CN111389396A

CN111389396A - Carbon smoke removing catalyst and preparation method and application thereof

Info

Publication number: CN111389396A
Application number: CN202010166723.4A
Authority: CN
Inventors: 刘爽; 梁瀚颖; 柳伟
Original assignee: Ocean University of China
Current assignee: Ocean University of China
Priority date: 2020-03-10
Filing date: 2020-03-10
Publication date: 2020-07-10
Anticipated expiration: 2040-03-10
Also published as: CN111389396B

Abstract

The invention discloses a carbon smoke removing catalyst, which comprises yttria-stabilized zirconia nanofibers and is characterized in that the nanofibers have a secondary pore structure, namely ultra-large pores among fibers and large pores on the surfaces of the fibers. The yttria is stabilizedThe surface of the zirconia nanofiber and the macroporous structure on the surface of the zirconia nanofiber are uniformly distributed with nano Ag particles. According to the invention, a silver-loaded yttrium oxide stabilized zirconia material (Ag/YSZ) is prepared into the nanofiber with a secondary pore channel structure by adding a pore-forming agent to carry out electrostatic spinning technology and combining a process of removing an embedded template through high-temperature oxidation and calcination. The catalyst has good catalytic activity, and has super-large pores capable of filling carbon smoke clusters and large pores capable of matching carbon smoke particles, so that the catalyst can be fully contacted with carbon smoke, and the contact property of the carbon smoke and the catalyst is improved. In the presence of the catalyst, to simulate the exhaust gas atmosphere of a motor vehicle, at a temperature at which the soot can be converted to 50: (T ₅₀) The temperature is reduced to below 430 ℃, and the method has great application value.

Description

Carbon smoke removing catalyst and preparation method and application thereof

Technical Field

The invention belongs to the technical field of flue gas purification, and particularly relates to a tail gas soot removal catalyst, and a preparation method and application thereof.

Background

With the rapid increase of the number of global automobiles, automobile exhaust gradually becomes a primary pollution source of atmospheric pollution emission. Particulate matter contained in the exhaust gas, particularly particulate matter having a diameter of less than 10 μm (PM 10), is highly carcinogenic and if left uncontrolled, can pose a serious threat to human health. Currently, installing a particulate filter in an exhaust pipe of a motor vehicle is an effective and economical technique for treating PM. The technology mainly uses an oxidation catalyst (mainly a material containing noble metal platinum) in a filter to oxidize the trapped soot (main component of PM) into relatively harmless CO in an exhaust gas environment₂. In recent years, with the increase in the price of precious metals and the improvement in the emission standards of exhaust gases, the development of cheaper and more efficient soot oxidation catalysts is imperative.

Yttria-stabilized zirconia (YSZ) is a novel class of catalytic oxidation materials. The introduction of yttrium oxide can stabilize zirconium oxide into cubic fluorite structure, and Y is used³⁺With Zr⁴⁺The material has high oxygen supply capacity due to the generation of a large amount of oxygen ion vacancies in the zirconia crystal by non-equivalent replacement. Recently, some researchers found that when metal particles (such as silver) with a low work function are loaded on YSZ, zirconia lattice oxygen can be "pumped" out to the surface of YSZ through the Cabrera-Mott effect to participate in catalytic reaction, thereby significantly enhancing the catalytic oxidation performance. For example, Serve et al examined different contents of silver supported on various types of oxide Supports (SiO)₂、ZrO₂、Ce_xZr_1-xO₂YSZ, etc.), the Ag/YSZ samples containing 4% silver were found to have the best soot oxidation performance (temperature at 50% soot removal)T ₅₀Around 460 ℃). It is worth noting that, the carbon smoke clusters (with the size larger than 100 nm) and the particles (with the size of about 10-100 nm) can not enter the pores on the surface of the catalyst,the oxidation process is therefore closely related to the soot-catalyst contact. The granular nano-Ag/YSZ catalyst has limited contact with soot due to the existence of self-cluster aggregation. This makes the intrinsic catalytic performance of the material not fully embodied (T ₅₀Hardly reduced to below 430 ℃), and can not fully meet the requirements of gradually strict tail gas emission regulations in China.

Compared with the granular nano catalyst, the nano fiber catalyst can better match with the morphology of the carbon smoke cluster and obtain more catalyst-carbon smoke contact sites due to the multi-stage super macroporous structure generated in the overlapping process. For example, Bensaid et al found nano-fibrillar CeO₂Burning sootT ₅₀Compared with other nanometer CeO₂The catalyst is 50-70 ℃ lower^[8]In addition, compared with other nano materials, YSZ nano fiber has the advantages of high temperature resistance, simple synthesis method, easy large-scale production and the like, and the coating of the YSZ nano fiber on the surface of a filter can be realized by combining an electrostatic spinning method with a sol-gel method at low cost [ Chengli Rong, Li Wei, XiuLing]. It should be noted that although the ordinary nanofiber catalyst can effectively contact with the soot cluster, the fiber surface is smooth and non-porous, which makes it difficult to achieve nano-scale contact with each soot particle. This phase change reduces the number of contact sites with soot for such catalysts, making it difficult to burn the soot even with the aid of a silver componentT ₅₀Effectively reduces the temperature below 430 ℃ (L ee, Chanmin, Joo-Ilpark, Yong-Gun Shul, et al, Ag supported on electrospun macro-structure CeO₂fibrous mats for diesel soot oxidation. Applied Catalysis B: Environmental,2015, 174: 185-192]There is room for further improvement in this structure.

In summary, if a novel catalytic material (such as Ag/YSZ) with low cost and high performance can be selected, and the catalyst structure is reasonably designed to enhance the contact property with soot, the existing soot removal efficiency limit (soot combustion) is expected to be broken throughT ₅₀Reduced to below 430 ℃) for reducing the emission of particulate matters in the automobile exhaust in ChinaA contribution.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a soot removal catalyst which is inexpensive, has good catalytic activity, improves the contact of soot with the catalyst, and can achieve efficient removal of soot particles at low temperatures (< 430 ℃).

Another object of the present invention is to provide a simple and efficient method for preparing the above soot removal catalyst.

The invention prepares the silver-loaded yttria-stabilized zirconia material (Ag/YSZ) into the nanofiber with a secondary pore channel structure by adding a pore-forming agent to carry out electrostatic spinning technology and combining a process of removing an embedded template by high-temperature oxidation and calcination: including the porosity between the fibers and the pore structure of the fiber surface. The catalyst adopts a YSZ carrier with strong oxygen-conducting capability activated by a silver component, and has strong intrinsic oxidation performance; the fibrous integral structure is helpful for matching the catalyst with the soot cluster, and the macropores on the surface of the fiber carrier can effectively contact with single soot particles, so that the number of active sites for oxidizing the soot by the catalyst is increased. The material components and the secondary pore structure of the catalyst act together to realize the high-efficiency removal of low-temperature (< 430 ℃) soot particles. In addition, components such as silver, yttrium oxide, zirconium oxide and the like are not expensive materials, so the material cost of the catalyst is far lower than that of a commercial platinum-based catalyst.

In order to achieve the purpose, the invention adopts the following specific technical scheme:

a carbon smoke removing catalyst comprises yttria-stabilized zirconia nanofibers and is characterized in that the yttria-stabilized zirconia nanofibers have a secondary pore structure, namely ultra-large pores among fibers and a large pore structure on the fiber surface, and nano Ag particles are uniformly distributed on the surface of the yttria-stabilized zirconia nanofibers and in the large pore structure on the fiber surface.

The diameter of the yttria-stabilized zirconia fiber is 100-5000 nm, and the ultra-large pore space between fibers is 1000-5000 nm; the pore diameter of the macroporous structure on the surface of the yttria-stabilized zirconia fiber is 10-200 nm.

The preparation method of the soot removal catalyst is characterized by comprising the following steps of:

(1) preparing a spinning solution: weighing a proper amount of zirconium salt and a zirconium oxide crystal phase stabilizer, mixing, adding a proper amount of solvent, stirring at room temperature until the zirconium salt and the zirconium oxide crystal phase stabilizer are completely dissolved, finally adding a pore-forming agent and a high-molecular polymer, and stirring at room temperature until the zirconium salt and the zirconium oxide crystal phase stabilizer are fully mixed;

(2) preparing electrostatic spinning: adding the spinning solution obtained in the step (1) into electrostatic spinning equipment, and externally applying a certain electric field intensity to carry out electrostatic spinning to obtain spinning fibers;

(3) and (3) heat treatment: calcining the spinning fiber obtained in the step (2) in an air atmosphere to obtain porous zirconia fiber;

(4) carrying silver components: preparing a proper amount of silver salt into a solution, dipping the porous zirconia fiber obtained in the step (3) to enable the surface of the fiber and the inside and outside of the macropores to be uniformly loaded with the silver salt, fully stirring to enable the silver salt and the macropores to be uniformly mixed, then drying and calcining, and finally preparing the carbon smoke removal catalyst.

Further, in the step (1), the zirconium salt is zirconium acetate, the zirconium oxide crystal phase stabilizer is yttrium nitrate hexahydrate, and the mass ratio of zirconium acetate to yttrium nitrate hexahydrate is 10: 1-20: 1.

Further, in the step (1), the solvent is one or any combination of several of deionized water, ethanol, N-N dimethylformamide and ethylene glycol; the molar ratio of the solvent to the zirconium salt is 2: 1-10: 1.

Further, in the step (1), the pore-forming agent is carbon spheres with the particle size of 100 nm-1 μm; the molar ratio of the pore-forming agent to the zirconium salt is 2: 1-4: 1.

Further, in the step (1), the high molecular polymer is polyvinylpyrrolidone having a weight average molecular weight of M_wAnd (4) 1300000, wherein the mass ratio of the high-molecular polymer to the zirconium salt is 1: 30-1: 50.

Further, in the step (2), the specific conditions of electrostatic spinning are as follows: the voltage is 15-25 kV; the distance between the receiving screen and the needle head is 10-15 cm; the propelling speed is 0.2-6 ml/h; the diameter of the needle head is 0.3-0.7 mm; the environment temperature is 20-30 ℃ and the humidity is 30-50%.

Further, in the step (3), the calcining temperature is 600-800 ℃, the calcining time is 2 hours, and the calcining temperature rise rate is controlled to be 2-5 ℃/min.

Further, in the step (4), the silver salt is silver nitrate, and the mass ratio of the silver salt to the yttrium nitrate-stabilized zirconia is 1: 20.

Further, in the step (4), the calcination temperature is 500 ℃, the calcination time is 2 hours, and the calcination temperature rise rate is controlled to be less than 2 ℃ per minute.

The invention has the beneficial effects that: the components of silver, yttrium oxide, zirconium oxide and the like do not belong to noble metal materials, so the material cost of the catalyst is far lower than that of a commercial platinum-based catalyst; the silver-loaded porous yttria-stabilized zirconia has good catalytic activity, and meanwhile, the porous zirconia fiber material has super-large pores capable of filling soot clusters and large pores capable of being matched with soot particles, so that the material can be fully contacted with soot, and the contact between the soot and a catalyst is improved. In the presence of the catalyst, to simulate the exhaust gas atmosphere of a motor vehicle, at a temperature at which the soot can be converted to 50: (T ₅₀) The temperature is reduced to below 430 ℃, and the method has great application value.

Drawings

FIG. 1 is a scanning electron micrograph of the material prepared in example 1 of the present invention.

FIG. 2 is a scanning electron micrograph of the material prepared in example 2 of the present invention.

FIG. 3 is a scanning electron micrograph of the material prepared in example 3 of the present invention.

FIG. 4 is a scanning electron micrograph of the material prepared in example 4 of the present invention.

FIG. 5 is a scanning electron micrograph of the material prepared in example 5 of the present invention.

FIG. 6 is a scanning electron micrograph of a material prepared according to comparative example 1 of the present invention.

FIG. 7 is a scanning electron micrograph of a material prepared according to comparative example 2 of the present invention.

FIG. 8 is a graph comparing soot conversion rates of comparative examples 1 to 2 and examples 1 to 5 of the present invention.

FIG. 9 is an XRD characterization chart of comparative examples 1-2 and examples 1-5 of the present invention.

FIG. 10 is a graph showing the pore structure in examples 1 to 5 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described by the following specific examples in conjunction with the comparative examples and the accompanying drawings, but the scope of the present invention should not be limited thereby.

Example 1:

weighing 2 ml of zirconium acetate containing 15-16% of zirconium and 0.193 g of yttrium nitrate, adding 0.7 ml of ethanol and 0.7 ml of N-N dimethylformamide, stirring at room temperature until the mixture is completely dissolved, then adding 0.15 g of carbon spheres with the diameter of about 100nm, 0.15 g of carbon spheres with the diameter of about 400 nm and 0.18 g of polyvinylpyrrolidone, and stirring to uniformly mix the components. And adding the spinning solution into a disposable injector with a spinning needle, externally applying an electric field intensity of 20.5 kV, enabling the distance between a receiving screen and the spinning needle to be 10 cm and the spinning needle to be 25G, and obtaining the filamentous YSZ fiber. And heating the fiber to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 hours to obtain the porous YSZ fiber. An appropriate amount of silver salt was prepared into a solution, which was immersed on the fiber surface and the inner and outer surfaces of the macropores in equal volume (5 wt.% Ag loading). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded porous YSZ fiber sample.

By adopting electrostatic spinning and pore-forming technology for removing an embedded template, the fibrous Ag/YSZ catalyst with the secondary pore channel structure prepared by the invention has a super-large pore matched with carbon smoke cluster particles and a large pore structure matched with single carbon smoke particles. As can be seen from a scanning electron microscope figure 1 and a pore structure characterization figure 10, the material is a three-dimensional network structure, and a large number of pore structures are distributed on fibers. The diameter of the fibers is 100-500 nm, the gaps among the fibers are 1000-5000 nm, the pore diameter of the macropores in the fibers is 10-200 nm, and the series of secondary pore channel structures can enable the catalyst to be well matched with soot clusters and fully contact with single soot particles. In addition, the XRD pattern of FIG. 9 shows diffraction peaks of metallic Ag, and the size of Ag particles is calculated to be 3 nm or less from the width of the diffraction peaks. This indicates that the silver component of the catalyst is present on the surface of the YSZ fiber (including inside and outside the macropores) in the form of nano-Ag particles. Their presence may further improve the efficiency of the catalyst for catalytic removal of soot using oxygen.

The prepared catalyst sample is subjected to laboratory simulation gas distribution evaluation, and the sample used in the evaluation process is formed by mixing the catalyst, the soot and the quartz sand according to the weight ratio of 100 mg to 10 mg to 300 mg. The mixed sample was placed in a quartz reaction tube having a diameter of 10 mm. Soot oxidation test 1% O with reaction atmosphere of 500 ml/min₂/N₂(space velocity 100000 h^-1). The temperature range of the activity test is 30-700 ℃, and the heating rate is 5 ℃/min. During the reaction, the temperature controller controls the electric furnace to raise the temperature, and the infrared spectrometer measures CO during the reaction₂The resulting concentrations, the conversion of the samples to soot oxidation at different temperatures are shown in figure 8. Obviously, the Ag/YSZ fibrous catalyst with the secondary pore channel structureT ₅₀(temperature at 50% soot conversion) can be lowered to 373 ℃.

Example 2:

weighing 2 ml of zirconium acetate containing 15% -16% of zirconium and 0.193 g of yttrium nitrate, adding 0.7 ml of ethanol and 0.7 ml of N-N dimethylformamide, stirring at room temperature until the mixture is completely dissolved, then adding 0.3 g of carbon spheres with the diameter of about 400 nm and 0.18 g of polyvinylpyrrolidone, and stirring to uniformly mix the carbon spheres and the polyvinylpyrrolidone. And adding the spinning solution into a disposable injector with a spinning needle, externally applying an electric field intensity of 20.5 kV, enabling the distance between a receiving screen and the spinning needle to be 10 cm and the spinning needle to be 25G, and obtaining the filamentous YSZ fiber. And heating the fiber to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 hours to obtain the porous YSZ fiber. After the water absorption of the fiber was measured, an appropriate amount of silver salt was formulated into a solution and immersed in the surface and inner and outer surfaces of the macropores at equal volumes (5 wt.% Ag loading). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded porous YSZ fiber sample.

As can be seen from a scanning electron microscope figure 2, the diameter of the fiber is 200 nm-5 μm, and the secondary pore diameter is 50-100 nm. By the fact thatLaboratory simulated gas evaluation system, method for testing sameT ₅₀Is 413 ℃. Experiments show that the diameter of YSZ fiber is thickened by simply adding large-size pore-forming agent (carbon spheres), and the total amount of secondary pore channels (especially ultra-large pores between fibers) is reduced.

Example 3:

weighing 2 ml of zirconium acetate containing 15% -16% of zirconium and 0.193 g of yttrium nitrate, adding 0.7 ml of ethanol and 0.7 ml of N-N dimethylformamide, stirring at room temperature until the mixture is completely dissolved, then adding 0.3 g of carbon spheres with the diameter of about 100nm and 0.18 g of polyvinylpyrrolidone, and stirring to uniformly mix the carbon spheres and the polyvinylpyrrolidone. And adding the spinning solution into a disposable injector with a spinning needle, externally applying an electric field intensity of 20.5 kV, enabling the distance between a receiving screen and the spinning needle to be 10 cm and the spinning needle to be 25G, and obtaining the filamentous YSZ fiber. And heating the fiber to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 hours to obtain the porous YSZ fiber. After the water absorption of the fiber was measured, an appropriate amount of silver salt was formulated into a solution and immersed in the surface and inner and outer surfaces of the macropores at equal volumes (5 wt.% Ag loading). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded porous YSZ fiber sample.

As can be seen from a scanning electron microscope image 3, the diameter of the fiber is 300 nm-3 μm, and the secondary pore diameter is 50-100 nm. By laboratory simulation of gas evaluation systems, measuredT ₅₀Is 414 ℃. Experiments show that the diameter of YSZ fiber is also thickened by simply adding small-sized pore-forming agent (carbon spheres), and the total amount of secondary pore channels (especially ultra-large pores between fibers) is reduced.

Example 4:

weighing 2 ml of zirconium acetate containing 15% -16% of zirconium and 0.193 g of yttrium nitrate, adding 0.3 ml of water, stirring at room temperature until the zirconium acetate is completely dissolved, then adding 0.203 g of carbon spheres with the diameter of about 400 nm and 0.16 g of polyvinylpyrrolidone, and stirring to uniformly mix the carbon spheres and the polyvinylpyrrolidone. And adding the spinning solution into a disposable injector with a spinning needle, externally applying an electric field intensity of 20.5 kV, enabling the distance between a receiving screen and the spinning needle to be 10 cm and the spinning needle to be 25G, and obtaining the filamentous YSZ fiber. And heating the fiber to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 hours to obtain the porous YSZ fiber. After the water absorption of the fiber was measured, an appropriate amount of silver salt was formulated into a solution and immersed in the surface and inner and outer surfaces of the macropores at equal volumes (5 wt.% Ag loading). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded porous YSZ fiber sample.

As can be seen from a scanning electron microscope figure 4, the diameter of the fiber is 200 nm-4 μm, and the secondary pore diameter is 50-200 nm. By laboratory simulation of gas evaluation systems, measuredT ₅₀Is 423 ℃. Experiments have shown that the use of water alone as a solvent results in very non-uniform fiber diameters and a substantial reduction in the total number of secondary channels (especially interfiber macropores).

Example 5:

2 ml of zirconium acetate containing 15 to 16 percent of zirconium and 0.193 g of yttrium nitrate are weighed, 0.3 ml of N-N dimethylformamide is added and stirred at room temperature until the zirconium acetate is completely dissolved, and then 0.3 g of carbon spheres with the diameter of about 400 nm and 0.18 g of polyvinylpyrrolidone are added and stirred to be uniformly mixed. And adding the spinning solution into a disposable injector with a spinning needle, externally applying an electric field intensity of 20.5 kV, enabling the distance between a receiving screen and the spinning needle to be 10 cm and the spinning needle to be 25G, and obtaining the filamentous YSZ fiber. And heating the fiber to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 hours to obtain the porous YSZ fiber. After the water absorption of the fiber was measured, an appropriate amount of silver salt was formulated into a solution and immersed in the surface and inner and outer surfaces of the macropores at equal volumes (5 wt.% Ag loading). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded porous YSZ fiber sample.

As can be seen from a scanning electron microscope figure 5, the diameter of the fiber is 400 nm-4 μm, and the secondary pore diameter is 50-100 nm. By laboratory simulation of gas evaluation systems, measuredT ₅₀At 396 ℃. Experiments show that the fiber diameter is thickened by only using N-N dimethylformamide as a solvent.

Comparative example 1:

2 ml of zirconium acetate containing 15 to 16 percent of zirconium and 0.193 g of yttrium nitrate are weighed, 0.7 ml of ethanol and 0.7 ml of N-N dimethylformamide are added, stirring is carried out at room temperature until the mixture is completely dissolved, then 0.18 g of polyvinylpyrrolidone is added, and stirring is carried out to ensure that the components are uniformly mixed. And adding the spinning solution into a disposable injector with a spinning needle, externally applying an electric field intensity of 20.5 kV, enabling the distance between a receiving screen and the spinning needle to be 10 cm and the spinning needle to be 25G, and obtaining the filamentous YSZ fiber. And heating the fiber to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 hours to obtain the porous YSZ fiber. After measuring the water absorption of the fiber, an appropriate amount of silver salt was formulated into a solution and immersed on its surface in equal volume (Ag loading 5 wt.%). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded non-porous YSZ fiber sample.

As can be seen from a scanning electron microscope shown in FIG. 6, the diameter of the fiber is 200-600 nm, and no secondary pore structure exists. By laboratory simulation of gas evaluation systems, measuredT ₅₀Is 433 ℃. Experiments show that the catalytic performance of the Ag/YSZ fiber catalyst without the secondary pore channel structure is obviously lower than that of the Ag/YSZ fiber catalyst with the secondary pore channel structure.

Comparative example 2:

2 ml of zirconium acetate containing 15 to 16 percent of zirconium and 0.193 g of yttrium nitrate are weighed and mixed evenly by ultrasonic treatment. And after drying, heating the porous amorphous YSZ to 800 ℃ at 5 ℃/min in the air atmosphere, and preserving heat for 2 h to obtain the porous amorphous YSZ. After measuring its water absorption, an appropriate amount of silver salt was formulated into a solution and immersed on its surface in equal volume (5 wt.% Ag loading). And (3) after drying, heating the sample to 500 ℃ at 2 ℃/min in the air atmosphere, and cooling in a furnace to obtain the silver-loaded porous YSZ sample.

As can be seen from the scanning electron microscope in FIG. 7, the prepared sample has an amorphous porous structure. By laboratory simulation of gas evaluation systems, measuredT ₅₀Is 472 ℃. Experiments show that the catalytic performance of the amorphous porous YSZ is obviously lower than that of a fibrous Ag/YSZ catalyst and a fibrous Ag/YSZ catalyst with a secondary pore channel structure.

Claims

1. A carbon smoke removing catalyst comprises yttria-stabilized zirconia nanofibers and is characterized in that the yttria-stabilized zirconia nanofibers have a secondary pore structure, namely ultra-large pores among fibers and a large pore structure on the fiber surface, and nano Ag particles are uniformly distributed on the surface of the yttria-stabilized zirconia nanofibers and in the large pore structure on the fiber surface.

2. A soot removal catalyst as claimed in claim 1, characterized in that the yttria-stabilized zirconia fibers have a diameter of 100-5000 nm, and the macropore gaps between the fibers are 1000-5000 nm; the pore diameter of the macroporous structure on the surface of the yttria-stabilized zirconia fiber is 10-200 nm.

3. A method for preparing the soot removal catalyst of claim 1, characterized in that it comprises the steps of:

4. The preparation method according to claim 3, wherein in the step (1), the zirconium salt is zirconium acetate, the zirconium oxide crystal phase stabilizer is yttrium nitrate hexahydrate, and the mass ratio of zirconium acetate to yttrium nitrate hexahydrate is 10: 1-20: 1.

5. The preparation method according to claim 3, wherein in the step (1), the solvent is one or any combination of deionized water, ethanol, N-dimethylformamide and ethylene glycol; the molar ratio of the solvent to the zirconium salt is 2: 1-10: 1.

6. The preparation method according to claim 3, wherein in the step (1), the pore-forming agent is carbon spheres with the particle size of 100 nm-1 μm; the molar ratio of the pore-forming agent to the zirconium salt is 2: 1-4: 1.

7. The method according to claim 3, wherein in the step (1), the high molecular weight polymer is polyvinylpyrrolidone having a weight average molecular weight of M_wAnd (4) 1300000, wherein the mass ratio of the high-molecular polymer to the zirconium salt is 1: 30-1: 50.

8. The preparation method according to claim 3, wherein in the step (2), the specific conditions of the electrostatic spinning are as follows: the voltage is 15-25 kV; the distance between the receiving screen and the needle head is 10-15 cm; the propelling speed is 0.2-6 ml/h; the diameter of the needle head is 0.3-0.7 mm; the environment temperature is 20-30 ℃ and the humidity is 30-50%.

9. The preparation method according to claim 3, wherein in the step (3), the calcination temperature is 600 to 800 ℃, the calcination time is 2 hours, and the calcination temperature rise rate is controlled to be 2 to 5 ℃/min.

10. The production method according to claim 3, characterized in that in the step (4), the silver salt is silver nitrate, and the mass ratio of the silver salt to the yttrium nitrate-stabilized zirconia is 1: 20.