Porous silicon carbide material and preparation method thereof

Abstract

The present invention relates to a porous silicon carbide material and a preparation method thereof. The preparation method of the porous silicon carbide material comprises: using porous carbon as a carrier, introducing a protective gas and a gaseous silicon source to perform chemical vapor deposition to obtain a first intermediate; continuing to introduce the protective gas and calcining the first intermediate to obtain a second intermediate; removing the elemental carbon and / or elemental silicon in the second intermediate to obtain the porous silicon carbide material. In the preparation method of the present invention, the gaseous silicon source can be in-situ decomposed into amorphous nano-silicon inside the porous carbon, and then during the calcination process, the nano-silicon will react with the carbon in-situ to form a silicon carbide skeleton, so that the obtained porous silicon carbide material basically retains the skeleton structure of the porous carbon. Therefore, the preparation method of the present invention can effectively control the pore structure of the porous silicon carbide material, and can select porous carbon with different pore structures as templates to control the preparation of porous silicon carbide materials with different pore structures.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, in particular to a porous silicon carbide material and a preparation method thereof. Background Art

[0002] Currently, the preparation methods of porous silicon carbide include organosilicon cracking, carbon thermal reaction, electrochemical etching, magnesium thermal reduction, nano-coating, etc. However, these methods cannot stably control the morphology of the material.

[0003] The template method uses porous carbon as a template, which can borrow the skeleton of porous carbon to retain the carbon skeleton structure while preparing porous silicon carbide. However, when currently using the template method to prepare porous silicon carbide, porous carbon is mainly used as a template. SiO is vaporized by high-temperature heating and then infiltrated into the porous carbon, reacting with carbon to obtain porous silicon carbide. During the reaction between SiO and carbon, C is consumed and CO2 is produced, which destroys the skeleton structure of the porous carbon, causing the porous carbon skeleton structure to collapse easily, and the pore structure of the obtained silicon carbide material cannot be controlled. Summary of the Invention

[0004] Based on this, it is necessary to provide a mesoporous porous silicon carbide material and a preparation method thereof to address the above problems, wherein the preparation method can effectively control the pore structure of the porous silicon carbide material.

[0005] The present invention provides a method for preparing a porous silicon carbide material, comprising the following steps:

[0006] Using porous carbon as a carrier, a protective gas and a gaseous silicon source are introduced to perform chemical vapor deposition to obtain a first intermediate;

[0007] Continue to introduce protective gas and calcine the first intermediate to obtain a second intermediate;

[0008] The elemental carbon and / or elemental silicon in the second intermediate is removed to obtain a porous silicon carbide material.

[0009] In one embodiment, the porous carbon is selected from at least one of pitch-based porous carbon, biomass-based porous carbon, and resin-based porous carbon.

[0010] In one embodiment, the porous carbon satisfies at least one of the following conditions:

[0011] (1) Specific surface area of 50m² / g-2300m² / g;

[0012] (2) Pore volume is 0.1cm³ / g-5.0cm³ / g;

[0013] (3) The pore size is 1nm-1μm.

[0014] In one embodiment, the step of introducing a protective gas and a vapor-phase silicon source to perform chemical vapor deposition satisfies at least one of the following conditions:

[0015] (1) The gas-phase silicon source is selected from at least one of monosilane, ethylsilane or silicon tetrachloride;

[0016] (2) Temperature is 450℃-800℃;

[0017] (3) The flow ratio of the vapor-phase silicon source to the protective gas is 0.1:1-1:0.1;

[0018] (4) The protective gas is selected from at least one of nitrogen and argon.

[0019] In one embodiment, the step of introducing a protective gas and a vapor-phase silicon source to perform chemical vapor deposition satisfies at least one of the following conditions:

[0020] (1) Temperature is 500℃-600℃;

[0021] (2) The flow ratio of the gas-phase silicon source to the protective gas is 1:1-5:1.

[0022] In one embodiment, in the step of calcining the first intermediate, the temperature is 800° C.-2000° C. and the time is 0.5 h-10 h.

[0023] In one embodiment, in the step of calcining the first intermediate, the temperature is 800° C.-1100° C. and the time is 5 h-7 h.

[0024] In one embodiment, the step of removing elemental carbon from the second intermediate includes: placing the second intermediate in an aerobic environment for calcination, wherein the heating rate is 0.5°C / min-10°C / min, the calcination temperature is 800°C-2000°C, and the calcination time is 0.5h-10h.

[0025] In one embodiment, the step of removing elemental silicon from the second intermediate comprises: placing the second intermediate in a strong base or hydrofluoric acid solution for reaction.

[0026] The present invention also provides a porous silicon carbide material prepared by the method for preparing the porous silicon carbide material.

[0027] In the preparation method of the present invention, when porous carbon is used as a carrier and protective gas and a gaseous silicon source are introduced for chemical vapor deposition, the gaseous silicon source can be in situ decomposed into amorphous nano-silicon inside the porous carbon. Then, during the calcination process, the nano-silicon reacts with the carbon in situ to form a silicon carbide skeleton. During the reaction, C is not consumed to produce CO2, so this method basically does not destroy the skeleton structure of the porous carbon. Then, by removing the unreacted elemental silicon and / or elemental carbon, a porous silicon carbide material can be obtained, and the porous silicon carbide material basically retains the skeleton structure of the porous carbon. Therefore, the preparation method of the present invention can effectively control the pore structure of the porous silicon carbide material, and porous carbon with different pore structures can be selected as a template to control the preparation of porous silicon carbide materials with different pore structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is the SEM spectrum of the biomass-based porous carbon in Example 1;

[0030] Figure 2 This is the SEM spectrum of the porous silicon carbide material prepared in Example 1;

[0031] Figure 3 This is the XRD spectrum of the porous silicon carbide material prepared in Example 1;

[0032] Figure 4 This is the TEM spectrum of the porous silicon carbide material prepared in Example 1;

[0033] Figure 5 This is the SEM spectrum of the resin-based porous carbon in Example 2;

[0034] Figure 6 This is the SEM spectrum of the porous silicon carbide material prepared in Example 2;

[0035] Figure 7 This is the XRD spectrum of the porous silicon carbide material prepared in Example 2;

[0036] Figure 8 This is the TEM spectrum of the porous silicon carbide material prepared in Example 2. DETAILED DESCRIPTION

[0037] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments or embodiments and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, including any two related listed items, any more related listed items, or the combination of all related listed items.

[0039] In the present invention, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0040] The method for preparing the porous silicon carbide material provided by the present invention comprises the following steps:

[0041] S1, using porous carbon as a carrier, introducing protective gas and gaseous silicon source to perform chemical vapor deposition to obtain a first intermediate;

[0042] S2, continuing to introduce the protective gas and calcining the first intermediate to obtain a second intermediate;

[0043] S3, removing the elemental carbon and / or elemental silicon in the second intermediate to obtain a porous silicon carbide material.

[0044] In step S1, when chemical vapor deposition is performed using a vapor-phase silicon source with porous carbon as a carrier under a protective atmosphere, the vapor-phase silicon source can be in situ decomposed into amorphous nano-silicon particles inside the porous carbon. The nano-silicon particles can be evenly distributed in the porous carbon due to their extremely small particle size and high specific surface area.

[0045] Furthermore, during the calcination treatment process in step S2, the nano-silicon particles will react in situ with the carbon in the porous carbon skeleton to form a silicon carbide skeleton. No C will be consumed to produce CO2 during the reaction process, so the reaction process of this method will basically not destroy the skeleton structure of the porous carbon. The unreacted elemental silicon and / or elemental carbon are then removed through step S3 to obtain a porous silicon carbide material, and the obtained porous silicon carbide material basically retains the skeleton structure of the porous carbon.

[0046] Therefore, the preparation method of the present invention can effectively control the pore structure of the porous silicon carbide material, and can select porous carbon with different pore structures as a template to control the preparation of porous silicon carbide materials with different pore structures.

[0047] The present invention does not limit the selection of porous carbon. Preferably, the porous carbon in step S1 is selected from at least one of pitch-based porous carbon, biomass-based porous carbon, and resin-based porous carbon.

[0048] Among them, the specific surface area of the porous carbon is preferably 50m² / g to 2300m² / g, the pore volume is preferably 1.0cm³ / g to 5.0cm³ / g, and the pore size is preferably 1nm to 1μm. Therefore, by selecting porous carbon with different pore structures as templates, porous silicon carbide materials with different pore structures can be prepared in a controlled manner, especially silicon carbide materials with a mesoporous structure can be prepared in a controlled manner.

[0049] In step S1, in the step of introducing a protective gas and a vapor-phase silicon source for chemical vapor deposition, the vapor-phase silicon source is selected from at least one of monosilane, ethylsilane, or silicon tetrachloride, and the protective gas is selected from at least one of nitrogen or an inert gas, and the inert gas can be selected from argon, etc. The flow ratio of the vapor-phase silicon source to the protective gas is preferably 0.1:1 to 1:0.1, more preferably 1:1 to 5:1. Specifically, the flow ratio of the vapor-phase silicon source to the protective gas includes but is not limited to 1:1, 2:1, 3:1, 4:1, 5:1, etc., which is more conducive to the deposition effect of nano-silicon particles.

[0050] Furthermore, the temperature in the chemical vapor deposition step is preferably 450°C to 800°C, further preferably 450°C to 750°C, and more preferably 500°C to 600°C, including but not limited to 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, etc., which can also be more conducive to the deposition effect of nano-silicon particles.

[0051] In step S2, in the step of calcining the first intermediate, the temperature is preferably 800°C-2000°C, more preferably 800°C-1100°C, including but not limited to 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, etc., and the time is preferably 0.5h-10h, more preferably 5h-7h, including but not limited to 5h, 5.5h, 6h, 6.5h, 7h, etc., which is conducive to the full reaction of nano-silicon particles and carbon.

[0052] In step S3, a carbon removal treatment or a silicon removal treatment can be selectively performed according to the residual condition of the elemental substance in the second intermediate. The step of removing the elemental carbon in the second intermediate includes: placing the second intermediate in an aerobic environment such as an air atmosphere or an oxygen atmosphere for calcination, wherein the heating rate is 0.5°C / min-10°C / min, specifically, the heating rate includes but is not limited to 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, and the calcination temperature is 800°C-2000°C, specifically, the calcination temperature is 1000°C. Including but not limited to 800℃, 900℃, 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, 1600℃, 1700℃, 1800℃, 1900℃, 2000℃, etc., and the calcination time is 0.5h-10h. Specifically, the calcination time includes but is not limited to 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc.; the step of removing elemental silicon in the second intermediate includes: placing the second intermediate in a strong alkali solution such as sodium hydroxide or a hydrofluoric acid solution for reaction.

[0053] The present invention also provides a porous silicon carbide material prepared by the method for preparing the porous silicon carbide material.

[0054] The porous silicon carbide material of the present invention has stable chemical properties, excellent corrosion resistance, oxidation resistance and high temperature resistance, and also has the advantages of excellent high-temperature strength. It has broad application prospects in many fields such as catalyst carriers, high-temperature gas filter adsorbents, molten metal filters, and thermal insulation or wave-absorbing materials.

[0055] Hereinafter, the porous silicon carbide material and the preparation method thereof will be further described through the following specific examples.

[0056] Example 1

[0057] Take 1 kg of biomass-based porous carbon, the specific surface area of the biomass-based porous carbon is 1200 m² / g, the pore volume is 0.5 cm³ / g, and the average pore diameter is 2.07 nm.

[0058] The biomass-based porous carbon was placed in a rotary kiln and replaced with nitrogen. The temperature was then raised to 500°C, and monosilane and nitrogen were introduced at a rate of 0.5 L / min and 3 L / min, respectively, for 360 minutes, yielding a first intermediate with a silane deposition rate of 20%.

[0059] The nitrogen was continued to flow for 30 min, the temperature was raised to 800°C and calcined for 5 h, and then the temperature was naturally lowered to obtain the second intermediate.

[0060] The second intermediate was placed in a muffle furnace, the temperature was adjusted to 800° C., and calcined in air for 5 hours to obtain a porous silicon carbide material.

[0061] Figure 1 SEM spectrum of biomass-based porous carbon, Figure 2 The SEM spectrum of the prepared porous silicon carbide material is compared with Figure 1 and Figure 2 It can be seen that the porous silicon carbide material basically retains the overall framework and structure of the porous carbon material, but adds some mesopores to the pore structure, which inevitably leads to the partial collapse of the microporous structure of the material, resulting in an increase in the pore volume and a decrease in the specific surface area of the material, but this ratio is fixed. In addition, Figure 3 is the XRD spectrum of the prepared porous silicon carbide material. Figure 3 It can be seen that there are obvious characteristic peaks of silicon carbide in the material. Figure 4 TEM spectrum of the prepared porous silicon carbide material. Figure 4 It can be clearly seen that there are a large number of micropores distributed in the material.

[0062] Example 2

[0063] Take 1 kg of resin-based porous carbon, the specific surface area of the resin-based porous carbon is 2000 m² / g, the pore volume is 0.8 cm³ / g, and the pore diameter is 2.41 nm.

[0064] The resin-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 450°C, and monosilane and nitrogen were introduced at a flow rate of 3 L / min and 15 L / min, respectively, for 300 minutes, yielding a first intermediate with a silane deposition rate of 55%.

[0065] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 1000°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0066] The second intermediate is placed in a 50% hydrofluoric acid-ethanol solution. The ethanol is high-purity ethanol with a concentration greater than 99.5%, and the volume ratio of the hydrofluoric acid solution to the ethanol solution is 1:5. The mixture is then stirred for 12 hours using a polytetrafluoroethylene stirrer to obtain a porous silicon carbide material.

[0067] Figure 5 The SEM spectrum of resin-based porous carbon, Figure 6 The SEM spectrum of the prepared porous silicon carbide material is compared with Figure 5 and Figure 6 It can be seen that after treatment, the overall structure of the material still maintains the porous carbon structure. As in Example 1, a large number of mesopores are added to the material, and the changes in pore volume and specific surface area are similar, which shows that this ratio change is not related to the type of porous carbon material. In addition, Figure 7 is the XRD spectrum of the prepared porous silicon carbide material. Figure 7 It can be seen that the material is a porous carbon structure. Figure 8 TEM spectrum of the prepared porous silicon carbide material. Figure 8 It can be seen that there are a large number of microporous structures in the material, confirming that the material is porous silicon carbide material.

[0068] Example 3

[0069] Take 1 kg of petroleum coke-based porous carbon, the specific surface area of the petroleum coke-based porous carbon is 2200 m² / g, the pore volume is 1.2 cm³ / g, and the pore diameter is 1.89 nm.

[0070] The petroleum coke-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 520°C, and monosilane gas and nitrogen were introduced at a flow rate of 3 L / min and 3 L / min, respectively, for 300 minutes, to produce a first intermediate with a silane deposition rate of 55%.

[0071] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 1100°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0072] The second intermediate was placed in a 49% hydrofluoric acid / ethanol solution, wherein the hydrofluoric acid was a 49% aqueous solution and the ethanol was a high-purity ethanol with a concentration greater than 99.5%. The volume ratio of the hydrofluoric acid solution to the ethanol solution was 1:5. The mixture was immersed and stirred with a polytetrafluoroethylene stirrer for 12 hours to obtain a porous silicon carbide material.

[0073] Example 4

[0074] Take 1 kg of biomass porous carbon, the specific surface area of the resin-based porous carbon is 2300 m² / g, the pore volume is 1.3 cm³ / g, and the pore diameter is 3.26 nm.

[0075] The resin-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 450°C, and monosilane and nitrogen were introduced at a flow rate of 3 L / min and 3 L / min, respectively, for 358 minutes, yielding a first intermediate with a silane deposition rate of 57%.

[0076] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 900°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0077] The second intermediate was placed in a 51% hydrofluoric acid / ethanol solution, wherein the hydrofluoric acid was a 51% aqueous solution and the ethanol was a high-purity ethanol with a concentration greater than 99.5%. The volume ratio of the hydrofluoric acid solution to the ethanol solution was 1:5. The mixture was immersed and stirred with a polytetrafluoroethylene stirrer for 14 hours to obtain a porous silicon carbide material.

[0078] Example 5

[0079] Take 1 kg of resin-based porous carbon, the specific surface area of the resin-based porous carbon is 2200 m² / g, the pore volume is 1.2 cm³ / g, and the pore diameter is 4.03 nm.

[0080] The resin-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 450°C, and monosilane and nitrogen were introduced at a flow rate of 3 L / min and 3 L / min, respectively, for 358 minutes, yielding a first intermediate with a silane deposition rate of 57%.

[0081] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 900°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0082] The second intermediate is placed in a hydrofluoric acid ethanol solution. The hydrofluoric acid is a 48% aqueous solution. The ethanol is a high-purity ethanol with a concentration greater than 99.5%. The volume ratio of the hydrofluoric acid solution to the ethanol solution is 1:5. The mixture is immersed and stirred with a polytetrafluoroethylene stirrer for 14 hours to obtain a porous silicon carbide material.

[0083] Example 6

[0084] Take 1 kg of resin-based porous carbon. The specific surface area of the resin-based porous carbon is 1500 m² / g, the pore volume is 0.61 cm³ / g, and the pore diameter is 2.11 nm.

[0085] The resin-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 500°C, and monosilane and nitrogen were introduced at a flow rate of 1 L / min and 3 L / min, respectively, for 360 minutes, yielding a first intermediate with a silane deposition rate of 31%.

[0086] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 800°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0087] The second intermediate was placed in a muffle furnace, the temperature was adjusted to 800° C., and the product was calcined in air for 5 hours to obtain a porous silicon carbide material.

[0088] Example 7

[0089] Take 1 kg of resin-based porous carbon, the specific surface area of the resin-based porous carbon is 1600 m² / g, the pore volume is 0.75 cm³ / g, and the pore diameter is 1.79 nm.

[0090] The resin-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 450°C, and monosilane and nitrogen were introduced at a flow rate of 1 L / min and 3 L / min, respectively, for 360 minutes, yielding a first intermediate with a silane deposition rate of 31%.

[0091] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 800°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0092] The second intermediate was placed in a muffle furnace, the temperature was adjusted to 800° C., and the product was calcined in air for 5 hours to obtain a porous silicon carbide material.

[0093] Example 8

[0094] Take 1 kg of biomass porous carbon, the specific surface area of the resin-based porous carbon is 1650 m² / g, the pore volume is 0.78 cm³ / g, and the pore diameter is 1.88 nm.

[0095] The resin-based porous carbon was placed in a rotary kiln and nitrogen was introduced to displace the atmosphere. The temperature was then raised to 450°C, and monosilane and nitrogen were introduced at a flow rate of 1 L / min and 3 L / min, respectively, for 360 minutes, yielding a first intermediate with a silane deposition rate of 31%.

[0096] After continuing to flow nitrogen for 30 minutes, the temperature was raised to 800°C and calcined for 5 hours, and then naturally cooled to obtain a second intermediate.

[0097] The second intermediate was placed in a muffle furnace, the temperature was adjusted to 800° C., and the product was calcined in air for 5 hours to obtain a porous silicon carbide material.

[0098] The specific surface area, pore volume and pore diameter of the porous carbon raw materials and the prepared porous silicon carbide in Examples 1 to 8 were tested and calculated, and the results are shown in Table 1 below.

[0099] Table 1

[0100]

[0101] As can be seen from Table 1, the preparation method of the present invention can effectively control the pore structure of the porous silicon carbide material, and porous carbon with different pore structures can be selected as a template to control the preparation of porous silicon carbide materials with different pore structures.

[0102] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a porous silicon carbide material, characterized in that: The steps include: Using porous carbon as a carrier, introducing a protective gas and a vapor-phase silicon source for chemical vapor deposition to obtain a first intermediate, wherein the porous carbon has a specific surface area of 1200m² / g-2300m² / g, a pore volume of 0.1cm³ / g-5.0cm³ / g, and a pore diameter of 1nm-1μm, and in the step of introducing the protective gas and the vapor-phase silicon source for chemical vapor deposition, the vapor-phase silicon source is selected from at least one of monosilane, ethylsilane, or silicon tetrachloride, the temperature is 500°C-600°C, and the flow ratio of the vapor-phase silicon source to the protective gas is 1:1-5:1; Continue to introduce protective gas and calcine the first intermediate to obtain a second intermediate, wherein the calcination temperature is 800° C.-1100° C. and the time is 5 h-7 h; The elemental carbon and / or elemental silicon in the second intermediate is removed to obtain a porous silicon carbide material.

2. The method for preparing the porous silicon carbide material according to claim 1, wherein: The porous carbon is selected from at least one of pitch-based porous carbon, biomass-based porous carbon, and resin-based porous carbon.

3. The method for preparing the porous silicon carbide material according to claim 1, wherein: In the step of introducing a protective gas and a gaseous silicon source to perform chemical vapor deposition, the protective gas is selected from at least one of nitrogen and argon.

4. The method for preparing the porous silicon carbide material according to claim 1, wherein: The step of removing elemental carbon from the second intermediate includes: placing the second intermediate in an oxygen environment for calcination, wherein the heating rate is 0.5°C / min-10°C / min, the calcination temperature is 800°C-2000°C, and the calcination time is 0.5h-10h.

5. The method for preparing the porous silicon carbide material according to claim 1, wherein: The step of removing elemental silicon from the second intermediate comprises: placing the second intermediate in a strong base or hydrofluoric acid solution for reaction.

6. A porous silicon carbide material prepared according to the method for preparing a porous silicon carbide material according to any one of claims 1 to 5.

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