JPH07194973A - Exhaust gas purifying catalyst - Google Patents
Exhaust gas purifying catalystInfo
- Publication number
- JPH07194973A JPH07194973A JP6001498A JP149894A JPH07194973A JP H07194973 A JPH07194973 A JP H07194973A JP 6001498 A JP6001498 A JP 6001498A JP 149894 A JP149894 A JP 149894A JP H07194973 A JPH07194973 A JP H07194973A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- alumina
- zirconia
- purifying catalyst
- 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.)
- Pending
Links
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は過剰の酸素が存在する酸
化雰囲気中で、少量添加した炭化水素または排ガス中に
残存した炭化水素類を還元剤に用いて排ガス中の窒素酸
化物を還元除去する触媒に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces and removes nitrogen oxides in exhaust gas by using a hydrocarbon added in a small amount or hydrocarbons remaining in exhaust gas as a reducing agent in an oxidizing atmosphere in which excess oxygen exists. The present invention relates to a catalyst.
【０００２】[0002]
【従来の技術】近年、自動車，燃焼設備等において進め
られている低燃費化および排出炭酸ガスの低減化にとも
ない燃料を希薄燃焼させることが必要になってきた。こ
のため特に自動車からの排ガス浄化は従来の三元触媒を
用いることが困難となった。2. Description of the Related Art In recent years, it has become necessary to burn fuel leanly as fuel consumption is reduced and carbon dioxide emissions are reduced in automobiles and combustion equipment. For this reason, it has become difficult to use conventional three-way catalysts for purification of exhaust gas from automobiles in particular.
【０００３】このような酸素過剰の排ガス中で窒素酸化
物を還元除去するために、近年遷移金属をイオン交換し
たゼオライト触媒が有効であることが多数報告されてい
る。しかし、ゼオライトは耐熱性に問題がある。たいて
いの場合、６００℃以上の温度にさらされるとその活性
が著しく低下してしまう。そこでシリカーアルミナ比を
シリカリッチにすること、あるいはアルカリ土類金属又
は希土類元素を添加することにより低温活性を失うこと
なくゼオライトの耐熱性を改善できるという報告が多数
ある。例えば特開平4−219146 号にはシリカーアルミナ
モル比を１５以上にし、Ｂａ，Ｓｒを添加して耐熱性を
有し低温活性に優れる触媒を提供している。In recent years, many reports have been made that a zeolite catalyst ion-exchanged with a transition metal is effective for reducing and removing nitrogen oxides in exhaust gas having an excess of oxygen. However, zeolite has a problem in heat resistance. In most cases, exposure to temperatures of 600 ° C. and above significantly reduces its activity. Therefore, there are many reports that the heat resistance of zeolite can be improved without losing the low temperature activity by increasing the silica-alumina ratio to silica or adding an alkaline earth metal or a rare earth element. For example, Japanese Patent Application Laid-Open No. 4-219146 provides a catalyst having a silica-alumina molar ratio of 15 or more and adding Ba and Sr, which has heat resistance and is excellent in low-temperature activity.
【０００４】一方、アルミナなど酸化物を用い耐熱性に
優れた触媒も多数報告されているが一般に酸化物を用い
た場合は反応温度が高くまた活性が低い。この問題を解
決するために種々の金属を添加して低温高活性な触媒が
提供されている。特開平4−358525号にはコバルトアル
ミネートのような金属アルミネートが有効であることが
示されている。また、特開平4−284824 号にはアルミナ
にＰｔ，Ｓｒを添加して３００〜５００℃で活性を有し
た触媒を提供している。また、特開平4− 354536号には
アルミナにアルカリ土類金属とＡｇを添加した触媒が報
告されている。On the other hand, although many catalysts having excellent heat resistance using oxides such as alumina have been reported, generally when using oxides, the reaction temperature is high and the activity is low. To solve this problem, various metals have been added to provide a catalyst having high activity at low temperature. Japanese Patent Application Laid-Open No. 4-358525 discloses that a metal aluminate such as cobalt aluminate is effective. Further, JP-A-4-284824 provides a catalyst having activity at 300 to 500 ° C. by adding Pt and Sr to alumina. Further, JP-A-4-354536 reports a catalyst in which an alkaline earth metal and Ag are added to alumina.
【０００５】[0005]
【発明が解決しようとする課題】上記従来技術にはまだ
不十分な点がある。特開平4−219146 号のゼオライトを
用いた触媒は耐熱性を改善したとはいえ、８００℃以上
の温度で長時間さらされると活性の劣化が認められる。
また、特開平4−358525号，特開平4−284824号，特開平
4−354536 号に示されたアルミナを主体とした触媒は耐
熱性に優れるが、活性が低く４００〜５００℃で５０％
程度でありその反応温度域も非常にせまいという問題が
ある。However, there are still insufficient points in the above prior art. Although the catalyst using the zeolite of JP-A-4-219146 has improved heat resistance, its activity is deteriorated when exposed to a temperature of 800 ° C. or higher for a long time.
In addition, JP-A-4-358525, JP-A-4-284824,
The catalyst composed mainly of alumina shown in No. 4-354536 has excellent heat resistance, but its activity is low and it is 50% at 400 to 500 ° C.
However, there is a problem that the reaction temperature range is very small.
【０００６】そこで本発明の目的は酸素過剰の排ガス中
で窒素酸化物を還元除去するために耐熱性に優れかつ低
温活性を有する触媒を提供することにある。Therefore, an object of the present invention is to provide a catalyst having excellent heat resistance and low-temperature activity for reducing and removing nitrogen oxides in exhaust gas with excess oxygen.
【０００７】[0007]
【課題を解決するための手段】本発明はアルミナにジル
コニアおよび銀を添加した排ガス浄化触媒である。アル
ミナにジルコニアを添加する場合、アルミナ及びジルコ
ニア，銀の原料は特に限定はなくアルコキシド，硝酸
塩，塩化物等を用いることができ、その製造法は共沈
法，ゾルゲル法，混練法等を用いることができ、アルミ
ナとジルコニアが均一に分散していれば特に限定はな
い。また、アルミナとジルコニアが化合物を形成しても
よい。The present invention is an exhaust gas purifying catalyst in which zirconia and silver are added to alumina. When adding zirconia to alumina, the raw materials of alumina, zirconia, and silver are not particularly limited, and alkoxides, nitrates, chlorides, and the like can be used, and the manufacturing method thereof includes coprecipitation method, sol-gel method, kneading method, etc. And the alumina and zirconia are uniformly dispersed, there is no particular limitation. Further, alumina and zirconia may form a compound.
【０００８】本発明の排ガス浄化触媒はアンモニアの脱
離量が最大を示す温度が２５０℃以下となる酸強度を有
する排ガス浄化触媒であって、４００〜６００℃におけ
るＮＯｘ平均浄化率が５０％以上である。The exhaust gas purifying catalyst of the present invention is an exhaust gas purifying catalyst having an acid strength such that the temperature at which the desorption amount of ammonia becomes maximum is 250 ° C. or less, and the NOx average purification rate at 400 to 600 ° C. is 50% or more. Is.
【０００９】さらに本発明は４００〜６００℃で水を含
んだガスにおけるＮＯｘ平均浄化率が５０％以上であり
乾燥ガスを用いた場合のＮＯｘ平均浄化率に対してＮＯ
ｘ平均浄化率の減少率を２０％以下とする。Further, according to the present invention, the NOx average purification rate in the gas containing water at 400 to 600 ° C. is 50% or more, and the NOx average purification rate in the case of using the dry gas is NO.
x The reduction rate of the average purification rate is 20% or less.
【００１０】また、本発明は上記ジルコニア−アルミナ
系排ガス浄化触媒と銅イオン交換ゼオライトを積層する
ことにより作製される。Further, the present invention is produced by stacking the above zirconia-alumina type exhaust gas purifying catalyst and copper ion exchanged zeolite.
【００１１】[0011]
【作用】酸素過剰の酸化雰囲気中で炭化水素を注入し排
ガス中の窒素酸化物を除去するシステムにおいて酸化雰
囲気中での窒素酸化物の除去反応は酸素と炭化水素の反
応より炭化水素と窒素酸化物を選択的に反応させること
により達成される。アルミナを主体とした固体酸性酸化
物を用いた場合は酸素と炭化水素の反応が優先される
が、ジルコニアを添加して酸強度と調節することにより
酸素と炭化水素の反応より炭化水素と窒素酸化物を選択
的に反応させ、さらに銀を添加することにより転化率を
向上させることができる。[Function] In a system for injecting hydrocarbons in an oxygen-excessive oxidizing atmosphere to remove nitrogen oxides in exhaust gas, the reaction for removing nitrogen oxides in an oxidizing atmosphere is carried out by the reaction between hydrocarbons and nitrogen oxidation rather than by the reaction between oxygen and hydrocarbons. This is achieved by selectively reacting the products. When a solid acid oxide mainly composed of alumina is used, the reaction between oxygen and hydrocarbon is prioritized, but by adjusting the acid strength by adding zirconia, the reaction between oxygen and hydrocarbon is more effective than hydrocarbon and nitrogen oxidation. The conversion can be improved by selectively reacting the substances and adding silver.
【００１２】[0012]
【実施例】 ［実施例１］アルミニウムイソプロポキシドと硝酸ジル
コニルを所定量標量し８０℃の熱水中に加え加熱撹拌し
た後、硝酸を加えてゲル化させた。得られたゲルを乾燥
後６００℃で５時間焼成してアルミナ−ジルコニア担体
を調製した。なおアルミナに対するジルコニアの添加量
はモル比で１：２０，１：８，１：４，１：１，４：１
のものを作製した。EXAMPLES Example 1 A predetermined amount of aluminum isopropoxide and zirconyl nitrate were weighed and added to hot water at 80 ° C., and the mixture was heated and stirred, and then nitric acid was added to cause gelation. The obtained gel was dried and then calcined at 600 ° C. for 5 hours to prepare an alumina-zirconia carrier. The amount of zirconia added to alumina was 1:20, 1: 8, 1: 4, 1: 1, 4: 1 in molar ratio.
Was manufactured.
【００１３】次に作製したアルミナ−ジルコニア担体に
硝酸銀または硝酸コバルト水溶液を含浸して銀またはコ
バルト担持アルミナ−ジルコニア触媒を作製した。なお
銀とコバルトはいずれの場合においても添加量を２ｗｔ
％とした。Next, the prepared alumina-zirconia carrier was impregnated with an aqueous solution of silver nitrate or cobalt nitrate to prepare a silver- or cobalt-supported alumina-zirconia catalyst. In both cases silver and cobalt are added in an amount of 2 wt.
%.
【００１４】以上の触媒を用いてアンモニアを用いた昇
温脱離法（ＴＰＤ）による酸強度測定と窒素酸化物の除
去反応試験を行った。反応試験は触媒を１０〜２０メッ
シュに粉砕，整粒したもの３ccを内径２０mmの石英製反
応管に充填して行った。また、反応ガスは窒素バランス
で以下に示した組成を用いて、３ｌ／min の流速で触媒
層に送りこんだ。The acid strength was measured by the temperature programmed desorption method (TPD) using ammonia and the nitrogen oxide removal reaction test using the above catalyst. The reaction test was carried out by filling 3 cc of a catalyst pulverized into 10 to 20 mesh and sized, into a quartz reaction tube having an inner diameter of 20 mm. The reaction gas was sent to the catalyst layer at a flow rate of 3 l / min using the composition shown below in a nitrogen balance.
【００１５】反応ガス組成 ＮＯ １０００ppm Ｏ2 １０％ Ｃ3Ｈ6 １０００ppm Ｈ2Ｏ ０または１０％ ＳＶ ６００００１／ｈ 図１には各触媒の反応試験結果を示した。なおＮＯｘの
転化率は４００〜600℃における平均浄化率で示した。
すべての触媒が水０％で５０％以上の平均浄化率を示し
たが、水１０％添加した場合は銀を担持した触媒のみ５
０％以上の平均浄化率を維持することができた。また、
ジルコニアを添加することにより水添加による平均浄化
率の低下を防いでおり、その減少率は２０％以下であり
耐水性に優れた触媒であるといえる。すなわちジルコニ
アの添加により銀担持アルミナ触媒の耐水性を改善でき
たといえる。なおジルコニアの添加量は図１の結果より
１：８〜４：１が有効である。また、図２にアンモニア
ＴＰＤの結果を示した。ジルコニアを添加することによ
り脱離温度が低温化しており酸強度が低下したことがわ
かる。Reaction gas composition NO 1000 ppm O 2 10% C 3 H 6 1000 ppm H 2 O 0 or 10% SV 600001 / h FIG. 1 shows the reaction test results of each catalyst. The NOx conversion rate is shown as the average purification rate at 400 to 600 ° C.
All the catalysts showed an average purification rate of 50% or more with 0% water, but when 10% water was added, only the catalyst supporting silver 5
The average purification rate of 0% or more could be maintained. Also,
The addition of zirconia prevents a decrease in the average purification rate due to the addition of water, and the reduction rate is 20% or less, which means that the catalyst has excellent water resistance. That is, it can be said that the addition of zirconia improved the water resistance of the silver-supported alumina catalyst. It should be noted that the effective amount of zirconia added is 1: 8 to 4: 1 based on the results shown in FIG. Moreover, the result of ammonia TPD is shown in FIG. It can be seen that the desorption temperature was lowered and the acid strength was lowered by adding zirconia.
【００１６】ジルコニア添加により耐水性を改善できる
ことがわかったが、さらに平均浄化率を大きくするため
に、銀担持アルミナ−ジルコニア触媒に塩基性酸化物を
添加することも有効である。添加する塩基性酸化物とし
てはＬａ，Ｋ，Ｃａ，Ｂａ，Ｍｇ，Ｓｒ等が挙げられ
る。塩基性酸化物を添加することによりアルミナ−ジル
コニアの酸強度を適度に調節することができる。その添
加量はアルミナ−ジルコニア担体の酸強度に依存する。
すなわちアルミナ−ジルコニアが強い酸を有する場合塩
基性酸化物の添加量が多くなり、逆にアルミナ−ジルコ
ニアが弱い酸を有する場合塩基性酸化物の添加量は少な
くなる。It was found that the water resistance can be improved by adding zirconia, but it is also effective to add a basic oxide to the silver-supported alumina-zirconia catalyst in order to further increase the average purification rate. Examples of the basic oxide to be added include La, K, Ca, Ba, Mg and Sr. By adding a basic oxide, the acid strength of alumina-zirconia can be adjusted appropriately. The amount added depends on the acid strength of the alumina-zirconia carrier.
That is, when alumina-zirconia has a strong acid, the amount of basic oxide added is large, and conversely, when alumina-zirconia has a weak acid, the amount of basic oxide added is small.
【００１７】また、酸の種類についていえばルイス酸か
ブレンステッド酸であるかにより触媒の反応活性に差が
生じる。耐水性に優れた触媒であるためにはブレンステ
ッド酸が多い方が有効である。ピリジン吸着後の触媒の
赤外吸収スペクトルを測定して見るとジルコニアを添加
するほどブレンステッド酸が多くなっていた。ジルコニ
アばかりでなくアルミナに添加することによりブレンス
テッド酸を発現できる元素を更に添加することも有効で
ありＳｉ，Ｔｉ，Ｚｎ，Ｍｏ，Ｎｂ、等の添加が有効で
ある。Regarding the type of acid, there is a difference in the reaction activity of the catalyst depending on whether it is a Lewis acid or a Bronsted acid. In order to obtain a catalyst having excellent water resistance, it is effective to use a large amount of Bronsted acid. When the infrared absorption spectrum of the catalyst after adsorption of pyridine was measured and observed, the amount of Bronsted acid increased as zirconia was added. It is effective to add not only zirconia but also an element capable of expressing Bronsted acid by adding to alumina, and addition of Si, Ti, Zn, Mo, Nb, etc. is effective.
【００１８】さらに活性成分である銀についていえばそ
の担持量が１〜３ｗｔ％のとき高い転化率と優れた耐水
性を示している。添加量を多くすることにより銀の粒子
径も変化することから、有効な銀の粒子径は５〜２５ｎ
ｍとなる。また金属成分は銀のみ示したが貴金属を添加
することも有効である。Ｐｔ，Ｒｈ，Ｐｄ，Ｒｕ，Ｉｒ
等を添加することができる。添加した貴金属もまた銀と
同様に有効な粒子径の範囲がある。As for the active ingredient silver, when the amount of silver supported is 1 to 3% by weight, high conversion and excellent water resistance are exhibited. Since the particle size of silver also changes by increasing the addition amount, the effective silver particle size is 5 to 25n.
m. Although only silver is shown as the metal component, it is effective to add a noble metal. Pt, Rh, Pd, Ru, Ir
Etc. can be added. The added noble metal also has a range of effective particle size like silver.
【００１９】［実施例２］実施例１で作製した銀担持ア
ルミナ−ジルコニア触媒（ジルコニア：アルミナ＝１：
１）１と銅イオン交換ゼオライト２を図３のように反応
管３中に積層し実施例１と同様な反応試験を行った。な
お、水は１０％加えて行った。その結果を図４に示し
た。２種類の触媒を積層することにより３００〜６００
℃の間で幅広く高い活性を示し、その平均浄化率は６３
％という結果を得た。アルミナ−ジルコニア触媒は４０
０〜６００℃で高活性であるが４００℃以下ではそれほ
ど有効でない。これに対しゼオライト系触媒は３００〜
５００℃で高活性でありこれらを積層することにより幅
広い温度域で有効な触媒を作製することができる。この
実施例では銅イオン交換ＺＳＭ−５を用いて行ったが、
３００〜５００℃で高活性な触媒であればどの様な触媒
を用いてもよい。モルデナイト，Ｘ型，Ｙ型等のゼオラ
イトに種々の金属イオン例えばＣｕ，Ｎｉ，Ｃｏ，Ｒ
ｈ，Ｐｔ等をイオン交換した触媒あるいはアルミナ系の
酸化物担体に貴金属を担持した触媒も用いることができ
た。Example 2 The silver-supported alumina-zirconia catalyst produced in Example 1 (zirconia: alumina = 1: 1)
1) 1 and copper ion-exchanged zeolite 2 were laminated in a reaction tube 3 as shown in FIG. 3, and the same reaction test as in Example 1 was conducted. Water was added at 10%. The results are shown in Fig. 4. 300-600 by stacking two types of catalysts
It exhibits a wide range of high activity between ℃ and its average purification rate is 63.
I got a result of%. Alumina-zirconia catalyst is 40
It is highly active at 0-600 ° C, but not so effective at 400 ° C or lower. On the other hand, zeolite-based catalysts
It is highly active at 500 ° C., and by stacking these, a catalyst effective in a wide temperature range can be produced. In this example, copper ion exchange ZSM-5 was used.
Any catalyst may be used as long as it is highly active at 300 to 500 ° C. Various metal ions such as Cu, Ni, Co, R in mordenite, X-type, Y-type zeolite, etc.
A catalyst in which h, Pt, etc. were ion-exchanged or a catalyst in which a noble metal was supported on an alumina-based oxide carrier could also be used.
【００２０】[0020]
【発明の効果】本発明によりＮＯｘとハイドロカーボン
を含む排ガスの排ガス浄化において高い浄化率を得るこ
とができ、更に水により阻害されることがない耐水性に
優れた触媒を提供することができる。According to the present invention, a high purification rate can be obtained in the exhaust gas purification of exhaust gas containing NOx and hydrocarbons, and a catalyst excellent in water resistance which is not hindered by water can be provided.
【図１】各触媒の平均ＮＯｘ転化率。FIG. 1 is an average NOx conversion rate of each catalyst.
【図２】アンモニアＴＰＤ結果。FIG. 2. Ammonia TPD results.
【図３】積層触媒の構成図。FIG. 3 is a configuration diagram of a laminated catalyst.
【図４】積層触媒の活性試験結果。FIG. 4 shows the activity test results of the laminated catalyst.
１…銀担持ジルコニア−アルミナ触媒、２…Ｃｕイオン
交換ゼオライト触媒、３…反応管、４…銀担持ジルコニ
ア−アルミナ‖Ｃｕイオン交換ゼオライト積層触媒。1 ... Silver-supported zirconia-alumina catalyst, 2 ... Cu ion-exchanged zeolite catalyst, 3 ... Reaction tube, 4 ... Silver-supported zirconia-alumina / Cu ion-exchanged zeolite layered catalyst.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０１Ｊ 23/50 ＺＡＢ Ａ 29/068 ＺＡＢ Ａ Ｂ０１Ｄ 53/36 １０４ Ａ (72)発明者 高橋 研 茨城県日立市大みか町七丁目１番１号 株 式会社日立製作所日立研究所内 (72)発明者 加藤 明 茨城県日立市大みか町七丁目１番１号 株 式会社日立製作所日立研究所内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location B01J 23/50 ZAB A 29/068 ZAB A B01D 53/36 104 A (72) Inventor Takahashi Ken Ibaraki Hitachi 1-1, Omika-cho, Hitachi, Ltd. In Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Akira Kato 7-1-1, Omika-cho, Hitachi, Ibaraki Hitachi, Ltd., Hitachi Research Laboratory
Claims (5)
排ガス浄化触媒において少なくともアルミナ，ジルコニ
アおよび銀を含むことを特徴とする排ガス浄化触媒。1. An exhaust gas purification catalyst for exhaust gas containing NOx and hydrocarbons, which contains at least alumina, zirconia and silver.
ンモニアの脱離量が最大を示す温度が２５０℃以下とな
る酸強度を有することを特徴とする排ガス浄化触媒。2. The exhaust gas purifying catalyst according to claim 1, wherein the exhaust gas purifying catalyst has an acid strength such that the temperature at which the amount of desorbed ammonia is maximum becomes 250 ° C. or less.
て４００〜６００℃におけるＮＯｘ平均浄化率が５０％
以上であることを特徴とする排ガス浄化触媒。3. The NOx average purification rate at 400 to 600 ° C. in the exhaust gas purification catalyst according to claim 1 or 2 is 50%.
An exhaust gas purifying catalyst having the above characteristics.
て４００〜６００℃で水を含んだガスにおけるＮＯｘ平
均浄化率が５０％以上であり乾燥ガスを用いた場合のＮ
Ｏｘ平均浄化率に対してＮＯｘ平均浄化率の減少率が２
０％以下であることを特徴とする排ガス浄化触媒。4. The exhaust gas purifying catalyst according to any one of claims 1 to 3, wherein the NOx average purification rate in a gas containing water at 400 to 600 ° C. is 50% or more, and N in the case of using a dry gas.
The reduction rate of the NOx average purification rate is 2 with respect to the Ox average purification rate.
An exhaust gas purifying catalyst, which is 0% or less.
オン交換ゼオライトを積層したことを特徴とする排ガス
浄化触媒。5. An exhaust gas purifying catalyst, characterized in that the exhaust gas purifying catalyst according to any one of claims 1 to 4 and a copper ion-exchanged zeolite are laminated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6001498A JPH07194973A (en) | 1994-01-12 | 1994-01-12 | Exhaust gas purifying catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6001498A JPH07194973A (en) | 1994-01-12 | 1994-01-12 | Exhaust gas purifying catalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07194973A true JPH07194973A (en) | 1995-08-01 |
Family
ID=11503134
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6001498A Pending JPH07194973A (en) | 1994-01-12 | 1994-01-12 | Exhaust gas purifying catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07194973A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07284664A (en) * | 1994-04-20 | 1995-10-31 | Riken Corp | Waste gas purification material and method for purifying waste gas |
| JP2003020227A (en) * | 2001-07-02 | 2003-01-24 | Toyota Central Res & Dev Lab Inc | Fine mixed oxide powder, production method thereor and catalyst |
| JP2006341152A (en) * | 2005-06-07 | 2006-12-21 | Toyota Motor Corp | Catalyst carrier manufacturing method and manufacturing method of exhaust gas purifying catalyst |
| US7743602B2 (en) | 2005-06-21 | 2010-06-29 | Exxonmobil Research And Engineering Co. | Reformer assisted lean NOx catalyst aftertreatment system and method |
| US7803338B2 (en) | 2005-06-21 | 2010-09-28 | Exonmobil Research And Engineering Company | Method and apparatus for combination catalyst for reduction of NOx in combustion products |
| US12055083B2 (en) | 2018-08-27 | 2024-08-06 | Basf Corporation | Base metal doped zirconium oxide catalyst support materials |
-
1994
- 1994-01-12 JP JP6001498A patent/JPH07194973A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07284664A (en) * | 1994-04-20 | 1995-10-31 | Riken Corp | Waste gas purification material and method for purifying waste gas |
| JP2003020227A (en) * | 2001-07-02 | 2003-01-24 | Toyota Central Res & Dev Lab Inc | Fine mixed oxide powder, production method thereor and catalyst |
| JP2006341152A (en) * | 2005-06-07 | 2006-12-21 | Toyota Motor Corp | Catalyst carrier manufacturing method and manufacturing method of exhaust gas purifying catalyst |
| US7743602B2 (en) | 2005-06-21 | 2010-06-29 | Exxonmobil Research And Engineering Co. | Reformer assisted lean NOx catalyst aftertreatment system and method |
| US7803338B2 (en) | 2005-06-21 | 2010-09-28 | Exonmobil Research And Engineering Company | Method and apparatus for combination catalyst for reduction of NOx in combustion products |
| US12055083B2 (en) | 2018-08-27 | 2024-08-06 | Basf Corporation | Base metal doped zirconium oxide catalyst support materials |
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