JPS61501134A - Contact exhaust gas purification device and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Contact exhaust gas purification device and its manufacturing method The present invention relates to a catalytic exhaust gas purification device and a method for manufacturing the same.

The background to the invention is that environmental authorities in many countries are putting pressure on industry to reduce pollutant emissions. It is to reduce the amount. Particularly in the case of the automobile industry, efforts are being made to reduce emissions from automobiles. This makes it necessary to take measures to To this end, the automotive industry Two approaches according to emission limits: one approach with engine modification; and by using so-called catalytic exhaust purification devices that produce chemical conversion of the exhaust gas. We are trying other approaches. The most successful solutions for catalytic exhaust purification devices are − A so-called fuel that can oxidize carbon oxides and unburned hydrocarbons and reduce nitrogen oxides. Contains Leeway catalyst. However, this type of catalyst requires stoichiometric air This solution has its best performance within the /fuel ratio range, so this solution is suitable for engine modifications. are also needed.

Catalysts for catalytic exhaust gas purification systems are generally used for catalysts that exhaust gas passes through on its way from the engine. The species applied to the filter must consist of a carrier substance fixed on the It consists of a catalytically active metal. Here, the honeycomb-like structure made of ceramic material is , often used as a support for filters or the catalyst itself. other The method involves coating the surfaces with catalytically active substances and then installing them in the exhaust pipe. including the use of a separate sphere or body sealed within a container of any kind. There is. Both honeycomb-shaped monolithic bodies and separate ceramic bodies are generally Coated with aluminum oxide, usually containing platinum, which acts as a mediating agent has been done.

An example of a known catalyst for catalytic exhaust gas purification is disclosed in Swedish (SX) Patent Application No. 7808 No. 434-0. This conventional contact exhaust gas purification device and Other prior art catalytic exhaust purification devices do not utilize the supplied catalytically active material in a sufficiently effective manner. This method has a number of drawbacks which mainly mean that it is not possible to use it in Umuru. This indicates that the surface coating applied to the carrier of the exhaust purification device has an optimal structure. and that the catalytically active material is only penetrated into the coating during feeding. within the body itself, where the catalytic material supplied will not come into contact with the exhaust gases. It is believed that this depends on the fact that it is also penetrated. Therefore, one object of the present invention is to These shortcomings can be overcome 1-1 and the supplied catalytic active material can be used more efficiently. The object of the present invention is to achieve an exhaust gas purification device that has the following characteristics. Another object of the present invention is to reduce exhaust gas and catalyst activity. The purpose of this invention is to ensure particularly efficient contact with the sexual substance.

Still another object of the present invention is to provide a method for manufacturing a catalytic exhaust gas purification device having such properties. It's about achieving.

Required in connection with the catalytic purification of exhaust gases from internal combustion engines of gasoline and diesel type. The key chemical reaction is carbon monoxide and hydrocarbons produced by incomplete combustion. , encompasses the combustion of hydrocarbons in the form of unburned vaporized fuels as well as hydrogen gas. The purification method is , such as nitrogen oxides, often collectively referred to as NOx, oxygen and and water vapor reduction should also be included.

Typical reactions that a catalytic exhaust purification system would like to promote are: Ru.

2(IO+Oz’ −→2C02・・・・・・・・・・・・・・・・・・・・・ ・・・・・・−・・・・・・・・・・・・1200 + 2NO-□ 2COI + N2・・・・−・・−・・・・・・・・−・・・・・・・・・・−・・・・2 So-called S The technology based on Leeway catalyst is K, e m i a kTtdskrift (Chemical Journal published in Sweden) No. 2/1984 It is listed. It is clear from this literature that catalysts are used for all types of harmful substances. It has a so-called recess or entrance window that allows for efficient purification of . However, The technique conventionally used to prepare Leeway catalysts is to This means that the so-called ignition temperature (at this temperature Emissions from the engine during the heating time until an exothermic reaction occurs are the main part of the total emissions. It necessarily involves developing a division. Another drawback inherent to known three-way catalysts is , these commercial catalysts can be used to filter out various components in fuels, such as lead, phosphorus, and sulfur. It is very sensitive to poisoning and thereby shortens the life of the catalyst containing such impurities. However, when using fuel that However, the combustion The composition of the alcohol will change and in the future alcohol, for example methanol or ethanol It can also be envisaged to incorporate alcohols, alcohols, and ketones into the fuel. In such a case, Increased emissions of aldehydes can occur when using current commercial catalysts.

Therefore, one object of the present invention is to provide a widened stoichiometric window with a λ value of less than 1.0. An object of the present invention is to provide a three-way catalyst having the following properties. In this way, the present invention Catalyst or catalytic exhaust purification device with lower ignition temperature (catalyst is lower than 300℃) have substantially lower activity and increase the ability to oxidize alcohol. The purpose is to manufacture (intended for). Still another object of the present invention is to obtained improved resistance to impurities such as carbon and sulfur, and also extended Guaranteed longevity and made it possible to use less precious metals than before. To provide a new method of applying catalytically active materials to new types of carriers for the purpose of It's there.

This and other objects of the invention have a carrier made of a heat resistant material and Catalytic exhaust purifiers having a coating containing a catalytically active substance on its surface in contact with the gas This is achieved by a conversion device. The coating has a surface area of at least 40 IO"/g s preferably at least 75 m”/g and an average pore size of at least 1 oo and at least 75% of the surface area is in pores with a diameter of more than 100 m do. The coating consists of aggregate particles and/or colloids having a cohesive three-dimensional network structure. Consists of id-like particles or their aggregates. Inside the contact exhaust gas purification device according to the present invention Catalytically active substances are concentrated in the coating. Currently, catalytically active material or before The precursor material is applied to the aggregate particles and/or colloidal particles and thus It is believed that the best use of the catalyst material is achieved if it is supported as such. Book In manufacturing the catalytic exhaust purification device according to the invention, the concentration of catalytically active substances in the coating is , first wetting the carrier and coating with an evaporative or volatile liquid and then removing the coating from the is allowed to evaporate but remains within the carrier, and then the coating is coated with the catalytically active material or its precursor. This is achieved by impregnation with a liquid containing the agent. Covered with catalytically active material Another possible method of concentration in the covering is to use the coating 7 to form on the body. The catalytically active substance or its precursor is added to the aggregate particles and/or colloids. This is a method in which it is deposited as a surface plate on particles of a certain size.

When the carrier is in the form of a monolithic body, for example of a nohenicum structure, the carrier is preferably contains zircon-mullite, mullite, α-muyu 208, sillimanite, silicic acid Magnesium, kaolin clay, zircon, betalite, spodumene, cordierite and mostly aluminum silicates. One of the suitable carriers Examples are obtained from Corning Glass Works in the United States, and from the Japanese company NGK. It is a cordierite carrier with a honeycomb structure.

On the other hand, if the carrier is made of spheres or other bodies, these bodies , porous silica, e.g. trademark Sirocel (S-LocxL)*Available products; granules Charcoal: α- or r-A1. in the form of granules or pellets. O,; natural or Bottom aluminum silicate; magnesium oxide, diatomaceous earth, bauxite, diacid titanium oxide, zirconium dioxide, limestone, magnesium silicate, silicon carbide, and activated or inactive carbon. These substances can be regular or irregular Particles in the form of particles, such as capillaries, extrudates, rods, spheres, shards or pebbles, etc. Kiro. These bodies are then coated with a suitable catalyst carrier and support for the catalyst material. It serves as a body. In known catalysts, this carrier for the catalytic material is often Often made of aluminum oxide or other heat-resistant materials, suitable as a gastrointestinal coat. It is used. Generally, the active substance is present in a total amount of about 1-2 g/l, e.g. gold, palladium and rhodium.

According to the invention, it should be applied to a carrier and should contain a catalytically active substance. The coating has a surface area of at least 40 m"/g, preferably at least 75 m"/g. m27g, and the average pore size should be at least 10X, as shown in the table. At least 75% of the area should reside within pores with a diameter greater than 100X. be. In order to obtain these properties, the covered object is made according to a preferred embodiment of the invention. Fibrous or strip-like structures and small diameter (both 100X and suitable machines) cohesive three-dimensional network structure of mineral particles containing physical stability, thermal stability and hydrothermal stability It consists of aggregate particles with a structure. nI bond-like or strip-like mineral particles are here Advantageously, attapulgite, haloisa used separately or mixed with each other It may consist of sepiolite, sepiolite and chrysotile. Giving the coating the above property 7 Another possible method is to use solid heat-resistant particles of colloidal size or such This is a method of making a coating from aggregates of

In this case, these heat-resistant particles can have at least a surface area. Particles are e.g. For example, it can be in the form of a liquid-supported sol or suspension and then deposited on the surface of the carrier. This gives a substantial increase in the activity of the resulting catalyst mass or body. , and the accessible surface area of the carrier material and the catalytically active material is The surface coating of obtain. Additionally, a heat-resistant agglomerate forming a coating and having a cohesive three-dimensional network structure Using such liquid-supported sols or suspensions to coat the surface of body particles A considerably improved accessible surface area of catalytically active material is then obtained.

In connection with the present invention, a cohesive three-dimensional network structure of g&fiber-like or strip-like particles is used. If it is desired to use a coating in the form of heat-resistant aggregate particles with As a step, industrial minerals in fibrous or strip-like structures in water, especially silica Made from extremely well-dispersed slurry of aluminum or magnesium silicate It is intended that In this context, "extremely well-dispersed slurry" means Mineral fibers or IJ tubes should be added to the slurry separately, and this This means that preferably no aggregate is formed. fibrous or S) Examples of aluminum silicate with IJ tube-like structure are attapulgite, sepiolite and halloysite, and fibrous or strip silica. An example of a magnesium acid is chrysotile.

Fibrous or strip mineral particles with high dry content (dispersed slurry) Dispersants such as water glass, aluminum, hydroxyl, etc. Use loride, polyphosphate, etc.

Within the scope of the invention, mixtures of different types of fibrous or strip-like mineral particles may be used. It is also contemplated to produce coatings formed from. Additionally, N! The male shape also is the formation of strip-like mineral particles with regular aluminum oxide or zeolite in the network structure. The present invention also provides coatings containing formulated particles of light, such as spray-dried particles. intended within the scope of the invention.

111, male-shaped or striped to obtain a three-dimensional network structure with desired properties. The mineral particles may be modified prior to formation of the three-dimensional network. Such degeneration is caused by Increasing the diameter of the fibers helps to increase the average pore size of the resulting network, or the catalyst It can serve to precipitate the active substance onto the surface of the mineral particles. But long In addition, the supply of catalytically active material is carried out until the desired network structure is produced and the mineral particles are placed on the carrier. It can also be done after it has been deposited.

The supply of catalytically active substances is impregnated with noble metals, e.g. platinum, palladium, etc. This can be done by

Slurry before spray drying into particles that can later be used to form onto coated carriers Dispersants should be used to safely achieve the required high degree of dispersion. place to become In some cases, it is desirable to avoid sodium-rich catalysts. At that time, aluminum Nitrium Hydroxychloride, Tetramethylammonium Silicate, Tetraethyl Hydroxide Tanol ammonium, ammonium citrate, ammonium tartrate, glycol Sodium-free dispersants such as ammonium phosphate and the like can be used. this All of them are made of aluminum silicate with fibrous or strip-like structure. Magnesium disilicate, such as attapulgite, seviolite, halloysite , is an excellent dispersant for chrysotile, etc.

Catalytically active substances, such as platinum, are used as carriers or catalysts in catalytic exhaust purification devices. When traditionally deposited on a carrier, the support or carrier usually contains e.g. platinum. It is impregnated with a salt solution. The salt is then reduced by using a suitable reducing agent. is reduced to its metallic form. This method often results in unnecessary waste of catalytically active material. Contains. In the present invention, this waste of material can be solved by either of two methods. This can be avoided by The first method is to first form a coating on a catalyst support and then Impregnating the body and its covering with a volatile liquid and then forming an object into the volatile liquid 7 evaporation of the catalyst carrier. Then this The thus dried coating is impregnated with a bath solution of, for example, a soluble noble metal salt in the conventional manner. , then the salt is reduced to its metallic form. After reduction, the catalyst is dried, thereby The volatile liquid is then removed from the carrier by evaporation. With this operating technique, i.e. First, the entire carrier is impregnated with the coating, then the coating is dried, and finally the coating is catalytically activated. The catalytically active substance is produced by impregnating it with a solution of the catalytic substance or its precursor. concentrated in the odor area of the contact exhaust purification device that actually comes into contact with the exhaust gas. It will be.

Another technique is to concentrate the catalytically active material in a coating on a support. A method of applying the precursor to particles or aggregates and subsequently forming a coating therefrom. It is the law. Compliance Both of these methods eliminate the problems encountered with current technology, namely the unnecessary wastage of material. It is possible to overcome the cost ``f''. Therefore, the present invention reduces the total amount of catalytically active material to Easy to keep small in terms of the extent of accessible catalytically active surfaces.

In highly preferred embodiments of the invention, therefore, colloidal sized refractory particles particles or aggregates of such particles. These particles contain catalytically active substances or or its precursor. Therefore, surface coating of catalytically active material It is possible to achieve a catalyst mass with a covering of solid sol particles with It is Noh. In this way, the catalytic material can be used while still having a highly effective catalyst. , so that only a small portion of the total catalyst mass of the catalytic exhaust purification device consists of catalytically active material. It will be concentrated within the surface of the loid-like particles.

A catalytically active substance t deposited on colloid-sized sol or suspension particles. A possible method is to first prepare at least x m"/g, preferably less than A liquid supported sol of carrier particles having at least 50 to 1000 m”/g or prepares a suspension and then dissolves the soluble metal compound in this sol or suspension; This compound is then applied to the surface of the carrier particles as a metal or a poorly soluble metal compound. This is a method of precipitation. In the practice of this aspect of the invention, very low concentrations One component (anion or cation) of a poorly soluble metal compound is a soluble compound. dissolve in a liquid-supported sol or colloidal suspension of rear particles; without exceeding the solubility limit of the compound in the liquid phase of the liquid phase of the suspension or suspension; Preferential adsorption of poorly soluble compounds onto particles without the formation of crystal nuclei of highly soluble metal compounds. It is possible to feed other components of the poorly soluble compound at a feed rate that allows for It is Noh. In this case, the coating technique must first be applied to the surface area accessible to the liquid, at least A liquid supported sol or suspension of carrier particles with im2/g is prepared and its After dissolving the soluble metal compound in this sol or suspension, it is then applied onto the carrier particles. based on the idea of precipitating metals or sparingly soluble metal compounds (. When a soluble compound is deposited onto colloidal particles, the components of the poorly soluble compound are then It is provided in such a way that precipitation occurs on the surface of the colloidal particles. This means that Before or after the reaction of one component with another without forming major aggregates of insoluble compounds colloidal compounds that are attracted by the particle surface or newly formed in association with Under strong stirring of the component 7 sol or @ suspension, so that it is preferentially attracted by the shaped particles. can be done by feeding simultaneously at different points or sequentially from each other. . In this context, "primary aggregates" here refers to so-called oligomeric or polymeric aggregates. Taste.

Addition of the components must be carried out under conditions that favor the stability of the colloid.

Thus, the electrolyte content in the solution increases the water turbulence that destabilizes and coagulates the colloidal particles. It should not exceed the critical content χ. This critical content is It depends on the size of the colloidal particles and the valence of the electrolyte. pH value also colloid is of great importance to the stability of the colloid, and therefore pH has a strong influence on the destabilization of the colloid. It should be kept at a value of zero. The same consideration should be taken regarding temperature. Ru.

However, coating colloidal particles with a coating of metal or a poorly soluble metal compound The reasons for the established effectiveness of this technique are not completely understood. that depends on adsorption or attraction, or the low concentration allows individual crystal nuclei to Such a short sol or suspension distance to the particle surface produces slow formation of crystal nuclei. depend on the fact that they are the same and are therefore attracted to the surfaces of the particles, but not to each other. I might.

The surface coating of gold on the sol or suspension particles is a reducible, poorly soluble metallization. It can also be achieved by precipitating it onto particles as a compound and then reducing it to the metal. Ru. Alternatively, the soluble compound of the desired metal may be should adsorb or attract molecules, and then these ions or molecules It can be dissolved in a sol or suspension for direct reduction to the genus.

According to embodiments of one aspect of the invention, soluble compounds (immediately i.e., a precursor of the desired final catalytically active substance) is dissolved in a sol or suspension. soluble Compounds in which virtually all metal ions or molecules in solution are subject to interfacial chemical forces, e.g. sol or suspension particles due to surface charges, van der Waals forces, dispersion forces, etc. is added in such an amount that it can be adsorbed or attracted by the surface of the surface. Then, the substance Very slow addition takes place. A substance has ions adsorbed or attracted by it. or the desired catalytically active substance or its precursor by reacting with the molecule. M is precipitated onto the surface of the suspension particles.

The production of coated sol or suspension particles can be carried out in several stages. That is, the particles are first Lacks suitable surface chemistry for the deposition of the final catalytic active substance or its precursor. If so, several layers can be made in the same way to change the surface charge of the initial sol or suspension particles from negative to positive. And it is possible to change it the other way around. Depositing a mixture of disintegrating active substances onto the particles The same technique can be used if desired.

According to one aspect of the invention, the sol or suspension particles thus have one or more catalytically active It will serve as a carrier for substances. In the liquid phase (aqueous phase) of a sol or suspension Separation of catalytically active substances at coating the surface of the sol or suspension particles without the appearance of precipitation (1) per unit volume of sol or suspension. The carrier particles (sol or suspension particles) are small so that the carrier surface is large. (2) the desired substance ( or its precursor), the resulting substance diffuses to the carrier surface, and within and without exceeding the solubility limit of the substance in the liquid phase of the sol or suspension. will have time to be deposited on the carrier surface without spontaneous formation of crystal nuclei. It is necessary for the process to occur slowly.

The simplest implementation of this aspect of the invention involves coating the surfaces of the sol or suspension particles. This method uses water as the liquid medium. However, it is intended If the substance is soluble in a liquid medium and can be precipitated from it with the techniques described herein, Other liquid media can be used.

The carrier in the form of a sol or suspension is the liquid phase used, usually preferably in water. have very low solubility in the liquid phase, or at least have very low dissolution rates in the liquid phase. must be maintained. Examples of such materials are polyvalent metal oxides, e.g. Minerals that exist in colloidal form, such as □, Mu1□03, ZrO2, re, O, etc. , such as oxides, silicates and aluminum silica. of such minerals Examples include kaolin, attapulgite, bentonite, volcanic ash, and dispersed asbestos. Ru.

In order for a sol or suspension to be usable in the present invention, the particles of the sol must be , the accessible surface should have a calculated large surface area. That's a big deal Particles with a hard and spongy structure have a large inner surface; This is because the solution in which the coating is precipitated or deposited is not necessarily accessible.

The required size of the accessible surface is determined by a number of different factors and their Among these, the interfacial chemical effect on the surface is one of the most important. Surface accessible to solution should be at least 1 m”/g to allow practical production rates.50 A surface area larger than m"/g is preferable, and the practical range is 50 to 1000 m" /g.

For silicic acid sols as carriers for deposited catalytically active substances, particle sizes of approximately 4 to 9 Sols with a surface area of 300-700 m”/g corresponding to nm are advantageously used. It can be done.

As mentioned above, the particles of the initial sol or suspension precipitate the desired final catalytically active material. It is not necessary to have a polar surface charge necessary for adhesion. In this way, The icic acid sol (with negative surface charge) contains the desired catalytically active substance or its precursor. If necessary for deposition or precipitation, first e.g. from basic aluminum chloride. It can be modified with a polyaluminum compound to have a surface charge. Slightly In the case of , the polarity can also be influenced by the pHΔ of the liquid medium. For example, For icic acid sol, the surface of the sol is approximately neutral at pH 2-3 and has a negative charge. The load increases with increasing pH. Depending on the system, this changes the pH to the surface charge. It is possible to use it as a preparation. Another way to increase the negative charge of silicic acid particles The step involves reacting aluminum with the surface of the silicic acid particles to form negative 5IA14'' points. Is Rukoto. Such modified silicic acid, in contrast to unmodified silicic acid sol, has an acidic pH. It also contains a considerable amount of negative charge. Adsorption or attraction may be due to surface charge or may be obtained by other mechanisms, however, the carrier particles has the ability to adsorb or attract one or more of the components of (e.g. to ensure that the surface of the carrier particles has a suitable surface charge) By ensuring the precipitation of sol particles onto the surface by slow (and controlled precipitation rate) It is necessary to be able to direct the

Another requirement for the carrier, i.e. sol or suspension particles, is the deposition or precipitation conditions. It should have a low dissolution rate or be insoluble under certain conditions. The reason is that it would be difficult to deposit or precipitate other substances onto the surface of the particles. It is.

Deposition conditions are such that sol or suspension particles (or modified particles) of the carrier material are in solution. substances which are present in the substance and which are subsequently to be included in the precipitated or deposited substance. A complete table large enough for interfacial chemisorption or attraction of virtually any ion or molecule The conditions must be such that it has a surface. It is then absorbed into the sol or suspension particles. one or more other ions or molecules to combine with the attached or attracted ions or molecules; The chemical compound or compounds to be precipitated or deposited diffuse to the surface of the particle and then deposited on it without exceeding the solubility limit and without spontaneous formation of crystal nuclei in solution. It must be fed at such a slow rate that it will have time to run.

Coating onto colloidal carrier particles without formation of new free crystal nuclei in solution The rate at which it can be made depends on the crystallinity of the coating, and what materials over a very wide range depending on how they are combined to form a coating. Change.

The surface of the colloidal particles should contain a catalytically active metal, such as Pt or pa. When desired, these catalytically active surfaces reduce metal compounds together with colloids. It can be produced by depositing metal particles directly onto the surface of colloidal particles. child An alternative method for successively collecting the metal is to first precipitate the insoluble compound of the metal onto the surface of the particles; The process then converts this compound into a catalytically active form of the metal.

Liquid-supported sols or suspensions of surface-coated sols or suspension particles are prepared by spray drying. can be used to prepare catalytic materials. To prepare the catalyst, the surface of the catalyst support is It is advantageous for the back skin to coat the surface with said surface-coated solid sol or suspension particles. Ru. This means that the accessible surface area of the catalytically active material is 2 compared to when deposited directly on the surface of the catalyst support instead of on the surface of the sol particles. It would be increased by ~3 times, thus giving an advantageous increase in the activity of the resulting catalyst.

Another possible way of applying the catalytically active substances to the coating of the support is to apply one or more catalytically active substances to the coating of the support. Particles of very small quality are prepared using the microequivalent method described in IP-Bl No. 0055257. This is a method of depositing according to the Margeskin technique. According to this technology, the intended Small particles of reactive catalytic materials, such as cobalt sulfide and molybdenum sulfide, are suspended/ A microemulsion is first prepared.

This microemulsion can then be made into a slurry of fibrous or strip mineral material. mixed with lee. These fibrous or strip-like mineral particles are made of cobalt sulfide. coated with a layer of small particles of molybdenum and molybdenum sulfide. Similarly, Kinmen Shirokane's small It is possible to first prepare a microemulsion in which the particles are suspended.

Application of the coating to the catalyst support is preferably carried out so that the support absorbs liquid from the suspension. A wash in which a liquid-supported suspension of waxy particles is delivered to a porous dry carrier. It can be carried out according to the coating method or the slip casting method.

The particles of the suspension are then deposited on the outside of the carrier or if the carrier has a honeycomb structure. adheres simultaneously to the surface of the carrier, no matter where it is located within the channel of the carrier. Will. This coating technique is conventional. The particles of the suspension are already catalytically active. If equipped with its own surface coating, the catalytic exhaust purifier will After applying this pressure end. On the other hand, the coating is first formed and has a surface area of at least 40 m”/g s preferably at least 75 m”7 g, and average pore size not less than both have a diameter of 100 A and at least 75% of the surface has a diameter greater than 100 μm If present in the pores, the addition of the catalytically active substance covers the entire support and the coating thereon. first impregnated with evaporative liquid and then evaporated liquid? Partially removed from the coating by evaporation before impregnating the coating with a solution of the catalytically active substance or its precursor. shall be carried out in accordance with the techniques described.

The invention will be explained in detail with reference to different examples. However, these examples It should not be construed as limiting the scope of the offer.

In some of these examples, trade names obtained from Engelhardt Minerals Attapulgite of ATTAGE/1-(ATTAGKL) was used. This atapa Lugite contains 5i0268%, A1□0,12% and Mg010-51. have

In the example, soda water glass or sodium silicate solution from Nika Chemi AB liquid was used. In this case, the ratio of 810□ to Nano is 3.3:1. , 81oz content was 26.6%, and density was 1350kg/m3. Ta.

The aluminum hydroxide used has the formula: 12(OH), CI.3R20. Cyclolide is available from Hoechst under the trade name ``KLORHYDROL''. ) Obtained by ACHJ.

Example 1 Water 101 containing "chlorhydrolum C11" (dried attapuljai) Add attapulgite in an amount equivalent to 1.81 kg. “Cracks” in slurry Lorcht.

The content of Rollum OHJ is calculated from 100g of dry Athanokurugite and is A120. This corresponds to 315 g. Add Athanokurjaiton while stirring vigorously.ノ＼nikam Dried cans of construction are immersed in the slurry, and the excess is expelled with compressed air.

The monolith thus obtained was placed in a heating cabinet at 110°C for 2 hours. After drying for a while, it is baked at 750°C for 4 hours.

After this treatment, the monolith and the attapulgite coating fixed on it are impregnation by immersion in a ton of water, then expel excess acetone with compressed air. Partial drying 7 of the coating rather than the carrier is obtained.

The thus partially dried monolith was then washed with 200 ml of deionized water. Immerse in a solution of 30.488 g of RhCl and 41.658 g of PtCl in Ru. Spit out excess solution and remove the still wet monolith with J8 gas. Put it in the flow. After that, drying was carried out at 125℃ for 7 hours, and baking was performed at 550℃ for 2 hours. Do it for a while. The resulting monolith can be placed in a suitable cage, e.g. of stainless steel sheet. After being sealed, it can be used as a catalytic exhaust purification device.

Example 2 Well-dispersed slurry of attapulgite in water and water glass as dispersant - Prepare. The fiber surface of the slurry particles is coated with 2ooX thick aluminum silicate. layer) and reslurry, then spray drying. three-dimensional mesh structure Aluminum silicate-coated attapulgite 11jl: Fiber carrier particles ,can get. These carrier particles were then treated with the catalytically active material in the manner described in Example 1. coat with texture. After reslurrying in water, these carrier particles are added to the honeycomb Used to form wash cordons on structural supports.

Contains 81024°85% and has a surface area of 3921 g (corresponding to a particle size of 7 nm) and has a pH of 9.7, and 25% of the atoms in the surface are aluminum atoms. Silicic acid sol 501iC whose surface is modified with thorium aluminate 160 g of an aqueous solution containing 1Co (!14-6H280,256 g and Na2 160 g of an aqueous solution containing 200.272 g of S-9E was simultaneously added dropwise with strong stirring. do. The cofeeding rate corresponds to 10 gK of solution every 27 minutes. Maintain the solution at a temperature of 25°C. hold The sol solution gradually turns black as the solution is added, but CO No precipitation occurs. If this sol solution is ultracentrifuged, black sol particles will settle and a clear supernatant will be obtained. And then, sediment. will contain sulfide and Co8 corresponding to the cobalt supply. Contact In the production of catalytic exhaust purification devices, a sol solution is used to deposit a layer of catalytically active particles on the surface of a catalyst support. Even though it deposits on the surface! can be used directly. Alternatively, the sol solution has a three-dimensional network structure. In a catalytic exhaust purification device, the catalytic exhaust gas purifier is can be used to deposit catalytically active materials in

Example 4 Nickel sulfide N1C U2.6H200,256 on aluminum modified silicate sol Example 1, except that an aqueous solution containing 160 gt of sodium sulfide solution is added. Repeat step 3. The sol solution gradually turns black when two types of solutions are added. However, no precipitation of nickel sulfide occurs. If this sol solution is ultracentrifuged, If so, the black sol particles will settle and a clear supernatant will be obtained. sedimentation The material contains Hls corresponding to the supply of sulfide and nickel. However However, the sol solution is prepared by applying a coating of catalytically active sol particles onto a monolith of the type described in Example 1. A three-dimensional network structure where catalytically active particles are deposited or present on such a monolith It may be used either for deposition within a coating.

The catalyst thus obtained can be used for a catalytic exhaust gas purification device.

5in2 contains 11.5% and has a surface area of 476 m”/g (for a particle size of 7 nm). reaction) and pH 10, and 25% of the atoms in the surface are aluminum atoms. 100g of silicic acid sol whose surface has been modified with sodium aluminate so that 45 g of 0.2M Na, 5-9E, 0 solution was added dropwise to the solution under strong stirring. after that, Lower the pH to 4.3-4.4 by addition of 5M HCl solution under vigorous stirring. So After PHy! 5% molybdic acid a Add 12.8g of ammonium (NH4) @M O7024・4H20 solution to sol solution Add under vigorous stirring. Perform experiments at room temperature. The sol solution is ammonium molybdate When adding the molybdenum sulfide solution, the color gradually turns black and gray, but no precipitation of molybdenum sulfide occurs. stomach. If the obtained sol solution is subjected to ultracentrifugation, a black-gray precipitate will settle out and The molybdenum and sulfides supplied therein can be found quantitatively.

If this experiment were repeated without the presence of aluminum-modified silicate sol, A black-gray precipitate of budene will be obtained in the reaction vessel.

After that, the aluminum-modified silicate sol of particles with molybdenum sulfide inclusions was Sol particles with a molybdenum sulfide coating are incorporated into the coating to act as a catalyst material. Advantageously, the coating is used to impregnate the catalyst support. Obtained catalyst can be used to purify automobile exhaust gas.

A solution of 200.2 g of "(NOs)z.6H in 100 ml of water was added from Condea. Aluminum oxide sol ``View.The surface of the sol particle has 25 circles of atoms within the surface. It is modified with sodium aluminate to make it an aluminum atom. Sol is , has a surface area of 110 m''/g.

The solution prepared in this way was added with (NHa)sMOyO□ in 100 ml of water. Slowly drop a solution of 4.Hzoo-2g into the solution while stirring. Adjust to 10.5 with ammonium hydroxide. Leave the solution stirring for 1 hour. temperature is 25°C. During centrifugation, aluminum oxide or a slightly pink precipitate A clear and colorless supernatant liquid was obtained. The supply of cobalt and molybdenum is Found quantitatively on aluminum oxide particles. Experiment with aluminum oxide in sol If the pH is adjusted to 10.5 with ammonium hydroxide, the blue A brownish precipitate should be obtained.

The aluminum oxide was then coated with molybdenum oxide and cobalt oxide. It is used to produce washcoats on /S bicam structure catalyst supports. profit The resulting catalyst can be used as a catalytic exhaust purification device.

Contains 2 ml of hydrazine hydrate at 810.3.94%' and has a surface area lo om"/gyIl- to the silicic acid sol having the Prepare the solution.

HO such that it contains 30 g/l of Pt and is 5.8 M with respect to HOl 4.5 ml of H2PtO Yu6 solution acidified with I and 20.5 ml of water. Dilute. The second bath liquid Y thus obtained was fed at a rate of 0.37 ml to the first solution. /min while stirring. Upon addition of the second solution to the first solution, the pH never reached 4. Ammonium hydroxide solution is also added dropwise so as not to fall below 3. The obtained solution Heat slowly to 50°C. During reduction to metallic platinum, the solution is colored black. , no separated precipitation of platinum occurs. If the reduction is carried out in the absence of silicate sol, black A colored precipitate forms. After completion of reduction in the presence of sol, the sample is centrifuged.

A black precipitate and a clear colorless supernatant are then obtained. The supply of platinum is , commonly found in sediments. Platinum-coated silicic acid sol particles act as a catalyst It is applied to folded bodies, has a three-dimensional network structure, and has a fibrous or attapulgite structure. or in the form of a sol to coat the surface of a coating consisting of strip-like particles. Ru. The catalyst obtained in this way can be used for catalytic purification of automobile exhaust gas. It is Noh.

The first solution has a surface atomized such that 25% of the atoms are aluminum atoms instead. Silicic acid sol modified with sodium luminate [This silicic acid sol is 8101z 3.87% and has a surface area of 110 m”/g (corresponding to a particle size of approximately 22 nm). Example 7 except that the solution of hydrazine hydrate 2Ilo1 in 25 g of repeat. If this sol is then centrifuged, a dark brown precipitate and a transparent A bright, colorless supernatant liquid is obtained, and the platinum supply is found quantitatively in the sediment. death However, the sol is composed of attapulgite fibers and has a three-dimensional network structure. and used to impregnate coatings applied to catalyst supports as washcoats. used. The product obtained in this way can be used as a contact exhaust gas purification device. be.

Example 9 In order to achieve maximum savings of precious metals in the ceramic body of the catalytic exhaust purification device, it may be produced by the method described below. Compared to commercial catalysts, noble metals, preferably P The amounts of t and Rh are quite small and the coating is impregnated only by the quache coat. and substantially the catalytically active material is also present in a carrier support of e.g. cordierite. It's done in a way that it wouldn't be. Impregnation yields a concentration gradient of catalytically active substances The highest concentration of is at the surface and a very small content is near the surface of the cordierite carrier. It is done as it is.

The production of contact exhaust gas purification equipment is carried out using the following steps.

1) For example, Al1Ox '65%, CeO223%, solution (for example, 330 g /l) 15.0 ml are mixed with 85 ml of deionized water.

2) Mix 50 g of l-mu 1203 powder into the obtained solution for 10 minutes with constant stirring. Ru.

3) Evaporate the material to dryness under stirring and dry in an oven at 120° C. for 16 hours. Ru.

4) Crush the material into powder.

5) Calcinate the powder at 550°C for 2 hours.

6) Add to the deionized powder from step 5 just enough Ni (!1 Impregnate with 210°og aqueous solution.

7) Dry at 125°C and bake at 650°C for 2 hours.

8) Add deionized water to a dry content of 46% or 68CP.

9) Mill the material in a ball mill for 19 hours.

xo) Example t shows a number of samples of Corning cordierite as described above. Immerse in the prepared particle suspension or washcoat suspension. Compress excess air Exhale and bake the sample at 500° C. for 2 hours.

An example of gradient coating of precious metals is performed in the following manner.

11) Rh+, 13 0-488 g and PtCl41.658 g were deionized. Dissolve in 200 ml of water.

12) Soak the sample from step 10 above in acetone, pour out the excess, and Then, the sample is immersed in the cooling bath solution from step 11 above. Spit out excess and depend on it. Sample Y, which is naturally wet, is placed in the gas flow.

13) Dry the sample from step 12 above at 125°C and 2 hours at 550°C. Fire.

14) Another sample of the same cordierite material was soaked in methanol and then Processes 12 and 13 are performed.

15) Still another sample was immersed in 2% H3PO4, and then subjected to the steps 812 and 812 above. 13 processes are performed.

16) Another sample was immersed in water saturated with H,8 and the excess was poured out. The sample is then soaked in the noble metal solution from step 11 above.

17) Dry the sample from step 16 above at 125°C and 550°C for 2 hours. Fire.

Figure 1 shows, on an enlarged scale, the honeycomb structure carrier and the slip cast on its inner surface. Figure 3 illustrates cefsilane in the included washcoat layer (11).

Figure 2 shows the honeycomb structure carrier being wash coated according to the steps 1 to 1O above. After coating and drying the support thus obtained, the precious metal from step 11 above Ordinary car exhaust cleaner produced by soaking in metal solution and then re-drying Block) Y diagram regarding the pt signal that establishes the pt distribution within the catalyst.

As can be seen from the figure, the platinum content in the carrier is higher than that in the washcoat. To a lesser extent, platinum is present in both the carrier and the washcoat.

FIG. 3 shows a similar product for an automobile exhaust purification catalyst manufactured according to step 13 above. Illustrate the cut. Support and plastic or polymeric materials (before the catalyst is cut into the sample) It can be seen from this figure that the two (embedded in) have the same signal strength. . This means that the carrier in this case does not substantially absorb platinum, while the platinum content is This indicates that it was high within the court.

FIG. 4 shows the wash inside the automobile exhaust purification catalyst manufactured according to step 15 above. Figure 2 is a more detailed plot showing the platinum distribution in the coat. Platinum is a washco The platinum concentration was free from the washcoat from the carrier. It can be seen from this figure that it increases towards the surface.

As can be seen from Figures 2 to 4, the maximum concentration of the catalytically active substance is determined in this way. will be obtained within the washcoat and a very small content of this substance Or nothing at all can be obtained in a coke-light carrier. Figure 2 - No. The analysis according to Figure 4 was carried out using a scanning electron microscope, namely an electron probe micro Anara (f-JH; 0L-357WD8-1? 6゜ made according to this example) The catalyst according to the present invention can be used as a catalytic exhaust purification device for purifying automobile exhaust gas. It has been found to be excellent. Manufactured according to steps 13, 15 and 17 above The catalytic activity of the prepared catalyst was established by testing and was found to be: Found waste space velocity (GH8V) 50000h-” 50000Qh-’A, acid Chemical (X) 10, Co + Ox ignition temperature 250℃ 240℃ Conversion ratio: 400’C: 100min 375°C: 8596470°C: 85 excellent 550℃: 88% B, reduction temperature Co-)-NQ00-)-N.

Ignition temperature 340'C340℃ Conversion ratio 43π:93-94ch 480℃=95% 480℃284% 2. Catalyst gas space velocity 1i (GE18V ) 50000h 500000h-''IA, oxidation CO+0□00+0 □ Ignition temperature 280℃ 240-250℃ Conversion ratio 280℃: 10 375 ℃：67%470℃268% 580℃=69% B, Reduced Co -) - No Co +170 Ignition temperature 360℃ 340℃ Conversion ratio 435℃: 92% 480℃=704630℃=70% 3. Catalytic gas space velocity CGREV treated with hydrogen sulfide according to step 17 above 50000 h-' 500000 h-" A, oxidation co + o, co - 4-o.

Ignition temperature: 300'C240'C Conversion ratio 300℃: 10()1 370℃ near 4% 440℃=80% 580℃=85% B, reduction Co-)-No CO1N.

Ignition temperature: 360'C340'C Conversion ratio 435℃: 93-94% 480℃ near 8% 550℃: 93-9 44 630°C near 8% Catalyst prepared according to steps 13.15 and 17 above analysis shows that the precious metal content is approximately 7g/l (calculated on solid content) and the density is 7 showed that it was about 0-74 g/am''.

18 people 1986-501134 (11) International search report kll+'#IIa"alA6i1ftlo*M, PCTjS-28', +/n nn1A""""""An"""No PC/5E85100038+-direction m ao+l+u+mwe,PCT,/S[85100038

Claims (13)

[Claims] 1. consisting of either a separate refractory body or a monolithic refractory porous body, and A heat-resistant support having a coating containing a catalytically active substance on its surface in contact with gas. A catalytic exhaust purification device consisting of a body, the covering having a surface area of at least 40 m2/ g, preferably at least 75 m2/g, and an average pore size of at least 100 Å. (at least 75% of the surface area is within pores with a diameter greater than 100 Å) ), and has a cohesive three-dimensional network structure of fibrous or strip-like particles consisting of heat-resistant aggregate particles and/or solid heat-resistant particles of colloidal size or or aggregates thereof, and the catalytically active substance is concentrated in said coating. A contact exhaust gas purification device characterized by: 2. The catalytically active substance is represented on aggregate particles and/or colloidal sized particles. 2. Device according to claim 1, characterized in that it is deposited as a surface coating. 3. Aggregate particles with a cohesive three-dimensional network structure consisting of fibers of Chrysotile, Seviolite or Chrysotile or mixtures thereof. The device according to claim 1 or 2, characterized in that: 4. The solid particles of colloidal size are aluminum oxide and/or silica. 3. The device according to claim 1 or 2, characterized in that: 5. The surface coating on the particles comprises at least one noble metal, such as metal ruthenium, Metallic platinum or metallic palladium, or metallic potassium, nickel oxide, sulfide molybdenum Livedenum + cobalt sulfide, molybdenum sulfide + nickel sulfide, tungsten sulfide + Cobalt sulfide, tungsten sulfide + nickel sulfide or rare earth metal oxides, or or a mixture of such substances. The device according to any one of the items. 6. The coating is composed of aggregate particles having a cohesive three-dimensional network structure, and the aggregate particles are particles of clay and/or zeolite material trapped within a three-dimensional network structure. The device according to any one of claims 1 to 5, characterized in that it contains: 7. The heat-resistant carrier is either from a separate heat-resistant book or a monolith heat-resistant porous body. a coating on its surface which is formed and in contact with the exhaust gas, said coating being in contact with the exhaust gas; The catalytic exhaust gas purification according to any one of claims 1 to 6, which contains a catalytic active substance. In manufacturing the device, the coating has a surface area of at least 40 m2/g, preferably at least 75 m2/g and an average pore size of at least 100 Å, the surface at least 75% of the volume is obtained within pores of diameter greater than 100 Å, and the coating is a heat-resistant agglomerate with a cohesive three-dimensional network structure of fibrous or strip-like particles. formed from carrier particles consisting of body particles and/or of colloidal size. formed from solid heat-resistant particles or agglomerates thereof, and the catalytically active material is A method for manufacturing a catalytic exhaust purification device, characterized in that the catalytic exhaust gas purification device is concentrated in a coating. 8. Applying a catalytically active material to the carrier particles before forming a coating therefrom. The method according to claim 7, characterized in that: 9. Soluble metal compounds in a liquid supported sol or suspension containing carrier particles soluble (the carrier particles have a liquid accessible surface area of at least 1 m2/g, preferably or 50, 1000 m2/g) and then the surface of the carrier particles. catalytically active substances by precipitating them as metals or sparingly soluble metal compounds on surfaces. Claims characterized in that the substance or its precursor is applied to carrier particles The method described in Section 7 or Section 8 o 10. The soluble metal compound dissolved in the sol or suspension is Consisting of one component (anion or cation) and dissolving the dissolved component at the interface under normal conditions. sol or in insufficient amounts with respect to the ability of the carrier particles to chemisorb or attract Supplementary components of the sparingly soluble metal compound are fed into the suspension and do not precipitate during feeding. The poorly soluble metal compound diffuses to the surface of the carrier particles and forms a sol or suspension. The solubility limit of the sparingly soluble metal compound in the liquid phase of the compound is not exceeded and the sparingly soluble metal is The compound will have time to be deposited on it without the spontaneous formation of crystal nuclei. the metal surface coating is applied to the surface of the carrier particles. To obtain the above, the metal is first precipitated as a reducible, sparingly soluble metal compound, and Therefore, after pre-drying of the sol or suspension particles, the reducible, poorly soluble metal compound is reduced to metal. 10. The method of claim 9, wherein: 11. Emulsifying an aqueous solution of the catalytically active substance or its precursor in a water-immiscible liquid; microemulsions are prepared by converting them into a solid state therein, and these are transferred to a carrier. Catalytically active substances or their precursors from microemulsions before coating on surfaces Microemulsion technology, in which substances are deposited onto carrier particles, - Claim 7 or 8, characterized in that the particles are coated with a catalytically active substance. The method described in section. 12. The catalytically active material or its precursor is deposited on heat-resistant solid colloidal particles. , and these particles are then formed into a cohesive three-dimensional network before applying the coating to the carrier. Claim 7, characterized in that it is submerged on heat-resistant aggregate particles having a structure. The method according to any one of Item 11. 13. First, the carrier and the coating are wetted with the evaporative liquid, and then coated with the evaporative liquid. The catalytically active material or its The catalytically active material is deposited onto the coating by impregnation with a liquid containing a precursor of 9. A method according to claim 7 or 8, characterized in that the method comprises depositing.