JP2578219B2 - Method for producing exhaust gas purifying catalyst - Google Patents
Method for producing exhaust gas purifying catalystInfo
- Publication number
- JP2578219B2 JP2578219B2 JP1269202A JP26920289A JP2578219B2 JP 2578219 B2 JP2578219 B2 JP 2578219B2 JP 1269202 A JP1269202 A JP 1269202A JP 26920289 A JP26920289 A JP 26920289A JP 2578219 B2 JP2578219 B2 JP 2578219B2
- Authority
- JP
- Japan
- Prior art keywords
- zirconium
- cerium
- catalyst
- exhaust gas
- oxide powder
- 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.)
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Description
【発明の詳細な説明】 （産業上の利用分野） 自動車等の内燃機関から排出される排ガス中の有害成
分である炭化水素（HC）、一酸化炭素（CO）、窒素酸化
物（NOx）を効率良く浄化する排ガス浄化用触媒の製造
方法に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) Hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxide (NOx), which are harmful components in exhaust gas emitted from internal combustion engines such as automobiles, are analyzed. The present invention relates to a method for producing an exhaust gas purifying catalyst that efficiently purifies the exhaust gas.
（従来の技術） 従来、内燃機関から排出される排ガス中のHC,CO,NOx
を浄化する排ガス浄化用触媒の製造方法は種々提案され
ている。(Prior art) Conventionally, HC, CO, NOx in exhaust gas discharged from an internal combustion engine
Various methods for producing an exhaust gas purifying catalyst for purifying methane have been proposed.
なかでも貴金属の活性成分とする排ガス浄化用触媒に
セリウム、ジルコニウムを適当量添加すると触媒性能が
向上することから、例えば、特公昭62−14338号、特開
昭61−157347号、特開昭63−116741号、特開昭63−1167
42号、特開平１−123636号公報に開示されているよう
に、触媒を製造する過程において、活性アルミナ、ある
いは活性アルミナ層を形成させた後のモノリス担体にセ
リウムおよびジルコニウムを硝酸塩水溶液等により含浸
担持させる工程を含む方法や、セリウム、ジルコニウム
それぞれの酸化物または炭酸塩粉末を活性アルミナ等と
混合、スラリー化しモノリス担体に塗布する工程を含む
方法が提案されている。Among them, the addition of an appropriate amount of cerium or zirconium to an exhaust gas purifying catalyst containing noble metal as an active component improves the catalytic performance. For example, JP-B-62-14338, JP-A-61-157347, and JP-A-63-157347 No.-116741, JP-A-63-1167
No. 42, as disclosed in JP-A-1-123636, in the process of producing the catalyst, activated alumina, or impregnated cerium and zirconium with a nitrate aqueous solution or the like on the monolith carrier after forming the active alumina layer. There has been proposed a method including a step of supporting, or a method including a step of mixing oxide or carbonate powder of cerium and zirconium with activated alumina, forming a slurry, and applying the slurry to a monolithic carrier.
（発明が解決しようとする課題） しかしながら、このような従来の排ガス浄化用触媒の
製造方法において、セリウムおよびジルコニウムを触媒
へ添加するにあって、 １） 硝酸塩等により含浸添加する方法ではセリウム、
ジルコニウムはアルミナの細孔あるいは触媒コート層の
マクロポアに担持されるため、添加量が多くなるとこれ
らの孔構造を閉塞し充分な触媒性能の向上効果が得られ
ない。(Problems to be Solved by the Invention) However, in such a conventional method for producing a catalyst for purifying exhaust gas, when cerium and zirconium are added to the catalyst, 1) cerium or zirconium is impregnated with nitrate or the like.
Since zirconium is supported on the pores of alumina or the macropores of the catalyst coat layer, if the amount of zirconium added is too large, these pore structures are closed, and a sufficient effect of improving the catalyst performance cannot be obtained.
２） セリウム、ジルコニウムそれぞれの酸化物または
炭酸塩粉末を活性アルミナ等と混合、スラリー化しモノ
リス担体に塗布する方法では、熱処理工程後に生成する
セリアとジルコニアの相互作用が小さく充分な助触媒作
用が得られない。2) In the method of mixing oxide or carbonate powders of cerium and zirconium with activated alumina and applying the slurry to a monolithic carrier, the interaction between ceria and zirconia generated after the heat treatment step is small and sufficient co-catalyst action is obtained. I can't.
等の問題点があった。And so on.
（課題を解決するための手段） 発明者は従来経験的に知られていた、セリウムとジル
コニウムの両方を添加することによる触媒の性能向上効
果が主に両方の酸化物の相互作用による酸素（O2）スト
レージ能の向上によること、 さらに、硝酸塩などの溶液を用い活性アルミナあるい
はアルミナコート層に助触媒成分を含浸担持する方法は
アルミナ等の細孔構造を維持するためには、一般にその
添加量を制限せざるを得ないことに鑑み、 従来のセリウム、ジルコニウムの添加方法に代わる方
法として、以下に述べる新規な触媒製造方法を見出すに
至った。(Means for Solving the Problems) The inventor of the present invention has been known from experience that the effect of adding both cerium and zirconium on the performance of the catalyst is mainly due to the oxygen (O 2 ) The method of impregnating the active alumina or alumina coat layer with a cocatalyst component using a solution such as a nitrate is necessary to improve the storage capacity. In view of the need to limit the amount of cerium and zirconium, a new method for producing a catalyst described below has been found as an alternative to the conventional method of adding cerium and zirconium.
即ち、本発明の触媒製造方法の特徴は、少くともセリ
ウムとジルコニウムのイオンを含む水溶液から沈澱生成
反応を用いて製造されたセリウムとジルコニウムを含む
酸化物粉末と、貴金属を含むかまたは含まないアルミナ
粉末とを用いて水性スラリーを調整し、モノリス担体に
塗布する工程を有することにある。That is, a feature of the catalyst production method of the present invention is that an oxide powder containing cerium and zirconium produced by a precipitation reaction from an aqueous solution containing at least ions of cerium and zirconium, and an alumina powder containing or not containing a noble metal. Another object of the present invention is to provide a step of preparing an aqueous slurry using powder and applying the slurry to a monolithic carrier.
本発明で用いるセリウム（Ce）とジルコニウム（Zr）
を含む酸化物粉末は、例えば、硝酸セリウムと硝酸ジル
コニルの混合水溶液等Ce、Zr両イオンを含む酸性溶液
に、アンモニア、尿素などを添加し、必要に応じて加
熱、加圧し、アルカリ性側にて水酸化物等の沈澱を生成
させ、得られた沈澱物を乾燥、焼成することによって製
造することができる。Cerium (Ce) and zirconium (Zr) used in the present invention
Oxide powder containing, for example, a mixed aqueous solution of cerium nitrate and zirconyl nitrate such as Ce, Zr to an acidic solution containing both ions, ammonia, urea, etc., if necessary, heated and pressurized, if necessary, on the alkaline side It can be produced by forming a precipitate such as a hydroxide and drying and calcining the obtained precipitate.
この酸化物粉末は、その含有する金属種としてセリウ
ム及びジルコニウムのみからなるもので充分な触媒性能
改良効果が得られるが、セリウム源としてセリウムを主
成分とし、他の希土類元素（例えばランタン、ネオジミ
ウム、プラセオジミウム、イットリウム）をも同時に含
む低純度のセリウム塩を用いてもよい。This oxide powder can provide a sufficient effect of improving the catalytic performance by using only cerium and zirconium as the metal species contained therein. However, cerium as a main component of cerium source and other rare earth elements (for example, lanthanum, neodymium, A low-purity cerium salt which also contains praseodymium and yttrium) may be used.
上記酸化物粉末を用いた本発明の触媒製造方法として
は、例えば活性アルミナ粉末と、該セリウムとジルコニ
ウムを含む酸化物粉末を湿式にて混合し水溶性スラリー
を調製し、セラミック製または金属製のモノリス担体に
塗布し、 乾燥、焼成後さらにPt、RhおよびPbから成る群から選
ばれた少なくとも１種の貴金属を含む水溶液に浸漬し、
再び乾燥、焼成を行なうことによって目的の触媒を得る
方法がある。As a catalyst production method of the present invention using the above oxide powder, for example, activated alumina powder, the oxide powder containing cerium and zirconium is mixed in a wet manner to prepare a water-soluble slurry, ceramic or metal After coating on a monolithic carrier, drying and firing, it is further immersed in an aqueous solution containing at least one noble metal selected from the group consisting of Pt, Rh and Pb,
There is a method of obtaining the target catalyst by performing drying and calcining again.
また、別の触媒製造法の例としては、予め貴金属を担
持したアルミナ粉末と該セリウムとジルコニウムを含む
酸化物粉末を湿式にて混合し水溶性スラリーを調製し、
セラミック製または金属製のモノリス担体に塗布し、乾
燥、焼成する方法がある。Further, as an example of another catalyst production method, a water-soluble slurry is prepared by mixing in advance an alumina powder carrying a noble metal and an oxide powder containing cerium and zirconium in a wet manner,
There is a method of applying to a ceramic or metal monolith carrier, drying and firing.
これらいずれの触媒製造工程においても、用いられる
ウォッシュコートスラリー中にセリウムとジルコニウム
を含む酸化物粉末を添加する工程が含まれることによっ
て、得られる触媒は、本発明の目的に合致した優れた排
ガス浄化性能を有するものとなる。In any of these catalyst production processes, the step of adding an oxide powder containing cerium and zirconium to the washcoat slurry used includes an excellent catalyst for purifying exhaust gas that meets the object of the present invention. It has performance.
本発明で用いられるセリウムとジルコニウムを含む酸
化物粉末の組成としては、ジルコニウム金属の含有量が
10〜50モル％で、残部がセリウムを主成分とする希土類
元素からなるものが好ましい。As the composition of the oxide powder containing cerium and zirconium used in the present invention, the content of zirconium metal is
It is preferable that the content is 10 to 50 mol% and the balance is made of a rare earth element containing cerium as a main component.
ジルコニウム含有量が10モル％未満ではO2ストレージ
能の向上が充分に得られず。ジルコニウム含有量が50モ
ル％を超すと本来酸化セリウムが持っているO2ストレー
ジ能が十分に得られなくなる。If the zirconium content is less than 10 mol%, the O 2 storage capacity cannot be sufficiently improved. If the zirconium content exceeds 50 mol%, the O 2 storage capacity inherently provided by cerium oxide cannot be sufficiently obtained.
また、本発明で用いるセリウムとジルコニウムを含む
酸化物粉末の触媒への添加量としては、触媒容量１当
り20〜100gで、モノリス担体に塗布される触媒層固形分
中15〜60重量％であることが好ましい。添加量がこれよ
り少ない場合は、添加効果は認められるものの、活性ア
ルミナ、あるいは活性アルミナ層を形成させた後のモノ
リス担体にセリウムおよびジルコニウムを硝酸塩水溶液
等により含浸担持させる方法によって製造される触媒に
あっても活性アルミナ等の細孔の閉塞はさほど顕著に起
こらないため、本発明による触媒性能上の優位性は十分
に発揮されない。また、添加量が上記数値を超える場合
には、有意な添加量増量効果がみられなくなる。The amount of the oxide powder containing cerium and zirconium used in the present invention added to the catalyst is 20 to 100 g per catalyst capacity, and 15 to 60% by weight based on the solid content of the catalyst layer applied to the monolithic carrier. Is preferred. When the addition amount is less than this, although the effect of addition is recognized, activated alumina, or a catalyst produced by a method of impregnating and supporting cerium and zirconium on a monolithic carrier after forming an active alumina layer with a nitrate aqueous solution or the like. Even if activated, the pores of activated alumina and the like are not blocked so much, and the superiority in catalytic performance according to the present invention is not sufficiently exhibited. On the other hand, if the added amount exceeds the above value, no significant effect of increasing the added amount is observed.
（作 用） この発明では、セリウムとジルコニウムのイオンを含
む水溶液から沈澱生成反応（共沈法）を用いて製造され
たセリウムとジルコニウムを含む酸化物粉末と貴金属を
含むかまたは含まないアルミナ粉末とを用いて水性スラ
リーを調整し、モノリス担体に塗布する工程を経て触媒
を製造する。(Operation) In the present invention, an oxide powder containing cerium and zirconium produced from an aqueous solution containing ions of cerium and zirconium by a precipitation reaction (coprecipitation method) and an alumina powder containing or not containing a noble metal are used. Aqueous slurry is prepared by using, and a catalyst is produced through a step of applying the slurry to a monolithic carrier.
本発明の排ガス浄化用触媒の製造方法によれば、セリ
ウムとジルコニウムは触媒のコート層中において、それ
ぞれの酸化物粉末を混合するだけでは得られない強い相
互作用を有し、酸化セリウムが本来持っているO2ストレ
ージ能およびその耐熱性が大きく改善されている。According to the method for producing an exhaust gas purifying catalyst of the present invention, cerium and zirconium have a strong interaction in the coat layer of the catalyst that cannot be obtained by merely mixing the respective oxide powders, and cerium oxide originally has and O 2 storage ability and heat resistance are is greatly improved.
第１図に、TPR（昇温還元）法により、本発明にて用
いられるセリウムとジルコニウムを含む酸化物粉末（実
施例１で用いたもの）、通常の酸化セリウム粉末、及び
酸化セリウム粉末と酸化ジルコニウム粉末の混合物につ
き、それぞれを加熱処理した後、H2−Arガスを流通させ
て酸素放出挙動をH2の消費量により測定した結果を示
す。図面中曲線Ａは上記通常の酸化セリウム（600℃熱
処理、BET比表面積＝35m2/g）、曲線Ｂは上記酸化セリ
ウム粉末と酸化ジルコニウム粉末の混合物（600℃熱処
理、BET比表面積＝37m2/g）、曲線Ｃはアンモニア沈澱
法で調製した上記セリウムとジルコニウムを含む酸化物
粉末（850℃熱処理、BET比表面積＝12m2/g）について測
定した結果を示す。FIG. 1 shows an oxide powder containing cerium and zirconium used in the present invention (the one used in Example 1), a normal cerium oxide powder, and a cerium oxide powder and an oxide The results of measuring the oxygen release behavior of the mixture of zirconium powders based on the consumption of H 2 after heating each of them and then passing H 2 —Ar gas through the mixture are shown. Drawings in curve A the normal cerium oxide (600 ° C. heat treatment, BET specific surface area = 35m 2 / g), curve B the cerium oxide powder and a mixture of zirconium oxide powder (600 ° C. heat treatment, BET specific surface area = 37m 2 / g) and curve C show the results measured for the oxide powder containing cerium and zirconium prepared by the ammonia precipitation method (heat treatment at 850 ° C., BET specific surface area = 12 m 2 / g).
排ガス浄化反応において有効な低温側（450〜500℃）
での酸素放出能において、本発明によるものは明らかに
他に比べて優れた酸素放出能を有する。Effective low temperature side (450-500 ℃) in exhaust gas purification reaction
In terms of the oxygen releasing ability, the one according to the present invention clearly has an excellent oxygen releasing ability as compared with others.
また、通常の酸化セリウムの場合低温側での酸素放出
能はその比表面積に応じて高くなることが知られている
が、本発明にて用いられるセリウムとジルコニウムを含
む酸化物粉末は熱処理によってその比表面積が小さくな
った場合にも、多量の酸素を放出する。Also, in the case of ordinary cerium oxide, it is known that the oxygen releasing ability on the low-temperature side increases according to its specific surface area, but the oxide powder containing cerium and zirconium used in the present invention is subjected to heat treatment. Even when the specific surface area is reduced, a large amount of oxygen is released.
従って、本発明においては、主となるセリウムとジル
コニウムの複合効果は、酸化セリウムの表面積を高く保
つ（あるいは高温での表面積の低下を抑制する）効果で
はなく、セリウムとジルコニウムの固溶によって、酸化
物格子酸素の脱離が容易になるバルク性質の変化に起因
するものと考えられる。Therefore, in the present invention, the main composite effect of cerium and zirconium is not the effect of keeping the surface area of cerium oxide high (or suppressing the decrease in surface area at high temperatures), but the solid solution of cerium and zirconium. This is considered to be due to a change in bulk properties that facilitates desorption of the lattice oxygen.
更に本発明の排ガス浄化用触媒の製造方法によれば、
セリウムおよびジルコニウムは酸化物としてミクロ的に
活性アルミナとは独立した粒子として存在するため、貴
金属の担持体としてのアルミナに要求される細孔構造、
あるいは触媒コート層に要求される孔構造を部分的にも
閉塞することが回避されることにより、貴金属の分散性
あるいは排ガスの拡散性が確保され、高い排ガス浄化性
能を得ることができる。Furthermore, according to the method for producing an exhaust gas purifying catalyst of the present invention,
Since cerium and zirconium exist as oxides in the form of particles that are microscopically independent of activated alumina, the pore structure required for alumina as a support for precious metals,
Alternatively, by avoiding even partially blocking the pore structure required for the catalyst coat layer, the dispersibility of the noble metal or the diffusibility of the exhaust gas is secured, and high exhaust gas purification performance can be obtained.
同時に、硝酸塩などの溶液を用い活性アルミナあるい
はアルミナコート層に助触媒成分を含浸担持する方法に
おいては、当然アルミナの吸水性やCe（Zr）出発塩の溶
解性によってその触媒への添加量が制限されるが、本発
明の方法ではコートスラリ調製時の配合比、あるいは、
スラリー塗布量によって多量のセリウム（ジルコニウ
ム）を触媒に添加することができ、自動車排ガスなど排
ガス組成が酸化雰囲気と還元雰囲気との間で変動する場
合に、その使用条件に応じて十分な添加量を設定するこ
とが可能になっている。At the same time, in the method of impregnating and supporting the co-catalyst component on the activated alumina or alumina coat layer using a solution such as nitrate, the amount added to the catalyst is naturally limited by the water absorption of alumina and the solubility of the Ce (Zr) starting salt. However, in the method of the present invention, the mixing ratio at the time of coating slurry preparation, or,
A large amount of cerium (zirconium) can be added to the catalyst depending on the amount of slurry applied. When the composition of exhaust gas such as automobile exhaust gas fluctuates between an oxidizing atmosphere and a reducing atmosphere, a sufficient amount of cerium (zirconium) must be added according to the usage conditions. It is possible to set.
このような作用効果により、本発明の排ガス浄化用触
媒の製造方法により製造された触媒は優れたO2ストレー
ジ能を有し、そのため、とくに高温耐久後において優れ
た排ガス浄化性能を有する。Due to such effects, the catalyst produced by the method for producing an exhaust gas purifying catalyst of the present invention has excellent O 2 storage ability, and therefore has excellent exhaust gas purifying performance, especially after high-temperature durability.
（実施例） 以下、この発明を、実施例、比較例および試験例によ
り説明する。(Examples) Hereinafter, the present invention will be described with reference to examples, comparative examples, and test examples.
実施例１ 硝酸セリウムと硝酸ジルコニルの混合水溶液（Ce濃度
0.9モル／、Zr濃度0.3モル／）を調製し撹拌をしな
がら、アンモニア水溶液を除々に加え溶液のpHを9.0に
し、約１時間撹拌を行なった。Example 1 A mixed aqueous solution of cerium nitrate and zirconyl nitrate (Ce concentration
An aqueous ammonia solution was gradually added to adjust the solution pH to 9.0 while stirring and preparing 0.9 mol /, Zr concentration 0.3 mol /), and the mixture was stirred for about 1 hour.
その後、生成した水酸化物の沈澱を吸引濾過し、沈澱
物を120℃で約４時間乾燥した後600℃で約２時間焼成し
てセリウムとジルコニウムを含む酸化物粉末を得た（Zr
25モル％、BET比表面積＝55m2/g）。Thereafter, the precipitate of the formed hydroxide was filtered by suction, and the precipitate was dried at 120 ° C. for about 4 hours and calcined at 600 ° C. for about 2 hours to obtain an oxide powder containing cerium and zirconium (Zr
25 mol%, BET specific surface area = 55 m 2 / g).
上記酸化物粉末384g、Ceを３重量％担持し熱安定化し
た活性アルミナ粉末（BET比表面積120m2/g）1392g、お
よび硝酸酸性アルミナゾル（ベーマイトアルミナ10重量
％懸濁液に、10重量％硝酸水溶液を加えて得られたゾ
ル）2222gとを磁性ボールミルに投入し、混合粉砕して
スラリー液を得た。384 g of the above oxide powder, 1392 g of thermally stabilized activated alumina powder (BET specific surface area 120 m 2 / g) carrying 3 wt% of Ce, and 10 wt% nitric acid in a nitric acid acidic alumina sol (10 wt% suspension of boehmite alumina) 2222 g of a sol obtained by adding an aqueous solution) was charged into a magnetic ball mill, and mixed and pulverized to obtain a slurry liquid.
このスラリー液にコージエライト質モノリス担体（1.
3）を浸漬し、引き上げた後、空気流にてセル内の余
剰のスラリーを取り除いて乾燥し650℃で２時間空気中
で焼成する工程を２回繰り返し、コート層重量200g/
−担体のコーティング担体を得た。A cordierite monolithic carrier (1.
3) After dipping and lifting, the process of removing excess slurry in the cell with an air stream, drying and baking in air at 650 ° C. for 2 hours is repeated twice to obtain a coat layer weight of 200 g /
-Coating of the carrier A carrier was obtained.
得られたコーティング担体にジニトロジアンミン白金
硝酸溶液と硝酸ロジウム溶液を用い、含浸法により白
金、ロジウムを担持したのち、乾燥し、燃焼ガス気流中
400℃で２時間焼成し、（触媒−１）を得た。Using a dinitrodiammine platinum nitrate solution and a rhodium nitrate solution on the obtained coating carrier, platinum and rhodium are supported by an impregnation method, then dried, and then dried in a combustion gas stream.
It was calcined at 400 ° C. for 2 hours to obtain (catalyst-1).
実施例２ 実施例１と同様の活性アルミナ粉末を撹拌しながら、
ジニトロジアンミン白金硝酸溶液を噴霧し、乾燥後、空
気中400℃で２時間焼成して白金担持量1.0重量％のPt担
持アルミナを得た。また、硝酸ロジウム溶液を用い、同
様の方法でロジウム担持量1.0重量％のロジウム担持ア
ルミナ粉末を得た。Example 2 While stirring the same activated alumina powder as in Example 1,
A dinitrodiammine platinum nitrate solution was sprayed, dried and calcined in air at 400 ° C. for 2 hours to obtain a Pt-supported alumina having a platinum support amount of 1.0% by weight. Using a rhodium nitrate solution, rhodium-carrying alumina powder having a rhodium carrying amount of 1.0% by weight was obtained in the same manner.
実施例１と同様のセリウムとジルコニウムを含む酸化
物粉末を384g、上記白金担持アルミナ粉末1265g、同ロ
ジウム粉末127gおよび硝酸酸性アルミナゾル2222gを磁
性ボールミルに投入し、混合粉砕してスラリー液を得
た。384 g of the same oxide powder containing cerium and zirconium as in Example 1, 1265 g of the above platinum-supported alumina powder, 127 g of the same rhodium powder and 2222 g of nitric acid acidic alumina sol were charged into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid.
このスラリー液を用い実施例１と同様の方法でモノリ
ス担体に塗布し、アルミナコート層重量200g/−担体
の（触媒−２）を得た。Using this slurry liquid, a monolith carrier was applied in the same manner as in Example 1 to obtain (catalyst-2) having an alumina coat layer weight of 200 g / carrier.
比較例１ 酸化セリウム粉末（BET比表面積＝110m2/g）と酸化ジ
ルコニウム粉末（BET比表面積＝50m2/g）の混合物（Zr2
5モル％相当）を用いたこと以外は実施例１と同様の方
法で触媒を調製し（触媒−３）を得た。Comparative Example 1 A mixture (Zr2) of cerium oxide powder (BET specific surface area = 110 m 2 / g) and zirconium oxide powder (BET specific surface area = 50 m 2 / g)
A catalyst was prepared in the same manner as in Example 1 except that 5 mol%) was used (catalyst-3).
比較例２ Ceを３重量％担持し熱安定化した活性アルミナ粉末
（BET比表面積120m2/g）1776g、および硝酸酸性アルミ
ナゾル2222gとを磁性ボールミルに投入し、混合粉砕し
てスラリー液を得た。Comparative Example 2 1776 g of thermally stabilized activated alumina powder (BET specific surface area: 120 m 2 / g) carrying 3% by weight of Ce and 2222 g of nitric acid acidic alumina sol were charged into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid. .
このスラリー液を用い、実施例１と同様の方法でコー
ティングを行い、コート量160g/のコート担体を得
た。Using this slurry liquid, coating was performed in the same manner as in Example 1 to obtain a coated carrier having a coating amount of 160 g /.
上記コート担体を、セリウム1.5モル／、ジルコニ
ウム0.5モリ／をそれぞれ含む硝酸セリウムと硝酸ジ
ルコニルの混合溶液に１分間浸漬し、吸水させた後乾燥
し、650℃２時間空気中で焼成してコート量200g/のコ
ート担体を得た。The coated carrier is immersed in a mixed solution of cerium nitrate and zirconyl nitrate containing 1.5 mol / cerium and 0.5 mol / zirconium for 1 minute, absorbed, dried, baked in air at 650 ° C. for 2 hours, and baked in air. 200 g / coated carrier was obtained.
得られたコーティング担体にジニトロジアンミン白金
硝酸溶液と硝酸ロジウム溶液を用い、含浸法により白
金、ロジウムを担持したのち、乾燥し、燃焼ガス気流中
400℃で２時間焼成し、（触媒−４）を得た。Using a dinitrodiammine platinum nitrate solution and a rhodium nitrate solution on the obtained coating carrier, platinum and rhodium are supported by an impregnation method, then dried, and then dried in a combustion gas stream.
It was calcined at 400 ° C. for 2 hours to obtain (catalyst-4).
実施例３ 実施例１と同様のセリウムとジルコニウムを含む酸化
物粉末を用い、コーティングスラリーの配合を、上記酸
化物粉末96g、Ceを３重量％担持し熱安定化した活性ア
ルミナ粉末（BET比表面積120m2/g）1682g、および硝酸
酸性アルミナゾル2222gとした以外は実施例１と同様の
方法で（触媒−５）を得た。Example 3 Using the same oxide powder containing cerium and zirconium as in Example 1, the coating slurry was mixed with 96 g of the above oxide powder and 3% by weight of Ce to support thermally activated activated alumina powder (BET specific surface area). (Catalyst-5) was obtained in the same manner as in Example 1, except that 1682 g of 120 m 2 / g) and 2222 g of nitric acid acidic alumina sol were used.
比較例３ 比較例１で用いた、酸化セリウム粉末と酸化ジルコニ
ウム粉末の混合物（Zr25モル％）を用いたこと以外は実
施例３と同様の方法で（触媒−６）を得た。Comparative Example 3 (Catalyst-6) was obtained in the same manner as in Example 3 except that the mixture of cerium oxide powder and zirconium oxide powder (Zr 25 mol%) used in Comparative Example 1 was used.
比較例４ 比較例２で調製したアルミナコート担体を用い、コー
ト担体を、セリウム0.4モル／、ジルコニウム0.13モ
ル／をそれぞれ含む硝酸セリウムと硝酸ジルコニルの
混合溶液に１分間浸漬し、吸水させた以外は比較例２と
同様の方法で（触媒−７）を得た。Comparative Example 4 Except for using the alumina-coated carrier prepared in Comparative Example 2 and immersing the coated carrier in a mixed solution of cerium nitrate and zirconyl nitrate containing 0.4 mol / cerium and 0.13 mol / zirconium, respectively, for 1 minute and absorbing water, (Catalyst-7) was obtained in the same manner as in Comparative Example 2.
実施例４ 硝酸セリウムと硝酸ジルコニルの混合水溶液（Ce濃度
0.5モル／、Zr濃度0.5モル／）を調製し、その後実
施例１と同様の方法でセリウムとジルコニウムを含む酸
化物粉末を得た（Zr50モル％）。Example 4 A mixed aqueous solution of cerium nitrate and zirconyl nitrate (Ce concentration
0.5 mol /, Zr concentration 0.5 mol /) was prepared, and then an oxide powder containing cerium and zirconium was obtained in the same manner as in Example 1 (Zr 50 mol%).
さらに実施例１と同様の方法で触媒を調製し、（触媒
−８）を得た。Further, a catalyst was prepared in the same manner as in Example 1 to obtain (Catalyst-8).
実施例５ 硝酸セリウムと硝酸ジルコニルの混合水溶液（Ce濃度
0.9モル／、Zr濃度0.3モル／）を調製し撹拌をしな
がら、アンモニア水溶液を徐々に加え溶液のpHを9.0に
し、約１時間撹拌を行なった。Example 5 A mixed aqueous solution of cerium nitrate and zirconyl nitrate (Ce concentration
An aqueous ammonia solution was gradually added to adjust the solution pH to 9.0 while stirring and preparing 0.9 mol /, Zr concentration 0.3 mol /), and the mixture was stirred for about 1 hour.
その後、生成した水酸化物の沈澱を吸引濾過し、沈澱
物を120℃で約４時間乾燥した後600℃で約２時間焼成し
てセリウムとジルコニウムを含む酸化物粉末を得た（Zr
25モル％、BET比表面積＝55m2/g）。Thereafter, the precipitate of the formed hydroxide was filtered by suction, and the precipitate was dried at 120 ° C. for about 4 hours and calcined at 600 ° C. for about 2 hours to obtain an oxide powder containing cerium and zirconium (Zr
25 mol%, BET specific surface area = 55 m 2 / g).
上記酸化物粉末384g、Ceを３重量％担持し熱安定化し
た活性アルミナ粉末（BET比表面積120m2/g）1392g、お
よび硝酸酸性アルミナゾル（ベーマイトアルミナ10重量
％懸濁液に、10重量％硝酸水溶液を加えて得られたゾ
ル）2222gとを磁性ボールミルに投入し、混合粉砕して
スラリー液を得た。384 g of the above oxide powder, 1392 g of thermally stabilized activated alumina powder (BET specific surface area 120 m 2 / g) carrying 3 wt% of Ce, and 10 wt% nitric acid in a nitric acid acidic alumina sol (10 wt% suspension of boehmite alumina) 2222 g of a sol obtained by adding an aqueous solution) was charged into a magnetic ball mill, and mixed and pulverized to obtain a slurry liquid.
このスラリー液にコージエライト質モノリス担体（1.
3）を浸漬し、引き上げた後、空気流にてセル内の余
剰のスラリーを取り除いて乾燥し650℃で２時間空気中
で焼成する工程を２回繰り返し、コート層重量200g/
−担体のコーティング担体を得た。A cordierite monolithic carrier (1.
3) After dipping and lifting, the process of removing excess slurry in the cell with an air stream, drying and baking in air at 650 ° C. for 2 hours is repeated twice to obtain a coat layer weight of 200 g /
-Coating of the carrier A carrier was obtained.
得られたコーティング担体に硝酸パラジウム溶液と硝
酸ロジウム溶液を用い、含浸法により白金、ロジウムを
担持したのち、乾燥し、燃焼ガス気流中400℃で２時間
焼成し、（触媒９）を得た。Using a palladium nitrate solution and a rhodium nitrate solution on the obtained coated carrier, platinum and rhodium were supported by an impregnation method, dried, and calcined in a combustion gas stream at 400 ° C. for 2 hours to obtain (catalyst 9).
比較例５ 酸化セリウム粉末（BET比表面積＝110m2/g）と酸化ジ
ルコニウム粉末（BET比表面積＝50m2/g）の混合物（Zr2
5モル％相当）を用いたこと以外は実施例５と同様の方
法で触媒を調製し（触媒10）を得た。Comparative Example 5 A mixture (Zr2) of cerium oxide powder (BET specific surface area = 110 m 2 / g) and zirconium oxide powder (BET specific surface area = 50 m 2 / g)
A catalyst was prepared in the same manner as in Example 5 except that 5 mol%) was used (catalyst 10).
試験例１ 実施例１〜５、比較例１〜５の各触媒（触媒１〜12）
に付き蛍光Ｘ線法により、触媒中の貴金属およびセリウ
ム、ジルコニウムの含有量を分析した。Test Example 1 Catalysts of Examples 1 to 5 and Comparative Examples 1 to 5 (Catalysts 1 to 12)
The catalysts were analyzed for the content of noble metals and cerium and zirconium by a fluorescent X-ray method.
触媒１〜８はいずれも触媒１当り、白金約1.12g、
ロジウム約0.11gを含んでいた。Catalysts 1 to 8 were all about 1.12 g of platinum per catalyst,
It contained about 0.11 g of rhodium.
触媒9,10はいずれも触媒１当りパラジウム約1.12
g、ロジウム約0.11gを含んでいた。Catalysts 9 and 10 each had about 1.12 palladium per catalyst.
g, about 0.11 g of rhodium.
触媒１〜４はいずれも触媒１当り酸化物換算で、セ
リア約32g、ジルコニア約8gを含んでいた（Ce:Zrモル比
＝75:25）。Each of the catalysts 1 to 4 contained about 32 g of ceria and about 8 g of zirconia in terms of oxide per catalyst (Ce: Zr molar ratio = 75: 25).
触媒５〜７はいずれも触媒１当り酸化物換算で、セ
リア約8g、ジルコニア約2gを含んでいた（Ce:Zrモル比
＝75:25）。Each of the catalysts 5 to 7 contained about 8 g of ceria and about 2 g of zirconia in terms of oxide per catalyst (Ce: Zr molar ratio = 75: 25).
触媒８は触媒１当り酸化物換算で、セリア約23g、
ジルコニア約17gを含んでいた（Ce:Zrモル比50:50）。The catalyst 8 is about 23 g of ceria in terms of oxide per catalyst,
It contained about 17 g of zirconia (Ce: Zr molar ratio 50:50).
触媒9,10はいずれも触媒１当り酸化物換算で、セリ
ア約32g、ジルコニア約8gを含んでいた（Ce:Zrモル比＝
75:25）。Each of the catalysts 9 and 10 contained about 32 g of ceria and about 8 g of zirconia in terms of oxide per catalyst (Ce: Zr molar ratio =
75:25).
試験例２ 実施例１〜５、比較例１〜５の各触媒（触媒１〜10）
に付き、下記条件でエンジン耐久性能評価を行い、耐久
劣化触媒のHC、CO、NOx浄化率を測定した。Test Example 2 Catalysts of Examples 1 to 5 and Comparative Examples 1 to 5 (Catalysts 1 to 10)
, Engine durability performance was evaluated under the following conditions, and the HC, CO, and NOx purification rates of the durability deterioration catalyst were measured.
性能評価結果を第１表に示す。 Table 1 shows the performance evaluation results.
＜エンジン耐久条件＞ 触媒入口排ガス温度 850℃ 耐久時間 100時間 エンジン 排気量2200cc 燃料 無鉛ガソリン 耐久中入口エミッション CO 0.4〜0.6％ O2 0.5±0.1％ NO 約1000ppm HC 約2500ppm CO2 14.9±0.1％ ＜性能評価条件＞ 触媒入口排ガス温度 400℃ エンジン 排気量2000cc 燃料 無鉛ガソリン 平均空燃比（制御中心値） 14.6 （発明の効果） 以上説明してきたようにこの発明によれば、 セリウムとジルコニウムのイオンを含む水溶液から沈
澱生成反応を用いて製造されたセリウムとジルコニウム
を含む酸化物粉末を用いる触媒製造方法としたため、他
のセリウムおよびジルコニウム添加方法に比べて、高温
耐久後の排ガス浄化性能において明らかに優れる触媒が
得られる。<Engine endurance condition> Catalyst inlet exhaust gas temperature 850 ° C Endurance time 100 hours Engine Displacement 2200cc Fuel Unleaded gasoline Endurance inlet emission CO 0.4 ~ 0.6% O 2 0.5 ± 0.1% NO About 1000ppm HC About 2500ppm CO 2 14.9 ± 0.1% < Performance evaluation conditions> Catalyst inlet exhaust gas temperature 400 ℃ Engine Displacement 2000cc Fuel Unleaded gasoline Average air-fuel ratio (control center value) 14.6 (Effects of the Invention) As described above, according to the present invention, a catalyst production method using an oxide powder containing cerium and zirconium produced by a precipitation reaction from an aqueous solution containing ions of cerium and zirconium is provided. As compared with other cerium and zirconium addition methods, a catalyst which is clearly superior in exhaust gas purification performance after high-temperature durability can be obtained.
その理由としては、これまでに述べたように、本発明
の触媒製造法によって得られる触媒においては、セリウ
ムとジルコニウムの強い相互作用により高いO2ストレー
ジ能を有し、かつ、コート層の細孔構造が維持されてい
るため貴金属分散性あるいは排ガスの拡散性が確保され
ていることによると考えられる。The reason is that, as described so far, in the catalysts obtainable by the catalyst preparation process of the present invention, has a high O 2 storage capability by strong interaction of cerium and zirconium, and the pores of the coat layer It is considered that the preservation of the structure ensures the dispersion of the noble metal or the diffusion of the exhaust gas.
尚、試験例２の結果、および上記本発明の効果の発現
理由いずれからも明らかなように、本発明の効果はセリ
ウムおよびジルコニウム添加量の比較的大きい場合に顕
著であり、また、セリウムとジルコニウムの比率に好適
な範囲が存在する。Incidentally, as is clear from both the results of Test Example 2 and the reason why the effects of the present invention were manifested, the effects of the present invention were remarkable when the added amounts of cerium and zirconium were relatively large. There is a suitable range for the ratio.
第１図は昇温還元法による酸素放出能の測定結果を示す
曲線図である。FIG. 1 is a curve diagram showing the measurement results of the oxygen releasing ability by the temperature-reduction reduction method.
Claims (3)
よびパラジウムから成る群から選ばれた少なくとも１種
の貴金属と、活性アルミナと、セリウムおよびジルコニ
ウムを含んでなる触媒担持層を設けるモノリス型排ガス
浄化用触媒の製造方法において、少なくとも、セリウム
とジルコニウムのイオンを含むpH9.0の水溶液から沈澱
生成反応を用いて製造されたセリウムとジルコニウムを
含み、かつ該ジルコニウムの含有量が10〜50モル％で、
残部が前記セリウムを主成分とする希土類元素である酸
化物粉末と、 貴金属を含むかまたは含まないアルミナ粉末とを用いて
水性スラリーを調製し、モノリス担体に塗布する工程を
有することを特徴とする排ガス浄化用触媒の製造方法。1. A monolith-type exhaust gas purification comprising a catalyst supporting layer comprising at least one noble metal selected from the group consisting of platinum, rhodium and palladium, activated alumina, and cerium and zirconium on the surface of a monolith-type carrier. In the method for producing a catalyst for use, at least contains cerium and zirconium produced by a precipitation reaction from an aqueous solution of pH 9.0 containing ions of cerium and zirconium, and the content of zirconium is 10 to 50 mol%. ,
The balance is characterized by comprising a step of preparing an aqueous slurry using an oxide powder that is a rare earth element containing cerium as a main component and an alumina powder containing or not containing a noble metal, and applying the slurry to a monolithic carrier. A method for producing an exhaust gas purifying catalyst.
の添加量は触媒1L当たり20g〜100gで、かつ、モノリス
担体に塗布される触媒層固形分中15〜60重量％であるこ
とを特徴とする請求項１記載の排ガス浄化用触媒の製造
方法。2. The addition amount of the oxide powder containing cerium and zirconium is 20 to 100 g per liter of the catalyst, and is 15 to 60% by weight in the solid content of the catalyst layer applied to the monolithic carrier. A method for producing an exhaust gas purifying catalyst according to claim 1.
熟成してセリウムとジルコニウムを含む酸化物粉末を沈
澱生成することを特徴とする請求項１記載の排ガス浄化
用触媒の製造方法。3. Stirring at pH = 9.0 and at least 1 hour,
2. The method for producing an exhaust gas purifying catalyst according to claim 1, wherein the aging is performed to precipitate oxide powder containing cerium and zirconium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1269202A JP2578219B2 (en) | 1989-10-18 | 1989-10-18 | Method for producing exhaust gas purifying catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1269202A JP2578219B2 (en) | 1989-10-18 | 1989-10-18 | Method for producing exhaust gas purifying catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03131343A JPH03131343A (en) | 1991-06-04 |
| JP2578219B2 true JP2578219B2 (en) | 1997-02-05 |
Family
ID=17469097
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1269202A Expired - Lifetime JP2578219B2 (en) | 1989-10-18 | 1989-10-18 | Method for producing exhaust gas purifying catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2578219B2 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2699524B1 (en) * | 1992-12-21 | 1995-02-10 | Rhone Poulenc Chimie | Composition based on a mixed oxide of cerium and zirconium, preparation and use. |
| FR2701472B1 (en) * | 1993-02-10 | 1995-05-24 | Rhone Poulenc Chimie | Process for the preparation of compositions based on mixed oxides of zirconium and cerium. |
| FR2701471B1 (en) | 1993-02-10 | 1995-05-24 | Rhone Poulenc Chimie | Process for the synthesis of compositions based on mixed oxides of zirconium and cerium, compositions thus obtained and uses of the latter. |
| FR2714370B1 (en) * | 1993-12-24 | 1996-03-08 | Rhone Poulenc Chimie | Precursor of a composition and composition based on a mixed oxide of cerium and zirconium, method of preparation and use. |
| FR2720296B1 (en) * | 1994-05-27 | 1996-07-12 | Rhone Poulenc Chimie | Compounds based on alumina, cerium oxide and zirconium oxide with high reducibility, process for their preparation and their use in the preparation of catalysts. |
| US5958827A (en) | 1995-12-07 | 1999-09-28 | Toyota Jidosha Kabushiki Kaisha | Solid solution particle of oxides, a process for producing the same and a catalyst for purifying exhaust gases |
| DE69728341T2 (en) | 1996-10-07 | 2004-12-30 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Compound oxide, composite oxide carrier and catalyst |
| JP4382180B2 (en) * | 1998-11-06 | 2009-12-09 | 株式会社キャタラー | Exhaust gas purification catalyst |
| US6335305B1 (en) | 1999-01-18 | 2002-01-01 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Catalyst for purifying exhaust gas |
| JP4513565B2 (en) * | 2004-12-28 | 2010-07-28 | マツダ株式会社 | Exhaust gas purification catalyst |
| WO2009120866A1 (en) * | 2008-03-27 | 2009-10-01 | Umicore Ag & Co. Kg | Base metal and base metal modified diesel oxidation catalysts |
| JP4674264B2 (en) * | 2009-07-31 | 2011-04-20 | 株式会社キャタラー | Exhaust gas purification catalyst |
-
1989
- 1989-10-18 JP JP1269202A patent/JP2578219B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03131343A (en) | 1991-06-04 |
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