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COMPOSITE OXIDE, METAL-SUPPORTED MATERIAL, AND AMMONIA SYNTHESIS CATALYST

Foreign code F200010030
File No. AF40-05WO
Posted date Jan 31, 2020
Country WIPO
International application number 2019JP018225
International publication number WO 2019216304
Date of international filing May 7, 2019
Date of international publication Nov 14, 2019
Priority data
  • P2018-089516 (May 7, 2018) JP
  • 2018JP34515 (Sep 18, 2018) WO
  • P2019-059200 (Mar 26, 2019) JP
Title COMPOSITE OXIDE, METAL-SUPPORTED MATERIAL, AND AMMONIA SYNTHESIS CATALYST
Abstract The present invention is a composite oxide including a metal element represented by the composition of general formula (6), wherein the composite oxide comprises an oxide of A and an oxide of X in a mixed state. General formula (6): AnXy (in general formula (6), A represents an element selected from the group consisting of Sc, Y, and lanthanoids(III); X represents an element selected from the group consisting of Ca, Sr, and Ba; n is 0 < n < 1; y is 0 < y < 1; and n + y = 1). The present invention is also a metal-supported material characterized in that cobalt particles are supported on the aforementioned composite oxide.
Outline of related art and contending technology BACKGROUND ART
Ammonia, in the chemical industry is an important raw material of the modern. 80% Or more of ammonia production, agricultural product for the production of chemical fertilizers are used. Further, ammonia, hydrogen energy garnered much attention as a carrier. Which is connected, (1) the content of hydrogen (17.6wt %), (2) high energy density (12.8GJ/m3), (3) when decomposed to produce hydrogen and carbon dioxide is generated from this. Renewable energy such as wind power or solar energy efficiently can be produced if the ammonia, the energy and food crisis associated with the global problem is mitigated.
Current, is used to produce ammonia Haber, the Bosch method, and a large consumption of energy, the amount thereof is about 1-2% of the world's energy consumption occupies. In this method, the energy consumption of about 60% is recovered and, as the enthalpy of the ammonia is ensured. However, the majority of the remainder of the energy, during the production of hydrogen from natural gas, ammonia synthesis, and are lost during the separation. Hard bar, Bosch ammonia synthesis method is a very high temperature and pressure (450°C>) and so on (20mpa>), the large amount of energy used in the method are required to be reduced. Global energy consumption is suppressed, the Haber, the Bosch method used in a mild condition than the iron-based catalysts (lower temperatures and pressures) can be synthesized under ammonia catalyst is required.
In recent years, the order of 1mpa (10 atm) under low pressure conditions has been known a method of producing ammonia. Ruthenium catalyst is used in the production of ammonia, is generally supported on a carrier. For example, to Patent Document 1, ruthenium is supported on the carrier is used as the rare earth oxide, the amount of ruthenium can be reduced, and the reaction temperature can be lowered is disclosed. However, Patent Document 1 in the manufacturing method of the ammonia, the ammonia in the case of manufacturing the lower pressure conditions of the ammonia is not satisfactory in yield. Therefore, the inventors of the present invention, the reduced La0.5Ce0.5O1.75 at 650°C and developed by a ruthenium catalyst carrier, excellent characteristics under a low pressure condition was reported (Non-Patent Document 4).
Patent Document 1, Non-Patent Document 4 and in addition, a variety of rare earth oxide carrier carrying the catalyst with ruthenium ammonia synthesis has been disclosed in various patents. As a typical example, JP-2-4, can be cited non-patent document 1-3. Patent Document 2 and Patent Document 4 is a lanthanoid oxide, praseodymium oxide is disclosed in Patent Document 3, Non-Patent Document 1 is a Ce oxide, has been disclosed as a carrier. Is the non-patent document 2, Ru, Ce, La hydroxide coprecipitation, drying, was activated, the catalyst of Ru/CeO2-La2O3 disclosed system.
Patent Document 1, 2, 4, including non-patent document 1 is in the literature of the prior art, the ruthenium catalyst used in the synthesis of ammonia on the surface of carrier particles can be present as Ru is described. If present as particles, have an average diameter greater than 5nm of the report (see Non-Patent Document 2), and, less than 2nm (Non-Patent Document 4) report. In addition, in Patent Document 3, and Ru the Nest shell structure has been described. On the other hand, the carrier will be, in non-patent document 3, supported Ru (La) - M-O Y (M is, Ca, Sr, Ba) when the ammonia synthesis activity of the catalyst, supported on a carrier before Ru for oxide, the sintering temperature of the oxide carrier and a large specific surface area is 450°C, the firing temperature was increased up to 650°C decrease in specific surface area of the carrier has been described. Also, in view of the high cost of Ru, Ru in the transition metal compound other than the carrier, for example Co supported on a catalyst for ammonia synthesis also has been proposed (for example, Non-Patent Document 5, Non-Patent Document 6 reference). However, in non-patent document 6, supported on the cobalt and barium oxide are disclosed in the Co-BaO/C, ammonia synthesis activity is low. Also, in non-patent document 5, rather than the metal oxide is calcium amide using a (Co/Ba-Ca 2 (NH2) )), 1mpa Co catalyst carried on the ammonia in the yield, a catalyst is supported on the Ru does not.
A catalyst for synthesizing the obtained synthetic activity is generally high. Is developed with respect to the ruthenium catalyst for ammonia synthesis, allow a higher yield of the high activity is continuously demanded. 1 Moles of nitrogen and 3 to 2 moles of ammonia from the hydrogen to be synthesized in the reaction equilibrium, the chemical equilibrium on the pressure conditions of the ammonia in order to improve the yield should be convenient. Therefore, instead of the 1mpa reaction, the reaction at a pressure greater than 1mpa ammonia may be considered to improve the yield. However, the ruthenium catalyst for ammonia synthesis of known, active catalyst poisoning by the hydrogen tends to decrease. Existing Ru-based catalyst is, the Haber, the Bosch method under low pressure conditions than high ammonia synthesis activity often for the purposes of aiming, high pressure conditions to improve the yield and is not suitable.
In addition, the catalyst is loaded into the synthesis reactor used must be periodically replaced, easy handling thereof can also be obtained. With respect to the ruthenium catalyst for ammonia synthesis, it is possible to improve ease of handling are also a continuing need.
Scope of claims (In Japanese)[請求項1]
一般式(6)の組成で示される金属元素を含む複合酸化物であって、Aの酸化物とXの酸化物との混合状態である複合酸化物
        A nX y  (6)
  (前記一般式(6)において、
    Aは、Sc,Y及びIII価のランタノイドからなる群より選ばれる元素を表し、
    Xは、Ca,Sr,Baからなる群から選ばれる元素を表し、
    nは0<n<1であり、
    yは0<y<1であり、
    n+y=1である)。

[請求項2]
一般式(7)の組成で示される金属元素を含む複合酸化物であって、Aの酸化物とXの酸化物との混合状態である複合酸化物
        A nX yO x  (7)
  (前記一般式(7)において、
    Aは、Sc,Y及びIII価のランタノイドからなる群より選ばれる元素を表し、
    Xは、Ca,Sr,Baからなる群から選ばれる元素を表し、
    nは0<n<1であり、
    yは0<y<1であり、
    n+y=1であり、
    xは複合酸化物が電気的に中性を保つのに必要な酸素原子の数を表わす)。

[請求項3]
前記AがSc,Y,La,Nd,Pm,Sm,Eu,Gd,Dy,Ho,Er,Tm及びLuからなる群より選ばれることを特徴とする請求項1又は2に記載の複合酸化物。

[請求項4]
前記AがLaであり、前記XがBaであることを特徴とする請求項1又は2に記載の複合酸化物。

[請求項5]
炭酸イオンの量が、前記Xに対して10mol%以下である請求項1又は2に記載の複合酸化物。

[請求項6]
前記Aの酸化物粒子の表面に前記Xの酸化物粒子が堆積してなることを特徴とする請求項5に記載の複合酸化物。

[請求項7]
一般式(6A)の組成で示される金属元素を含む複合酸化物であることを特徴とする請求項1に記載の複合酸化物
        A nX yM m  (6A)
  (前記一般式(6A)において、
    A及びXは請求項1で定義したとおりであり、
    Mは、周期表第1族元素、Ca,Sr,Baからなる群から選ばれる第2族元素、又はランタノイドのいずれかであり、かつ前記A及び前記Xと異なる元素を表し、
    nは0<n<1であり、
    yは0<y<1であり、
    mは0≦m<1であり、
    n+y+m=1である。)。

[請求項8]
前記複合酸化物が、正方晶又は立方晶の、固溶体を含む、請求項7に記載の複合酸化物。

[請求項9]
複合酸化物に含まれる各元素A、X、Mの少なくとも1つは、酸化物の状態における酸素の部分負電荷(-δ O)の値が0.50以上の強塩基性元素である、請求項7に記載の複合酸化物。

[請求項10]
複合酸化物に含まれる各元素の組成比をni(i=A、X、M、Oを含む複合酸化物中の全元素を示す)とし、各元素のサンダーソン電気陰性度をχi(i=A、X、M、Oを含む複合酸化物中の全元素を示す)としたときに、下記式(A)で示される酸素の部分負電荷の値(-δ O)が0.52以上である、請求項7に記載の複合酸化物。
 ((Π(χi ni))^(1/Σni)-5.21)/-4.75  ・・式(A)

[請求項11]
前記一般式(6A)におけるXはBaであって、前記複合酸化物に含まれる炭酸イオンの量が、Baに対して10mol%以下であることを特徴とする、請求項7に記載の複合酸化物。

[請求項12]
請求項1に記載の複合酸化物にコバルト粒子が担持されたことを特徴とする金属担持物。

[請求項13]
前記Aの酸化物及び前記Xの酸化物の微粒子からなる層を前記コバルト粒子上に有することを特徴とする請求項12に記載の金属担持物。

[請求項14]
H 2パルス化学吸着法により求めたCo分散度の値(D ads)と、TEM像から求めたCo粒子の平均粒子径から期待されるCo分散度の値(D TEM)との比が、
      0<D ads/D TEM<1
であること特徴とする請求項12に記載の金属担持物。

[請求項15]
前記複合酸化物上に担持された前記コバルト粒子の平均粒子径が100nm以下であることを特徴とする請求項12に記載の金属担持物。

[請求項16]
請求項12に記載の金属担持物を用いたことを特徴とするアンモニア合成用触媒。

[請求項17]
請求項12に記載の金属担持物の製造方法であって、
 前記Aを含むA前駆体、及び前記Xを含むX前駆体を混合して混合物を得る混合工程と、
 前記混合物を600℃以上の温度で焼成して複合酸化物からなる担体を得る焼成工程と、
 前記複合酸化物にコバルトを含む化合物を担持させて還元処理前担持物を調製する担持工程と、
 前記還元処理前担持物を400℃以上の温度で還元処理する還元工程と、を含むことを特徴とする金属担持物の製造方法。

[請求項18]
水素と窒素を触媒と接触させて、アンモニアを製造する方法であって、前記触媒が、請求項16に記載のアンモニア合成用触媒であることを特徴とするアンモニアの製造方法。
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • Inventor
  • NAGAOKA Katsutoshi
  • OGURA Yuta
  • SATO Katsutoshi
IPC(International Patent Classification)
Reference ( R and D project ) CREST Creation of Innovative Core Technology for Manufacture and Use of Energy Carriers from Renewable Energy AREA
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