JPH09141102A - Oxide catalyst material for removing nitrogen oxide and removal of nitrogen oxide - Google Patents
Oxide catalyst material for removing nitrogen oxide and removal of nitrogen oxideInfo
- Publication number
- JPH09141102A JPH09141102A JP7304686A JP30468695A JPH09141102A JP H09141102 A JPH09141102 A JP H09141102A JP 7304686 A JP7304686 A JP 7304686A JP 30468695 A JP30468695 A JP 30468695A JP H09141102 A JPH09141102 A JP H09141102A
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- Japan
- Prior art keywords
- nitrogen oxides
- oxide
- catalyst material
- weight
- oxide catalyst
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、窒素酸化物を還元
除去することができる新規な酸化物触媒材料並びにこれ
を用いて排気ガス中の窒素酸化物を除去する方法に関す
るもので、とりわけ排気ガス温度が低いディーゼルエン
ジン等の自動車排気ガス浄化用として好適な窒素酸化物
除去用酸化物触媒材料並びに該酸化物触媒材料を用いて
低温で排気ガス中の窒素酸化物を除去する方法に関する
ものである。TECHNICAL FIELD The present invention relates to a novel oxide catalyst material capable of reducing and removing nitrogen oxides and a method for removing nitrogen oxides in exhaust gas using the same, and more particularly to exhaust gas. The present invention relates to an oxide catalyst material for removing nitrogen oxides suitable for purifying automobile exhaust gas such as diesel engine having a low temperature, and a method for removing nitrogen oxides in exhaust gas at low temperature using the oxide catalyst material. .
【０００２】[0002]
【従来の技術】近年、各種汚染物質による大気の汚れが
大きな社会問題となり、その中でも大気汚染の移動発生
源となっている自動車の排気ガスに含まれるＮＯｘ、Ｃ
Ｏｘ等の有害物質を分解、除去する方法の開発が急務と
なっている。2. Description of the Related Art In recent years, air pollution caused by various pollutants has become a major social problem, and among them, NOx and C contained in exhaust gas of automobiles, which are sources of migration of air pollution.
There is an urgent need to develop a method for decomposing and removing harmful substances such as Ox.
【０００３】従来より、自動車の排気ガス中のＮＯｘ、
ＣＯｘ等の有害物質を分解、除去する方法としては、一
酸化炭素（ＣＯ）および炭化水素（ＣｘＨｙ）の酸化
と、窒素酸化物（ＮＯｘ）の還元を同時に行う三元触媒
が汎用されてきた。Conventionally, NOx in exhaust gas of automobiles,
As a method of decomposing and removing harmful substances such as COx, a three-way catalyst that simultaneously oxidizes carbon monoxide (CO) and hydrocarbons (CxHy) and reduces nitrogen oxides (NOx) has been widely used.
【０００４】そのような方法に用いられる三元触媒とし
ては、パラジウム（Ｐｄ）、白金（Ｐｔ）、ロジウム
（Ｒｈ）等の貴金属を、γ−アルミナ（Ａｌ2 Ｏ3 ）で
被覆したコージェライト等の耐火性担体に担持したもの
が用いられていた。Examples of the three-way catalyst used in such a method include cordierite in which a noble metal such as palladium (Pd), platinum (Pt), and rhodium (Rh) is coated with γ-alumina (Al 2 O 3 ). Supported on a refractory carrier.
【０００５】しかしながら、前記三元触媒は、およそ
０．５％程度の低酸素濃度においては排気ガスの浄化を
効率良く行うことができるものの、排気ガス中の酸素濃
度が１％を越えるような高濃度雰囲気中では有効に働か
ないという欠点があった。However, the three-way catalyst can efficiently purify the exhaust gas at a low oxygen concentration of about 0.5%, but has a high oxygen concentration in the exhaust gas exceeding 1%. There is a disadvantage that it does not work effectively in a concentration atmosphere.
【０００６】一方、前記欠点を回避するため、排気ガス
中の酸素濃度を測定し、常にＣＯ及びＣｘＨｙ、ＮＯｘ
を高い浄化率で処理し得る理論当量値に近い範囲の空燃
比となるように制御することも行われているが、前記Ｃ
Ｏ及びＣｘＨｙとＮＯｘの発生メカニズムが相反する特
性を有することから、限られた状態での燃焼を維持しな
ければならず、前記のような高い酸素濃度中での排気ガ
ス浄化はほとんどできていないのが現状である。On the other hand, in order to avoid the above-mentioned drawbacks, the oxygen concentration in the exhaust gas is measured, and CO, CxHy and NOx are constantly measured.
Is controlled so as to have an air-fuel ratio in a range close to a stoichiometric equivalent value that can be processed at a high purification rate.
Since the generation mechanisms of O, CxHy, and NOx have contradictory characteristics, it is necessary to maintain combustion in a limited state, and exhaust gas purification in the high oxygen concentration as described above is hardly achieved. is the current situation.
【０００７】そこで、係る高濃度の酸素共存下でもＮＯ
ｘを効率よく除去できる触媒として、金属を担持した疎
水性ゼオライト等の銅イオン交換ゼオライト、あるいは
メタルシリケート、アルミナ触媒等が提案されている
（特開平４−３４９９３８号公報参照）。Therefore, even in the presence of such a high concentration of oxygen, NO
As a catalyst capable of efficiently removing x, a copper ion-exchanged zeolite such as a hydrophobic zeolite carrying a metal, a metal silicate, an alumina catalyst or the like has been proposed (see Japanese Patent Laid-Open No. 4-349938).
【０００８】[0008]
【発明が解決しようとする課題】しかしながら、前記提
案の銅イオン交換ゼオライトやメタルシリケート、ある
いはアルミナ触媒等は、いずれも耐熱性に劣るため、長
時間運転での構造破壊による性能劣化、あるいは耐ＳＶ
（空間速度）性が悪く、排気ガスの流速が高速を示す実
際のエンジン排気ガスの条件下では、ＮＯ還元分解能が
著しく低下するという課題がある。However, the above-mentioned proposed copper ion-exchanged zeolite, metal silicate, alumina catalyst, etc. are all inferior in heat resistance, so that performance deterioration due to structural destruction during long-term operation or SV resistance.
There is a problem that the NO reduction resolution is significantly reduced under the actual engine exhaust gas conditions in which the (space velocity) property is poor and the exhaust gas flow velocity is high.
【０００９】一方、自動車排気ガス浄化用触媒として
は、耐熱性に優れ、かつ実際の自動車排気ガスの温度が
２００〜３５０℃であることから、ＮＯｘ除去率が最大
を示す作動温度範囲が、従来より更に低温域の３００〜
３５０℃近辺でも使用可能である触媒材料が要求される
ようになっており、そのままでは効果的なＮＯｘ浄化が
難しいという課題があった。On the other hand, as an automobile exhaust gas purifying catalyst, since the heat resistance is excellent and the actual automobile exhaust gas temperature is 200 to 350 ° C., the operating temperature range where the NOx removal rate is the maximum is the conventional one. Even lower temperature 300 ~
A catalyst material that can be used even at around 350 ° C. is required, and there is a problem that effective NOx purification is difficult as it is.
【００１０】[0010]
【発明の目的】本発明は、ディーゼルエンジンをはじめ
とする各種自動車用エンジン等の水分を含む酸素濃度の
高い排気ガスを、該排気ガスの流速が高速であっても、
３００℃近辺の低温度域で高いＮＯｘ還元分解作用を示
し、有効に排気ガス中のＮＯｘを浄化することができる
触媒材料並びにそれを用いた窒素酸化物除去方法を提供
するものである。It is an object of the present invention to provide exhaust gas having a high oxygen concentration containing water, such as diesel engine and various automobile engines, even if the flow velocity of the exhaust gas is high.
It is intended to provide a catalyst material which exhibits a high NOx reducing decomposition action in a low temperature range around 300 ° C. and can effectively purify NOx in exhaust gas, and a nitrogen oxide removing method using the same.
【００１１】[0011]
【課題を解決するための手段】本発明は、上記課題に鑑
みなされたもので、ＮｉおよびＧａを主たる金属元素と
して含有するスピネル型結晶性複合酸化物に、Ｃｏ、Ｎ
ｉ、Ｆｅ、Ｃｕの遷移金属から選ばれる少なくとも１種
を担持したＣｅＯ2 を添加した触媒材料が、高酸素濃度
雰囲気下でも高い触媒活性を長期にわたり有し、しかも
３００℃という低温度でも高いＮＯｘ還元分解作用を示
して有効に排気ガス中のＮＯｘを浄化することができる
ことを見出したものである。The present invention has been made in view of the above problems, and a spinel-type crystalline complex oxide containing Ni and Ga as main metal elements is added to Co and N.
The catalytic material added with CeO 2 supporting at least one selected from transition metals of i, Fe and Cu has a high catalytic activity for a long time even in a high oxygen concentration atmosphere, and has a high NOx even at a low temperature of 300 ° C. It was discovered that NOx in the exhaust gas can be effectively purified by exhibiting a reducing decomposition action.
【００１２】即ち、本発明の窒素酸化物除去用酸化物触
媒材料は、ＮｉおよびＧａを主たる金属元素として含有
するスピネル型構造を有する複合酸化物に、Ｃｏ、Ｎ
ｉ、Ｆｅ、Ｃｕの遷移金属から選ばれる少なくとも１種
を、望ましくはＣｏ及びＮｉでは０．１〜２０重量％、
Ｆｅでは１〜２０重量％、Ｃｕでは０．１〜５重量％を
担持したＣｅＯ2 を５〜７５重量％添加して成る触媒材
料である。That is, the oxide catalyst material for removing nitrogen oxides according to the present invention is a composite oxide having a spinel type structure containing Ni and Ga as main metal elements, Co, N.
i, Fe, at least one selected from transition metals of Cu, preferably 0.1 to 20% by weight for Co and Ni,
It is a catalyst material obtained by adding 5 to 75% by weight of CeO 2 supporting 1 to 20% by weight of Fe and 0.1 to 5% by weight of Cu.
【００１３】特に、前記遷移金属から選ばれる少なくと
も１種をＣｏ及びＮｉの場合には０．５〜１０重量％、
Ｆｅでは１．０〜１０重量％、Ｃｕでは０．１〜３重量
％担持したＣｅＯ2 を、スピネル型複合酸化物に１０〜
５０重量％添加した酸化物触媒材料であることがより好
ましく、とりわけ前記遷移金属から選ばれる少なくとも
１種をＣｏの場合では０．５〜５重量％、Ｎｉでは１〜
１０重量％、Ｆｅでは２〜１０重量％、Ｃｕの場合には
０．１〜１重量％担持したＣｅＯ2 を、スピネル型複合
酸化物に１０〜４０重量％添加した酸化物触媒材料が最
も好ましい。In particular, in the case of Co and Ni, at least one selected from the above transition metals is 0.5 to 10% by weight,
In Fe 1.0 to 10 wt%, the CeO 2 which is 0.1 to 3 wt% on the Cu,. 10 to the spinel-type composite oxide
It is more preferable to use an oxide catalyst material added with 50% by weight, particularly 0.5 to 5% by weight in the case of Co, and 1 to 5 in the case of Ni, at least one selected from the transition metals.
Most preferred is an oxide catalyst material obtained by adding 10 to 40% by weight of CeO 2 loaded with 10% by weight, 2 to 10% by weight of Fe, and 0.1 to 1% by weight of Cu. .
【００１４】更に、本発明の窒素酸化物除去方法は、高
濃度の酸素と還元性を有する炭素含有ガスが存在する酸
化雰囲気中で、ニッケル（Ｎｉ）とガリウム（Ｇａ）を
主たる金属元素として含有する結晶相がスピネル型構造
である複合酸化物に、Ｃｏ、Ｎｉ、Ｆｅ、Ｃｕ等の遷移
金属から選ばれる少なくとも１種を、望ましくはＣｏ及
びＮｉは０．１〜２０重量％、Ｆｅは１〜２０重量％、
Ｃｕについては０．１〜５重量％担持したＣｅＯ2 を５
〜７５重量％添加して成る触媒材料と窒素酸化物を含む
排気ガスとを接触させることを特徴とするものである。Further, the method for removing nitrogen oxides of the present invention contains nickel (Ni) and gallium (Ga) as main metal elements in an oxidizing atmosphere in which a high concentration of oxygen and a carbon-containing gas having a reducing property are present. In the complex oxide having a spinel structure as the crystal phase, at least one selected from transition metals such as Co, Ni, Fe, and Cu is desirably used, and Co and Ni are 0.1 to 20% by weight, and Fe is 1 ~ 20% by weight,
For Cu, 0.1% to 5% by weight of CeO 2 supported is used.
It is characterized in that the catalyst material formed by adding about 75% by weight and the exhaust gas containing nitrogen oxide are brought into contact with each other.
【００１５】なかでも、前記酸化物触媒として前記遷移
金属から選ばれる少なくとも１種をＣｏ及びＮｉについ
ては０．５〜１０重量％、Ｆｅについては１〜１０重量
％、Ｃｕについては０．１〜３重量％担持したＣｅＯ2
を、スピネル型複合酸化物に１０〜５０重量％添加した
酸化物触媒材料用いることがより望ましく、特に前記遷
移金属から選ばれる少なくとも１種をＣｏについては
０．５〜５重量％、Ｎｉについては１〜１０重量％、Ｆ
ｅについては２〜１０重量％、Ｃｕについては０．１〜
１重量％担持したＣｅＯ2 を、スピネル型複合酸化物に
１０〜４０重量％添加した酸化物触媒材料を用いること
が最も好ましい。Among them, at least one selected from the above transition metals as the oxide catalyst is 0.5 to 10% by weight for Co and Ni, 1 to 10% by weight for Fe, and 0.1 to 10% for Cu. CeO 2 loaded with 3% by weight
It is more preferable to use an oxide catalyst material obtained by adding 10 to 50% by weight to a spinel type composite oxide, and particularly 0.5 to 5% by weight for Co and 0.5 to 5% by weight for Ni for at least one selected from the above transition metals. 1-10% by weight, F
2 to 10% by weight for e, 0.1 to 0.1% for Cu
It is most preferable to use an oxide catalyst material obtained by adding 1% by weight of CeO 2 to the spinel type composite oxide in an amount of 10 to 40% by weight.
【００１６】本発明において、窒素酸化物除去用酸化物
触媒材料として、先ず、ＣｅＯ2 に担持するＣｏ、Ｎ
ｉ、Ｆｅ、Ｃｕの遷移金属の少なくとも１種がＣｏ、Ｎ
ｉ、Ｃｕの場合には０．１重量％未満、Ｆｅの場合では
１重量％未満の場合には、３００℃近辺での触媒活性の
向上効果が少なく、逆に、Ｃｏ、Ｎｉ、Ｆｅの場合では
２０重量％を越える場合、Ｃｕでは５重量％を越える場
合には低温度域での触媒活性がそれほど大きくないこと
から、Ｃｏ及びＮｉについては０．１〜２０重量％、Ｆ
ｅについては１〜２０重量％、Ｃｕについては０．１〜
５重量％が望ましく、特に前記活性温度域が広いという
観点からはＣｏ及びＮｉについては０．５〜１０重量
％、Ｆｅについては１〜１０重量％、Ｃｕについては
０．１〜３重量％がより好ましく、更にＮＯ除去率の最
大値が高いという点からはＣｏについては０．５〜５重
量％、Ｎｉについては１〜１０重量％、Ｆｅについては
２〜１０重量％、Ｃｕについては０．１〜１重量％が最
も望ましい傾向を示す。In the present invention, as an oxide catalyst material for removing nitrogen oxides, first, Co and N supported on CeO 2 are used.
At least one transition metal of i, Fe, and Cu is Co, N
In the case of i and Cu, less than 0.1% by weight, and in the case of Fe less than 1% by weight, the catalytic activity improving effect at around 300 ° C. is small, and conversely, in the case of Co, Ni and Fe. In the case of exceeding 20% by weight, and in the case of exceeding 5% by weight of Cu, the catalytic activity in the low temperature region is not so large.
1 to 20% by weight for e, 0.1 to 0.1% for Cu
5% by weight is desirable, and particularly from the viewpoint that the activation temperature range is wide, 0.5 to 10% by weight for Co and Ni, 1 to 10% by weight for Fe, and 0.1 to 3% by weight for Cu. More preferably, 0.5 to 5% by weight of Co, 1 to 10% by weight of Ni, 2 to 10% by weight of Fe, and 0. 1 to 1% by weight shows the most desirable tendency.
【００１７】一方、前記所定量の遷移金属の少なくとも
一種を担持したＣｅＯ2 の量が５％未満の場合には、３
００℃近辺での触媒活性の向上効果が望めず、逆に、７
５重量％を越えると前記同様であっても触媒活性が低い
ことから、その量は５〜７５重量％に特定され、特に前
記活性温度域の点では１０〜５０％重量％が好ましく、
更にＮＯ除去率の最大値の点からは１０〜４０重量％が
最も望ましい。On the other hand, when the amount of CeO 2 carrying at least one kind of the above-mentioned predetermined amount of transition metal is less than 5%, 3
The effect of improving the catalytic activity at around 00 ° C cannot be expected, and conversely, 7
If it exceeds 5% by weight, the catalytic activity is low even if it is similar to the above, so the amount is specified to be 5 to 75% by weight, and particularly 10 to 50% by weight in terms of the activation temperature range,
Further, from the viewpoint of the maximum value of NO removal rate, 10 to 40% by weight is most desirable.
【００１８】また、前記スピネル型複合酸化物は、ＮＯ
ｘを含有する排気ガスと接触させることにより、排気ガ
ス中に含まれる酸素濃度が３％以上の高濃度であって
も、その上、水蒸気が存在する雰囲気下であっても、広
い温度範囲で優れたＮＯｘ還元性能を有するものであ
る。The spinel type composite oxide is NO
By contacting with the exhaust gas containing x, even if the oxygen concentration contained in the exhaust gas is as high as 3% or more, and in addition, in an atmosphere where water vapor is present, a wide temperature range can be obtained. It has excellent NOx reduction performance.
【００１９】更に、前記排気ガス雰囲気中に、還元剤と
してＣ2 Ｈ4 、Ｃ3 Ｈ6 、Ｃ3 Ｈ8等の炭化水素、ＣＨ
3 ＯＨ、Ｃ2 Ｈ5 ＯＨ等のアルコール、ＣＯ等の還元性
を有する炭素含有ガス等を混在させて、前記複合酸化物
とＣｅＯ2 を添加してなる触媒材料を接触させると、Ｎ
Ｏｘ還元性能は更に高くなる。Further, in the exhaust gas atmosphere, hydrocarbons such as C 2 H 4 , C 3 H 6 and C 3 H 8 as a reducing agent, CH
When an alcohol such as 3 OH or C 2 H 5 OH or a carbon-containing gas having a reducing property such as CO is mixed and brought into contact with the catalyst material obtained by adding the composite oxide and CeO 2 ,
Ox reduction performance is further enhanced.
【００２０】尚、前記複合酸化物は、主たる金属元素と
してＮｉとＧａを含有し、Ｇａ／Ｎｉの原子比ｎが、
２．５〜３．３の比率からなるスピネル型複合酸化物で
あり、ＮｉＧａn Ｏ4+z （但し、ｎ＝２．５〜３．５）
の一般式で表されるものであり、前記式中の（Ｏ4+z ）
は複合酸化物として安定に存在するために必要な酸素量
であり、該酸素量は前記ｎの値により０．２以下の範囲
で随時変化するものである。The composite oxide contains Ni and Ga as main metal elements, and the Ga / Ni atomic ratio n is
A spinel composite oxide consisting of the ratio of 2.5~3.3, NiGa n O 4 + z ( where, n = 2.5 to 3.5)
Wherein (O 4 + z ) in the above formula
Is the amount of oxygen necessary for stable existence as a composite oxide, and the amount of oxygen changes as needed in the range of 0.2 or less depending on the value of n.
【００２１】また、本発明で用いられる複合酸化物は、
Ｇａ／Ｎｉの原子比ｎの値が２．５〜３．３の範囲を逸
脱すると触媒活性が低下するため、前記範囲に特定さ
れ、とりわけＮＯ除去率の最大値を考慮すると２．８〜
３．０が最も望ましい。The composite oxide used in the present invention comprises:
If the value of the atomic ratio n of Ga / Ni deviates from the range of 2.5 to 3.3, the catalytic activity is reduced. Therefore, the catalytic activity is specified in the above range.
3.0 is most desirable.
【００２２】[0022]
【作用】本発明の窒素酸化物除去用酸化物触媒材料並び
に窒素酸化物除去方法によれば、本発明の酸化物触媒材
料は、Ｎｉ及びＧａを金属元素として含有するスピネル
型結晶性複合酸化物に、Ｃｏ、Ｎｉ、Ｆｅ、Ｃｕ等の遷
移金属から選ばれる少なくとも１種を担持したＣｅＯ2
を５〜７５重量％添加したことから、ＣｅＯ2 自体はＮ
Ｏｘ還元分解能を示さないものの、添加されたＣｅＯ2
がＮＯを酸化してＮＯ2 の生成を促進し、ＮＯよりＮＯ
2 に対する還元活性の方が高いＮｉ−Ｇａ系酸化物触媒
により、Ｎｉ−Ｇａ触媒単独の場合よりも低温度域でＮ
Ｏｘ還元分解活性が向上するようになる。According to the oxide catalyst material for removing nitrogen oxides and the method for removing nitrogen oxides of the present invention, the oxide catalyst material of the present invention is a spinel type crystalline complex oxide containing Ni and Ga as metal elements. In addition, CeO 2 supporting at least one selected from transition metals such as Co, Ni, Fe and Cu
5 to 75% by weight of CeO 2 itself is
Added CeO 2 although not showing Ox reduction resolution
Oxidizes NO and promotes the production of NO 2 ,
The Ni-Ga-based oxide catalyst, which has a higher reduction activity for 2, has a lower N-temperature than the Ni-Ga catalyst alone.
Ox reductive decomposition activity is improved.
【００２３】更に、前記遷移金属を担持することにより
吸着酸素量が増大し、ＮＯのＮＯ2への酸化が更に促進
されて低温度域での触媒活性が向上する。Further, by supporting the transition metal, the amount of adsorbed oxygen is increased, the oxidation of NO to NO 2 is further promoted, and the catalytic activity in the low temperature range is improved.
【００２４】[0024]
【発明の実施の形態】以下、本発明の窒素酸化物除去用
酸化物触媒材料並びに窒素酸化物除去方法について、実
施例に基づき詳細に述べる。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the oxide catalyst material for removing nitrogen oxides and the method for removing nitrogen oxides of the present invention will be described in detail based on Examples.
【００２５】先ず、本発明の窒素酸化物除去用酸化物触
媒材料の製造方法について一例を詳述する。本発明の複
合酸化物は、ＮｉおよびＧａを含有する原料粉末を、Ｇ
ａ／Ｎｉの原子比ｎが２．５〜３．３となるように秤量
し、十分に撹袢混合した後、酸化性雰囲気中、５００〜
１６００℃の温度で５〜３０時間熱処理することによ
り、金属元素としてＮｉ及びＧａを含有したスピネル型
結晶を主結晶相とする複合酸化物粉末が得られる。First, an example of the method for producing the oxide catalyst material for removing nitrogen oxides of the present invention will be described in detail. The composite oxide of the present invention is obtained by converting a raw material powder containing Ni and Ga into G
After weighing so that the atomic ratio n of a / Ni is 2.5 to 3.3 and thoroughly stirring and mixing, 500 to 500 in an oxidizing atmosphere.
By performing heat treatment at a temperature of 1600 ° C. for 5 to 30 hours, a composite oxide powder containing a spinel type crystal containing Ni and Ga as a metal element as a main crystal phase can be obtained.
【００２６】前記原料粉末としては、例えば、Ｎｉ及び
Ｇａの酸化物や、熱処理により酸化物を生成するそれら
の炭酸塩、硝酸塩、酢酸塩等を用いることができる。As the raw material powder, for example, oxides of Ni and Ga, and their carbonates, nitrates, acetates or the like which produce oxides by heat treatment can be used.
【００２７】また前記複合酸化物は、前記以外に酸化物
や他の金属塩による固相反応法や、金属アルコキシド等
のゾル−ゲル法等によっても合成できるものであり、何
等これら製造方法に限定されるものではない。In addition to the above, the complex oxide can also be synthesized by a solid-phase reaction method using an oxide or another metal salt, a sol-gel method using a metal alkoxide or the like, and is not limited to these production methods. It is not something that will be done.
【００２８】前記製造方法において、いずれも熱処理
は、熱処理温度が５００℃より低いと結晶化が不十分と
なり、逆に１６００℃を越えると緻密化してしまうた
め、５００〜１６００℃の温度で、酸化雰囲気中、５〜
３０時間行うが、特に低い温度で熱処理することが粉末
の比表面積を高める上で有効であり、実用的には、比表
面積が３５ｍ2 ／ｇ以上となるように設定することが望
ましい。In any of the above-mentioned manufacturing methods, when the heat treatment temperature is lower than 500 ° C., the crystallization becomes insufficient, and when the heat treatment temperature exceeds 1600 ° C., densification occurs. 5 in the atmosphere
Although the heat treatment is performed for 30 hours, heat treatment at a particularly low temperature is effective in increasing the specific surface area of the powder, and practically, it is desirable to set the specific surface area to 35 m 2 / g or more.
【００２９】尚、ＣｅＯ2 添加時の前記複合酸化物粉末
は、排気ガスとの接触面積を確保して窒素酸化物を効果
的に分解除去するという点からは、高い比表面積を有す
るものが望ましく、その比表面積は３０〜１２０ｍ2 ／
ｇ、特に４０〜９０ｍ2 ／ｇであることが好ましい。The complex oxide powder at the time of adding CeO 2 preferably has a high specific surface area from the viewpoint of ensuring the contact area with exhaust gas and effectively decomposing and removing nitrogen oxides. , Its specific surface area is 30 to 120 m 2 /
It is preferably g, particularly 40 to 90 m 2 / g.
【００３０】次いで前記ＣｅＯ2 を担持体として、前記
所定量のＣｏ、Ｎｉ、Ｆｅ、Ｃｕの遷移金属元素から選
ばれる少なくとも１種を含有する水溶液を加えて蒸発乾
固し、大気中、５００〜７００℃の温度で１〜５時間熱
処理して本発明の遷移金属を担持したＣｅＯ2 が得られ
る。Then, using CeO 2 as a carrier, an aqueous solution containing at least one selected from the transition metal elements of Co, Ni, Fe, and Cu is added and evaporated to dryness. The transition metal-supported CeO 2 of the present invention is obtained by heat treatment at a temperature of 700 ° C. for 1 to 5 hours.
【００３１】そして前記遷移金属を担持したＣｅＯ
2 を、Ｎｉ及びＧａを含有したスピネル型結晶を主結晶
相とする複合酸化物粉末に添加して酸化物触媒材料を作
製する。And CeO carrying the above transition metal
2 is added to a composite oxide powder containing a spinel type crystal containing Ni and Ga as a main crystal phase to produce an oxide catalyst material.
【００３２】尚、前記遷移金属を担持したＣｅＯ2 の添
加方法としては、該ＣｅＯ2 粉末と前記複合酸化物粉末
をボールミルや乳鉢で粉砕混合する方法等があり、本発
明ではこれらの混合方法に何ら限定されるものではな
い。As a method of adding the CeO 2 supporting the transition metal, there is a method of pulverizing and mixing the CeO 2 powder and the complex oxide powder in a ball mill or a mortar. In the present invention, these mixing methods are used. It is not limited in any way.
【００３３】[0033]
【実施例】次に、本発明を以下に詳述するようにして評
価した。Next, the present invention was evaluated as described in detail below.
【００３４】先ず、出発原料としてＮｉ（ＮＯ3 ）2 ・
６Ｈ2 Ｏ、及びＧａ（ＮＯ3 ）2 ・９Ｈ2 Ｏの試薬を用
い、ＮｉとＧａの金属比が１対３になるように秤量し、
これらの試薬を蒸留水中に溶解させ、撹拌しながらアン
モニア水で中和し、この時、生成した沈殿物を濾過、洗
浄し、凍結乾燥させた。First, as a starting material, Ni (NO 3 ) 2
6H 2 O, and Ga (NO 3) with reagents 2 · 9H 2 O, metal ratio of Ni and Ga were weighed to be 1: 3,
These reagents were dissolved in distilled water and neutralized with aqueous ammonia while stirring. At this time, the formed precipitate was filtered, washed and freeze-dried.
【００３５】かくして得られた乾燥粉末を大気中７００
℃の温度で３０時間、熱処理して比表面積が４０〜５０
ｍ2 ／ｇのスピネル型結晶性複合酸化物粉末を得た。The dry powder thus obtained was dried in air at 700
Heat treatment at a temperature of 30 ° C. for 30 hours to have a specific surface area of 40 to 50
A spinel-type crystalline composite oxide powder of m 2 / g was obtained.
【００３６】次に、比表面積が７０ｍ2 ／ｇのＣｅＯ2
に表１乃至表２に示す量の担持元素である各遷移金属を
含有した水溶液を添加して蒸発乾固した後、大気中、６
００℃の温度で１時間熱処理して前記各遷移金属を担持
したＣｅＯ2 を得た。Next, CeO 2 having a specific surface area of 70 m 2 / g
After adding an aqueous solution containing each of the transition metals as supporting elements in the amounts shown in Tables 1 and 2 and evaporating to dryness,
00 was heat-treated for 1 hour at ℃ temperature to obtain a CeO 2 carrying the respective transition metals.
【００３７】その後、前記スピネル型複合酸化物に対し
て前記各遷移金属を担持したＣｅＯ2 粉末を表１乃至表
３に示す割合で添加混合した後、該混合粉末を金型プレ
スにより成形し、更に冷間静水圧成形法により圧縮して
から該成形物を解砕して篩別し、５００μｍを越え、７
００μｍ以下に整粒して評価試料を調製した。After that, CeO 2 powder carrying the above transition metals was added and mixed to the spinel type composite oxide at a ratio shown in Tables 1 to 3, and the mixed powder was molded by a die press, Further, after compressing by the cold isostatic pressing method, the molded product is crushed and sieved, and the size exceeds 500 μm.
An evaluation sample was prepared by adjusting the particle size to 00 μm or less.
【００３８】尚、前記遷移金属を全く担持しないＣｅＯ
2 添加スピネル型複合酸化物触媒およびスピネル型複合
酸化物触媒のみの触媒活性を比較例とした。It should be noted that CeO which does not support the transition metal at all.
The catalytic activity of the 2- added spinel-type mixed oxide catalyst and the spinel-type mixed oxide catalyst alone was set as a comparative example.
【００３９】[0039]
【表１】 [Table 1]
【００４０】[0040]
【表２】 [Table 2]
【００４１】かくして得られた評価試料の各粉末を用い
てＸ線回折測定（ＸＲＤ）により結晶相を同定し、該結
晶相がスピネル結晶とＣｅＯ2 結晶相から成ることを確
認した。Using each powder of the evaluation sample thus obtained, a crystal phase was identified by X-ray diffraction measurement (XRD), and it was confirmed that the crystal phase consisted of a spinel crystal and a CeO 2 crystal phase.
【００４２】次いで、模擬排気ガスとしてＮＯが１００
０ｐｐｍ、Ｏ2 が１０％、Ｃ3 Ｈ6が６６６ｐｐｍ、Ｈ
2 Ｏが１０％残部がＨｅから成る反応ガスを、該反応ガ
スと触媒材料が接触する条件として、空間速度（ＳＶ）
を１０００００／ｈｒ．に設定し、前記評価用試料を充
填した触媒層に流し、３００〜５００℃の温度範囲で触
媒層を通過して生成したＮ2 ガスをガスクロマトグラフ
で測定した。Next, NO is 100 as simulated exhaust gas.
0 ppm, O 2 10%, C 3 H 6 666 ppm, H
A space gas (SV) is used as a condition in which a reaction gas containing 10% of 2 O and the balance of He is made to contact the catalyst material with the reaction gas.
Of 100000 / hr. Was set, and the sample for evaluation was flown through the catalyst layer and the N 2 gas produced by passing through the catalyst layer in the temperature range of 300 to 500 ° C. was measured by a gas chromatograph.
【００４３】触媒のＮＯ還元分解能は、触媒層出口側の
Ｎ2 濃度（ｐｐｍ）の２倍の値を、触媒層入口側のＮＯ
濃度（ｐｐｍ）で除した百分率をＮＯ除去率（％）と
し、各温度でのＮＯ除去率を求めた。As for the NO reduction resolution of the catalyst, the value twice the N 2 concentration (ppm) on the catalyst layer outlet side is the NO on the catalyst layer inlet side.
The percentage divided by the concentration (ppm) was taken as the NO removal rate (%), and the NO removal rate at each temperature was determined.
【００４４】その結果から、前記測定温度範囲内で４０
０℃以下の低温度域で広範囲にＮＯ還元活性を示すもの
の内、とりわけ３５０℃以下の温度域で優れたＮＯ還元
活性を示すものを優と評価し、それ以外を良と評価し
た。From the result, it was found that the measured temperature range was 40%.
Among those showing a wide range of NO reduction activity in a low temperature range of 0 ° C. or lower, those showing an excellent NO reduction activity particularly in a temperature range of 350 ° C. or lower were evaluated as excellent and the others were evaluated as good.
【００４５】[0045]
【表３】 [Table 3]
【００４６】[0046]
【表４】 [Table 4]
【００４７】表から明らかなように、比較例である試料
番号１と３５は、それぞれ３００℃および３５０℃以下
の温度ではＮＯ還元活性は著しく低く、また本発明の請
求範囲外である試料番号３６、４４、４５、５３、５
４、６２、６３、７１はいずれも所定温度域でのＮＯ還
元活性が全体的に低く実用的でないことが分かる。As is clear from the table, the sample Nos. 1 and 35, which are comparative examples, have significantly low NO reduction activity at temperatures of 300 ° C. and 350 ° C. or lower, respectively, and are also outside the scope of the claims of the present invention. , 44, 45, 53, 5
It can be seen that NOs. 4, 62, 63 and 71 all have low NO reduction activity in a predetermined temperature range and are not practical.
【００４８】それに対して、本発明では３００〜４５０
℃の広い温度範囲で十分なＮＯ還元活性を示しているこ
とが明らかとなっている。On the other hand, in the present invention, it is 300 to 450.
It has been clarified that it exhibits sufficient NO reduction activity in a wide temperature range of ° C.
【００４９】また、本発明の前記評価用試料は、いずれ
もＳＶ値が３０００００／ｈｒ．まで、酸素濃度は１５
％まで前記諸特性の著しい低下はなく、一方、３５０℃
の温度で連続して１００時間、前記反応ガスと接触させ
て反応させた後においても前記諸特性に大きな変化は認
められなかった。The SV value of each of the evaluation samples of the present invention was 300,000 / hr. Until the oxygen concentration is 15
%, There is no significant decrease in the above properties, while 350 ° C
Even after 100 hours of continuous contact with the reaction gas for reaction at the above temperature, no significant change was observed in the above-mentioned various properties.
【００５０】更に、前記評価用試料を４気筒のディーゼ
ルエンジン台上試験装置の排気管に取り付け、該ディー
ゼルエンジンを最高回転数、全負荷の条件で１００時間
運転する耐久試験を実施し、試験後の評価用試料につい
て前記同様にしてＮＯ還元活性を評価したが、ＮＯ除去
率はほとんど低下していないことが確認でき、耐水性、
耐熱性に優れていることも証明された。Further, the evaluation sample was attached to an exhaust pipe of a four-cylinder diesel engine bench test apparatus, and a durability test was conducted in which the diesel engine was operated for 100 hours at maximum rotation speed and full load. The NO reduction activity of the sample for evaluation was evaluated in the same manner as described above, but it was confirmed that the NO removal rate hardly decreased, and the water resistance,
It also proved to be excellent in heat resistance.
【００５１】[0051]
【発明の効果】以上、詳述したように本発明の窒素酸化
物除去用酸化物触媒材料並びに窒素酸化物除去方法によ
れば、該酸化物触媒材料はニッケル（Ｎｉ）とガリウム
（Ｇａ）を主たる金属元素として含有するスピネル型結
晶性複合酸化物にＣｏ、Ｎｉ、Ｆｅ、Ｃｕの遷移金属か
ら選ばれる少なくとも１種の元素を担持したＣｅＯ2 を
５〜７５重量％添加してなることを特徴とするものであ
り、高濃度の酸素と還元性を有する炭素含有ガスが存在
する酸化雰囲気中で前記酸化物触媒材料と窒素酸化物を
含む排気ガスを接触させることから、水蒸気が存在する
雰囲気中は勿論、排気ガス中の酸素濃度が３％以上の高
酸素濃度雰囲気下であっても、その上、ガスの流速が高
速度であっても、優れたＮＯｘ還元性能を有し、排気ガ
ス中に含まれるＮＯｘを有効に還元除去することができ
る。As described above in detail, according to the oxide catalyst material for removing nitrogen oxides and the method for removing nitrogen oxides of the present invention, the oxide catalyst material contains nickel (Ni) and gallium (Ga). 5 to 75% by weight of CeO 2 carrying at least one element selected from transition metals of Co, Ni, Fe and Cu is added to a spinel type crystalline complex oxide contained as a main metal element. In the atmosphere in which water vapor exists, since the oxide catalyst material and the exhaust gas containing nitrogen oxide are brought into contact with each other in an oxidizing atmosphere in which a high concentration oxygen and a carbon-containing gas having a reducing property are present. Of course, even in a high oxygen concentration atmosphere where the oxygen concentration in the exhaust gas is 3% or more, and in addition, even if the gas flow rate is high, it has excellent NOx reduction performance, N included in It is possible to effectively reduce and remove the x.
【００５２】その結果、省エネルギー、省資源及び地球
温暖化防止を目標として開発される今後のディーゼルエ
ンジンやリーンバーンエンジン等の各種内燃機関の排気
ガスをはじめ、ＮＯｘを含有する各種有害物質の浄化に
極めて有用なものとなる。As a result, in purifying exhaust gases from various internal combustion engines such as diesel engines and lean-burn engines, which are developed for the purpose of energy saving, resource saving and prevention of global warming, and various harmful substances containing NOx. It will be extremely useful.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 松本 秀美 鹿児島県国分市山下町１番４号 京セラ株 式会社総合研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hidemi Matsumoto Inventor Hidemi 1-4 Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Corporation General Research Institute
Claims (6)
たる金属元素として含有するスピネル型結晶性複合酸化
物に、コバルト（Ｃｏ）、ニッケル（Ｎｉ）、鉄（Ｆ
ｅ）、銅（Ｃｕ）の遷移金属から選ばれる少なくとも１
種を担持した酸化セリウム（ＣｅＯ2 ）を５〜７５重量
％添加して成ることを特徴とする窒素酸化物除去用酸化
物触媒材料。1. A spinel-type crystalline composite oxide containing nickel (Ni) and gallium (Ga) as main metal elements includes cobalt (Co), nickel (Ni), and iron (F).
e), at least 1 selected from transition metals of copper (Cu)
An oxide catalyst material for removing nitrogen oxides, comprising 5 to 75% by weight of cerium oxide (CeO 2 ) carrying a seed.
０重量％添加して成ることを特徴とする請求項１記載の
窒素酸化物除去用酸化物触媒材料。2. The cerium oxide (CeO 2 ) is added in an amount of 10-5.
The oxide catalyst material for removing nitrogen oxides according to claim 1, wherein the oxide catalyst material is added in an amount of 0% by weight.
０重量％添加してなることを特徴とする請求項１記載の
窒素酸化物除去用酸化物触媒材料。3. The cerium oxide (CeO 2 ) is added in an amount of 10 to 4
The oxide catalyst material for nitrogen oxide removal according to claim 1, wherein the oxide catalyst material is added in an amount of 0% by weight.
する酸化雰囲気中で、ニッケル（Ｎｉ）とガリウム（Ｇ
ａ）を主たる金属元素として含有するスピネル型結晶性
複合酸化物に、コバルト（Ｃｏ）、ニッケル（Ｎｉ）、
鉄（Ｆｅ）、銅（Ｃｕ）の遷移金属から選ばれる少なく
とも１種を担持した酸化セリウム（ＣｅＯ2 ）を５〜７
５重量％添加して成る窒素酸化物除去用酸化物触媒材料
と、窒素酸化物を含む排気ガスとを接触させることを特
徴とする窒素酸化物除去方法。4. Nickel (Ni) and gallium (G) in an oxidizing atmosphere in which a carbon-containing gas having a reducing property with oxygen is present.
Cobalt (Co), nickel (Ni), spinel type crystalline complex oxide containing a) as a main metal element,
Cerium oxide (CeO 2 ) carrying at least one selected from transition metals such as iron (Fe) and copper (Cu) is added to 5 to 7
A method for removing nitrogen oxides, which comprises contacting an oxide catalyst material for removing nitrogen oxides, which is added by 5% by weight, with exhaust gas containing nitrogen oxides.
０重量％添加して成る窒素酸化物除去用酸化物触媒材料
と、窒素酸化物を含む排気ガスとを接触させることを特
徴とする請求項４記載の窒素酸化物除去方法。5. The cerium oxide (CeO 2 ) is added in an amount of 10-5.
5. The method for removing nitrogen oxides according to claim 4, wherein an oxide catalyst material for removing nitrogen oxides, which is added by 0% by weight, is brought into contact with exhaust gas containing nitrogen oxides.
０重量％添加して成る窒素酸化物除去用酸化物触媒材料
と、窒素酸化物を含む排気ガスとを接触させることを特
徴とする請求項４記載の窒素酸化物除去方法。6. The cerium oxide (CeO 2 ) is added in an amount of 10 to 4
5. The method for removing nitrogen oxides according to claim 4, wherein an oxide catalyst material for removing nitrogen oxides, which is added by 0% by weight, is brought into contact with exhaust gas containing nitrogen oxides.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7304686A JPH09141102A (en) | 1995-11-22 | 1995-11-22 | Oxide catalyst material for removing nitrogen oxide and removal of nitrogen oxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7304686A JPH09141102A (en) | 1995-11-22 | 1995-11-22 | Oxide catalyst material for removing nitrogen oxide and removal of nitrogen oxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09141102A true JPH09141102A (en) | 1997-06-03 |
Family
ID=17936006
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7304686A Pending JPH09141102A (en) | 1995-11-22 | 1995-11-22 | Oxide catalyst material for removing nitrogen oxide and removal of nitrogen oxide |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09141102A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016019955A (en) * | 2014-07-15 | 2016-02-04 | 株式会社キャタラー | Catalyst for exhaust gas purification |
| JPWO2014103597A1 (en) * | 2012-12-27 | 2017-01-12 | 三井金属鉱業株式会社 | Exhaust gas purification catalyst composition and exhaust gas purification catalyst |
-
1995
- 1995-11-22 JP JP7304686A patent/JPH09141102A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2014103597A1 (en) * | 2012-12-27 | 2017-01-12 | 三井金属鉱業株式会社 | Exhaust gas purification catalyst composition and exhaust gas purification catalyst |
| US10350581B2 (en) | 2012-12-27 | 2019-07-16 | Mitsui Mining & Smelting Co., Ltd. | Catalyst composition for exhaust gas purification and catalyst for exhaust gas purification |
| JP2016019955A (en) * | 2014-07-15 | 2016-02-04 | 株式会社キャタラー | Catalyst for exhaust gas purification |
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