A silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming and preparation method thereof

Abstract

The present invention relates to a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming and a preparation method. The preparation method of the silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming comprises the following steps: dissolving polycarbosilane and divinylbenzene in an organic solvent for reaction one, adding nickel acetylacetonate for reaction two after reaction one, and obtaining sample one; subjecting sample one to a hydrothermal reaction to obtain sample two; and drying, pyrolyzing, sintering, and calcining sample two under the protection of an inert gas. The preparation method of the silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming of the present invention uses nickel acetylacetonate to produce a cross-linking reaction with polycarbosilane, and before the polycarbosilane is cracked into silicon carbide, the nickel element is uniformly dispersed in the bulk phase, and due to the promotion effect of nickel on the crystallization of silicon carbide, after calcination under an inert gas atmosphere, an obvious 3C-SiC phase is formed.

Description

Technical Field

[0001] The invention belongs to a preparation process for preparing synthesis gas by reforming methane and carbon dioxide, and specifically relates to a silicon carbide-supported nickel-based catalyst for methane and carbon dioxide reforming and a preparation method thereof. Background Art

[0002] The extensive use of fossil fuels has led to the greenhouse effect, with carbon dioxide and methane being the top two culprits. Methane dry reforming uses these two greenhouse gases to react to generate synthesis gas, which can be directly used for Fischer-Tropsch synthesis, and has significant industrial environmental significance. However, methane dry reforming has serious sintering and carbon deposition problems, and there are roughly three types of solutions: physical constraints, metal-support interactions, and bimetallic (multimetallic) catalysts.

[0003] The excellent physical and chemical properties of silicon carbide make it a potential catalyst carrier. It has been used as a carrier for synthesis gas reactions and has shown excellent anti-sintering and anti-carbon deposition properties. However, due to the limited specific surface area of ​​traditional silicon carbide materials, large specific surface materials such as Al2O3 or zeolite are usually applied and covered on the surface of silicon carbide, and then the active material is loaded. This makes it difficult for the active material to come into direct contact with silicon carbide, which will undoubtedly limit the performance of silicon carbide.

[0004] Polymer-derived ceramic technology is an important method for preparing large-scale SiC. In-situ formation of metal nickel nanoparticles in the PDC matrix is ​​a promising method for preparing heterogeneous catalysts for methane dry reforming. This method can evenly disperse the active material in the carrier. However, due to insufficient calcination temperature and other reasons, crystalline silicon carbide was not formed in previous work. Silicon carbide only existed in an amorphous form, and the catalyst metal after calcination existed only in an oxidized state, and did not really interact with the silicon carbide as a metal carrier. Summary of the invention

[0005] The purpose of the present invention is to provide a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming, a preparation method and an application thereof, wherein the silicon carbide-supported nickel-based catalyst has stronger resistance to carbon deposition and sintering.

[0006] In order to achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming, comprising the following steps:

[0007] 1) dissolving polycarbosilane and divinylbenzene in an organic solvent to carry out reaction 1, and after reaction 1 is completed, adding nickel acetylacetonate to carry out reaction 2 to obtain sample 1;

[0008] 2) subjecting sample 1 to a hydrothermal reaction to obtain sample 2;

[0009] 3) Sample 2 was dried, pyrolyzed, sintered and calcined under the protection of inert gas.

[0010] Furthermore, in step 1), the reaction temperature of reaction 1 is 60-80°C, the temperature of reaction 2 is 100-120°C, and the reaction time of reaction 2 is 20-40 min.

[0011] Furthermore, in the hydrothermal reaction in step 2), the preheating temperature and time are: 130-150°C for 1-3h, 150-170°C for 1-3h, 170-190°C for 1-3h, and 190-210°C for 3-5h.

[0012] Furthermore, the drying temperature in step 3) is 150-250 °C, and the drying time is 24-72 h; the pyrolysis temperature in step 3) is 800-1000 °C, maintained for 1-3 h, and the heating rate is 0.5-1.5 °C per hour; then cooled to room temperature, and the cooling rate is 1-10 °C per minute; the sintering temperature in step 3) is 800-1400 °C, maintained for 1-3 h, and then cooled to room temperature, and the heating rate during sintering is 5-15 °C per minute, and the cooling rate is 10-30 °C per minute; the calcination temperature is 700-900 °C, maintained for 1-3 h.

[0013] Furthermore, the organic solvent in step 1) is decalin.

[0014] Furthermore, in the step 1), the amount of organic solvent added per gram of polycarbosilane is 2 mL, the amount of divinylbenzene added per gram of polycarbosilane is 2 / 3 mL; and the mass ratio of nickel acetylacetonate to polycarbosilane is 1:3-3.

[0015] Furthermore, the inert gas in the above step 3) is one of nitrogen, argon or helium.

[0016] A silicon carbide-supported nickel-based catalyst for methane and carbon dioxide reforming is obtained by adopting the above-mentioned method for preparing the silicon carbide-supported nickel-based catalyst for methane and carbon dioxide reforming.

[0017] Beneficial Effects

[0018] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming and the preparation method of the present invention use nickel acetylacetonate and polycarbosilane to produce a cross-linking reaction, and before the polycarbosilane is cracked into silicon carbide, the nickel element is uniformly dispersed in the bulk phase, and due to the promotion effect of nickel on the crystallization of silicon carbide, after calcination in an inert gas atmosphere at about 1400°C, an obvious 3C-SiC phase is formed.

[0019] The silicon carbide-loaded nickel-based catalyst for methane carbon dioxide reforming and the preparation method of the present invention adopt high-temperature calcination, and the nickel element shows a change from NiO to Ni2Si. Experimental and characterization results show that in the methane dry reforming reaction, under the same nickel content, Ni2Si shows higher conversion rate and stability than NiO, and has stronger resistance to carbon deposition and sintering.

[0020] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming and the preparation method of the present invention have good thermal conductivity and can inhibit the generation of hot spots on the catalyst surface. Silicon carbide has high mechanical strength and will not significantly shrink or collapse the catalyst during long-term reaction at high temperature, thus ensuring the structural integrity of the catalyst.

[0021] The silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming and the preparation method of the present invention synthesizes silicon carbide with a large specific surface area by means of a polymer-derived ceramic technology synthesis method, and simultaneously generates uniformly distributed crystalline nickel nanoparticles in situ in an amorphous SiC(O) matrix, thereby ensuring that the nickel in the subsequently prepared catalyst can be uniformly distributed in the SiC crystal.

[0022] The temperature of the reforming reaction is generally 700-800°C, which is greater than 0.3 times the melting point of the nano-metal of the nickel element and is equivalent to 0.5 times the melting point of the nano-metal of the nickel element. The nano-metal on the catalyst surface will migrate and flow, causing the catalyst to be deactivated due to sintering. Through the "dissolution-recrystallization" process in the loading process of the present invention, the metal and the carrier have a strong interaction, and the Ni atoms are effectively confined in the SiC lattice to prevent the sintering of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 N2 adsorption-desorption curves of the catalysts generated in Examples 1, 2 and 3 of the present invention;

[0024] Figure 2 XRD images of catalysts generated in Example 1, Example 2 and Example 3 of the present invention;

[0025] Figure 3 This is a graph showing the catalytic performance test results of methane carbon dioxide reforming in Test Example 1 of the present invention;

[0026] Figure 4 This is a graph showing the catalytic performance test results of methane carbon dioxide reforming in Test Example 2 of the present invention;

[0027] Figure 5 This is a graph showing the catalytic performance test results of methane carbon dioxide reforming in Test Example 3 of the present invention;

[0028] Figure 6This is a graph showing the 5 h catalytic stability test results of methane reforming in Test Example 4 of the present invention;

[0029] Figure 7 This is a graph showing the 5 h catalytic stability test results of carbon dioxide reforming in Test Example 4 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the embodiments of the present invention and the accompanying drawings.

[0031] Example 1

[0032] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 60 ° C to dissolve, and 2 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 100 ° C. After 20 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is hydrothermally placed in an oven at a preset temperature. The hydrothermal reaction temperature is 140 ° C for 2 h, 160 ° C for 2 h, 180 ° C for 2 h, and 200 ° C for 4 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane and nickel acetylacetonate undergo cross-linking reaction at the same time, ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 200 °C for 72 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 800 °C at a rate of 1 °C per minute, maintained for 2 h, and then cooled to room temperature at a rate of 5 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 800 °C for 2 h. The heating rate of the sintering was 10 °C per minute and the cooling rate was 20 °C per minute. The sintered sample 2 was calcined at 800 °C in a muffle furnace for 2 h to obtain a nickel-based silicon carbide catalyst Ni@SiC-800 °C.

[0033] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-800°C.

[0034] Example 2

[0035] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 60 ° C to dissolve, and 2 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 100 ° C. After 20 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is hydrothermally placed in an oven at a preset temperature. The hydrothermal reaction temperature is 140 ° C for 2 h, 160 ° C for 2 h, 180 ° C for 2 h, and 200 ° C for 4 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane and nickel acetylacetonate undergo cross-linking reaction at the same time, ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 200 °C for 72 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 800 °C at a rate of 1 °C per minute, maintained for 2 h, and then cooled to room temperature at a rate of 5 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 1100 °C for 2 h. The heating rate of the sintering was 10 °C per minute and the cooling rate was 20 °C per minute. The sintered sample 2 was calcined at 800 °C in a muffle furnace for 2 h to obtain a nickel-based silicon carbide catalyst Ni@SiC-1100 °C.

[0036] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-1100°C.

[0037] Example 3

[0038] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 60 ° C to dissolve, and 2 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 100 ° C. After 20 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is hydrothermally placed in an oven at a preset temperature. The hydrothermal reaction temperature is 140 ° C for 2 h, 160 ° C for 2 h, 180 ° C for 2 h, and 200 ° C for 4 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane and nickel acetylacetonate undergo cross-linking reaction at the same time, ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 200 °C for 72 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 800 °C at a rate of 1 °C per minute, maintained for 2 h, and then cooled to room temperature at a rate of 5 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 1400 °C for 2 h. The heating rate of the sintering was 10 °C per minute and the cooling rate was 20 °C per minute. The sintered sample 2 was calcined at 800 °C in a muffle furnace for 2 h to obtain a nickel-based silicon carbide catalyst Ni@SiC-1400 °C.

[0039] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-1400°C.

[0040] Example 4

[0041] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 60 ° C to dissolve, 1 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 100 ° C. After 20 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is hydrothermally placed in an oven at a preset temperature. The hydrothermal reaction temperature is 140 ° C for 2 h, 160 ° C for 2 h, 180 ° C for 2 h, and 200 ° C for 4 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane simultaneously undergoes a cross-linking reaction with nickel acetylacetonate, thereby ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 200 °C for 72 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 800 °C at a rate of 1 °C per minute, maintained for 2 h, and then cooled to room temperature at a rate of 5 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 1400 °C for 2 h. The heating rate of the sintering was 10 °C per minute and the cooling rate was 20 °C per minute. The sintered sample 2 was calcined at 800 °C in a muffle furnace for 2 h to obtain the nickel-based silicon carbide catalyst Ni@SiC-1400 °C-1.

[0042] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-1400℃-1.

[0043] Example 5

[0044] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 60 ° C to dissolve, 3 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 100 ° C. After 20 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is hydrothermally placed in an oven at a preset temperature. The hydrothermal reaction temperature is 140 ° C for 2 h, 160 ° C for 2 h, 180 ° C for 2 h, and 200 ° C for 4 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane and nickel acetylacetonate undergo cross-linking reaction at the same time, ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 200 °C for 72 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 800 °C at a rate of 1 °C per minute, maintained for 2 h, and then cooled to room temperature at a rate of 5 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 1400 °C for 2 h. The heating rate of the sintering was 10 °C per minute and the cooling rate was 20 °C per minute. The sintered sample 2 was calcined at 800 °C in a muffle furnace for 2 h to obtain the nickel-based silicon carbide catalyst Ni@SiC-1400 °C-3.

[0045] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-1400℃-3.

[0046] Example 6

[0047] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 70 ° C to dissolve, and 2 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 110 ° C. After 30 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is placed in an oven at a preset temperature for hydrothermal. The hydrothermal reaction temperature is 130 ° C for 1 h, 150 ° C for 1 h, 170 ° C for 1 h, and 190 ° C for 3 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane and nickel acetylacetonate undergo cross-linking reaction at the same time, ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 150 °C for 24 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 900 °C at a rate of 0.5 °C per minute, maintained for 1 h, and then cooled to room temperature at a cooling rate of 1 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 800 °C for 1 h. The heating rate of the sintering was 5 °C per minute and the cooling rate was 10 °C per minute. The sintered sample 2 was calcined at 700 °C in a muffle furnace for 1 h to obtain a nickel-based silicon carbide catalyst Ni@SiC-a.

[0048] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-a.

[0049] Example 7

[0050] The preparation method of silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming of the present embodiment comprises the following steps: at room temperature, 3 g polycarbosilane, 6 mL decalin and 2 mL p-divinylbenzene are weighed and mixed, heated and stirred at 80 ° C to dissolve, 2 g nickel acetylacetonate is added after complete dissolution, and the temperature is maintained at 120 ° C. After 40 min, sample 1 is obtained, and sample 1 is a dark green transparent viscous solution. Sample 1 is poured into a polytetrafluoroethylene mold, placed in an autoclave, and the autoclave is hydrothermally placed in an oven at a preset temperature. The hydrothermal reaction temperature is 150 ° C for 3 h, 170 ° C for 3 h, 190 ° C for 1 h, and 210 ° C for 5 h. During the hydrothermal reaction, polycarbosilane and decalin undergo hydrosilylation reaction. While the hydrosilylation reaction occurs, polycarbosilane simultaneously undergoes cross-linking reaction with nickel acetylacetonate, thereby ensuring the uniform distribution of the nickel element of the subsequent catalyst. After hydrothermal crosslinking, sample 2 was obtained. Sample 2 was dried at 250 °C for 48 h under the protection of nitrogen. Under the protection of argon, the dried sample 2 was pyrolyzed in a tube furnace. The pyrolysis was first heated to 1000 °C at a rate of 1.5 °C per minute, maintained for 3 h, and then cooled to room temperature at a rate of 10 °C per minute. Subsequently, the pyrolyzed sample 2 was placed in a graphite furnace for sintering at 800 °C for 3 h, with a heating rate of 15 °C per minute and a cooling rate of 30 °C per minute. The sintered sample 2 was calcined at 900 °C in a muffle furnace for 3 h to obtain a nickel-based silicon carbide catalyst Ni@SiC-b.

[0051] The silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming in this embodiment is Ni@SiC-b.

[0052] Comparative Example 1

[0053] At room temperature, 3 g of nano silicon carbide powder was weighed, 1.59 g of nickel nitrate hexahydrate was dissolved in 3 mL of ethanol, and the mixture was slowly added dropwise to the nano silicon carbide powder to mix well and allowed to stand for 24 h to obtain sample 1. The sample 1 after standing was placed in an oven at a preset temperature of 100 °C for drying and calcined in a muffle furnace at 800 °C for 2 h to obtain a catalyst Ni / SiC-Impergnation having the same Ni / Si ratio as that of Examples 1 to 3.

[0054] Test Example 1

[0055] 0.1 g of Ni@SiC-1400℃, Ni@SiC-1400℃-1 and Ni@SiC-1400℃-3 synthesized in Example 3, Example 4 and Example 5 were respectively weighed and loaded into a reaction tube, and methane, carbon dioxide and argon were introduced at 1 atm for reaction. The reaction temperature was 800℃ and the gas hourly velocity GHSV was 56000 mL·g -1 ·h -1 , the volume ratio of CH4:CO2:Ar is 1:1:4. The catalytic performance of Ni@SiC-1400℃, Ni@SiC-1400℃-1 and Ni@SiC-1400℃-3 synthesized in Examples 3, 4 and 5 was tested at 800℃. The results are shown in Figure 3 As shown. Figure 3 It can be seen that at a reaction temperature of 800 ℃, the initial methane and carbon dioxide conversion rates of the Ni@SiC-1400℃ catalyst were 91.50% and 92.82%, respectively, showing a higher catalytic activity. The initial methane and carbon dioxide conversion rates of the Ni@SiC-1400℃-1 catalyst were only 79.68% and 81.31%. The initial methane conversion rate of the Ni@SiC-1400℃-3 catalyst was 90.89%, which was comparable to the Ni@SiC-1400℃ catalyst, but the initial carbon dioxide conversion rate dropped significantly to only 86.26%. It can be seen that the maximum conversion rate was reached when the ratio of nickel acetylacetonate to polycarbosilane was 2:3, and the catalytic performance did not improve when the amount of nickel acetylacetonate was further increased.

[0056] Test Example 2

[0057] 0.1 g of Ni@SiC-800°C, Ni@SiC-1100°C, Ni@SiC-1400°C and Ni / SiC-Impregnation synthesized in Example 1, Example 2, Example 3 and Comparative Example 1 were weighed and loaded into a reaction tube, and methane, carbon dioxide and argon were introduced at 1 atm for reaction. The reaction temperature was 800°C and the gas hourly velocity GHSV was 56000 mL·g -1 ·h -1 , the volume ratio of CH4:CO2:Ar is 1:1:4. The catalytic performance of Ni@SiC-800℃, Ni@SiC-1100℃, Ni@SiC-1400℃ and Ni / SiC-Impregnation synthesized in Example 1, Example 2, Example 3 and Comparative Example 1 at 800℃ was tested. The results are as follows Figure 4 As shown. Figure 4It can be seen that at a reaction temperature of 800 ℃, the initial methane and carbon dioxide conversion rates of the Ni / SiC-Impregnation catalyst were 81.78% and 78.26%, respectively. After the cross-linked catalyst was calcined at 1400 ℃, the Ni@SiC-1400 ℃ catalyst showed higher catalytic activity, with initial methane and carbon dioxide conversion rates of 91.50% and 92.82%, respectively. The two catalysts have the same Ni / Si ratio.

[0058] Test Example 3

[0059] 0.1 g of Ni@SiC-a and Ni@SiC-b synthesized in Example 6 and Example 7 were weighed and loaded into a reaction tube, and methane, carbon dioxide and argon were introduced at 1 atm for reaction. The reaction temperature was 800 °C and the gas hourly velocity GHSV was 56000 mL·g -1 ·h -1 , the volume ratio of CH4:CO2:Ar is 1:1:4. The catalytic performance of Ni@SiC-a and Ni@SiC-b synthesized in Example 6 and Example 7 was tested at 800 °C. The results are shown in Figure 5 As shown. Figure 5 It can be seen that after changing the reaction parameters, the catalyst performance changed. At a reaction temperature of 800 °C, the initial methane and carbon dioxide conversion rates of the Ni@SiC-a catalyst were 84.39% and 82.64%, respectively, and the initial methane and carbon dioxide conversion rates of the Ni@SiC-b catalyst were 90.89% and 86.26%, respectively, both higher than the catalyst Ni / SiC-Imregnation in Comparative Example 1.

[0060] Test Example 4

[0061] 0.1 g of Ni@SiC-1400℃ and Ni / SiC-Impregnation synthesized in Example 3 and Comparative Example 1 were weighed and loaded into a reaction tube, and methane, carbon dioxide and argon were introduced at 1 atm for reaction. The reaction temperature was 800℃ and the gas hourly velocity GHSV was 56000 mL·g -1 ·h -1 , the volume ratio of CH4:CO2:Ar is 1:1:4. The catalytic stability of Ni@SiC-1400℃ and Ni / SiC-Impregnation synthesized in Example 3 and Comparative Example 1 was tested at 800℃ for 5 hours.

[0062] The results are as follows Figure 5 and Figure 6 As shown by Figure 5 and Figure 6It can be seen that at a reaction temperature of 800 °C, the methane and carbon dioxide conversion rates of the Ni / SiC-Impregnation catalyst decreased significantly after 5 h, while the conversion rate of the Ni@SiC-1400 °C catalyst remained basically unchanged after 5 h, which was attributed to the strong interaction between Ni and SiC, which improved the catalytic activity and resistance.

Claims

1. A method for preparing a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming, characterized in that: The following steps are involved: 1) dissolving polycarbosilane and divinylbenzene in an organic solvent to carry out reaction 1, and after the reaction 1 is completed, adding nickel acetylacetonate to carry out reaction 2 to obtain sample 1; 2) subjecting sample 1 to a hydrothermal reaction to obtain sample 2; 3) Sample 2 is dried under the protection of inert gas, then pyrolyzed under the protection of inert gas, then sintered under the protection of inert gas, and calcined in a muffle furnace; The reaction temperature of reaction 1 in step 1) is 60-80°C, the temperature of reaction 2 is 100-120°C, and the reaction time of reaction 2 is 20-40min; the preheating temperature and time of the hydrothermal reaction in step 2) are: 130-150°C for 1-3h, 150-170°C for 1-3h, 170-190°C for 1-3h, and 190-210°C for 3-5h; the drying temperature in step 3) is 150-250°C, and the drying time is 24-72h; In the step 3), the pyrolysis temperature is 800-1000°C, maintained for 1-3 hours, and the heating rate is 0.5-1.5°C per hour; then it is cooled to room temperature, and the cooling rate is 1-10°C per minute; the sintering temperature in the step 3) is 1400°C, maintained for 1-3 hours, and then cooled to room temperature. During sintering, the heating rate is 5-15°C per minute, and the cooling rate is 10-30°C per minute; the calcination temperature is 700-900°C, maintained for 1-3 hours; the mass ratio of polycarbosilane to nickel acetylacetonate is 3:

2.

2. The method for preparing a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming according to claim 1, characterized in that: The organic solvent in step 1) is decalin.

3. The method for preparing a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming according to claim 1, characterized in that: In the step 1), the amount of organic solvent added per gram of polycarbosilane is 2 mL, and the amount of divinylbenzene added per gram of polycarbosilane is 2 / 3 mL.

4. The method for preparing a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming according to claim 1, characterized in that: The method for preparing a silicon carbide-supported nickel-based catalyst for methane carbon dioxide reforming according to claim 1, characterized in that the inert gas in step 3) is one of nitrogen, argon or helium.

5. A silicon carbide supported nickel-based catalyst for methane carbon dioxide reforming, characterized in that: The catalyst is obtained by using the method for preparing the silicon carbide supported nickel-based catalyst for methane and carbon dioxide reforming as claimed in claim 1.

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