DE102006034119A1 - Filter for the removal of particles from a gas stream and process for its preparation - Google Patents

Abstract

The invention relates to a filter for removing particles from a gas stream, in particular soot particles from an exhaust gas stream of an internal combustion engine, comprising a filter body made of a ceramic filter substrate, wherein the filter substrate is coated with a porous cover layer and the porous cover layer contains at least one of the following substances: (a) at least one alumina selected from alpha-, gamma-, delta- and theta-alumina, (b) alumina hydrate doped with silica, at least one oxide of a metal of 3rd to 5th subgroups, at least one oxide of one Lanthanides including the lanthanum or a mixture of one or more of these oxides, (c) aluminosilicate, magnesium aluminum silicate or aluminum titanate, (d) silicon dioxide or silicon-rich zeolite, (e) titanium dioxide containing at least one oxide of a metal of the 3 rd bis 6th subgroup or an oxide of a lanthanum including the lanthanum (f) a mixture of zirconium dioxide with at least one oxide of a metal of the 3rd to 5th subgroups, at least one oxide of a lanthanide including the lanthanum or a mixture of one or more of these oxides or (g) a cerium oxide containing at least an oxide of a metal of the 3rd to 6th subgroup or an oxide of a lanthanoid including the lanthanum is doped. The porous cover layer additionally contains at least one catalytic ...

Description

State of the art

The The invention is based on a filter for the removal of particles from a gas stream, in particular from soot particles from an exhaust stream of a Internal combustion engine according to the preamble of claim 1.

such For example, filters become more self-igniting during exhaust aftertreatment Internal combustion engines, in particular in diesel-powered motor vehicles, used. Usually such filters for the removal of particles, so-called particle filters, from the ceramic materials silicon carbonate, aluminum titanate and / or cordierite. The particulate filters are generally in the form of a honeycomb Ceramic formed with mutually closed channels. such Particulate filters have a filtration efficiency of more than 80% to regularly larger than 90%. The difficulty, however, is not only in the filtration the soot particles but also in the regeneration of the filter. This will be fuel or its decomposition products in an exhaust aftertreatment arrangement, comprising the particulate filter, catalytically oxidized to the ignition of soot to produce necessary temperatures. During the hotter regeneration phases become highest Requirements placed on the thermal stability of the filter.

Thermochemical Reactions of the filter material with exhaust gas components and during operation over the Life of the motor vehicle on the filter accumulating ashes, for example from oil, Fuel, fuel additives or engine wear, reduce the mechanical and thermochemical strength of ceramic filters. By thermochemical reaction aged filter, especially if this made from the materials cordierite and aluminum titanate, have a higher one Failure probability on as non-aged filter. With high Thermal stress increases the probability of failure.

Usually Particle filters are currently used, their ceramic filter substrate is uncoated or only with a catalytically active coating is provided. The catalytically active coating causes harmful gases saved and implemented. This reaction heat is released. These heat of reaction contributes to Achievement of the exhaust gas temperature necessary for the regeneration of the filter at. In general, depends the degree of regeneration, i. its completeness, among others of the regeneration temperature and the heat distribution within the Particle filter off. One possible full Regeneration is required because remaining soot increases the exhaust back pressure and through the accumulation over the operating time and subsequent ignition to destroy the Particulate filter lead can. An exclusively However catalytically active coating has the disadvantage that through this the thermal or hydrothermal stability of the particulate filter is not elevated becomes.

Disclosure of the invention

Advantages of the invention

• a) mindestens ein Aluminiumoxid, ausgewählt aus alpha-, gamma-, delta- und theta-Aluminiumoxid,
• b) Aluminiumoxidhydrat, welches dotiert ist mit Siliziumdioxid, mindestens einem Oxid eines Metalls der dritten bis fünften Nebengruppe, mindestens einem Oxid eines Lanthanoiden einschließlich des Lanthan oder einer Mischung eines oder mehrerer dieser Oxide,
• c) Alumosilikat, Magnesium-Aluminium-Silikat oder Aluminiumtitanat,
• d) Siliziumdioxid, Siliziumcarbid oder Silizium-reiches Zeolith,
• e) Titandioxid, welches mit mindestens einem Oxid eines Metalls der dritten bis sechsten Nebengruppe oder einem Oxid eines Lanthanoiden einschließlich des Lanthan dotiert ist,
• f) eine Mischung aus Zirkondioxid mit mindestens einem Oxid eines Metalls der dritten bis fünften Nebengruppe, mindestens einem Oxid eines Lanthanoiden einschließlich des Lanthan oder einer Mischung eines oder mehrerer dieser Oxide oder
• g) ein gegebenenfalls dotiertes Ceroxid.

An inventively designed filter for removing particles from a gas stream, in particular soot particles from an exhaust gas stream of an internal combustion engine, comprises a filter body of a ceramic filter substrate, wherein the filter substrate is coated with a porous cover layer and the porous cover layer contains at least one of the following substances:

• a) at least one alumina selected from alpha, gamma, delta and theta alumina,
• b) alumina hydrate doped with silica, at least one oxide of a metal of the third to fifth subgroups, at least one oxide of a lanthanoid including the lanthanum or a mixture of one or more of these oxides,
• c) aluminosilicate, magnesium aluminum silicate or aluminum titanate,
• d) silicon dioxide, silicon carbide or silicon-rich zeolite,
• e) titanium dioxide which is doped with at least one oxide of a metal of the third to sixth subgroup or an oxide of a lanthanoid including the lanthanum,
• f) a mixture of zirconium dioxide with at least one oxide of a metal of the third to fifth subgroup, at least one oxide of a lanthanoid including the lanthanum or a mixture of one or more of these oxides or
• g) an optionally doped cerium oxide.

The porous Cover layer contains According to the invention additionally at least a catalytically active substance.

As a result of the coating, a surface cover layer which is as closed as possible is produced by which the ceramic filter material, in particular aluminum titanate or cordierite, is protected from the thermochemical attack of exhaust gas components, in particular ashes. This is possible because the ceramic cover layer of the invention, the hydrothermal conditions during driving and during regeneration durable, ie over a vehicle life, resists. The coating according to the invention and the coating process according to the invention are suitable for the overall surface of the filter Finally, as completely as possible to coat the inner pore structure.

A further increase the thermal and hydrothermal stability of alpha, gamma, delta and theta alumina or aluminosilicate, magnesium aluminum silicate, Aluminum titanate and SiC is, for example, doped with at least an oxide of a metal of the 3rd to 5th subgroup or at least an oxide of a lanthanum, including lanthanum or a Mixture of several of these oxides achieved. Likewise, the hydrothermal and thermal stability of alumina hydrate by doping at least one of these oxides elevated, so that such a doped alumina hydrate also suitable as a coating. The proportion of the oxide of a metal of 3rd to 5th subgroup, the oxide of a lanthanoid including the Lanthanum or a mixture of one or more of these oxides in the Alumina or in the alumina hydrate is preferably in Range of 0.5 to 15 wt .-% per oxide.

The aluminum oxides suitable for forming the coating preferably have a BET surface area of more than 1 m ² / g in powder form. The BET surface area is determined by gas adsorption according to Brunauer, Emmet and Teller according to DIN 66131 and ISO 9277. The bulk density of the aluminum oxide is preferably greater than 0.3 g / cm ³ and the pore volume is in the range of 0.2 to 1.3 ml / g. The doped aluminum oxides or mixtures of several aluminum oxides also have corresponding BET surface areas, bulk density and pore volume.

Also by doping with silicon dioxide, the thermal and hydrothermal stability of alpha, gamma, delta and theta alumina, or alumina hydrate increase. The doping of silica may e.g. in the form of a solution, like What serglas, or a sol applied to the alumina or Aluminiumoxidhydratoberfläche become. The proportion of silicon dioxide is preferably in the range from 0.5 to 30% by weight.

Further suitable for the coating is a mixture of zirconium dioxide with one or more oxides of a metal of the 3rd to 5th subgroups, at least one oxide of a lanthanoid, including the lanthanum or a mixture of one or more of these oxides. The proportion of the mixed oxide is preferably in the range of 1 to 60 wt .-% per oxide. The mixed oxides of zirconium dioxide which are suitable for forming the coating preferably have a BET surface area of more than 5 m ² / g in powder form, the BET surface area being determined as already explained above.

Further if silicon dioxide is also suitable for coating the filter substrate, to increase the thermal and hydrothermal stability. Another increase in the thermal and hydrothermal stability is achieved by the silicon oxide at least one oxide of a metal of the 3rd to 5th subgroup or at least one oxide of a lanthanum including the Lanthanum or a mixture of several of these oxides are mixed. The share for each oxide of the metals of the 3rd to 5th subgroup or the lanthanides, including of the lanthanum in the silica is preferably in the range of 1 to 30 wt .-%.

Next particle-form amorphous silica are also silicon-rich zeolites for the coating, especially with an S / A ratio greater than 50, in particular of the type Y, β, ZSM, or mixtures of these or with these for the construction of the coating suitable. The zeolites are preferably in hydrogen form before or with exchanged transition metals, in particular with elements of the 6th to 12th subgroup or mixtures from these.

Next The oxides mentioned titanium dioxide is also suitable for coating of the ceramic filter substrate. A sufficient thermal and hydrothermal stability is achieved in that the titanium dioxide at least one oxide a metal of the 3rd to 6th subgroup or an oxide of a lanthanoid, including of lanthanum, to be mixed. The proportion of at least one Oxides of a metal of the 3rd to 6th subgroup, a lanthanide including lanthanum or a mixture of one or more of these oxides, is preferably 1 to 60 wt .-% per oxide. Especially suitable for admixture The titania are tungsten oxides and vanadium oxides. So is suitable For example, titanium dioxide, which with 4 to 8 wt .-% tungsten oxide and 1 to 5 wt .-% vanadium oxide is doped for coating the substrate.

If the coating contains a cerium oxide, it is preferably doped or mixed with one or more oxides of the elements of the 3rd to 6th subgroups or the lanthanides, including the lanthanum. The proportion of the mixed oxides is preferably in the range of 40 to 95 wt .-%. The cerium oxides and cerium mixed oxides which are suitable for the formation of the coating preferably have a BET surface area of more than 5 m ² / g in powder form.

The optionally doped alumina, the doped alumina hydrate, the silica or silicon-rich zeolite, the titanium dioxide, The zirconia and ceria can be used in any mixture be used for coating the ceramic filter substrate.

Farther contains the porous one Cover according to the invention additionally at least a catalytically active substance. Suitable catalytically active substances are e.g. Precious metals from the group of platinum metals, e.g. Platinum, Rhodium or palladium. these can used both individually and in mixture.

According to the invention of at least one catalytically active substance in the ceramic coating to increase be included in the thermal and hydrothermal stability or the catalytically active Fabric is applied to the filter substrate in a second layer. In this case, the catalytically active layer both first the filter substrate are applied and then the coating for thermal or hydrothermal stabilization or it will be first the coating for thermal or hydrothermal stabilization and subsequently applied the catalytically active layer. It is also possible to alternate Apply several layers, each one catalytically active layer and a layer to improve the thermal and hydrothermal stability alternate.

If the coating consists of only a single layer, so is contain the catalytically active material in this layer. In addition, in the coating still alkali and / or alkaline earth metal oxides and Mixed oxides of these or combinations and mixed oxides of the alkali metal and / or alkaline earth metal oxides with the oxides described above be contained with a mass content of up to 50 wt .-%. In addition, you can also other ceramic or mineral substances such as aluminosilicates, Magnesium aluminosilicates, e.g. Cordierite, silicon carbide or aluminum titanate be included.

In order to the noxious gases, e.g. unused fuel and its decomposition products, e.g. CO and nitrogen oxides, sulfur oxides and soot particles stored and converted by thermal catalytic can be it is necessary that the coating is porous so that the noxious gases or soot particles to the catalytically active material contained in the coating can reach.

to Generation of a catalytically active layer is also the catalytic active material during added to the preparation of the coating material. Suitable for this purpose e.g. Precipitation, sol-gel and pyrolysis procedures alike. Mixtures of the described catalytically active materials both on the same and on different carrier materials be used. It can both mixtures and alloys of these metals are present. The amount of catalytically active material is on the filter volume based and varies depending on the application. Thus, e.g. Using one of the aforementioned oxides or ceramic materials as Trägermaterterial the coating e.g. added up to 4.9 g / l of palladium. Farther it is e.g. suitable, up to 2.8 g / l of platinum optionally with bis to 2.8 g / l of palladium or 0.35 g / l of palladium optionally with bis to 3.2 g / l of platinum and / or palladium as the catalytically active substance to use.

Also the coating becomes, for example, in the form of particles as slip or as a sol by spraying, Diving, watering or similar Coating processes applied to the ceramic filter substrate. Furthermore, vacuum-based coating processes are also suitable.

The average particle size (D 50) the materials suitable for forming the coating varies in a wide range. Particularly suitable are particles of a Size of 2 nm up to 20 μm. The particles can e.g. spherical, needle-shaped, platelet-shaped. Also can these agglomerated, porous, ramified or otherwise three-dimensionally structured particles or mixtures to be from these forms. The particles can be produced, for example, by precipitation processes or pyrolytic processes are recovered. Also grinding processes are suitable to adjust the particle size and the particle size distribution. When the particles through a precipitation process can be generated for example, aluminum and / or zirconium salt solutions and optionally as a supplement, the salt solutions the dopants as precursors be used.

suitable Cover layers are, for example, by combining nanoparticles, i.e. Particles with a mean diameter smaller than 1 μm, and microparticles, i.e. Particles with a mean diameter greater than 1 micron, sometimes with bi or polymodal particle size distribution achieved. in the Generally, the proportion of particles that have a mean diameter of more than 20 μm have less than 20 wt .-%. The nanoparticles and microparticles can both in one shift as well as in two or more consecutive ones Layers are combined with each other.

By the particle size distribution the particles coated on the filter substrate, and the reological properties of the coating composition is suitable this to cover the entire, even inner filter substrate surface. Preferably are called microcracks, i. Cracks within the individual grains of the filter substrate not coated.

The fixation of the ceramic cover layer on the filter substrate is carried out, for example, by drying, calcination and sintering. By variation The amount of ceramic materials to be applied for the formation of the cover layer can vary the thickness of the cover layer. The loading of the filter with the ceramic materials for coating is based on the filter volume and is preferably between 0.61 g / l and 61 g / l, based on the total filter volume.

If the catalytically active material is contained in an additional layer, this layer is preferably also made of optionally doped alumina, doped alumina hydrate, aluminosilicate, magnesium aluminum silicate, aluminum titanate, silicon carbide, silicon dioxide or silicon-rich zeolite, titanium dioxide or zirconium dioxide , as already described above for the coating to increase the thermal and hydrothermal stability, doped .. A suitable particle size for forming the catalytically active layer of the aforementioned oxides is in the range of 1 nm to 15 microns. Optionally, the particle size of the ceramic or oxidic materials suitable for forming the catalytically active layer may be 1 nm to 50 nm. Mixtures of microparticles and nanoparticles in any desired mixing ratio are also suitable for the catalytically active layer. Suitable protective layers are also formed by combining different particles in a polymorphic mixture, sometimes in bi- or polymodal particle size distribution. When using optionally doped alumina or doped alumina hydrate for the protective layer, these preferably have a BET surface area of more than 20 m ² / g in powder form.

at a coating consisting of a coating to increase the thermal or hydrothermal stability and at least one catalytic active layer, is the layer for increasing the thermal or hydrothermal Stability preferably from nanoparticles, i. formed from particles with a mean particle diameter <1 micron and the catalytically active layer is preferably microparticles, i.e. Particles with a mean particle diameter of more than 1 μm educated. The particle sizes of Layers and the filter substrate are preferably selected so that the filtration efficiency at an optimized gas back pressure is increased.

Next the coating of the filter substrate with a catalytically active Coating containing only a catalytically active material or a contains homogeneous mixture of several catalytically active materials is it also possible that individual areas of the filter substrate with a catalytic active layer with different catalytically active material or Mixtures or alloys of these are coated.

Farther it is also possible that individual regions of the filter substrate with different layers, Quantities or layer sequences are coated.

to Production of the coating according to the invention For example, the coating material is applied to the sintered ceramic Filter substrate in the form of particles as a slip or as a sol applied and then fixed by drying, calcining or sintering. When the coating material is doped or contains admixtures, the doping for Example in the form of solutions while the production of the slip or directly before coating the Filter substrates are added to the slurry. It continues also possible that the doping as preformed Topcoat takes place. For this purpose, the preformed cover layers with the solutions the dopants impregnated. This for example, by spraying, Diving, watering or similar, the processes known to those skilled in the art, by which a changed distribution the dopants on the surface is achieved.

The to be mixed for example in the form of solids as oxide, hydroxide or salt, preferably carbonate, nitrate or acetate to be doped coating material be mixed or added as a sol.

If alternating layers to increase the thermal or hydrothermal stability and catalytically active layers are applied, then each first a layer is applied and subsequently dried and optionally calcined or sintered. These methods are from the ceramics industry, the catalyst production and the particle filter manufacturing known. The individual layers become according to the invention consecutively applied. Here each layer is dried separately. To the application and drying of the layers, these are at least a thermal treatment calcined or sintered. The temperature this is 300 to 800 ° C. The duration of the thermal treatment depends on the size of the coating particle filter and is generally 0.5 to 16 Hours.

The coating according to the invention is suitable for all ceramic filter substrates, in particular those having a porosity of 31 to 76%. The specific surface area of the coating according to the invention is preferably greater than 5 m ² / g, particularly preferably greater than 20 m ² / g.

Brief description of the drawings

embodiments The invention is illustrated in the drawings and in the following Description closer explained.

It demonstrate

1 a schematic representation of an internal combustion engine with an exhaust gas aftertreatment according to the invention,

2 a filter element according to the invention in longitudinal section,

3 a schematic representation of the coated filter substrate with a layer,

4 an example of a grain of the filter substrate with a coating in several layers.

Embodiments of the invention

1 shows a schematic representation of an internal combustion engine with an exhaust gas aftertreatment device according to the invention. The exhaust aftertreatment device is here a filter in which soot particles are removed from the exhaust gas flow.

An internal combustion engine 10 is over an exhaust pipe 12 connected in which a filter device 14 is arranged. With the filter device 14 soot particles are out of the exhaust pipe 12 filtered exhaust gas filtered out. This is especially necessary for diesel engines to comply with legal requirements.

The filter device 14 includes a cylindrical housing 16 , in which in the present embodiment, a rotationally symmetrical, also a total cylindrical filter element 18 is arranged.

2 shows a filter element according to the invention in longitudinal section.

The filter element 18 For example, as an extruded molded article of a ceramic material, for example, magnesium-aluminum silicate, preferably cordierite. The filter element 18 will be in the direction of the arrows 20 flows through exhaust gas. The exhaust gas passes over an entrance surface 22 in the filter element 18 and leaves this via an exit surface 24 ,

Parallel to a longitudinal axis 26 of the filter element 18 run several inlet channels 28 in alternation with outlet channels 30 , The entrance channels 28 are at the exit surface 24 locked. In the embodiment shown here are sealing plugs for this purpose 36 intended. Instead of the sealing plugs 36 However, it is also possible that the entrance channels 28 to the exit surface 24 Rejuvenate until the wall of the entrance channel 28 touch and the entrance channel 28 so closed. In this case, the inlet channel 28 in the direction parallel to the longitudinal axis 26 a triangular cross section.

Accordingly, the outlet channels 30 at the exit surface 24 open and in the area of the entrance area 22 locked.

The flow path of the unpurified exhaust gas thus leads into one of the inlet channels 28 and from there through a filter wall 38 in one of the exit channels 30 , This is exemplified by the arrows 32 shown.

In 3 a schematic representation of the coated filter substrate is shown with a layer. A filter wall 38 is made of a ceramic filter substrate. The ceramic filter substrate consists of individual grains 40 which are generally interconnected by sintering. The ceramic filter substrate is preferably silicon carbonate, aluminum titanate or cordierite. Also, mixtures of these materials are possible. Between the individual grains 40 of the ceramic filter substrate are pores 42 , which are flowed through by the gas stream to be purified. Particles contained in the gas stream become from the ceramic filter substrate of the filter wall 38 retained. The particles that are removed from the gas stream also settle in the pores 42 from. This reduces the free cross section of the filter wall 38 and the pressure loss across the filter wall 38 rises. For this reason, it is necessary to remove the particles from the pores at regular intervals. This is generally done by thermal regeneration, in which the filter is heated to a temperature of more than 600 ° C. At this temperature, the usually organic particles burn to carbon dioxide and water and are discharged in gaseous form out of the particle filter.

Since the filter substrate of silicon carbonate, aluminum titanate and / or cordierite is generally not stable against these high temperatures, the individual grains are 40 according to the invention with a coating 44 Mistake. The coating 44 is preferably a ceramic coating which is stable against the high temperatures encountered in the regeneration of the particulate filter. Suitable coating materials are, for example - as already described above - optionally with an oxide of a metal of the third to fifth subgroup, a lanthanoid including lanthanum or a mixture of one or more of these oxides doped alumina, alumina hydrate, which with silica, at least one oxide of a metal of third to fifth subgroup, at least one oxide of a lanthanum including the lanthanum or a Mixture of one or more of these oxides is doped, optionally with an oxide of a metal of the third to fifth subgroup, a lanthanoid including the lanthanum or a mixture of several of these oxides mixed silica or a silicon-rich zeolite, with an oxide of a metal of the third to sixth subgroup or an oxide of a lanthanoid including the lanthanum doped titanium dioxide, a mixture of zirconium dioxide and at least one oxide of a metal of the third to fifth subgroup, at least one oxide of a lanthanoid including the lanthanum or a mixture of one or more of these oxides, ceria or a mixture of several of aforementioned ceramic materials.

According to the invention contains the ceramic coating furthermore at least one catalytically active material. As catalytic active materials are in particular precious metals from the group of Platinum metals, e.g. Platinum. Rhodium or palladium. Through the in The catalytically active material contained in the coating will also Noxious gases and soot particles stored and thermally catalytically implemented. The implementation of Harmful gases are generally exothermic, releasing heat of reaction becomes. This heat of reaction contributes to Achievement of the exhaust gas temperature necessary for the regeneration of the filter at.

By applying the coating material to the sintered ceramic filter substrate generally in the form of particles as a slurry or a sol, and then fixing by drying, calcination or sintering, the surfaces of the grains become 40 the filter substrate of the filter wall 38 including the walls of the pores 42 coated. Preferably, the coating material does not penetrate optionally in the grains 40 contained microcracks 46 one. By coating the microcracks, the durability of the filter can be reduced.

4 shows a grain 40 of the filter substrate with a coating of two layers. In the grain 40 is a micro crack 46 educated.

The corn 40 includes a first layer 48 made of a ceramic material as described above. Through the first layer 40 becomes the thermal and hydrothermal stability of the grain 40 elevated. On the first layer 48 is a second layer 50 applied, which contains a catalytically active material. The second layer 50 It also consists essentially of a ceramic or mineral oxide, in which the catalytically active material is added.

In addition to the in 4 In the illustrated embodiment, it is also possible that the first layer, which increases the thermal and hydrothermal stability, and the second layer 50 that is catalytically active, are reversed, so on the grain 40 first the catalytically active layer and then the layer for increasing the thermal or hydrothermal stability is applied. Furthermore, it is also possible that on the catalytically active layer 50 again a layer is applied to increase the thermal and hydrothermal stability. The number of turns on the grain 40 Applied layers is freely selectable and limited only by the desired pore size remaining after coating.

Claims (14)

Filter for removing particles from a gas stream, in particular of soot particles from an exhaust stream of an internal combustion engine, with a filter body from a ceramic filter substrate, wherein the filter substrate with a porous cover layer is coated and the porous Cover layer contains at least one of the following substances: (A) at least one alumina selected from alpha, gamma, delta and theta alumina, (b) alumina hydrate which is doped is with silicon dioxide, at least one oxide of a metal of the 3. to 5th subgroup, at least one oxide of a lanthanum including the Lanthanum or a mixture of one or more of these oxides, (C) Aluminosilicate, magnesium aluminum silicate or aluminum titanate, (D) Silica or silicon-rich zeolite, (e) titanium dioxide, which with at least one oxide of a metal of the 3rd to 6th subgroup or an oxide of a lanthanum, including the lanthanum, (F) a mixture of zirconium dioxide with at least one oxide of a metal the 3rd to 5th subgroup, at least one oxide of a lanthanoid including of the lanthanum or a mixture of one or more of these oxides or (G) a cerium oxide, which with at least one oxide of a Metal of the 3rd to 6th subgroup or an oxide of a lanthanoid including of the lanthanum is doped, wherein the porous cover layer at least one contains catalytically active substance. Filter according to claim 1, characterized in that the alumina (a) and / or the silica (d) further at least an oxide of a metal of the 3rd to 5th subgroup or at least an oxide of a lanthanum including the lanthanum or a Mixture of several of these oxides contains. Filter according to claim 2, characterized in that the proportion of the oxide or the mixture of several oxides in the alumina in the range of 1 to 20 wt .-% and / or the proportion of each oxide of the metals of the 3rd to 5th subgroup or the lanthanides including the lanthanum in the silica in the range of 1 to 30 wt .-% and / or the proportion of the at least one Oxide of a metal of the 3rd to 5th subgroup or the at least one oxide of a lanthanoid including the lanthanum or the mixture of several of these oxides in the range of 40 to 95 wt .-% is. Filter according to claim 1, characterized in that the oxide of a metal of the 3rd to 6th subgroup, with the titanium dioxide (e) is an oxide of vanadium or tungsten. Filter according to claim 1, characterized in that the silicon-rich zeolite (d) in hydrogen form or with exchanged transition metals, especially metals of the 6th to 12th subgroup is present. Filter according to claim 1, characterized in that the share for each oxide of a metal of the 3rd to 5th subgroup or for each Oxide of a lanthanide including lanthanum in zirconia (f) in the range of 1 to 60 wt .-% is. Filter according to one of claims 1 to 6, characterized that the catalytically active substance platinum, rhodium or palladium is. Filter according to one of claims 1 to 7, characterized the catalytically active material is contained in the porous cover layer. Filter according to one of claims 1 to 7, characterized that the porous one Cover layer at least one ceramic protective layer and at least a catalytically active layer, wherein on the filter substrate first the catalytically active layer and then the protective layer or first the protective layer and then the catalytically active layer applied can be. Filter according to claim 9, characterized in that that the catalytically active layer contains at least one of the substances the the porous one Form cover layer, and contains at least one catalytically active material. Filter according to one of claims 1 to 10, characterized that individual regions of the filter substrate with a catalytic active layer with different catalytically active material or Mixtures or alloys of these are coated. Filter according to one of claims 1 to 11, characterized that individual areas of the filter substrate with different Layers, quantities or layer sequences are coated. Method for producing a filter according to one the claims 1 to 12, characterized in that the sintered ceramic Filter substrate, the coating material in the form of particles as Slip or applied as a sol and then by drying, calcination or sintering is fixed and for the catalytically active layer of the at least one catalytically active Substance by a precipitation, sol-gel or pyrolysis method applied to the coating material becomes. Method according to claim 13, characterized in that that the particles contained in the slurry for the protective layer have a middle Have diameter smaller than 1 micron and contained in the slurry Particles for the catalytically active layer has an average diameter, the greater than 1 μm.