JP2000140639A - Catalyst for purifying exhaust gas - Google Patents
Catalyst for purifying exhaust gasInfo
- Publication number
- JP2000140639A JP2000140639A JP10316568A JP31656898A JP2000140639A JP 2000140639 A JP2000140639 A JP 2000140639A JP 10316568 A JP10316568 A JP 10316568A JP 31656898 A JP31656898 A JP 31656898A JP 2000140639 A JP2000140639 A JP 2000140639A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- zirconium
- cerium
- exhaust gas
- oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
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- Catalysts (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、排ガス浄化用触媒
に関するもので、自動車などの内燃機関からの排ガス中
に含まれる有害成分である一酸化炭素（ＣＯ）、炭化水
素（ＨＣ）および窒素酸化物（ＮＯX ）を同時に除去す
る排ガス浄化用触媒に係るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying catalyst, and more particularly to carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxides, which are harmful components contained in exhaust gas from internal combustion engines such as automobiles. The present invention relates to an exhaust gas purifying catalyst for simultaneously removing substances (NO x ).
【０００２】[0002]
【従来の技術】従来、排ガス浄化用触媒としては、セラ
ミックスの触媒担体上に耐火性無機酸化物を担持し、該
耐火性無機酸化物に触媒となる貴金属元素および貴金属
元素を安定化して保持する化合物と共に担持して形成さ
れている。特開昭６３−１１１６７４１号公報には、上
記の貴金属元素を安定化して保持する化合物として添加
されたセリウムが、排ガス浄化条件の高温度下における
酸化セリウムの粒成長を抑制し浄化性能を維持するた
め、ジルコニウム酸化物がセリウム酸化物に一部は複合
酸化物ないしは固溶体として存在させた触媒が開示され
ている。2. Description of the Related Art Conventionally, as a catalyst for purifying exhaust gas, a refractory inorganic oxide is supported on a ceramic catalyst carrier, and the refractory inorganic oxide stably holds a noble metal element and a noble metal element serving as a catalyst. It is formed to be supported together with a compound. JP-A-63-1116741 discloses that cerium added as a compound for stabilizing and holding the above-mentioned noble metal element suppresses grain growth of cerium oxide at high temperatures under exhaust gas purification conditions and maintains purification performance. Therefore, a catalyst in which zirconium oxide is partly present in cerium oxide as a composite oxide or a solid solution is disclosed.
【０００３】また、特開平２−４３９５１号公報には、
高温酸化雰囲気のような厳しい条件下でも優れた耐久性
を有し、低温域でも高い浄化性能を有する排ガス浄化用
触媒として、ジルコニア又はジルコニアとイットリアお
よびカルシアよりなる群から選ばれた１種によって安定
化されたセリウム酸化物と、ロジウム、白金およびパラ
ジウムよりなる触媒金属を担持した耐火性無機酸化物の
活性アルミナとをハニカム担体に担持した触媒が開示さ
れている。しかしながら、これらの排ガス浄化用触媒
は、高温域で活性であってもエンジン始動直後の低温雰
囲気では、必ずしも触媒が活性とならなず十分な浄化性
能を示さないという不具合を有する。すなわち、ある程
度以上の温度に触媒が暖まらないと、排ガスの浄化性能
を十分に発揮できない。[0003] Also, Japanese Patent Application Laid-Open No. 2-43951 discloses that
Stable with zirconia or one selected from the group consisting of zirconia, yttria and calcia as an exhaust gas purification catalyst that has excellent durability even under severe conditions such as high temperature oxidizing atmosphere and high purification performance even at low temperatures. There is disclosed a catalyst in which activated cerium oxide and activated alumina of a refractory inorganic oxide supporting a catalyst metal composed of rhodium, platinum and palladium are supported on a honeycomb carrier. However, these exhaust gas purifying catalysts have a drawback that even if they are active in a high temperature range, in a low temperature atmosphere immediately after starting the engine, the catalyst does not always become active and does not show sufficient purification performance. That is, unless the catalyst is heated to a certain temperature or higher, the exhaust gas purification performance cannot be sufficiently exhibited.
【０００４】[0004]
【発明が解決しようとする課題】本発明は、上記の事情
に鑑みてなされたもので低温域での触媒活性および触媒
自体の耐熱性を向上し、エンジン始動後、速やかに触媒
を活性化することを課題とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and improves the catalyst activity in a low temperature range and the heat resistance of the catalyst itself, and activates the catalyst immediately after starting the engine. That is the task.
【０００５】[0005]
【課題を解決するための手段】本発明の排ガス浄化用触
媒は、触媒担体と該触媒担体上に形成された担持層と該
担持層に担持された貴金属触媒とからなる排ガス浄化用
触媒において、該担持層は、ジルコニウム酸化物を担持
した活性アルミナ粉末で形成されており、該貴金属触媒
はロジウムであることを特徴とする。The exhaust gas purifying catalyst of the present invention is an exhaust gas purifying catalyst comprising a catalyst carrier, a carrier layer formed on the catalyst carrier, and a noble metal catalyst carried on the carrier layer. The support layer is formed of activated alumina powder supporting zirconium oxide, and the noble metal catalyst is rhodium.
【０００６】前記担持層を形成する前記活性アルミナ粉
末は、前記ジルコニウム酸化物とともにセリウム酸化物
を担持していることが好ましい。前記活性アルミナ粉末
に担持されている前記ジルコニウムおよび前記セリウム
の総量を１００モル％とすると前記ジルコニウムの担持
量は７５モル％以上であることが好ましい。It is preferable that the activated alumina powder forming the supporting layer supports cerium oxide together with the zirconium oxide. Assuming that the total amount of the zirconium and the cerium supported on the activated alumina powder is 100 mol%, the supported amount of the zirconium is preferably 75 mol% or more.
【０００７】なお、ジルコニウム、セリウムの総量１０
０モル％は、ジルコニウム、セリウム各原子の原子モル
を百分率で表すものである。前記活性アルミナ粉末はラ
ンタンが固溶した安定化アルミナ粉末であることが好ま
しい。前記担持層は予め前記ジルコニウム酸化物が担持
された前記活性アルミナをスラリーから形成されたもの
であることが好ましい。The total amount of zirconium and cerium is 10
0 mol% represents the atomic mol of each atom of zirconium and cerium in percentage. The activated alumina powder is preferably a stabilized alumina powder in which lanthanum is dissolved. It is preferable that the support layer is formed from slurry of the activated alumina on which the zirconium oxide is supported in advance.
【０００８】本発明の排ガス浄化用触媒は、触媒担体と
該触媒担体上に形成された担持層と該担持層に担持され
た貴金属触媒とからなる排ガス浄化用触媒において、該
担持層は、少なくともジルコニウムとセリウムとの混合
酸化物粉末と活性アルミナ粉末とで形成されており、該
貴金属触媒はロジウムであることを特徴とする。[0008] The exhaust gas purifying catalyst of the present invention is an exhaust gas purifying catalyst comprising a catalyst carrier, a carrier layer formed on the catalyst carrier, and a noble metal catalyst carried on the carrier layer. It is formed of a mixed oxide powder of zirconium and cerium and an activated alumina powder, and the noble metal catalyst is rhodium.
【０００９】前記ジルコニウムとセリウムとの混合酸化
物はその総量を１００モル％とするとジルコニウムは７
５モル％以上であることが好ましい。When the total amount of the mixed oxide of zirconium and cerium is 100 mol%, zirconium is 7%.
It is preferably at least 5 mol%.
【００１０】[0010]
【発明の実施の形態】本発明の排ガス浄化用触媒は、触
媒担体と該触媒担体上に形成された無機酸化物の担持層
と該担持層に担持された貴金属触媒とからなる。本発明
の特徴は、貴金属触媒のロジウムがジルコニウム酸化物
を担持した活性アルミナ粉末上に担持された担持層を有
することにある。貴金属触媒のロジウムがジルコニウム
酸化物の近傍に担持されていることでロジウムによる浄
化特性を高めると共にロジウムの安定性や耐久性を保持
することができる。BEST MODE FOR CARRYING OUT THE INVENTION The exhaust gas purifying catalyst of the present invention comprises a catalyst carrier, a support layer of an inorganic oxide formed on the catalyst carrier, and a noble metal catalyst supported on the support layer. A feature of the present invention resides in having a support layer in which rhodium as a noble metal catalyst is supported on activated alumina powder supporting zirconium oxide. Since the noble metal catalyst rhodium is supported in the vicinity of the zirconium oxide, the purification characteristics of rhodium can be enhanced, and the stability and durability of rhodium can be maintained.
【００１１】ロジウムを活性アルミナ、あるいはセリウ
ム酸化物を含む活性アルミナに担持した場合よりもロジ
ウムの優れた浄化触媒としての効果が発揮できる。さら
に、前記ジルコニウムを担持した活性アルミナに対して
劣位量セリウム酸化物を配合した担持層成分にロジウム
を担持した担持層も同様にロジウムによる浄化特性を高
めると共にロジウムの安定性や耐久性を保持することが
できる。[0011] Rhodium can be more effectively used as a purifying catalyst than rhodium supported on activated alumina or activated alumina containing cerium oxide. Further, the supporting layer in which rhodium is supported in a supporting layer component in which cerium oxide is blended with the inferior amount cerium oxide with respect to the activated alumina supporting zirconium also similarly enhances the purification characteristics of rhodium and maintains the stability and durability of rhodium. be able to.
【００１２】前記活性アルミナ粉末に担持されているジ
ルコニウム酸化物およびセリウム酸化物の量は、ジルコ
ニウムおよびセリウムの総量を１００モル％とすると、
該ジルコニウムの担持量は７５モル％以上とすることが
好ましい。セリウムの添加量が２５モル％以上となると
触媒の低温活性が失われるので好ましくない。前記活性
アルミナ粉末は、ランタンを固溶すること活性アルミナ
が安定化され担持している酸化物および貴金属触媒が安
定化されて触媒の浄化性能が向上するので好ましい。The amounts of zirconium oxide and cerium oxide supported on the activated alumina powder are as follows, assuming that the total amount of zirconium and cerium is 100 mol%.
The zirconium loading is preferably at least 75 mol%. If the amount of cerium added is 25 mol% or more, the low-temperature activity of the catalyst is lost, which is not preferable. The activated alumina powder is preferable because it dissolves lanthanum, because the activated alumina is stabilized and the oxide and the noble metal catalyst carried are stabilized, and the purification performance of the catalyst is improved.
【００１３】触媒担体上に形成される上記の担持層は、
ジルコニウム酸化物、必要に応じてセリウム酸化物を混
合して担持した活性アルミナ粉末にロジウムを担持した
混合物をスラリー状にして触媒担体上にコートして担持
することで均一な担持層が形成できる。この活性アルミ
ナ粉末などの酸化物をスラリーで担持する際、貴金属触
媒のロジウムを予め前記酸化物粉末に担持したスラリー
を用いて担持層を形成することが好ましい。これによ
り、触媒金属のロジウムがジルコニウム酸化物上に均一
に分散し、安定化し触媒の耐熱性を高め触媒活性を有効
に発揮させることができる。The above-mentioned supporting layer formed on the catalyst carrier comprises:
A uniform support layer can be formed by forming a slurry in which a mixture of rhodium is supported on activated alumina powder in which zirconium oxide and, if necessary, cerium oxide are mixed and supported is coated on a catalyst carrier and supported. When the oxide such as the activated alumina powder is supported by the slurry, it is preferable to form a support layer using a slurry in which rhodium as a noble metal catalyst is previously supported on the oxide powder. As a result, the catalyst metal rhodium is uniformly dispersed on the zirconium oxide, and the catalyst metal can be stabilized, the heat resistance of the catalyst can be increased, and the catalyst activity can be effectively exhibited.
【００１４】前記触媒担体上には、さらに貴金属触媒の
白金やパラジウムなどを担持した活性アルミナ粉末およ
びセリウム酸化物、ジルコニウム酸化物とからなる担持
成分を上記のロジウムを担持した担持成分に混合して均
一のスラリーとして触媒担体上に担持して触媒を形成す
ることができる。前記触媒担体は、例えばセラミックス
や金属製のハニカム構造体のモノリス担体が利用でき
る。On the catalyst carrier, a support component comprising activated alumina powder carrying noble metal catalysts such as platinum and palladium and a support component comprising cerium oxide and zirconium oxide are mixed with the above-mentioned support component carrying rhodium. The catalyst can be formed on a catalyst carrier as a uniform slurry. As the catalyst support, for example, a monolithic support having a honeycomb structure made of ceramics or metal can be used.
【００１５】本発明の第２の排ガス浄化用触媒は、ロジ
ウムを担持した担持層がジルコニウムとセリウムとの混
合酸化物と活性アルミナとの混合物に担持して形成され
ている。ロジウムを担持した担持層をジルコニウムに富
むセリウムとの混合酸化物で構成することによりロジウ
ムの安定性を保ち浄化用触媒のクロス浄化率をより高め
ることができる。In the second exhaust gas purifying catalyst of the present invention, a support layer supporting rhodium is formed by supporting a mixed oxide of zirconium and cerium and a mixture of activated alumina. By forming the support layer supporting rhodium with a mixed oxide with zirconium-rich cerium, the stability of rhodium can be maintained and the cross-purification rate of the purification catalyst can be further increased.
【００１６】この混合酸化物は、例えばセリウム、ジル
コニウムのそれぞれの溶解液を混合してアンモニア水で
共沈殿させて生成物を焼成して形成することができる。
この際ジルコニウムの量は、混合酸化物中に７５モル％
以上存在することが触媒の安定性を高め触媒活性を保持
するために好ましい。また、この際ロジウムはジルコニ
ウムとセリウムの混合酸化物に直接担持した後、活性ア
ルミナを混合してスラリー状として担持層を形成しても
よい。なお、使用する活性アルミナ粉末はランタンを固
溶しなくても安定な担持層の形成が可能となる。This mixed oxide can be formed, for example, by mixing the respective solutions of cerium and zirconium, co-precipitating them with aqueous ammonia, and calcining the product.
At this time, the amount of zirconium was 75 mol% in the mixed oxide.
The presence of the above is preferable in order to enhance the stability of the catalyst and maintain the catalytic activity. At this time, rhodium may be directly supported on a mixed oxide of zirconium and cerium, and then mixed with activated alumina to form a slurry to form a support layer. In addition, the active alumina powder used can form a stable carrier layer without dissolving lanthanum as a solid solution.
【００１７】本発明の第２の排ガス浄化用触媒も同様
に、貴金属触媒のロジウムに加えて白金を担持した担持
層を加えて担持してもよい。白金の担持もロジウムと同
様にセリウムとジルコニウムの酸化物に担持して用いる
ことが好ましい。そして、トータルとしてのセリウムと
ジルコニウムの比率においてもジルコニウムのモル比率
が高いもの、すなわちジルコニウムのモル％が７５以上
であることが好ましい。Similarly, the second exhaust gas purifying catalyst of the present invention may be supported by adding a support layer supporting platinum in addition to the noble metal catalyst rhodium. It is preferable that platinum is supported on an oxide of cerium and zirconium, similarly to rhodium. It is also preferable that the molar ratio of zirconium is high, that is, the molar percentage of zirconium is 75 or more in the total ratio of cerium and zirconium.
【００１８】担持層に担持する酸化物の総量は、触媒容
量１リットル当たり、セリウム、ジルコニウム量がそれ
ぞれ０．１〜０．４モル／Ｌ、０．１〜０．６モル／Ｌ
の範囲であることが望ましい。触媒中でのセリウム量が
０．１モル／Ｌ未満の場合、酸素吸蔵量が減少し、触媒
活性が低下する。また、０．４モル／Ｌを超えると性能
の向上は僅かでコスト面で好ましくない。ジルコニウム
量が０．１モル／Ｌ未満の場合、ロジウムの安定性が低
下すので好ましくない。また、０．６モル／Ｌを超えて
添加しても触媒の安定性の向上は僅かであり高価となる
ので好ましくない。The total amount of oxides carried on the carrier layer is 0.1 to 0.4 mol / L and 0.1 to 0.6 mol / L for cerium and zirconium, respectively, per liter of catalyst volume.
Is desirably within the range. When the amount of cerium in the catalyst is less than 0.1 mol / L, the oxygen storage amount decreases, and the catalytic activity decreases. On the other hand, if it exceeds 0.4 mol / L, the performance is slightly improved, which is not preferable in terms of cost. When the amount of zirconium is less than 0.1 mol / L, the stability of rhodium is undesirably reduced. Addition of more than 0.6 mol / L is not preferable because the stability of the catalyst is slightly improved and becomes expensive.
【００１９】また、ロジウムの担持量は、触媒容量１リ
ットル当たり０．０１〜５ｇであることが望ましい。ロ
ジウムの担持量が０．０１ｇ／Ｌ未満の場合、十分な触
媒活性が得られないので好ましくない。また５ｇ／Ｌを
超えると、それ以上ロジウムの担持量を増加させても性
能向上は僅かで高価となり好ましくない。白金を担持す
る場合の担持量は、０．１〜５ｇである。担持量が０．
１ｇ／Ｌ未満の場合、十分な触媒活性が得られないおそ
れがあり好ましくない。また、５ｇ／Ｌを超えると、そ
れ以上白金の担持量を増加させても性能の向上は僅かで
高価となるので好ましくない。The amount of rhodium supported is desirably 0.01 to 5 g per liter of catalyst. If the supported amount of rhodium is less than 0.01 g / L, it is not preferable because sufficient catalytic activity cannot be obtained. If the amount exceeds 5 g / L, even if the amount of rhodium supported is further increased, the performance is slightly increased and the cost is not preferable. When platinum is loaded, the loading amount is 0.1 to 5 g. The loading amount is 0.
If it is less than 1 g / L, sufficient catalytic activity may not be obtained, which is not preferable. On the other hand, if it exceeds 5 g / L, even if the amount of supported platinum is further increased, the performance is slightly improved and the cost becomes high, which is not preferable.
【００２０】このような貴触媒金属のロジウムをジルコ
ニウム酸化物が富む担持層に担持した構成とすること
で、同じ組成で均一に担持した触媒に比較して、低温域
での触媒活性度を高くすることができる。すなわち、本
発明の触媒では耐久試験後の触媒の５０％浄化温度を低
くでき低温活性の課題が実現できる。By employing such a structure in which rhodium as a noble catalyst metal is supported on a zirconium oxide-rich support layer, the catalyst activity in a low temperature region is higher than that of a catalyst uniformly supported with the same composition. can do. That is, in the catalyst of the present invention, the 50% purification temperature of the catalyst after the durability test can be lowered, and the problem of low-temperature activity can be realized.
【００２１】[0021]
【実施例】以下、実施例により具体的に説明する。 （実施例１）３モル％のランタンを含有する活性アルミ
ナ粉末を、硝酸ジルコニウム水溶液中に浸漬し、攪拌
後、乾燥、焼成してジルコニウムを担持したランタン含
有活性アルミナ粉末を得た。The present invention will be specifically described below with reference to examples. Example 1 An activated alumina powder containing 3 mol% of lanthanum was immersed in an aqueous solution of zirconium nitrate, stirred, dried and fired to obtain a lanthanum-containing activated alumina powder carrying zirconium.
【００２２】このジルコニウム酸化物担持活性アルミナ
粉末を硝酸ロジウム水溶液中に浸漬し、乾燥しロジウム
を固定した粉末を得た。このロジウムを固定した活性ア
ルミナ粉末と硝酸水溶液、バインダーおよび脱イオン水
とでスラリー化しスラリーＡを得た。次に、３モル％の
ランタンを含有活性アルミナ粉末を、硝酸セリウム溶液
と硝酸ジルコニウム溶液を混合した溶液中（セリウムと
ジルコニウムの比でセリウム量が多い溶液）に浸漬し、
攪拌後、該溶液中にアンモニア水を添加し、乾燥、焼成
してランタン含有活性アルミナに、セリウム酸化物とジ
ルコニウム酸化物を担持した粉末を得た。The activated alumina powder supporting zirconium oxide was immersed in an aqueous solution of rhodium nitrate and dried to obtain a powder having rhodium fixed thereon. A slurry A was obtained by slurrying the activated alumina powder having the rhodium fixed thereon, an aqueous nitric acid solution, a binder and deionized water. Next, the activated alumina powder containing 3 mol% of lanthanum is immersed in a solution obtained by mixing a cerium nitrate solution and a zirconium nitrate solution (a solution containing a large amount of cerium in a ratio of cerium to zirconium),
After stirring, aqueous ammonia was added to the solution, dried and calcined to obtain a powder in which cerium oxide and zirconium oxide were supported on lanthanum-containing activated alumina.
【００２３】更に、この粉末をジニトロジアミン白金溶
液中に浸漬し、乾燥し白金を固定したセリウム酸化物と
ジルコニウム酸化物担持活性アルミナ粉末を得た。この
白金を固定したセリウム酸化物とジルコニウム酸化物を
担持した活性アルミナ粉末と硝酸水溶液、バインダーお
よび脱イオン水でスラリー化しスラリーＢを得た。スラ
リーＡおよびスラリーＢを１：１の割合で混合し、直径
８０ｍｍ、長さ１００ｍｍのハニカム担体にコート、乾
燥、焼成して触媒１を得た。Further, this powder was immersed in a dinitrodiamine platinum solution and dried to obtain activated alumina powder carrying cerium oxide and zirconium oxide with platinum fixed thereon. A slurry B was obtained by slurrying the activated alumina powder carrying cerium oxide and zirconium oxide on which platinum was fixed, an aqueous nitric acid solution, a binder and deionized water. The slurry A and the slurry B were mixed at a ratio of 1: 1 and coated on a honeycomb carrier having a diameter of 80 mm and a length of 100 mm, dried and fired to obtain a catalyst 1.
【００２４】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．２１ｍｏｌ／Ｌ、Ｚｒ０．２９ｍｏ
ｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （実施例２）３モル％のランタンを含有活性アルミナ粉
末を、硝酸セリウム溶液と硝酸ジルコニウム溶液を混合
した溶液中（セリウムとジルコニウムの比でジルコニウ
ム量が多い溶液）に浸漬し、攪拌後、該溶液中にアンモ
ニア水を添加し、乾燥、焼成してランタン含有活性アル
ミナにセリウム酸化物とジルコニウム酸化物とを担持し
た粉末を得た。The catalyst composition was Pt 1.5 g / L, Rh0.
3g / L, Ce 0.21mol / L, Zr 0.29mo
1 / L and La 0.03 mol / L. (Example 2) An activated alumina powder containing 3 mol% of lanthanum was immersed in a mixed solution of a cerium nitrate solution and a zirconium nitrate solution (a solution having a large amount of zirconium in a ratio of cerium to zirconium), and the mixture was stirred. Aqueous ammonia was added to the solution, dried and calcined to obtain a powder in which cerium oxide and zirconium oxide were supported on lanthanum-containing activated alumina.
【００２５】上記酸化物担持活性アルミナ粉末を硝酸ロ
ジウム水溶液中に浸漬し、乾燥しロジウムを固定した粉
末を得た。このロジウムを固定した酸化物担持活性アル
ミナ粉末と硝酸水溶液、バインダーおよび脱イオン水と
でスラリー化しスラリーＡを得た。次に、３モル％のラ
ンタンを含有活性アルミナ粉末を、硝酸セリウム溶液と
硝酸ジルコニウム溶液を混合した溶液中（セリウムとジ
ルコニウムの比でジルコニウム量が多い溶液）に浸漬
し、攪拌後、該溶液中にアンモニア水を添加し、乾燥、
焼成してランタン含有活性アルミナにセリウム酸化物と
ジルコニウム酸化物を担持した粉末を得た。The oxide-supported activated alumina powder was immersed in an aqueous solution of rhodium nitrate and dried to obtain a powder having rhodium fixed thereon. This rhodium-fixed oxide-supported activated alumina powder was slurried with a nitric acid aqueous solution, a binder and deionized water to obtain a slurry A. Next, the activated alumina powder containing 3 mol% of lanthanum is immersed in a solution obtained by mixing a cerium nitrate solution and a zirconium nitrate solution (a solution having a large amount of zirconium in a ratio of cerium to zirconium), and after stirring, the solution Add ammonia water to
Calcination was performed to obtain a powder in which cerium oxide and zirconium oxide were supported on activated alumina containing lanthanum.
【００２６】更に、上記の酸化物担持粉末をジニトロジ
アミン白金溶液中に浸漬し、乾燥し白金を固定した活性
アルミナ粉末を得た。この白金を固定した上記酸化物を
担持した活性アルミナ粉末と硝酸水溶液、バインダーお
よび脱イオン水でスラリー化しスラリーＢを得た。スラ
リーＡおよびスラリーＢを１：１の割合で混合し、直径
８０ｍｍ、長さ１００ｍｍのハニカム担体にコート、乾
燥、焼成して触媒２を得た。Further, the above-mentioned oxide-carrying powder was immersed in a dinitrodiamine platinum solution and dried to obtain platinum-fixed activated alumina powder. A slurry B was obtained by slurrying the activated alumina powder carrying the above-mentioned platinum-fixed oxide, an aqueous nitric acid solution, a binder and deionized water. The slurry A and the slurry B were mixed at a ratio of 1: 1 and coated on a honeycomb carrier having a diameter of 80 mm and a length of 100 mm, dried and fired to obtain a catalyst 2.
【００２７】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．１４ｍｏｌ／Ｌ、Ｚｒ０．３６ｍｏ
ｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （実施例３）活性アルミナ粉末にセリウム酸化物とジル
コニウム酸化物の担持比率を変えた以外実施例２と同様
の操作により触媒３を得た。The catalyst composition was Pt 1.5 g / L, Rh0.
3g / L, Ce 0.14mol / L, Zr0.36mo
1 / L and La 0.03 mol / L. (Example 3) Catalyst 3 was obtained in the same manner as in Example 2, except that the loading ratio of cerium oxide and zirconium oxide was changed in the activated alumina powder.
【００２８】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．１６ｍｏｌ／Ｌ、Ｚｒ０．３４ｍｏ
ｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （実施例４）硝酸セリウム溶液と硝酸ジルコニウム溶液
を混合した溶液中（セリウムとジルコニウムの比でジル
コニウム量が多い溶液）にアンモニア水を添加して生成
した、セリウム・ジルコニウムの共沈殿物を、乾燥、焼
成してセリウム、ジルコニウム混合酸化物を得た。The catalyst composition was Pt 1.5 g / L, Rh0.
3g / L, Ce 0.16mol / L, Zr0.34mo
1 / L and La 0.03 mol / L. (Example 4) A co-precipitate of cerium-zirconium formed by adding aqueous ammonia to a mixed solution of a cerium nitrate solution and a zirconium nitrate solution (a solution having a large amount of zirconium in a ratio of cerium to zirconium) was dried. Then, firing was performed to obtain a mixed oxide of cerium and zirconium.
【００２９】このセリウム、ジルコニウムの混合酸化物
と、活性アルミナ粉末を硝酸ロジウム溶液中に浸漬し、
乾燥してロジウムを固定した混合酸化物を含む活性アル
ミナ粉末を得た。このロジウムを固定した上記で得た粉
末と硝酸水溶液および脱イオン水でスラリー化しスラリ
ーＡを得た。The mixed oxide of cerium and zirconium and the activated alumina powder are immersed in a rhodium nitrate solution,
It was dried to obtain an activated alumina powder containing a mixed oxide in which rhodium was fixed. The rhodium-fixed powder obtained above was slurried with a nitric acid aqueous solution and deionized water to obtain a slurry A.
【００３０】硝酸セリウム溶液と硝酸ジルコニウム溶液
を混合した溶液中（セリウムとジルコニウムの比でセリ
ウム量が多い溶液）にアンモニア水を添加して生成し
た、セリウム・ジルコニウムの共沈殿物を、乾燥、焼成
してセリウム、ジルコニウム混合酸化物を得た。このセ
リウム、ジルコニウムの混合酸化物と、活性アルミナ粉
末をジニトロジアミン白金溶液中に浸漬し、乾燥して白
金を固定した混合酸化物含有活性アルミナ粉末を得た。A co-precipitate of cerium-zirconium formed by adding aqueous ammonia to a mixed solution of a cerium nitrate solution and a zirconium nitrate solution (a solution containing a large amount of cerium in a ratio of cerium to zirconium) is dried and fired. Thus, a mixed oxide of cerium and zirconium was obtained. The mixed oxide of cerium and zirconium and the activated alumina powder were immersed in a dinitrodiamine platinum solution and dried to obtain a mixed oxide-containing active alumina powder having platinum fixed thereon.
【００３１】このロジウムを固定した上記の粉末と硝酸
水溶液および脱イオン水でスラリー化しスラリーＢを得
た。スラリーＡおよびスラリーＢを１：１の割合で混合
し、直径８０ｍｍ、長さ１００ｍｍのハニカム担体にコ
ート、乾燥、焼成して触媒４を得た。触媒組成は、Ｐｔ
１．５ｇ／Ｌ、Ｒｈ０．３ｇ／Ｌ、Ｃｅ０．１６ｍｏｌ
／Ｌ、Ｚｒ０．３４ｍｏｌ／Ｌ、Ｌａ０．０３ｍｏｌ／
Ｌであった。 （実施例５）硝酸セリウム溶液と硝酸ジルコニウム溶液
を混合した溶液中（セリウムとジルコニウムの比でジル
コニウム量が多い溶液）にアンモニア水を添加して生成
した、セリウム・ジルコニウムの共沈殿物を、乾燥、焼
成してセリウム、ジルコニウム混合酸化物を得た。The above rhodium-fixed powder was slurried with an aqueous nitric acid solution and deionized water to obtain a slurry B. The slurry A and the slurry B were mixed at a ratio of 1: 1 and coated on a honeycomb carrier having a diameter of 80 mm and a length of 100 mm, dried and fired to obtain a catalyst 4. The catalyst composition is Pt
1.5 g / L, Rh 0.3 g / L, Ce 0.16 mol
/ L, Zr0.34mol / L, La0.03mol /
L. (Example 5) A cerium-zirconium coprecipitate formed by adding aqueous ammonia to a mixed solution of a cerium nitrate solution and a zirconium nitrate solution (a solution having a large amount of zirconium in a ratio of cerium to zirconium) was dried. Then, firing was performed to obtain a mixed oxide of cerium and zirconium.
【００３２】このセリウム、ジルコニウムの酸化物を硝
酸ロジウム溶液中に浸漬し、乾燥してロジウムを固定し
た混合酸化物粉末を得た。このロジウムを固定したセリ
ウム、ジルコニウムの混合酸化物粉末と活性アルミナ
と、硝酸水溶液および脱イオン水でスラリー化しスラリ
ーＡを得た。硝酸セリウム溶液と硝酸ジルコニウム溶液
を混合した溶液中（セリウムとジルコニウムの比でセリ
ウム量が多い溶液）にアンモニア水を添加して生成し
た、セリウム・ジルコニウムの共沈殿物を、乾燥、焼成
してセリウム、ジルコニウム混合酸化物を得た。The cerium and zirconium oxides were immersed in a rhodium nitrate solution and dried to obtain a mixed oxide powder having rhodium fixed thereon. A slurry A was obtained by slurrying the mixed oxide powder of cerium and zirconium to which rhodium was fixed, activated alumina, a nitric acid aqueous solution and deionized water. A cerium-zirconium co-precipitate formed by adding aqueous ammonia to a mixed solution of a cerium nitrate solution and a zirconium nitrate solution (a solution containing a large amount of cerium in the ratio of cerium to zirconium) is dried and fired to obtain cerium nitrate. Thus, a zirconium mixed oxide was obtained.
【００３３】このセリウム、ジルコニウムの混合酸化物
粉末をジニトロジアミン白金溶液中に浸漬し、乾燥して
白金を固定した粉末を得た。このロジウムを固定したセ
リウム、ジルコニウム混合酸化物粉末と、活性アルミナ
粉末と硝酸水溶液および脱イオン水でスラリー化しスラ
リーＢを得た。スラリーＡおよびスラリーＢを１：１の
割合で混合し、直径８０ｍｍ、長さ１００ｍｍのハニカ
ム担体にコート、乾燥、焼成して触媒５を得た。The mixed oxide powder of cerium and zirconium was immersed in a dinitrodiamine platinum solution and dried to obtain a powder having platinum fixed thereon. A slurry B was obtained by slurrying the cerium and zirconium mixed oxide powder to which the rhodium was fixed, the activated alumina powder, an aqueous nitric acid solution and deionized water. The slurry A and the slurry B were mixed at a ratio of 1: 1 and coated on a honeycomb carrier having a diameter of 80 mm and a length of 100 mm, dried and fired to obtain a catalyst 5.
【００３４】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．１６ｍｏｌ／Ｌ、Ｚｒ０．３４ｍｏ
ｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （比較例１）３モル％のランタンを含有する活性アルミ
ナを、硝酸ロジウム水溶液中に浸漬し、乾燥してロジウ
ムを固定した粉末を得た。The catalyst composition was Pt 1.5 g / L, Rh0.
3g / L, Ce 0.16mol / L, Zr0.34mo
1 / L and La 0.03 mol / L. Comparative Example 1 Activated alumina containing 3 mol% of lanthanum was immersed in an aqueous solution of rhodium nitrate and dried to obtain a powder in which rhodium was fixed.
【００３５】このロジウムを固定した粉末と硝酸水溶液
および脱イオン水でスリラー化しスラリーＡを得た。次
に３モル％のランタンを含有する活性アルミナをジニト
ロジアミン白金溶液中に浸漬し、乾燥して白金を固定し
た粉末を得た。この白金を固定した粉末と硝酸水溶液お
よび脱イオン水でスリラー化しスラリーＢを得た。This rhodium-fixed powder was chilled with a nitric acid aqueous solution and deionized water to obtain a slurry A. Next, activated alumina containing 3 mol% of lanthanum was immersed in a dinitrodiamine platinum solution and dried to obtain a powder having platinum fixed thereon. A slurry B was obtained by chilling with the platinum-fixed powder, an aqueous nitric acid solution and deionized water.
【００３６】スラリーＡおよびスラリーＢを１：１の割
合で混合し、直径８０ｍｍ、長さ１００ｍｍのハニカム
担体にコート、乾燥、焼成して触媒２を得た。触媒組成
は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．３ｇ／Ｌ、Ｌａ０．０
３ｍｏｌ／Ｌであった。 （比較例２）活性アルミナ粉末を硝酸セリウム溶液中に
浸漬し、乾燥、焼成してセリウム含有アルミナ粉末を得
た。セリウム担持活性アルミナ粉末を硝酸ロジウム溶液
中に浸漬し、乾燥してロジウムを固定した粉末を得た。
このロジウムを固定した粉末と硝酸水溶液および脱イオ
ン水でスラリー化しスラリーＡを得た。The slurry A and the slurry B were mixed at a ratio of 1: 1 and coated on a honeycomb carrier having a diameter of 80 mm and a length of 100 mm, dried and fired to obtain a catalyst 2. The catalyst composition was Pt 1.5 g / L, Rh 0.3 g / L, La 0.0
It was 3 mol / L. Comparative Example 2 Activated alumina powder was immersed in a cerium nitrate solution, dried and fired to obtain a cerium-containing alumina powder. The cerium-supported activated alumina powder was immersed in a rhodium nitrate solution and dried to obtain a powder in which rhodium was fixed.
This rhodium-fixed powder was slurried with an aqueous nitric acid solution and deionized water to obtain a slurry A.
【００３７】活性アルミナ粉末を硝酸セリウム溶液中に
浸漬し、乾燥、焼成してセリウム含有アルミナ粉末を得
た。セリウム担持活性アルミナ粉末をジニトロジアミン
白金溶液中に浸漬し、乾燥して白金を固定した粉末を得
た。この白金を固定した粉末と硝酸水溶液および脱イオ
ン水でスラリー化しスラリーＢを得た。スラリーＡおよ
びスラリーＢを１：１の割合で混合し、直径８０ｍｍ、
長さ１００ｍｍのハニカム担体にコート、乾燥、焼成し
て触媒２を得た。The activated alumina powder was immersed in a cerium nitrate solution, dried and fired to obtain a cerium-containing alumina powder. The cerium-supported activated alumina powder was immersed in a dinitrodiamine platinum solution and dried to obtain a powder having platinum fixed thereon. A slurry was obtained by slurrying the platinum-fixed powder with an aqueous nitric acid solution and deionized water. The slurry A and the slurry B were mixed at a ratio of 1: 1 and the diameter was 80 mm,
A 100 mm long honeycomb carrier was coated, dried, and fired to obtain Catalyst 2.
【００３８】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （比較例３）ロジウムの担持部のセリウムとジルコニウ
ムの比率を表１に示したように３０：７０変え、白金担
持部をジルコニウムのみとした以外は実施例２と同様の
方法で触媒を調製した。The catalyst composition was Pt 1.5 g / L, Rh0.
It was 3 g / L and La 0.03 mol / L. Comparative Example 3 A catalyst was prepared in the same manner as in Example 2 except that the ratio of cerium and zirconium in the rhodium-supporting portion was changed to 30:70 as shown in Table 1, and the platinum-supporting portion was changed to only zirconium. .
【００３９】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．７５ｍｏｌ／Ｌ、Ｚｒ０．４２５ｍ
ｏｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （比較例４）ロジウム担持部および白金担持部のセリウ
ムとジルコニウムの比率を表１に示したように変えた以
外は実施例２と同様の方法で触媒を調製した。The catalyst composition was Pt 1.5 g / L, Rh0.
3 g / L, Ce 0.75 mol / L, Zr 0.425 m
ol / L and La 0.03 mol / L. Comparative Example 4 A catalyst was prepared in the same manner as in Example 2 except that the ratio of cerium and zirconium in the rhodium-supporting portion and the platinum-supporting portion was changed as shown in Table 1.
【００４０】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．３ｍｏｌ／Ｌ、Ｚｒ０．２ｍｏｌ／
Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （比較例５）ロジウム担持部および白金担持部のセリウ
ムとジルコニウムの比率を表１に示したように変えた以
外は実施例２と同様の方法で触媒を調製した。The catalyst composition was Pt 1.5 g / L, Rh0.
3 g / L, Ce 0.3 mol / L, Zr 0.2 mol /
L and La were 0.03 mol / L. Comparative Example 5 A catalyst was prepared in the same manner as in Example 2 except that the ratio of cerium and zirconium in the rhodium-supporting portion and the platinum-supporting portion was changed as shown in Table 1.
【００４１】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．１６ｍｏｌ／Ｌ、Ｚｒ０．３４ｍｏ
ｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。 （比較例６）３モル％のランタンを含有活性アルミナ
を、硝酸セリウム溶液と硝酸ジルコニウム溶液を混合し
た溶液中（セリウムとジルコニウムの比でジルコニウム
量が多い溶液）に浸漬し、攪拌後、該溶液中にアンモニ
ア水を添加し、乾燥、焼成してランタン含有活性アルミ
ナと、セリウム、ジルコニウム酸化物含有粉末を得た。
この混合粉末に硝酸水溶液、バインダーおよび脱イオン
水でスラリー化しスラリーＡを得た。The catalyst composition was Pt 1.5 g / L, Rh0.
3g / L, Ce 0.16mol / L, Zr0.34mo
1 / L and La 0.03 mol / L. (Comparative Example 6) Activated alumina containing 3 mol% of lanthanum was immersed in a solution obtained by mixing a cerium nitrate solution and a zirconium nitrate solution (a solution having a large amount of zirconium in a ratio of cerium to zirconium), and the solution was stirred. Aqueous ammonia was added, dried and calcined to obtain lanthanum-containing activated alumina and cerium and zirconium oxide-containing powder.
The mixed powder was slurried with an aqueous nitric acid solution, a binder and deionized water to obtain a slurry A.
【００４２】このスラリーＡを直径８０ｍｍ、長さ１０
０ｍｍのハニカム担体にコート、乾燥後、硝酸セリウム
溶液および硝酸ジルコニウム溶液に浸漬後、乾燥、焼成
してコート層を形成した。次に上記のコート層をジニト
ロジアミン白金溶液、および硝酸ロジウム溶液に浸漬し
触媒を調製した。This slurry A was prepared with a diameter of 80 mm and a length of 10 mm.
A 0 mm honeycomb carrier was coated, dried, immersed in a cerium nitrate solution and a zirconium nitrate solution, dried and fired to form a coat layer. Next, the above-mentioned coat layer was immersed in a dinitrodiamine platinum solution and a rhodium nitrate solution to prepare a catalyst.
【００４３】触媒組成は、Ｐｔ１．５ｇ／Ｌ、Ｒｈ０．
３ｇ／Ｌ、Ｃｅ０．１２５ｍｏｌ／Ｌ、Ｚｒ０．３７５
ｍｏｌ／Ｌ、Ｌａ０．０３ｍｏｌ／Ｌであった。上記の
各触媒の構成と組成およびトータルのＣｅおよびＺｒの
担持量を表１に示した。The catalyst composition was Pt 1.5 g / L, Rh0.
3 g / L, Ce 0.125 mol / L, Zr 0.375
mol / L and La 0.03 mol / L. Table 1 shows the structure and composition of each of the above catalysts and the total amount of Ce and Zr carried.
【００４４】[0044]
【表１】 [Table 1]
【００４５】（試験例）実施例１〜５および比較例１〜
６で得られた触媒を２個ずつ別々に排気量４０００ＣＣ
のガソリンエンジンに取り付け、第１図に示すエージン
グ条件で、平均のエンジン回転数３５００ｒｐｍ、触媒
入り口排気ガス温度８００℃、触媒中央部の排気ガス温
度１０５０℃で２０時間の耐久試験を行った。(Test Example) Examples 1 to 5 and Comparative Examples 1 to
The catalysts obtained in Step 6 were each separated into two units.
And a 20 hour endurance test at an average engine speed of 3500 rpm, an exhaust gas temperature at the catalyst inlet of 800 ° C., and an exhaust gas temperature of 1050 ° C. at the center of the catalyst under the aging conditions shown in FIG.
【００４６】エージング条件は第１図に示すように、１
サイクルを３０秒とするサイクルで、１サイクル中の初
めの１０秒は理論空燃費Ａ／Ｆ＝１４．６で制御し、そ
の後、燃料を２６秒目まで増大させ１０秒目から１６秒
目までＡ／Ｆ＝１３前後の状態を保つ。また、１６秒目
から３０秒目まで２次空気を導入することにより、１６
秒目から２５秒目までＡ／Ｆ＝１４．８に制御し、その
まま３０秒目まで続ける制御をするものである。１サイ
クルの１６秒目から触媒中央部の温度が上昇し、１０５
０℃に達し、２６秒目からは酸素過剰下で１０５０℃か
ら温度が降下する耐久試験となる。The aging condition is, as shown in FIG.
In the cycle in which the cycle is 30 seconds, the first 10 seconds in one cycle are controlled by the stoichiometric air-fuel consumption A / F = 14.6, and then the fuel is increased to 26 seconds and from 10 seconds to 16 seconds. A / F = about 13 is maintained. Also, by introducing the secondary air from the 16th to the 30th second, the 16
A / F = 14.8 is controlled from the second to the 25th second, and control is continued until the 30th second. From the 16th second of one cycle, the temperature at the center of the catalyst increased to 105
The temperature reaches 0 ° C., and from the 26th second, an endurance test is conducted in which the temperature drops from 1050 ° C. under an excess of oxygen.
【００４７】前記した耐久試験を行った各触媒は、次に
排気量２０００ＣＣのガソリンエンジンに取り付け、触
媒性能を評価した。評価条件はエンジン回転数を１４０
０ｒｐｍ、理論空燃費Ａ／Ｆ＝１４．６で制御し、触媒
入口の温度を変化させてＨＣ、ＣＯおよびＮＯXの５０
％浄化温度を求めた。また、ＨＣ−ＮＯXとＣＯ−ＮＯ X
のクロス浄化率と、その評価結果を表２に示す。なお、
表１中の貴金属触媒の量は全て同じ量であり担持部の組
成および担持状態の差異によることを示している。Each of the catalysts subjected to the durability test described above has the following
Attached to a 2000CC gasoline engine and touched
The medium performance was evaluated. The evaluation condition is that the engine speed is 140
Control at 0 rpm, theoretical air-fuel efficiency A / F = 14.6, catalyst
HC, CO and NO by changing the inlet temperatureXOf 50
% Purification temperature was determined. Also, HC-NOXAnd CO-NO X
Table 2 shows the cross-purification rates and the evaluation results. In addition,
The amounts of the noble metal catalysts in Table 1 are all the same, and
This is due to the difference between the composition and the supported state.
【００４８】[0048]
【表２】 [Table 2]
【００４９】表２に示すように本実施例１から５の各触
媒は、比較例１から６の各触媒と比較してＨＣ、ＣＯ、
ＮＯXの各５０％浄化温度が耐久試験後においても低く
なっている。すなわち、低温域においても活性を示し触
媒が耐熱性を保持していることが判る。さらにクロス浄
化率の値も高くなっている。比較例６はアルミナにセリ
ウムとジルコニウムを同時に担持したコート層を形成し
た後に、触媒金属を担持した触媒で、５０％浄化温度が
高く、クロス浄化率が最も低い。比較例１はアルミナの
単独のコート層の場合でクロス浄化率および５０％浄化
温度は比較例６よりは向上するが５０％浄化温度は、各
実施例に比べても低い。比較例２は、ジルコニウムを全
く含まない場合でクロス浄化率および５０％浄化温度も
充分でない。比較例３は、セリウムがロジウム担持部で
多く、白金担持部では存在しない例で比較例２と同様に
充分な浄化性能を示さない。比較例４は、ロジウム、白
金担持部共セリウム量が多い場合でこの場合も実施例に
比べて充分な浄化性能を示していない。比較例５は、ロ
ジウム担持部のセリウム量が多い場合でありトータルと
して同じセリウムとジルコニウム量の実施例３に比べて
浄化性能が充分でない。As shown in Table 2, the catalysts of Examples 1 to 5 were different from the catalysts of Comparative Examples 1 to 6 in that HC, CO,
Each 50% purification temperature of the NO X is low even after the durability test. That is, it is understood that the catalyst shows activity even in a low temperature range and the catalyst maintains heat resistance. Furthermore, the value of the cross purification rate is also high. Comparative Example 6 is a catalyst in which a coat layer in which cerium and zirconium are simultaneously supported on alumina is formed, and then a catalyst metal is supported. The catalyst has a high 50% purification temperature and the lowest cross purification rate. Comparative Example 1 is a case of a single coat layer of alumina, in which the cross purification rate and the 50% purification temperature are improved as compared with Comparative Example 6, but the 50% purification temperature is lower than each of the examples. Comparative Example 2 does not contain any zirconium, and the cloth purification rate and the 50% purification temperature are not sufficient. Comparative Example 3 is an example in which cerium is abundant in the rhodium-carrying portion and not present in the platinum-carrying portion, and does not exhibit sufficient purification performance as in Comparative Example 2. Comparative Example 4 has a high rhodium / platinum-carrying cerium content, and in this case also does not show sufficient purification performance as compared with the example. Comparative Example 5 is a case where the amount of cerium in the rhodium-supporting portion is large, and the purification performance is not sufficient as compared with Example 3 having the same amount of cerium and zirconium as a whole.
【００５０】実施例１〜３は請求項１に相当する触媒組
成であり、実施例４と５が請求項６に相当する触媒組成
を用いている。上記のように本発明の触媒はいずれも優
れた排ガス浄化性能を有していることを示している。ま
た、実施例３と比較例１についての耐久試験後の触媒の
５０％浄化温度およびクロス浄化率を図２、３に示し
た。Examples 1 to 3 use a catalyst composition corresponding to claim 1, and Examples 4 and 5 use a catalyst composition corresponding to claim 6. As described above, all of the catalysts of the present invention have excellent exhaust gas purification performance. FIGS. 2 and 3 show the 50% purification temperature and the cross purification rate of the catalyst after the durability test for Example 3 and Comparative Example 1. FIG.
【００５１】表２および図２、３に示したように、本発
明の触媒は耐久試験後においても浄化性能が優れ低温域
でも高い排ガス浄化性能を有することを示している。As shown in Table 2 and FIGS. 2 and 3, it is shown that the catalyst of the present invention has excellent purification performance even after the durability test and has high exhaust gas purification performance even in a low temperature range.
【００５２】[0052]
【発明の効果】本発明の排ガス浄化用触媒は、触媒金属
であるロジウムがジルコニウム酸化物リッチの担持層上
に担持されているため、ロジウムの安定性が高まり従来
の触媒に比べて耐熱性が向上する。耐久試験後において
も高い浄化性能を有し、かつ比較的低温域で浄化性能を
発揮することができる。したがって、エンジン始動後に
おいても速やかに触媒活性を示して、排ガスを浄化する
ことができる。According to the exhaust gas purifying catalyst of the present invention, rhodium, which is a catalytic metal, is supported on a zirconium oxide-rich support layer, so that the stability of rhodium is improved and the heat resistance is higher than that of a conventional catalyst. improves. It has high purification performance even after the durability test, and can exhibit purification performance in a relatively low temperature range. Therefore, even after the engine is started, the catalyst activity is promptly exhibited and the exhaust gas can be purified.
【図１】試験例における触媒のエージング条件の説明図
である。FIG. 1 is an explanatory diagram of aging conditions of a catalyst in a test example.
【図２】試験例における実施例１と比較例１の触媒のＨ
Ｃ、ＣＯ、ＮＯ Xの５０％浄化温度の棒グラフである。FIG. 2 shows H of the catalysts of Example 1 and Comparative Example 1 in a test example.
C, CO, NO X5 is a bar graph of the 50% purification temperature.
【図３】試験例における実施例１と比較例１の触媒のク
ロス浄化率の棒グラフである。FIG. 3 is a bar graph showing the cross-purification rates of the catalysts of Example 1 and Comparative Example 1 in a test example.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 佐藤 容規 静岡県小笠郡大東町千浜7800番地 キャタ ラー工業株式会社内 Ｆターム(参考） 3G091 AA02 AA17 AA28 AB03 BA03 BA07 BA14 BA15 BA19 BA39 CA22 DC01 EA30 FA02 FA04 FA12 FA13 FA14 FA18 FB02 FB03 FB11 FB12 FC01 FC07 FC08 GA06 GB01W GB01X GB05W GB06W GB07W GB10X GB16X HB07 4D048 AA06 AA13 AA18 AB03 BA03X BA03Y BA08X BA08Y BA18X BA18Y BA19X BA19Y BA30Y BA33X BA33Y BB02 EA04 4G069 AA03 BA01A BA01B BA05A BA05B BA27B BB12B BC42A BC42B BC43A BC43B BC71A BC71B BC75B BE14B CA03 CA09 DA05 EA18 ED06 FA02 FB13 FB30 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yuki Sato 7800 Chihama, Oto-cho, Ogasa-gun, Shizuoka Prefecture F-term (reference) 3G091 AA02 AA17 AA28 AB03 BA03 BA07 BA14 BA15 BA19 BA39 CA22 DC01 EA30 FA02 FA04 FA12 FA13 FA14 FA18 FB02 FB03 FB11 FB12 FC01 FC07 FC08 GA06 GB01W GB01X GB05W GB06W GB07W GB10X GB16X HB07 4D048 AA06 AA13 AA18 AB03 BA03X BA03Y BA08X BA08Y BA18X BA18Y BA19BBABABABBABBABBABBAYBA18A BC43A BC43B BC71A BC71B BC75B BE14B CA03 CA09 DA05 EA18 ED06 FA02 FB13 FB30
Claims (7)
持層と該担持層に担持された貴金属触媒とからなる排ガ
ス浄化用触媒において、 該担持層は、ジルコニウム酸化物を担持した活性アルミ
ナ粉末で形成されており、該貴金属触媒はロジウムであ
ることを特徴とする排ガス浄化用触媒。1. An exhaust gas purifying catalyst comprising a catalyst carrier, a carrier layer formed on the catalyst carrier, and a noble metal catalyst carried on the carrier layer, wherein the carrier layer comprises activated alumina carrying zirconium oxide. An exhaust gas purifying catalyst formed of powder, wherein the noble metal catalyst is rhodium.
粉末は、前記ジルコニウム酸化物とともにセリウム酸化
物を担持している請求項１記載の排ガス浄化用触媒。2. The exhaust gas purifying catalyst according to claim 1, wherein the activated alumina powder forming the support layer supports cerium oxide together with the zirconium oxide.
前記ジルコニウムおよび前記セリウムの総量を１００モ
ル％とすると、前記ジルコニウムの担持量は７５モル％
以上である請求項２記載の排ガス浄化用触媒。3. When the total amount of zirconium and cerium supported on the activated alumina powder is 100 mol%, the supported amount of zirconium is 75 mol%.
The exhaust gas purifying catalyst according to claim 2, which is as described above.
した安定化アルミナ粉末である請求項１記載の排ガス浄
化用触媒。4. The exhaust gas purifying catalyst according to claim 1, wherein the activated alumina powder is a stabilized alumina powder in which lanthanum is dissolved.
物が担持された前記活性アルミナをスラリーから形成さ
れたものである請求項１記載の排ガス浄化用触媒。5. The exhaust gas purifying catalyst according to claim 1, wherein the support layer is formed from a slurry of the activated alumina on which the zirconium oxide is supported in advance.
持層と該担持層に担持された貴金属触媒とからなる排ガ
ス浄化用触媒において、 該担持層は、少なくともジルコニウムとセリウムとの混
合酸化物粉末と活性アルミナ粉末とで形成されており、
該貴金属触媒はロジウムであることを特徴とする排ガス
浄化用触媒。6. An exhaust gas purifying catalyst comprising a catalyst carrier, a carrier layer formed on the catalyst carrier, and a noble metal catalyst carried on the carrier layer, wherein the carrier layer comprises at least mixed oxidation of zirconium and cerium. Powder and activated alumina powder,
An exhaust gas purifying catalyst, wherein the noble metal catalyst is rhodium.
化物はその総量を１００モル％とするとジルコニウムは
７５モル％以上である請求項６記載の排ガス浄化用触
媒。7. The exhaust gas purifying catalyst according to claim 6, wherein the total amount of the mixed oxide of zirconium and cerium is 100 mol%, and zirconium is at least 75 mol%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31656898A JP4382180B2 (en) | 1998-11-06 | 1998-11-06 | Exhaust gas purification catalyst |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31656898A JP4382180B2 (en) | 1998-11-06 | 1998-11-06 | Exhaust gas purification catalyst |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2009178786A Division JP4674264B2 (en) | 2009-07-31 | 2009-07-31 | Exhaust gas purification catalyst |
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| Publication Number | Publication Date |
|---|---|
| JP2000140639A true JP2000140639A (en) | 2000-05-23 |
| JP4382180B2 JP4382180B2 (en) | 2009-12-09 |
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|---|---|---|---|
| JP31656898A Expired - Fee Related JP4382180B2 (en) | 1998-11-06 | 1998-11-06 | Exhaust gas purification catalyst |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6620762B2 (en) * | 2000-07-18 | 2003-09-16 | Daihatsu Motor Co., Ltd. | Exhaust gas purifying catalyst |
| JP2004114015A (en) * | 2002-09-30 | 2004-04-15 | Toyota Motor Corp | Exhaust gas cleaning catalyst and method of evaluating its cleaning capacity |
| EP1520616A1 (en) * | 2003-09-30 | 2005-04-06 | Tokyo Roki Co., Ltd. | Exhaust gas purifying catalyst |
| JP2007301530A (en) * | 2006-05-15 | 2007-11-22 | Mazda Motor Corp | Exhaust gas purification catalyst |
| JP2010075788A (en) * | 2008-09-24 | 2010-04-08 | Mitsubishi Motors Corp | Exhaust cleaning catalyst for use in internal combustion engine |
| JP2012096158A (en) * | 2010-11-01 | 2012-05-24 | Mazda Motor Corp | Exhaust gas purification catalyst |
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| WO1990014888A1 (en) * | 1989-06-09 | 1990-12-13 | N.E. Chemcat Corporation | Exhaust gas purifying catalyst excellent in thermal resistance and method of production thereof |
| JPH03131343A (en) * | 1989-10-18 | 1991-06-04 | Nissan Motor Co Ltd | Preparation of catalyst for purifying exhaust gas |
| JPH08229394A (en) * | 1994-12-28 | 1996-09-10 | Toyota Central Res & Dev Lab Inc | Production of oxide-deposited catalyst carrier |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS63156545A (en) * | 1986-12-18 | 1988-06-29 | Nippon Shokubai Kagaku Kogyo Co Ltd | Catalyst for purifying exhaust gas |
| WO1990014888A1 (en) * | 1989-06-09 | 1990-12-13 | N.E. Chemcat Corporation | Exhaust gas purifying catalyst excellent in thermal resistance and method of production thereof |
| JPH03131343A (en) * | 1989-10-18 | 1991-06-04 | Nissan Motor Co Ltd | Preparation of catalyst for purifying exhaust gas |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6620762B2 (en) * | 2000-07-18 | 2003-09-16 | Daihatsu Motor Co., Ltd. | Exhaust gas purifying catalyst |
| JP2004114015A (en) * | 2002-09-30 | 2004-04-15 | Toyota Motor Corp | Exhaust gas cleaning catalyst and method of evaluating its cleaning capacity |
| EP1520616A1 (en) * | 2003-09-30 | 2005-04-06 | Tokyo Roki Co., Ltd. | Exhaust gas purifying catalyst |
| JP2005103410A (en) * | 2003-09-30 | 2005-04-21 | Tokyo Roki Co Ltd | Exhaust gas cleaning catalyst |
| US7235511B2 (en) | 2003-09-30 | 2007-06-26 | Tokyo Roki Co., Ltd. | Exhaust gas purifying catalyst |
| JP2007301530A (en) * | 2006-05-15 | 2007-11-22 | Mazda Motor Corp | Exhaust gas purification catalyst |
| JP2010075788A (en) * | 2008-09-24 | 2010-04-08 | Mitsubishi Motors Corp | Exhaust cleaning catalyst for use in internal combustion engine |
| JP2012096158A (en) * | 2010-11-01 | 2012-05-24 | Mazda Motor Corp | Exhaust gas purification catalyst |
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|---|---|
| JP4382180B2 (en) | 2009-12-09 |
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