JPH0557024B2 - - Google Patents
Info
- Publication number
- JPH0557024B2 JPH0557024B2 JP60121835A JP12183585A JPH0557024B2 JP H0557024 B2 JPH0557024 B2 JP H0557024B2 JP 60121835 A JP60121835 A JP 60121835A JP 12183585 A JP12183585 A JP 12183585A JP H0557024 B2 JPH0557024 B2 JP H0557024B2
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- exhaust gas
- temperature
- present
- gas purification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000003054 catalyst Substances 0.000 claims description 19
- 238000000746 purification Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910002367 SrTiO Inorganic materials 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910002514 Co–Co Inorganic materials 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- 229910002544 Fe-Cr Inorganic materials 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000005090 crystal field Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010285 flame spraying Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 238000007751 thermal spraying Methods 0.000 description 1
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Description
産業上の利用分野
本発明は、各種の燃焼機器から排出される排気
ガス中の有害ガス成分を浄化処理する触媒に関す
るものである。
従来の技術
各種の燃焼機器（ガス・石油ストーブ、ボイラ
ー、自動車エンジンなど）から排出される排気ガ
スの主要な有害ガス成分であるCOとNOxを、同
時に浄化処理する触媒として、ペロブスカイト型
複合酸化物であるSr1+X/2La1-x/2Co1-xMexO3（Me
＝Fe、Mn、Cr、Ｖから選ぶ１種の元素、Ｏ＜ｘ
＜１）と、SrMeO3（Me＝Ti、Zr、Hfから選ぶ
１種類の元素）からなる２成分系の物質が提案さ
れている。
発明が解決しようとする問題点
上記の触媒では500℃以下での触媒活性が低く、
適用温度は600℃以上と限定されていた。本発明
はかかる問題点を鑑みてなされたもので、触媒と
しての活性温度領域を400℃まで広げた排気ガス
浄化触媒を提供することを目的とする。
問題点を解決するための手段
本発明は一般式Ae1-zSrzCo1-xBexO3（Ae＝Nd
またはHo；Be＝Fe、Mn、Cr、Ｖから選ぶ少な
くとも一種の元素、Ｏ≦ｘ≦１、Ｏ≦ｚ≦１）で
表わされる酸化物とAB1-yAlyO3（Ａ＝Caまたは
Sr；Ｂ＝Ti、Zr、Hfから選ぶ一種の元素、Ｏ≦
ｙ≦１）で表わされる酸化物との混合物あるいは
混合焼結体から排気ガス浄化触媒を構成するもの
である。
作 用
ペロブスカイト型酸化物におけるCOの酸化反
応の触媒活性点はSr2+注入により生じるCo3+に
ある。
結晶場において、３ｄ電子軌道はt2gとegとい
う２つの電子軌道に分裂する。３価のコバルトで
はこの３ｄ軌道には６個の電子があり、分裂した
軌道への配列としては、（t2g 6，eg 0）と（t2g 4，eg
２）と言う２通りのはいり方があり、前者を低ス
ピン状態、後者を高スピン状態とよび、記号とし
てそれぞれCo〓，Co3+と表わす。そして、この
Co3+はSr2+が注入するに従い比率は多くなる。
そしてCOのＣに存在する孤立電子群は、触媒表
面に吸着するとCo3+の電子軌道の１つであるdz 2
に進入する。その時、同時にCo3+のt2g軌道にあ
つた電子はCOのπ*軌道に進入し、結果的にCOは
電子不足状態で（CO）2+となり、他方Co−Ｏ−
Coにあつた結合は、Co−CoとO2-に分離してし
まい、このO2-が（CO）2+と反応してCO2となる
のである。つまりCO酸化触媒としての活性度は
Co3+が多いほど高くなるのであり、
SrLaCoMeO3系よりもSrNdCoMeO3系や
SrHoCoMeO3系の方がCo3+の量が多く、触媒活
性は高くなり、その結果、触媒活性を持ち続けら
れる温度下限も400℃まで広げられたのである。
実施例
実施例 １
第１図および第２図に、本発明になる担持型触
媒体の特性を従来例と共に示す。Ho0.5Sr0.5Co0.7
Fe0.3O3を50mol％とCaHf0.8Al0.2O3を50mol％か
らなる２成分系の材料を200メツシユ以下粉末と
し、担体としてのFe−Cr系の耐熱金網（40メツ
シユ相当、φ24mm）に水素溶射により約100μmの
厚さに均一に付着させた。これに対し、従来例に
は、Sr0.65La0.35Co0.7Fe0.3O340mol％と
SrTiO360mol％からなる材料を用いた。
この触媒体を５枚重ねて石笑ガラス製の反応容
器内に設置し、電気炉で温度制御を行なつて活性
を測定した。反応ガスにはCO150ppm.，
NO250ppm.，N2残部からなる均一混合ガスを用
い、空間速度83000h-1で触媒層に供給した。第１
図にCO除去率、第３図にN2及びNO生成率をそ
れぞれ示した。図を見れば分かるように本実施例
のほうが従来例よりも活性は高く、より低温域か
ら排ガスの浄化能力を有すると言える。なお本実
施例ではAe1-zSrzCo1-xBexO3とAB1-yAlyO3とを
混合し、焼成したものを材料として用いたが、両
者の混合物を用いた場合にも、ほぼ同様の結果が
得られた。
実施例 ２
次に、セラミツク製担体に担持した場合の例を
示す。触媒成分は、Nd0.5Sr0.5Co0.5Fe0.5O3と
SrZr0.5Al0.5O3とをモル比0.65：0.35で混合したも
のを用いた。担体にはアルミナ製のハニカム成型
体（φ110mm×t10mm、３mmロセル、セル数約500）
を用いた。実施例及び従来例ともにこの担体表面
に水素炎溶射により触媒体を約200μmの厚さに付
着させたものを用いた。これらの触媒体１枚を市
販のポータブル型石油ストーブの燃焼筒の上部に
取り付け、触媒体通過後の排気ガス中のCO濃度
及びNOx（＝NO＋NO2）濃度を測定した。排気
ガス温度は約700℃である。その結果を表に示す。
ただし従来例にはSr0.65La0.35Co0.7Fe0.3O340mol
％とSrTiO360molからなる材料を用いた。
INDUSTRIAL APPLICATION FIELD The present invention relates to a catalyst that purifies harmful gas components in exhaust gas discharged from various combustion devices. Conventional technology Perovskite-type complex oxidation is used as a catalyst to simultaneously purify CO and NO x , which are the main harmful gas components of exhaust gas emitted from various combustion equipment (gas/oil stoves, boilers, automobile engines, etc.). Sr 1+X/2 La 1-x/2 Co 1-x Me x O 3 (Me
=One element selected from Fe, Mn, Cr, V, O<x
<1) and SrMeO 3 (Me = one type of element selected from Ti, Zr, and Hf) has been proposed. Problems to be solved by the invention The above catalyst has low catalytic activity at temperatures below 500°C.
The applicable temperature was limited to 600℃ or higher. The present invention was made in view of these problems, and an object of the present invention is to provide an exhaust gas purification catalyst whose active temperature range as a catalyst is expanded to 400°C. Means for Solving the Problems The present invention is based on the general formula Ae 1-z Sr z Co 1-x Be x O 3 (Ae=Nd
or Ho; Be=at least one element selected from Fe, Mn, Cr, and V, an oxide represented by O≦x≦1, O≦z≦1) and AB 1-y Al y O 3 (A=Ca or
Sr; B = an element selected from Ti, Zr, Hf, O≦
The exhaust gas purification catalyst is constructed from a mixture or a mixed sintered body with an oxide represented by y≦1). Effect The catalytic active site for the CO oxidation reaction in perovskite-type oxides is located in Co 3+ generated by Sr 2+ injection. In the crystal field, the 3d electron orbital splits into two electron orbitals, t 2g and e g . In trivalent cobalt, there are 6 electrons in this 3d orbital, and the arrangement into the split orbitals is (t 2g 6 , e g 0 ) and (t 2g 4 , e g
2 ) There are two ways of entry, the former is called a low spin state and the latter a high spin state, and are represented by the symbols Co〓 and Co 3+ , respectively. And this
The ratio of Co 3+ increases as Sr 2+ is injected.
When the lone electron group present in C of CO is adsorbed on the catalyst surface, it becomes d z 2 which is one of the electron orbitals of Co 3+ .
enter. At that time, the electrons that were in the t 2g orbit of Co 3+ enter the π * orbit of CO, and as a result, CO becomes (CO) 2+ in an electron-deficient state, while Co−O−
The bond that hits Co separates into Co-Co and O 2- , and this O 2- reacts with (CO) 2+ to form CO 2 . In other words, the activity as a CO oxidation catalyst is
The more Co 3+ there is, the higher it becomes.
SrNdCoMeO 3 series rather than SrLaCoMeO 3 series
The SrHoCoMeO 3 system has a higher amount of Co 3+ and has higher catalytic activity, and as a result, the lower temperature limit at which it can maintain catalytic activity has been extended to 400°C. Examples Example 1 FIGS. 1 and 2 show the characteristics of the supported catalyst according to the present invention together with a conventional example. Ho 0.5 Sr 0.5 Co 0.7
A two-component material consisting of 50 mol% Fe 0.3 O 3 and 50 mol% CaHf 0.8 Al 0.2 O 3 is powdered to less than 200 meshes, and hydrogen is added to Fe-Cr heat-resistant wire mesh (equivalent to 40 meshes, φ24 mm) as a carrier. It was deposited uniformly to a thickness of about 100 μm by thermal spraying. On the other hand, in the conventional example, Sr 0.65 La 0.35 Co 0.7 Fe 0.3 O 3 40mol%
A material consisting of 60 mol% SrTiO 3 was used. Five sheets of this catalyst were stacked and placed in a reaction vessel made of stone glass, and the temperature was controlled in an electric furnace to measure the activity. Reaction gas contains CO150ppm.
A homogeneous mixed gas consisting of 50 ppm of NO 2 and the remainder of N 2 was supplied to the catalyst layer at a space velocity of 83000 h -1 . 1st
The figure shows the CO removal rate, and Figure 3 shows the N 2 and NO production rates. As can be seen from the figure, the activity of this example is higher than that of the conventional example, and it can be said that it has the ability to purify exhaust gas from a lower temperature range. In this example, a mixture of Ae 1-z Sr z Co 1-x Be x O 3 and AB 1-y Al y O 3 and fired material was used as the material, but when a mixture of the two is used Almost similar results were obtained. Example 2 Next, an example will be shown in which it is supported on a ceramic carrier. The catalyst components are Nd 0.5 Sr 0.5 Co 0.5 Fe 0.5 O 3
A mixture of SrZr 0.5 Al 0.5 O 3 at a molar ratio of 0.65:0.35 was used. The carrier is an alumina honeycomb molded body (φ110mm x t10mm, 3mm cell, number of cells is approximately 500)
was used. In both the example and the conventional example, a catalyst having a thickness of about 200 μm was attached to the surface of this carrier by hydrogen flame spraying. One of these catalyst bodies was attached to the top of the combustion tube of a commercially available portable kerosene stove, and the CO concentration and NO x (=NO+NO 2 ) concentration in the exhaust gas after passing through the catalyst body were measured. Exhaust gas temperature is approximately 700℃. The results are shown in the table.
However, in the conventional example, Sr 0.65 La 0.35 Co 0.7 Fe 0.3 O 3 40mol
% and 60 mol of SrTiO 3 was used.
【表】
発明の効果
以上述べてきたように、触媒成分として従来の
SrLaCoO3系材料よりHoSrCoO3系やNdSrCoO3
系材料を用いるほうがCO酸化、NO2還元の触媒
活性は高くなる。[Table] Effects of the invention As stated above, conventional
HoSrCoO 3 and NdSrCoO 3 are better than SrLaCoO 3 based materials.
The catalytic activity for CO oxidation and NO 2 reduction will be higher when using such materials.
第１図は本発明の一実施例の排気ガス浄化触媒
の温度とCO除去率との関係図、第２図は従来例
の排気ガス浄化触媒の温度とCO除去率との関係
図、第３図は本発明及び従来例の排気ガス浄化触
媒の温度に対するNO生成率、N2生成率の関係図
である。
FIG. 1 is a relationship between the temperature and CO removal rate of an exhaust gas purification catalyst according to an embodiment of the present invention, FIG. 2 is a relationship between temperature and CO removal rate of a conventional exhaust gas purification catalyst, and FIG. The figure is a diagram showing the relationship between the NO production rate and the N 2 production rate with respect to the temperature of the exhaust gas purification catalyst of the present invention and the conventional example.
Claims (1)
Ho、0.3≦ｘ≦0.5、0.4≦ｚ≦0.6）で表わされる
酸化物と、AB1-yAlyO3（Ａ＝CaまたはSr：Ｂ＝
ZrまたはHf、0.1≦ｙ≦0.6）で表わされる酸化物
との混合物あるいは混合焼結体からなる排気ガス
浄化触媒。1 General formula Ae 1-z SrzCo 1-x Fe x O 3 (Ae=Nd or
Ho, 0.3≦x≦0.5, 0.4≦z≦0.6) and AB 1-y Al y O 3 (A=Ca or Sr:B=
An exhaust gas purification catalyst made of a mixture or mixed sintered body with an oxide represented by Zr or Hf (0.1≦y≦0.6).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60121835A JPS61283349A (en) | 1985-06-05 | 1985-06-05 | Catalyst for purifying exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60121835A JPS61283349A (en) | 1985-06-05 | 1985-06-05 | Catalyst for purifying exhaust gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61283349A JPS61283349A (en) | 1986-12-13 |
| JPH0557024B2 true JPH0557024B2 (en) | 1993-08-23 |
Family
ID=14821107
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60121835A Granted JPS61283349A (en) | 1985-06-05 | 1985-06-05 | Catalyst for purifying exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61283349A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63158130A (en) * | 1986-12-23 | 1988-07-01 | Tech Res Assoc Conduct Inorg Compo | Catalyst for purifying exhaust gas |
| DE102009000208A1 (en) * | 2009-01-14 | 2010-07-15 | Robert Bosch Gmbh | Structural element, preferably particle filter, particle sensor or waste gas catalyst for reducing penetration of ash melting during thermal loading of component, comprises coating contactable with burn exhaust gases |
| CN103041802B (en) * | 2013-01-02 | 2014-11-05 | 桂林理工大学 | Perovskite catalyst for automobile tail gas treatment and preparation method of perovskite catalyst |
-
1985
- 1985-06-05 JP JP60121835A patent/JPS61283349A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61283349A (en) | 1986-12-13 |
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