JP2003277059A - Ceria-zirconia compound oxide - Google Patents
Ceria-zirconia compound oxideInfo
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- JP2003277059A JP2003277059A JP2002080890A JP2002080890A JP2003277059A JP 2003277059 A JP2003277059 A JP 2003277059A JP 2002080890 A JP2002080890 A JP 2002080890A JP 2002080890 A JP2002080890 A JP 2002080890A JP 2003277059 A JP2003277059 A JP 2003277059A
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- composite oxide
- ceria
- osc
- zirconia
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、1000℃以上の酸化
性雰囲気下でも相分離が抑制され、高い酸素吸蔵放出能
（以下 OSCという）を有するセリア−ジルコニア系複合
酸化物に関する。TECHNICAL FIELD The present invention relates to a ceria-zirconia-based composite oxide having a high oxygen storage / release capacity (hereinafter referred to as OSC) in which phase separation is suppressed even in an oxidizing atmosphere at 1000 ° C. or higher.
【０００２】[0002]
【従来の技術】従来より自動車の排ガス浄化用触媒とし
て、排ガス中のCO及びHCの酸化とNOxの還元とを同時に
行って浄化する三元触媒が用いられている。このような
三元触媒としては、例えばコーディエライトなどからな
る耐熱性ハニカム基材にγ-Al2O3からなる担体層を形成
し、その担体層に白金（Pt）やロジウム（Rh)などの触
媒金属を担持させたものが広く知られている。2. Description of the Related Art Conventionally, as a catalyst for purifying exhaust gas of automobiles, a three-way catalyst has been used which purifies the exhaust gas by simultaneously oxidizing CO and HC and reducing NO x . As such a three-way catalyst, for example, a carrier layer made of γ-Al 2 O 3 is formed on a heat-resistant honeycomb substrate made of cordierite or the like, and platinum (Pt) or rhodium (Rh) is formed on the carrier layer. It is widely known that the above catalyst metal is supported.
【０００３】ところで排ガス浄化用触媒に用いられる担
体の条件としては、比表面積が大きく耐熱性が高いこと
が挙げられ、一般には Al2O3、SiO2、ZrO2、TiO2などが
用いられることが多い。また OSCをもつCeO2を助触媒と
して併用することで、排ガスの雰囲気変動を緩和するこ
とも行われている。The condition of the carrier used for the exhaust gas purifying catalyst is that it has a large specific surface area and high heat resistance. Generally, Al 2 O 3 , SiO 2 , ZrO 2 , TiO 2 and the like are used. There are many. Also, by using CeO 2 with OSC as a co-catalyst together, it is possible to mitigate the atmospheric fluctuation of exhaust gas.
【０００４】ところが従来の排ガス浄化用触媒では、 8
00℃を超えるような高温にさらされると、シンタリング
による担体の比表面積の低下、触媒金属の粒成長が生
じ、さらにはCeO2のもつ OSCも低下するために、浄化性
能が著しく低下するという不具合があった。However, in the conventional exhaust gas purifying catalyst,
When exposed to a high temperature of more than 00 ° C, the specific surface area of the carrier decreases due to sintering, the grain growth of the catalytic metal occurs, and the OSC of CeO 2 also decreases, resulting in a marked decrease in purification performance. There was a problem.
【０００５】また近年の排ガス規制の強化により、エン
ジン始動からごく短い時間にも排ガスを浄化する必要性
がきわめて高くなっている。そのためには、より低温で
触媒を活性化し、排出規制成分を浄化しなければならな
い。中でもPtをCeO2に担持した触媒は、低温からCOを浄
化する性能に長けている。このような触媒を用いれば、
COが低温で着火されることによってPtのCO吸着被毒が緩
和され、HCの着火性が向上する。また、これによって触
媒表面の暖機が促進されるため、低温域からHCを浄化す
ることができる。さらに、この触媒では、水性ガスシフ
ト反応によって低温域でH2が生成されるため、そのH2と
NOx との反応により低温域からNOx を還元浄化すること
ができる。Further, due to the recent tightening of exhaust gas regulations, it becomes extremely necessary to purify exhaust gas within a very short time after the engine is started. For that purpose, the catalyst must be activated at a lower temperature to purify the emission control component. Above all, the catalyst in which Pt is supported on CeO 2 is excellent in the ability to purify CO from a low temperature. With such a catalyst,
By igniting CO at a low temperature, CO adsorption poisoning of Pt is mitigated, and the ignitability of HC is improved. Further, this promotes warm-up of the catalyst surface, so that HC can be purified from a low temperature range. Furthermore, in this catalyst, since the H 2 is generated in a low temperature region by water gas shift reaction, and its H 2
It is possible to reduce and purify NO x from the low temperature zone by reaction with NO x.
【０００６】しかし従来のCeO2にPtなどを担持した触媒
においては、実際の排ガス中における耐久性に乏しく、
熱によってCeO2がシンタリングしてしまい実用的ではな
い。実際の排ガス中で使用するためには、CeO2の性質を
失うことなく耐熱性を向上させる必要性がある。またCe
O2のシンタリングに伴ってPtに粒成長が生じ活性が低下
するため、担体上のPtの安定化が求められている。However, in the conventional catalyst in which Pt is supported on CeO 2 , the durability in actual exhaust gas is poor,
The heat causes CeO 2 to sinter, which is not practical. For use in actual exhaust gas, it is necessary to improve the heat resistance without losing the properties of CeO 2 . Also Ce
Stabilization of Pt on the carrier is required because grain growth of Pt occurs due to O 2 sintering and activity decreases.
【０００７】また担体にCeO2を含む三元触媒でも、高温
にさらされるとCeO2によって発現される OSCが低下す
る。これはCeO2のシンタリング及び担持されている貴金
属の粒成長と、貴金属の酸化、RhのCeO2への固溶などが
原因である。そして OSCが低い（CeO2量が少ない）触媒
においては、変動する雰囲気に貴金属がさらされやす
く、貴金属の劣化（凝集や固溶）がさらに促進されてし
まう。Even with a three-way catalyst containing CeO 2 as a carrier, the OSC expressed by CeO 2 decreases when exposed to high temperatures. This is due to sintering of CeO 2 and grain growth of the precious metal supported, oxidation of the precious metal, and solid solution of Rh in CeO 2 . And in a catalyst with a low OSC (a small amount of CeO 2 ), the noble metal is easily exposed to the changing atmosphere, and the deterioration (aggregation or solid solution) of the noble metal is further promoted.
【０００８】そこで特開平8-215569号公報には、金属ア
ルコキシドから調製されたCeO2−ZrO2複合酸化物を用い
る技術が開示されている。金属アルコキシドからゾルゲ
ル法により調製されたCeO2−ZrO2複合酸化物は、CeとZr
とが原子又は分子レベルで複合化されて固溶体となって
いるため、耐熱性が向上し初期から耐久後まで高い OSC
が確保される。Japanese Unexamined Patent Publication (Kokai) No. 8-215569 discloses a technique using a CeO 2 --ZrO 2 composite oxide prepared from a metal alkoxide. CeO 2 -ZrO 2 composite oxide prepared by sol-gel method from metal alkoxide is Ce and Zr
Since and are compounded at the atomic or molecular level to form a solid solution, the heat resistance improves and the OSC is high from the beginning to the end of durability.
Is secured.
【０００９】このような複合酸化物は、アルコキシド
法、共沈法などにより複数の金属元素を含む酸化物前駆
体を調製し、それを焼成することで製造することができ
る。中でも共沈法は、アルコキシド法などに比べて原料
コストが安価であるため、得られる複合酸化物も安価と
なる利点があり、複合酸化物の製造に広く用いられてい
る。Such a complex oxide can be produced by preparing an oxide precursor containing a plurality of metal elements by an alkoxide method, a coprecipitation method or the like, and firing it. Among them, the coprecipitation method has a merit that the raw material cost is lower than that of the alkoxide method and the like, and thus the obtained composite oxide is also inexpensive, and is widely used in the production of the composite oxide.
【００１０】ところが上記した特開平8-215569号公報に
記載の複合酸化物では、 OSCがまだ不充分であり、さら
なる OSCの向上が求められている。そこで特開平11−16
5067号公報には、セリウム（ III）塩とジルコニウム
（IV）塩を含む溶液から共沈法によって沈殿を形成し、
その沈殿を不活性雰囲気又は非酸化性雰囲気下で 800〜
1000℃に加熱保持する方法が記載されている。この方法
によれば、得られる複合酸化物はパイロクロア相に帰属
するＸ線回折ピークを有し、高い OSCを示す。However, the composite oxide described in Japanese Patent Application Laid-Open No. 8-215569 mentioned above is still insufficient in OSC, and further improvement in OSC is required. Therefore, JP 11-16
No. 5067 discloses that a precipitate is formed by a coprecipitation method from a solution containing a cerium (III) salt and a zirconium (IV) salt,
800 ~ under an inert or non-oxidizing atmosphere
A method of heating and holding at 1000 ° C is described. According to this method, the obtained composite oxide has an X-ray diffraction peak attributed to the pyrochlore phase and exhibits a high OSC.
【００１１】[0011]
【発明が解決しようとする課題】特開平11−165067号公
報に記載の方法によれば、確かに高い OSCを有するCeO2
−ZrO2複合酸化物が得られる。しかしながらこのCeO2−
ZrO2複合酸化物では、原子比Zr／Ceが１以上である場合
には、パイロクロア相の形成が困難であり、価数変化に
寄与するセリウムイオンの割合が少なくなるという不具
合がある。特に排ガス浄化用触媒の担体として用いる場
合には、排ガス中のSOx と担体との反応による活性低下
を抑制するためにCeO2量が少ないCeO2−ZrO2複合酸化物
とすることが望ましいが、上記した不具合のために、原
子比Zr／Ceが１以上である場合には十分な OSCが得られ
ないという問題があった。According to the method described in Japanese Patent Laid-Open No. 11-165067, it is possible to obtain CeO 2 having a high OSC.
A -ZrO 2 composite oxide is obtained. However, this CeO 2 −
In the ZrO 2 composite oxide, when the atomic ratio Zr / Ce is 1 or more, it is difficult to form a pyrochlore phase, and there is a problem that the proportion of cerium ions contributing to valence change is small. Especially when used as a carrier of an exhaust gas purifying catalyst, it is desirable to use a CeO 2 -ZrO 2 composite oxide having a small amount of CeO 2 in order to suppress the activity decrease due to the reaction between SO x and the carrier in the exhaust gas. However, due to the above problems, there was a problem that sufficient OSC could not be obtained when the atomic ratio Zr / Ce was 1 or more.
【００１２】また二元系のCeO2−ZrO2複合酸化物では、
1000℃以上の高温の酸化性雰囲気下で相分離が生じ、耐
熱性が十分でないという問題もある。Further, in the binary CeO 2 --ZrO 2 composite oxide,
There is also a problem that the heat resistance is not sufficient because phase separation occurs in an oxidizing atmosphere at a high temperature of 1000 ° C or higher.
【００１３】本発明はこのような事情に鑑みてなされた
ものであり、高い耐熱性を有するとともに、原子比Zr／
Ceが１以上である場合でも十分な OSCが発現されるセリ
ア−ジルコニア系複合酸化物を提供することを目的とす
る。The present invention has been made in view of such circumstances and has a high heat resistance and an atomic ratio Zr /
An object of the present invention is to provide a ceria-zirconia-based composite oxide that exhibits a sufficient OSC even when Ce is 1 or more.
【００１４】[0014]
【課題を解決するための手段】上記課題を解決できる本
発明のセリア−ジルコニア系複合酸化物の特徴は、CeO2
と、ZrO2と、希土類元素，アルカリ土類元素及び遷移元
素から選ばれる少なくとも一種の添加元素の酸化物と、
からなり、セリウムイオン及びジルコニウムイオンが規
則配列した規則相をもつことにある。The feature of the ceria-zirconia-based composite oxide of the present invention that can solve the above-mentioned problems is that CeO 2
And ZrO 2, and an oxide of at least one additive element selected from rare earth elements, alkaline earth elements and transition elements,
And has a regular phase in which cerium ions and zirconium ions are regularly arranged.
【００１５】添加元素は全金属元素中に10モル％以下の
範囲で含まれていることが望ましい。また添加元素はイ
ットリウムであることが特に望ましい。The additive element is preferably contained in the total metal element in an amount of 10 mol% or less. It is particularly desirable that the additional element is yttrium.
【００１６】[0016]
【発明の実施の形態】通常の二元系のCeO2−ZrO2複合酸
化物は固溶体を形成しているが、単位格子内におけるセ
リウムイオンとジルコニウムイオンの配列に規則性はな
い。 OSCが発現される機構は、単位格子内のセリウムイ
オンが３価と４価の価数変化を起こす際に電気的中性の
原理によって酸素原子が放出されるものである。この際
に放出される酸素は、バルクの場合には４つのジルコニ
ウムイオンに配位された酸素原子であると考えられてい
る。BEST MODE FOR CARRYING OUT THE INVENTION Although a normal binary CeO 2 -ZrO 2 composite oxide forms a solid solution, there is no regularity in the arrangement of cerium ions and zirconium ions in a unit cell. The mechanism by which OSC is expressed is that oxygen atoms are released by the principle of electrical neutrality when the cerium ion in the unit cell undergoes trivalent and tetravalent valence changes. In the case of bulk, oxygen released at this time is considered to be oxygen atoms coordinated with four zirconium ions.
【００１７】したがってセリウムイオンとジルコニウム
イオンの配列に規則性がない通常のCeO2−ZrO2複合酸化
物では、ジルコニウムイオンに対して４配位した酸素原
子の数が少ないこと、並びにセリウムイオンが４価から
３価へ価数変化する際にイオン半径が0.86Åから1.15Å
に拡大することによって格子に歪みが生じるため酸素原
子が放出されにくいこと、などの理由により、Ceの含有
率から算出される理論限界値よりはるかに少ない OSCし
か得られない。Therefore, in a normal CeO 2 -ZrO 2 composite oxide in which the arrangement of cerium ions and zirconium ions is not regular, the number of oxygen atoms tetracoordinated with zirconium ions is small and the number of cerium ions is 4. The ionic radius changes from 0.86Å to 1.15Å when the valence changes from three to three
Because of the strain in the lattice caused by the expansion to the oxygen atom, it is difficult to release oxygen atoms, and the OSC is much lower than the theoretical limit calculated from the Ce content.
【００１８】そこで特開平11−165067号公報に記載の方
法などにより二元系のCeO2−ZrO2複合酸化物を製造すれ
ば、得られるCeO2−ZrO2複合酸化物はパイロクロア相に
帰属するＸ線回折ピークを有し、セリウムイオンとジル
コニウムイオンとが規則配列した規則相をもつ。これに
より価数変化に寄与するセリウムイオンの割合が多くな
り、理論限界値に近い高い OSCが発現される。Therefore, if a binary CeO 2 --ZrO 2 composite oxide is produced by the method described in JP-A-11-165067, the obtained CeO 2 --ZrO 2 composite oxide belongs to the pyrochlore phase. It has an X-ray diffraction peak and has an ordered phase in which cerium ions and zirconium ions are regularly arranged. As a result, the proportion of cerium ions that contribute to valence change increases, and a high OSC close to the theoretical limit is developed.
【００１９】ところがこのような二元系のCeO2−ZrO2複
合酸化物では、原子比Zr／Ceが１以上であるようなZrO2
リッチの場合には、遊離したZrO2相が増加するのみでZr
O2リッチなパイロクロア相の形成が困難であり、ZrO2リ
ッチ組成にする意味はない。また1000℃以上の高温の酸
化性雰囲気下で相分離が生じ、CeO2リッチ相とZrO2リッ
チ相に分離するため、価数変化に寄与するセリウムイオ
ンの割合が少なくなりOSCが低下するという問題があ
る。このように相分離した場合には、1100℃以上の高温
の還元性雰囲気下で長時間処理することで、二相分離し
た固溶体相が単一の固溶体相となり、さらに規則相が回
復するが、相分離と再固溶の過程におけるシンタリング
によって比表面積が減少し活性が低下するという不具合
がある。However, in such a binary CeO 2 --ZrO 2 composite oxide, ZrO 2 having an atomic ratio Zr / Ce of 1 or more is used.
In the case of rich, only the free ZrO 2 phase increases and the Zr
It is difficult to form an O 2 -rich pyrochlore phase, and there is no point in using a ZrO 2 -rich composition. In addition, phase separation occurs in an oxidizing atmosphere at a high temperature of 1000 ° C or higher, and it separates into a CeO 2 rich phase and a ZrO 2 rich phase, so the proportion of cerium ions that contribute to valence change decreases and the OSC decreases. There is. In the case of phase separation in this way, by performing a long-time treatment under a high temperature reducing atmosphere of 1100 ° C. or higher, the solid solution phase separated into two phases becomes a single solid solution phase, and the ordered phase is recovered, There is a problem that the specific surface area is decreased and the activity is decreased due to sintering in the process of phase separation and re-solid solution.
【００２０】そこで本発明のセリア−ジルコニア系複合
酸化物では、CeO2及びZrO2に加えて、希土類元素，アル
カリ土類元素及び遷移元素から選ばれる少なくとも一種
の添加元素の酸化物をさらに含有し、セリウムイオン及
びジルコニウムイオンが規則配列した規則相を構成して
いる。理由は不明であるが、この組成とすることで、本
発明のセリア−ジルコニア系複合酸化物は原子比Zr／Ce
が１以上の範囲でも規則相が形成される。したがって原
子比Zr／Ceが１以上の範囲でも価数変化に寄与するセリ
ウムイオンの割合が多くなり、理論限界値に近い高い O
SCが発現される。Therefore, the ceria-zirconia-based composite oxide of the present invention further contains, in addition to CeO 2 and ZrO 2 , an oxide of at least one additive element selected from rare earth elements, alkaline earth elements and transition elements. , Cerium ions and zirconium ions form a regular phase. Although the reason is not clear, by adopting this composition, the ceria-zirconia-based composite oxide of the present invention has an atomic ratio of Zr / Ce.
A regular phase is formed even in the range of 1 or more. Therefore, even if the atomic ratio Zr / Ce is in the range of 1 or more, the proportion of cerium ions contributing to the valence change increases, and a high O 2 value close to the theoretical limit value is obtained.
SC is expressed.
【００２１】また本発明のセリア−ジルコニア系複合酸
化物では、理由は不明であるが、1000℃以上の酸化性雰
囲気下でも相分離せず単一の結晶相が維持される。その
ため1000℃以上の酸化性雰囲気で規則相が一旦不規則相
からなる固溶体相へ変態しても、固溶体相が二相に分離
しないため還元性雰囲気で容易に規則相が回復でき、相
分離と再結合に伴うシンタリングも起こさないため、比
表面積も維持できる。In the ceria-zirconia-based composite oxide of the present invention, although the reason is unknown, a single crystal phase is maintained without phase separation even in an oxidizing atmosphere at 1000 ° C. or higher. Therefore, even if the ordered phase once transforms into a solid solution phase consisting of a disordered phase in an oxidizing atmosphere of 1000 ° C or higher, the ordered phase can be easily recovered in a reducing atmosphere because the solid solution phase does not separate into two phases, and phase separation and Since sintering due to recombination does not occur, the specific surface area can be maintained.
【００２２】なお本発明にいう規則相とは、セリウムイ
オン及びジルコニウムイオンが規則配列した相であり、
酸素原子が抜けた状態ではパイロクロア相に相当する。
本発明のセリア−ジルコニア系複合酸化物の結晶構造
は、図１に示すような構造をなし、セリウムイオン及び
ジルコニウムイオンが規則配列していると考えられる。
添加元素は、この結晶構造内部の陽イオンのサイトにラ
ンダムに含まれていると考えられる。The ordered phase referred to in the present invention is a phase in which cerium ions and zirconium ions are regularly arranged,
It corresponds to the pyrochlore phase in the state where oxygen atoms are lost.
The crystal structure of the ceria-zirconia-based composite oxide of the present invention has a structure as shown in FIG. 1, and it is considered that cerium ions and zirconium ions are regularly arranged.
It is considered that the additive element is randomly included in the cation sites inside the crystal structure.
【００２３】添加元素は希土類元素，アルカリ土類元素
及び遷移元素から選ばれる少なくとも一種であり、例え
ばＹ，Ca，Mg，Ba，Feが好ましく例示される。中でもＹ
が特に好ましい元素である。この添加元素は、全金属元
素中に10モル％以下の範囲で含まれていることが望まし
く、５〜10モル％の範囲が特に好ましい。添加元素が10
モル％を超えると上記作用が飽和するとともに、 OSCが
低下する。また５モル％未満では、上記作用の発現の程
度が低く実用的でない。The additive element is at least one selected from rare earth elements, alkaline earth elements and transition elements, and Y, Ca, Mg, Ba and Fe are preferably exemplified. Above all, Y
Is a particularly preferred element. This additive element is preferably contained in the total metal elements in the range of 10 mol% or less, and particularly preferably in the range of 5 to 10 mol%. 10 additional elements
When it exceeds mol%, the above-mentioned action is saturated and OSC is lowered. On the other hand, if it is less than 5 mol%, the degree of the above-mentioned action is low and not practical.
【００２４】本発明のセリア−ジルコニア系複合酸化物
におけるセリウムイオンとジルコニウムイオンの構成比
率は、Ce／Zr原子比が１／９〜９／１の範囲が実用的で
あり、３／７〜７／３とするのが特に好ましい。セリウ
ムイオンがこの範囲より少ないと OSCの絶対量が不足
し、ジルコニウムイオンがこの範囲より少ないと耐熱安
定性が低下するとともに使用時にSOx との反応によって
活性が低下してしまう。The composition ratio of cerium ions and zirconium ions in the ceria-zirconia-based composite oxide of the present invention is practical when the Ce / Zr atomic ratio is in the range of 1/9 to 9/1, and 3/7 to 7 It is particularly preferable that it is / 3. If the amount of cerium ions is less than this range, the absolute amount of OSC will be insufficient, and if the amount of zirconium ions is less than this range, the thermal stability will decrease and the activity will decrease due to the reaction with SO x during use.
【００２５】なお本発明のセリア−ジルコニア系複合酸
化物は、高温の酸化性雰囲気下で規則相がランダム相に
相変化する場合があるが、 800〜1200℃の還元性雰囲気
での短時間の処理によって容易に規則相が回復し、高い
OSCが回復する。したがって比表面積の減少が抑制され
る。In the ceria-zirconia-based composite oxide of the present invention, the ordered phase may change to a random phase in an oxidizing atmosphere at a high temperature, but a short time in a reducing atmosphere at 800 to 1200 ° C. The order phase is easily recovered by the treatment and is high
OSC recovers. Therefore, the reduction of the specific surface area is suppressed.
【００２６】本発明のセリア−ジルコニア系複合酸化物
を製造するには、セリウム化合物と、ジルコニウム化合
物と、添加元素の化合物の溶液に沈殿剤を添加して共沈
法により沈殿物を生成し、得られた沈殿物を焼成した
後、還元性雰囲気中にて 800〜1200℃で加熱保持する還
元処理を行う方法で製造することができる。To produce the ceria-zirconia-based composite oxide of the present invention, a precipitant is added to a solution of a cerium compound, a zirconium compound, and a compound of an additional element to form a precipitate by a coprecipitation method, It can be produced by a method in which the obtained precipitate is calcined and then subjected to a reduction treatment in which it is heated and held at 800 to 1200 ° C. in a reducing atmosphere.
【００２７】セリウム化合物，ジルコニウム化合物及び
添加元素の化合物としては、硝酸塩、硫酸塩、塩化物な
どの水溶性化合物を用いることができる。また沈殿剤
は、アンモニア、アルカリ金属の水酸化物、アルカリ金
属の炭酸塩などを用いることができる。セリウム化合
物，ジルコニウム化合物及び添加元素の化合物が共存す
る混合水溶液から共沈させた後に焼成してもよいし、Ce
O2前駆体の沈殿，ZrO2前駆体の沈殿，添加元素の酸化物
前駆体の沈殿をそれぞれ形成し、この３種類の沈殿を混
合してから焼成することもできる。As the cerium compound, the zirconium compound and the compound of the additional element, water-soluble compounds such as nitrates, sulfates and chlorides can be used. As the precipitant, ammonia, hydroxide of alkali metal, carbonate of alkali metal, or the like can be used. It may be coprecipitated from a mixed aqueous solution in which a cerium compound, a zirconium compound, and a compound of an additional element coexist, and then baked.
It is also possible to form a precipitate of the O 2 precursor, a precipitate of the ZrO 2 precursor, and a precipitate of the oxide precursor of the additional element, mix these 3 kinds of precipitates, and then bake.
【００２８】沈殿の析出方法には様々な調節方法があ
り、アンモニア水などを瞬時に添加し強撹拌する方法
や、過酸化水素などを加えることで酸化物前駆体の沈殿
し始めるpHを調節した後、アンモニア水などで沈殿を析
出させる方法などがある。またアンモニア水などで中和
させる際にかかる時間を充分に長くし、好ましくは10分
以上で中和させる方法や、pHをモニターしながら段階的
に中和する又は所定のpHに保つような緩衝溶液を添加す
る方法などがある。There are various methods for controlling the precipitation. For example, ammonia water is added instantly and vigorously stirred, or hydrogen peroxide is added to adjust the pH at which the oxide precursor starts to precipitate. After that, there is a method of depositing a precipitate with aqueous ammonia. Also, the time required for neutralization with ammonia water, etc. should be sufficiently long, preferably 10 minutes or more, or a buffer that neutralizes stepwise while monitoring the pH or maintains a predetermined pH. There is a method of adding a solution.
【００２９】沈殿を生成する過程において、常に1000／
秒以上のせん断速度で撹拌することが望ましい。これに
より生成する酸化物前駆体の粒径を微細化することがで
き、複合酸化物の粒径をより小さくすることができる。
なお酸化物前駆体の粒径は３μｍ以下とすることが望ま
しい。粒径がこれより大きくなると、生成する複合酸化
物の粒径が大きくなりすぎて比表面積の低下により活性
が低下してしまう。In the process of producing a precipitate, 1000 /
It is desirable to stir at a shear rate of at least seconds. As a result, the particle size of the produced oxide precursor can be made finer, and the particle size of the composite oxide can be made smaller.
The particle size of the oxide precursor is preferably 3 μm or less. If the particle size is larger than this, the particle size of the produced composite oxide becomes too large and the specific surface area decreases, resulting in a decrease in activity.
【００３０】沈殿物の焼成前に、水又は水を含む溶液を
分散媒とした懸濁状態または系内に水が充分に存在する
状態で、沈殿物の熟成処理を行うことが望ましい。この
熟成処理を行うことによって、得られる複合酸化物の粒
径が揃えられるため、粒成長の駆動力の一つである表面
分圧が揃い、還元処理時の粒成長をさらに抑制すること
ができる。Before calcination of the precipitate, it is desirable to perform the aging treatment of the precipitate in a suspension state using water or a solution containing water as a dispersion medium or in a state where water is sufficiently present in the system. By performing this aging treatment, the grain sizes of the obtained composite oxide are made uniform, so that the surface partial pressure, which is one of the driving forces for grain growth, is made uniform and the grain growth during the reduction treatment can be further suppressed. .
【００３１】熟成処理は、系内に水分が充分に存在して
いる状態で、沈殿を含む溶液ごとオートクレーブなどの
耐圧、耐熱容器中で加熱して行い、その後溶媒を蒸発さ
せ、焼成することで行うことができる。あるいは濾別さ
れた沈殿物を水蒸気の存在下で焼成してもよい。この場
合は、飽和水蒸気雰囲気で焼成することが好ましく、10
0〜 200℃で、さらに好ましくは 100〜 150℃で行う水
熱処理が特に望ましい。 100℃未満の加温では熟成の促
進効果が小さく、熟成に要する時間が長大となる。また
200℃より高い温度では、10気圧以上に耐えうる合成装
置が必要となり、設備コストが高くなる。The aging treatment is carried out by heating the entire solution containing the precipitate in a pressure-resistant, heat-resistant container such as an autoclave in a state where water is sufficiently present in the system, and then evaporating the solvent and baking it. It can be carried out. Alternatively, the filtered precipitate may be calcined in the presence of steam. In this case, it is preferable to fire in a saturated steam atmosphere,
A hydrothermal treatment carried out at 0 to 200 ° C, more preferably 100 to 150 ° C is particularly desirable. If the heating temperature is lower than 100 ° C, the aging-promoting effect is small and the aging time becomes long. Also
At temperatures higher than 200 ° C, a synthesizing device capable of withstanding 10 atm or more is required, resulting in high facility cost.
【００３２】上記した熟成処理を行った場合には、加温
の熱によって溶解・再析出が促進されるとともに粒子の
成長が生じる。この場合は、酸塩の全てを中和できる当
量以上の塩基で中和することが望ましい。これにより酸
化物前駆体がより均一に熟成され、細孔が効果的に形成
されるとともに、本発明のセリア−ジルコニア系複合酸
化物の生成がさらに促進される。When the above-mentioned aging treatment is carried out, the heat of heating accelerates the dissolution / reprecipitation and causes the growth of particles. In this case, it is desirable to neutralize all of the acid salt with an equivalent amount or more of a base capable of neutralizing the acid salt. Thereby, the oxide precursor is aged more uniformly, pores are effectively formed, and the production of the ceria-zirconia-based composite oxide of the present invention is further promoted.
【００３３】沈殿を焼成した後、還元性雰囲気中にて 8
00〜1200℃で加熱保持することによって、セリウムイオ
ン及びジルコニウムイオンが規則配列した規則相をもつ
本発明のセリア−ジルコニア系複合酸化物が得られる。
加熱保持温度が 800℃より低いと規則相の生成が困難と
なり OSCが低下する。また1200℃より高くなると比表面
積の低下が著しいため好ましくない。After firing the precipitate, it is heated in a reducing atmosphere for 8 hours.
By heating and holding at 00 to 1200 ° C., the ceria-zirconia-based composite oxide of the present invention having an ordered phase in which cerium ions and zirconium ions are regularly arranged can be obtained.
If the heating and holding temperature is lower than 800 ° C, it is difficult to form the ordered phase and the OSC decreases. On the other hand, when the temperature is higher than 1200 ° C, the specific surface area is significantly decreased, which is not preferable.
【００３４】還元性雰囲気は、不活性ガス雰囲気又は非
酸化性雰囲気とすることもできるが、H2，COなどの還元
性ガスを積極的に含む雰囲気とすることが望ましい。還
元性ガスを含まないと、結晶格子からの酸素原子の脱離
が充分に速く進行しないため規則相が十分に生成でき
ず、高い OSCが得られない場合がある。The reducing atmosphere may be an inert gas atmosphere or a non-oxidizing atmosphere, but it is desirable that the reducing atmosphere be positively containing a reducing gas such as H 2 or CO. If the reducing gas is not included, the desorption of oxygen atoms from the crystal lattice does not proceed fast enough, so that a regular phase cannot be generated sufficiently and high OSC may not be obtained.
【００３５】なお上記還元処理の後に酸化性雰囲気下に
て処理し、さらに還元処理を行うことも好ましい。理由
は不明であるが、これにより OSCがさらに向上すること
がわかっている。After the reduction treatment, it is also preferable to perform the treatment in an oxidizing atmosphere and further perform the reduction treatment. For unknown reasons, we know that this will further improve OSC.
【００３６】本発明のセリア−ジルコニア系複合酸化物
は、自らを担体として貴金属を担持することにより、自
動車などの排ガス浄化用触媒とすることができる。貴金
属としては、Pt，Rh，Pd，Ir，Ruなどから一種又は複数
種選択して用いることができ、その担持量は従来の排ガ
ス浄化用触媒と同様でよい。また担持方法も、吸着担持
法、吸水担持法など従来の担持法を利用することができ
る。貴金属の担持により、低温域における OSCが著しく
増大する。The ceria-zirconia-based composite oxide of the present invention can be used as an exhaust gas purifying catalyst for automobiles by supporting a noble metal with itself as a carrier. As the noble metal, one or more kinds selected from Pt, Rh, Pd, Ir, Ru and the like can be selected and used, and the supported amount thereof may be the same as that of the conventional exhaust gas purifying catalyst. As the supporting method, a conventional supporting method such as an adsorption supporting method or a water absorption supporting method can be used. The OSC in the low temperature range remarkably increases due to the loading of the noble metal.
【００３７】[0037]
【実施例】以下、実施例及び比較例により本発明を具体
的に説明する。EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples.
【００３８】（実施例１）所定濃度の硝酸セリウム（ I
II）の水溶液と、所定濃度のオキシ硝酸ジルコニウムの
水溶液及び所定濃度の硝酸イットリウムの水溶液をそれ
ぞれ調製し、この３種の水溶液とセリウムイオンの 1.1
倍モルのH2O2を含む過酸化水素水を混合して充分に撹拌
した。Example 1 Cerium nitrate (I
II), an aqueous solution of zirconium oxynitrate with a predetermined concentration, and an aqueous solution of yttrium nitrate with a predetermined concentration were prepared, and these three types of aqueous solutions and cerium ion 1.1 were prepared.
Hydrogen peroxide solution containing double mole of H 2 O 2 was mixed and stirred sufficiently.
【００３９】この混合水溶液に全ての硝酸根を中和でき
る量の 1.2倍モルの NH3を含むアンモニア水を添加し、
メカニカルスターラー及びホモジナイザで10分間撹拌し
た。ホモジナイザによれば、 1000／秒以上のせん断速
度で撹拌される。得られた共沈物（酸化物前駆体）を濾
過・洗浄し、大気中にて 300℃で３時間乾燥し、さらに
500℃で１時間焼成した。Ammonia water containing 1.2 times the molar amount of NH 3 capable of neutralizing all nitrate radicals was added to this mixed aqueous solution,
Stir for 10 minutes with a mechanical stirrer and homogenizer. According to the homogenizer, stirring is performed at a shear rate of 1000 / sec or more. The obtained coprecipitate (oxide precursor) is filtered and washed, dried in air at 300 ° C. for 3 hours, and further
It was baked at 500 ° C. for 1 hour.
【００４０】得られた酸化物粉末をCO気流中にて1200℃
で５時間還元処理し、大気中にて 500℃で１時間処理し
て、本実施例のセリア−ジルコニア系複合酸化物粉末を
調製した。なお各水溶液の混合比率を変化させ、イット
リウムイオンはそれぞれ７モル％一定で、ジルコニウム
イオンのモル比（Zr／（Ce＋Zr））が 0.0〜 1.0の間で
それぞれ異なる複数種のセリア−ジルコニア系複合酸化
物粉末を調製した。また大気中にて 500℃で１時間処理
したのは、還元処理により抜けた酸素を結晶構造に戻
し、酸化状態での安定な結晶構造を同定するためであ
る。The obtained oxide powder is heated to 1200 ° C. in a CO stream.
Was treated for 5 hours at 500 ° C. in the atmosphere for 1 hour to prepare a ceria-zirconia-based composite oxide powder of this example. It should be noted that, by changing the mixing ratio of each aqueous solution, the yttrium ion is kept constant at 7 mol% and the zirconium ion molar ratio (Zr / (Ce + Zr)) varies from 0.0 to 1.0. The product powder was prepared. Further, the treatment at 500 ° C. for 1 hour in the atmosphere is for returning the oxygen released by the reduction treatment to the crystal structure and for identifying the stable crystal structure in the oxidized state.
【００４１】次に、得られたそれぞれの複合酸化物粉末
に所定濃度のジニトロジアンミン白金水溶液の所定量を
含浸させ、蒸発乾固後 300℃で３時間焼成してPtを担持
してそれぞれの触媒粉末を調製した。Ptの担持量は１重
量％である。Next, each of the obtained composite oxide powders was impregnated with a predetermined amount of a dinitrodiammineplatinum aqueous solution of a predetermined concentration, evaporated to dryness, and calcined at 300 ° C. for 3 hours to support Pt to support each catalyst. A powder was prepared. The loading amount of Pt is 1% by weight.
【００４２】それぞれの触媒粉末15mgを秤量し、H2を20
％含むN2ガスと、O2を50％含むN2ガスとを交互に流しな
がら、 500℃における試料の酸化還元を繰り返し行い、
生じる重量変化を熱重量分析を用いて測定することによ
って OSCを求めた。結果を Total OSCとして図２に示
す。また得られた OSCをセリウム量についてそれぞれ処
理し、セリウム元素１モル当たりの OSCを Partial OSC
として図３に示す。さらに得られたそれぞれの複合酸化
物粉末のＸ線回折チャートを図４に示す。なお図３にお
ける破線は、全てのセリウム元素が４価から３価に価数
変化した場合の OSCの理論限界値である。15 mg of each catalyst powder was weighed, and H 2 was added to 20 mg.
And N 2 gas containing%, while flowing O 2 alternating with N 2 gas containing 50% repeats the redox of the sample at 500 ° C.,
The OSC was determined by measuring the resulting weight change using thermogravimetric analysis. Figure 2 shows the result as Total OSC. Also, the obtained OSCs are treated for each amount of cerium, and the OSC per mol of cerium element is the Partial OSC
As shown in FIG. Further, an X-ray diffraction chart of each of the obtained composite oxide powders is shown in FIG. The broken line in Fig. 3 is the theoretical limit value of OSC when all cerium elements change their valence from tetravalent to trivalent.
【００４３】（実施例２）実施例１で調製された酸化物
粉末をCO気流中にて1200℃で５時間還元処理し、大気中
にて1200℃で５時間処理し、次いでCO気流中にて1200℃
で５時間還元処理し、さらに大気中にて 500℃で１時間
処理したこと以外は実施例１と同様にして、複数種の複
合酸化物粉末を調製した。得られたそれぞれの複合酸化
物のＸ線回折チャートを図５に示す。そして実施例１と
同様に触媒粉末を調製して Total OSCと Partial OSCを
測定し、結果を図２，３に示す。Example 2 The oxide powder prepared in Example 1 was subjected to reduction treatment in a CO stream at 1200 ° C. for 5 hours, then in the atmosphere at 1200 ° C. for 5 hours, and then in a CO stream. 1200 ℃
A plurality of types of complex oxide powders were prepared in the same manner as in Example 1 except that the treatment was carried out for 5 hours at 500 ° C. for 1 hour at 500 ° C. in the atmosphere. The X-ray diffraction chart of each obtained composite oxide is shown in FIG. Then, a catalyst powder was prepared in the same manner as in Example 1 and Total OSC and Partial OSC were measured, and the results are shown in FIGS.
【００４４】（比較例１）実施例１で調製された酸化物
粉末をCO気流中にて1200℃で５時間還元処理し、大気中
にて1200℃で５時間処理したこと以外は実施例１と同様
にして、複数種の複合酸化物粉末を調製した。得られた
それぞれの複合酸化物のＸ線回折チャートを図６に示
す。そして実施例１と同様に触媒粉末を調製して触媒粉
末を調製してTotal OSCと Partial OSCを測定し、結果
を図２，３に示す。Comparative Example 1 Example 1 was repeated except that the oxide powder prepared in Example 1 was subjected to reduction treatment in a CO stream at 1200 ° C. for 5 hours and then in air at 1200 ° C. for 5 hours. In the same manner as above, plural kinds of complex oxide powders were prepared. The X-ray diffraction chart of each obtained composite oxide is shown in FIG. Then, in the same manner as in Example 1, the catalyst powder was prepared, the catalyst powder was prepared, and the Total OSC and Partial OSC were measured. The results are shown in FIGS.
【００４５】＜評価＞図４及び図５より、実施例１，２
の複合酸化物では、蛍石型構造の立方晶に帰属するピー
クとともに、規則相（κ相又はパイロクロア相）に帰属
するピーク（２θ＝37゜など）が観察され、原子比Zr／
Ceが１以上の範囲でも規則相が形成されていることが明
らかである。一方、図６から、比較例１の複合酸化物で
は規則相に帰属するピークが認められず、通常の蛍石構
造となっていることがわかる。<Evaluation> From FIGS. 4 and 5, Examples 1 and 2 are described.
In the complex oxide of, a peak (2θ = 37 °, etc.) attributed to the ordered phase (κ phase or pyrochlore phase) was observed along with the peak attributed to the cubic crystal of the fluorite structure, and the atomic ratio Zr /
It is clear that an ordered phase is formed even when Ce is 1 or more. On the other hand, it can be seen from FIG. 6 that the composite oxide of Comparative Example 1 has no peak attributed to the ordered phase and has a normal fluorite structure.
【００４６】そして図２より、実施例１，２の触媒粉末
はZr／（Ce＋Zr）モル比が 0.5近傍に OSCのピ−クをも
ち、原子比Zr／Ceが１以上の範囲でも比較例１より高い
OSCが発現されていることがわかる。すなわち比較例１
では、大気中1200℃５時間の処理の後に還元処理を行わ
なかったために規則相が生成せず、それによって十分な
OSCが発現しなかったと考えられる。From FIG. 2, the catalyst powders of Examples 1 and 2 had an OSC peak at a Zr / (Ce + Zr) molar ratio of around 0.5, and Comparative Example 1 even when the atomic ratio Zr / Ce was 1 or more. taller than
It can be seen that OSC is expressed. That is, Comparative Example 1
However, since the reduction treatment was not carried out after the treatment at 1200 ° C. for 5 hours in the atmosphere, the ordered phase was not formed, which was sufficient.
It is considered that OSC did not develop.
【００４７】また図３より、Zr／（Ce＋Zr）モル比が
0.6以上の範囲では、実施例１の触媒粉末の OSCが実施
例２より大きくなっている。すなわち1200℃での還元処
理と酸化処理を繰り返すことにより、原子比Zr／Ceが高
い範囲における OSCが向上していることがわかる。これ
は、還元処理と酸化処理を繰り返すことによって、規則
相がさらに形成されたためと考えられる。From FIG. 3, the Zr / (Ce + Zr) molar ratio is
In the range of 0.6 or more, the OSC of the catalyst powder of Example 1 is larger than that of Example 2. That is, it is understood that the OSC in the range where the atomic ratio Zr / Ce is high is improved by repeating the reduction treatment and the oxidation treatment at 1200 ° C. It is considered that this is because the ordered phase was further formed by repeating the reduction treatment and the oxidation treatment.
【００４８】[0048]
【発明の効果】すなわち本発明のセリア−ジルコニア系
複合酸化物によれば、高い耐熱性を有するとともに、原
子比Zr／Ceが１以上である場合でも十分な OSCが発現さ
れる。したがってこれを担体として用いた触媒は、高い
浄化活性が発現される。EFFECTS OF THE INVENTION That is, the ceria-zirconia-based composite oxide of the present invention has high heat resistance and exhibits sufficient OSC even when the atomic ratio Zr / Ce is 1 or more. Therefore, a catalyst using this as a carrier exhibits high purification activity.
【図１】本発明のセリア−ジルコニア系複合酸化物の結
晶構造を示す説明図である。FIG. 1 is an explanatory diagram showing a crystal structure of a ceria-zirconia-based composite oxide of the present invention.
【図２】Zr／（Ce＋Zr）モル比に対する Total OSCを示
すグラフである。FIG. 2 is a graph showing Total OSC with respect to Zr / (Ce + Zr) molar ratio.
【図３】Zr／（Ce＋Zr）モル比に対する Partial OSCを
示すグラフである。FIG. 3 is a graph showing Partial OSC with respect to Zr / (Ce + Zr) molar ratio.
【図４】実施例１の複合酸化物のＸ線回折チャートであ
る。4 is an X-ray diffraction chart of the composite oxide of Example 1. FIG.
【図５】実施例２の複合酸化物のＸ線回折チャートであ
る。5 is an X-ray diffraction chart of the composite oxide of Example 2. FIG.
【図６】比較例１の複合酸化物のＸ線回折チャートであ
る。FIG. 6 is an X-ray diffraction chart of the composite oxide of Comparative Example 1.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 森川 彰 愛知県愛知郡長久手町大字長湫字横道41番 地の１株式会社豊田中央研究所内 (72)発明者 山村 佳恵 愛知県愛知郡長久手町大字長湫字横道41番 地の１株式会社豊田中央研究所内 (72)発明者 曽布川 英夫 愛知県愛知郡長久手町大字長湫字横道41番 地の１株式会社豊田中央研究所内 Ｆターム(参考） 4G048 AA03 AB02 AB06 AC08 AD06 AE05 4G069 AA01 AA03 AA08 BA04A BA04B BB04A BB04B BB06A BB06B BC08A BC29A BC38A BC40A BC40B BC43A BC43B BC51A BC51B BC75B CA03 CA09 DA05 EC27 FA01 FA02 FB09 FB14 FB30 FB44 FC08 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Akira Morikawa Aichi Prefecture Nagachite Town Aichi District Local 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Yoshie Yamamura Aichi Prefecture Nagachite Town Aichi District Local 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Hideo Sofukawa Aichi Prefecture Nagachite Town Aichi District Local 1 Toyota Central Research Institute Co., Ltd. F-term (reference) 4G048 AA03 AB02 AB06 AC08 AD06 AE05 4G069 AA01 AA03 AA08 BA04A BA04B BB04A BB04B BB06A BB06B BC08A BC29A BC38A BC40A BC40B BC43A BC43B BC51A BC51B BC75B CA03 CA09 DA05 EC27 FA01 FA02 FB09 FB14 FB30 FB44 FC08
Claims (4)
土類元素及び遷移元素から選ばれる少なくとも一種の添
加元素の酸化物と、からなり、セリウムイオン及びジル
コニウムイオンが規則配列した規則相をもつことを特徴
とするセリア−ジルコニア系複合酸化物。1. An ordered phase in which CeO 2 and ZrO 2 and an oxide of at least one additive element selected from rare earth elements, alkaline earth elements, and transition elements are regularly arranged with cerium ions and zirconium ions. A ceria-zirconia-based composite oxide characterized by having:
以下の範囲で含まれている請求項１に記載のセリア−ジ
ルコニア系複合酸化物。2. The additive element is 10 mol% in all metal elements.
The ceria-zirconia-based composite oxide according to claim 1, which is included in the following range.
項１に記載のセリア−ジルコニア系複合酸化物。3. The ceria-zirconia-based composite oxide according to claim 1, wherein the additional element is yttrium.
則相を有する請求項１に記載のセリア−ジルコニア系複
合酸化物。4. The ceria-zirconia-based composite oxide according to claim 1, which has the ordered phase even when the atomic ratio Zr / Ce is in the range of 1 or more.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08109021A (en) * | 1994-10-05 | 1996-04-30 | Santoku Kinzoku Kogyo Kk | Composite oxide having oxygen-absorbing and releasing ability and its production |
| JPH09221304A (en) * | 1995-12-07 | 1997-08-26 | Toyota Central Res & Dev Lab Inc | Oxide solid solution particle and its production |
| JPH11165067A (en) * | 1997-12-03 | 1999-06-22 | Kinya Adachi | Production of ceria-zirconia compound oxide for exhaust gas purifying auxiliary catalyst |
| JP2001089143A (en) * | 1999-09-22 | 2001-04-03 | Kinya Adachi | Cerium-containing compound oxide excellent in oxygen absorbing and releasing ability and method of producing the same |
| JP2003073123A (en) * | 2001-08-30 | 2003-03-12 | Toyota Central Res & Dev Lab Inc | Compound oxide and method for producing the same, and auxiliary catalyst for cleaning flue gas |
| JP2003206178A (en) * | 2001-11-12 | 2003-07-22 | Toyota Central Res & Dev Lab Inc | Mixed conductive multiple oxide for oxygen separation and manufacturing method therefor |
-
2002
- 2002-03-22 JP JP2002080890A patent/JP2003277059A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08109021A (en) * | 1994-10-05 | 1996-04-30 | Santoku Kinzoku Kogyo Kk | Composite oxide having oxygen-absorbing and releasing ability and its production |
| JPH09221304A (en) * | 1995-12-07 | 1997-08-26 | Toyota Central Res & Dev Lab Inc | Oxide solid solution particle and its production |
| JPH11165067A (en) * | 1997-12-03 | 1999-06-22 | Kinya Adachi | Production of ceria-zirconia compound oxide for exhaust gas purifying auxiliary catalyst |
| JP2001089143A (en) * | 1999-09-22 | 2001-04-03 | Kinya Adachi | Cerium-containing compound oxide excellent in oxygen absorbing and releasing ability and method of producing the same |
| JP2003073123A (en) * | 2001-08-30 | 2003-03-12 | Toyota Central Res & Dev Lab Inc | Compound oxide and method for producing the same, and auxiliary catalyst for cleaning flue gas |
| JP2003206178A (en) * | 2001-11-12 | 2003-07-22 | Toyota Central Res & Dev Lab Inc | Mixed conductive multiple oxide for oxygen separation and manufacturing method therefor |
Cited By (30)
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| JP2007222868A (en) * | 2006-01-27 | 2007-09-06 | Mitsui Mining & Smelting Co Ltd | Oxygen scavenger and process for producing oxygen scavenger |
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| CN101406829B (en) * | 2006-10-12 | 2012-03-21 | 第一稀元素化学工业株式会社 | Zirconia-ceria-yttria-based mixed oxide and process for producing the same |
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