JPS5830338A - Waste gas purifying catalyst - Google Patents

Abstract

PURPOSE:To obtain a catalyst superior in low temp. activity, and high in durability, by adding titanium and potassium, and then a noble metal component to a carrier to prepare a catalyst for purifying an waste gas. CONSTITUTION:Titanium and potassium are first carried in a carrier, such as alumina or cordierite, of a catalyst for purifying the waste gas of an internal combustion engine, and then, a component of a noble metal, such as platinum, palladium, or rhodium are added to it, thus permitting low temp. activity of the catalyst to be enhanced without increasing the content of the noble metal and durability to be also raised.

Description

【発明の詳細な説明】 本発明は低温において優れた活性を示す内燃機関の排気
ガス浄化用触媒に関する。内燃機関、特に自動車の内燃
機関からの排ガス中に含１れる有害物質を除去または低
減するための浄化用触媒としては耐久性、浄化性におい
て極めてＭ；度な性能が要求されており従来自動車排気
ガス浄化用触媒にはα−アルミナ、γ−アルミナ等から
なる粒状担体又はハニカム状コージライト担体にアルミ
ナを被覆したモノリス担体などに白金、ロジウム、パラ
ジウム等の触媒活性金有する貴金属全単独又は組合せて
担持した触媒が使用されていることは既に知られている
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst for purifying exhaust gas of an internal combustion engine that exhibits excellent activity at low temperatures. As a purification catalyst for removing or reducing harmful substances contained in exhaust gas from internal combustion engines, especially automobile internal combustion engines, extremely high performance in terms of durability and purification performance is required, and conventional automobile exhaust For gas purification catalysts, a granular carrier made of α-alumina, γ-alumina, etc. or a monolithic carrier such as a honeycomb-shaped cordierite carrier coated with alumina, etc., and noble metals containing catalytically active gold such as platinum, rhodium, and palladium may be used alone or in combination. The use of supported catalysts is already known.

しかるに近年車輛の低燃費化が重要視され、これに伴な
い排ガスの温度が低下する傾向におり、低温活性に優れ
た触媒に対する要求が大きい。However, in recent years, emphasis has been placed on improving the fuel efficiency of vehicles, and as a result, the temperature of exhaust gas tends to decrease, and there is a strong demand for catalysts with excellent low-temperature activity.

本発明の目的はこのような要望に応えるために低温での
活性に優れると共に耐久性をも併せもつ触媒を提供せん
とするものである。An object of the present invention is to provide a catalyst that has excellent activity at low temperatures and is also durable in order to meet such demands.

本発明者等は貴金属の担持量を増すことなしに上記の目
的を達成し得る触媒を求めて研究金型ねた結果、第三成
分すなわちチタン、カリウムの添加によシ、それも貴金
属の担持に先立って添加することで貴金属の相持状態に
変化を与えることにより従来の触媒より低温における浄
化性能を向上せしめうろことを見出した。The present inventors conducted research in search of a catalyst that could achieve the above objectives without increasing the amount of precious metals supported. It has been found that by adding precious metals prior to the catalyst, the purification performance at low temperatures can be improved compared to conventional catalysts by changing the state of mutual attachment of precious metals.

本発明で用いる触媒担体としては従来使用されていたも
のが使用でき球状でもモノリスタイプのものでもよい。As the catalyst carrier used in the present invention, conventionally used catalyst carriers can be used, and they may be spherical or monolithic.

担体は材質的には特に限定されずアルミナ、コージェラ
イト等が用いられる。好１しくけアルミナ担体でα−１
γ−アルミナ等が使用される、 担持金属としては触媒活性を有する白金（１）ｔ）パラ
ジウム（Ｉ’ｄ＞ロジウム（Ｒｈ）等の霞金属が使用さ
れ、これら貴金属は単独又は混イすして前記の担体に担
持させる。貴金属は通常このＪ（１１の目的で使用され
る範囲の址で用いらｔ圭るが好剪しい担持量は触媒の容
喰に対しｐｔ　ｏ、ｉ〜２９／ｌ、　Ｐｄ０３１〜２２
μ、ｌＲｈ　（１０２〜０．２！ｌ’／ｌである。これ
らの担持金属を混合して用いる場付には例えばＰｔ１．
３５か’ｔ−Ｒｈ０．１５〕／ｌ、　　ＰｄＯ，８９／
ｌ−・■）ｈα０５り／を等の割合で使用する。本発明
においては触媒成分として上記貴金属のほかにこれら貴
金属の触媒活１７１°を持続させるための他の触媒成分
、例えｔ」：セリウム（Ｃｅ）等を担持させてもよい。The material of the carrier is not particularly limited, and alumina, cordierite, etc. are used. α-1 with a preferable alumina carrier
γ-alumina, etc. are used. As supporting metals, hazy metals such as platinum (1) t) palladium (I'd> rhodium (Rh)), which have catalytic activity, are used, and these noble metals may be used alone or in combination. The noble metal is usually supported on the above-mentioned carrier.Noble metals are usually used in the range used for the purpose of J (11), but the preferred supported amount is pt o, i ~ 29/l relative to the catalyst capacity. , Pd031-22
μ, lRh (102 to 0.2! l'/l. When using a mixture of these supported metals, for example, Pt1.
35?t-Rh0.15]/l, PdO, 89/
l-・■)hα05ri/ are used in the same proportions. In the present invention, in addition to the above-mentioned noble metals, other catalyst components such as cerium (Ce) may be supported to maintain the catalytic activity of these noble metals.

上記貴金属に先立って担持すべきチタン及びカリウムの
ｆｊｋは使用目的、担持する貴金属の種類に応じて適宜
変えられるが、チタン及びカリウムとも各々０，０５〜
α５　ｍｅ／Ｌのときに効果が大きい。本発明において
チタンとカリウムは両者を併用することによって効果が
得られ、チタン、カリウムがそれぞれα０５　ｍｏ　ｌ
／を以下では低温における触媒活性が不十分であシ、ま
た０、５ｍｏｔ／を以上でに増加させた割には効果は上
昇しない。The fjk of titanium and potassium to be supported prior to the above noble metals can be changed as appropriate depending on the purpose of use and the type of noble metal to be supported, but both titanium and potassium are each in the range of 0.05 to 0.05.
The effect is large when α5 me/L. In the present invention, the effect can be obtained by using both titanium and potassium in combination, and titanium and potassium each have α05 mol
If the amount is less than /, the catalytic activity at low temperature will be insufficient, and the effect will not increase even if it is increased from 0.5 mot/ or more.

チタン及びカリウムを触媒担体に担持させるにはＭ媒金
属を担持させる従来公知の方法と同様に炭酸塩、硝酸塩
等との水溶性チタン又はカリウム塩の水溶液を担持し、
含浸させ乾燥、焼成する方法によって行う。チタン及び
カリウムの４１１持しｊ通常別／くに行われ、いずれを
先に行ってもよいが、寸ｆｃ例えば蓚酸チタンカリウム
のように両者を含むＪ４　ｋ用いて同時に添加してもよ
い。含浸後の乾燥及び焼成温度は特に限定されないが次
の貴金属担持のためには２００℃以上で６時間位処理す
るのが好ましい。以下本発明の触媒について実施例及び
比較例を用いて説明する。In order to support titanium and potassium on a catalyst carrier, an aqueous solution of water-soluble titanium or potassium salt with carbonate, nitrate, etc. is supported in the same manner as the conventionally known method of supporting M-mediate metal,
This is done by impregnating, drying, and firing. The addition of titanium and potassium is usually carried out separately, and either one may be added first, but it is also possible to add both at the same time, for example, using a compound containing both, such as titanium potassium oxalate. The drying and firing temperature after impregnation is not particularly limited, but it is preferable to carry out the treatment at 200° C. or higher for about 6 hours in order to support the next precious metal. The catalyst of the present invention will be explained below using Examples and Comparative Examples.

実施（ｊｉｌｌ　１ 比表面積５０．ｉ／ｆ　　の球状アルミナ担体５００Ｃ
，Ｃに＋ｌＬ６モル／を炭酸カリウム水溶液全含浸し１
２０℃で２時間乾燥した後ろ００℃で６時間焼成した。Implementation (Jill 1 Spherical alumina carrier 500C with specific surface area 50.i/f
, C was completely impregnated with +lL6 mol/in a potassium carbonate aqueous solution 1
After drying at 20°C for 2 hours, it was fired at 00°C for 6 hours.

次に１８％塩化チタン水溶液全含浸し、１２０℃で２時
間乾燥後、４５０℃で焼成し更にもう一度含浸乾燥し８
００℃で３時間焼成した。、続いて０．５３モｎ−／１
硝酸セリウム水酵液を含浸し、１２０Ｃで２時間乾燥後
、６００℃で２時間焼成し／こ。次に０．２６　？／を
硝酸ロジウム水溶成金含浸し１２０“Ｃで２時間乾燥後
５００℃で３０分間焼成した。更に２．５７Ｖ／を塩化
白金酸六水和物の水浴液を含浸し１２０℃で２時間乾燥
後５００℃で３０分間焼成して触媒を得た。Next, the entire body was impregnated with a 18% aqueous titanium chloride solution, dried at 120°C for 2 hours, fired at 450°C, and impregnated and dried once more.
It was baked at 00°C for 3 hours. , followed by 0.53 mon-/1
Impregnated with cerium nitrate fermentation solution, dried at 120C for 2 hours, and then baked at 600℃ for 2 hours. Next 0.26? / was impregnated with rhodium nitrate water-soluble gold, dried at 120"C for 2 hours, and then fired at 500°C for 30 minutes. Further, 2.57V/ was impregnated with a water bath solution of chloroplatinic acid hexahydrate, and dried at 120°C for 2 hours. A catalyst was obtained by calcining at 500°C for 30 minutes.

比較例１ 比表面積５０ｎ？／ｌ　　の球状アルミナｌＩｊ体５０
０Ｃ，Ｃに実施例１と同様の操作でセリウム、ロジウム
、白金全４■持して（触媒を得た。但しこの触媒の場合
にはチタン、カリウムの何れ全も川持しなかった。Comparative Example 1 Specific surface area 50n? /l spherical alumina lIj body 50
Cerium, rhodium, and platinum were all deposited at 0C and C in the same manner as in Example 1 to obtain a catalyst. However, in the case of this catalyst, neither titanium nor potassium was retained at all.

実施例２ 酢酸で安定化したアルミナ含有率１０重量％のアルミナ
ゾル３００７に蒸溜水２５０７　ｉ加え更に硝酸アルミ
ニラ、！、　４４Ｍ’を加え攪拌して混合懸濁液分イ（
Ｉた。次に平均粒径１ａμのｒ−アルミナ６００ｆＩ全
混合懸濁液に加え、スラリーとした。Example 2 2507 i of distilled water was added to alumina sol 3007 stabilized with acetic acid and had an alumina content of 10% by weight, and further alumina nitrate was added! , 44M' was added and stirred to separate the mixed suspension (I).
I was. Next, it was added to a total mixed suspension of 600 fI of r-alumina having an average particle size of 1 amu to form a slurry.

このスラリー中に直径９３１１１１１１．長さ７６調の
ハニカムタイプの円筒状コージライト質モノリス担体用
基材を２分間浸漬し、引上げた後抗体基材セル内の余分
のスラＩＪ　　ｙ、空気流で吹き飛はし、１５０℃で３
時間乾燥した後、６ｏｏ℃で３時間焼成してモノリス触
媒用担体全得た。In this slurry, diameter 93111111. A honeycomb type cylindrical cordierite monolith carrier base material with a length of 76 scales was immersed for 2 minutes, and after being pulled up, the excess slurry in the antibody base material cell was blown away with an air flow, and then heated at 150°C. 3
After drying for an hour, the mixture was calcined at 60° C. for 3 hours to obtain the entire monolithic catalyst carrier.

次に、この゛担体Ｑ０．０５モル／を蓚酸チタンカリウ
ム水溶液に６０分間浸漬し、引き上げて液滴を空気流で
吹き飛ばした後１５０℃で６時間乾燥、Ｉ７！にもう一
度蓚酸チタンカリ水溶液に浸漬、乾燥し８００℃で１時
間焼成した。次に、この担体全１７モル／を硝酸セリウ
ム水溶液に１分間浸漬し、引き上けて液滴を空気流で吹
き飛ばした後１ｏ・ｏ℃で１時間乾燥、７００℃で２時
間焼成した。次にこのｔＬ１体を１　ｆ／を塩化白金酸
六水和物の水溶液に２時間浸漬し、引き上げてセル内の
液／１ｇ］’ｃ吹き飛ばした後、２００℃で３時間乾燥
し、次に０、０７　？／を塩化ロジウム水溶液中に６０
分間浸漬し、引き土ばてセル内の液を凶を吹き賎ばした
後２００℃で３時間乾燥して触媒をイｕた。Next, 0.05 mol of this carrier Q was immersed in an aqueous titanium potassium oxalate solution for 60 minutes, pulled out, and the droplets were blown off with an air stream, followed by drying at 150° C. for 6 hours, I7! Then, it was dipped once again in an aqueous solution of titanium oxalate, dried, and fired at 800°C for 1 hour. Next, a total of 17 mol of this carrier was immersed in an aqueous cerium nitrate solution for 1 minute, pulled up, and the droplets were blown off with an air stream, dried at 1 o.degree. C. for 1 hour, and calcined at 700.degree. C. for 2 hours. Next, this tL1 body was immersed in an aqueous solution of chloroplatinic acid hexahydrate for 2 hours, pulled out and the liquid in the cell was blown away, dried at 200°C for 3 hours, and then 0,07? /60 in rhodium chloride aqueous solution
The cell was immersed in soil for a minute, the liquid in the cell was blown out with soil, and the cell was dried at 200° C. for 3 hours to remove the catalyst.

比較例２ 実施例２と同じ操作で得られた直径９３窄長さ７６胡の
ハニカムタイプの円筒状モノリス触媒用担体に実施例２
と同じ操作でセリウム、白金、ロジウム金属持して触媒
を得た。但し本例の触Ｗでは実施例２とは異なり、蓚酸
チタンカリウムは担持しなかった。Comparative Example 2 Example 2 was applied to a honeycomb type cylindrical monolithic catalyst carrier with a diameter of 93 mm and a length of 76 mm obtained by the same operation as in Example 2.
A catalyst containing cerium, platinum, and rhodium metals was obtained using the same procedure as above. However, unlike Example 2, titanium potassium oxalate was not supported in the test W of this example.

上記の実施例、比較例で調製した触媒に４’ｌ持した金
属の量は第１表に示す１１［エリである。The amount of metal carried in the catalysts prepared in the above Examples and Comparative Examples was 11 [Eli] as shown in Table 1.

第　１　表 （江：金属相持量は触媒１を当りの３ｊｔ　ｋ示す。）
以上の様に調製した各触媒について空燃比ル乍をほぼ１
６にコントロールした排ガス中で５０時間の耐久試験を
行った。耐久試験時の触媒床湯度は約８００℃であシ、
空気速度（Ｓ、　Ｖ）は約６万Ｈｒ　　とした。Table 1 (E: The amount of metal supported is 3jtk per catalyst 1.)
For each catalyst prepared as above, the air-fuel ratio was approximately 1.
A durability test was conducted for 50 hours in exhaust gas controlled at a temperature of 6. The temperature of the catalyst bed during the durability test was approximately 800℃.
The air velocity (S, V) was approximately 60,000 Hr.

」二記耐久試験を行なった後の各触媒について触媒活性
能を測定した。The catalytic activity of each catalyst was measured after the durability test described in Section 2 was conducted.

活性能測定条件 モデルガス成分 ｃｏ：ｏ、ａｚ、ＮＯｘ　：　２．２　（ｌ　Ｏｐｐｍ
　、炭化水素（Ｃ３Ｈｓ　）　：　８”　ＩＦＱ２：０
．８４％Ｈ２：１１１７チ　Ｈｚ０：約６チ　Ｃ０２：
１０チＮ２：残部 上記組成よりなるモデルガスに０．８チの過剰０２．１
．６係の過剰ＣＯとなるように交互に１ヘルツ（Ｈｚ）
で導入した変動ガス全２００〜４５０℃に加熱し、Ｓｖ
約３万Ｈｒ　”’−’の割合で触媒に通じてＮ０ｘｋ還
元させ、ＣＯ及び炭化水素（Ｔ（Ｃ）を酸化させ、ＨＣ
，Ｇ。Activity measurement conditions Model gas components co: o, az, NOx: 2.2 (l Oppm
, Hydrocarbon (C3Hs): 8” IFQ2:0
．． 84%H2: 1117chi Hz0: Approximately 6chi C02:
10 chi N2: 0.8 chi excess 02.1 to the model gas with the balance above composition
．． 1 hertz (Hz) alternately so that there is an excess CO of 6 units.
The fluctuating gas introduced at
Approximately 30,000 Hr passes through the catalyst at a rate of ``-'' to reduce NOxk, oxidize CO and hydrocarbons (T(C), and oxidize HC
,G.

及びＮＯｘの浄化率全測定した。測定結果を第１図ない
し第６図に示す。第１図ないし第３図は実施例１と比較
例１の触媒を使用しての入口ガス温度と浄化率との関係
分水し、図中、央看イー赤寸Ａｌは実施例１の触媒の結
果を示しＢ１は比較例１の触媒の結果を示す。and NOx purification rate were measured. The measurement results are shown in Figures 1 to 6. Figures 1 to 3 show the relationship between inlet gas temperature and purification rate using the catalysts of Example 1 and Comparative Example 1. B1 shows the results of the catalyst of Comparative Example 1.

同様に第４図ないし第６図は実施例２と比較例２の各触
媒の結果を示し、Ａ２は実施例２の触媒の結果を示し、
Ｂ２は比較例２の触媒の結果を示す。図から朗らかなよ
うに本発明による触媒は特に低温域において高活性であ
り、高部域の排ガスに対しても耐久性が優れている。Similarly, FIGS. 4 to 6 show the results of each catalyst of Example 2 and Comparative Example 2, A2 shows the results of the catalyst of Example 2,
B2 shows the results of the catalyst of Comparative Example 2. As clearly seen from the figure, the catalyst according to the present invention is highly active, especially in the low temperature range, and has excellent durability against exhaust gas in the high temperature range.

実施例６ 比表面積５０ｒｒ？／／ｆＫＤ球状アルミナ相体１００
ＣＣに０２５モル／を蓚酸チタンカリウム水ｍ液を含浸
し、１２０℃で２時間乾燥した後、更にもう一度０２５
モル／を蓚酸チタンカリウム水浴液を含浸し、１２０℃
で２時間乾燥後８００℃で３時間焼成した。Example 6 Specific surface area 50rr? //fKD spherical alumina phase body 100
CC was impregnated with 025 mol/m of potassium titanium oxalate aqueous solution, dried at 120°C for 2 hours, and then impregnated with 025 mol/ml once again.
mol/impregnated with potassium titanium oxalate water bath solution, 120℃
After drying for 2 hours, it was fired at 800°C for 3 hours.

続いて［１５３モル／を硝酸セリウム水溶液を含浸し、
１２０℃で２時間乾燥後６００℃で２時曲焼成した。Subsequently, [153 mol/] was impregnated with an aqueous solution of cerium nitrate,
After drying at 120°C for 2 hours, it was baked at 600°C for 2 hours.

次に２．１ｆ／Ｌ塩化白金酸六水和物の水溶液を含１ｃ
４ｚ３モル／ｌ　、Ｃｅ１２モル／ｌ、Ｐｔ［Ｌ８ｆ／
ｌ　ｅ含有する。Next, 1c containing 2.1f/L aqueous solution of chloroplatinic acid hexahydrate
4z3 mol/l, Ce12 mol/l, Pt[L8f/
Contains le.

比較例３ 実施例３と同様にして比表面６ｓｏ靜／ｌの球状７　／
ｌ／　ミナ担体１ｏｏｃｃにＣｅ　０．２　モｉし／ｌ
　ｓ　Ｐ　ｔ　Ｏ−”　ｆ／を含有する触媒を調製した
。実施例３と異なる点’ｒｌ　侭ｆＩ！！チタンカリウ
ムを担持し斤いことである。Comparative Example 3 In the same manner as in Example 3, a spherical material with a specific surface of 6 so/l was prepared.
l/Mina carrier 10cc Ce 0.2 moi/l
A catalyst containing s P t O-" f/ was prepared. The difference from Example 3 was that potassium titanium was supported.

実施例４ 比表面８ｔ５０硝今　の球状アルミナ担体１００Ｃに＆
５条塩化チタン水溶液を含浸し１２０℃で２時間乾燥し
た後、５００℃で３時間焼成した。次に０．２６モル／
を炭酸カリウム水溶液を含浸し、１２０℃で２時間乾燥
後５００℃で３０分間焼成してＴｉＱ、Ｏｆモル／ｌ−
ｓ、　　ＫＬ）、ｚ３モル／ｌ−、Ｐｔ０．８ｆｌｔを
含有する触媒を得た。Example 4 A spherical alumina carrier 100C with a specific surface of 8t50
It was impregnated with a 5-line aqueous titanium chloride solution, dried at 120°C for 2 hours, and then fired at 500°C for 3 hours. Next, 0.26 mol/
was impregnated with potassium carbonate aqueous solution, dried at 120°C for 2 hours, and then calcined at 500°C for 30 minutes to obtain TiQ, Of mol/l-
s, KL), z3 mol/l-, and a catalyst containing Pt0.8flt was obtained.

比較例４ 実施例４と同様にして比表面積５０　ｍ”／９０球状ア
ルミナＪ［！体１００ＣＣＫ　ＰｔＯ，８？／を含有す
る触媒全調製した。チタン及びカリウムは担持しなかっ
た。Comparative Example 4 A catalyst containing 100 CCK PtO, 8?/ of specific surface area 50 m''/90 spherical alumina J [! body] was prepared in the same manner as in Example 4. Titanium and potassium were not supported.

実施例３、比較例３、実施例４、比較例４の触媒につい
て前述の耐久試験全行ない、印久彷の各触媒の大ガス温
度２５０℃、３００℃におけるＨＣ，ＣＯ浄浄化率側測
定た。第２表に１ｉｔＩ＋定結果を示す。The catalysts of Example 3, Comparative Example 3, Example 4, and Comparative Example 4 were all subjected to the aforementioned durability tests, and the HC and CO purification rates of each of Inkyu's catalysts were measured at large gas temperatures of 250°C and 300°C. . Table 2 shows the 1itI+ results.

以上の様に担持された貴金属が一神の場合でも父、セリ
クムのない場合でもチタン、カリウムの添加の効果は明
らかである。As described above, the effect of adding titanium and potassium is obvious whether the noble metal supported is one god or the father, Sericum, is not present.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図ないし第３図は実施例１及び比ＭＶｌ１１１の各
触媒の大ガス温度とＨＣ，ＣＯ並ひにＮＯｘ浄化率との
関係を示すグラフ。第４図ないし第６図は実施例２及び
比較例２の各触媒の大ガス温度とＩＩＣ、ＣＯ並びにＮ
Ｏｘ浄化率との関係を示すグラフである。 図中、 Ａ１・・・・・・実施例１の触媒 Ｂ、・・・・・・比較例１の触媒 入・・・・・・実施例２の触媒 Ｂ２・・・・・・比較例２の触媒 （ほか１名）1 to 3 are graphs showing the relationship between the large gas temperature and the HC, CO, and NOx purification rates of each catalyst of Example 1 and the ratio MVl111. Figures 4 to 6 show the large gas temperature, IIC, CO and N of each catalyst of Example 2 and Comparative Example 2.
It is a graph showing the relationship with the Ox purification rate. In the figure, A1...Catalyst B of Example 1,...Catalyst included of Comparative Example 1...Catalyst B2 of Example 2...Comparative Example 2 catalyst (1 other person)

Claims (1)

【特許請求の範囲】[Claims] 触媒担体にチタン及びカリウ７−ヲ相持して後、白金、
パラジウム、ロジウム等の触媒貴金属の一種又は二種以
上を担持せしめたことを特徴とする排気ガス浄化用触媒After titanium and potassium are supported on the catalyst carrier, platinum,
A catalyst for exhaust gas purification characterized by supporting one or more kinds of catalytic precious metals such as palladium and rhodium.