Nickel-samarium bimetal synergetic / MCM-41 molecular sieve catalyst as well as preparation method and application thereof

Abstract

The invention discloses a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst as well as a preparation method and application thereof. The catalyst comprises a carrier and active components loaded on the carrier, the carrier is an MCM-41 molecular sieve, and the active components are nickel and samarium. Compared with other nickel-based catalysts, the catalyst disclosed by the invention has the advantages that through the synergistic effect of nickel and samarium bimetals, the interaction between the active component and the carrier is enhanced, the dispersion degree of the active metal is improved, and the anti-sintering capability of the active metal is enhanced; and the surface of the catalyst has high oxygen vacancy concentration, so that the activation of CO2 is promoted, the number of active oxygen species on the surface of the catalyst is increased, and the removal of deposited carbon is promoted. Therefore, the catalyst has good sintering resistance and carbon deposition resistance and high catalytic stability, and meets the use requirements of industrial catalysts.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst and a preparation method and application thereof. Background Art

[0002] More than 30Gt of CO2 is released into the atmosphere every year, causing serious environmental problems such as global warming. At the same time, methane (CH4) is another major greenhouse gas. The unlimited release of methane caused by the release of natural gas in permafrost and shale gas development has further aggravated environmental problems. Therefore, it is crucial to take effective measures to transform and utilize these two greenhouse gases.

[0003] Dry reforming of CO2 with methane (DRM) was first widely studied in the early 20th century. In 1946, researchers first discovered that cobalt-based catalysts could promote the dry reforming reaction of CH4 with CO2, and pointed out that improving the stability of cobalt-based catalysts was one of the important factors for achieving efficient DRM. In 1958, other studies further showed that Co / La2O3-SiO2 catalysts supported on SiO2 carriers with Co and La2O3 as active components showed high catalytic activity and stability in the temperature range of 1073K to 1173K. Since then, in the optimization research of DRM catalysts, it was found that compared with traditional precious metal catalysts (such as Pt, Rh), economical and efficient Ni-based and Co-based catalysts can show excellent methane activation performance and anti-carbon deposition ability at higher temperatures, thus becoming a research hotspot in this field.

[0004] However, a large number of research results show that in the DRM reaction, Ni-based catalysts still face two common problems: sintering and carbon deposition, which lead to catalyst deactivation and poor stability. Therefore, how to design catalysts to improve the carbon deposition and sintering resistance of Ni-based catalysts has become the key to the further industrial application of methane dry reforming and the large-scale production of synthesis gas. Summary of the invention

[0005] The main purpose of the present invention is to provide a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with good anti-sintering, anti-carbon deposition capabilities and catalytic stability, as well as a preparation method and application thereof.

[0006] To achieve the above object, the present invention provides a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst, comprising a carrier and an active component loaded on the carrier, wherein the carrier is the MCM-41 molecular sieve, and the active components are nickel and samarium.

[0007] Furthermore, the nickel content is 5-20wt%, the samarium content is 1-20wt%, and the balance is MCM-41 molecular sieve.

[0008] The present invention also provides a method for preparing the above-mentioned nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst, comprising the following steps:

[0009] (1) dissolving nickel and samarium precursor salts in deionized water, adding ammonia water to obtain an alkaline nickel-samarium ammine complex solution, adding MCM-41 molecular sieves to the alkaline nickel-samarium ammine complex solution, and then heating and stirring the solution under closed conditions, and then heating and evaporating the solution until the pH value reaches neutral, to obtain a reaction mixture;

[0010] (2) The reaction mixture is centrifuged, the obtained solid is dried, ground into powder, and finally calcined in an air atmosphere to obtain the nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst.

[0011] Furthermore, in step (1), the amount of ammonia water added is such that the pH value reaches 10 to 12, and the stirring treatment is carried out at room temperature for 8 to 12 hours.

[0012] Furthermore, in step (1), the heating and evaporation temperature is 60 to 90°C.

[0013] Furthermore, in step (2), the drying treatment conditions are a temperature of 80 to 110° C. and a time of 8 to 12 hours.

[0014] Furthermore, in step (2), the specific process of the calcination treatment is: heating the temperature to 550-700°C at a heating rate of 1-5°C / min, and then calcining at this temperature for 2-6 hours.

[0015] The present invention also provides the use of the above-mentioned nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst in catalyzing methane dry reforming to produce synthesis gas.

[0016] The present invention also provides a method for catalytic methane dry reforming to produce synthesis gas, comprising the following steps: reducing the above-mentioned catalyst in a 10 vol% H2 / N2 atmosphere at a temperature of 550-750°C for 2-4 hours, then mixing it with inert silicon carbide, and catalytically conducting a methane dry reforming reaction to produce synthesis gas in a reactor.

[0017] Furthermore, the catalyst and inert silicon carbide are mixed by solid phase grinding at a mass ratio of 1:2-5 for 10-15 minutes, and the reaction conditions are: the molar ratio of CH4 to CO2 in the reaction feed is 1-2, the gas feed space velocity is 40000-120000 mL·h-1·gcat-1, the catalyst dosage is 0.05-0.5 g, and the reaction temperature is 550-850° C. In the process of implementing the present invention, the inventors found that under this reaction condition, the above catalyst exhibits a high methane / carbon dioxide conversion rate of more than 80% in the 800h catalytic methane dry reforming reaction to produce synthesis gas, and the H2 / CO ratio in the synthesis gas is 0.8-1.2.

[0018] MCM-41 molecular sieve has a two-dimensional hexagonal structure and a large specific surface area. Its unique structural characteristics help the distribution of active metals to form more active sites.

[0019] Compared with nickel / MCM-41 molecular sieve, the synergy of nickel-samarium bimetallic not only improves the anti-sintering ability of active metals through the interaction between active components and carriers, but also the high oxygen vacancy concentration is beneficial to promote the activation of CO2 and increase the number of active oxygen species on the catalyst surface, thereby promoting the removal of carbon deposits.

[0020] Samarium, as a lanthanide metal, has good redox properties and high oxygen mobility. The present invention prepares a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst, which is beneficial to promoting the removal of carbon on the catalyst surface, while improving the strong interaction between the metal and the carrier and realizing the anchoring of the active metal nickel.

[0021] The beneficial effects of the present invention are embodied in:

[0022] 1. The catalyst of the present invention has the characteristics of green economy and high structural stability. When used in the catalytic CH4-CO2 reforming reaction to produce synthesis gas, it exhibits a high methane / carbon dioxide conversion rate of more than 80% in the 800h catalytic methane dry reforming reaction to produce synthesis gas, and the H2 / CO ratio in the synthesis gas is 0.8 to 1.2.

[0023] 2. The catalyst of the present invention uses nickel samarium as the active metal, which can ensure that the catalyst has high activity in cracking CH bonds of methane. The use of the MCM-41 molecular sieve carrier saves the cost of catalyst preparation and promotes the dispersion of active components.

[0024] 3. Compared with other nickel-based catalysts, the catalyst of the present invention enhances the interaction between the active component and the carrier through the synergistic effect of the nickel-samarium bimetallic, improves the dispersion of the active metal, and enhances the anti-sintering ability of the active metal; and the catalyst surface has a high oxygen vacancy concentration, which is conducive to promoting the activation of CO2 and increasing the number of active oxygen species on the catalyst surface, thereby promoting the removal of carbon deposits. Therefore, the catalyst has good anti-sintering, anti-carbon deposition and high catalytic stability, meeting the requirements for the use of industrial catalysts.

[0025] 4. The catalyst of the present invention is used in the catalytic methane dry reforming reaction to produce synthesis gas, which can significantly enhance the catalytic adsorption and activation ability of CH4 and CO2 molecules, has high CH4 and CO2 conversion rates, and shows good prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The XRD patterns of the catalysts prepared in Example 2 and Comparative Example 1;

[0027] Figure 2 The catalyst prepared in Example 2 and the MCM-41 molecular sieve are N2 adsorption-desorption isotherms;

[0028] Figure 3 The pore size distribution diagram of the catalyst prepared in Example 2 and the MCM-41 molecular sieve;

[0029] Figure 4 TEM images of the catalysts prepared in Example 2 and Comparative Example 1;

[0030] Figure 5 The EPR diagrams of the catalysts prepared in Example 2 and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0031] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0032] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods; unless otherwise specified, the methods used in the examples of the present invention are methods known to those skilled in the art.

[0033] MCM-41 molecular sieve was purchased from Aladdin Biochemical Technology Co., Ltd., with a pore size of 2.5 nm, a particle size of 1-2 μm, and a specific surface area (m 2 / g):600-800.

[0034] Inert silicon carbide was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. with a particle size of 200 mesh.

[0035] Example 1

[0036] Preparation of Ni-Samarium Bimetallic Synergistic / MCM-41 Molecular Sieve Catalyst

[0037] The nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst prepared in this embodiment has an active component nickel content of 5wt%, a samarium content of 3wt%, and the remaining component is an MCM-41 molecular sieve carrier. The preparation method is as follows:

[0038] (1) 0.2692 g of nickel nitrate hexahydrate and 0.0963 g of samarium nitrate hexahydrate were weighed and dissolved in 75 mL of deionized water. After being fully stirred to dissolve to form a uniform solution, 28% ammonia water was added to adjust the pH to 10, and then 1 g of MCM-41 molecular sieve carrier was added. The mixture was sealed with plastic wrap, stirred at 300 r / min at room temperature for 8 h, and then heated at 90° C. for evaporation (ammonia and water were evaporated) until the solution was neutral to obtain a reaction mixture;

[0039] (2) The reaction mixture was washed by centrifugation, and the obtained solid was dried at 80°C for 12 h, then ground into powder, and finally placed in an air atmosphere of 100 mL / min and heated to 600°C at a rate of 1°C / min and calcined at a constant temperature for 6 h. After naturally cooling to room temperature, a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with a nickel content of 5 wt% and a samarium content of 3 wt% was obtained, which was recorded as 5Ni3Sm / MCM-41.

[0040] Example 2

[0041] Preparation of Ni-Samarium Bimetallic Synergistic / MCM-41 Molecular Sieve Catalyst

[0042] The nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst prepared in this embodiment has an active component nickel content of 10wt%, a samarium content of 1wt%, and the remaining component is an MCM-41 molecular sieve carrier. The preparation method is as follows:

[0043] (1) Weigh 0.5548 g of nickel nitrate hexahydrate and 0.0331 g of samarium nitrate hexahydrate and dissolve them in 75 mL of deionized water. After fully stirring and dissolving to form a uniform solution, add 28% ammonia water to adjust the pH to 12, then add 1 g of MCM-41 molecular sieve carrier, seal with plastic wrap, stir at room temperature at a speed of 300 r / min for 12 h, and then heat and evaporate at 80° C. until the solution is neutral to obtain a reaction mixture;

[0044] (2) The reaction mixture was centrifuged and washed, and the obtained solid was dried at 105°C for 12 h, then ground into powder, and finally placed in an air atmosphere of 100 mL / min and heated to 550°C at a heating rate of 4°C / min and calcined at a constant temperature for 5 h, and naturally cooled to room temperature to obtain a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with a nickel content of 10 wt% and a samarium content of 1 wt%, denoted as 10Ni1Sm / MCM-41.

[0045] Example 3

[0046] Preparation of Ni-Samarium Bimetallic Synergistic / MCM-41 Molecular Sieve Catalyst

[0047] The nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst prepared in this embodiment has an active component nickel content of 12wt%, a samarium content of 20wt%, and the remaining component is an MCM-41 molecular sieve carrier. The preparation method is as follows:

[0048] (1) Weigh 0.8744 g of nickel nitrate hexahydrate and 0.8694 g of samarium nitrate hexahydrate and dissolve them in 75 mL of deionized water. After fully stirring and dissolving to form a uniform solution, add 28% ammonia water to adjust the pH to 11, then add 1 g of MCM-41 molecular sieve carrier, seal with plastic wrap, stir at room temperature at a speed of 300 r / min for 9 h, and then heat and evaporate at 70° C. until the solution is neutral to obtain a reaction mixture;

[0049] (2) The reaction mixture was centrifuged and washed, and the obtained solid was dried at 110°C for 8 h, then ground into powder, and finally placed in an air atmosphere of 100 mL / min and heated to 650°C at a rate of 2°C / min and calcined at a constant temperature for 3 h, and naturally cooled to room temperature to obtain a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with a nickel content of 12 wt% and a samarium content of 20 wt%, recorded as 12Ni20Sm / MCM-41.

[0050] Example 4

[0051] Preparation of Ni-Samarium Bimetallic Synergistic / MCM-41 Molecular Sieve Catalyst

[0052] The nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst prepared in this embodiment has an active component nickel content of 10wt%, a samarium content of 1wt%, and the remaining component is an MCM-41 molecular sieve carrier. The preparation method is as follows:

[0053] (1) Weigh 0.9908 g of nickel nitrate hexahydrate and 0.3941 g of samarium nitrate hexahydrate and dissolve them in 75 mL of deionized water. After fully stirring and dissolving to form a uniform solution, add 28% ammonia water to adjust the pH to 10, then add 1 g of MCM-41 molecular sieve carrier, seal with plastic wrap, stir at room temperature at a speed of 300 r / min for 10 h, and then heat and evaporate at 60° C. until the solution is neutral to obtain a reaction mixture;

[0054] (2) The reaction mixture was centrifuged and washed, and the obtained solid was dried at 90°C for 11 hours, then ground into powder, and finally placed in an air atmosphere of 100 mL / min and heated to 600°C at a rate of 5°C / min and calcined at a constant temperature for 4 hours, and naturally cooled to room temperature to obtain a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with a nickel content of 10 wt% and a samarium content of 1 wt%, recorded as 15Ni10Sm / MCM-41.

[0055] Example 5

[0056] Preparation of Ni-Samarium Bimetallic Synergistic / MCM-41 Molecular Sieve Catalyst

[0057] The nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst prepared in this embodiment has an active component nickel content of 20wt%, a samarium content of 5wt%, and the remaining component is an MCM-41 molecular sieve carrier. The preparation method is as follows:

[0058] (1) 1.3212 g of nickel nitrate hexahydrate and 0.1971 g of samarium nitrate hexahydrate were weighed and dissolved in 75 mL of deionized water. After being fully stirred to dissolve to form a uniform solution, 28% ammonia water was added to adjust the pH to 12, and then 1 g of MCM-41 molecular sieve carrier was added. The mixture was sealed with plastic wrap, stirred at 300 r / min at room temperature for 11 h, and then heated and evaporated at 80° C. until the solution was neutral to obtain a reaction mixture;

[0059] (2) The reaction mixture was centrifuged and washed, and the obtained solid was dried at 100°C for 10 h, then ground into powder, and finally placed in an air atmosphere of 100 mL / min and heated to 700°C at a rate of 3°C / min and calcined at a constant temperature for 2 h, and naturally cooled to room temperature to obtain a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with a nickel content of 10 wt% and a samarium content of 1 wt%, recorded as 20Ni5Sm / MCM-41.

[0060] Comparative Example 1

[0061] Preparation of comparative catalysts

[0062] In this comparative example, the catalyst was prepared in the same manner as in Example 2, except that the addition of samarium nitrate hexahydrate was omitted and the amount of nickel nitrate hexahydrate was adjusted to 0.5504 g, and finally a MCM-41 molecular sieve-supported nickel catalyst with a nickel content of 10 wt% was obtained, which was recorded as 10Ni / MCM-41.

[0063] Comparative Example 2

[0064] Preparation of comparative catalysts

[0065] In this comparative example, the catalyst was prepared in the same manner as in Example 3, except that the addition of nickel nitrate hexahydrate was omitted and the amount of samarium nitrate hexahydrate was adjusted to 0.7389 g. Finally, a MCM-41 molecular sieve-loaded samarium catalyst having a samarium content of 20 wt% was obtained, which was recorded as 20Sm / MCM-41.

[0066] Comparative Example 3

[0067] Preparation of comparative catalysts

[0068] In this comparative example, the catalyst was prepared according to the method of Example 2, except that samarium nitrate hexahydrate was replaced by zirconium nitrate pentahydrate, and the amount of zirconium nitrate pentahydrate was 0.0471 g. Finally, a nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst with a nickel content of 10 wt% and a zirconium content of 1 wt% was obtained, which was recorded as 10Ni1Zr / MCM-41.

[0069] Comparative Example 4

[0070] Preparation of comparative catalysts

[0071] In this comparative example, the catalyst was prepared according to the method of Example 2, except that the carrier was replaced with an equal amount of SBA-15 molecular sieve, and finally a nickel-samarium bimetallic synergistic / SBA-15 molecular sieve catalyst with a nickel content of 10wt% and a samarium content of 1wt% was obtained, which was recorded as 10Ni1Sm / SBA-15.

[0072] Experimental Example 1

[0073] Determination of the physicochemical properties of Ni-Samarium bimetallic synergistic / MCM-41 molecular sieve catalyst

[0074] The structure of the catalysts prepared by the carrier MCM-41 molecular sieve and the examples and comparative examples was analyzed. Figures 1 to 5 shown.

[0075] See also Figure 1 , XRD spectrum of metal-supported MCM-41 molecular sieve catalyst Figure 2Two sharp peaks were detected at θ=37.3° and 43.2°, corresponding to (111) and (200) of NiO phase. Compared with the XRD peaks without adding samarium metal, they are sharper, proving that the addition of samarium can make the dispersion of nickel metal more uniform when using MCM-41 molecular sieve as carrier.

[0076] See also Figure 2 According to the IUPAC classification, compared with MCM-41 molecular sieve, the Ni-Sm bimetallic / MCM-41 molecular sieve exhibits a IV isotherm, accompanied by an H3 type hysteresis loop. This indicates that the prepared Ni-Sm bimetallic / MCM-41 molecular sieve catalyst has an expanded internal pore size after high-temperature calcination, forming an obvious mesoporous structure, which is conducive to the entry of loaded metals.

[0077] See also Figure 3 , the MCM-41 molecular sieve is concentrated at 2.5nm, while the pore size distribution at 0.5nm and 5.8nm after metal loading and calcination further proves the existence of this microporous-mesoporous composite pore structure, which is beneficial to promote the dispersion of active metals on the surface of the carrier and promote reaction mass transfer.

[0078] See also Figure 4 From the TEM image, it can be observed that the active metals are dispersed on the surface of the MCM-41 molecular sieve carrier. After the addition of samarium, the particle size is smaller and the dispersion is more uniform, which is conducive to exposing more active centers and promoting the adsorption and activation of methane molecules during the catalytic methane dry reforming reaction to produce synthesis gas.

[0079] See also Figure 5 From the EPR graph, it can be seen that the EPR signal at g = 2.003 corresponds to the presence of oxygen defect sites. The signal intensity of the catalyst after the addition of samarium is significantly greater than that of the nickel / MCM-41 molecular sieve catalyst, confirming that the synergistic effect of the nickel-samarium bimetallic promotes the formation of a large number of oxygen defect sites. This is conducive to promoting the adsorption and activation of CO2 during the reaction process, forming active O* intermediate species, and thus promoting the removal of carbon deposits.

[0080] Experimental Example 2

[0081] Performance test of catalytic methane dry reforming to synthesis gas over Ni-Samarium bimetallic synergistic / MCM-41 molecular sieve catalyst

[0082] Test method: Take 0.05-0.4g of catalyst, grind it with inert silicon carbide solid phase at a mass ratio of 1:4 for 10 minutes, put it into a vertical micro fixed bed reactor, and carry out catalytic reaction after reduction treatment at 550-750℃ for 4 hours in a 100mL / min 10vol% H2 / N2 flow, wherein the molar ratio of methane to carbon dioxide in the feed is 1, and the gas feed space velocity is 40000-120000mL·h -1 ·g cat-1 , the reaction temperature is 650-850° C. The specific reaction conditions and results are shown in Tables 1 and 2.

[0083] Table 1

[0084]

[0085]

[0086] Table 2

[0087]

[0088] Table 1 shows the catalytic effect of each catalyst at the 5th hour under the corresponding reaction conditions, and Table 2 shows the deactivation inflection point time of each catalyst and the catalytic effect at that time. It can be concluded that the catalyst of the present invention can still show a relatively high methane / carbon dioxide conversion rate in the 700-hour catalytic CH4-CO2 reforming reaction to produce synthesis gas, and the conversion rate of the catalyst with the synergistic effect of the nickel-samarium bimetallic catalyst exceeds 80%, and the H2 / CO ratio in the synthesis gas is 0.8-1.2, indicating that the catalyst has good stability and a long service life. Among them, 10Ni1Sm / MCM-41 has the best catalytic performance, and the deactivation time exceeds 1000 hours, with ultra-long durability.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst, characterized in that: The invention comprises a carrier and active components loaded on the carrier, wherein the carrier is MCM-41 molecular sieve, and the active components are nickel and samarium.

2. The nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst according to claim 1, characterized in that: The nickel content is 5-20wt%, the samarium content is 1-20wt%, and the balance is MCM-41 molecular sieve.

3. The method for preparing the nickel-samarium bimetallic synergy / MCM-41 molecular sieve catalyst according to claim 1 or 2, characterized in that: The following steps are involved: (1) dissolving nickel and samarium precursor salts in deionized water, adding ammonia water to obtain an alkaline nickel-samarium ammine complex solution, adding MCM-41 molecular sieves to the alkaline nickel-samarium ammine complex solution, and then heating and stirring the solution under closed conditions, and then heating and evaporating the solution until the pH value reaches neutral, to obtain a reaction mixture; (2) The reaction mixture is centrifuged, the obtained solid is dried, ground into powder, and finally calcined in an air atmosphere to obtain the nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst.

4. The method for preparing the nickel-samarium bimetallic synergy / MCM-41 molecular sieve catalyst according to claim 3, characterized in that: In step (1), the amount of ammonia water added is such that the pH value reaches 10 to 12, and the stirring treatment is carried out at room temperature for 8 to 12 hours.

5. The method for preparing the nickel-samarium bimetallic synergy / MCM-41 molecular sieve catalyst according to claim 3, characterized in that: In step (1), the heating and evaporation temperature is 60 to 90°C.

6. The method for preparing the nickel-samarium bimetallic synergy / MCM-41 molecular sieve catalyst according to claim 3, characterized in that: In step (2), the drying conditions are 80-110° C. and 8-12 h.

7. The method for preparing the nickel-samarium bimetallic synergy / MCM-41 molecular sieve catalyst according to claim 3, characterized in that: In step (2), the specific process of calcination treatment is: heating the temperature to 550-700° C. at a heating rate of 1-5° C. / min, and then calcining at this temperature for 2-6 hours.

8. Use of the nickel-samarium bimetallic synergistic / MCM-41 molecular sieve catalyst as claimed in claim 1 or 2 in catalytic methane dry reforming to produce synthesis gas.

9. A method for preparing synthesis gas by catalytic dry reforming of methane, characterized in that: The following steps are involved: The catalyst as claimed in claim 1 or 2 is reduced in a 10 vol% H2 / N2 atmosphere at a temperature of 550-750°C for 2-4 hours, and then mixed with inert silicon carbide to catalyze methane dry reforming to produce synthesis gas in a reactor.

10. The method for preparing synthesis gas by catalytic dry reforming of methane as claimed in claim 9, characterized in that: The catalyst and inert silicon carbide are mixed in a mass ratio of 1:2-5 by solid phase grinding for 10-15 minutes. The reaction conditions are: the molar ratio of CH4 to CO2 in the reaction feed is 1-2, and the gas feed space velocity is 40000-120000 mL·h -1 ·gcat -1 , the catalyst dosage is 0.05~0.5g, and the reaction temperature is 550~850℃.

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