JPH04180836A - Exhaust gas purifying catalyst - Google Patents
Exhaust gas purifying catalystInfo
- Publication number
- JPH04180836A JPH04180836A JP2308631A JP30863190A JPH04180836A JP H04180836 A JPH04180836 A JP H04180836A JP 2308631 A JP2308631 A JP 2308631A JP 30863190 A JP30863190 A JP 30863190A JP H04180836 A JPH04180836 A JP H04180836A
- Authority
- JP
- Japan
- Prior art keywords
- zeolite
- catalyst
- exhaust gas
- ion exchange
- dealuminized
- 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
- 239000003054 catalyst Substances 0.000 title claims abstract description 34
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000010457 zeolite Substances 0.000 claims abstract description 43
- 229910021536 Zeolite Inorganic materials 0.000 claims abstract description 42
- 238000005342 ion exchange Methods 0.000 claims abstract description 13
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 7
- 239000010941 cobalt Substances 0.000 claims abstract description 7
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000000746 purification Methods 0.000 claims description 9
- 239000000843 powder Substances 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 10
- 238000010335 hydrothermal treatment Methods 0.000 abstract description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 abstract description 4
- 239000011248 coating agent Substances 0.000 abstract description 3
- 239000011247 coating layer Substances 0.000 abstract description 3
- 238000000576 coating method Methods 0.000 abstract description 3
- 239000002002 slurry Substances 0.000 abstract description 3
- 238000009835 boiling Methods 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 abstract description 2
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 25
- 239000010949 copper Substances 0.000 description 15
- 239000007789 gas Substances 0.000 description 13
- 239000000446 fuel Substances 0.000 description 10
- 230000007423 decrease Effects 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000010410 layer Substances 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 229910052802 copper Inorganic materials 0.000 description 4
- 229910052878 cordierite Inorganic materials 0.000 description 4
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000010948 rhodium Substances 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 3
- 230000001603 reducing effect Effects 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 229940011182 cobalt acetate Drugs 0.000 description 2
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- -1 tetrapropylammonium ions Chemical class 0.000 description 2
- LPSKDVINWQNWFE-UHFFFAOYSA-M tetrapropylazanium;hydroxide Chemical compound [OH-].CCC[N+](CCC)(CCC)CCC LPSKDVINWQNWFE-UHFFFAOYSA-M 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- RZZPDXZPRHQOCG-OJAKKHQRSA-O CDP-choline(1+) Chemical compound O[C@@H]1[C@H](O)[C@@H](COP(O)(=O)OP(O)(=O)OCC[N+](C)(C)C)O[C@H]1N1C(=O)N=C(N)C=C1 RZZPDXZPRHQOCG-OJAKKHQRSA-O 0.000 description 1
- 101100348017 Drosophila melanogaster Nazo gene Proteins 0.000 description 1
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 239000006255 coating slurry Substances 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001429 cobalt ion Inorganic materials 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- 229940044175 cobalt sulfate Drugs 0.000 description 1
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 1
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical group [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 description 1
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000001420 photoelectron spectroscopy Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
【発明の詳細な説明】 （産業上の利用分野〕 。[Detailed description of the invention] (Industrial application field).
本発明は、自動車の排気ガス浄化用触媒、更に詳しくは
空燃比がリーン側の酸素過剰雰囲気においてもＮＯｘを
高率で浄化でき、６００°Ｃ以上の高温耐久後のＮＯｘ
浄化率も良好な排気ガス浄化用触媒に関する。The present invention is a catalyst for purifying automobile exhaust gas, and more specifically, it is capable of purifying NOx at a high rate even in an oxygen-rich atmosphere with a lean air-fuel ratio, and is capable of purifying NOx after high-temperature durability at 600°C or higher.
The present invention relates to an exhaust gas purifying catalyst that also has a good purification rate.
［従来の技術］
自動車の排気ガス浄化用触媒として、ＣＯ（−酸化炭素
）及びＨＣ（、炭化水素）の酸化と、Ｎ０ｘ（窒素酸化
物）の還元を同時に行なう三元触媒が汎用されている。[Prior art] Three-way catalysts that simultaneously oxidize CO (-carbon oxides) and HC (hydrocarbons) and reduce NOx (nitrogen oxides) are widely used as catalysts for purifying automobile exhaust gas. .
この触媒は基本的にはコージェライト等の耐火性担体に
γ−アルミナスラリーをウォッシュコートし、焼成した
後、パラジウム、白金、ロジウム等の触媒活性成分を担
持させたものである。This catalyst is basically a refractory carrier such as cordierite wash-coated with γ-alumina slurry, fired, and then supported with a catalytically active component such as palladium, platinum, or rhodium.
ところで、こうした触媒の排気ガス浄化性能は、エンジ
ンの設定空燃比に大きく左右される。即ち、空燃比が太
きいリーン側（希薄混合気）では燃焼後も酸素の量が多
くなり、酸化作用が活発に、還元作用が不活発になる。Incidentally, the exhaust gas purification performance of such a catalyst is greatly influenced by the set air-fuel ratio of the engine. That is, on the lean side (lean mixture) where the air-fuel ratio is large, the amount of oxygen is large even after combustion, and the oxidizing action becomes active while the reducing action becomes inactive.
これとは逆に、空燃比の小さいリッチ側では酸化作用が
不活発に、還元作用が活発になる。この酸化と還元のバ
ランスがとれるストイキ（理論空燃比Ａ／Ｆ＝１４．６
付近）で三元触媒が最も有効に働く。On the contrary, on the rich side where the air-fuel ratio is small, the oxidizing action becomes inactive and the reducing action becomes active. The stoichiometric air-fuel ratio that balances this oxidation and reduction (theoretical air-fuel ratio A/F = 14.6
The three-way catalyst works most effectively in the vicinity).
従って、三元触媒を用いる排気ガス浄化装置を取付けた
自動車では、排気系の酸素濃度を検出して混合気をスト
イキに近ずけるようフィードバック制御が行なわれてい
る。Therefore, in automobiles equipped with exhaust gas purification devices using three-way catalysts, feedback control is performed to detect the oxygen concentration in the exhaust system and bring the air-fuel mixture close to stoichiometric.
一方、自動車においては低燃費化も要請されており、そ
のためには、通常走行時なるべく希薄混合気を燃焼させ
ればよいことが知られている。しかしそうすると空燃比
がリーン側の酸素過剰雰囲気となって、排気ガス中の有
害成分のうちｎｃ、 ｃ。On the other hand, there is also a demand for lower fuel consumption in automobiles, and it is known that for this purpose, it is sufficient to burn as lean an air-fuel mixture as possible during normal driving. However, if this is done, the air-fuel ratio will be on the lean side, resulting in an atmosphere with excess oxygen, and among the harmful components in the exhaust gas, nc and c.
は酸化除去できても、ＮＯｘは触媒床に吸着した酸素に
よって活性金属との接触が妨げられるために、還元除去
できないという問題があった。そこでリーン側でもＮＯ
ｘを還元できる触媒として、担体上にゼオライトコート
層を形成させ、そこにイオン交換によりＣｕを担持させ
たＣｕ／ゼオライト触媒が特開昭６０−１２５２５０号
公報に提案されている。There is a problem in that even though NOx can be removed by oxidation, NOx cannot be removed by reduction because the oxygen adsorbed on the catalyst bed prevents contact with the active metal. Therefore, even on the lean side, NO
As a catalyst capable of reducing x, a Cu/zeolite catalyst is proposed in JP-A-60-125250, in which a zeolite coat layer is formed on a carrier and Cu is supported thereon by ion exchange.
しかしながら、このＣｕ／ゼオライト触媒は初期活性に
優れてはいても遠からず活性が低下するため実用に供し
得ないという問題があった。これは、Ｃｕ／ゼオライト
触媒を高い温度で熱処理するほど著しい活性低下が見ら
れることから、ゼオライトの耐熱性の悪さに起因してい
るものと思われる。However, although this Cu/zeolite catalyst has excellent initial activity, there is a problem in that it cannot be put to practical use because the activity soon decreases. This is thought to be due to the poor heat resistance of zeolite, since the more the Cu/zeolite catalyst is heat-treated at a higher temperature, the more the activity decreases more markedly.
そこで、本発明者らは先きに高温排気ガス中で使用して
も活性低下が実用上許容し得、リーン側のＮＯｘでも効
率よく浄化できる触媒を提案した（特開平２−１２６９
４１号公報参照）。この触媒は耐火性担体上に表面を脱
Ａｌ化したゼオライトからなるコート層が形成され、そ
こにＣｕがイオン交換担持されたものである。Therefore, the present inventors have previously proposed a catalyst that can practically tolerate a decrease in activity even when used in high-temperature exhaust gas, and can efficiently purify NOx even on the lean side (Japanese Patent Application Laid-Open No. 2-1269
(See Publication No. 41). In this catalyst, a coat layer made of zeolite whose surface has been de-aluminum-treated is formed on a refractory carrier, and Cu is supported thereon by ion exchange.
しかしながら、このＣｕがイオン交換された脱Ａｌ化ゼ
オライトコート層を有する触媒も、６００°Ｃ以上の高
温では担持された銅が移動して活性点から外れるためか
、高温で耐久試験した後のＮＯｘ浄化率が未だ十分でな
いという問題があった。However, even with this catalyst having a de-alinated zeolite coat layer in which Cu is ion-exchanged, NO There was a problem that the purification rate was still not sufficient.
本発明は上記問題を解決する目的でなされたものであり
、その解決しようとする課題は、６００°Ｃ以上の高温
の耐久後においても大きな活性低下を起すことなく、リ
ーン側のＮＯｘをも高率に浄化できる排気ガス浄化用触
媒を提供することにある。The present invention was made for the purpose of solving the above problem, and the problem to be solved is to increase NOx on the lean side without causing a large decrease in activity even after endurance at high temperatures of 600°C or more. An object of the present invention is to provide a catalyst for purifying exhaust gas that can purify exhaust gas at a high rate.
上記課題を解決できる本発明の排気ガス浄化用触媒は、
耐火性担体上に表面を脱Ａｌ化したゼオライトからなる
コート層を形成して成り、そのコート層にコバルトがイ
オン交換担持されて成る。The exhaust gas purifying catalyst of the present invention that can solve the above problems is as follows:
A coat layer made of zeolite whose surface has been de-aluminum-treated is formed on a refractory carrier, and cobalt is ion-exchanged and supported on the coat layer.
即ち、本発明は従来のＣｕ／ゼオライト触媒において、
通常のゼオライトの代りに、脱Ａｌ化したゼオライトを
使用し、かつＣｕに代えてコバルト（ＣＯ）を担持させ
て成る。That is, in the present invention, in the conventional Cu/zeolite catalyst,
Instead of normal zeolite, deal-aluminum zeolite is used and cobalt (CO) is supported instead of Cu.
脱Ａｌ化の手段としては、ゼオライト粒子への塩酸での
煮沸処理、あるいは水蒸気を多量に含む雰囲気中で加熱
する水熱処理などを挙げることができる。この場合ゼオ
ライト粒子の表面から徐々にＡＩが脱離していくが、脱
Ａｌ化をゼオライト内部まで完全に行なうことは、触媒
の活性低下をもたらすので避けるべきである。脱Ａｌ化
は、Ａｌ／Ｓｉ比が５０〜２５０となる程度に行なうの
が好ましい。Examples of means for removing Al include boiling treatment of zeolite particles with hydrochloric acid, hydrothermal treatment of heating in an atmosphere containing a large amount of water vapor, and the like. In this case, AI is gradually desorbed from the surface of the zeolite particles, but it should be avoided to completely remove Al into the interior of the zeolite, as this will result in a decrease in the activity of the catalyst. It is preferable to carry out de-Alization to such an extent that the Al/Si ratio is 50 to 250.
脱Ａｌ化するゼオライトとしては、特に限定されないが
、ゼオライトの種類によって脱Ａｌ化後の構造安定性、
浄化性能等に差がみられるので、必要とする特性に応じ
て適当に選択するのがよい。好ましいものとしては、調
製過程においてテトラプロピルアンモニウムイオンを取
り込ませ、それを焼成除去して合成されるＺＳＭ−５型
ゼオライト、或はそれと同程度の孔径、５ｉ０２／ Ａ
ｌ２Ｏ３比を持つものが挙げられる。The zeolite to be dealt with is not particularly limited, but the structural stability after dealing with aluminum depends on the type of zeolite.
Since there are differences in purification performance, etc., it is best to select appropriately depending on the required characteristics. Preferably, ZSM-5 type zeolite is synthesized by incorporating tetrapropylammonium ions in the preparation process and removing them by calcination, or 5i02/A with a pore size comparable to that of ZSM-5 type zeolite.
Examples include those having a l2O3 ratio.
本触媒は、上記脱Ａｌ化ゼオライトからスラリーを調製
し、それを耐火性担体にウォッシュコートし焼成した後
、イオン交換によってＣＯを担持させることにより製造
することができる。或は予め脱Ａｌ化ゼオライトにＣｏ
イオン交換処理を施し、それをウォッシュコートして製
造してもよい。上記イオン交換は、ゼオライト中に補正
電荷として含まれて↓）る。Ｎａ”（ばか若干のＨ゛等
）をＣＯイオンに置換させることであり、硫酸コバルト
、硝酸コバルトなどの鉱酸塩または酢酸コバルトなどの
有機酸塩を溶解した水溶液中にゼオライトを浸漬するな
どの通常の方法によって行なわれる。ＣＯイオン交換率
は、それが高いほどＮＯｘ分解活性が高いので、少なく
とも５０％以上、好ましくは８０〜１５０％であるのが
良い。The present catalyst can be produced by preparing a slurry from the above dealinized zeolite, wash-coating it on a refractory carrier, calcining it, and then supporting CO by ion exchange. Alternatively, Co
It may also be manufactured by subjecting it to ion exchange treatment and then washcoating it. The above ion exchange is included in the zeolite as a correction charge ↓). The process involves substituting CO ions for Na'' (or some H'', etc.), and zeolite is immersed in an aqueous solution containing mineral acid salts such as cobalt sulfate and cobalt nitrate, or organic acid salts such as cobalt acetate. The CO ion exchange rate is preferably at least 50%, preferably 80 to 150%, because the higher the CO ion exchange rate, the higher the NOx decomposition activity.
［作用］
ゼオライトを脱Ａｌ化すると、ゼオライトの構造は、よ
り熱に対し安定な構造へと変わる。[Function] When the zeolite is de-alinated, the structure of the zeolite changes to a structure that is more stable against heat.
こうして耐熱性が一段と向上した脱Ａｌ化ゼオライトで
担体上にコート層を形成し、それにＣｏをイオン交換担
持させた排気ガス浄化用触媒は、例えば６００°Ｃ以上
の高温で耐久試験した後でもコバルトが活性点から移動
しないため、実用上問題となるような劣化を起すことは
なく、高い浄化性能を維持する。In this way, an exhaust gas purification catalyst in which a coating layer is formed on a carrier using dealinated zeolite, which has further improved heat resistance, and Co is ion-exchanged on the carrier, even after a durability test at a high temperature of 600°C or higher, cobalt remains. does not move from the active site, so it does not cause deterioration that would pose a practical problem and maintains high purification performance.
なお脱Ａｌ化ゼオライトは自身が有する細孔にＩＣ１Ｃ
Ｏ及びＮＯｘを補足し、ＣｏはＣｏ −ＮＯｘ相互間及
びＨＣ−ＮＯｘ相互間の酸化還元反応を促進する触媒と
して作用する。Note that de-aluminum zeolite has IC1C in its own pores.
Co supplements O and NOx, and Co acts as a catalyst that promotes redox reactions between Co and NOx and between HC and NOx.
以下、実施例によって本発明を更に詳しく説明するが、
本発明をこれらの実施例に限定するものでないことはい
うまでもない。Hereinafter, the present invention will be explained in more detail with reference to Examples.
It goes without saying that the present invention is not limited to these examples.
；Ａｌ ゼオ−イトのＬｊ告
シリカゾル（３０重量％５ｉＯ７）、アルミン酸ナトリ
ウム溶液（１，５ＮａｚＯ／ＡｌｚＯｓ）、水及びＴＰ
ＡＯ）Ｉｉ液〔１モル／１．水酸化テトラプロピルアン
モニウム： （ＣＪ７）Ｊ” ・ＯＨ−溶液〕を最終的
に６０５ｉｆｔ・＾ｈＯｉ ’ ２．５ ＮａｚＯ・２
．９ ＴＰＡＯＨ・５５０ ＨｚＯとなるように混合し
て、室温でＩＯ分間程度攬袢混合した。; Al zeolite Lj-specific silica sol (30% by weight 5iO7), sodium aluminate solution (1,5NazO/AlzOs), water and TP
AO) Ii liquid [1 mol/1. Tetrapropylammonium hydroxide: (CJ7)J'' ・OH-solution] was finally converted to 605ift・^hOi ' 2.5 NazO・2
．． 9 TPAOH at 550 HzO, and mixed for about 10 minutes at room temperature.
得られた混合物を１６０’ｃで１０時間焼成してＺＳＭ
−５型ゼオライトを得た。このゼオライトを、水蒸気が
多量に含まれている雰囲気中にて５５０″Ｃで水熱処理
し、脱Ａｌ化ゼオライトを製造した。その際、水熱処理
時間を２０．４０．６０．１８０及び３００時間とし、
ＡＩ含有率が様々の脱Ａｌ化ゼオライトを製造した。処
理時間とＳｉｎｇ／ Ａｌ ｚＯｓ （モル比）の関係
を第１表に示す。The resulting mixture was baked at 160'c for 10 hours to form a ZSM
-5 type zeolite was obtained. This zeolite was hydrothermally treated at 550"C in an atmosphere containing a large amount of water vapor to produce de-alinated zeolite. At that time, the hydrothermal treatment time was 20, 40, 60, 180 and 300 hours. ,
De-Alized zeolites with various AI contents were produced. Table 1 shows the relationship between treatment time and Sing/Al zOs (molar ratio).
第１表から明らかなように、水熱処理時間が長いほど脱
Ａｌ化が進む。水熱処理をしたゼオライトについて、一
定速度で表面をエツジングするＥＳＣ＾（光電子分光分
析）による表面分析を行ない、Ａ１を認めるに至るまで
のエツジング時間を調べた。As is clear from Table 1, the longer the hydrothermal treatment time, the more de-Alization progresses. The surface of the hydrothermally treated zeolite was analyzed by ESC^ (photoelectron spectroscopy) in which the surface was etched at a constant rate, and the etching time until A1 was recognized was investigated.
その結果を水熱処理時間の異なるゼオライトごとに第１
図に示す。第１図の結果から水熱処理時間によって脱Ａ
ｌ化をある程度制御できることがわかる。The results are summarized as follows for each zeolite with different hydrothermal treatment times.
As shown in the figure. From the results shown in Figure 1, it is possible to remove A by changing the hydrothermal treatment time.
It can be seen that the lization can be controlled to some extent.
実１副ＩＨユ±
前記参考０例で得た脱Ａ１ゼオライト粉末に０．２モル
／ｌ酢酸コバルト水溶液を用いて、コバルトイオン交換
を行なった。Actual 1 Secondary IH Unit Cobalt ion exchange was performed on the A1-depleted zeolite powder obtained in Reference Example 0 using a 0.2 mol/l cobalt acetate aqueous solution.
上で得た実施例１〜４のコバルトイオン交換した脱ＡＩ
ゼオライトをゼオライト５０重量部、シリカゾル（２０
重量％５ｉ（ｈ）７０重量部、水２０重量部を混合攪拌
し、コーティングスラリーを得た。このコート液を用い
て、第２図に示すような３０ｍ＋ｎφ×５０ｍｍＬのコ
ージェライトハニカムテストピースにウォッシュコート
しく２００ｇ／モノリスＩｆ）、５００°Ｃで３時間空
気中で焼成し、実施例１〜４の触媒を得た。Cobalt ion-exchanged de-AI of Examples 1 to 4 obtained above
Zeolite was mixed with 50 parts by weight of zeolite and silica sol (20 parts by weight).
70 parts by weight of 5i(h) and 20 parts by weight of water were mixed and stirred to obtain a coating slurry. Using this coating liquid, a cordierite honeycomb test piece of 30 m + nφ x 50 mm L as shown in Fig. 2 was wash coated (200 g/monolith If) and baked in air at 500°C for 3 hours. A catalyst was obtained.
を較班土
水熱処理していないゼオライト粉末に、０．２Ｍ酢酸コ
バルト水溶液を用いて、コバルトをイオン交換（Ｃｏ
２．７９重量％）した粉末を用いた以外は、実施例と同
じようにして比較例１の触媒を製造した。Cobalt was ion-exchanged (Co
A catalyst of Comparative Example 1 was produced in the same manner as in the Example except that a powder containing 2.79% by weight) was used.
ｌ較■呈
実施例と同様に４０分間水熱処理した脱＾１ゼオライト
に、０．２Ｍ酢酸銅アンミン水溶液を用いて、銅をイオ
ン交換した比較例２の触媒を製造した。Comparative Example 2 A catalyst of Comparative Example 2 was prepared by ion-exchanging copper by using a 0.2M aqueous copper ammine acetate solution on de^1 zeolite which had been hydrothermally treated for 40 minutes in the same manner as in the Comparative Example.
ル較桝主
活性アルミナ１００部、アルミナゾル（１０重量％＾ｔ
、ｏｓ）７０部、純水５０部及び４０重量％硝酸アルミ
ニウム水溶液１５部（部数はすべて重量基準）を混合攪
拌してウォッシュコートスラリーを調製した。100 parts of activated alumina, alumina sol (10% by weight)
.
これを実施例１で用いたのと同しコージェライト質モノ
リステストピースにウォッシュコートしく１２ｈ／モノ
リス構造体Ｉｆ）、７００°Ｃで１時間焼成することに
よりＴ−アルミナコート担体を製造した。This was wash-coated on the same cordierite monolith test piece used in Example 1 for 12 hours/monolith structure If) and fired at 700°C for 1 hour to produce a T-alumina coated carrier.
別に、ジニトロジアミン白金［Ｐｔ （ＮＨ３） ３
（ＮＯ２） ６ ）水溶液とへキサニトロロジウム酸ア
ンモニウム〔（ＮＨ４） ：ｌ・Ｒｈ （ＮＯ□）６〕
水溶液をＰｔ／Ｒｈ＝５となるように混合し、貴金属担
持液を調製した。この液に上記Ｔ−アルミナコート担体
を浸漬して１時間放置した後、引き上げて余分な水分を
吹き払ってから２５０°Ｃで１時間焼成し、担体１！当
りｐｔ及びＲｈを夫々１．５ｇ及び０．３ｇ担持した触
媒を製造した。Separately, dinitrodiamine platinum [Pt (NH3) 3
(NO2) 6) Aqueous solution and ammonium hexanitrorhodate [(NH4) :l・Rh (NO□)6]
The aqueous solutions were mixed so that Pt/Rh=5 to prepare a noble metal supporting solution. The T-alumina coated carrier was immersed in this solution and left for 1 hour, then pulled out, the excess water was blown off, and baked at 250°C for 1 hour. Catalysts each carrying 1.5 g and 0.3 g of PT and Rh, respectively, were produced.
上で得た実施例１〜４及び比較例１〜３の触媒を第３表
に示す。Table 3 shows the catalysts of Examples 1 to 4 and Comparative Examples 1 to 3 obtained above.
以下余白
第３表に示した実施例１〜４及び比較例１〜３の触媒の
触媒活性試験を以下の条件で行なった。Catalytic activity tests were conducted on the catalysts of Examples 1 to 4 and Comparative Examples 1 to 3 shown in Table 3 below under the following conditions.
耐久条件
８００°ＣＸ５時間、Ａ／Ｆ＝１８相当のモデルガス、
８．０＝１０％、Ｓν＝ ｉｏ、 ｏｏｏ時間−１且儀
条件
Ａ／Ｆ＝１８、ＬＯ−１０％、Ｓν＝ ６０．０００時
間−１１、入りガス温度５００°Ｃの定常評価
結果を第４表に示す。Durability conditions: 800°C x 5 hours, model gas equivalent to A/F = 18,
8.0 = 10%, Sν = io, ooo time-1 and operating conditions A/F = 18, LO-10%, Sν = 60.000 hours-11, inlet gas temperature 500°C. It is shown in Table 4.
第４表の結果から、脱Ａｌ化により、Ｃｏ／ゼオライト
触媒の耐熱性が向上していることがわかる。From the results in Table 4, it can be seen that the heat resistance of the Co/zeolite catalyst is improved by de-Alization.
また、水熱処理時間により、浄化率に差が認められるが
、これは、脱Ａｌ化の進み具合いに基づくものである。Furthermore, there is a difference in the purification rate depending on the hydrothermal treatment time, but this is based on the progress of de-Alization.
即ち、ゼオライト粒子の内部まで脱ＡＩされ、ＳｉＯ□
／Ａ１．０３＝２９０であれば、ＡＩが少なくなり、活
性点が殆ど無くなって触媒活性が低下するものと思われ
る。That is, AI is removed to the inside of the zeolite particles, and SiO□
/A1.03=290, it is thought that the amount of AI decreases and there are almost no active sites, resulting in a decrease in catalytic activity.
また、脱Ａ１ゼオライトとＣｕとの組み合せに比べても
、Ｃｏを用いたことにより、耐久性の向上が認められる
。これは、ＣＯの方がＣｕよりも熱に対して強いことに
起因するものと思われる。Furthermore, compared to the combination of Al-free zeolite and Cu, the use of Co has improved durability. This seems to be due to the fact that CO is more resistant to heat than Cu.
イオン交換で、Ｃｕ、 Ｃｏを担持しており、Ｃｕの場
合、高温（６００℃以上）では、Ｃｕ”が移動しやすい
ため、ゼオライト内部から出てしまうため、耐久後の活
性低下が大きい。これに対してＣＯは移動しにくく、活
性サイトにいるため、耐久後活性が高いことがわかる。Cu and Co are supported through ion exchange, and in the case of Cu, at high temperatures (above 600°C), Cu' moves easily and comes out from inside the zeolite, resulting in a significant decrease in activity after durability. On the other hand, CO is difficult to move and is located at the active site, so it can be seen that the activity after durability is high.
したがって、構造安定性と触媒活性とを両立させる最適
脱ＡＩ化率が存在し、上記処理で言えば２０〜６０時間
が望ましい。Therefore, there is an optimum de-Alization rate that achieves both structural stability and catalytic activity, and in terms of the above treatment, 20 to 60 hours is desirable.
第１図は一例のゼオライトの水熱処理時間とＡＩを確認
できるＥＳＣＡのエツジング時間との関係を表わすグラ
フ図であり：
第２図は実施例で使用したコージェライト質モノリステ
ストピースを示す概略斜視図である。Figure 1 is a graph showing the relationship between the hydrothermal treatment time of an example of zeolite and the etching time of ESCA that can confirm AI; Figure 2 is a schematic perspective view showing the cordierite monolith test piece used in the example. It is.
Claims (1)
ライト粉末から成るコート層を形成して成り、該コート
層にコバルトがイオン交換担持されていることを特徴と
する排気ガス浄化用触媒。1. 1. A catalyst for exhaust gas purification, comprising a refractory carrier formed with a coat layer made of zeolite powder whose surface has been dealuminated, and cobalt being supported by ion exchange on the coat layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2308631A JPH04180836A (en) | 1990-11-16 | 1990-11-16 | Exhaust gas purifying catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2308631A JPH04180836A (en) | 1990-11-16 | 1990-11-16 | Exhaust gas purifying catalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04180836A true JPH04180836A (en) | 1992-06-29 |
Family
ID=17983377
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2308631A Pending JPH04180836A (en) | 1990-11-16 | 1990-11-16 | Exhaust gas purifying catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04180836A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015535800A (en) * | 2012-09-28 | 2015-12-17 | パシフィック インダストリアル デベロップメント コーポレイション | Method for preparing STT-type zeolite for use as a catalyst in selective catalytic reduction reaction |
-
1990
- 1990-11-16 JP JP2308631A patent/JPH04180836A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015535800A (en) * | 2012-09-28 | 2015-12-17 | パシフィック インダストリアル デベロップメント コーポレイション | Method for preparing STT-type zeolite for use as a catalyst in selective catalytic reduction reaction |
| US10137411B2 (en) | 2012-09-28 | 2018-11-27 | Pacific Industrial Development Corporation | Method of preparing an STT-type zeolite for use as a catalyst in selective catalytic reduction reactions |
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