JP2009208011A - Exhaust gas cleaning catalyst and its manufacturing method - Google Patents
Exhaust gas cleaning catalyst and its manufacturing method Download PDFInfo
- Publication number
- JP2009208011A JP2009208011A JP2008054199A JP2008054199A JP2009208011A JP 2009208011 A JP2009208011 A JP 2009208011A JP 2008054199 A JP2008054199 A JP 2008054199A JP 2008054199 A JP2008054199 A JP 2008054199A JP 2009208011 A JP2009208011 A JP 2009208011A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- type
- gas purification
- purification catalyst
- composite oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 47
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 238000004140 cleaning Methods 0.000 title abstract 6
- 239000002131 composite material Substances 0.000 claims abstract description 27
- 239000002245 particle Substances 0.000 claims abstract description 27
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 25
- 238000002485 combustion reaction Methods 0.000 claims abstract description 8
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 5
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 5
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 5
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims abstract description 4
- 238000000746 purification Methods 0.000 claims description 57
- 239000013078 crystal Substances 0.000 claims description 9
- 230000002950 deficient Effects 0.000 claims description 7
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 5
- 239000010436 fluorite Substances 0.000 claims description 5
- YDZQQRWRVYGNER-UHFFFAOYSA-N iron;titanium;trihydrate Chemical compound O.O.O.[Ti].[Fe] YDZQQRWRVYGNER-UHFFFAOYSA-N 0.000 claims description 5
- 238000010303 mechanochemical reaction Methods 0.000 claims description 5
- 150000004706 metal oxides Chemical class 0.000 claims description 5
- 229910052596 spinel Inorganic materials 0.000 claims description 5
- 239000011029 spinel Substances 0.000 claims description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 4
- 239000007789 gas Substances 0.000 description 53
- 230000000052 comparative effect Effects 0.000 description 22
- 239000010948 rhodium Substances 0.000 description 19
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 18
- 238000005259 measurement Methods 0.000 description 14
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000011156 evaluation Methods 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 7
- 239000007787 solid Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 230000008020 evaporation Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 238000002441 X-ray diffraction Methods 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 239000004570 mortar (masonry) Substances 0.000 description 4
- 229910052703 rhodium Inorganic materials 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 229910052712 strontium Inorganic materials 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052763 palladium Inorganic materials 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- 238000001308 synthesis method Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910002204 La0.8Sr0.2MnO3 Inorganic materials 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000012495 reaction gas Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000005574 cross-species transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Abstract
Description
本発明は、内燃機関から排出される排ガス中に含まれるＨＣ、ＣＯ、及びＮＯｘを浄化するために用いられる排ガス浄化触媒及びその製造方法に関し、特に、優れた排ガス浄化性能を有する排ガス浄化触媒及びその製造方法に関する。 The present invention relates to an exhaust gas purification catalyst used for purifying HC, CO, and NOx contained in exhaust gas discharged from an internal combustion engine and a method for producing the same, and in particular, an exhaust gas purification catalyst having excellent exhaust gas purification performance and It relates to the manufacturing method.
従来より、内燃機関から排出される排ガス中に含まれるＨＣ（炭化水素）、ＣＯ（一酸化炭素）、及びＮＯｘ（窒素酸化物）を同時に浄化できる排ガス浄化触媒として、Ｐｔ（白金）、Ｒｈ（ロジウム）、Ｐｄ（パラジウム）等の貴金属が、触媒活性成分として広く用いられている。 Conventionally, as an exhaust gas purification catalyst capable of simultaneously purifying HC (hydrocarbon), CO (carbon monoxide), and NOx (nitrogen oxide) contained in exhaust gas discharged from an internal combustion engine, Pt (platinum), Rh ( Noble metals such as rhodium) and Pd (palladium) are widely used as catalytic active components.
例えば、Ｐｄを必須成分とするペロブスカイト型構造の複合酸化物を含むように調製された排ガス浄化触媒が開示されている（例えば、特許文献１参照）。この排ガス浄化触媒によれば、Ｐｄが有する高い触媒活性を長期に亘って維持でき、優れた排ガス浄化性能を実現できるとされている。
しかしながら、近年の排ガス規制の強化に対応するためには、従来の排ガス浄化触媒が有する浄化性能では十分とは言えず、さらなる浄化性能の向上が望まれている。また、Ｐｔ、Ｒｈ、Ｐｄ等の貴金属は、非常に高価な材料であることから、少ない使用量で高い浄化活性が得られるような優れた浄化性能を有する排ガス浄化触媒が求められている。 However, in order to respond to the recent tightening of exhaust gas regulations, the purification performance of conventional exhaust gas purification catalysts is not sufficient, and further improvement in purification performance is desired. Further, since noble metals such as Pt, Rh, and Pd are very expensive materials, there is a demand for an exhaust gas purification catalyst having an excellent purification performance that can provide high purification activity with a small amount of use.
本発明は、以上のような課題に鑑みてなされたものであり、その目的は、従来の排ガス浄化触媒に比して優れた排ガス浄化性能を有する排ガス浄化触媒、及びその製造方法を提供することにある。 The present invention has been made in view of the above problems, and an object of the present invention is to provide an exhaust gas purification catalyst having an exhaust gas purification performance superior to conventional exhaust gas purification catalysts, and a method for producing the same. It is in.
本発明者らは、上記課題を解決するために鋭意研究を重ねた。その結果、担体としての複合酸化物粒子に対して、その中心部から表面方向に貴金属元素の含有量が漸次増加するように貴金属を傾斜担持させることにより、従来の排ガス浄化触媒に比して優れた排ガス浄化性能を有する排ガス浄化触媒が得られることを見出し、本発明を完成するに至った。より具体的には、本発明は以下のようなものを提供する。 The inventors of the present invention have made extensive studies to solve the above problems. As a result, the composite oxide particles as a carrier are superior to conventional exhaust gas purification catalysts by supporting the precious metal in an inclined manner so that the content of the precious metal element gradually increases from the center to the surface. The present inventors have found that an exhaust gas purification catalyst having exhaust gas purification performance can be obtained, and have completed the present invention. More specifically, the present invention provides the following.
請求項１記載の発明は、内燃機関から排出される排ガス中に含まれるＨＣ、ＣＯ、及びＮＯｘを浄化するために用いられる排ガス浄化触媒であって、貴金属元素と、アルカリ金属元素、アルカリ土類金属元素、希土類元素、及び遷移金属元素よりなる群から選ばれる少なくとも１種の元素と、を含む複合酸化物粒子で構成され、前記複合酸化物粒子は、中心部から表面方向に前記貴金属元素の含有量が漸次増加する傾斜構造を有することを特徴とする。 The invention according to claim 1 is an exhaust gas purification catalyst used for purifying HC, CO, and NOx contained in exhaust gas discharged from an internal combustion engine, wherein the noble metal element, alkali metal element, alkaline earth A composite oxide particle including at least one element selected from the group consisting of a metal element, a rare earth element, and a transition metal element, and the composite oxide particle is formed of the noble metal element in a surface direction from a center portion. It is characterized by having an inclined structure in which the content gradually increases.
請求項２記載の発明は、請求項１記載の排ガス浄化触媒において、前記複合酸化物粒子は、フルオライト型、ペロブスカイト型、スピネル型、ルチル型、デラフォサイト型、マグネトプランバイト型、及びイルメナイト型よりなる群から選ばれる少なくとも１種の結晶構造を有することを特徴とする。
The invention according to
請求項３記載の発明は、内燃機関から排出される排ガス中に含まれるＨＣ、ＣＯ、及びＮＯｘを浄化するために用いられる排ガス浄化触媒の製造方法であって、Ｂサイト欠損型複合酸化物と貴金属酸化物とを混合し、ボールミルを用いたメカノケミカル反応を行う工程を有することを特徴とする。 The invention according to claim 3 is a method for producing an exhaust gas purification catalyst used for purifying HC, CO, and NOx contained in exhaust gas discharged from an internal combustion engine, comprising: a B site deficient complex oxide; It has the process of mixing a noble metal oxide and performing a mechanochemical reaction using a ball mill.
請求項４記載の発明は、請求項３記載の排ガス浄化触媒の製造方法において、前記Ｂサイト欠損型複合酸化物として、フルオライト型、ペロブスカイト型、スピネル型、ルチル型、デラフォサイト型、マグネトプランバイト型、及びイルメナイト型よりなる群から選ばれる少なくとも１種の結晶構造を有する複合酸化物を用いることを特徴とする。 According to a fourth aspect of the present invention, there is provided the method for producing an exhaust gas purifying catalyst according to the third aspect, wherein the B site deficient complex oxide includes a fluorite type, a perovskite type, a spinel type, a rutile type, a delafossite type, a magneto A composite oxide having at least one crystal structure selected from the group consisting of a plumbite type and an ilmenite type is used.
本発明によれば、従来の排ガス浄化触媒に比して優れた排ガス浄化性能を有する排ガス浄化触媒、及びその製造方法を提供できる。 ADVANTAGE OF THE INVENTION According to this invention, the exhaust gas purification catalyst which has the exhaust gas purification performance outstanding compared with the conventional exhaust gas purification catalyst, and its manufacturing method can be provided.
以下、本発明の実施形態について詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
＜排ガス浄化触媒＞
本実施形態に係る排ガス浄化触媒は、内燃機関から排出される排ガス中に含まれるＨＣ、ＣＯ、及びＮＯｘを浄化するために用いられ、貴金属元素と、アルカリ金属元素、アルカリ土類金属元素、希土類元素、及び遷移金属元素よりなる群から選ばれる少なくとも１種の元素と、を含む複合酸化物粒子から構成される。
<Exhaust gas purification catalyst>
The exhaust gas purification catalyst according to the present embodiment is used to purify HC, CO, and NOx contained in exhaust gas discharged from an internal combustion engine, and includes a noble metal element, an alkali metal element, an alkaline earth metal element, and a rare earth element. The composite oxide particle includes at least one element selected from the group consisting of an element and a transition metal element.
本実施形態に係る排ガス浄化触媒を構成する複合酸化物粒子は、中心部から表面方向に貴金属元素の含有量が漸次増加する傾斜構造を有することを特徴とする。即ち、複合酸化物粒子の表面に貴金属を固溶させたものであり、複合酸化物粒子の内部よりも表面に多く貴金属が傾斜担持されている。このため、本実施形態に係る排ガス浄化触媒は、貴金属の活性点が複合酸化物粒子の内部に取り込まれて触媒活性の発揮が妨げられるということが無く、少ない貴金属量で高い活性を発揮できる。 The composite oxide particles constituting the exhaust gas purifying catalyst according to the present embodiment are characterized by having an inclined structure in which the content of the noble metal element gradually increases from the central portion toward the surface. That is, the noble metal is solid-solved on the surface of the composite oxide particle, and more noble metal is supported on the surface than the inside of the composite oxide particle. For this reason, the exhaust gas purifying catalyst according to this embodiment can exhibit high activity with a small amount of noble metal without the active point of the noble metal being taken into the composite oxide particles to hinder the catalytic activity.
貴金属としては特に限定されず、Ｐｔ、Ｒｈ、Ｐｄ等の貴金属が用いられる。また、複合酸化物粒子としては、フルオライト型、ペロブスカイト型、スピネル型、ルチル型、デラフォサイト型、マグネトプランバイト型、及びイルメナイト型よりなる群から選ばれる少なくとも１種の結晶構造を有するものであることが好ましい。これらの結晶構造を有する複合酸化物は、耐熱性が良好であることから、高温雰囲気下に晒された場合であっても、排ガス浄化性能に変化が生じることがほとんどない。 The noble metal is not particularly limited, and noble metals such as Pt, Rh, and Pd are used. The composite oxide particles have at least one crystal structure selected from the group consisting of fluorite type, perovskite type, spinel type, rutile type, delafossite type, magnetoplumbite type, and ilmenite type. It is preferable that Since the complex oxides having these crystal structures have good heat resistance, the exhaust gas purification performance hardly changes even when exposed to a high temperature atmosphere.
また、これらの結晶構造を有する複合酸化物には、Ｂサイト欠損型複合酸化物が含まれることから、欠損したＢサイトに貴金属元素をドープすることにより、貴金属を複合酸化物に担持させることができる。さらには、後述するメカノケミカル合成法によれば、複合酸化物全体ではなく、複合酸化物粒子の表面に多くの貴金属元素をドープでき、本実施形態に係る排ガス浄化触媒を容易に得ることができる。なお、上述した通り、貴金属は複合酸化物粒子の表面に固溶された状態であることから、複合酸化物の結晶構造が変化することはなく、上記列挙した結晶構造が維持される。 In addition, since complex oxides having these crystal structures include B-site deficient complex oxides, noble metals can be supported on the complex oxides by doping the deficient B sites with noble metal elements. it can. Furthermore, according to the mechanochemical synthesis method described later, a large amount of noble metal elements can be doped on the surface of the composite oxide particles, not the entire composite oxide, and the exhaust gas purification catalyst according to the present embodiment can be easily obtained. . As described above, since the noble metal is in a solid solution state on the surface of the composite oxide particle, the crystal structure of the composite oxide does not change, and the crystal structures listed above are maintained.
＜製造方法＞
本実施形態に係る排ガス浄化触媒の製造方法は、Ｂサイト欠損型複合酸化物と貴金属酸化物とを混合し、ボールミルを用いたメカノケミカル反応を行う工程を有することを特徴とする。本実施形態に係る排ガス浄化触媒の製造方法によれば、複合酸化物粒子の中心部から表面方向に貴金属元素の含有量が漸次増加する傾斜構造を有する排ガス浄化触媒が得られる。
<Manufacturing method>
The method for producing an exhaust gas purifying catalyst according to the present embodiment includes a step of mixing a B-site deficient complex oxide and a noble metal oxide and performing a mechanochemical reaction using a ball mill. According to the method for producing an exhaust gas purification catalyst according to the present embodiment, an exhaust gas purification catalyst having an inclined structure in which the content of the noble metal element gradually increases from the center of the composite oxide particles toward the surface can be obtained.
メカノケミカル反応とは、固体粒子を粉砕して微粒子化する過程において、微粒子化した固体粒子に、衝撃、せん断、ずり応力、摩擦等の機械的エネルギーを付与することにより生ずる反応をいう。メカノケミカル反応では、固体粒子に付与した機械的エネルギーの一部が固体粒子内に蓄積され、固体粒子の活性・反応性が高まる結果、周囲の物質と化学反応が行われる。 The mechanochemical reaction refers to a reaction that occurs by applying mechanical energy such as impact, shear, shear stress, friction, etc. to the finely divided solid particles in the process of pulverizing the solid particles into fine particles. In the mechanochemical reaction, a part of the mechanical energy imparted to the solid particles is accumulated in the solid particles, and the activity and reactivity of the solid particles increase, resulting in a chemical reaction with surrounding substances.
ボールミルは、セラミック等の硬質のボールとともに、固体粒子を容器に入れて回転させることにより、固体粒子をすり潰して微細な粉末を得る装置である。本実施形態では、従来公知のボールミルが用いられる。 A ball mill is an apparatus that obtains a fine powder by grinding solid particles together with hard balls such as ceramics in a container and rotating them. In the present embodiment, a conventionally known ball mill is used.
本実施形態に係る排ガス浄化触媒の製造方法の一例を説明する。先ず、蒸発乾固法により複合酸化物を調製する。蒸発乾固法としては特に限定されず、従来公知の蒸発乾固法が採用される。例えば、アルカリ金属元素、アルカリ土類金属元素、希土類元素、遷移金属元素等の金属塩を水に溶解させた後、蒸発乾固してから予備焼成、本焼成を順次行うことにより、複合酸化物が調製される。なお、予備焼成、本焼成の焼成条件も特に限定されない。 An example of the manufacturing method of the exhaust gas purification catalyst according to the present embodiment will be described. First, a composite oxide is prepared by evaporation to dryness. The evaporating and drying method is not particularly limited, and a conventionally known evaporating and drying method is employed. For example, a metal oxide such as an alkali metal element, an alkaline earth metal element, a rare earth element, or a transition metal element is dissolved in water, evaporated to dryness, and then subjected to preliminary firing and main firing in order, thereby producing a composite oxide. Is prepared. Note that the firing conditions for the pre-baking and the main baking are not particularly limited.
次いで、調製した複合酸化物に、貴金属酸化物を添加して乳鉢で混合した後、ボールミルで攪拌する。攪拌時間は、３０分以上であることが好ましい。攪拌後、得られた粉末を焼成することにより、本実施形態に係る排ガス浄化触媒が得られる。 Next, a noble metal oxide is added to the prepared composite oxide and mixed in a mortar, and then stirred with a ball mill. The stirring time is preferably 30 minutes or longer. After the stirring, the obtained powder is fired to obtain the exhaust gas purification catalyst according to the present embodiment.
本発明を実施例に基づいてさらに詳細に説明するが、本発明はこれに限定されるものではない。 The present invention will be described in more detail based on examples, but the present invention is not limited thereto.
＜実施例１＞
Ｌａ、Ｓｒ、Ｍｎの金属酢酸塩を水に溶解させ、蒸発乾固（Ｌａ：４０ｍｏｌ％、Ｓｒ：１０ｍｏ１％、Ｍｎ：４９．５ｍｏｌ％）させた後、３５０℃×２ｈｒの予備焼成を行った。次いで、８５０℃×１０ｈｒの焼成を行い、Ｌａ０．８Ｓｒ０．２Ｍｎ０．９９Ｏ３のペロブスカイト型複合酸化物を調製した。
<Example 1>
La, Sr, and Mn metal acetates were dissolved in water and evaporated to dryness (La: 40 mol%, Sr: 10 mo 1%, Mn: 49.5 mol%), and then pre-baked at 350 ° C. for 2 hours. . Next, firing at 850 ° C. × 10 hr was performed to prepare a La 0.8 Sr 0.2 Mn 0.99 O 3 perovskite complex oxide.
上記のようにして調製した、Ｌａ０．８Ｓｒ０．２Ｍｎ０．９９Ｏ３のペロブスカイト型複合酸化物に対し、Ｒｈ元素換算で０．５ｍｏｌ％となるようにＲｈ２Ｏ３を加えて乳鉢で混合した。次いで、遊星型ボールミルで７００ｒｐｍ×５ｈｒ処理した後、さらに７００℃×１ｈｒの焼成を行い、排ガス浄化触媒を得た。 Rh 2 O 3 was added to the perovskite complex oxide of La 0.8 Sr 0.2 Mn 0.99 O 3 prepared as described above so as to be 0.5 mol% in terms of Rh element. Mix in mortar. Next, after processing at 700 rpm × 5 hr with a planetary ball mill, firing at 700 ° C. × 1 hr was further performed to obtain an exhaust gas purification catalyst.
＜比較例１＞
Ｌａ、Ｓｒ、Ｍｎの金属酢酸塩と、Ｒｈ２Ｏ３とを水に溶解させ、蒸発乾固（Ｌａ：４０ｍｏｌ％、Ｓｒ：１０ｍｏｌ％、Ｍｎ：４９．５ｍｏｌ％、Ｒｈ：０．５ｍｏｌ％）させた後、３５０℃×２ｈｒの予備焼成を行った。次いで、８５０℃×１０ｈｒの焼成を行い、排ガス浄化触媒を得た。
<Comparative Example 1>
La, Sr, Mn metal acetate and Rh 2 O 3 are dissolved in water and evaporated to dryness (La: 40 mol%, Sr: 10 mol%, Mn: 49.5 mol%, Rh: 0.5 mol%) Then, preliminary baking at 350 ° C. × 2 hr was performed. Next, firing at 850 ° C. × 10 hr was performed to obtain an exhaust gas purification catalyst.
＜比較例２＞
比較例１で調製した複合酸化物を乳鉢で混合し、遊星型ボールミルで７００ｒｐｍ×５ｈｒ処理した。その後、さらに７００℃×ｌｈｒの焼成を行い、排ガス浄化触媒を得た。
<Comparative Example 2>
The composite oxide prepared in Comparative Example 1 was mixed in a mortar and treated with a planetary ball mill at 700 rpm × 5 hr. Thereafter, firing was further performed at 700 ° C. × lhr to obtain an exhaust gas purification catalyst.
＜比較例３＞
実施例１と同様にして、Ｌａ０．８Ｓｒ０．２Ｍｎ０．９９Ｏ３のペロブスカイト型複合酸化物を調製した。このペロブスカイト型複合酸化物に対して、Ｒｈ元素換算で０．５ｍｏｌ％となるようにＲｈ２Ｏ３を加えて乳鉢で混合した後、実施例１と異なりボールミル処理することなく、７００℃×１ｈｒの焼成を行い、排ガス浄化触媒を得た。
<Comparative Example 3>
In the same manner as in Example 1, a perovskite complex oxide of La 0.8 Sr 0.2 Mn 0.99 O 3 was prepared. Rh 2 O 3 was added to the perovskite complex oxide in an amount of 0.5 mol% in terms of Rh element, mixed in a mortar, and unlike Example 1, 700 ° C. × 1 hr without ball milling. Was fired to obtain an exhaust gas purification catalyst.
＜ＴＰＲ測定評価＞
実施例及び比較例で調製した各排ガス浄化触媒について、ＴＰＲ（昇温還元法）測定を実施した。測定は、下記に示す手順に従って行った。測定の結果、得られたスペクトルを図１に示した。
［測定手順］
（１）Ｈｅ中で昇温させ、６００℃×３０分間保持した。
（２）Ａｉｒ中で６００℃×３０分間保持した後、３５℃まで降温させた。
（３）Ｈｅ中で５分間保持した。
（４）５％Ｈ２／Ｎ２中で、５℃／分で６００℃まで昇温させた。
<TPR measurement evaluation>
About each exhaust gas purification catalyst prepared by the Example and the comparative example, TPR (temperature rising reduction method) measurement was implemented. The measurement was performed according to the procedure shown below. The spectrum obtained as a result of the measurement is shown in FIG.
[Measurement procedure]
(1) The temperature was raised in He and held at 600 ° C. for 30 minutes.
(2) After holding at 600 ° C. for 30 minutes in Air, the temperature was lowered to 35 ° C.
(3) Hold in He for 5 minutes.
(4) The temperature was raised to 600 ° C. at 5 ° C./min in 5% H 2 / N 2 .
図１に示されるように、ボールミル処理を施していない比較例３の場合には、水素消費量からＲｈ２Ｏ３が還元されて還元ピークが２００℃以下に見られるが、実施例１のスペクトルにおいてＲｈ２Ｏ３の還元ピークは認められず、Ｒｈはペロブスカイト型複合酸化物中に固溶していると考えられた。また、Ｍｎの還元ピークが比較例では４００℃前後に見られたところ、実施例１では３００℃以下の低温側にシフトしていた。これは、ＲｈによりＭｎイオンの還元が促進されたためであると考えられた（スピルオーバー効果）。即ち、実施例１では、ペロブスカイト型複合酸化物の粒子にＲｈがドープされ、且つ複合酸化物粒子の表面近傍にＲｈが濃縮されていると考えられた。 As shown in FIG. 1, in the case of Comparative Example 3 where the ball mill treatment was not performed, Rh 2 O 3 was reduced from the hydrogen consumption and a reduction peak was observed at 200 ° C. or lower. In FIG. 2, no reduction peak of Rh 2 O 3 was observed, and Rh was considered to be dissolved in the perovskite complex oxide. Moreover, when the reduction peak of Mn was observed at around 400 ° C. in the comparative example, in Example 1, it was shifted to a low temperature side of 300 ° C. or lower. This was considered to be because reduction of Mn ions was promoted by Rh (spillover effect). That is, in Example 1, it was considered that Rh was doped in the perovskite complex oxide particles and that Rh was concentrated in the vicinity of the surface of the complex oxide particles.
＜Ｘ線回折測定評価＞
実施例及び比較例で調製した各排ガス浄化触媒について、下記に示す測定条件に従ってＸ線回折測定を実施した。測定の結果、得られたスペクトルを図２に示した。
［測定条件］
装置：Ｒｉｇａｋｕ社製「ＲＩＮＴ２０００」
Ｘ線：Ｃｕ−Ｋα
２θ：１０°〜８０°
スキャン速度：２°／分
<X-ray diffraction measurement evaluation>
About each exhaust gas purification catalyst prepared by the Example and the comparative example, the X-ray-diffraction measurement was implemented according to the measurement conditions shown below. The spectrum obtained as a result of the measurement is shown in FIG.
[Measurement condition]
Apparatus: “RINT2000” manufactured by Rigaku
X-ray: Cu-Kα
2θ: 10 ° -80 °
Scan speed: 2 ° / min
図２に示されるように、ベースとなる複合酸化物（Ｌａ０．８Ｓｒ０．２ＭｎＯ３）のＸ線回折スペクトルでは、Ｌａ０．８Ｓｒ０．２ＭｎＯ３のピークのみ見られ、Ｒｈ２Ｏ３のピークが見られないことから、実施例１、比較例１及び２いずれも、Ｒｈがペロブスカイト型複合酸化物中にドープされていることが示唆された。 As shown in FIG. 2, in the X-ray diffraction spectrum of the base complex oxide (La 0.8 Sr 0.2 MnO 3 ), only a peak of La 0.8 Sr 0.2 MnO 3 is seen, and Rh From the fact that no 2 O 3 peak was observed, it was suggested that in both Example 1 and Comparative Examples 1 and 2, Rh was doped in the perovskite complex oxide.
＜ＢＥＴ比表面積測定評価＞
実施例及び比較例で調製した各排ガス浄化触媒について、下記に示す測定条件に従ってＢＥＴ比表面積測定を実施した。測定の結果、得られた結晶子径、比表面積を表１に示した。
［測定条件］
装置：ユアサアイオニクス（株）製「ＮＯＶＡ２０００」
吸着ガス：Ｎ２
<BET specific surface area measurement evaluation>
About each exhaust gas purification catalyst prepared by the Example and the comparative example, the BET specific surface area measurement was implemented according to the measurement conditions shown below. As a result of the measurement, the obtained crystallite diameter and specific surface area are shown in Table 1.
[Measurement condition]
Equipment: “NOVA2000” manufactured by Yuasa Ionics Co., Ltd.
Adsorption gas: N 2
表１に示されるように、結晶子径及び比表面積いずれにおいても、比較例に比して実施例１が優れている因子は認められなかった。このことから、浄化性能の向上は、複合酸化物粒子の内部から表面方向にＲｈの含有量が増加するように傾斜担持されたことによる効果であると考えられた。 As shown in Table 1, in any of the crystallite diameter and the specific surface area, no factor that the example 1 was superior to the comparative example was recognized. From this, it was considered that the improvement in the purification performance was an effect due to the fact that the support was inclined so that the content of Rh increased from the inside of the composite oxide particles to the surface direction.
＜浄化性能評価＞
実施例及び比較例で調製された各排ガス浄化触媒について、図３に示すような浄化性能評価装置１０を作製し、これを用いて浄化性能の評価を行った。
<Purification performance evaluation>
For each exhaust gas purification catalyst prepared in the examples and comparative examples, a purification
具体的には、以下のような条件によるＣＯ−Ｏ２反応及びＮＯ−ＣＯ反応により、ＣＯ及びＮＯに対する浄化性能を評価した。 Specifically, the purification performance for CO and NO was evaluated by the CO—O 2 reaction and the NO—CO reaction under the following conditions.
［ＣＯ−Ｏ２反応］
ＣＯ（０．４９質量％）−Ｏ２（０．２５５質量％）−Ｈｅ（バランスガス）の反応ガスを、実施例及び比較例で調製された各排ガス浄化触媒（０．０４ｇ）に流通（Ｗ／Ｆ＝０．０１２ｇ・ｓ／ｍＬ）させた。
[CO-O 2 reaction]
A reaction gas of CO (0.49% by mass) -O 2 (0.255% by mass) -He (balance gas) was circulated through each exhaust gas purification catalyst (0.04 g) prepared in Examples and Comparative Examples ( W / F = 0.012 g · s / mL).
［ＮＯ−ＣＯ反応］
ＮＯ（０．５２質量％）−ＣＯ（０．４９質量％）−Ｈｅ（バランスガス）の反応ガスを、実施例及び比較例で調製された各排ガス浄化触媒（０．０４ｇ）に流通（Ｗ／Ｆ＝０．０１２ｇ・ｓ／ｍＬ）させた。
[NO-CO reaction]
A reaction gas of NO (0.52% by mass) -CO (0.49% by mass) -He (balance gas) is circulated through each exhaust gas purification catalyst (0.04 g) prepared in Examples and Comparative Examples (W /F=0.012 g · s / mL).
ボールミル合成法（実施例１）と、従来手法である蒸発乾固法（比較例１）、蒸発乾固法を行った後ボールミルで混合しさらに熱処理を行った場合（比較例２）とについて、昇温テストによるＣＯ転化率（図４参照）及びＮＯ転化率（図５参照）の比較を行った。蒸発乾固法（比較例１）と蒸発乾固＋ボールミル（比較例２）とでは、浄化特性にほとんど差異が見られなかったのに対し、ボールミル合成法（実施例１）では大幅な浄化特性の向上が確認された。 Regarding the ball mill synthesis method (Example 1), the conventional method of evaporation to dryness (Comparative Example 1), the case of mixing by a ball mill after performing evaporation to dryness and further heat treatment (Comparative Example 2) Comparison of CO conversion rate (see FIG. 4) and NO conversion rate (see FIG. 5) by a temperature increase test was performed. The evaporation and drying method (Comparative Example 1) and evaporation to dryness + ball mill (Comparative Example 2) showed almost no difference in purification characteristics, whereas the ball mill synthesis method (Example 1) showed significant purification characteristics. Improvement was confirmed.
１ 圧力調整弁
２ 停止弁
３ 流量調整弁
４ 流量計
５ 改質器
６ 電気炉
７ ガスサンプラー
８ ガスクロマトグラフィー
１０ 浄化性能評価装置
DESCRIPTION OF SYMBOLS 1
Claims (4)
貴金属元素と、アルカリ金属元素、アルカリ土類金属元素、希土類元素、及び遷移金属元素よりなる群から選ばれる少なくとも１種の元素と、を含む複合酸化物粒子で構成され、
前記複合酸化物粒子は、中心部から表面方向に前記貴金属元素の含有量が漸次増加する傾斜構造を有することを特徴とする排ガス浄化触媒。 An exhaust gas purification catalyst used to purify HC, CO, and NOx contained in exhaust gas discharged from an internal combustion engine,
Composed of noble metal elements and composite oxide particles containing at least one element selected from the group consisting of alkali metal elements, alkaline earth metal elements, rare earth elements, and transition metal elements,
The exhaust gas purification catalyst, wherein the composite oxide particles have an inclined structure in which the content of the noble metal element gradually increases from the center toward the surface.
Ｂサイト欠損型複合酸化物と貴金属酸化物とを混合し、ボールミルを用いたメカノケミカル反応を行う工程を有することを特徴とする排ガス浄化触媒の製造方法。 An exhaust gas purification catalyst manufacturing method used for purifying HC, CO, and NOx contained in exhaust gas discharged from an internal combustion engine,
A method for producing an exhaust gas purification catalyst, comprising a step of mixing a B-site deficient complex oxide and a noble metal oxide and performing a mechanochemical reaction using a ball mill.
The B-site deficient complex oxide has at least one crystal structure selected from the group consisting of fluorite type, perovskite type, spinel type, rutile type, delafossite type, magnetoplumbite type, and ilmenite type. 4. The method for producing an exhaust gas purification catalyst according to claim 3, wherein a composite oxide is used.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008054199A JP5101346B2 (en) | 2008-03-05 | 2008-03-05 | Exhaust gas purification catalyst and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008054199A JP5101346B2 (en) | 2008-03-05 | 2008-03-05 | Exhaust gas purification catalyst and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2009208011A true JP2009208011A (en) | 2009-09-17 |
| JP5101346B2 JP5101346B2 (en) | 2012-12-19 |
Family
ID=41181685
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2008054199A Expired - Fee Related JP5101346B2 (en) | 2008-03-05 | 2008-03-05 | Exhaust gas purification catalyst and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5101346B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2465047C1 (en) * | 2011-07-29 | 2012-10-27 | Федеральное государственное бюджетное учреждение науки Институт химии Дальневосточного отделения Российской академии наук (ИХ ДВО РАН) | Method of making ice exhaust gas cleaning catalyst |
| CN104226306A (en) * | 2014-10-14 | 2014-12-24 | 北京恒泰实达科技股份有限公司 | Catalyst for oxidizing and eliminating formaldehyde at room temperature and preparation method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103648195B (en) * | 2013-11-29 | 2015-07-22 | 合兴集团汽车电子有限公司 | Manufacturing method of electric heating wire used for heating exhaust pipe |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6193836A (en) * | 1984-10-16 | 1986-05-12 | Nippon Shokubai Kagaku Kogyo Co Ltd | Preparation of catalyst |
| JP2003334457A (en) * | 2002-05-20 | 2003-11-25 | Denso Corp | Catalyst body and its manufacturing method |
| JP2005279533A (en) * | 2004-03-30 | 2005-10-13 | Honda Motor Co Ltd | Exhaust gas cleaning catalyst |
| JP2006068665A (en) * | 2004-09-03 | 2006-03-16 | Toyota Motor Corp | Method for producing catalyst for cleaning exhaust gas and catalyst for cleaning exhaust gas |
-
2008
- 2008-03-05 JP JP2008054199A patent/JP5101346B2/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6193836A (en) * | 1984-10-16 | 1986-05-12 | Nippon Shokubai Kagaku Kogyo Co Ltd | Preparation of catalyst |
| JP2003334457A (en) * | 2002-05-20 | 2003-11-25 | Denso Corp | Catalyst body and its manufacturing method |
| JP2005279533A (en) * | 2004-03-30 | 2005-10-13 | Honda Motor Co Ltd | Exhaust gas cleaning catalyst |
| JP2006068665A (en) * | 2004-09-03 | 2006-03-16 | Toyota Motor Corp | Method for producing catalyst for cleaning exhaust gas and catalyst for cleaning exhaust gas |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2465047C1 (en) * | 2011-07-29 | 2012-10-27 | Федеральное государственное бюджетное учреждение науки Институт химии Дальневосточного отделения Российской академии наук (ИХ ДВО РАН) | Method of making ice exhaust gas cleaning catalyst |
| CN104226306A (en) * | 2014-10-14 | 2014-12-24 | 北京恒泰实达科技股份有限公司 | Catalyst for oxidizing and eliminating formaldehyde at room temperature and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5101346B2 (en) | 2012-12-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2006030763A1 (en) | Cerium-zirconium-base composite oxide, process for producing the same, oxygen storage/release material using said cerium-zirconium-base composite oxide, exhaust gas purification catalyst, and exhaust gas purification method | |
| EP2703357A1 (en) | Layered complex oxide, oxidation catalyst and diesel particulate filter | |
| JP2010099638A (en) | Catalyst, catalyst for purifying exhaust gas, and method for manufacturing the catalyst | |
| JP2008136951A (en) | Composite oxide for exhaust gas cleaning catalyst, exhaust gas cleaning catalyst, and diesel exhaust gas purifying filter | |
| JP5119508B2 (en) | PM combustion oxidation catalyst, diesel engine exhaust gas purification method, filter and purification apparatus using the same | |
| WO2017073527A1 (en) | Exhaust gas purifying catalyst and method for producing same, and exhaust gas purification device using same | |
| JP4831753B2 (en) | Exhaust gas purification catalyst | |
| JP5101346B2 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JP2010069471A (en) | Compound oxide catalyst for burning pm, slurry prepared by using the same, and filter for cleaning exhaust gas | |
| JP2013166130A (en) | Exhaust gas cleaning three way catalyst | |
| JP2007105632A (en) | Exhaust gas cleaning catalyst | |
| JP2002204955A (en) | Catalyst for exhaust gas cleaning | |
| JP2005254047A (en) | Exhaust emission control catalyst, metal oxide particle, and production method thereof | |
| JPWO2018123862A1 (en) | Exhaust gas purification catalyst | |
| JPWO2018123863A1 (en) | Delafossite-type oxide for exhaust gas purification catalyst and exhaust gas purification catalyst using the same | |
| JP2011016090A (en) | Exhaust gas cleaning catalyst and method of manufacturing the same | |
| JP2011189306A (en) | Catalyst for cleaning exhaust gas | |
| JP2008150264A (en) | Ceria-zirconia-based compound oxide and its manufacturing method | |
| JP6077367B2 (en) | Exhaust gas purification catalyst | |
| JP2006035018A (en) | Carrier for catalyst and catalyst using the same | |
| JP2009142789A (en) | Catalytic carrier for cleaning exhaust gas, its manufacturing method, catalyst for cleaning exhaust gas and honeycomb catalyst structure for cleaning exhaust gas | |
| JP5030573B2 (en) | Composite oxide powder and method for producing the same | |
| WO2010103669A1 (en) | Catalyst carrier for exhaust gas purification, process for production thereof, exhaust gas purification catalyst, and honeycomb catalyst structure for exhaust gas purification | |
| WO2015173880A1 (en) | Hydrogen-generating catalyst, and exhaust gas purification catalyst | |
| JP3309711B2 (en) | Exhaust gas purification catalyst and method for producing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20110304 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110304 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20120606 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120612 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120810 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20120904 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20120926 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20151005 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 5101346 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| LAPS | Cancellation because of no payment of annual fees |