Non-Patent Document 2: K.Lee,S.W.Kim,Y.Toda,S.Matsuishi and H.Hosono, "Nature", 494,336-341 (2013)
Non-Patent Document 3: A.Walsh and D.O.Scanlon, "Journal of materials Chemistry"C,1,3525-3528 (2013)
Non-Patent Document 4: M.Kitano,Y.Inoue,Y.Yamazaki,F.Hayashi,S.Kanbara,S.Matsuishi,T.Yokoyama,S.W.Kim,M.Hara and H.Hosono, "Nature Chemistry"vol.4,934-940 (2012)
Non-Patent Document 5: Y.Inoue,M.Kitano,S.W.Kim,T.Yokoyama,M.Hara and H.Hosono, "ACS Catal."4 (2), 674-680 (2014)
1. An ammonia synthesis is being supported metal catalyst, hydrogen and nitrogen gas as a raw material so as to comprise a continuous ammonia synthesis catalyst used, characterized in,
The load of a catalytically active transition metal of vector is a two-dimensional electron-donating compound or a precursor thereof.
2. Supported metal catalysts for ammonia synthesis according to claim 1, characterized in, two-dimensional electron-donating compound or its precursor is a metal nitride or a hydride to MxNyHz representation,
Wherein, M is a group consisting of Mg, Ca, Sr and the 2nd group metals Ba of the group consisting of one or two or more, x, y, z ranges from 1 ≤ x ≤ 11,1 ≤ y ≤ 8,0 ≤ z ≤ 4, x is an integer, y, z are not limited to integers.
3. Supported metal catalyst for ammonia synthesis according to claim 1, characterized in, two-dimensional electron-donating compound or its precursor is to M3 N2 represents a metal nitride,
Wherein, M is a group consisting of Mg, Ca, Sr and the 2nd group metals Ba of the group consisting of one or two or more.
4. Supported metal catalysts for ammonia synthesis according to claim 1, characterized in, two-dimensional electron-donating compound or its precursors are Ca2 Nrepresents calcium nitride.
5. Supported metal catalyst for ammonia synthesis according to claim 1, characterized in, two-dimensional electron-donating compound or its precursor is selected from Y2 C,Sc2 C,Gd2 C,Tb2 C,Dy2 C,Ho2 Cand the Er2 Cthe group consisting of a metal carbide or a hydrogenized product thereof are.
6. Ammonia synthesis for supporting the metal catalyst according to claim 1, characterized in, transition metal is loaded with respect to the carrier is a 0.01-30 wt %.
7. A supported metal catalyst for ammonia synthesis according to claim 1, characterized in, transition metal is selected from a Ru, Fe the group consisting of Co and the at least one.
8. Claim 1-7 catalyst prepared according to any one of the method, characterized in, with a dipping method, a physical mixing method, the thermal decomposition method, liquid phase method or a vapor deposition method comprising carbonizing the transition metal compound powder supported on a carrier.
9. An ammonia synthesis method, characterized in, employed in any one claim 1-7 catalyst, the ammonia synthesis reaction apparatus, at a reaction temperature of 100 °C or more and 600 °C or less, a reaction pressure of 10kPa or more and less than 20 mpa conditions, the raw material nitrogen and hydrogen reaction continuously on the catalyst.
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