A defective-rich metal oxide encapsulated nickel / attapulgite-based zsm-5 zeolite catalyst, its preparation method and application

Abstract

The application discloses a kind of rich defect metal oxide encapsulation nickel / hopalolite-based ZSM-5 zeolite catalyst, comprising: carrier hopalolite-based ZSM-5 zeolite, and active component nickel and rich defect metal oxide encapsulation layer constructed by metal element loaded on the carrier, metal element is selected from any one or any multiple in zirconium, cerium, iron, molybdenum.The catalyst of the application is applied to catalyze CH4-CO2 reforming to synthesis gas reaction, can significantly enhance the adsorption activation capacity of catalysis to CH4, CO2 molecule, with high CH4, CO2 conversion rate, and show good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of methane dry reforming, in particular to a defective metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst and a preparation method and application thereof. BACKGROUND

[0002] Direct emission of low-concentration coal mine gas (methane concentration less than 30%) leads to a large amount of resource waste and serious greenhouse effect. Therefore, in the current world background of environmental pollution and resource scarcity, it is imperative to take effective measures to resource utilization of the emitted methane and other greenhouse gases such as carbon dioxide.

[0003] The methane dry reforming (DRM) reaction was first reported in 1888. In 1928, Fischer and Tropsch found that the Ni-based catalyst could effectively promote the catalytic conversion of methane in the DRM process, and it was pointed out that the development of high-performance Ni-based catalysts was always one of the keys to the catalytic CH4-CO2 reforming to prepare synthesis gas. In 1988, Fischer and Tropsch found that the NiCo / Al2O3 catalyst with Ni and Co as active components and Al2O3 as carrier had good DRM activity in the temperature range of 1033K-1273K. Moreover, compared with the low reserve and high price of noble metal catalysts (such as Rh, Ru, Pt, Pd), the high economic applicability and high C-H bond cleavage activity of the Ni-based catalyst make it have more development potential.

[0004] However, a large number of research results show that the Ni-based catalyst has poor process stability in the process of catalytic DRM to prepare synthesis gas, mainly because the Ni-based catalyst is easy to be deactivated due to surface carbon deposition and active component sintering. Therefore, how to improve the carbon deposition resistance and sintering resistance of the Ni-based catalyst has become the key to further industrial application and large-scale preparation of synthesis gas by methane dry reforming. SUMMARY

[0005] The main purpose of the present application is to provide a defective metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst which can catalyze the reforming of coal mine gas to synthesis gas and has better stability, and a preparation method and application thereof.

[0006] To achieve the above purpose, the present application provides a defective metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst, which comprises a carrier attapulgite-based ZSM-5 zeolite, and an active component nickel and a defective metal oxide encapsulation layer constructed by metal elements loaded on the carrier, the metal elements being selected from any one or any plurality of zirconium, cerium, iron and molybdenum.

[0007] Further, the nickel content is 1-10 wt%, and the metal oxide content is 0.1-2 wt%.

[0008] Further, the preparation method of the attapulgite-based ZSM-5 zeolite comprises the following steps:

[0009] The attapulgite clay is treated in a 150-220℃ hydrochloric acid solution with a concentration of 3-10 mol / L for 12-48h to obtain an attapulgite-based silicon source; the attapulgite-based silicon source is mixed with tetrapropylammonium hydroxide and sodium hydroxide at a mass ratio of 1:0.95-1.25:0.002-0.10, and then hydrothermal crystallization is performed at 150-220℃ for 40-150h; finally, washing, vacuum drying at 60-80℃ for 12-24h, and calcination at 550-700℃ under an air atmosphere at a temperature rising rate of 1-5℃ / min for 5-10h are performed to obtain the attapulgite-based ZSM-5 zeolite.

[0010] The application further provides a preparation method of the above catalyst, comprising the following steps:

[0011] (1) taking the attapulgite-based ZSM-5 zeolite and a precursor salt of nickel, and loading the nickel on the attapulgite-based ZSM-5 zeolite by an impregnation method to obtain a nickel / attapulgite-based ZSM-5 zeolite;

[0012] (2) taking the nickel / attapulgite-based ZSM-5 zeolite, ethylene glycol, and a precursor salt of a metal oxide, and constructing a defect-rich metal oxide encapsulation layer on the nickel / attapulgite-based ZSM-5 zeolite by a co-hydrothermal crystallization coupling high-temperature calcination to obtain the defect-rich metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst.

[0013] Further, the specific process of step (1) is as follows:

[0014] The nitrate or sulfate salt of nickel is used as the precursor salt, dissolved in deionized water at a mass ratio of 1:100-200, and then the attapulgite-based ZSM-5 zeolite is added; after stirring at room temperature for 8-12h, water is evaporated at 80-120℃, and then drying is performed under vacuum at 60-80℃ for 12-24h; finally, calcination is performed at 550-700℃ under an air atmosphere at a temperature rising rate of 1-5℃ / min for 5-10h.

[0015] Further, the specific process of step (2) is as follows:

[0016] The nickel / pillared attapulgite-based ZSM-5 zeolite, ethylene glycol and deionized water are mixed in a mass / volume ratio of 1 g: 7-15 mL: 15-25 mL, hydrothermally crystallized at 100-150 ℃ for 10-24 h, and then calcined at 550-700 ℃ for 5-10 h at a temperature rising rate of 1-5 ℃ / min in a 10 vol% H2 / N2 or air atmosphere.

[0017] The application also provides the application of the above-mentioned nickel / pillared attapulgite-based ZSM-5 zeolite catalyst encapsulated by a defect-rich metal oxide in catalyzing the reforming of coal mine gas into synthetic gas.

[0018] The application also provides a method for catalyzing the reforming of CH4-CO2 into synthetic gas, which comprises the following steps: reducing the above-mentioned catalyst in a 10 vol% H2 / N2 atmosphere at 650-750 ℃ for 2-4 h, and then performing the catalytic reforming of CH4-CO2 into synthetic gas in a vertical micro fixed-bed reactor.

[0019] Further, the reaction conditions are as follows: the catalyst is uniformly mixed with inert silicon carbide at a mass ratio of 1:2-5 by solid-phase grinding for 10-15 min, the molar ratio of CH4 to CO2 in the reaction feed is 1-1.25, the gas feed space velocity is 40,000-120,000 mL·h -1 ·gcat -1 ·gcat

[0020] In the implementation of the application, the inventors have found that under the reaction conditions, the catalyst has a high methane / carbon dioxide conversion rate of more than 80% in the catalytic reforming of CH4-CO2 into synthetic gas for 700 h, and the H2 / CO ratio in the synthetic gas is 0.8-1.2.

[0021] Attapulgite is a silico-aluminate with a high silicon content. In the synthesis of the attapulgite-based ZSM-5 zeolite carrier by hydrothermal crystallization under the action of inorganic alkali and a template agent with attapulgite as a silicon source, the high structural stability of attapulgite is retained, and the specific surface area and pore structure are optimized, which is beneficial to the high dispersion of nickel metal.

[0022] Compared with the nickel / attapulgite-based ZSM-5 zeolite, the construction of the defect-rich metal oxide encapsulation layer not only improves the sintering resistance of the active metal through the interaction with the active component and the carrier, but also is beneficial to promoting the activation of CO2 and increasing the number of active oxygen species on the catalyst surface, thereby promoting the removal of carbon deposition.

[0023] Fe2O3, CeO2, ZrO2, Mo2O3 as a multivalent metal oxide has good redox performance and high oxygen migration rate, the present application by preparing rich defect metal oxide encapsulation nickel / attapulgite-based ZSM-5 zeolite, it is favorable to promote the removal of catalyst surface carbon, and it is simultaneously improved metal-support / metal oxide interlayer interaction, realizes the anchoring of active metal nickel.

[0024] The beneficial effects of the present application are embodied in:

[0025] 1.The catalyst has the characteristics of green economy and high structural stability, and when applied to the reaction of catalytic CH4-CO2 reforming to produce synthesis gas, it shows high methane / dioxide conversion rate, which is more than 80%, and the H2 / CO ratio in the synthesis gas is 0.8-1.2 in the 700h catalytic CH4-CO2 reforming to produce synthesis gas.

[0026] 2.The catalyst uses nickel as an active metal, which can ensure that the catalyst has high cracking methane C-H bond activity, and the use of attapulgite-based ZSM-5 zeolite carrier saves the preparation cost of the catalyst and promotes the dispersion of the active component.

[0027] 3.Compared with other nickel-based catalysts, the catalyst of the present application enhances the interaction between the active component and the carrier by constructing a rich defect metal oxide encapsulation layer, improves the sintering resistance of the active metal, and the catalyst surface has a high oxygen defect concentration, which 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 deposition. Therefore, the catalyst has high sintering resistance, carbon deposition resistance and catalytic stability, which meets the requirements of industrial catalysts.

[0028] 4.The catalyst is applied to the reaction of catalytic CH4-CO2 reforming to produce synthesis gas, which can significantly enhance the adsorption and activation ability of the catalyst to CH4 and CO2 molecules, has high CH4 and CO2 conversion rate, and has good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 XRD pattern of attapulgite-based ZSM-5 zeolite;

[0030] Figure 2 N2 adsorption-desorption isotherm graph of attapulgite-based ZSM-5 zeolite;

[0031] Figure 3 Pore size distribution graph of attapulgite-based ZSM-5 zeolite;

[0032] Figure 4 FTIR spectrum of attapulgite-based ZSM-5 zeolite;

[0033] Figure 5 TEM image of nickel / attapulgite-based ZSM-5 zeolite encapsulated by ceria;

[0034] Figure 6 HRTEM image of nickel / attapulgite-based ZSM-5 zeolite encapsulated by ceria and corresponding lattice fringe spacing analysis image;

[0035] Figure 7 EPR image of nickel / attapulgite-based ZSM-5 zeolite and 2# catalyst prepared in Example 3. DETAILED DESCRIPTION

[0036] The present application will be further described in detail with specific examples.

[0037] The raw materials used in the examples of the present application are commercially available or can be obtained by those skilled in the art, unless otherwise specified. The methods used in the examples of the present application are mastered by those skilled in the art, unless otherwise specified.

[0038] Example 1

[0039] Preparation of carrier attapulgite-based ZSM-5 zeolite

[0040] The attapulgite-based ZSM-5 zeolite is prepared as follows: 20 g of attapulgite clay is treated in a 200℃, 120 mL 6 mol / L hydrochloric acid solution for 12 h, filtered and washed, dried at 100℃ for 12 h to obtain an attapulgite-based silicon source; 2 g of the attapulgite-based silicon source is mixed with tetrapropylammonium hydroxide and sodium hydroxide at a mass ratio of 1:1:0.08, hydrothermally crystallized at 180℃ for 72 h, centrifuged and washed, vacuum dried at 80℃ for 12 h, heated to 650℃ at a rate of 4℃ / min in an air atmosphere and held at a constant temperature for 6 h to obtain the attapulgite-based ZSM-5 zeolite.

[0041] Example 2

[0042] The active ingredient nickel in the nickel / attapulgite-based ZSM-5 zeolite catalyst encapsulated by the defect-rich metal oxide prepared in this example is 5 wt%, the content of iron oxide is 0.28 wt%, and the remaining component is the attapulgite-based ZSM-5 zeolite carrier. The preparation method is as follows:

[0043] Take 5 g of attapulgite-based ZSM-5 zeolite, 1.3305 g of nickel nitrate hexahydrate, and dissolve in 200 mL of deionized water, stir at room temperature for 8 h, evaporate water at 90°C, vacuum dry at 80°C for 12 h, air atmosphere, 4°C / min heating rate to 700°C and constant temperature calcination for 6 h to obtain nickel / attapulgite-based ZSM-5 zeolite. Take 1 g of nickel / attapulgite-based ZSM-5 zeolite, 0.0072 g of iron nitrate nonahydrate, 10 mL of ethylene glycol, 20 mL of deionized water, stir to uniformity, then move into a polytetrafluoroethylene-lined hydrothermal synthesis kettle, hydrothermal crystallization at 120°C for 24 h, centrifugal washing, drying, 100 mL / min air atmosphere, 5°C / min heating rate to 700°C and constant temperature calcination for 5 h, to obtain the said defect-rich metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite, No. 1 catalyst.

[0044] Example 3

[0045] The active ingredient nickel content in the defect-rich metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst prepared in this example is 10 wt%, the content of cerium dioxide is 1.20 wt%, and the remaining component is an attapulgite-based ZSM-5 zeolite carrier. The preparation method is as follows:

[0046] Take 5 g of attapulgite-based ZSM-5 zeolite, 2.8089 g of nickel nitrate hexahydrate, and dissolve in 200 mL of deionized water, stir at room temperature for 8 h, evaporate water at 90°C, vacuum dry at 80°C for 12 h, air atmosphere, 4°C / min heating rate to 700°C and constant temperature calcination for 6 h to obtain nickel / attapulgite-based ZSM-5 zeolite. Take 1 g of nickel / attapulgite-based ZSM-5 zeolite, 0.0314 g of cerium nitrate hexahydrate, 10 mL of ethylene glycol, 20 mL of deionized water, stir to uniformity, then move into a polytetrafluoroethylene-lined hydrothermal synthesis kettle, hydrothermal crystallization at 120°C for 24 h, centrifugal washing, drying, 100 mL / min 10 vol% H2 / N2 atmosphere, 3°C / min heating rate to 700°C and constant temperature calcination for 5 h, to obtain the said defect-rich metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite, No. 2 catalyst.

[0047] Example 4

[0048] The active ingredient nickel content in the defect-rich metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst prepared in this example is 10 wt%, the content of cerium dioxide is 1.20 wt%, and the remaining component is an attapulgite-based ZSM-5 zeolite carrier. The preparation method is as follows:

[0049] Weigh 5g of attapulgite-based ZSM-5 zeolite and 1.9028g of nickel nitrate hexahydrate and dissolve them in 200mL of deionized water. After stirring at room temperature for 8 hours, evaporate the water at 90℃, vacuum dry at 80℃ for 12 hours, and calcine at 700℃ in air at a heating rate of 4℃ / min for 6 hours to obtain nickel / attapulgite-based ZSM-5 zeolite. Take 1g of nickel / attapulgite-based ZSM-5 zeolite, 0.0236g of zirconium nitrate pentahydrate, 10mL of ethylene glycol, and 20mL of deionized water, stir until uniform, and transfer to a polytetrafluoroethylene-lined hydrothermal synthesis vessel. Hydrothermally crystallize at 120℃ for 24 hours, centrifuge, wash, and dry, and calcine at 700℃ in 10vol% air at a heating rate of 4℃ / min for 5 hours to obtain the defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite, designated as catalyst #3.

[0050] Example 5

[0051] The nickel / attapulgite-based ZSM-5 zeolite catalyst encapsulated with defect-rich metal oxide prepared in this embodiment contains 2 wt% nickel and 1.49 wt% molybdenum oxide, with the remaining component being an attapulgite-based ZSM-5 zeolite support. The preparation method is as follows:

[0052] Weigh 5g of attapulgite-based ZSM-5 zeolite and 0.5159g of nickel nitrate hexahydrate and dissolve them in 200mL of deionized water. After stirring at room temperature for 8 hours, evaporate the water at 90℃, vacuum dry at 80℃ for 12 hours, and calcine at 700℃ in air at a heating rate of 4℃ / min for 6 hours to obtain nickel / attapulgite-based ZSM-5 zeolite. Take 1g of nickel / attapulgite-based ZSM-5 zeolite, 0.1314g of ammonium molybdate tetrahydrate, 10mL of ethylene glycol, and 20mL of deionized water, stir until homogeneous, and transfer to a polytetrafluoroethylene-lined hydrothermal synthesis reactor. Perform hydrothermal crystallization at 120℃ for 24h. After centrifugation, washing, and drying, heat the mixture to 700℃ at a rate of 3℃ / min in a 100mL / min 10vol% H2 / N2 atmosphere and calcine it at this temperature for 5h to obtain the defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite, designated as catalyst #4.

[0053] Example 6

[0054] Structural determination of defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst

[0055] Structural analysis was performed on the support prepared in Example 1 and the catalyst No. 2 prepared in Example 3. The results are as follows: Figures 1 to 7 As shown.

[0056] See Figure 1 XRD patterns of attapulgite-based ZSM-5 zeolite Figure 2The characteristic diffraction peaks corresponding to MFI-type topology were detected at 7.97°, 8.82°, 23.08° and 23.95°, which proved that ZSM-5 zeolite material could be successfully prepared using palygorskite as silicon source.

[0057] Referring to Figure 2 , according to IUPAC classification, the palygorskite-based ZSM-5 zeolite exhibited type I and type II composite isotherms, accompanied by type H4 hysteresis loop. This indicated that the synthesized palygorskite-based ZSM-5 zeolite had composite pores composed of ordered micropores and mesopores formed by zeolite layer stacking.

[0058] Referring to Figure 3 , the palygorskite-based ZSM-5 zeolite exhibited a pore size distribution centered at 0.5 nm and 2.5 nm, which further proved the existence of such micropore-mesopore composite pore structure, which was beneficial to promote the dispersion of active metals on the surface of the carrier and promote the reaction mass transfer.

[0059] Referring to Figure 4 , the FTIR spectrum of the palygorskite-based ZSM-5 zeolite. The adsorption bands detected at about 3450 and 1640 cm -1 corresponded to the stretching vibration of surface hydroxyl groups and adsorbed water, respectively, while the characteristic bands appearing at 680 and 510 cm -1 corresponded to the vibration of Si-O-Al / Mg and Si-O-Si bonds. The characteristic bands detected at 1230, 1095, 796, 540 and 460 cm -1 belonged to MFI-type topology, in which the characteristic band at 540 cm -1 was due to the presence of double five-membered rings in the MFI-type topology framework. The above vibration bands all existed in the palygorskite-based ZSM-5 zeolite, which further proved the feasibility of preparing ZSM-5 zeolite material using palygorskite as silicon source.

[0060] Referring to Figure 5 , the TEM image of ceria-encapsulated nickel / palygorskite-based ZSM-5 zeolite shown in FIG. 5, it can be observed that the active metal was highly dispersed on the surface of the lamellar palygorskite-based ZSM-5 zeolite carrier, which was beneficial to expose more active centers and promote the adsorption and activation of methane molecules in the process of catalyzing CH4-CO2 reforming to synthesize gas. In addition, by Figure 6The HRTEM image of the ceria-encapsulated nickel / palygorskite-based ZSM-5 zeolite and the corresponding lattice fringe spacing analysis show that the nickel metal particles are partially coated by ceria, which proves the successful synthesis of the metal oxide-encapsulated nickel / palygorskite-based ZSM-5 zeolite structure. This incomplete encapsulation structure not only can anchor the nickel active metal in the process of catalyzing the CH4-CO2 reforming reaction to produce synthetic gas at high temperature, but also will not cover the active center, resulting in a significant decrease in catalyst activity.

[0061] Referring to Figure 7 The electron paramagnetic resonance (EPR) images of the nickel / palygorskite-based ZSM-5 zeolite and the 2# catalyst are shown. The EPR signal at g = 2.003 corresponds to the presence of oxygen defect sites. The signal intensity of the 2# catalyst is significantly greater than that of the nickel / palygorskite-based ZSM-5 zeolite, which confirms that the construction of the oxide encapsulation layer promotes the formation of a large number of oxygen defect sites. This is beneficial to promote the adsorption and activation of CO2 in the reaction process, forming active O* intermediate species, thereby promoting the removal of carbon deposition.

[0062] Example 7

[0063] Performance test of the defect-rich metal oxide-encapsulated nickel / palygorskite-based ZSM-5 zeolite catalyst for catalyzing the CH4-CO2 reforming reaction to produce synthetic gas

[0064] Low-concentration coal mine gas is a mixture of laboratory pure methane diluted by nitrogen: 0.05-0.4 g of the above 1#-4# catalyst is taken and ground with inert silicon carbide solid phase at a mass ratio of 1:4 for 10 min, and then the performance test is carried out in a vertical micro fixed bed reactor after reduction treatment at 650-750℃ for 2-6 h in a 100 mL / min 10 vol% H2 / N2 stream, wherein the molar ratio of methane to carbon dioxide in the feed is 1, the gas feed space velocity is 40000-120000 mL·h -1 ·g cat -1 , and the reaction temperature is 650-850℃. The specific reaction conditions and results are shown in Table 1.

[0065] Table 1

[0066]

[0067] Performance test of the defect-rich metal oxide-encapsulated nickel / palygorskite-based ZSM-5 zeolite catalyst for catalyzing the CH4-CO2 reforming reaction to produce synthetic gas

[0068] The low-concentration coal mine gas is respectively from the coal bed gas of PetroChina, the coal bed gas of Shanxi, the coal bed gas of Zhonglian, and the coal bed gas of Orian: 0.05-0.4 g of the above 1#-4# catalysts is ground with inert silicon carbide solid phase at a mass ratio of 1:4 for 10 min, then the performance test is carried out after reduction treatment at 650-750 DEG C for 2-6 h in a 100 mL / min 10vol% H2 / N2 flow in a vertical micro fixed bed reactor, wherein the molar ratio of methane to carbon dioxide in the feed is 1, and the gas feed space velocity is 40000-120000 mL·h -1 ·g cat -1 , the reaction temperature is 650-850 DEG C. The specific reaction conditions and results are shown in Table 2.

[0069] Table 2

[0070]

[0071]

[0072] From the above results, it can be concluded that the catalyst of the present application can still exhibit a higher methane / carbon dioxide conversion rate in the 700 h catalytic CH4-CO2 reforming reaction for preparing synthesis gas, and the conversion rate is all more than 80%, and the H2 / CO ratio in the synthesis gas is 0.8-1.2, which indicates that the catalyst has good stability and long service life.

[0073] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst, characterized in that, include: The carrier is attapulgite-based ZSM-5 zeolite, and the active component nickel and the defect-rich metal oxide encapsulation layer constructed from metal elements are loaded on the carrier. The metal elements are selected from any one or any combination of zirconium, cerium, iron and molybdenum. The preparation method of the defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst includes the following steps: (1) Take attapulgite-based ZSM-5 zeolite and nickel precursor salt, and load nickel onto attapulgite-based ZSM-5 zeolite by impregnation method to obtain nickel / attapulgite-based ZSM-5 zeolite. (2) Take nickel / attapulgite-based ZSM-5 zeolite, ethylene glycol and metal oxide precursor salt, and use co-hydrothermal crystallization coupled high-temperature calcination to construct a defect-rich metal oxide encapsulation layer on nickel / attapulgite-based ZSM-5 zeolite to obtain the defect-rich metal oxide encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst. The specific process of step (2) is as follows: Nickel / attapulgite-based ZSM-5 zeolite, precursor salt of metal oxide, ethylene glycol and deionized water are mixed. The mass-volume ratio of nickel / attapulgite-based ZSM-5 zeolite, ethylene glycol and deionized water is 1g:7~15mL:15~25mL. Hydrothermal crystallization is carried out at 100~150℃ for 10~24h. Then, the mixture is calcined at 550~700℃ for 5~10h in 10vol%H2 / N2 or air atmosphere at a heating rate of 1~5℃ / min.

2. The defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst as described in claim 1, characterized in that, The nickel content is 1–10 wt%, and the metal oxide content is 0.1–2 wt%.

3. The defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst as described in claim 1 or 2, characterized in that, The preparation method of attapulgite-based ZSM-5 zeolite includes the following steps: Attapulgite clay was treated in a 3-10 mol / L hydrochloric acid solution at 150-220℃ for 12-48 hours to obtain an attapulgite-based silicon source. The attapulgite-based silicon source was mixed with tetrapropylammonium hydroxide and sodium hydroxide at a mass ratio of 1:0.95-1.25:0.002-0.10, and then hydrothermally crystallized at 150-220℃ for 40-150 hours. Finally, the mixture was washed, vacuum dried at 60-80℃ for 12-24 hours, and calcined in air at a heating rate of 1-5℃ / min to 550-700℃ for 5-10 hours to obtain the attapulgite-based ZSM-5 zeolite.

4. The defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst as described in claim 1 or 2, characterized in that, The specific process of step (1) is as follows: Nickel nitrate or sulfate is used as a precursor salt and dissolved in deionized water at a mass ratio of 1:100-200. Attapulgite-based ZSM-5 zeolite is added, and the mixture is stirred at room temperature for 8-12 hours. The water is then evaporated at 80-120℃, dried under vacuum at 60-80℃ for 12-24 hours, and finally calcined in air at a heating rate of 1-5℃ / min to 550-700℃ for 5-10 hours.

5. The application of the defect-rich metal oxide-encapsulated nickel / attapulgite-based ZSM-5 zeolite catalyst as described in any one of claims 1 to 4 in the catalytic reforming of coal mine gas to produce syngas.

6. A method for catalytic reforming of CH4-CO2 to produce syngas, characterized in that, Includes the following steps: The catalyst as described in any one of claims 1 to 4 is reduced in a 10 vol% H2 / N2 atmosphere at 650–750 °C for 2–4 h, and then subjected to catalytic CH4-CO2 reforming to syngas reaction in a vertical micro fixed-bed reactor.

7. The method for producing syngas by catalytic reforming of CH4-CO2 as described in claim 6, characterized in that: The reaction conditions were as follows: catalyst dosage was 0.05–0.4 g, and it was mixed with inert silicon carbide at a mass ratio of 1:2–5 by solid-phase grinding for 10–15 min to achieve uniform mixing; the molar ratio of CH4 to CO2 in the reaction feed was 1–1.25; and the gas hourly space velocity was 40,000–120,000 mL·h. -1 ·gcat -1 The reaction temperature is 650–850℃.

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