JPH08117602A - Catalyst for purifying exhaust gas - Google Patents
Catalyst for purifying exhaust gasInfo
- Publication number
- JPH08117602A JPH08117602A JP6256976A JP25697694A JPH08117602A JP H08117602 A JPH08117602 A JP H08117602A JP 6256976 A JP6256976 A JP 6256976A JP 25697694 A JP25697694 A JP 25697694A JP H08117602 A JPH08117602 A JP H08117602A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- supported
- metal
- alumina
- exhaust gas
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は排ガス浄化用触媒に関
し、詳しくはリーン側の排ガスであっても窒素酸化物
（ＮＯX ）を効率よく浄化できる触媒に関する。The present invention relates to an exhaust gas purification catalyst, and particularly relates to a catalyst nitrogen oxides is the exhaust gas of the lean side (NO X) can be efficiently purified.
【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、ＣＯ及びＨＣの酸化とＮＯX の還元とを同時に行
って排ガスを浄化する三元触媒が用いられている。この
ような触媒としては、例えばコージェライトなどの耐熱
性担体にγ−アルミナからなる担持層を形成し、その担
持層にＰｔ，Ｐｄ，Ｒｈなどの触媒貴金属を担持させた
ものが広く知られている。2. Description of the Related Art Conventionally, a three-way catalyst for purifying exhaust gas by simultaneously oxidizing CO and HC and reducing NO X has been used as an exhaust gas purification catalyst for automobiles. As such a catalyst, for example, a catalyst in which a supporting layer made of γ-alumina is formed on a heat resistant carrier such as cordierite and a catalytic precious metal such as Pt, Pd, Rh is supported on the supporting layer is widely known. There is.
【０００３】ところで、このような排ガス浄化用触媒の
浄化性能は、エンジンの空燃比（Ａ／Ｆ）によって大き
く異なる。すなわち、空燃比の大きい、つまり燃料濃度
が希薄なリーン側では排ガス中の酸素量が多くなり、Ｃ
ＯやＨＣを浄化する酸化反応が活発である反面ＮＯX を
浄化する還元反応が不活発になる。逆に空燃比の小さ
い、つまり燃料濃度が濃いリッチ側では排ガス中の酸素
量が少なくなり、酸化反応は不活発となるが還元反応は
活発になる。By the way, the purification performance of such an exhaust gas purifying catalyst greatly differs depending on the air-fuel ratio (A / F) of the engine. That is, on the lean side where the air-fuel ratio is large, that is, where the fuel concentration is lean, the amount of oxygen in the exhaust gas increases, and C
While the oxidation reaction for purifying O and HC is active, the reduction reaction for purifying NO X is inactive. On the contrary, on the rich side where the air-fuel ratio is small, that is, the rich side where the fuel concentration is high, the amount of oxygen in the exhaust gas is small, and the oxidation reaction becomes inactive but the reduction reaction becomes active.
【０００４】一方、自動車の走行において、市街地走行
の場合には加速・減速が頻繁に行われ、空燃比はストイ
キ（理論空燃比）近傍からリッチ状態までの範囲内で頻
繁に変化する。このような走行における低燃費化の要請
に応えるには、なるべく酸素過剰の混合気を供給するリ
ーン側での運転が必要となる。したがってリーン側にお
いてもＮＯX を十分に浄化できる触媒の開発が望まれて
いる。On the other hand, when driving an automobile, acceleration and deceleration are frequently performed in urban areas, and the air-fuel ratio frequently changes within the range from near stoichiometric (theoretical air-fuel ratio) to the rich state. In order to meet the demand for low fuel consumption in such traveling, it is necessary to operate on the lean side to supply an air-fuel mixture with excess oxygen as much as possible. Therefore, it is desired to develop a catalyst that can sufficiently purify NO X even on the lean side.
【０００５】そこで本願出願人は、先にアルカリ土類金
属とＰｔをアルミナなどの多孔質担体に担持した排ガス
浄化用触媒を提案している（特開平５−３１７６５２号
公報）。この触媒によれば、リーン時にＮＯX はアルカ
リ土類金属に吸着され、それがストイキ〜リッチ時にＨ
ＣやＣＯなどの還元性ガスと反応して浄化されるため、
リーン側においてもＮＯX の浄化性能に優れている。Therefore, the applicant of the present application has previously proposed an exhaust gas purifying catalyst in which an alkaline earth metal and Pt are supported on a porous carrier such as alumina (Japanese Patent Laid-Open No. 5-317652). According to this catalyst, when lean, NO X is adsorbed by the alkaline earth metal, and when it is stoichiometric-rich, it becomes H.
Since it is purified by reacting with reducing gas such as C and CO,
Also on the lean side, it has excellent NO X purification performance.
【０００６】特開平５−３１７６５２号公報に開示され
た触媒では、例えばバリウムが単独酸化物として担体に
担持され、それがＮＯX と反応して硝酸バリウム（Ｂａ
（ＮＯ3 ）2 ）を生成することでＮＯX を吸着するもの
と考えられている。In the catalyst disclosed in Japanese Unexamined Patent Publication No. 5-317652, for example, barium is supported as a single oxide on a carrier, which reacts with NO x to form barium nitrate (Ba).
It is considered that NO x is adsorbed by producing (NO 3 ) 2 ).
【０００７】[0007]
【発明が解決しようとする課題】ところが排ガス中に
は、燃料中に含まれる硫黄（Ｓ）が燃焼して生成したＳ
Ｏ X が含まれ、それが酸素過剰雰囲気中で触媒金属によ
り酸化され、また水蒸気の作用も加わって、亜硫酸イオ
ンや硫酸イオンが生成する。そして、これらがバリウム
と反応して亜硫酸バリウムや硫酸バリウムが生成し、こ
れによりバリウムのＮＯX 吸収作用が阻害されて浄化性
能が低下する硫黄被毒が生じることが明らかとなった。
また、アルミナなどの多孔質担体はＳＯX を吸着しやす
いという性質があることから、上記硫黄被毒が促進され
るという問題がある。[Problems to be Solved by the Invention] However, in the exhaust gas
Is S produced by combustion of sulfur (S) contained in fuel
O XContained in the catalyst metal in an oxygen-rich atmosphere.
It is reoxidized, and the action of water vapor is added to it.
Ion and sulfate ions are generated. And these are barium
Reacts with barium sulfite or barium sulfate to produce
NO of barium by thisXAbsorption action is blocked and purification
It has become clear that sulfur poisoning occurs, which reduces performance.
Also, the porous carrier such as alumina is SOXEasy to adsorb
Because of its nature, the sulfur poisoning is promoted.
There is a problem that
【０００８】そして、このようにバリウムが亜硫酸塩や
硫酸塩となると、もはやＮＯX を吸着することができな
くなり、その結果上記触媒では、耐久後のＮＯX の浄化
性能が低下するという不具合があった。また、チタニア
はＳＯX を吸着しにくいので、アルミナ担体に代えてチ
タニア担体を用いることが想起され実験が行われた。そ
の結果、ＳＯX はチタニアには吸着されにくくそのまま
下流に流れ、触媒貴金属と直接接触したＳＯX のみが酸
化されるだけであるので被毒の程度は少ないことが明ら
かとなった。ところがチタニア担体では初期活性が低
く、耐久後のＮＯX の浄化性能も低いままであるという
致命的な不具合があることも明らかとなった。When barium becomes sulfite or sulfate as described above, NO x can no longer be adsorbed, and as a result, the catalyst has a drawback that the NO x purification performance after endurance deteriorates. It was Further, since titania hardly adsorbs SO X , it was remembered to use a titania carrier instead of an alumina carrier, and an experiment was conducted. As a result, it became clear that SO X is hardly adsorbed by titania and flows as it is, and only SO X that is in direct contact with the catalytic noble metal is oxidized, so that the degree of poisoning is small. However, it was also clarified that the titania carrier has a fatal defect that the initial activity is low and the NO x purification performance after durability is still low.
【０００９】本発明はこのような事情に鑑みてなされた
ものであり、初期のＮＯX 浄化率を確保しつつ、ＮＯX
吸収材の硫黄被毒を防止して耐久後におけるＮＯX 浄化
性能の低下を防止することを目的とする。The present invention has been made in view of the above circumstances, and it is possible to secure the initial NO x purification rate while maintaining the NO x.
The purpose of the present invention is to prevent sulfur poisoning of the absorbent material and prevent deterioration of the NO x purification performance after endurance.
【００１０】[0010]
【課題を解決するための手段】上記課題を解決する本発
明の排ガス浄化用触媒は、アルミナ担体上に、Ｔｉ−Ｚ
ｒ複合酸化物と、アルカリ金属，アルカリ土類金属及び
希土類元素から選ばれるＮＯX 吸収材と、触媒貴金属
と、を担持してなることを特徴とする。ここにおいて、
担持されるＴｉ−Ｚｒ複合酸化物はすべてが複合酸化物
である必要はなく、少なくとも一部が複合酸化物であれ
ばよい。An exhaust gas purifying catalyst of the present invention which solves the above-mentioned problems is a Ti-Z catalyst on an alumina carrier.
An r complex oxide, an NO x absorbent selected from alkali metals, alkaline earth metals and rare earth elements, and a catalytic noble metal are carried. put it here,
Not all Ti-Zr composite oxides to be supported need to be composite oxides, but at least a part thereof may be composite oxides.
【００１１】[0011]
【作用】本発明の排ガス浄化用触媒では、アルミナ担体
上にＴｉ−Ｚｒ複合酸化物が担持されている。この複合
酸化物を担持することにより、アルミナ自身の酸性度を
上げることができる。ＳＯX は酸性であるので、アルミ
ナ担体の酸性度が高まることによりＳＯX のアルミナへ
の吸着作用が低下すると考えられ、ＳＯX の吸着による
ＮＯX 吸収材の硫黄被毒が防止される。In the exhaust gas purifying catalyst of the present invention, the Ti-Zr composite oxide is supported on the alumina carrier. By supporting this composite oxide, the acidity of alumina itself can be increased. Since SO X is acidic, it is considered that the adsorption action of SO X on alumina is reduced by increasing the acidity of the alumina carrier, and sulfur poisoning of the NO X absorbent due to SO X adsorption is prevented.
【００１２】[0012]
〔発明の具体例〕Ｔｉ−Ｚｒ複合酸化物の担持量は、ア
ルミナ担体１００ｇに対して１〜８０ｇの範囲が望まし
い。複合酸化物が１ｇより少ないと硫黄被毒が生じて耐
久後のＮＯX 浄化性能が低下し、８０ｇより多くなると
初期のＮＯX 浄化性能が低下し酸化活性も低下するよう
になる。Specific Example of the Invention The amount of the Ti-Zr composite oxide supported is preferably in the range of 1 to 80 g per 100 g of the alumina carrier. When the amount of the composite oxide is less than 1 g, sulfur poisoning occurs and the NO x purification performance after endurance deteriorates, and when it exceeds 80 g, the initial NO x purification performance decreases and the oxidation activity also decreases.
【００１３】このＴｉ−Ｚｒ複合酸化物のＴｉとＺｒの
比率は、モル比でＴｉ：Ｚｒ＝１：９〜９：１の範囲が
望ましい。この範囲を外れると複合化の効果が小さくな
る傾向がある。アルカリ金属としてはリチウム、ナトリ
ウム、カリウム、ルビジウム、セシウム、フランシウム
が挙げられる。また、アルカリ土類金属とは周期表２Ａ
族元素をいい、バリウム、ベリリウム、マグネシウム、
カルシウム、ストロンチウムが挙げられる。また希土類
元素としては、スカンジウム、イットリウム、ランタ
ン、セリウム、プラセオジム、ネオジムなどが例示され
る。The molar ratio of Ti to Zr in this Ti-Zr composite oxide is preferably Ti: Zr = 1: 9 to 9: 1. If it deviates from this range, the compounding effect tends to decrease. Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium and francium. In addition, the alkaline earth metal is Periodic Table 2A.
Group elements, barium, beryllium, magnesium,
Examples include calcium and strontium. Examples of rare earth elements include scandium, yttrium, lanthanum, cerium, praseodymium, and neodymium.
【００１４】このＮＯX 吸収材の担持量は、アルミナ担
体１００ｇに対して０．０５〜０．５ｍｏｌの範囲が望
ましい。ＮＯX 吸収材が０．０５ｍｏｌより少ないとＮ
ＯX浄化性能が低下し、０．５ｍｏｌより多くなると酸
化活性が低下するようになる。触媒貴金属としては、白
金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）の
少なくとも一種が用いられる。白金又はパラジウムの担
持量は、アルミナ担体１００ｇに対して０．１〜２０．
０ｇの範囲が望ましく、０．３〜１０．０ｇの範囲が特
に好ましい。担持量が０．１ｇより少ないと初期及び耐
久後のＮＯX 浄化性能が低下し、２０．０ｇを超えて担
持しても効果が飽和し、過剰に担持された触媒貴金属の
有効利用が図れない。The amount of the NO x absorbent supported is preferably in the range of 0.05 to 0.5 mol with respect to 100 g of the alumina carrier. If the NO x absorbent is less than 0.05 mol, N
The O x purification performance deteriorates, and when it exceeds 0.5 mol, the oxidation activity comes to decrease. At least one of platinum (Pt), palladium (Pd), and rhodium (Rh) is used as the catalytic noble metal. The amount of platinum or palladium supported is 0.1 to 20.
The range of 0 g is desirable, and the range of 0.3 to 10.0 g is particularly preferable. If the supported amount is less than 0.1 g, the NO x purification performance at the initial stage and after endurance will decrease, and the effect will be saturated even if the supported amount exceeds 20.0 g, and the excessive use of the catalytic precious metal cannot be effectively utilized. .
【００１５】ロジウムの担持量は、アルミナ担体１００
ｇに対して０．００１〜１．０ｇの範囲が望ましく、
０．０５〜０．５ｇの範囲が特に好ましい。担持量が
０．００１ｇより少ないと初期及び耐久後のＮＯX 浄化
性能が低下し、１．０ｇを超えると白金あるいはパラジ
ウムの効果が逆に低下する。ロジウムの担持量は白金あ
るいはパラジウムの担持量と相対的に決定されるのが望
ましく、白金あるいはパラジウムの担持量の合計量の１
／３以下、さらに好ましくは１／５以下とするのがよ
い。The amount of rhodium supported is 100% on the alumina carrier.
The range of 0.001 to 1.0 g is desirable with respect to g,
The range of 0.05 to 0.5 g is particularly preferable. If the supported amount is less than 0.001 g, the NO x purification performance at the initial stage and after endurance deteriorates, and if it exceeds 1.0 g, the effect of platinum or palladium decreases conversely. It is desirable that the amount of rhodium supported be determined relative to the amount of platinum or palladium supported, which is 1 of the total amount of platinum or palladium supported.
It is preferably / 3 or less, and more preferably 1/5 or less.
【００１６】本発明の排ガス浄化用触媒を製造する場合
において、Ｔｉ−Ｚｒ複合酸化物、ＮＯX 吸収材、触媒
貴金属の担持順序は特に制限されないが、触媒貴金属を
アルミナ担体上により高分散担持するためには、触媒貴
金属は複合酸化物より後に担持するのが望ましい。 （実施例１）所定濃度のジニトロジアンミン白金水溶液
１Ｌ中に活性アルミナ粉末６００ｇを浸漬して攪拌し、
蒸発乾固後２５０℃で１時間焼成して、アルミナ粉末１
２０ｇに対してＰｔを２ｇ担持したＰｔ担持粉末を調製
した。In the case of producing the exhaust gas purifying catalyst of the present invention, the order of loading the Ti--Zr composite oxide, the NO x absorbent, and the catalytic noble metal is not particularly limited, but the catalytic noble metal is more highly dispersed and loaded on the alumina carrier. For this reason, it is desirable that the catalytic noble metal be supported after the complex oxide. (Example 1) 600 g of activated alumina powder was immersed in 1 L of an aqueous solution of dinitrodiammine platinum having a predetermined concentration and stirred,
After evaporating to dryness, baking at 250 ° C for 1 hour gives alumina powder 1
Pt-supported powder in which 2 g of Pt was supported with respect to 20 g was prepared.
【００１７】このＰｔ担持粉末を２−プロパノール中に
混合し、８０℃で１時間攪拌した。それを８０℃に維持
して攪拌しながら、三段階に比率を変えて、チタン酸テ
トライソプロピルとジルコニウムテトラｎ−ブトキシド
を同時に加え、８０℃で２時間攪拌を続けた。そして室
温まで冷却後濾過し、得られた粉末を乾燥後５００℃で
１時間焼成した。ＴｉとＺｒはＴｉ−Ｚｒ複合酸化物と
してアルミナ粉末に担持され、アルミナ１２０ｇに対し
て金属換算でＴｉが０．４８ｍｏｌ担持され、金属換算
でＺｒが０．１２ｍｏｌ担持されている。This Pt-supported powder was mixed in 2-propanol and stirred at 80 ° C. for 1 hour. While maintaining it at 80 ° C. and stirring, the ratio was changed in three stages, tetraisopropyl titanate and zirconium tetra-n-butoxide were added simultaneously, and stirring was continued at 80 ° C. for 2 hours. Then, the mixture was cooled to room temperature and filtered, and the obtained powder was dried and calcined at 500 ° C. for 1 hour. Ti and Zr are supported on alumina powder as a Ti-Zr composite oxide, and 0.48 mol of Ti in terms of metal is supported on 120 g of alumina, and 0.12 mol of Zr in terms of metal is supported.
【００１８】得られた粉末を所定濃度の酢酸バリウム水
溶液中に投入して攪拌し、蒸発乾固後５００℃で１時間
焼成した。これにより、アルミナ粉末１２０ｇに対して
金属換算でＢａを０．３ｍｏｌ担持した粉末を調製し
た。この粉末９７０ｇと、アルミナゾル（アルミナ含有
率１０重量％）６８０ｇと、水２９０ｇを混合してスラ
リーを調製し、コーディエライト製ハニカム担体基材を
このスラリーに浸漬後引き上げて余分なスラリーを吹き
払い、乾燥後５００℃で１時間焼成してコート層を形成
した。コート層は担体基材１Ｌに対して１２０ｇ形成さ
れ、表１に示すように担体基材１Ｌに対してＰｔが２
ｇ、Ｔｉ（金属換算）が０．４８ｍｏｌ、Ｚｒ（金属換
算）が０．１２ｍｏｌ、Ｂａ（金属換算）が０．３ｍｏ
ｌ担持された触媒が得られた。 （実施例２）実施例１と同様にして調製され、担体基材
１Ｌに対してＴｉ（金属換算）が０．３０ｍｏｌ、Ｚｒ
（金属換算）が０．３０ｍｏｌ担持されたこと以外は実
施例１と同様である。 （実施例３）実施例１と同様にして調製され、担体基材
１Ｌに対してＴｉ（金属換算）が０．１２ｍｏｌ、Ｚｒ
（金属換算）が０．４８ｍｏｌ担持されたこと以外は実
施例１と同様である。 （実施例４〜６）酢酸バリウム水溶液の代わりに、硝酸
ナトリウム、硝酸カリウム、硝酸セシウムの各水溶液を
それぞれ用いたこと以外は実施例１と同様にして、実施
例４〜６の各触媒を調製した。担体基材１Ｌに対してＮ
ａ、Ｋ及びＣｓは金属換算でそれぞれ０．３ｍｏｌ担持
されている。 （実施例７）所定濃度のジニトロジアンミン白金水溶液
１Ｌ中に活性アルミナ粉末６００ｇを浸漬して攪拌し、
蒸発乾固後２５０℃で１時間焼成して、アルミナ粉末１
２０ｇに対してＰｔを２ｇ担持したＰｔ担持粉末を調製
した。The obtained powder was put into a barium acetate aqueous solution having a predetermined concentration, stirred, evaporated to dryness, and calcined at 500 ° C. for 1 hour. As a result, a powder was prepared in which 0.3 mol of Ba in terms of metal was supported on 120 g of alumina powder. 970 g of this powder, 680 g of alumina sol (alumina content 10% by weight), and 290 g of water are mixed to prepare a slurry, and a cordierite honeycomb carrier base material is immersed in this slurry and then pulled up to blow off excess slurry. After drying, it was baked at 500 ° C. for 1 hour to form a coat layer. The coat layer was formed in an amount of 120 g per 1 L of the carrier substrate, and as shown in Table 1, Pt was 2 per 1 L of the carrier substrate.
g, Ti (metal conversion) 0.48 mol, Zr (metal conversion) 0.12 mol, Ba (metal conversion) 0.3 mo
1 supported catalyst was obtained. (Example 2) Prepared in the same manner as in Example 1, with Ti (metal conversion) being 0.30 mol and Zr based on 1 L of the carrier substrate.
The same as Example 1 except that 0.30 mol (as metal) was supported. (Example 3) Prepared in the same manner as in Example 1, with 1 L of carrier substrate containing 0.12 mol of Ti (as metal) and Zr.
The same as Example 1 except that 0.48 mol (as metal) was supported. (Examples 4 to 6) Each catalyst of Examples 4 to 6 was prepared in the same manner as in Example 1 except that sodium nitrate, potassium nitrate and cesium nitrate aqueous solutions were used instead of the barium acetate aqueous solution. . N for 1 L of carrier substrate
0.3 mol of each of a, K and Cs is carried in terms of metal. (Example 7) 600 g of activated alumina powder was immersed in 1 L of dinitrodiammine platinum aqueous solution having a predetermined concentration and stirred,
After evaporating to dryness, baking at 250 ° C for 1 hour gives alumina powder 1
Pt-supported powder in which 2 g of Pt was supported with respect to 20 g was prepared.
【００１９】このＰｔ担持粉末に、チタニアゾルとジル
コニアゾルを加え、攪拌して蒸発乾固後５００℃で１時
間焼成した。その後実施例１と同様にしてＢａを担持
し、同様にコート層を形成して実施例７の触媒とした。
ＴｉとＺｒはＴｉ−Ｚｒ複合酸化物としてアルミナ粉末
に担持され、アルミナ１２０ｇに対して金属換算でＴｉ
が０．３０ｍｏｌ担持され、金属換算でＺｒが０．３０
ｍｏｌ担持されている。 （比較例１）チタン酸テトライソプロピル及びジルコニ
ウムテトラｎ−ブトキシドを用いなかったこと以外は実
施例１と同様にして、比較例１の触媒を調製した。得ら
れた触媒には、当然ながらＴｉとＺｒは担持されていな
い。 （比較例２，３）チタン酸テトライソプロピルとジルコ
ニウムテトラｎ−ブトキシドの一方のみを用いたこと以
外は実施例１と同様にして、比較例２及び比較例３の触
媒を調製した。比較例２の触媒には担体基材１Ｌに対し
てＴｉ（金属換算）が０．６０ｍｏｌ担持され、比較例
３の触媒には担体基材１Ｌに対してＺｒ（金属換算）が
０．６０ｍｏｌ担持されている。 （比較例４）活性アルミナ６００ｇとジルコニア粉末１
８５ｇ、チタニア粉末１２０ｇを混合し、実施例１と同
様にしてＰｔ担持粉末を調整した。To this Pt-supported powder, titania sol and zirconia sol were added, stirred and evaporated to dryness, followed by firing at 500 ° C. for 1 hour. After that, Ba was carried in the same manner as in Example 1 and a coat layer was similarly formed to obtain the catalyst of Example 7.
Ti and Zr are supported on alumina powder as a Ti-Zr composite oxide, and 120 g of alumina corresponds to Ti in terms of metal.
Is carried by 0.30 mol, and Zr is 0.30 in terms of metal.
mol supported. Comparative Example 1 A catalyst of Comparative Example 1 was prepared in the same manner as in Example 1 except that tetraisopropyl titanate and zirconium tetra n-butoxide were not used. Naturally, Ti and Zr were not supported on the obtained catalyst. (Comparative Examples 2 and 3) Catalysts of Comparative Examples 2 and 3 were prepared in the same manner as in Example 1 except that only one of tetraisopropyl titanate and zirconium tetra n-butoxide was used. The catalyst of Comparative Example 2 carries 0.60 mol of Ti (metal equivalent) on 1 L of the carrier substrate, and the catalyst of Comparative Example 3 carries 0.60 mol of Zr (metal equivalent) on 1 L of the carrier substrate. Has been done. (Comparative Example 4) 600 g of activated alumina and zirconia powder 1
85 g and 120 g of titania powder were mixed and a Pt-supported powder was prepared in the same manner as in Example 1.
【００２０】この粉末を用い、実施例１と同様にＢａを
担持した後、スラリー化し、ハニカム担体基材を用いて
コート層を形成して担体基材１Ｌ当りＰｔ２ｇ、Ｔｉ
０．３ｍｏｌ、Ｚｒ０．３ｍｏｌ、Ｂａ０．３ｍｏｌを
担持した触媒を得た。 （評価）上記のそれぞれの触媒を評価装置に配置し、入
りガス温度を２５０℃、３００℃及び３５０℃の４水準
とし、リッチ側の排ガスとリーン側の排ガスを２分毎に
繰り返して流す過渡域におけるＮＯX の浄化率を測定し
た。その結果を初期浄化率として表１に示す。Using this powder, after carrying Ba in the same manner as in Example 1, it was slurried to form a coat layer using a honeycomb carrier base material, and 2 g of Pt and Ti were added per 1 L of the carrier base material.
A catalyst supporting 0.3 mol, Zr 0.3 mol, and Ba 0.3 mol was obtained. (Evaluation) Each of the above catalysts is arranged in an evaluation device, the incoming gas temperature is set to four levels of 250 ° C., 300 ° C. and 350 ° C., and the rich side exhaust gas and the lean side exhaust gas are repeatedly passed every 2 minutes. The purification rate of NO X in the range was measured. The results are shown in Table 1 as the initial purification rate.
【００２１】また、それぞれの触媒に、入りガス温度５
５０℃の条件で、ＳＯ2 を１００ｐｐｍ含むリッチ側の
排ガスを４分流し次いでＳＯ2 を１００ｐｐｍ含むリー
ン側の排ガスを１分流すのを１サイクルとして、それを
６０サイクル行う耐久試験を施し、その後上記と同様の
条件にて過渡域におけるＮＯX の浄化率を測定した。そ
の結果を耐久後浄化率として表１に示す。In addition, the gas temperature of each catalyst is 5
Under the condition of 50 ° C., a rich side exhaust gas containing 100 ppm of SO 2 is allowed to flow for 4 minutes, and then a lean side exhaust gas containing 100 ppm of SO 2 is allowed to flow for 1 minute. The NO x purification rate in the transient region was measured under the same conditions as above. The results are shown in Table 1 as the post-durability purification rate.
【００２２】[0022]
【表１】 [Table 1]
【００２３】表１より、実施例の触媒は初期浄化率に比
べて耐久後浄化率の低下度合いが比較例よりも小さく、
実施例の触媒では耐久試験時における硫黄被毒の程度が
小さいことがわかる。そして、実施例と比較例との比較
より、ＴｉとＺｒを単独で担持しても硫黄被毒防止効果
が小さく、またＴｉとＺｒを単独酸化物として共存担持
しても硫黄被毒防止効果が小さいので、ＴｉとＺｒとが
複合酸化物として担持されて初めて硫黄被毒防止効果が
発現することが明らかである。As can be seen from Table 1, the catalysts of Examples have a smaller degree of reduction in the post-durability purification rate than the Comparative Example, compared to the initial purification rate.
It can be seen that the catalysts of Examples have a small degree of sulfur poisoning during the durability test. From the comparison between the example and the comparative example, the effect of preventing sulfur poisoning is small even when Ti and Zr are supported alone, and the effect of preventing sulfur poisoning is small even when Ti and Zr are co-supported as single oxides. Since it is small, it is clear that the effect of preventing sulfur poisoning is exhibited only when Ti and Zr are supported as a composite oxide.
【００２４】[0024]
【発明の効果】すなわち本発明の排ガス浄化用触媒によ
れば、ＮＯX 吸収材の硫黄被毒が防止されるので、耐久
後にも高いＮＯX 浄化性能を維持することができる。According to the exhaust gas purifying catalyst of the present invention, sulfur poisoning of the NO X absorbent is prevented, so that a high NO X purifying performance can be maintained even after endurance.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０１Ｄ 53/81 53/86 ＺＡＢ 53/94 Ｂ０１Ｊ 20/04 ＺＡＢ Ｃ Ｂ０１Ｄ 53/36 ＺＡＢ １０４ Ａ (72)発明者 三好 直人 愛知県豊田市トヨタ町１番地 トヨタ自動 車株式会社内 (72)発明者 木村 希夫 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 (72)発明者 川合 祐三 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 高橋 直樹 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 田中 寿幸 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─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI Technical display location B01D 53/81 53/86 ZAB 53/94 B01J 20/04 ZAB C B01D 53/36 ZAB 104 A ( 72) Inventor Naoto Miyoshi 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Norio Kimura 1 41, Yokochi, Nagakute Town, Aichi District, Aichi Prefecture Toyota Central Research Institute Co. 72) Inventor Yuzo Kawai No. 41, Nagachote, Nagakute-machi, Aichi-gun, Aichi Prefecture, 1st in Yokota Central Research Institute Co., Ltd. Company Toyota Central Research Institute (72) Inventor Toshiyuki Tanaka 1 of 41 Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Toyota Central Research Co., Ltd. Inside the laboratory
Claims (1)
物と、アルカリ金属，アルカリ土類金属及び希土類元素
から選ばれるＮＯX 吸収材と、触媒貴金属と、を担持し
てなることを特徴とする排ガス浄化用触媒。To 1. A on an alumina support, and a Ti-Zr composite oxide, and wherein the NO X absorbent is selected from an alkali metal, alkaline earth metal and rare earth elements, and catalytic noble metal, by comprising carrying Exhaust gas purification catalyst.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25697694A JP3378096B2 (en) | 1994-10-21 | 1994-10-21 | Exhaust gas purification catalyst |
| EP95116599A EP0707882A1 (en) | 1994-10-21 | 1995-10-20 | Catalyst for purifying exhaust gases |
| US08/551,918 US5804152A (en) | 1994-10-21 | 1995-10-23 | Method for purifying exhaust gases |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25697694A JP3378096B2 (en) | 1994-10-21 | 1994-10-21 | Exhaust gas purification catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08117602A true JPH08117602A (en) | 1996-05-14 |
| JP3378096B2 JP3378096B2 (en) | 2003-02-17 |
Family
ID=17299996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25697694A Expired - Lifetime JP3378096B2 (en) | 1994-10-21 | 1994-10-21 | Exhaust gas purification catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3378096B2 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08224469A (en) * | 1994-12-19 | 1996-09-03 | Toyota Motor Corp | Highly heat-resistant catalyst carrier, its production, highly heat-resistant catalyst and its production |
| JPH11169708A (en) * | 1997-12-15 | 1999-06-29 | Hitachi Ltd | Exhaust gas purification device for internal combustion engine |
| JP2000342966A (en) * | 1999-06-08 | 2000-12-12 | Toyota Motor Corp | Catalyst for purifying exhaust gas and method for purifying exhaust gas |
| JP2002361088A (en) * | 2001-05-01 | 2002-12-17 | Johnson Matthey Japan Inc | NOx ABSORPTION AND REDUCTION-TYPE CATALYST |
| JP2004535277A (en) * | 2001-04-13 | 2004-11-25 | エンゲルハード・コーポレーシヨン | SOx-resistant NOx trapping catalyst and method for producing and using the same |
| US7220702B2 (en) | 2001-02-19 | 2007-05-22 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification catalyst |
| WO2014135937A2 (en) | 2013-03-05 | 2014-09-12 | Toyota Jidosha Kabushiki Kaisha | Diesel exhaust gas oxidation catalyst, and method for purifying diesel exhaust gas by using same |
| US10906816B2 (en) | 2016-07-29 | 2021-02-02 | Sumitomo Chemical Company, Limited | Alumina and method for producing automotive catalyst using same |
-
1994
- 1994-10-21 JP JP25697694A patent/JP3378096B2/en not_active Expired - Lifetime
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08224469A (en) * | 1994-12-19 | 1996-09-03 | Toyota Motor Corp | Highly heat-resistant catalyst carrier, its production, highly heat-resistant catalyst and its production |
| JPH11169708A (en) * | 1997-12-15 | 1999-06-29 | Hitachi Ltd | Exhaust gas purification device for internal combustion engine |
| JP2000342966A (en) * | 1999-06-08 | 2000-12-12 | Toyota Motor Corp | Catalyst for purifying exhaust gas and method for purifying exhaust gas |
| US7220702B2 (en) | 2001-02-19 | 2007-05-22 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification catalyst |
| US7229947B2 (en) | 2001-02-19 | 2007-06-12 | Toyota Jidosha Kabushiki Kaisha | Catalyst for hydrogen generation and catalyst for purifying of exhaust gas |
| JP2004535277A (en) * | 2001-04-13 | 2004-11-25 | エンゲルハード・コーポレーシヨン | SOx-resistant NOx trapping catalyst and method for producing and using the same |
| JP2002361088A (en) * | 2001-05-01 | 2002-12-17 | Johnson Matthey Japan Inc | NOx ABSORPTION AND REDUCTION-TYPE CATALYST |
| WO2014135937A2 (en) | 2013-03-05 | 2014-09-12 | Toyota Jidosha Kabushiki Kaisha | Diesel exhaust gas oxidation catalyst, and method for purifying diesel exhaust gas by using same |
| US10906816B2 (en) | 2016-07-29 | 2021-02-02 | Sumitomo Chemical Company, Limited | Alumina and method for producing automotive catalyst using same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3378096B2 (en) | 2003-02-17 |
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