JPH05237384A - Catalyst for purifying exhaust gas - Google Patents

Catalyst for purifying exhaust gas

Info

Publication number
JPH05237384A
JPH05237384A JP4042920A JP4292092A JPH05237384A JP H05237384 A JPH05237384 A JP H05237384A JP 4042920 A JP4042920 A JP 4042920A JP 4292092 A JP4292092 A JP 4292092A JP H05237384 A JPH05237384 A JP H05237384A
Authority
JP
Japan
Prior art keywords
oxide
catalyst
palladium
rhodium
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
Application number
JP4042920A
Other languages
Japanese (ja)
Other versions
JP2755513B2 (en
Inventor
Eiichi Shiraishi
英市 白石
Hideyuki Baba
英幸 馬場
Kazuo Tsuchiya
一雄 土谷
Tomohisa Ohata
知久 大幡
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Shokubai Co Ltd
Original Assignee
Nippon Shokubai Co Ltd
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Filing date
Publication date
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Priority to JP4042920A priority Critical patent/JP2755513B2/en
Publication of JPH05237384A publication Critical patent/JPH05237384A/en
Application granted granted Critical
Publication of JP2755513B2 publication Critical patent/JP2755513B2/en
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Expired - Lifetime legal-status Critical Current

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  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Catalysts (AREA)

Abstract

PURPOSE:To provide a catalyst for simultaneously removing hydrocarbons(HC), carbon monoxide(CO) and nitrogen oxides(NOX) in exhaust gas from an internal combustion engine such as an automobile. CONSTITUTION:This catalyst is integrally coated with a catalytic active component which contains palladium and rhodium (a) or palladium, rhodium and platinum (b), and alkaline earth metal oxide, lanthanum oxide, cerium oxide, zirconium oxide, and refractory inorg. oxides.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は自動車等の内燃機関から
の排気ガス中に含まれる有害成分である一酸化炭素(C
O)、炭化水素(HC)及び窒素酸化物(NOx)を同
時に除去する排気ガス浄化用触媒に関するものである。
BACKGROUND OF THE INVENTION The present invention relates to carbon monoxide (C) which is a harmful component contained in exhaust gas from an internal combustion engine such as an automobile.
O), hydrocarbons (HC) and nitrogen oxides (NOx) at the same time.

【0002】[0002]

【従来の技術】内燃機関から排出される排気ガス中の有
害成分を除去する方法として、種々の排気ガス浄化用触
媒が提案されている。
2. Description of the Related Art Various exhaust gas purifying catalysts have been proposed as a method for removing harmful components in exhaust gas discharged from an internal combustion engine.

【0003】従来、パラジウム触媒は高い耐熱性を有し
ていることや、エンジン排気ガスの酸化雰囲気(いわゆ
るリーン;空気/燃料(A/F)が空気側大)における
CO、HCの高い浄化能を有することは一般に知られて
いる。しかし、エンジン排ガスが還元雰囲気(いわゆる
リッチ;(A/F)が燃料側大)の場合、NOx浄化能
が著しく低いことが挙げられ、パラジウムのみでは、三
元触媒として機能し難いことが知られている。そのため
に、一般的に高いNOx浄化能を有するロジウムを上記
パラジウムと組み合せて、CO、HC及びNOxを同時
に浄化する三元触媒として用いられている。一方、その
性能は白金・ロジウム系触媒にくらべ低く、かつ耐久性
能にも問題があることが一般に知られている。しかしパ
ラジウムは、白金・ロジウム系に比べ、著しく低コスト
であるため、安価なパラジウムを使用した触媒系でのC
O,HC及びNOxを同時に浄化できる触媒が望まれて
いる。
Conventionally, a palladium catalyst has a high heat resistance and a high purification ability of CO and HC in an oxidizing atmosphere of an engine exhaust gas (so-called lean; air / fuel (A / F) is large on the air side). It is generally known to have However, when the engine exhaust gas is in a reducing atmosphere (so-called rich; (A / F) is large on the fuel side), the NOx purification capacity is extremely low, and it is known that palladium alone is difficult to function as a three-way catalyst. ing. Therefore, in general, rhodium, which has a high NOx purification ability, is used in combination with the above palladium as a three-way catalyst for simultaneously purifying CO, HC and NOx. On the other hand, it is generally known that its performance is lower than that of platinum / rhodium-based catalysts and that it also has a problem in durability performance. However, palladium is significantly lower in cost than platinum / rhodium-based catalysts, so C in a catalyst system using inexpensive palladium
A catalyst capable of simultaneously purifying O, HC and NOx is desired.

【0004】[0004]

【発明が解決しようとする課題】本発明は、先に述べた
パラジウムの問題点である還元雰囲気におけるNOx浄
化能及び耐久性を改良することにより、高性能パラジウ
ム・ロジウム系触媒を開発し、さらに、白金・ロジウム
系触媒の白金の一部又は全部をパラジウムに替えること
による安価な触媒を提供することを目的とする。
DISCLOSURE OF THE INVENTION The present invention has developed a high-performance palladium-rhodium-based catalyst by improving the NOx purifying ability and durability in a reducing atmosphere, which is a problem of palladium described above. An object of the present invention is to provide an inexpensive catalyst by replacing part or all of platinum in a platinum / rhodium-based catalyst with palladium.

【0005】[0005]

【課題を解決するための手段】本発明者らは、この課題
を解決するために鋭意研究した結果、貴金属として、
(a)パラジウム及びロジウム、又は(b)パラジウ
ム、ロジウム及び白金、並びにアルカリ土類金属酸化
物、ランタン酸化物、セリウム酸化物、ジルコニウム酸
化物及び耐火性無機酸化物よりなる系で、従来のパラジ
ウム・ロジウム系に比べ、著しい性能向上を示し、さら
に、白金・ロジウム系三元触媒に比べても同等以上の性
能を有することを見出し本発明を完成するに至ったので
ある。
Means for Solving the Problems As a result of intensive studies to solve this problem, the present inventors
(A) Palladium and Rhodium, or (b) Palladium, Rhodium and Platinum, and a system comprising conventional alkaline earth metal oxides, lanthanum oxides, cerium oxides, zirconium oxides and refractory inorganic oxides. The present invention has been completed by discovering that the performance is remarkably improved as compared with the rhodium-based catalyst and that the platinum-rhodium-based three-way catalyst has the same or higher performance.

【0006】本発明におけるアルカリ土類金属酸化物の
添加効果は、パラジウムに直接作用することで、その電
荷状態を変化させることにより反応性を高め、リッチ雰
囲気でのNOx浄化能を飛躍的に向上させるものであ
る。
The effect of adding the alkaline earth metal oxide in the present invention is to directly react with palladium to change its charge state to enhance the reactivity and dramatically improve the NOx purification ability in a rich atmosphere. It is what makes them.

【0007】また、セリウム酸化物及びジルコニウム酸
化物を用いることにより、前記の効果はより向上するの
みならず、燃料ガス組成が化学量論比(燃料ガスを完全
燃焼させるのに必要な空気量)近傍でのCO、HC及び
NOx浄化能も向上することが示される。
Further, by using cerium oxide and zirconium oxide, not only the above effect is further improved but also the fuel gas composition has a stoichiometric ratio (the amount of air required to completely burn the fuel gas). It is also shown that CO, HC and NOx purifying ability in the vicinity is also improved.

【0008】さらに、ランタン酸化物を耐火性無機酸化
物、セリウム酸化物又はジルコニウム酸化物の少なくと
も一種に担持させることにより、前記の効果は飛躍的に
向上する。ランタン酸化物は一体構造体1リットル当た
り0.1〜50g被覆されていることが好ましく、0.
1g未満であるときは、添加効果が少なく、50gを越
える時は、添加量に見合う効果が少ない。
Further, by supporting lanthanum oxide on at least one of refractory inorganic oxide, cerium oxide and zirconium oxide, the above-mentioned effects are dramatically improved. The lanthanum oxide is preferably coated in an amount of 0.1 to 50 g per liter of the monolithic structure.
When it is less than 1 g, the effect of addition is small, and when it exceeds 50 g, the effect commensurate with the amount added is small.

【0009】本発明は内燃機関の排ガス中の一酸化炭
素、炭化水素及び窒素酸化物を同時に除去する触媒にお
いて、触媒活性物質が、貴金属として(a)パラジウム
及びロジウム、又は(b)パラジウム、ロジウム及び白
金のいずれかを含み、さらにアルカリ土類金属酸化物、
ランタン酸化物、セリウム酸化物、ジルコニウム酸化物
及び耐火性無機酸化物を含有してなる触媒活性物質を一
体構造体に被覆してなることを特徴とする排気ガス浄化
用触媒である。
The present invention is a catalyst for simultaneously removing carbon monoxide, hydrocarbons and nitrogen oxides in exhaust gas of an internal combustion engine, wherein the catalytically active substance is (a) palladium and rhodium or (b) palladium and rhodium as noble metals. And any one of platinum, further alkaline earth metal oxide,
An exhaust gas purifying catalyst, characterized in that an integrated structure is coated with a catalytically active substance containing a lanthanum oxide, a cerium oxide, a zirconium oxide and a refractory inorganic oxide.

【0010】本発明に係る貴金属の使用量は触媒の使用
条件によって異なるが、貴金属が(a)パラジウム及び
ロジウムである場合、触媒活性物質当たり、パラジウム
が0.1〜10重量%であり、ロジウムが0.01〜
2.0重量%であることが好ましい。貴金属が(b)パ
ラジウム、ロジウム及び白金である場合、触媒活性物質
当たり、パラジウムが0.1〜10重量%であり、ロジ
ウムが0.01〜2.0重量%、白金が0.1〜10重
量%であることが好ましい。
The amount of the noble metal used according to the present invention varies depending on the use conditions of the catalyst. When the noble metal is (a) palladium and rhodium, the amount of palladium is 0.1 to 10% by weight based on the catalytically active substance, and rhodium is used. Is 0.01-
It is preferably 2.0% by weight. When the noble metal is (b) palladium, rhodium and platinum, palladium is 0.1 to 10% by weight, rhodium is 0.01 to 2.0% by weight, and platinum is 0.1 to 10 with respect to the catalytically active substance. It is preferably in the weight%.

【0011】各貴金属の担持される位置は特に限定され
ないが、セリウム酸化物、ジルコニウム酸化物、ランタ
ン酸化物又は、耐火性無機酸化物上に、単独又はこれら
の酸化物にまたがって担持されることが好ましい。
The position on which each noble metal is supported is not particularly limited, but it should be supported on cerium oxide, zirconium oxide, lanthanum oxide or refractory inorganic oxide, either alone or straddling these oxides. Is preferred.

【0012】次にアルカリ土類金属酸化物としては、ベ
リリウム酸化物、マグネシウム酸化物、カルシウム酸化
物、ストロンチウム酸化物及びバリウム酸化物が挙げら
れるが、特に、カルシウム酸化物、ストロンチウム酸化
物及びバリウム酸化物からなる群より選ばれた少なくと
も一種が好ましい。また、アルカリ土類金属酸化物源と
しては、酸化物、有機塩又は無機塩のいずれでもよく、
特に限定されるものではない。
Next, examples of the alkaline earth metal oxides include beryllium oxide, magnesium oxide, calcium oxide, strontium oxide and barium oxide, and particularly calcium oxide, strontium oxide and barium oxide. At least one selected from the group consisting of things is preferable. The alkaline earth metal oxide source may be an oxide, an organic salt or an inorganic salt,
It is not particularly limited.

【0013】アルカリ土類金属酸化物の使用量は触媒1
リットル当り0.1〜50g、好ましくは0.5〜40
gである。アルカリ土類金属酸化物は、セリウム酸化
物、ジルコニウム酸化物若しくはそれらの複合物、固溶
体、ランタン酸化物又は耐火性無機酸化物のいずれに担
持されてもよく、この担持の調製方法は、特に限定され
ない。
The amount of alkaline earth metal oxide used is the amount of catalyst 1
0.1 to 50 g per liter, preferably 0.5 to 40
It is g. The alkaline earth metal oxide may be supported on any of cerium oxide, zirconium oxide or a composite thereof, a solid solution, lanthanum oxide or a refractory inorganic oxide, and the method for preparing this support is not particularly limited. Not done.

【0014】アルカリ土類金属酸化物とパラジウムの関
係は、それらの重量比(アルカリ土類金属酸化物/パラ
ジウム)で、1:100〜150:1、好ましくは、
1:100〜100:1である。1:100よりアルカ
リ土類金属酸化物の量が少なくなると、三元性能が悪く
なり、特に、NO浄化率が劣り、150:1よりアルカ
リ土類金属酸化物の量が多くなると添加効果は向上する
が、その他酸化物等の担持量、触媒の強度の関係によ
り、担持比率、担持量を制限される。
The relationship between the alkaline earth metal oxide and the palladium is 1: 100 to 150: 1, preferably by weight ratio (alkaline earth metal oxide / palladium).
It is 1: 100 to 100: 1. When the amount of the alkaline earth metal oxide is less than 1: 100, the ternary performance is poor, and in particular, the NO purification rate is poor, and when the amount of the alkaline earth metal oxide is more than 150: 1, the addition effect is improved. However, the loading ratio and loading amount are limited by the relationship between the loading amount of oxides and the strength of the catalyst.

【0015】セリウム酸化物としては、特に限定される
ものではないが、酸化物のまま、又は種々の水溶性の塩
等を焼成することによりセリウム酸化物として用いるこ
とができる。セリウム酸化物の使用量は、触媒1リット
ル当り10〜150gが好ましく、10g未満である場
合は、浄化能が低く、また150gを超える場合は、そ
れ以上加えても大きな効果はみられない。
The cerium oxide is not particularly limited, but it can be used as the cerium oxide as it is or by burning various water-soluble salts or the like. The amount of cerium oxide used is preferably 10 to 150 g per liter of the catalyst, and when it is less than 10 g, the purifying ability is low, and when it exceeds 150 g, even if it is added more than that, no great effect is observed.

【0016】ジルコニウム酸化物としては、特に限定さ
れるものではないが、酸化物のまま、又は種々の水溶性
の塩等を焼成することによりジルコニウム酸化物として
もちいることができる。ジルコニウム酸化物の使用量
は、触媒1リットル当り0.1〜50gが好ましく、
0.1未満である場合は、効果が少なく、50gを超え
る場合は、浄化性能が低下する。
The zirconium oxide is not particularly limited, but it can be used as the zirconium oxide as it is or by firing various water-soluble salts or the like. The amount of zirconium oxide used is preferably 0.1 to 50 g per liter of the catalyst,
If it is less than 0.1, the effect is small, and if it exceeds 50 g, the purification performance is deteriorated.

【0017】セリウム酸化物とジルコニウム酸化物は、
少なくとも一部が複合物又は、固溶体として存在してな
ることが好ましい。さらに好ましくは、このセリウム酸
化物とジルコニウム酸化物の比(酸化物換算重量比)
が、100:2〜100:60であり、より好ましく
は、100:4〜100:40である。この比が、10
0:2よりセリウム酸化物が多くなると、性能が低く、
100:60よりジルコニウム酸化物が多くなると、性
能が低くなる傾向となるものである。
Cerium oxide and zirconium oxide are
It is preferable that at least a part thereof is present as a composite or a solid solution. More preferably, the ratio of this cerium oxide and zirconium oxide (weight ratio in terms of oxide)
Is 100: 2 to 100: 60, and more preferably 100: 4 to 100: 40. This ratio is 10
When the amount of cerium oxide is more than 0: 2, the performance is low,
If the amount of zirconium oxide is more than 100: 60, the performance tends to be low.

【0018】セリウム酸化物とジルコニウム酸化物の複
合物又は、固溶体の調製方法を以下に示すが、これらの
酸化物の少なくとも一部が複合物又は、固溶体として存
在してなるものであれば、特に限定されることはない
が、上記の比の範囲内にあることが好ましい。
A method for preparing a composite of cerium oxide and zirconium oxide or a solid solution is shown below. If at least a part of these oxides exists as a composite or a solid solution, it is particularly preferable. Although not limited, it is preferably within the range of the above ratio.

【0019】(1)水に溶解性のあるセリウム塩とジル
コニウム塩の水溶液を乾燥、焼成する方法、(2)セリ
ウム酸化物とジルコニウム酸化物とを固相反応させる方
法、(3)セリウム酸化物に水溶性ジルコニウム塩の水
溶液を浸し乾燥、焼成する方法、(4)耐火性無機酸化
物に水に溶解性のあるセリウム塩とジルコニウム塩の水
溶液を含浸後、乾燥、焼成する方法、又は(5)一体構
造体に耐火性無機酸化物を被覆した後に水に溶解性のあ
るセリウム塩とジルコニウム塩の水溶液を乾燥、焼成す
る方法等、触媒の調製に応じて種々の方法を適宜用いる
ことができる。
(1) A method of drying and calcining an aqueous solution of cerium salt and zirconium salt which are soluble in water, (2) a method of solid-phase reaction of cerium oxide and zirconium oxide, (3) cerium oxide (4) A method of soaking an aqueous solution of a water-soluble zirconium salt in an aqueous solution and drying and firing, and (4) a method of impregnating a water-soluble aqueous solution of a cerium salt and a zirconium salt into a refractory inorganic oxide, followed by drying and firing. ) Various methods can be appropriately used depending on the preparation of the catalyst, such as a method of coating the monolithic structure with a refractory inorganic oxide and then drying and calcining an aqueous solution of water-soluble cerium salt and zirconium salt. ..

【0020】ランタン酸化物としては、特に限定される
ものではないが、酸化物、又は種々の水溶性塩等を耐火
性無機酸化物、セリウム酸化物、ジルコニウム酸化物に
単独に、又はこれらの酸化物にまたがって担持されるも
のである。
The lanthanum oxide is not particularly limited, but oxides, various water-soluble salts and the like may be used alone as refractory inorganic oxides, cerium oxides, zirconium oxides, or oxidation thereof. It is carried across objects.

【0021】ランタン酸化物の使用量は、一体構造体1
リットル当たり0.1から50gが好ましく、0.1g
未満である場合は効果が少なく、50gを越える場合
は、それ以上加えてもそれに見合う効果はみられない。
The amount of lanthanum oxide used is 1
0.1 to 50 g per liter is preferred, 0.1 g
If the amount is less than 50 g, the effect is small, and if the amount exceeds 50 g, even if more than 50 g is added, the corresponding effect is not observed.

【0022】耐火性無機酸化物としては、活性アルミ
ナ、シリカ、ジルコニア等の高表面積を有するものが挙
げられるが、特に活性アルミナが好ましい。
Examples of the refractory inorganic oxide include those having a high surface area such as activated alumina, silica and zirconia, and activated alumina is particularly preferable.

【0023】触媒を調製する方法としては、(1)上記
した触媒組成物を、ボールミル等を用いて水性スラリー
とし、一体構造体に被覆したのち、乾燥、必要により焼
成して完成触媒とする方法、(2)耐火性酸化物を予め
一体構造体に被覆し、次いで、水に溶解性のあるセリウ
ム塩、ジルコニウム塩の水溶液に該一体構造体を浸漬し
たのち、乾燥、焼成後、次いで同様の手順でランタン塩
を担持する方法等があるが、作業手順の便により適宜変
更し使用される。
As a method for preparing a catalyst, (1) a method in which the above-mentioned catalyst composition is made into an aqueous slurry by using a ball mill or the like, coated on an integral structure, dried and, if necessary, calcined to obtain a finished catalyst. (2) The monolithic structure is coated in advance with a refractory oxide, and then the monolithic structure is immersed in an aqueous solution of a cerium salt or zirconium salt that is soluble in water, dried, fired, and then the same. There is a method of supporting lanthanum salt in the procedure, etc., but it is appropriately changed and used depending on the convenience of the work procedure.

【0024】一体構造体1リットルに対する触媒組成物
は、50〜400g好ましくは、100〜350gであ
る。50g未満である場合は、浄化性能が低く、400
gを超える場合は、一体成形体に触媒組成物を被覆した
場合、触媒組成物の被覆量が多くなり、触媒の背圧が上
昇し好ましくないものである。
The catalyst composition per liter of the monolithic structure is 50 to 400 g, preferably 100 to 350 g. If the amount is less than 50 g, the purification performance is low and 400
When it exceeds g, when the catalyst composition is coated on the integrally molded body, the coating amount of the catalyst composition increases, and the back pressure of the catalyst increases, which is not preferable.

【0025】[0025]

【実施例】以下に実施例により具体的に説明するが、本
発明の趣旨に反しない限り、これらの実施例に限定され
るものでない。
EXAMPLES The present invention will be specifically described below with reference to examples, but the invention is not limited to these examples unless it goes against the gist of the present invention.

【0026】(実施例1)市販のセリウム酸化物(比表
面積149m2/g)にオキシ硝酸ジルコニル水溶液を、
それぞれCeO2/ZrO2が100/10(CeO2
ZrO2が100g)となる比で混合し、乾燥後500
℃×1時間にて焼成した粉体100g(CeO2・Zr
2)を得た。次にパラジウムを1.667g含有する
硝酸パラジウム水溶液とロジウムを0.333g含有す
る硝酸ロジウム水溶液及びランタン酸化物として、20
gとなる酢酸ランタン水溶液を混合した溶液に、活性ア
ルミナ(γ−Al23、比表面積155m2/g)180
gを含浸し乾燥後、500℃×1時間にて焼成して粉体
200gを得た。
Example 1 Commercially available cerium oxide (specific surface area 149 m 2 / g) was treated with an aqueous zirconyl oxynitrate solution.
CeO 2 / ZrO 2 is 100/10 (CeO 2 +
ZrO 2 is mixed at a ratio of 100 g), dried and then 500
100 g of powder calcined at ℃ × 1 hour (CeO 2 · Zr
O 2 ) was obtained. Then, as a palladium nitrate aqueous solution containing 1.667 g of palladium, a rhodium nitrate aqueous solution containing 0.333 g of rhodium and a lanthanum oxide, 20
180 g of activated alumina (γ-Al 2 O 3 , specific surface area 155 m 2 / g) was added to a solution obtained by mixing an aqueous solution of lanthanum acetate to be g.
After impregnating with g and drying, 200 g of powder was obtained by firing at 500 ° C. for 1 hour.

【0027】上記の得られた粉体と酢酸バリウム16.
7gをボールミルで湿式粉砕することにより水性スラリ
ーを調製した。断面積1インチ平方当り400個のセル
を有するコージェライト製モノリス担体(内径33mm×
長さ76mmL)を上記スラリーに浸漬し取り出した後セ
ル内の過剰スラリーを圧縮空気で吹き飛ばした後、乾燥
し必要により焼成し完成触媒を得た。
The powder obtained above and barium acetate 16.
An aqueous slurry was prepared by wet grinding 7 g with a ball mill. Cordierite monolith carrier with 400 cells per square inch cross section (inner diameter 33 mm x
A length of 76 mmL) was dipped in the above slurry, taken out, and the excess slurry in the cell was blown off with compressed air, followed by drying and firing if necessary to obtain a finished catalyst.

【0028】(実施例2)実施例1で用いたセリウム酸
化物にオキシ硝酸ジルコニル水溶液をCeO2/ZrO2
の比で10/1(CeO2とZrO2の合計が100
g)、及びランタン酸化物として20g含有する酢酸ラ
ンタン水溶液を混合し、乾燥後、500℃で1時間乾燥
して粉体120gを得た。次に、パラジウムを1.66
7g含有する硝酸パラジウム水溶液とロジウムを0.3
33g含有する硝酸ロジウム水溶液を混合した溶液に実
施例1で用いたものと同じ活性アルミナ180gを含浸
し乾燥後、500℃×1時間にて焼成して粉体180g
を得た。上記の得られた粉体と酢酸バリウム16.7g
をボールミルにて湿式粉砕し、スラリーを得、実施例1
と同様にして完成触媒を得た。
Example 2 The cerium oxide used in Example 1 was mixed with an aqueous solution of zirconyl oxynitrate to CeO 2 / ZrO 2.
Ratio of 10/1 (the total of CeO 2 and ZrO 2 is 100
g) and lanthanum acetate aqueous solution containing 20 g of lanthanum oxide were mixed, dried and then dried at 500 ° C. for 1 hour to obtain 120 g of powder. Then 1.66 of palladium
Palladium nitrate aqueous solution containing 7 g and rhodium 0.3
180 g of the same activated alumina as used in Example 1 was impregnated into a solution containing 33 g of an aqueous rhodium nitrate solution, dried, and then fired at 500 ° C. for 1 hour to give 180 g of powder.
Got 16.7 g of the above-obtained powder and barium acetate
Was pulverized with a ball mill to obtain a slurry.
A completed catalyst was obtained in the same manner as in.

【0029】(実施例3)実施例1で得られるCeO2
・ZrO2の粉体100g及び実施例2で得られるパラ
ジウム、ロジウム担持アルミナ180gを混合した粉体
に、ランタン酸化物として20g含有する酢酸ランタン
水溶液を加え乾燥後500℃×1時間焼成して得た粉体
300g及び酢酸バリウム16.7gをボールミルにて
湿式粉砕し、スラリーを得、実施例1と同様にして完成
触媒を得た。
Example 3 CeO 2 obtained in Example 1
Obtained by adding 100 g of ZrO 2 powder and 180 g of palladium- and rhodium-supported alumina obtained in Example 2 to a powder of lanthanum acetate aqueous solution containing 20 g of lanthanum oxide, and drying and firing at 500 ° C. for 1 hour. 300 g of the powder and 16.7 g of barium acetate were wet pulverized with a ball mill to obtain a slurry, and a completed catalyst was obtained in the same manner as in Example 1.

【0030】(実施例4)実施例1で得られるCeO2
・ZrO2粉体100g、及び実施例2で得られるパラ
ジウム、ロジウム担持アルミナ180gとランタン酸化
物として20g含有する酢酸ランタン、及び酢酸バリウ
ム16.7gをボールミルにて湿式粉砕しスラリーを
得、実施例1と同様にして完成触媒を得た。
Example 4 CeO 2 obtained in Example 1
100 g of ZrO 2 powder, palladium obtained in Example 2, 180 g of rhodium-supported alumina, 20 g of lanthanum acetate as lanthanum oxide, and 16.7 g of barium acetate were wet-milled with a ball mill to obtain a slurry. A completed catalyst was obtained in the same manner as in 1.

【0031】(実施例5)実施例1において、ランタン
酸化物20gを1gに変えた以外は実施例1と同様にし
て完成触媒を得た。
Example 5 A completed catalyst was obtained in the same manner as in Example 1 except that 20 g of lanthanum oxide was changed to 1 g.

【0032】(実施例6)実施例1において、ランタン
酸化物20gを90gに変えた以外は実施例1と同様に
して完成触媒を得た。
Example 6 A completed catalyst was obtained in the same manner as in Example 1 except that 20 g of lanthanum oxide was changed to 90 g.

【0033】(実施例7)実施例1において、酢酸バリ
ウム16.7gを133.6gに変えた以外は実施例1
と同様にして完成触媒を得た。
Example 7 Example 1 was repeated except that 16.7 g of barium acetate was changed to 133.6 g.
A completed catalyst was obtained in the same manner as in.

【0034】(実施例8)実施例1において、酢酸バリ
ウム16.7gを0.83gに変えた以外は実施例1と
同様にして完成触媒を得た。
(Example 8) A completed catalyst was obtained in the same manner as in Example 1 except that 16.7 g of barium acetate was changed to 0.83 g.

【0035】(実施例9)実施例1において、酢酸バリ
ウムを酢酸カルシウム28.2gに変えた以外は実施例
1と同様にして完成触媒を得た。
(Example 9) A completed catalyst was obtained in the same manner as in Example 1 except that barium acetate was changed to 28.2 g of calcium acetate.

【0036】(実施例10)実施例1において、酢酸バ
リウムを酢酸ストロンチウム19.8gに変えた以外
は、実施例1と同様にして完成触媒を得た。
(Example 10) A completed catalyst was obtained in the same manner as in Example 1 except that barium acetate was changed to strontium acetate 19.8 g.

【0037】(実施例11)実施例1において、CeO
2/ZrO2の比を10/1(CeO2とZrO2の合計が
30g)に変えた以外は、実施例1と同様にして完成触
媒を得た。
(Embodiment 11) In Embodiment 1, CeO
A completed catalyst was obtained in the same manner as in Example 1 except that the ratio of 2 / ZrO 2 was changed to 10/1 (the total of CeO 2 and ZrO 2 was 30 g).

【0038】(実施例12)実施例1において、CeO
2/ZrO2の比を10/1(CeO2とZrO2の合計が
200g)に変えた以外は、実施例1と同様にして完成
触媒を得た。
(Embodiment 12) In Embodiment 1, CeO
A completed catalyst was obtained in the same manner as in Example 1 except that the ratio of 2 / ZrO 2 was changed to 10/1 (the total of CeO 2 and ZrO 2 was 200 g).

【0039】(実施例13)実施例1において、CeO
2/ZrO2の比を10/1(CeO2とZrO2の合計が
280g)に変えた以外は、実施例1と同様にして完成
触媒を得た。
(Example 13) In Example 1, CeO
A completed catalyst was obtained in the same manner as in Example 1 except that the ratio of 2 / ZrO 2 was changed to 10/1 (the total of CeO 2 and ZrO 2 was 280 g).

【0040】(実施例14)実施例1において、CeO
2/ZrO2の比を10/3(CeO2とZrO2の合計が
100g)に変えた以外は、実施例1と同様にして完成
触媒を得た。
Example 14 In Example 1, CeO was used.
A completed catalyst was obtained in the same manner as in Example 1 except that the ratio of 2 / ZrO 2 was changed to 10/3 (the total amount of CeO 2 and ZrO 2 was 100 g).

【0041】(実施例15)実施例1において、CeO
2/ZrO2の比を25/1(CeO2とZrO2の合計が
100g)に変えた以外は、実施例1と同様にして完成
触媒を得た。
Example 15 In Example 1, CeO was used.
A completed catalyst was obtained in the same manner as in Example 1 except that the ratio of 2 / ZrO 2 was changed to 25/1 (total of CeO 2 and ZrO 2 was 100 g).

【0042】(実施例16)実施例1において、酢酸バ
リウムを酢酸マグネシウム35.3gに変えた以外は、
実施例1と同様にして完成触媒を得た。
(Example 16) In Example 16, except that barium acetate was changed to 35.3 g of magnesium acetate,
A completed catalyst was obtained in the same manner as in Example 1.

【0043】(実施例17)実施例2において、パラジ
ウム・ロジウム含有粉体をパラジウムを0.833g含
有する硝酸パラジウム水溶液と白金を0.833g含有
するジニトロジアミン白金水溶液及びロジウムを0.3
33g含有する硝酸ロジウム水溶液を混合した溶液に活
性アルミナ(γ・Al23、比表面積155m2/g)1
80gを含浸担持した粉体に変えた以外は実施例1と同
様にして完成触媒を得た。
(Example 17) In Example 2, the palladium / rhodium-containing powder was added to an aqueous palladium nitrate solution containing 0.833 g of palladium, an aqueous dinitrodiamine platinum solution containing 0.833 g of platinum, and 0.3 g of rhodium.
Activated alumina (γ · Al 2 O 3 , specific surface area 155 m 2 / g) was added to a solution containing 33 g of rhodium nitrate aqueous solution.
A finished catalyst was obtained in the same manner as in Example 1, except that 80 g of the powder was impregnated and supported.

【0044】(比較例1)実施例1において、酢酸バリ
ウムを除いた以外は実施例1と同様にして完成触媒を得
た。
Comparative Example 1 A completed catalyst was obtained in the same manner as in Example 1 except that barium acetate was omitted.

【0045】(比較例2)実施例1において、オキシ硝
酸ジルコニルを除いた以外は、実施例1と同様にして完
成触媒を得た。
Comparative Example 2 A finished catalyst was obtained in the same manner as in Example 1 except that zirconyl oxynitrate was omitted.

【0046】(比較例3)実施例1において、オキシ硝
酸ジルコニル及び酢酸バリウムを除いた以外は実施例1
と同様にして完成触媒を得た。
(Comparative Example 3) Example 1 is the same as Example 1 except that zirconyl oxynitrate and barium acetate are removed.
A completed catalyst was obtained in the same manner as in.

【0047】(比較例4)実施例1において、ランタン
酸化物を除いた以外は、実施例1と同様にして完成触媒
を得た。
(Comparative Example 4) A finished catalyst was obtained in the same manner as in Example 1 except that the lanthanum oxide was removed.

【0048】(比較例5)白金を1.667g含有する
ジニトロジアミン白金水溶液及びロジウムを0.333
g含有する硝酸ロジウム水溶液を混合した溶液に活性ア
ルミナ(γ・Al23、比表面積155m2/g)200
gを含浸担持した粉体と市販のセリウム酸化物(比表面
積149m2/g)100gをボールミルにて湿式粉砕し
て水性スラリーを得、実施例1と同様にして完成触媒を
得た。
Comparative Example 5 A dinitrodiamine platinum aqueous solution containing 1.667 g of platinum and 0.333 of rhodium.
Activated alumina (γ · Al 2 O 3 , specific surface area 155 m 2 / g) 200 was added to a solution containing a rhodium nitrate aqueous solution containing g.
A powder impregnated with g and 100 g of a commercially available cerium oxide (specific surface area 149 m 2 / g) were wet pulverized with a ball mill to obtain an aqueous slurry, and a completed catalyst was obtained in the same manner as in Example 1.

【0049】(比較例6)比較例5において、白金を
1.667g含有するジニトロジアミン白金水溶液をパ
ラジウム1.667g含有する硝酸パラジウム水溶液に
変えた以外は比較例5と同様にして完成触媒を得た。
Comparative Example 6 A completed catalyst was obtained in the same manner as in Comparative Example 5 except that the aqueous dinitrodiamine platinum solution containing 1.667 g of platinum was replaced with the aqueous palladium nitrate solution containing 1.667 g of palladium. It was

【0050】このようにして得られた実施例と比較例の
触媒の1リットル当りの各触媒成分の担持量を表1に示
した。
Table 1 shows the supported amounts of the respective catalyst components per liter of the catalysts of Examples and Comparative Examples thus obtained.

【0051】(実施例18)次に、実施例1から実施例
17までの触媒と、比較例1から6の触媒のエンジン耐
久走行後の触媒活性を調べた。
(Example 18) Next, the catalyst activities of the catalysts of Examples 1 to 17 and the catalysts of Comparative Examples 1 to 6 were examined after the running of the engine for a long time.

【0052】市販の電子制御方式のエンジン(8気筒4
400cc)を使用し、各触媒を充填したマルチコンバー
タをエンジンの排気系に連設して耐久テストを行なっ
た。エンジンは、定常運転60秒、減速6秒(減速時に
燃料がカットされて、触媒は、高温酸化雰囲気の厳しい
条件にさらされる。)というモード運転で運転し触媒入
口ガス温度が定常運転時900℃となる条件で50時間
触媒をエージングした。
Commercially available electronically controlled engine (8 cylinders 4
400cc) was used, and a multi-converter filled with each catalyst was connected to the exhaust system of the engine for a durability test. The engine operates in a mode operation of 60 seconds of steady operation and 6 seconds of deceleration (fuel is cut during deceleration, and the catalyst is exposed to severe conditions of high temperature oxidizing atmosphere), and the gas temperature at the catalyst inlet is 900 ° C during steady operation. The catalyst was aged for 50 hours under the following conditions.

【0053】エージング後の触媒性能の評価は、市販の
電子制御方式のエンジン(4気筒1800cc)を使用
し、各触媒を充填したマルチコンバータを、エンジンの
排気系に連設して行なった。触媒の三元性能は触媒入口
ガス温度400℃、空間速度90,000hr~1の条件
で評価した。この際、外部発振器より1Hzサイン波型
シグナルをエンジンのコントロールユニットに導入し
て、空燃比(A/F)を±1.0A/F、1Hzで振動
させながら平均空燃比を連続的に変化させ、この時の触
媒入口及び出口ガス組成を同時に分析して、平均空燃比
がA/Fが15.1から14.1までCO,HC及びN
Oの浄化率を求めた。
The catalyst performance after aging was evaluated by using a commercially available electronically controlled engine (four-cylinder 1800 cc) and connecting a multi-converter filled with each catalyst to the exhaust system of the engine. The three-way performance of the catalyst was evaluated under the conditions of a catalyst inlet gas temperature of 400 ° C. and a space velocity of 90,000 hr- 1 . At this time, a 1 Hz sine wave type signal was introduced into the engine control unit from an external oscillator to continuously change the average air-fuel ratio while oscillating the air-fuel ratio (A / F) at ± 1.0 A / F and 1 Hz. At the same time, the catalyst inlet and outlet gas compositions were analyzed at the same time, and the average air-fuel ratio from A / F 15.1 to 14.1 CO, HC and N
The purification rate of O was determined.

【0054】上記のようにして求めたCO,HC及びN
Oの浄化率対入口空燃比をグラフにプロットして、三元
特性曲線を作成し、CO,NO浄化率曲線の交点(クロ
スオーバーポイントと呼ぶ)の浄化率と、その交点のA
/F値におけるHC浄化率さらに、A/Fが14.2
(エンジン排気ガスがリッチ)でのNOの浄化能を表2
に示した。
CO, HC and N determined as described above
The purification rate of O versus the inlet air-fuel ratio is plotted in a graph to create a ternary characteristic curve, and the purification rate at the intersection (called a crossover point) of the CO and NO purification rates and the intersection A
HC purification rate at / F value Further, A / F is 14.2
Table 2 shows the NO purifying ability when the engine exhaust gas is rich.
It was shown to.

【0055】表2より、本発明に開示させる触媒は、C
O,HCおよびNOxの三成分を同時に高性能に除去で
きることがわかる。
From Table 2, the catalyst disclosed in the present invention is C
It can be seen that the three components of O, HC and NOx can be simultaneously removed with high performance.

【0056】また、触媒の低温での浄化性能は、空燃比
を±0.5A/F(1Hz)の条件で振動させながら、
平均空燃比をA/Fに14.6に固定してエンジンを運
転し、エンジン排気系の触媒コンバータの前に熱交換器
を取り付けて、触媒入口ガス温度を200℃〜500℃
まで連続的に変化させ、触媒入口及び出口ガス組成を分
析して、CO,HC及びNOの浄化率を求めることによ
り評価した。上記の様にして求めた、CO,HC及びN
Oの浄化率50%での温度(ライトオフ温度)を測定し
て表2に示した。
Further, the purification performance of the catalyst at low temperature is as follows while vibrating the air-fuel ratio at ± 0.5 A / F (1 Hz).
The engine is operated with the average air-fuel ratio fixed to A / F of 14.6, a heat exchanger is installed in front of the catalytic converter of the engine exhaust system, and the catalyst inlet gas temperature is 200 ° C to 500 ° C.
Was continuously changed, the catalyst inlet and outlet gas compositions were analyzed, and the purification rates of CO, HC and NO were obtained and evaluated. CO, HC and N determined as above
The temperature (light-off temperature) at a purification rate of O of 50% was measured and is shown in Table 2.

【0057】本発明に開示された触媒は著しく低温で、
HC,CO及びNOの三成分を同時除去でき、Pdの問
題点を克服した高性能Pd/Rh触媒であることがわか
る。
The catalysts disclosed in the present invention are
It can be seen that it is a high-performance Pd / Rh catalyst capable of simultaneously removing three components of HC, CO and NO and overcoming the problem of Pd.

【0058】[0058]

【表1】 [Table 1]

【0059】[0059]

【表2】 [Table 2]

───────────────────────────────────────────────────── フロントページの続き (72)発明者 大幡 知久 兵庫県姫路市網干区興浜字西沖992番地の 1 株式会社日本触媒触媒研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohisa Ohata 1 992 Nishikioki, Kamahama, Aboshi-ku, Himeji-shi, Hyogo 1

Claims (4)

【特許請求の範囲】[Claims] 【請求項1】 内燃機関の排気ガス中の一酸化炭素、炭
化水素及び窒素酸化物を同時に除去する触媒において、 貴金属として、(a)パラジウム及びロジウム、又は
(b)パラジウム、ロジウム及び白金、 並びにアルカリ土類金属酸化物、ランタン酸化物、セリ
ウム酸化物、ジルコニウム酸化物及び耐火性無機酸化物
を含有する触媒活性成分を一体構造体に被覆してなるこ
とを特徴とする排気ガス浄化用触媒。
1. A catalyst for simultaneously removing carbon monoxide, hydrocarbons and nitrogen oxides in exhaust gas of an internal combustion engine, wherein (a) palladium and rhodium, or (b) palladium, rhodium and platinum, and An exhaust gas purifying catalyst, characterized in that an integral structure is coated with a catalytically active component containing an alkaline earth metal oxide, a lanthanum oxide, a cerium oxide, a zirconium oxide and a refractory inorganic oxide.
【請求項2】 セリウム酸化物とジルコニウム酸化物と
は、少なくとも一部が複合物又は固溶体として存在して
なる請求項1記載の触媒。
2. The catalyst according to claim 1, wherein at least a part of the cerium oxide and the zirconium oxide is present as a composite or solid solution.
【請求項3】 セリウム酸化物とジルコニウム酸化物の
比(酸化物換算重量比)が、100:2〜100:60
である請求項1又は2記載の触媒。
3. The ratio of cerium oxide to zirconium oxide (weight ratio in terms of oxide) is 100: 2 to 100: 60.
The catalyst according to claim 1 or 2, which is
【請求項4】 ランタン酸化物は、耐火性無機酸化物、
セリウム酸化物、及びジルコニウム酸化物のうち少なく
とも一種に担持されてなる請求項1記載の触媒。
4. The lanthanum oxide is a refractory inorganic oxide,
The catalyst according to claim 1, which is supported on at least one of cerium oxide and zirconium oxide.
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Cited By (6)

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EP0721796A1 (en) 1995-01-11 1996-07-17 Institut Français du Pétrole Catalyst for the selective reduction of nitrogen oxides in a oxidising atmosphere, process for preparation and utilisation
JP2000084405A (en) * 1998-08-24 2000-03-28 Degussa Huels Ag Nitrogen oxides-accumulating material and nitrogen oxides-accumulating catalyst to be prepared therefrom
US6500392B2 (en) 1996-12-20 2002-12-31 Ngk Insulators, Ltd. Catalyst for exhaust gas purification and system for exhaust gas purification
JP2012016681A (en) * 2010-07-09 2012-01-26 Ict:Kk Catalyst for purifying exhaust gas and method of manufacturing the same, as well as exhaust gas purifying method
CN105636673A (en) * 2013-10-22 2016-06-01 优美科股份公司及两合公司 Catalyst for the oxidation of CO and HC at low temperatures
JP2021507804A (en) * 2017-09-26 2021-02-25 ジョンソン、マッセイ、パブリック、リミテッド、カンパニーJohnson Matthey Public Limited Company Exhaust gas purification catalyst

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JPS6411643A (en) * 1987-07-06 1989-01-17 Toyota Central Res & Dev Catalyst for exhaust purification

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JPS6411643A (en) * 1987-07-06 1989-01-17 Toyota Central Res & Dev Catalyst for exhaust purification

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0721796A1 (en) 1995-01-11 1996-07-17 Institut Français du Pétrole Catalyst for the selective reduction of nitrogen oxides in a oxidising atmosphere, process for preparation and utilisation
US6500392B2 (en) 1996-12-20 2002-12-31 Ngk Insulators, Ltd. Catalyst for exhaust gas purification and system for exhaust gas purification
JP2000084405A (en) * 1998-08-24 2000-03-28 Degussa Huels Ag Nitrogen oxides-accumulating material and nitrogen oxides-accumulating catalyst to be prepared therefrom
JP2012016681A (en) * 2010-07-09 2012-01-26 Ict:Kk Catalyst for purifying exhaust gas and method of manufacturing the same, as well as exhaust gas purifying method
CN105636673A (en) * 2013-10-22 2016-06-01 优美科股份公司及两合公司 Catalyst for the oxidation of CO and HC at low temperatures
JP2021507804A (en) * 2017-09-26 2021-02-25 ジョンソン、マッセイ、パブリック、リミテッド、カンパニーJohnson Matthey Public Limited Company Exhaust gas purification catalyst

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