JP2003170047A - Catalyst for cleaning exhaust gas and method for manufacturing the same - Google Patents
Catalyst for cleaning exhaust gas and method for manufacturing the sameInfo
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- JP2003170047A JP2003170047A JP2002276848A JP2002276848A JP2003170047A JP 2003170047 A JP2003170047 A JP 2003170047A JP 2002276848 A JP2002276848 A JP 2002276848A JP 2002276848 A JP2002276848 A JP 2002276848A JP 2003170047 A JP2003170047 A JP 2003170047A
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- catalyst
- supported
- exhaust gas
- composite oxide
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- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、排気ガス浄化用触
媒及びその製造方法に関する。TECHNICAL FIELD The present invention relates to an exhaust gas purifying catalyst and a method for producing the same.
【０００２】[0002]
【従来の技術】火花点火式エンジンの排気ガスを浄化す
る触媒として三元触媒が知られている。これは、一般に
は活性金属としてのＰｔ及びＲｈと、この活性金属を安
定化させガスとの接触面積を拡大して浄化性能を向上さ
せるサポート材としてのアルミナと、酸素吸蔵物質（Ｏ
ＳＣ）としてのセリア（助触媒）とによって構成するこ
とが多い。A three-way catalyst is known as a catalyst for purifying exhaust gas of a spark ignition type engine. This is generally because Pt and Rh as active metals, alumina as a support material that stabilizes the active metals and expands the contact area with gas to improve the purification performance, and oxygen storage material (O
It is often composed of ceria (co-catalyst) as SC).
【０００３】一方、特許文献１には、Ｎｄ−Ｚｒ複合酸
化物にＲｈを担持させてなる成分と、アルミナやセリア
にＰｔを担持させてなる成分とを混合して担体にコーテ
ィングし、しかる後にそのコーティング層にＢａ溶液を
含浸させることにより、ＢａＯを担体１Ｌ当たり２０ｇ
担持させることが記載されている。また、そのことによ
って、Ｒｈの耐熱性が向上することが記載されている。On the other hand, in Patent Document 1, a component prepared by supporting Rh on an Nd-Zr composite oxide and a component prepared by supporting Pt on alumina or ceria are mixed and coated on a carrier. By impregnating the coating layer with a Ba solution, 20 g of BaO was added per 1 L of the carrier.
Loading is described. Moreover, it is described that the heat resistance of Rh improves by that.
【０００４】[0004]
【特許文献１】特開平０９−１４１０９８号公報（段落
００２０，００５４，００６０）[Patent Document 1] Japanese Patent Laid-Open No. 09-141098 (paragraphs 0020, 0054, 0060)
【０００５】[0005]
【発明が解決しようとする課題】しかし、セリアは一般
に耐熱性が低いという問題がある。このため、エンジン
の高負荷運転によって触媒が高温に晒されると、酸素吸
蔵能が低下して、触媒性能、特にＨＣ（炭化水素）浄化
に関する低温活性が大きく低下する結果となる。また、
Ｒｈは、少量でＨＣ、ＣＯ、ＮＯｘ（窒素酸化物）３成
分の浄化に活性を示し、特にＮＯｘの浄化性能が優れて
おり、このＲｈをセリアに担持させると、その酸化劣化
が防止され、つまりその活性の維持に有利になる。しか
し、上述の如く、セリアの耐熱性が低いことから、触媒
が高温に晒された後は、Ｒｈが不安定になり、シンタリ
ング等を生じて排気ガスの浄化に有効に利用されなくな
る、という問題がある。However, ceria generally has a problem of low heat resistance. For this reason, when the catalyst is exposed to a high temperature due to the high load operation of the engine, the oxygen storage capacity is lowered, and the catalyst performance, particularly the low temperature activity related to purification of HC (hydrocarbon), is largely reduced. Also,
Rh is active in purifying HC, CO, and NOx (nitrogen oxide) three components in a small amount, and particularly has excellent NOx purifying performance. When Rh is supported on ceria, its oxidative deterioration is prevented, That is, it is advantageous to maintain the activity. However, as described above, since ceria has low heat resistance, after the catalyst is exposed to high temperature, Rh becomes unstable, and sintering or the like occurs, so that it cannot be effectively used for purification of exhaust gas. There's a problem.
【０００６】また、エンジンオイルにＰ（リン）が含ま
れている場合、このＰがガラス状の化合物を生成して触
媒表面を覆い、触媒内部へのガスの拡散を阻害して、そ
の浄化性能を低下させる、という問題がある。また、こ
のＰは、アルミナやセリアと化合物を形成してそれらを
劣化させる、さらには活性成分であるＰｔ等と化合して
これを劣化させる、という問題がある。When the engine oil contains P (phosphorus), this P forms a glassy compound to cover the surface of the catalyst, hinders the diffusion of gas into the inside of the catalyst, and purifies it. There is a problem that it lowers. Further, there is a problem in that P forms a compound with alumina or ceria to deteriorate them, and further, it combines with Pt or the like which is an active component to deteriorate this.
【０００７】本発明は、以上のようなセリアの耐熱性の
問題、Ｒｈのシンタリングの問題、Ｐ被毒の問題を解決
せんとするものである。The present invention is intended to solve the above problems of heat resistance of ceria, sintering of Rh, and P poisoning.
【０００８】[0008]
【課題を解決するための手段】本発明は、このような課
題を解決するために、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物とＢａ
とを利用したものである。In order to solve such a problem, the present invention provides a Ce-Zr-Nd composite oxide and Ba.
And are used.
【０００９】まず、請求項１に係る発明は、Ｒｈ及びＢ
ａを含有する排気ガス浄化用触媒において、さらに、Ｃ
ｅ・Ｚｒ・Ｎｄ複合酸化物を含有し、上記Ｃｅ・Ｚｒ・Ｎｄ
複合酸化物に上記Ｒｈ及びＢａが担持されていることを
特徴とする。First, the invention according to claim 1 relates to Rh and B.
In the exhaust gas purifying catalyst containing a, C
The above Ce · Zr · Nd containing the e · Zr · Nd composite oxide
The composite oxide is characterized in that the above Rh and Ba are supported.
【００１０】すなわち、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物（複
酸化物又は混合酸化物）は、セリアと同様に酸素吸蔵物
質として働くが、セリアに比して耐熱性が高く、触媒が
高温に晒された後でも、結晶がそれほど粗大化しない。
このため、高い酸素吸蔵能が維持される。つまり、三元
触媒におけるＨＣ、ＣＯ及びＮＯｘを高効率で浄化可能
な空燃比のウィンドウが狭くならず、高い浄化性能が維
持される。同時に、このＣｅ・Ｚｒ・Ｎｄ複合酸化物に担
持されているＲｈの活性も維持され、ＨＣ、ＣＯ及びＮ
Ｏｘの浄化に有利になる。That is, although Ce / Zr / Nd complex oxide (complex oxide or mixed oxide) acts as an oxygen storage substance like ceria, it has higher heat resistance than ceria and the catalyst is exposed to high temperatures. Even after being treated, the crystals do not coarsen so much.
Therefore, a high oxygen storage capacity is maintained. That is, the window of the air-fuel ratio capable of highly efficiently purifying HC, CO, and NOx in the three-way catalyst is not narrowed, and high purification performance is maintained. At the same time, the activity of Rh supported on this Ce / Zr / Nd complex oxide is also maintained, and HC, CO and N are retained.
It is advantageous for purification of Ox.
【００１１】また、本発明に係る触媒では、上記Ｃｅ・
Ｚｒ・Ｎｄ複合酸化物にＲｈと共にＢａが担持されてい
るから、このＢａによってＲｈのシンタリングが抑制さ
れる。しかも、このＢａは排気ガス中のＰと化合物を形
成して触媒のＰ被毒による性能低下を抑制する。すなわ
ち、ＢａはＰと共にリン酸バリウムを生成するが、この
化合物はガスの拡散を妨げないから、触媒性能を低下さ
せない。そうして、ＢａがＰと化合することにより、触
媒のＰ被毒量が相対的に少なくなり、触媒の活性の維持
に有利になる。Further, in the catalyst according to the present invention, the above Ce.
Since Ba is supported on the Zr.Nd composite oxide together with Rh, the Ba suppresses sintering of Rh. Moreover, this Ba forms a compound with P in the exhaust gas and suppresses performance deterioration due to P poisoning of the catalyst. That is, Ba produces barium phosphate together with P, but since this compound does not hinder the diffusion of gas, it does not deteriorate the catalytic performance. Then, by combining Ba with P, the amount of P poisoning of the catalyst becomes relatively small, which is advantageous for maintaining the activity of the catalyst.
【００１２】請求項２に係る発明は、請求項１に記載さ
れている排気ガス浄化用触媒において、上記Ｒｈ、Ｂａ
及びＣｅ・Ｚｒ・Ｎｄ複合酸化物は担体に担持されてい
て、該担体１Ｌ当たりのＢａ担持量が５〜３０ｇである
ことを特徴とする。The invention according to claim 2 provides the exhaust gas purifying catalyst according to claim 1, wherein the Rh and Ba are
And Ce / Zr / Nd composite oxide are supported on a carrier, and the amount of supported Ba per 1 L of the carrier is 5 to 30 g.
【００１３】すなわち、Ｂａは少量でも上記Ｒｈのシン
タリング抑制及びＰ被毒抑制に有効であるものの、その
量が少なくなり過ぎると、その効果はそれだけ低くな
る。一方、Ｂａ担持量が多くなり過ぎると、Ｒｈなど触
媒の貴金属成分を覆ってその活性を低下させる。また、
セラミック製担体にあっては、Ｂａが該担体を攻撃して
これを脆くし、担体から触媒コーティング層が剥落し易
くなる。このため、Ｂａ担持量は、５〜３０ｇ／Ｌ程度
とすることが好ましいものであり、さらに好ましいのは
１０〜２２ｇ／Ｌ或いは１０〜１５ｇ／Ｌである。That is, even if a small amount of Ba is effective in suppressing the sintering of Rh and suppressing P poisoning, if the amount is too small, the effect becomes so low. On the other hand, if the amount of carried Ba is too large, it covers the noble metal component of the catalyst such as Rh and reduces its activity. Also,
In the case of a ceramic carrier, Ba attacks the carrier to make it brittle, and the catalyst coating layer easily peels off from the carrier. Therefore, the amount of Ba supported is preferably about 5 to 30 g / L, and more preferably 10 to 22 g / L or 10 to 15 g / L.
【００１４】請求項３に係る発明は、請求項１又は請求
項２に記載されている排気ガス浄化用触媒において、さ
らに、Ｐｔ及びアルミナを含有し、上記Ｒｈ及びＰｔ
は、前者が上記Ｃｅ・Ｚｒ・Ｎｄ複合酸化物に、後者が上
記アルミナに互いに分かれて担持され、上記Ｒｈを担持
したＣｅ・Ｚｒ・Ｎｄ複合酸化物と、上記Ｐｔを担持した
アルミナとが混合した状態で含まれていることを特徴と
する。According to a third aspect of the present invention, in the exhaust gas purifying catalyst according to the first or second aspect, Pt and alumina are further contained, and the above Rh and Pt are contained.
The former is the Ce.Zr.Nd composite oxide, the latter is separately supported on the alumina, and the Ce.Zr.Nd composite oxide carrying the Rh is mixed with the alumina carrying the Pt. It is characterized in that it is included in the state.
【００１５】すなわち、このようにＲｈとＰｔとをＣｅ
・Ｚｒ・Ｎｄ複合酸化物とアルミナとに分けて担持するこ
とにより、この両者のシンタリングが防止され、Ｃｅ・
Ｚｒ・Ｎｄ複合酸化物及びＢａによる触媒の耐熱性の向
上、並びにＰ被毒抑制に有利になる。また、Ｒｈを担持
したＣｅ・Ｚｒ・Ｎｄ複合酸化物と、Ｐｔを担持したアル
ミナとが混合した状態になっているから、ＨＣ、ＣＯ及
びＮＯｘを効率良く浄化する上で有利になる。That is, as described above, Rh and Pt are Ce
By separately supporting Zr.Nd composite oxide and alumina, sintering of both is prevented, and Ce.
It is advantageous for improving the heat resistance of the catalyst by the Zr.Nd complex oxide and Ba and for suppressing P poisoning. Further, since the Ce-Zr-Nd composite oxide supporting Rh and the alumina supporting Pt are in a mixed state, it is advantageous in efficiently purifying HC, CO and NOx.
【００１６】請求項４に係る発明は、担体に複数の触媒
層が層状に形成されていて、上記複数の触媒層のうち内
側に位置する触媒層は、アルミナにＰｄが担持されてな
る成分と、酸素吸蔵物質とを含有し、上記内側触媒層よ
りも外側に位置する触媒層は、Ｃｅ・Ｚｒ・Ｎｄ複合酸化
物にＲｈ及びＢａが担持されてなる成分を含有すること
を特徴とする排気ガス浄化用触媒である。According to a fourth aspect of the present invention, a plurality of catalyst layers are formed in layers on a carrier, and the inner catalyst layer among the plurality of catalyst layers is a component in which Pd is supported on alumina. And an oxygen storage substance, and the catalyst layer located outside the inner catalyst layer contains a component in which Rh and Ba are supported on a Ce-Zr-Nd composite oxide. It is a gas purification catalyst.
【００１７】すなわち、Ｐｄは、低温でのＨＣ浄化に有
利であるが、熱劣化し易く、しかも鉛、硫黄等による被
毒を生じ易いことが知られている。これに対して、本発
明では、このＰｄを酸素吸蔵物質と共に内側触媒層に配
置し、これを外側触媒層で覆ったから、この外側触媒層
の障壁効果によってＰｄの熱劣化、被毒を避けながら、
触媒の低温活性の向上を図ることができる。そうして、
熱及び被毒の面で内側触媒層よりも厳しい環境になる外
側触媒層に、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物にＲｈ及びＢａ
が担持されてなる成分を配置したから、上述（請求項
１）の如く、触媒が高温に晒されても酸素吸蔵能の低下
やＲｈのシンタリングは抑えられ、また、Ｐ被毒も抑え
られ、長期間にわたって触媒性能を維持する上で有利に
なる。That is, although Pd is advantageous for HC purification at low temperatures, it is known that Pd is easily deteriorated by heat and that it is easily poisoned by lead, sulfur and the like. On the other hand, in the present invention, this Pd is arranged in the inner catalyst layer together with the oxygen storage substance, and is covered with the outer catalyst layer. Therefore, the barrier effect of the outer catalyst layer avoids thermal deterioration and poisoning of Pd. ,
The low temperature activity of the catalyst can be improved. And then
Ce / Zr / Nd composite oxide is used as Rh and Ba for the outer catalyst layer, which has a more severe environment than the inner catalyst layer in terms of heat and poisoning.
As described above (Claim 1), even if the catalyst is exposed to high temperature, the decrease in oxygen storage capacity and sintering of Rh can be suppressed, and P poisoning can be suppressed. It is advantageous in maintaining the catalyst performance for a long period of time.
【００１８】請求項５に係る発明は、Ｒｈ、Ｂａ及びＣ
ｅ・Ｚｒ・Ｎｄ複合酸化物を含有する排気ガス浄化用触媒
の製造方法であって、上記Ｃｅ・Ｚｒ・Ｎｄ複合酸化物に
上記Ｒｈを担持させて焼成し、上記Ｒｈを担持したＣｅ
・Ｚｒ・Ｎｄ複合酸化物に上記Ｂａを担持させることを特
徴とする。The invention according to claim 5 is Rh, Ba and C.
A method for producing an exhaust gas purifying catalyst containing an e.Zr.Nd composite oxide, comprising: Ce containing the Rh supported on the Ce.Zr.Nd composite oxide and calcined.
-The above-mentioned Ba is supported on the Zr-Nd composite oxide.
【００１９】従って、これにより、Ｃｅ・Ｚｒ・Ｎｄ複合
酸化物にＲｈ及びＢａが担持されてなる触媒が得られ、
触媒が高温に晒されても酸素吸蔵能の低下やＲｈのシン
タリングが少なくなるとともに、Ｐ被毒も抑えられ、長
期間にわたって触媒性能を維持する上で有利になる。Accordingly, a catalyst comprising Rh and Ba supported on the Ce-Zr-Nd composite oxide can be obtained.
Even when the catalyst is exposed to high temperature, the oxygen storage capacity is reduced and the Rh sintering is reduced, and P poisoning is suppressed, which is advantageous in maintaining the catalyst performance for a long period of time.
【００２０】[0020]
【発明の効果】以上のように、請求項１に係る発明によ
れば、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物にＲｈ及びＢａが担持
されているから、触媒が高温に晒されても酸素吸蔵能の
低下やＲｈのシンタリングが少なくなるとともに、Ｐ被
毒も抑えられ、触媒の耐熱性ないしは耐久性の向上に有
利になる。As described above, according to the invention of claim 1, since Rh and Ba are supported on the Ce-Zr-Nd composite oxide, the oxygen storage capacity is high even when the catalyst is exposed to high temperature. Of P and poisoning of Rh are reduced, and P poisoning is also suppressed, which is advantageous for improving the heat resistance or durability of the catalyst.
【００２１】請求項２に係る発明によれば、請求項１に
記載されている排気ガス浄化用触媒において、担体１Ｌ
当たりのＢａ担持量が５〜３０ｇであるから、Ｒｈの活
性を妨げることなく、また、担体の劣化を招くことな
く、Ｒｈのシンタリングを抑制し、また、触媒のＰ被毒
を抑制することができる。According to the invention of claim 2, in the exhaust gas purifying catalyst of claim 1, the carrier 1L is used.
Since the amount of supported Ba is 5 to 30 g per unit, it is possible to suppress the sintering of Rh and prevent P poisoning of the catalyst without hindering the activity of Rh and causing deterioration of the carrier. You can
【００２２】請求項３に係る発明によれば、請求項１又
は請求項２に記載されている排気ガス浄化用触媒におい
て、さらに、Ｒｈ及びＰｔをＣｅ・Ｚｒ・Ｎｄ複合酸化物
とアルミナに分けて担持し、このＲｈを担持したＣｅ・
Ｚｒ・Ｎｄ複合酸化物と、Ｐｔを担持したアルミナとを
混合した状態にしたから、Ｒｈ及びＰｔのシンタリング
を防止しながら、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物及びＢａに
よって触媒の耐熱性ないし耐久性を向上させることがで
き、また、ＨＣ、ＣＯ及びＮＯｘを浄化にも有利にな
る。According to the invention of claim 3, in the exhaust gas purifying catalyst of claim 1 or 2, Rh and Pt are further divided into Ce / Zr / Nd composite oxide and alumina. Ce, which carries this Rh
Since the Zr / Nd composite oxide and Pt-supported alumina were mixed, the heat resistance or durability of the catalyst was improved by the Ce / Zr / Nd composite oxide and Ba while preventing the sintering of Rh and Pt. The property can be improved, and it is also advantageous for purification of HC, CO and NOx.
【００２３】請求項４に係る発明によれば、内側触媒層
は、アルミナにＰｄを担持してなる成分と、酸素吸蔵物
質とを含有し、外側触媒層は、Ｃｅ・Ｚｒ・Ｎｄ複合酸化
物にＲｈ及びＢａが担持されてなる成分を含有するか
ら、Ｐｄの熱劣化、被毒を避けながら、触媒の低温活性
の向上を図ることができるとともに、触媒が高温に晒さ
れても酸素吸蔵能の低下やＲｈのシンタリングは抑えら
れ、また、Ｐ被毒も抑えられることになり、長期間にわ
たって触媒性能を維持する上で有利になる。According to the invention of claim 4, the inner catalyst layer contains a component in which Pd is supported on alumina and an oxygen storage material, and the outer catalyst layer is a Ce / Zr / Nd composite oxide. Since Rh and Ba contain a component loaded with Rh and Ba, it is possible to improve the low temperature activity of the catalyst while avoiding the thermal deterioration and poisoning of Pd, and also to improve the oxygen storage capacity even when the catalyst is exposed to high temperatures. Of Rh and sintering of Rh are suppressed, and P poisoning is also suppressed, which is advantageous in maintaining catalyst performance for a long period of time.
【００２４】請求項５に係る発明によれば、Ｃｅ・Ｚｒ・
Ｎｄ複合酸化物にＲｈを担持させて焼成し、しかる後
に、このＲｈを担持したＣｅ・Ｚｒ・Ｎｄ複合酸化物にＢ
ａを担持させるようにしたから、触媒が高温に晒されて
も酸素吸蔵能の低下やＲｈのシンタリングが少なく、ま
た、Ｐ被毒も抑えられた耐久性の高い触媒が得られる。According to the invention of claim 5, Ce.Zr.
The Nd composite oxide was loaded with Rh and fired, and then the Rh-supported Ce / Zr / Nd composite oxide was added with B.
Since a is supported, even if the catalyst is exposed to a high temperature, there is little reduction in oxygen storage capacity and sintering of Rh, and a highly durable catalyst in which P poisoning is suppressed can be obtained.
【００２５】[0025]
【発明の実施の形態】以下、本発明の実施の形態を図面
に基づいて説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
【００２６】図１において、１は自動車の火花点火式エ
ンジンであり、２はその気筒、４はその燃焼室、５は点
火プラグ、６は吸気通路、７は排気通路である。この排
気通路７に三元触媒８が配置されている。In FIG. 1, 1 is a spark ignition engine of an automobile, 2 is its cylinder, 4 is its combustion chamber, 5 is a spark plug, 6 is an intake passage, and 7 is an exhaust passage. A three-way catalyst 8 is arranged in this exhaust passage 7.
【００２７】＜三元触媒の構成＞三元触媒８は、図２に
示すように、担体１１の表面に内側触媒層１２と外側触
媒層１３とが層状に形成されてなる。<Structure of Three-Way Catalyst> As shown in FIG. 2, the three-way catalyst 8 is formed by layering an inner catalyst layer 12 and an outer catalyst layer 13 on the surface of a carrier 11.
【００２８】担体１１は、コージェライト製のハニカム
担体である。内側触媒層１２は、Ｐｄをアルミナに担持
させてなるＰｄ／アルミナ成分と、酸化セリウム（セリ
ア）と、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物と、バインダとを含
有する。外側触媒層１３は、Ｐｔをアルミナに担持させ
てなるＰｔ／アルミナ成分と、ＲｈをＣｅ・Ｚｒ・Ｎｄ複
合酸化物に担持させてなるＲｈ／Ｃｅ・Ｚｒ・Ｎｄ成分
と、バインダとを含有する。The carrier 11 is a cordierite honeycomb carrier. The inner catalyst layer 12 contains a Pd / alumina component in which Pd is supported on alumina, cerium oxide (ceria), a Ce.Zr.Nd composite oxide, and a binder. The outer catalyst layer 13 contains a Pt / alumina component in which Pt is supported on alumina, a Rh / Ce.Zr.Nd component in which Rh is supported on a Ce.Zr.Nd complex oxide, and a binder. .
【００２９】さらに、上記内側触媒層１２及び外側触媒
層１３にはＢａが含浸法によって担持されている。従っ
て、外側触媒層１３の上記Ｒｈ／Ｃｅ・Ｚｒ・Ｎｄ成分
は、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物にＲｈ及びＢａが担持さ
れたものになっている。すなわち、（Ｒｈ＋Ｂａ）／Ｃ
ｅ・Ｚｒ・Ｎｄ成分となっている。Further, Ba is supported on the inner catalyst layer 12 and the outer catalyst layer 13 by an impregnation method. Therefore, the Rh / Ce.Zr.Nd component of the outer catalyst layer 13 is a Ce.Zr.Nd composite oxide carrying Rh and Ba. That is, (Rh + Ba) / C
It is an e · Zr · Nd component.
【００３０】上記酸化セリウム及びＣｅ・Ｚｒ・Ｎｄ複合
酸化物は、いずれも酸素吸蔵物質として働く。上記アル
ミナには、その熱劣化を抑制するためにＬａを少量（５
％）添加している。また、バインダとしては、耐熱性向
上のためにジルコニアを用いている。The above cerium oxide and Ce / Zr / Nd composite oxide both function as oxygen storage substances. The above alumina contains a small amount of La (5
%) Is added. As the binder, zirconia is used to improve heat resistance.
【００３１】＜三元触媒８の製法＞次に上記三元触媒８
の製法を説明する。<Production Method of Three-Way Catalyst 8> Next, the above three-way catalyst 8
The manufacturing method of is explained.
【００３２】−内側触媒コート層の形成−
Ｌａを５質量％添加してなる活性アルミナ粉末に、硝酸
パラジウム水溶液を滴下し、５００℃で乾燥・焼成する
ことにより、Ｐｄ／アルミナ触媒粉を得る。-Formation of Inner Catalyst Coat Layer- Pd / alumina catalyst powder is obtained by dropping an aqueous palladium nitrate solution onto activated alumina powder obtained by adding 5% by mass of La, and drying and firing at 500 ° C.
【００３３】上記触媒粉と酸化セリウムとＣｅ・Ｚｒ・Ｎ
ｄ複合酸化物とバインダ（硝酸ジルコニル）とを混合
し、これに水と硝酸とを加え、ディスパーサで混合撹拌
してスラリーを得る。このスラリーにコージェライト製
ハニカム担体１１を浸し、引き上げて余分なスラリーを
エアブローで除去する操作を繰り返すことにより、所定
量のスラリーを当該担体にコーティングする。しかる
後、当該ハニカム担体を常温から５００℃になるまで一
定の昇温速度で１．５時間をかけて昇温し、その温度に
２時間保持する（乾燥・焼成）ことにより、内側触媒コ
ート層を形成する。The above catalyst powder, cerium oxide, Ce.Zr.N.
The d composite oxide and a binder (zirconyl nitrate) are mixed, water and nitric acid are added thereto, and the mixture is stirred with a disperser to obtain a slurry. By dipping the cordierite honeycomb carrier 11 in this slurry, pulling it up, and removing excess slurry by air blowing, the carrier is coated with a predetermined amount of the slurry. Thereafter, the honeycomb carrier is heated from room temperature to 500 ° C. at a constant temperature rising rate over 1.5 hours and kept at that temperature for 2 hours (drying and firing), whereby the inner catalyst coating layer is formed. To form.
【００３４】−外側触媒コート層の形成−
Ｌａを５質量％添加してなる活性アルミナ粉末に、ジニ
トロジアミン白金硝酸塩の水溶液を滴下し、５００℃で
乾燥・焼成することにより、Ｐｔ／アルミナ触媒粉を得
る。また、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物に、硝酸ロジウム
水溶液を滴下し、５００℃で乾燥・焼成することによ
り、Ｒｈ／Ｃｅ・Ｚｒ・Ｎｄ触媒粉を得る。-Formation of Outer Catalyst Coat Layer- Pt / alumina catalyst powder is obtained by adding an aqueous solution of dinitrodiamine platinum nitrate dropwise to activated alumina powder obtained by adding 5% by mass of La and drying and firing at 500 ° C. To get Further, an Rh / Ce.Zr.Nd catalyst powder is obtained by dropping an aqueous rhodium nitrate solution onto the Ce.Zr.Nd composite oxide and drying and firing at 500 ° C.
【００３５】上記Ｐｔ／アルミナ触媒粉とＲｈ／Ｃｅ・
Ｚｒ・Ｎｄ触媒粉とバインダ（硝酸ジルコニル）とを混
合し、これに水と硝酸とを加え、ディスパーサで混合撹
拌してスラリーを得る。このスラリーに上記内側触媒コ
ート層を形成したコージェライト製ハニカム担体１１を
浸し、引き上げて余分なスラリーをエアブローで除去す
る操作を繰り返すことにより、所定量のスラリーを当該
担体にコーティングする。しかる後、当該ハニカム担体
を常温から５００℃になるまで一定の昇温速度で１．５
時間をかけて昇温し、その温度に２時間保持する（乾燥
・焼成）ことにより、外側触媒コート層を形成する。The above Pt / alumina catalyst powder and Rh / Ce.
Zr.Nd catalyst powder and a binder (zirconyl nitrate) are mixed, water and nitric acid are added thereto, and the mixture is stirred with a disperser to obtain a slurry. The operation of dipping the cordierite honeycomb carrier 11 having the inner catalyst coating layer formed thereon in this slurry and pulling it up to remove excess slurry by air blow is repeated to coat a predetermined amount of the slurry on the carrier. After that, the honeycomb carrier is heated at a constant temperature rising rate from room temperature to 500 ° C. for 1.5 times.
The outer catalyst coat layer is formed by raising the temperature over time and maintaining the temperature for 2 hours (drying and firing).
【００３６】−Ｂａの含浸担持−
以上のようにしてハニカム担体１１に形成された内側触
媒コート層と外側触媒コート層に酢酸バリウムの水溶液
を含浸させる。しかる後、当該ハニカム担体を常温から
２００℃まで略一定の昇温速度で１．５時間をかけて昇
温し、その温度に２時間保持し（乾燥）、２００℃から
５００℃になるまで略一定の昇温速度で４時間をかけて
昇温し、その温度に２時間保持する（焼成）。-Impregnation and Support of Ba- The inner catalyst coat layer and the outer catalyst coat layer formed on the honeycomb carrier 11 are impregnated with an aqueous solution of barium acetate. After that, the honeycomb carrier is heated from room temperature to 200 ° C. at a substantially constant temperature rising rate for 1.5 hours, and is kept at that temperature for 2 hours (drying) until it reaches 200 ° C. to 500 ° C. The temperature is raised at a constant heating rate over 4 hours, and the temperature is maintained for 2 hours (calcination).
【００３７】＜実施例＞上記製法によって次の構成の三
元触媒を得た。<Example> A three-way catalyst having the following constitution was obtained by the above production method.
【００３８】−内側触媒層− Ｐｄ／アルミナ成分担持量；６３．５２９ｇ／Ｌ （Ｐｄ担持量；４．０９１ｇ／Ｌ） 酸化セリウム担持量；４．７７０ｇ／Ｌ Ｃｅ・Ｚｒ・Ｎｄ複合酸化物担持量；４．７７０ｇ／Ｌ ジルコニアバインダ担持量；７．１２０ｇ／Ｌ −外側触媒層− Ｐｔ／アルミナ成分担持量；２５．５８３ｇ／Ｌ （Ｐｔ担持量；０．１３６ｇ／Ｌ） Ｒｈ／Ｃｅ・Ｚｒ・Ｎｄ成分担持量；５６．１１９ｇ／Ｌ （Ｒｈ担持量；０．２７３ｇ／Ｌ） ジルコニアバインダ担持量；９．０８ｇ／Ｌ −Ｂａ− Ｂａ担持量；１１．００ｇ／Ｌ なお、担持量はハニカム担体１Ｌ当たりの量である。-Inner catalyst layer- Amount of Pd / alumina component carried; 63.529 g / L (Amount of Pd supported: 4.091 g / L) Cerium oxide supported amount; 4.770 g / L Ce / Zr / Nd complex oxide loading: 4.770 g / L Zirconia binder loading amount; 7.120 g / L -Outer catalyst layer- Amount of Pt / alumina component supported; 25.583 g / L (Amount of Pt carried: 0.136 g / L) Rh / Ce / Zr / Nd component loading: 56.119 g / L (Amount of Rh carried: 0.273 g / L) Zirconia binder loading amount: 9.08 g / L -Ba- Ba supported amount: 11.00 g / L Note that the supported amount is the amount per 1 L of the honeycomb carrier.
【００３９】＜比較例＞Ｃｅ・Ｚｒ・Ｎｄ複合酸化物に代
えて酸化セリウムを用いる他は上記実施例と同じ条件及
び方法で比較例触媒を調製した。<Comparative Example> A comparative catalyst was prepared under the same conditions and methods as those of the above-mentioned Examples except that cerium oxide was used instead of the Ce.Zr.Nd composite oxide.
【００４０】＜評価テスト＞上記実施例及び比較例の触
媒をエンジンの排気管に取り付け、ベンチエージングを
行なった後、ＦＴＰテストモード（トータル）でのＨ
Ｃ、ＣＯ及びＮＯｘ各々の排出量を測定した。ベンチエ
ージングは、触媒入口の排気ガス温度が６６０℃となる
低負荷運転と、同温度が８８０℃となる高負荷運転とを
１分間ずつ交互に繰り返すというサイクルを２０時間行
ない、その間、Ｐを添加したエンジンオイルを吸気マニ
ホールドにポンプで供給し続ける、というものである。
触媒には数万ｋｍ走行に相当するＰが与えられるように
した。<Evaluation Test> After the catalysts of the above-mentioned Examples and Comparative Examples were attached to the exhaust pipe of the engine and bench aging was performed, H in the FTP test mode (total) was used.
Emissions of C, CO and NOx were measured. In bench aging, a low load operation in which the exhaust gas temperature at the catalyst inlet is 660 ° C. and a high load operation in which the exhaust gas temperature is 880 ° C. are alternately repeated for 1 minute each for 20 hours, during which P is added. The engine oil is continuously pumped to the intake manifold.
The catalyst was provided with P corresponding to tens of thousands of km travel.
【００４１】結果は図３に示されている。同図のＣｅ・
Ｚｒ・Ｎｄ複合酸化物は実施例に係るものであり、酸化
セリウムは比較例に係るものである。なお、ＨＣ排出量
は１０倍に拡大している。同図によれば、ＨＣ、ＣＯ及
びＮＯｘのいずれも実施例の方が比較例よりも少なくな
っている。これは、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物の効果に
よると認められる。The results are shown in FIG. Ce in the figure
The Zr.Nd composite oxide is related to the example, and the cerium oxide is related to the comparative example. Note that the amount of HC emissions has expanded tenfold. According to the figure, the amount of HC, CO, and NOx of the example is smaller than that of the comparative example. It is recognized that this is due to the effect of the Ce-Zr-Nd composite oxide.
【００４２】すなわち、実施例の場合、Ｃｅ・Ｚｒ・Ｎｄ
複合酸化物は、酸化セリウムに比して耐熱性が高いこと
から、ベンチエージング後も高い酸素吸蔵能を維持し、
その結果、このＣｅ・Ｚｒ・Ｎｄ複合酸化物に担持されて
いるＲｈの活性の低下も少ない、と考えられる。しか
も、ＢａによってＲｈのシンタリングが抑制されるとと
もに、触媒のＰ被毒量が少なくなる。このため、実施例
では、ベンチエージング後のＨＣ、ＣＯ及びＮＯｘの排
出量が比較例よりも少なくなっていると考えられる。That is, in the case of the embodiment, Ce.Zr.Nd
Since the composite oxide has higher heat resistance than cerium oxide, it maintains a high oxygen storage capacity even after bench aging,
As a result, it is considered that the activity of Rh supported on this Ce / Zr / Nd composite oxide is not significantly reduced. Moreover, Ba suppresses the sintering of Rh and reduces the amount of P poisoning of the catalyst. Therefore, it is considered that the exhaust amount of HC, CO, and NOx after bench aging is smaller in the example than in the comparative example.
【００４３】＜Ｂａ担持量について＞
−テスト１−
上記実施例に関し、そのＢａ担持量が０．７２ｇ／Ｌ、
１１．１ｇ／Ｌ、１４．５ｇ／Ｌ、及び１９．３ｇ／Ｌ
の各触媒を調製し、各々について先と同様のベンチエー
ジングを施した後、ＦＴＰテストモード（トータル）で
のＨＣ及びＮＯｘ各々の排出量を測定した。結果は図４
に示されている。<Regarding Ba Carrying Amount> -Test 1-Regarding the above example, the Ba carrying amount was 0.72 g / L,
11.1 g / L, 14.5 g / L, and 19.3 g / L
Each catalyst was prepared, and the same bench aging as described above was applied to each catalyst, and then the emission amounts of HC and NOx in the FTP test mode (total) were measured. The result is shown in Figure 4.
Is shown in.
【００４４】同図によれば、Ｂａ担持量の大小はＨＣ排
出量にはそれほど影響を与えないが（なお、ＣＯ排出量
にもそれほど影響を与えないことを確認している）、Ｎ
Ｏｘ排出量には大きな影響を与えている。具体的には、
Ｂａ担持量が１０〜１５ｇ／Ｌ程度であるときのＮＯｘ
排出量が最も少なく、これよりもＢａ担持量が少なくな
る場合、並びに多くなる場合のいずれもＮＯｘ排出量が
多くなっている。According to the figure, although the amount of carried Ba does not affect the HC emission amount so much (it is confirmed that it does not affect the CO emission amount too much), N
It has a great influence on Ox emissions. In particular,
NOx when the amount of carried Ba is about 10 to 15 g / L
The NOx emission amount is large both when the emission amount is the smallest and when the carried amount of Ba is smaller or larger than that.
【００４５】Ｂａ担持量１５ｇ／Ｌ以下の範囲におい
て、Ｂａ担持量が多くなるに従ってＮＯｘ排出量は少な
くなっているのは、Ｂａによる触媒の耐Ｐ被毒性の向上
効果によると考えられる。これに対して、Ｂａ担持量が
１５ｇ／Ｌを越えて多くなると、Ｂａが貴金属、その他
の触媒成分を覆ってその活性を低下させるために、ある
いはハニカム担体１１が脆くなって触媒層が剥落するた
めに、ＮＯｘ排出量が多くなっているものと考えられ
る。The reason why the NOx emission amount decreases as the Ba loading amount increases in the range where the Ba loading amount is 15 g / L or less is considered to be due to the effect of improving the P poisoning resistance of the catalyst by Ba. On the other hand, when the supported amount of Ba exceeds 15 g / L and increases, Ba covers the noble metal and other catalyst components and reduces the activity thereof, or the honeycomb carrier 11 becomes brittle and the catalyst layer peels off. Therefore, it is considered that the NOx emission amount is increasing.
【００４６】−テスト２−
上記実施例に関し、そのＢａ担持量が０ｇ／Ｌ、１１ｇ
／Ｌ、２２ｇ／Ｌ、及び３０ｇ／Ｌの各触媒を調製し、
各々についてエンジンエージングを施した後、リグテス
トでＨＣ、ＣＯ及びＮＯｘの浄化に関するＴ５０、Ｃ４
００及びＣ５００を測定した。Test 2-Regarding the above embodiment, the amount of Ba carried is 0 g / L and 11 g.
/ L, 22 g / L, and 30 g / L of each catalyst were prepared,
After subjecting each to engine aging, T50, C4 regarding purification of HC, CO and NOx by rig test
00 and C500 were measured.
【００４７】エンジンエージングは、エンジンの排気管
に触媒を装着し、該触媒の温度が９００℃になるように
エンジンを１００時間運転し、該運転期間中、Ｐを添加
したエンジンオイルを吸気マニホールドにポンプで供給
し続ける、というものである。In engine aging, a catalyst is attached to the exhaust pipe of the engine, the engine is operated for 100 hours so that the temperature of the catalyst becomes 900 ° C., and engine oil containing P is supplied to the intake manifold during the operation period. It continues to supply with a pump.
【００４８】リグテストは、上記エンジンエージングを
施した触媒を排気管から取り外して直径２．５４ｃｍ、
長さ５ｃｍの円筒型に切り出し、これを固定床流通式反
応評価装置に取り付けて行なった。模擬排気ガスはＡ／
Ｆ＝１４．７±０．９とした。すなわち、Ａ／Ｆ＝１
４．７のメインストリームガスを定常的に流しつつ、所
定量の変動用ガスを１Ｈｚでパルス状に添加することに
より、Ａ／Ｆを±０．９の振幅で強制的に振動させた。
Ａ／Ｆ＝１４．７のメインストリームガスの組成は次の
通りである。模擬排気ガスの触媒への流入量は２５Ｌ／
分とした。
（メインストリームガス）
ＣＯ2；１３．９％，Ｏ2；０．６％，ＣＯ；０．６％，
Ｈ2；０．２％，Ｃ3Ｈ6；０．０５６％，ＮＯ；０．１
％，Ｈ2Ｏ；１０％，残りＮ2
上記変動用ガスとしては、Ａ／Ｆをリーン側（Ａ／Ｆ＝
１５．６）へ振らせる場合にはＯ2を用い、リッチ側
（Ａ／Ｆ＝１３．９）へ振らせる場合にはＨ2及びＣＯ
を用いた。In the rig test, the catalyst aged above was removed from the exhaust pipe and the diameter was 2.54 cm.
It was cut into a cylindrical shape having a length of 5 cm, and this was attached to a fixed-bed flow-type reaction evaluation apparatus to carry out. Simulated exhaust gas is A /
F = 14.7 ± 0.9. That is, A / F = 1
While constantly flowing the mainstream gas of 4.7, the A / F was forcibly oscillated with an amplitude of ± 0.9 by adding a predetermined amount of the fluctuating gas in a pulse shape at 1 Hz.
The composition of the mainstream gas with A / F = 14.7 is as follows. The flow rate of simulated exhaust gas into the catalyst is 25 L /
Minutes (Main stream gas) CO 2 ; 13.9%, O 2 ; 0.6%, CO; 0.6%,
H 2 ; 0.2%, C 3 H 6 ; 0.056%, NO; 0.1
%, H 2 O; 10%, remaining N 2 As the fluctuation gas, A / F is on the lean side (A / F =
O 2 is used to swing to 15.6), and H 2 and CO are used to swing to the rich side (A / F = 13.9).
Was used.
【００４９】Ｔ５０は、模擬排気ガス温度を漸次上昇さ
せていき、触媒下流で検出されるガスの当該成分（Ｈ
Ｃ、ＣＯ又はＮＯｘ）濃度が該触媒に流入するガスの当
該成分濃度の半分になった時点（浄化率が５０％になっ
た時点）の触媒入口ガス温度（ライトオフ温度）であ
る。At T50, the temperature of the simulated exhaust gas is gradually raised, and the component (H) of the gas detected downstream of the catalyst is increased.
It is the catalyst inlet gas temperature (light-off temperature) at the time when the concentration of C, CO, or NOx) becomes half the concentration of the component of the gas flowing into the catalyst (at the time when the purification rate reaches 50%).
【００５０】Ｃ４００は、触媒入口での模擬排気ガス温
度が４００℃であるときの各成分の浄化率であり、Ｃ５
００は、触媒入口での模擬排気ガス温度が５００℃であ
るときの各成分の浄化率である。C400 is the purification rate of each component when the simulated exhaust gas temperature at the catalyst inlet is 400 ° C., and C5
00 is the purification rate of each component when the simulated exhaust gas temperature at the catalyst inlet is 500 ° C.
【００５１】Ｔ５０の結果は図５に示されている。より
厳しい耐久条件下では、ＨＣ、ＣＯ及びＮＯｘのいずれ
についても、Ｂａ担持量が２２ｇ／Ｌになるまでは該Ｂ
ａ担持量が多くなるに従ってＴ５０が低下している。す
なわち、低温活性が向上している。これはＢａによるＰ
被毒の抑制、並びにＲｈのシンタリング抑制効果による
ものと考えられる。Ｂａ担持量が３０ｇ／Ｌになると、
Ｔ５０が少し悪化している（高くなっている）のは、Ｂ
ａが触媒金属（Ｐｄ、Ｐｔ、Ｒｈ）を覆ってそれらの活
性を若干低下させたためと考えられる。The T50 results are shown in FIG. Under more severe endurance conditions, for any of HC, CO, and NOx, the B content up to the supported amount of Ba reaches 22 g / L.
The T50 decreases as the amount of a carried increases. That is, the low temperature activity is improved. This is P by Ba
This is considered to be due to the poisoning suppression effect and the Rh sintering suppression effect. When the amount of Ba carried becomes 30 g / L,
A little worse (higher) T50 is B
It is considered that “a” covered the catalytic metals (Pd, Pt, Rh) and slightly reduced their activities.
【００５２】Ｃ４００の結果は図６に示され、Ｃ５００
の結果は図７に示されている。Ｃ４００及びＣ５００に
関しても、Ｔ５０と同様に、ＨＣ、ＣＯ及びＮＯｘのい
ずれについても、Ｂａ担持量が多くなるに従って浄化率
が高くなっている（高温活性が向上している）が、Ｂａ
担持量が３０ｇ／Ｌになると、少し低下している。その
理由はＴ５０の場合と同様と考えられる。The results for C400 are shown in FIG.
The results are shown in FIG. Regarding C400 and C500, as in the case of T50, the purification rate increases as the amount of carried Ba increases for all of HC, CO and NOx.
When the carried amount becomes 30 g / L, it is slightly decreased. The reason is considered to be similar to the case of T50.
【００５３】テスト１の場合、Ｂａ担持量が１９．３ｇ
／Ｌであるときは、１１．１ｇ／ＬであるときよりもＮ
Ｏｘ浄化性能が低下しているのに対して、テスト２の場
合はＢａ担持量が２２ｇ／Ｌのときの方が１１ｇ／Ｌの
ときよりもＨＣ、ＣＯ及びＮＯｘの浄化性能が良くなっ
ている。この理由は、テスト２はテスト１よりもエージ
ング条件が厳しくなっているためと推察される。In the case of test 1, the amount of carried Ba was 19.3 g.
/ L is more N than 11.1 g / L
While the Ox purification performance is lowered, in the case of Test 2, the purification performance of HC, CO and NOx is better when the amount of carried Ba is 22 g / L than when it is 11 g / L. . The reason for this is presumed that the aging condition of Test 2 is more severe than that of Test 1.
【００５４】すなわち、Ｂａの添加は、触媒金属を覆っ
てその活性を低下させる、ハニカム担体を脆くして触媒
層の剥離を招き易くなる、という問題があるものの、エ
ージング条件が厳しくなると、Ｐ被毒及びＲｈのシンタ
リングの問題が大きくなるため、Ｂａ担持量が多い方が
排気ガスの浄化性能の点では有利になっている、という
ことである。That is, although the addition of Ba has problems that it covers the catalytic metal to reduce its activity and makes the honeycomb carrier brittle and easily peels off the catalyst layer, if the aging condition becomes strict, it causes P Since the problem of the poisoning and the sintering of Rh becomes large, the larger the amount of Ba carried, the more advantageous in terms of the exhaust gas purification performance.
【００５５】上記テスト１，２の結果から、Ｂａ担持量
は、少なすぎないように、また多すぎないように５〜３
０ｇ／Ｌ程度とすることが好ましい、ということができ
る。また、テスト１の結果によれば、Ｂａ担持量を１０
〜１５ｇ／Ｌとすることが好ましい、ということができ
るが、Ｐ被毒及びＲｈのシンタリングの問題が強く懸念
される場合は、テスト２の結果から、Ｂａ担持量を２２
ｇ／Ｌ程度まで高めることが好ましい、ということがで
きる。From the results of tests 1 and 2 above, the amount of Ba carried should be 5 to 3 so as not to be too small or too large.
It can be said that it is preferably about 0 g / L. Moreover, according to the result of the test 1, the amount of carried Ba is 10
It can be said that it is preferable to set the amount to 15 g / L, but if the problems of P poisoning and sintering of Rh are strongly concerned, from the result of Test 2, the Ba loading amount should be 22.
It can be said that it is preferable to increase to about g / L.
【図１】本発明の実施形態に係るエンジンの排気ガス浄
化装置を示す図。FIG. 1 is a diagram showing an exhaust gas purifying apparatus for an engine according to an embodiment of the present invention.
【図２】同実施形態に係る触媒構造を示す断面図。FIG. 2 is a cross-sectional view showing a catalyst structure according to the same embodiment.
【図３】本発明の実施例と比較例のベンチエージング後
の排気ガス浄化性能を示すグラフ図。FIG. 3 is a graph showing the exhaust gas purification performance after bench aging of the example of the present invention and the comparative example.
【図４】本発明の実施例におけるＢａ担持量とＨＣ及び
ＮＯｘの各排出量との関係を示すグラフ図。FIG. 4 is a graph showing the relationship between the carried amount of Ba and the respective emission amounts of HC and NOx in the example of the present invention.
【図５】本発明の実施例におけるＢａ担持量とＨＣ、Ｃ
Ｏ及びＮＯｘの浄化に関するＴ５０との関係を示すグラ
フ図。FIG. 5: Ba loading amount and HC, C in the example of the present invention
The graph figure which shows the relationship with T50 regarding purification of O and NOx.
【図６】本発明の実施例におけるＢａ担持量とＨＣ、Ｃ
Ｏ及びＮＯｘのＣ４００との関係を示すグラフ図。FIG. 6 shows the amounts of carried Ba and HC and C in the example of the present invention.
The graph figure which shows the relationship between O and C400 of NOx.
【図７】本発明の実施例におけるＢａ担持量とＨＣ、Ｃ
Ｏ及びＮＯｘのＣ５００との関係を示すグラフ図。FIG. 7: Ba loading amount and HC, C in the example of the present invention
The graph figure which shows the relationship between C500 of O and NOx.
１ エンジン ７ 排気通路 ８ 三元触媒 １１ 担体 １２ 内側触媒層 １３ 外側触媒層 1 engine 7 exhaust passage 8 three-way catalyst 11 Carrier 12 Inner catalyst layer 13 Outer catalyst layer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 藤田 克幸 広島県高田郡向原町360番地 東京濾器株 式会社内 (72)発明者 岩国 秀治 広島県安芸郡府中町新地３番１号 マツダ 株式会社内 (72)発明者 重津 雅彦 広島県安芸郡府中町新地３番１号 マツダ 株式会社内 (72)発明者 高見 明秀 広島県安芸郡府中町新地３番１号 マツダ 株式会社内 Ｆターム(参考） 4D048 AA06 AA13 AA18 AB05 BA03X BA08X BA15X BA18X BA19X BA30X BA31X BA33X BA41X BA42X BB02 BB16 EA04 4G069 AA03 AA08 BA01A BA01B BA13B BB06A BB06B BC13A BC13B BC43A BC43B BC44A BC44B BC51A BC51B BC71A BC71B BC72A BC72B BC75A BC75B CA03 CA09 EA19 EC28 EE06 FA02 FB14 FB19 FC08 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Katsuyuki Fujita 360 Mukohara Town, Takada District, Hiroshima Prefecture Inside the company (72) Inventor Shuji Iwakuni 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Within the corporation (72) Inventor Masahiko Shigets 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Within the corporation (72) Inventor Akihide Takami 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Within the corporation F-term (reference) 4D048 AA06 AA13 AA18 AB05 BA03X BA08X BA15X BA18X BA19X BA30X BA31X BA33X BA41X BA42X BB02 BB16 EA04 4G069 AA03 AA08 BA01A BA01B BA13B BB06A BB06B BC13A BC13B BC43A BC43B BC44A BC44B BC51A BC51B BC71A BC71B BC72A BC72B BC75A BC75B CA03 CA09 EA19 EC28 EE06 FA02 FB14 FB19 FC08
Claims (5)
触媒において、 さらに、Ｃｅ・Ｚｒ・Ｎｄ複合酸化物を含有し、 上記Ｃｅ・Ｚｒ・Ｎｄ複合酸化物に上記Ｒｈ及びＢａが担
持されていることを特徴とする排気ガス浄化用触媒。1. An exhaust gas purifying catalyst containing Rh and Ba, further containing a Ce.Zr.Nd composite oxide, wherein the Ce.Zr.Nd composite oxide is loaded with the Rh and Ba. Exhaust gas purification catalyst characterized by
用触媒において、 上記Ｒｈ、Ｂａ及びＣｅ・Ｚｒ・Ｎｄ複合酸化物は担体に
担持されていて、該担体１Ｌ当たりのＢａ担持量が５〜
３０ｇであることを特徴とする排気ガス浄化用触媒。2. The exhaust gas purifying catalyst according to claim 1, wherein the Rh, Ba, and Ce.Zr.Nd composite oxide are supported on a carrier, and the amount of supported Ba per 1 L of the carrier is 5-
An exhaust gas purifying catalyst, which is 30 g.
排気ガス浄化用触媒において、 さらに、Ｐｔ及びアルミナを含有し、 上記Ｒｈ及びＰｔは、前者が上記Ｃｅ・Ｚｒ・Ｎｄ複合酸
化物に、後者が上記アルミナに互いに分かれて担持さ
れ、 上記Ｒｈを担持したＣｅ・Ｚｒ・Ｎｄ複合酸化物と、上記
Ｐｔを担持したアルミナとが混合した状態で含まれてい
ることを特徴とする排気ガス浄化用触媒。3. The exhaust gas purifying catalyst according to claim 1 or 2, further comprising Pt and alumina, wherein the Rh and Pt are the former Ce—Zr—Nd composite oxide. In the exhaust gas, the latter is separately supported on the alumina, and the Ce-Zr-Nd composite oxide supporting the Rh and the alumina supporting the Pt are contained in a mixed state. Gas purification catalyst.
いて、 上記複数の触媒層のうち内側に位置する触媒層は、アル
ミナにＰｄが担持されてなる成分と、酸素吸蔵物質とを
含有し、 上記内側触媒層よりも外側に位置する触媒層は、Ｃｅ・
Ｚｒ・Ｎｄ複合酸化物にＲｈ及びＢａが担持されてなる
成分を含有することを特徴とする排気ガス浄化用触媒。4. A plurality of catalyst layers are formed in layers on a carrier, and the inner catalyst layer of the plurality of catalyst layers comprises a component in which Pd is supported on alumina and an oxygen storage material. The catalyst layer that is contained and is located outside the inner catalyst layer is Ce.
An exhaust gas purifying catalyst comprising a Zr.Nd complex oxide containing Rh and Ba supported thereon.
物を含有する排気ガス浄化用触媒の製造方法であって、 上記Ｃｅ・Ｚｒ・Ｎｄ複合酸化物に上記Ｒｈを担持させて
焼成し、 上記Ｒｈを担持したＣｅ・Ｚｒ・Ｎｄ複合酸化物に上記Ｂ
ａを担持させることを特徴とする排気ガス浄化用触媒の
製造方法。5. A method for producing an exhaust gas purifying catalyst containing Rh, Ba, and a Ce / Zr / Nd composite oxide, wherein the Ce / Zr / Nd composite oxide is supported on the Rh, and then calcined. The above-mentioned Rh-supported Ce / Zr / Nd composite oxide is added to the above B
A method for producing an exhaust gas purifying catalyst, which comprises supporting a.
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| EP1520616A1 (en) * | 2003-09-30 | 2005-04-06 | Tokyo Roki Co., Ltd. | Exhaust gas purifying catalyst |
| JP2006035029A (en) * | 2004-07-23 | 2006-02-09 | Mazda Motor Corp | Catalyst for purification of exhaust gas |
| JP2006035043A (en) * | 2004-07-23 | 2006-02-09 | Mazda Motor Corp | Catalyst for purifying exhaust gas |
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| WO2011080567A1 (en) | 2010-01-04 | 2011-07-07 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying catalyst |
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