JP2734808B2 - Exhaust gas purification catalyst - Google Patents
Exhaust gas purification catalystInfo
- Publication number
- JP2734808B2 JP2734808B2 JP3133277A JP13327791A JP2734808B2 JP 2734808 B2 JP2734808 B2 JP 2734808B2 JP 3133277 A JP3133277 A JP 3133277A JP 13327791 A JP13327791 A JP 13327791A JP 2734808 B2 JP2734808 B2 JP 2734808B2
- Authority
- JP
- Japan
- Prior art keywords
- cerium
- zirconium
- aqueous solution
- 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.)
- Expired - Lifetime
Links
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、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（H
C) 、一酸化炭素（CO) 、窒素酸化物（NOx)を効率よく
浄化する排ガス浄化用触媒に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the use of hydrocarbons (H
The present invention relates to an exhaust gas purifying catalyst that efficiently purifies C), carbon monoxide (CO), and nitrogen oxide (NOx).
【０００２】[0002]
【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は種々提案
されている。なかでも貴金属を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、特開昭61-15734
7 号公報、特開平1-123636号公報に開示されているよう
に、モノリス担体にセリウム、ジルコニウムそれぞれの
酸化物あるいは炭酸塩粉末を活性アルミナ等と混合塗布
して熱処理した触媒や、特開昭63-116741 号公報、特開
平1-281144号公報に開示されているように、酸化セリウ
ムの持つO2ストレージ能向上を目的とし、セリウムを主
成分とするセリウム、ジルコニウム酸化物を添加した触
媒が提案されている。2. Description of the Related Art Conventionally, various exhaust gas purifying catalysts for purifying HC, CO and NOx in exhaust gas discharged from an internal combustion engine have been proposed. Among them, the addition of an appropriate amount of cerium and zirconium to an exhaust gas purifying catalyst containing a noble metal as an active component improves the catalytic performance.
No. 7, JP-A No. 1-123636, and a catalyst prepared by mixing and coating an oxide or carbonate powder of cerium and zirconium with activated alumina on a monolithic carrier and heat-treating the same. 63-116741 discloses, as disclosed in JP-a-1-281144, for the purpose of the O 2 storage ability improves with the cerium oxide, cerium composed mainly of cerium, the catalyst is obtained by adding zirconium oxide Proposed.
【０００３】[0003]
【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においては、その製造工程
でセリウムおよびジルコニウムを排ガス浄化用触媒へ添
加するにあっては、 1) セリウム、ジルコニウムのそれぞれの酸化物あるい
は炭酸塩粉末を活性アルミナ等と混合添加して熱処理す
る方法ではセリウム、ジルコニウムは複合化されにく
く、複合化等の相互作用による助触媒作用は充分に得ら
れない。 2) また、従来報告されているセリウム、ジルコニウム
酸化物は、酸化セリウムを主成分としこれにジルコニウ
ム等を添加したものであるが、貴金属によってはセリウ
ムを主成分とする酸化物が必ずしも触媒作用向上に有効
とはならない。等の問題点があった。However, in such a conventional exhaust gas purifying catalyst, when cerium and zirconium are added to the exhaust gas purifying catalyst in the production process, 1) each of cerium and zirconium is added. In the method of heat-treating by mixing and adding an oxide or carbonate powder of the above with activated alumina or the like, cerium and zirconium are not easily compounded, and a sufficient co-catalyst effect due to interaction such as compounding cannot be obtained. 2) In addition, cerium and zirconium oxides reported so far contain cerium oxide as a main component and zirconium or the like added thereto. However, depending on a noble metal, an oxide containing cerium as a main component does not always improve the catalytic action. Is not valid. And so on.
【０００４】[0004]
【課題を解決するための手段】発明者は上記問題点に鑑
み、以下に述べる新規な触媒の製造方法および該方法に
より得られる触媒により、従来の問題点が解決されるこ
とを見出し、本発明を達成するに至った。すなわち、本
願発明の排ガス浄化用触媒の製造方法は、次の（１）〜
（４）の工程： （１）セリウムおよびジルコニウムのイオンを含有する
酸性水溶液に、アルカリ性水溶液を添加してセリウムお
よびジルコニウム含有沈殿生成物を生成し、 （２）得られたセリウムおよびジルコニウム含有沈殿生
成物を乾燥し、しかる後焼成して金属換算で１０〜３０
モル％のセリウムと７０〜９０モル％のジルコニウムを
含むセリウムおよびジルコニウム含有酸化物粉末を調製
し、 （３）得られたセリウムおよびジルコニウム含有酸化物
粉末と、ロジウム；又はロジウムおよび白金もしくはパ
ラジウムを含有する活性アルミナ粉末とを、湿式にて混
合しスラリーを調製し、次いで （４）得られたスラリーを担体に塗布し、しかる後乾燥
し、焼成する、を含んでなります。 更に、本発明の排ガス浄化用触媒の別の製造方法は、次
の（１）〜（５）の工程： （１）セリウムおよびジルコニウムのイオンを含有する
酸性水溶液に、アルカリ性水溶液を添加してセリウムお
よびジルコニウム含有沈殿生成物を生成し、 （２）得られたセリウムおよびジルコニウム含有沈殿生
成物を乾燥し、しかる後焼成して金属換算で１０〜３０
モル％のセリウムと７０〜９０モル％のジルコニウムを
含むセリウムおよびジルコニウム含有酸化物粉末を調製
し、 （３）得られたセリウムおよびジルコニウム含有酸化物
粉末を、湿式にて混合しスラリーを調製し、 （４）得られたスラリーを担体に塗布し、しかる後乾燥
し、焼成しセリウムおよびジルコニウムを担持した担体
を調製し、次いで （５）得られたセリウムおよびジルコニウムを担持した
担体を、ロジウム；又はロジウムおよび白金もしくはパ
ラジウムを含有する水溶液に浸漬し、乾燥しそして焼成
する、を含んでなります。更に本願発明は、前記製造方
法によって製造された排ガス浄化用触媒に関します。SUMMARY OF THE INVENTION In view of the above problems, the present inventors have found that the following problems can be solved by the novel method for producing a catalyst and the catalyst obtained by the method. Was achieved. That is, the method for producing an exhaust gas purifying catalyst of the present invention includes the following (1) to
Step (4): (1) An alkaline aqueous solution is added to an acidic aqueous solution containing cerium and zirconium ions to produce a cerium and zirconium-containing precipitation product. (2) The resulting cerium and zirconium-containing precipitation product The product is dried and then fired to obtain a metal equivalent of 10 to 30.
Preparing a cerium and zirconium-containing oxide powder containing mol% cerium and 70-90 mol% zirconium; (3) containing the obtained cerium and zirconium-containing oxide powder and rhodium; or rhodium and platinum or palladium. Activated alumina powder is mixed with a wet method to prepare a slurry, and then (4) the obtained slurry is applied to a carrier, then dried and calcined. Further, another method for producing the exhaust gas purifying catalyst of the present invention comprises the following steps (1) to (5): (1) An alkaline aqueous solution is added to an acidic aqueous solution containing cerium and zirconium ions. And a zirconium-containing precipitation product is produced. (2) The obtained cerium- and zirconium-containing precipitation product is dried, and then calcined to obtain a metal having a content of 10 to 30 in terms of metal.
Preparing cerium and zirconium-containing oxide powder containing cerium of 70% by mole and cerium and zirconium of 70 to 90% by mole, and (3) mixing the obtained cerium and zirconium-containing oxide powder by a wet method to prepare a slurry; (4) The obtained slurry is applied to a carrier, and then dried and calcined to prepare a carrier supporting cerium and zirconium. Then, (5) the obtained carrier supporting cerium and zirconium is converted to rhodium; or Immersing in an aqueous solution containing rhodium and platinum or palladium, drying and calcining. Further, the present invention relates to an exhaust gas purifying catalyst manufactured by the above-mentioned manufacturing method.
【０００５】本発明で用いられる該少くともセリウムと
ジルコニウムを含む酸化物は、排ガス浄化用触媒に使用
される貴金属のうち特にロジウムの触媒性能向上に大き
く寄与する。ここで、セリウムとジルコニウムを含む酸
化物の少くとも１部は、ジルコニウムを主成分とした複
合酸化物であることをＸＲＤ回折し、確認している。[0005] The oxide containing at least cerium and zirconium used in the present invention greatly contributes to the improvement of the catalytic performance of rhodium, particularly of the noble metals used in the exhaust gas purifying catalyst. Here, it is confirmed by XRD diffraction that at least a part of the oxide containing cerium and zirconium is a composite oxide containing zirconium as a main component.
【０００６】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セリウム、ジルコニウムのイオン
を含む酸性溶液に、アンモニア、尿素等を添加し、必要
に応じて加熱、加圧し、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。この酸化物粉末は含有する金属種として
セリウム、ジルコニウムのみから成るもので十分な触媒
性能向上効果が得られるが、セリウム源としてセリウム
を主成分とし、他の希土類（例えばLa、Nd、Pr、Y)をも
同時に含む低濃度のセリウム塩を用いてもよい。The oxide powder containing cerium and zirconium used in the present invention is prepared by adding ammonia, urea, etc. to an acidic solution containing ions of cerium and zirconium, such as a mixed aqueous solution of cerium nitrate and zirconium nitrate. Heating and pressurizing to form a precipitate such as hydroxide,
It can be produced by drying and calcining the obtained precipitate. This oxide powder can be used only for cerium and zirconium as the metal species to be contained, and a sufficient effect of improving the catalytic performance can be obtained. However, cerium source is mainly composed of cerium and other rare earths (for example, La, Nd, Pr, Y ) May be used at a low concentration.
【０００７】上記酸化物粉末を用いた本発明の触媒の製
造方法としては、例えば活性アルミナ粉末と、少くとも
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
混合して水性スラリーを調整し、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、焼成後さらにロジ
ウム或いはロジウムと白金またはパラジウムから成る貴
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。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と湿
式にて混合して水溶性スラリーを調整し、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。As a method for producing the catalyst of the present invention using the above oxide powder, for example, an aqueous slurry is prepared by mixing an activated alumina powder and at least the oxide powder containing cerium and zirconium in a wet manner. There is a method in which a target catalyst is obtained by coating on a ceramic or metal monolith carrier, drying and calcining, and further immersing in an aqueous solution containing rhodium or a noble metal composed of rhodium and platinum or palladium, followed by drying and calcining again. . As another example of a catalyst production method, a water-soluble slurry is prepared by mixing an alumina powder carrying a noble metal in advance and an oxide powder containing cerium and zirconium in a wet manner to prepare a ceramic or metal monolith. There is a method of applying to a carrier, drying and baking.
【０００８】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少くともセリ
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,
By including a step of adding an oxide powder containing at least cerium and zirconium to the washcoat slurry used, the resulting catalyst has excellent exhaust gas purification performance meeting the object of the present invention.
【０００９】本発明で用いられる少くともセリウムとジ
ルコニウムを含む酸化物粉末の組成としては、セリウム
金属の含有量が10〜30モル％で、残部がジルコニウムを
主成分とすることが好ましい。セリウム含有量が10モル
％未満ではセリウム、ジルコニウムの複合酸化物生成量
が充分とならず、セリウム含有量が30モル％より多くな
るとセリウムが固溶しきれずCeO2が生成し、充分な触媒
性能向上が得られなくなる。[0009] The composition of the oxide powder containing at least cerium and zirconium used in the present invention is preferably such that the content of cerium metal is 10 to 30 mol% and the remainder is mainly composed of zirconium. If the cerium content is less than 10 mol%, the amount of composite oxide of cerium and zirconium will not be sufficient, and if the cerium content is more than 30 mol%, cerium will not be able to form a solid solution and CeO 2 will be generated, resulting in sufficient catalytic performance. No improvement can be obtained.
【００１０】また、本発明で用いられる少くともセリウ
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１Ｌ当り２０ｇを超え１００ｇ以下
で、かつモノリス担体に塗布される触媒層固形分中５〜
６０重量％であることが好ましい。添加量がこれより少
い場合は、添加効果は認められるものの、ロジウムとの
接触が充分でないためロジウムとの相互作用が小さくな
り、本発明による触媒性能上の優位性は充分に発揮され
ない。また、添加量が上記数値より多い場合には、有意
な添加量増量効果はみられない。[0010] The amount of the oxide powder containing at least cerium and zirconium used in the present invention is more than 20 g per 1 L of the catalyst capacity and 100 g or less, and the amount of the catalyst layer applied to the monolithic carrier is not more than 20 g. 5 to 5 minutes
Preferably it is 60% by weight. When the addition amount is smaller than this, although the effect of addition is recognized, the contact with rhodium is insufficient, so that the interaction with rhodium becomes small and the superiority in catalytic performance according to the present invention is not sufficiently exhibited. When the amount of addition is larger than the above value, no significant effect of increasing the amount of addition is observed.
【００１１】[0011]
【作用】本発明の排ガス浄化用触媒に用いるセリウムと
ジルコニウムを含む酸化物粉末は、少くとも一部がジル
コニウムを主成分とする複合酸化物として存在してい
る。このセリウムとジルコニウムを含む酸化物粉末をロ
ジウムを含むコート層中に添加することにより、ロジウ
ムの持つ触媒作用が向上しその結果排ガス浄化作用が向
上する。その機構はまだ明らかとなっていないが、複合
化により酸化セリウム、酸化ジルコニウム単独では得ら
れないO2ストレージ能が発現することが判った。The oxide powder containing cerium and zirconium used in the exhaust gas purifying catalyst of the present invention exists at least partially as a composite oxide containing zirconium as a main component. By adding the oxide powder containing cerium and zirconium to the coating layer containing rhodium, the catalytic action of rhodium is improved, and as a result, the exhaust gas purifying action is improved. Although the mechanism has not been elucidated yet, it has been found that the composite exhibits an O 2 storage capacity that cannot be obtained with cerium oxide or zirconium oxide alone.
【００１２】表１に、下記反応条件でO2パルス法によ
り、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（実施例２で用いたもの）、酸化セリウム粉
末、酸化ジルコニウム粉末につき、それぞれの酸素吸収
量を測定した結果を示す。 反応条件：H2還元 ５００℃、２時間 O2パルス温度 ２０℃ 触媒量 0.2 g Table 1 shows that the oxide powder containing cerium and zirconium used in the present invention (used in Example 2), the cerium oxide powder, and the zirconium oxide powder were obtained by the O 2 pulse method under the following reaction conditions. 2 shows the results of measuring the oxygen absorption of the sample. Reaction conditions: H 2 reduction 500 ° C, 2 hours O 2 pulse temperature 20 ° C Catalyst amount 0.2 g
【００１３】表１より明らかなように、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は、酸化
セリウム粉末、酸化ジルコニウム粉末に比較し優れた酸
素吸収能力を示す。酸素吸収能力が向上することによ
り、例えば排ガス雰囲気が酸素過剰の状態でも酸素を吸
収し排ガス浄化に適した酸素濃度に保つことが可能とな
る。また、貴金属の酸化状態を排ガス浄化に適した状態
に保つ可能性もある。As is clear from Table 1, the oxide powder containing cerium and zirconium used in the present invention has an excellent oxygen absorbing ability as compared with cerium oxide powder and zirconium oxide powder. By improving the oxygen absorption capacity, for example, even if the exhaust gas atmosphere is in a state of excess oxygen, it becomes possible to absorb oxygen and maintain an oxygen concentration suitable for exhaust gas purification. Further, the oxidation state of the noble metal may be maintained in a state suitable for exhaust gas purification.
【００１４】さらに本法では、コートスラリー調整時の
配合比あるいは、スラリー塗布量によってセリウムとジ
ルコニウムを含む酸化物量を調整することが容易であ
り、自動車排ガスなど排ガス組成が酸素雰囲気と還元雰
囲気との間で変動する場合に、その使用条件に応じて添
加量を調整することが可能となっている。Further, according to the present method, it is easy to adjust the amount of oxides containing cerium and zirconium by adjusting the mixing ratio at the time of coating slurry adjustment or the amount of slurry applied. When it fluctuates between them, it is possible to adjust the amount of addition according to the use conditions.
【００１５】この様な作用効果により、本発明の排ガス
浄化用触媒は優れた排ガス浄化作用を持つ。Due to the above-mentioned effects, the exhaust gas purifying catalyst of the present invention has an excellent exhaust gas purifying effect.
【００１６】[0016]
【実施例】以下、本発明を実施例、比較例および試験例
により説明する。The present invention will be described below with reference to examples, comparative examples and test examples.
【００１７】実施例１ セリウム塩とジルコニウム塩の混合水溶液にアンモニア
水溶液を徐々に加え、生じた沈澱を濾過し焼成してセリ
ウムとジルコニウムを含む酸化物粉末を得た（Ce／Zr比
＝１／９）。また、あらかじめZrを３重量％担持し焼成
した活性アルミナ粉末に硝酸ロジウム水溶液を噴霧し焼
成してロジウム担持アルミナ粉末を得た（Rh 1.5重量
％）。上記酸化物粉末450g、ロジウム担持アルミナ粉末
450g及び酢酸10重量％水溶液900g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。このスラリー
液をコーディライト質モノリス担体（1.3 L)に噴霧し、
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、400 ℃で１時間焼成してコート層重量 80g／L −担
体の（触媒−１）を得た。 EXAMPLE 1 An aqueous ammonia solution was gradually added to a mixed aqueous solution of a cerium salt and a zirconium salt, and the resulting precipitate was filtered and calcined to obtain an oxide powder containing cerium and zirconium (Ce / Zr ratio = 1/1). 9). An activated rhodium nitrate aqueous solution was sprayed on calcined activated alumina powder which was previously loaded with 3% by weight of Zr and calcined to obtain rhodium-loaded alumina powder (Rh 1.5% by weight). 450 g of the above oxide powder, alumina powder carrying rhodium
450 g and 900 g of a 10% by weight aqueous solution of acetic acid were charged into a magnetic ball mill and mixed and pulverized to obtain a slurry liquid. This slurry liquid is sprayed on a cordierite monolithic carrier (1.3 L),
Excess slurry in the cell was removed with an air stream, dried, and calcined at 400 ° C. for 1 hour to obtain a catalyst (catalyst-1) with a coat layer weight of 80 g / L.
【００１８】実施例２ 実施例１におけるセリウムとジルコニウムを含む酸化物
粉末のCe／Zr比２／８としたものを用いた以外は実施例
１と同様の方法で（触媒−２）を得た。 Example 2 (Catalyst-2) was obtained in the same manner as in Example 1 except that the oxide powder containing cerium and zirconium used in Example 1 was changed to have a Ce / Zr ratio of 2/8. .
【００１９】実施例３ 実施例１におけるセリウムとジルコニウムを含む酸化物
粉末のCe／Zr比を３／７としたものを用いた以外は実施
例１と同様の方法で（触媒−３）を得た。 Example 3 (Catalyst-3) was obtained in the same manner as in Example 1 except that the oxide powder containing cerium and zirconium used in Example 1 had a Ce / Zr ratio of 3/7. Was.
【００２０】比較例１ 実施例１におけるセリウムとジルコニウムを含む酸化物
粉末のCe／Zr比４／６としたものを用いた以外は実施例
１と同様の方法で（触媒−４）を得た。 Comparative Example 1 (Catalyst-4) was obtained in the same manner as in Example 1 except that the oxide powder containing cerium and zirconium used in Example 1 had a Ce / Zr ratio of 4/6. .
【００２１】比較例２ 実施例１におけるセリウムとジルコニウムを含む酸化物
粉末の代わりに酸化ジルコニウムを用いた以外は実施例
１と同様の方法で（触媒−５）を得た。 Comparative Example 2 (Catalyst-5) was obtained in the same manner as in Example 1 except that zirconium oxide was used instead of the oxide powder containing cerium and zirconium in Example 1.
【００２２】比較例３ 実施例１におけるセリウムとジルコニウムを含む酸化物
粉末の代わりに酸化セリウムを用いた以外は実施例１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 1 except that cerium oxide was used instead of the oxide powder containing cerium and zirconium.
【００２３】比較例４ 実施例１におけるセリウムとジルコニウムを含む酸化物
粉末の代わりに酸化ジルコニウムに硝酸セリウム水溶液
をCe／Zr比＝１／９となるよう含浸担持し、650 ℃で１
時間焼成したものを用いた以外は実施例１と同様の方法
で（触媒−７）を得た。 Comparative Example 4 Instead of the oxide powder containing cerium and zirconium in Example 1, an aqueous cerium nitrate solution was impregnated and supported on zirconium oxide so that the Ce / Zr ratio was 1/9.
(Catalyst-7) was obtained in the same manner as in Example 1 except that the material calcined for an hour was used.
【００２４】実施例４ 実施例１と同様の製法でRhを1.0 重量％担持したロジウ
ム担持アルミナ粉末を得た。またあらかじめCeを８重量
％、Zrを４重量％、Baを４重量％担持し焼成したアルミ
ナ粉末を得、これを攪拌しながら硝酸パラジウム水溶液
を噴霧し、その後焼成してPdを1.07重量％担持したパラ
ジウム1.07重量％担持アルミナ粉末を得た。さらに同様
の方法でパラジウム1.19重量％パラジウム担持アルミナ
を得た。また硝酸ジルコニウムと硝酸セリウムを含む水
溶液にアンモニア水溶液を添加し、生成した沈澱物を焼
成して、ZrO2を10重量％含むジルコニア10重量％−セリ
ウム酸化物を得た。上記パラジウム1.19％担持アルミナ
粉末772g、上記ジルコニア10重量％−セリウム酸化物42
8g、酢酸10重量％水溶液1200g を実施例１と同様の方法
でモノリス担体（1.7 L)に担持し、コート層重量140g／
L−担体を得た。さらに上記ロジウム担持アルミナ粉末
114g、上記パラジウム1.07重量％担持アルミナ306g、実
施例２と同様のセリウムとジルコニウムを含む酸化物粉
末480g、酢酸10重量％水溶液900gを実施例１と同様の方
法で上記コート層重量140g／ L−担体に担持し、コート
層重量合計210g／ L−担体の（触媒−８）を得た。 Example 4 Rhodium-supported alumina powder supporting 1.0% by weight of Rh was obtained in the same manner as in Example 1. An alumina powder baked with 8% by weight of Ce, 4% by weight of Zr, and 4% by weight of Ba was obtained in advance, and an aqueous solution of palladium nitrate was sprayed with stirring, and then fired to carry 1.07% by weight of Pd. 1.07% by weight of palladium-supported alumina powder was obtained. Further, palladium 1.19% by weight palladium-supported alumina was obtained in the same manner. The addition of aqueous ammonia solution in an aqueous solution containing zirconium nitrate and cerium nitrate, and calcining the resulting precipitate, the ZrO 2 10 wt% zirconia 10 wt% - to obtain a cerium oxide. 772 g of alumina powder supported on 1.19% palladium, 10% by weight of zirconia-cerium oxide 42
8 g and 1200 g of a 10% by weight aqueous solution of acetic acid were supported on a monolithic carrier (1.7 L) in the same manner as in Example 1, and a coat layer weight of 140 g /
L-carrier was obtained. Further, the above rhodium-supported alumina powder
In the same manner as in Example 1, 114 g, 306 g of the above-mentioned alumina carrying 1.07% by weight of palladium, 480 g of an oxide powder containing cerium and zirconium, and 900 g of an aqueous solution of 10% by weight of acetic acid were used. (Catalyst-8) having a total of 210 g / L-carrier weight on the carrier was obtained.
【００２５】比較例５ 実施例４におけるセリウムとジルコニウムを含む酸化物
の代わりに比較例３と同様のセリウム、ジルコニウム酸
化物を用いた以外は実施例４と同様の方法で（触媒−
９）を得た。COMPARATIVE EXAMPLE 5 The same procedure as in Example 4 was repeated except that the oxide containing cerium and zirconium in Example 4 was replaced with the same cerium and zirconium oxide as in Comparative Example 3 (catalyst-
9) was obtained.
【００２６】実施例５ 実施例１と同様の方法でＲｈを１．０重量％担持したロ
ジウム担体アルミナ粉末を得た。また、あらかじめＣｅ
を８重量％、Ｚｒを４重量％、Ｌａを４重量％担持し焼
成して得たＣｅ−Ｚｒ−Ｌａ−アルミナ粉末を得、これ
を攪拌しながら硝酸パラジウム水溶液を噴霧し、その後
焼成してＰｄを１．１６重量％担持したパラジウム担体
アルミナ粉末を得た。上記パラジウム担持アルミナ粉末
７７２ｇ、実施例４と同様のジルコニア１０重量％−セ
リウム酸化物４２８ｇ、硝酸酸性アルミナゾル１２００
ｇを実施例１と同様の方法で担持し、コート層重量１４
２ｇ／Ｌ−担体を得た。さらに上記ロジウム担持アルミ
ナ粉末１１４ｇ、上記パラジウム担持アルミナ粉末２７
９ｇ、実施例２と同様のセリウムとジルコニウムを含む
酸化物粉末３８０ｇ、上記Ｃｅ−Ｚｒ−Ｌａ−アルミナ
粉末８９ｇ、硝酸酸性アルミナゾル９００ｇを、実施例
１と同様の方法で上記コート層重量１４２ｇ／Ｌ−担体
に担持し、コート層重量合計２１３ｇ／Ｌ−担体の（触
媒−１０）を得た。 Example 5 In the same manner as in Example 1, rhodium-supported alumina powder supporting 1.0% by weight of Rh was obtained. In addition, Ce
And 8% by weight of Zr, 4% by weight of Zr, and 4% by weight of La to obtain Ce-Zr-La-alumina powder, which was calcined to obtain a powder. A palladium-supported alumina powder supporting 1.16% by weight of Pd was obtained. 772 g of the above-described palladium-supported alumina powder, 10% by weight of zirconia-cerium oxide 428 g as in Example 4, and nitric acid acidic alumina sol 1200
g was carried in the same manner as in Example 1, and the coating layer weight was 14%.
2 g / L-carrier was obtained. Further, 114 g of the rhodium-supported alumina powder and 27 g of the palladium-supported alumina powder
9 g, 380 g of the same oxide powder containing cerium and zirconium as in Example 2, 89 g of the above-mentioned Ce-Zr-La-alumina powder, and 900 g of nitric acid acidic alumina sol were prepared in the same manner as in Example 1 to obtain a coat layer weight of 142 g / L. -(Catalyst-10) supported on a carrier to obtain a total of 213 g / L of a coat layer weight-carrier.
【００２７】比較例６ 実施例５におけるセリウムとジルコニウムを含む酸化物
粉末を２５４ｇ、Ｃｅ−Ｚｒ−Ｌａ−アルミナ粉末を２
１５ｇとした以外は実施例５と同様の方法で触媒を調整
し、（触媒−１１）を得た。 Comparative Example 6 254 g of the oxide powder containing cerium and zirconium in Example 5, and 2 parts of the Ce-Zr-La-alumina powder
A catalyst was prepared in the same manner as in Example 5 except that the amount was changed to 15 g, to obtain (Catalyst-11).
【００２８】比較例７ 実施例５におけるセリウムとジルコニウムを含む酸化物
粉末を１２７ｇ、Ｃｅ−Ｚｒ−Ｌａ−アルミナ粉末を３
４２ｇとした以外は実施例５と同様の方法で触媒を調整
し、（触媒−１２）を得た。 Comparative Example 7 127 g of the oxide powder containing cerium and zirconium in Example 5, and 3 g of the Ce-Zr-La-alumina powder
A catalyst was prepared in the same manner as in Example 5 except that the amount was changed to 42 g, whereby (Catalyst-12) was obtained.
【００２９】実施例６ 実施例１と同様の方法でＲｈを２．２５３重量％担持し
たロジウム担持アルミナ粉末を得た。また、あらかじめ
Ｃｅを３重量％担持し焼成したＣｅ−アルミナ粉末を
得、これを攪拌しながらジニトロジアンミン白金酸水溶
液を噴霧し、その後焼成してｐｔを１．１重量％担持し
た白金担持アルミナ粉末を得た。上記白金担持アルミナ
粉末６１１ｇ、実施例４と同様のジルコニア１０重量％
−セリウム酸化物４５３ｇ、上記Ｃｅ−アルミナ粉末４
３ｇ、硝酸酸性アルミナゾル１２００ｇを実施例１と同
様の方法で担持し、コート層重量２１０ｇ／Ｌ−担体を
得た。さらに上記ロジウム担持アルミナ粉末１７２ｇ、
上記Ｃｅ−アルミナ粉末３３１ｇ、実施例２と同様のセ
リウムとジルコニウムを含む酸化物粉末３２７ｇ、硝酸
酸性アルミナゾル９００ｇを実施例１と同様の方法で上
記コート層重量２１０ｇ／Ｌ担体に担持し、コート層重
量合計２６５ｇ／Ｌ−担体の（触媒−１３）を得た。 Example 6 In the same manner as in Example 1, rhodium-supported alumina powder supporting 2.253% by weight of Rh was obtained. In addition, a Ce-alumina powder preliminarily loaded with 3% by weight of Ce and calcined was obtained, and an aqueous solution of dinitrodiammineplatinic acid was sprayed while stirring the powder, and then calcined, followed by a platinum-loaded alumina powder loaded with 1.1% by weight of pt. I got 611 g of the above platinum-supported alumina powder, 10% by weight of zirconia as in Example 4.
453 g of cerium oxide, Ce-alumina powder 4
3 g and 1200 g of nitric acid acidic alumina sol were carried in the same manner as in Example 1 to obtain a coat layer weight of 210 g / L-carrier. Further, 172 g of the above rhodium-supported alumina powder,
331 g of the Ce-alumina powder, 327 g of the same oxide powder containing cerium and zirconium as in Example 2, and 900 g of nitric acid-alumina sol were loaded on the carrier with a coat layer weight of 210 g / L in the same manner as in Example 1. (Catalyst-13) having a total weight of 265 g / L-carrier was obtained.
【００３０】比較例８ 実施例６におけるセリウムとジルコニウムを含む酸化物
粉末の代わりに実施例５と同様のジルコニウム１０重量
％−セリウム酸化物を用いた以外は実施例６と同様の方
法で（触媒−１４）を得た。COMPARATIVE EXAMPLE 8 A catalyst was prepared in the same manner as in Example 6 except that the oxide powder containing cerium and zirconium in Example 6 was replaced with 10% by weight of zirconium-cerium oxide as in Example 5. -14).
【００３１】試験例１ 実施例１〜３および５、比較例１〜４および６〜７の各
触媒（触媒１〜７および10〜12) につき、下記条件でエ
ンジン耐久を行った後の性能評価を行い、耐久劣化触媒
のHC、CO、NOx 浄化率を測定した。 触媒性能評価結果を表２に示す。 ＜エンジン耐久条件＞ 触媒入口排ガス温度 850 ℃ 耐久時間 50 時間 エンジン 排気量 4400 CC 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1000 ppm HC 約2500 ppm 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 4400 CC 燃料 無鉛ガソリン 平均空燃比（制御中心値） 14.6 Test Example 1 Performance evaluation of the catalysts of Examples 1-3 and 5 and Comparative Examples 1-4 and 6-7 (catalysts 1-7 and 10-12) after engine durability under the following conditions: was carried out, was HC durability deteriorated catalyst, CO, and the NO x purification rate were measured. Table 2 shows the catalyst performance evaluation results. <Engine endurance conditions> Catalyst inlet exhaust gas temperature 850 ° C Endurance time 50 hours Engine Displacement 4400 CC fuel Unleaded gasoline Endurance inlet emission during endurance CO 0.4 to 0.6% O 2 0.5 ± 0.1% NO Approx. 1000 ppm HC Approx. 2500 ppm CO 2 14.9 ± 0.1% <Performance evaluation conditions> Catalyst inlet exhaust gas temperature 400 ° C Engine Engine displacement 4400 CC fuel Unleaded gasoline Average air-fuel ratio (control center value) 14.6
【００３２】試験例２ 実施例４および比較例５の触媒（触媒８〜９）につき触
媒入口ガス温度を750℃、耐久時間を 100時間とした以
外は試験例１の場合と同じ条件でエンジン耐久を行った
後の性能評価を行い、耐久劣化触媒のHC、CO、NOx 浄化
率を測定した。触媒性能評価結果を表２に示す。試験例３ 実施例６および比較例８の触媒（触媒13〜14) につき、
触媒入口ガス温度を900 ℃、燃料を有鉛ガソリンとした
以外は試験例１の場合と同じ条件でエンジン耐久を行っ
た後の性能評価を行い、耐久劣化触媒のHC、CO、NOx 浄
化率を測定した。触媒評価結果を表２に示す。 Test Example 2 The engine durability was the same as in Test Example 1, except that the catalyst inlet gas temperature was 750 ° C. and the durability time was 100 hours for the catalysts of Examples 4 and 5 (catalysts 8 to 9). It was subjected to performance evaluation after and HC durability deteriorated catalyst, CO, and the NO x purification rate were measured. Table 2 shows the catalyst performance evaluation results. Test Example 3 For the catalysts of Examples 6 and Comparative Example 8 (catalysts 13 to 14),
Performance evaluation was performed after engine durability under the same conditions as in Test Example 1 except that the catalyst inlet gas temperature was 900 ° C and the fuel was leaded gasoline, and the HC, CO, and NO x purification rates of the durability-degraded catalyst were evaluated. Was measured. Table 2 shows the catalyst evaluation results.
【００３３】[0033]
【表２】 [Table 2]
【００３４】[0034]
【発明の効果】以上説明してきたようにこの発明によれ
ば、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をロジウムを含むコート層
中に添加することにより、他のセリウムおよびジルコニ
ウム酸化物の添加に比べ、高温耐久後の排ガス浄化性能
において明らかに優れた触媒性能が得られる。これは実
施例からわかるように、排ガス浄化用触媒に用いられた
セリウムとジルコニウムを含む酸化物が、その少くとも
一部がジルコニウムを主成分とし複合化している効果に
よるものであることは明らかである。さらに、本発明の
効果はセリウムとジルコニウムを含む酸化物の添加量が
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。As described above, according to the present invention, an oxide powder containing cerium and zirconium produced by a precipitation reaction from an aqueous solution containing at least cerium and zirconium ions is coated with a rhodium-containing coat. By adding it in the layer, it is possible to obtain clearly superior catalytic performance in exhaust gas purification performance after high-temperature durability as compared with the addition of other cerium and zirconium oxides. As can be seen from the examples, it is apparent that the oxide containing cerium and zirconium used in the exhaust gas purifying catalyst is due to the effect that at least a part of the oxide contains zirconium as a main component and is complexed. is there. Further, the effect of the present invention is remarkable when the amount of the oxide containing cerium and zirconium is relatively large, and there is a suitable range for the ratio of cerium to zirconium.
Claims (7)
酸性水溶液に、アルカリ性水溶液を添加してセリウムお
よびジルコニウム含有沈殿生成物を生成し、 （２）得られたセリウムおよびジルコニウム含有沈殿生
成物を乾燥し、しかる後焼成して金属換算で１０〜３０
モル％のセリウムと７０〜９０モル％のジルコニウムを
含むセリウムおよびジルコニウム含有酸化物粉末を調製
し、 （３）得られたセリウムおよびジルコニウム含有酸化物
粉末と、ロジウム；又はロジウムおよび白金もしくはパ
ラジウムを含有する活性アルミナ粉末とを、湿式にて混
合しスラリーを調製し、次いで （４）得られたスラリーを担体に塗布し、しかる後乾燥
し、焼成する、を含んでなる、排ガス浄化用触媒の製造
方法。(1) The following steps (1) to (4): (1) An alkaline aqueous solution is added to an acidic aqueous solution containing cerium and zirconium ions to form a cerium and zirconium-containing precipitation product. 2) The obtained cerium- and zirconium-containing precipitation product is dried, and then calcined to obtain 10 to 30 in terms of metal.
Preparing a cerium and zirconium-containing oxide powder containing mol% cerium and 70-90 mol% zirconium; (3) containing the obtained cerium and zirconium-containing oxide powder and rhodium; or rhodium and platinum or palladium. And a slurry is prepared by mixing the activated alumina powder to be prepared in a wet manner, and then (4) applying the obtained slurry to a carrier, followed by drying and calcining. Method.
酸性水溶液に、アルカリ性水溶液を添加してセリウムお
よびジルコニウム含有沈殿生成物を生成し、 （２）得られたセリウムおよびジルコニウム含有沈殿生
成物を乾燥し、しかる後焼成して金属換算で１０〜３０
モル％のセリウムと７０〜９０モル％のジルコニウムを
含むセリウムおよびジルコニウム含有酸化物粉末を調製
し、 （３）得られたセリウムおよびジルコニウム含有酸化物
粉末を、湿式にて混合しスラリーを調製し、 （４）得られたスラリーを担体に塗布し、しかる後乾燥
し、焼成しセリウムおよびジルコニウムを担持した担体
を調製し、次いで （５）得られたセリウムおよびジルコニウムを担持した
担体を、ロジウム；又はロジウムおよび白金もしくはパ
ラジウムを含有する水溶液に浸漬し、乾燥しそして焼成
する、 を含んでなる排ガス浄化用触媒の製造方法。2. The following steps (1) to (5): (1) An alkaline aqueous solution is added to an acidic aqueous solution containing cerium and zirconium ions to produce a cerium and zirconium-containing precipitation product. 2) The obtained cerium- and zirconium-containing precipitation product is dried, and then calcined to obtain 10 to 30 in terms of metal.
Preparing cerium and zirconium-containing oxide powder containing cerium of 70% by mole and cerium and zirconium of 70 to 90% by mole, and (3) mixing the obtained cerium and zirconium-containing oxide powder by a wet method to prepare a slurry; (4) The obtained slurry is applied to a carrier, and then dried and calcined to prepare a carrier supporting cerium and zirconium. (5) The obtained carrier supporting cerium and zirconium is converted to rhodium; or A method for producing an exhaust gas purifying catalyst, comprising: immersing in an aqueous solution containing rhodium and platinum or palladium, drying and calcining.
特徴とする請求項１又は２記載の排ガス浄化用触媒の製
造方法。3. The method for producing an exhaust gas purifying catalyst according to claim 1, wherein the acidic aqueous solution is a nitric acid aqueous solution.
または尿素水溶液であることを特徴とする請求項１又は
２記載の排ガス浄化用触媒の製造方法。4. The method for producing an exhaust gas purifying catalyst according to claim 1, wherein the alkaline aqueous solution is an aqueous solution of ammonia and / or urea.
された排ガス浄化用触媒。5. An exhaust gas purifying catalyst produced by the production method according to claim 1.
含む酸化物粉末が、ロジウムを含むコート層中に添加さ
れていることを特徴とする請求項５記載の排ガス浄化用
触媒。6. The exhaust gas purifying catalyst according to claim 5, wherein the oxide powder containing at least cerium and zirconium is added to a coating layer containing rhodium.
含む酸化物粉末が、触媒１Ｌ当り２０ｇを超えて１００
ｇ以下、かつ、モノリス担体に塗布される触媒コート層
固形分中５〜６０重量％であることを特徴とする請求項
５記載の排ガス浄化用触媒。7. An amount of the oxide powder containing at least cerium and zirconium is more than 20 g per 1 L of the catalyst.
6. The exhaust gas purifying catalyst according to claim 5, wherein the amount is 5 to 60% by weight based on the solid content of the catalyst coat layer applied to the monolithic carrier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3133277A JP2734808B2 (en) | 1991-05-10 | 1991-05-10 | Exhaust gas purification catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3133277A JP2734808B2 (en) | 1991-05-10 | 1991-05-10 | Exhaust gas purification catalyst |
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| Publication Number | Publication Date |
|---|---|
| JPH04334548A JPH04334548A (en) | 1992-11-20 |
| JP2734808B2 true JP2734808B2 (en) | 1998-04-02 |
Family
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|---|---|---|---|
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| JP3988202B2 (en) * | 1997-04-11 | 2007-10-10 | 日産自動車株式会社 | Exhaust gas purification catalyst |
| JP4648089B2 (en) * | 2005-05-27 | 2011-03-09 | 株式会社キャタラー | Exhaust gas purification catalyst |
| JP2007105632A (en) * | 2005-10-13 | 2007-04-26 | Nissan Motor Co Ltd | Exhaust gas cleaning catalyst |
| US9403151B2 (en) | 2009-01-30 | 2016-08-02 | Umicore Ag & Co. Kg | Basic exchange for enhanced redox OS materials for emission control applications |
| BRPI0909161A2 (en) * | 2008-03-27 | 2015-11-24 | Umicore Ag & Co Kg | base metal catalysts and base metal modified diesel oxidation catalysts |
| US8778831B2 (en) | 2008-03-27 | 2014-07-15 | Umicore Ag & Co. Kg | Base metal and base metal modified diesel oxidation catalysts |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0675675B2 (en) * | 1986-11-04 | 1994-09-28 | トヨタ自動車株式会社 | Exhaust gas purification catalyst |
-
1991
- 1991-05-10 JP JP3133277A patent/JP2734808B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04334548A (en) | 1992-11-20 |
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