Methane reforming composite catalyst and preparation method thereof

Abstract

The application provides a methane reforming composite catalyst and a preparation method thereof. The method can realize in-situ composite of a Ni-Ca-In-Al four-metal layered double hydroxide catalyst and a layered nickel silicate catalyst in one step. The catalyst has abundant micro and macro pore structures, and the CO2 adsorption and activation performance is significantly improved at high temperature, and the catalyst has good reaction activity and performance stability. In the catalyst, the metal nickel is highly dispersed, and the metal nickel is not easy to sinter; the adsorption and activation of CO2 molecules are strengthened, and the reaction activity is improved; the hydrophilic fumed silica is used as a hard template, and the hard template can be directly removed in the preparation process, the macro structure of the catalyst is effectively controlled, and the anti-carbon deposition performance is further improved. The preparation method is simple and easy to implement, additional catalyst composite steps are avoided, the requirement for equipment is low, the catalyst yield is high, and the catalyst yield can meet the demand of large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the field of industrial catalysis, specifically relating to a methane reforming composite catalyst and its preparation method. Background Technology

[0002] Methane reforming is widely recognized as a promising energy utilization technology. Currently, commonly used methane reforming technologies include steam methane reforming (SMR), dry methane reforming with carbon dioxide (DRM), partial oxidation reforming of methane (POX), and combined methane reforming. Despite over a century of development, catalyst coking remains a key technological bottleneck in this field.

[0003] Currently, methane reforming catalysts are mainly nickel-based, containing primarily metallic nickel, alumina, and small amounts of additives. Thermodynamic equilibrium studies show that in methane steam reforming systems, the presence of abundant water vapor results in low coking yield and ideal catalyst lifetime. However, in dry reforming systems with low water-to-carbon ratios or even no water vapor, methane decomposition and carbon monoxide disproportionation both lead to coking. Since carbon dioxide's decoking ability is far weaker than that of water vapor, coking accumulates rapidly on the catalyst surface, causing pore blockage, nickel sintering, and ultimately deactivation. Furthermore, carbon dioxide has higher chemical stability and is less likely to participate in the reaction than water vapor, thus requiring higher requirements for the surface area, dispersion, and basic active sites of metallic nickel on the catalyst.

[0004] To address existing problems with methane reforming catalysts, techniques such as controlling catalyst composition, improving catalyst crystal structure, and achieving multi-catalyst composites are widely used to enhance the catalytic performance of methane reforming catalysts. Due to the high cost of rare and precious metals, nickel-based catalysts remain the preferred choice for industrial applications, and various forms such as bimetallic catalysts and single-atom catalysts have emerged in recent years. Among them, layered nickel silicate catalysts exhibit high nickel dispersion, thus maintaining good performance stability in long-cycle dry reforming reactions. However, experiments have shown that this catalyst and its derived mechanically mixed catalysts have poor water vapor resistance, and the nickel grains tend to grow easily, indicating significant room for optimization.

[0005] In summary, existing methane reforming catalysts still suffer from problems such as scarce and disordered pores, poor dispersion of active metals, and easy carbon deposition and deactivation. Summary of the Invention

[0006] The purpose of this invention is to provide a methane reforming composite catalyst that comprehensively improves the catalyst's activity and anti-coking performance through structural and formulation improvements.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A methane reforming composite catalyst, wherein the catalyst is an in-situ composite catalyst of a Ni-Ca-In-Al tetrametallic layered bimetallic hydroxide catalyst and a layered nickel silicate catalyst, the two being combined via nickel as a medium, and its general chemical formula is: α[Ni i Ca j In k Al l [(OH)2](CO3) (k+l) / 2 ·βNi3Si4O 10 (OH)2; where 0.6≤(α×i) / β≤6, i+j+k+l=1, and 0<i<1、0<j<1、0<k<1、0<l<1, and 0.2≤(i+j) / (k+l)≤1.2.

[0009] This invention proposes a one-step method for preparing an in-situ composite catalyst of Ni-Ca-In-Al tetrametal layered bimetallic hydroxide catalyst and layered nickel silicate catalyst. Hydrophilic fumed silica is used as a hard template, and the novel Ni-Ca-In-Al tetrametal layered bimetallic hydroxide catalyst is used as a performance promoter, thereby improving the catalyst's activity and anti-coking performance. In this process, metallic Ni is strictly confined to the [NiO6] octahedra of Ni-Ca-In-Al tetrametallic layered bimetallic hydroxide and layered nickel silicate, respectively. Not only are there O barriers between metallic Ni, but Ca, In, Al, Si and other elements further ensure its dispersion, resulting in a stable structure, uniform dispersion and resistance to agglomeration. Ca and In are used as the main substitutes for Ni in the [NiO6] octahedra, fixing it in the layered structure and providing basic active sites during the reaction to enhance CO2 adsorption and activation, thus accelerating the reaction. Hydrophilic fumed silica serves as a hard template and is removed simultaneously during the preparation process, leaving a three-dimensional dendritic structure inside the catalyst, effectively controlling the macroscopic structure of the catalyst and further improving its anti-coking performance.

[0010] Another objective of this invention is to provide a method for preparing a methane reforming composite catalyst.

[0011] A method for preparing the above-mentioned methane reforming composite catalyst, the method comprising the following steps:

[0012] S1: Mix silica with water to form a suspension M1; dissolve Ni salt, Ca salt, In salt and Al salt in water to prepare a quaternary mixed metal salt solution M2;

[0013] S2: Add M2 to M1 to obtain a mixed solution M3; add urea and dissolve to obtain M4;

[0014] S3: Transfer M4 to a high-pressure reactor, keep it warm, stir, cool it down, filter and collect the solid product, wash and dry it to obtain the catalyst precursor;

[0015] S4: High-temperature calcination of the catalyst precursor yields the target catalyst product.

[0016] In this invention, the silica in S1 is hydrophilic fumed silica; preferably, the mass ratio of silica to water is 5 to 20:100.

[0017] In this invention, the processing in S1 is ultrasonic treatment under a slight negative pressure condition; preferably, the pressure range of the slight negative pressure is 0.1 to 5 kPaA, and the ultrasonic treatment time is 10 to 30 min.

[0018] In this invention, the quaternary mixed metal salt in S1 is a salt with the same acid radical, preferably both being nitrates or both being chlorides; preferably, the total molar concentration of metal ions in the quaternary mixed metal salt solution is 0.5 to 1.5 mol / L.

[0019] In this invention, the volume ratio of M2 to M1 in S2 is 1.5:1 to 0.8:1.

[0020] In this invention, the amount of urea added to S2 is 1.5 to 5 times the total molar content of metal ions in M2.

[0021] In this invention, the temperature of the high-pressure reactor in S3 is 150-200℃, and the holding time is 18-60hr.

[0022] In this invention, the calcination temperature in S4 is 400–600°C, and the time is 2–8 hours.

[0023] Another object of the present invention is to provide a use for a composite catalyst.

[0024] The use of a composite catalyst, wherein the catalyst is the catalyst described above, or a catalyst prepared by the method described above, the catalyst being used for catalytic methane reforming.

[0025] In this invention, the catalyst is activated before being used for catalytic methane reforming; preferably, the reducing gas in the activation medium is H2 and / or CO, and preferably the content of the reducing gas is not less than 5 vol.%; preferably, the activation temperature is 550-800℃ and the activation time is 2-4 hours.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] (1) It has a good microstructure and nickel dispersion. The metallic Ni is uniformly dispersed and does not easily agglomerate and sinter, which ensures both high activity and long life.

[0028] (2) The introduction of Ca enhances the adsorption and activation of CO2 molecules, accelerates the reaction, and improves the catalyst activity.

[0029] (3) Using hydrophilic fumed silica as a hard template leaves a three-dimensional dendritic structure inside the catalyst, which effectively regulates the macroscopic structure of the catalyst and improves its anti-coking performance.

[0030] (4) The in-situ composite of Ni-Ca-In-Al tetrametal layered bimetallic hydroxide catalyst and layered nickel silicate catalyst can be realized in one step. The preparation method is simple and easy to implement, with low equipment requirements and high catalyst yield, which can meet the needs of large-scale industrial production. Attached Figure Description

[0031] Figure 1 The XRD pattern of the catalyst synthesized in Example 1 is shown below.

[0032] Figure 2 The low-temperature nitrogen adsorption-desorption curves are shown for the catalyst synthesized in Example 1. Detailed Implementation

[0033] To better understand the technical solution of the present invention, the following embodiments will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.

[0034] The main raw materials include:

[0035] Hydrophilic fumed silica, Evonik Degussa, A200; Nickel nitrate, Sinopharm, AR; Calcium nitrate, Sinopharm, AR; Indium nitrate, Sinopharm, AR; Aluminum nitrate, Sinopharm, AR; Urea, Sinopharm, AR; Deionized water, homemade.

[0036] Main analytical characteristics:

[0037] Inductively coupled plasma optical generator, Agilent Technologies, USA, 725ICP-OES;

[0038] X-ray diffractometer, Bruker, Germany, D8;

[0039] Physical adsorption instrument, American Mic, ASAP2460, low temperature nitrogen adsorption-desorption, hydrogen programmed temperature-controlled reduction, carbon dioxide programmed temperature-increase desorption;

[0040] Chemisorption analyzer, AutoChem II 2920, USA, pulse chemisorption, high temperature carbon dioxide adsorption.

[0041] Example 1

[0042] Preparation of methane reforming composite catalyst

[0043] Hydrophilic fumed silica (A200, Evonik Degussa) was mixed with deionized water at a solid-liquid mass ratio of 10:100, sonicated at 0.2 kPaA for 15 min, and then stirred continuously at room temperature for 20 min. 100 mL of the suspension was then collected. Ni 2+ Ca 2 + In 3+ Al 3+ Prepare 100 mL of a quaternary mixed metal nitrate solution of nickel nitrate, calcium nitrate, indium nitrate, and aluminum nitrate in a molar ratio of 1:0.3:0.1:1, with a total molar concentration of 1 mol / L for the quaternary mixed metal ions. Slowly add the mixed metal salt solution to the suspension and stir continuously for 30 min. Quickly pour 0.2 mol of urea powder into the above mixed solution and stir continuously until the urea is fully dissolved. Then transfer it to a high-pressure reactor, seal it, and keep it at 160°C with stirring for 48 h. After the temperature of the high-pressure reactor and the material inside the reactor drops to room temperature, open the reactor, collect the powdered solid product by vacuum filtration, wash it repeatedly with deionized water 5 times, and dry it at 105°C to obtain the catalyst precursor. Calcine the catalyst precursor at 450°C for 4 h to finally obtain the catalyst product.

[0044] Catalyst characterization and analysis:

[0045] The chemical composition of the catalyst was analyzed using an inductively coupled plasma optical emission spectrometer (Agilent Technologies, 725ICP-OES), and the results are shown in Table 1. The chemical formula of the catalyst, after conversion, is 2,2[Ni] 0.36 Ca 0.14 In 0.05 Al 0.45 [(OH)2](CO3) 0.25 0.6Ni3Si4O 10 (OH)2.

[0046] Table 1. Chemical composition of the catalyst (wt.%)

[0047] 39.2 24.8 3.1 20.4 29.0

[0048] Its crystal structure was analyzed using an X-ray diffractometer (Bruck, D8, Germany), and characteristic diffraction peaks typical of layered bimetallic hydroxides were observed (see attached image). Figure 1 This indicates that it has a layered structure of layered bimetallic hydroxides at the microscopic level.

[0049] The results of low-temperature N2 adsorption-desorption tests using a physical adsorption instrument (American Mack, ASAP2460) are shown in the appendix. Figure 2The adsorption isotherm of the catalyst shows a step-like upward trend and has obvious hysteresis loop, indicating that the catalyst has a multi-level pore system of "micropores + macropores" and the micropores account for 45%.

[0050] Carbon dioxide temperature-programmed desorption tests were conducted using a chemisorption analyzer (AutoChem II 2920, USA). The results showed that the catalyst contains weakly basic, moderately basic, and strongly basic sites (as shown in Table 2). The high-temperature CO2 adsorption capacity is 2.4 times that of similar commercially available SMR catalysts (Southwest Institute Z111-6 commercial SMR catalyst).

[0051] Table 2 Distribution of basic sites on catalysts

[0052]

[0053]

[0054] Furthermore, the methane reforming composite catalyst prepared according to the method of the present invention has good structural properties.

[0055] The results of physical adsorption analysis (USA Mic, ASAP2460) show that this catalyst has a molecular weight of 265 mg / L. 2 Even after reduction according to the method in Example 2, the specific surface area of ​​the high / g remains as high as 220m². 2 / g, approximately 5 to 15 times that of similar commercially available SMR catalysts; its pore volume is approximately 3 to 10 times that of similar commercially available SMR catalysts, concentrated in the mesoporous region of 3 to 4 nm and the macroporous region of 50 nm and above, respectively.

[0056] Pulse chemisorption tests were conducted using a chemisorption analyzer (AutoChem II 2920, USA). The results showed that the dispersion of metallic nickel after reduction by this catalyst was ≥40%, which is about twice that of similar commercially available SMR catalysts.

[0057] Example 2

[0058] Methane reforming composite catalyst activation

[0059] 5g of the catalyst powder synthesized in Example 1 was evenly spread in a crucible and placed in the middle of the isothermal section of a tube furnace. The furnace was purged with N2 at a flow rate of 30 sccm for 30 min to remove air. Then, a mixture of 5 vol.% H2 and 95 vol.% N2 was introduced at a flow rate of 50 sccm, raising the temperature to 800°C at a rate of 5°C / min and holding for 2 hours. After holding, the furnace was allowed to cool naturally to room temperature in the mixed gas atmosphere, thus completing catalyst activation.

[0060] Example 3

[0061] Catalytic methane steam reforming performance

[0062] The catalyst powder prepared in Example 1 was pressurized into tablets under high pressure to obtain catalyst particles with an average particle size of 20-40 mesh. 2g of catalyst particles were taken and loaded into a fixed-bed reactor. In-situ reduction was carried out under atmospheric pressure using a mixture of 30 vol.% H2 and 70 vol.% N2 at a reduction temperature of 800°C for 2 hours. After reduction, the furnace temperature was maintained at 800°C and the pressure at atmospheric pressure, and the reactor was purged with N2 for 15 minutes. Subsequently, CH4 and steam were introduced at a volume ratio of H2O:CH4 = 2:1 to carry out a methane steam reforming reaction (SMR).

[0063] The results showed that the reaction reached equilibrium after 1 hour, with a methane conversion rate of 98.8% and a hydrogen-to-carbon ratio of 5.1 in the product. No significant deactivation was observed after 100 hours of continuous operation, achieving efficient methane conversion.

[0064] Example 4

[0065] Catalytic performance of dry reforming of methane

[0066] The catalyst powder prepared in Example 1 was pressurized into tablets under high pressure to obtain catalyst particles with an average particle size of 20-40 mesh. 2g of catalyst particles were taken and loaded into a fixed-bed reactor. In-situ reduction was carried out under atmospheric pressure using a mixture of 30 vol.% H2 and 70 vol.% N2 at a reduction temperature of 800°C for 2 hours. After reduction, the furnace temperature was maintained at 800°C and the pressure at atmospheric pressure, and the reactor was purged with N2 for 15 minutes. Subsequently, CH4 and CO2 were introduced at a volume ratio of CO2:CH4 = 1:1 to carry out a dry methane reforming (DRM) reaction.

[0067] The results showed that the reaction reached equilibrium after 1 hour, with a methane conversion rate of 92.5% and a hydrogen-to-carbon ratio of 1.0 in the product. No significant deactivation was observed after 100 hours of continuous operation, achieving efficient methane conversion.

[0068] Example 5

[0069] Catalytic methane co-reforming performance

[0070] The catalyst powder prepared in Example 1 was pressurized into tablets under high pressure to obtain catalyst particles with an average particle size of 20-40 mesh. 2g of catalyst particles were taken and loaded into a fixed-bed reactor. In-situ reduction was carried out under atmospheric pressure using a mixture of 30 vol.% H2 and 70 vol.% N2 at a reduction temperature of 800°C for 2 hours. After reduction, the furnace temperature was maintained at 800°C, and the reactor was purged with N2 for 15 minutes. Subsequently, CH4, CO2, and steam were introduced at a volume ratio of H2O:CO2:CH4 = 1:1:1 to carry out a bi-reforming reaction of methane.

[0071] At atmospheric pressure, the reaction reached equilibrium after 1 hour, with a methane conversion rate of 97.1% and a hydrogen-to-carbon ratio of 1.9 in the product. No significant deactivation was observed after 100 hours of continuous operation.

[0072] When the pressure was increased to 2 MPa, the reaction reached equilibrium after 4 hours, with a methane conversion rate of 64.5% and a hydrogen-to-carbon ratio of 1.2 in the product, achieving efficient methane conversion.

[0073] Example 6

[0074] Preparation of methane reforming composite catalyst

[0075] Hydrophilic fumed silica (A200, Evonik Degussa) was mixed with deionized water at a solid-liquid mass ratio of 5:100, and sonicated at 5 kPa for 10 min. The mixture was then stirred continuously at room temperature for 30 min. 100 mL of the suspension was collected. (The last part, "Ni," appears to be a continuation of the previous sentence and is left untranslated.) 2+ Ca 2+ In 3+ Al 3+ Prepare 80 mL of a quaternary mixed metal nitrate solution of nickel chloride, calcium chloride, indium chloride, and aluminum chloride in a molar ratio of 1.2:0.1:0.2:0.8, with a total molar concentration of 1.5 mol / L for the quaternary mixed metal ions. Slowly add the mixed metal salt solution to the suspension and stir continuously for 30 min. Quickly pour 0.18 mol of urea powder into the above mixed solution and stir continuously until the urea is fully dissolved. Then transfer it to a high-pressure reactor, seal it, and keep it at 200℃ for 18 h with stirring. After the temperature of the high-pressure reactor and the material inside the reactor drops to room temperature, open the reactor and collect the powdered solid product by vacuum filtration. Wash it repeatedly with deionized water 3-5 times and dry it at 105℃ to obtain the catalyst precursor. Calcine the catalyst precursor at 400℃ for 8 h to finally obtain the catalyst product.

[0076] Example 7

[0077] Methane reforming composite catalyst activation

[0078] 5g of the catalyst powder synthesized in Example 1 was evenly spread in a crucible and placed in the middle of the isothermal section of a tube furnace. The furnace was purged with N2 at a flow rate of 30 sccm for 30 min to remove air. Then, a mixture of 10 vol.% H2 and 90 vol.% N2 was introduced at a flow rate of 50 sccm, raising the temperature to 550°C at a rate of 5°C / min and holding at that temperature for 4 hours. After holding, the furnace was allowed to cool naturally to room temperature within the mixed gas atmosphere, thus completing catalyst activation.

[0079] Example 8

[0080] Preparation of methane reforming composite catalyst

[0081] Hydrophilic fumed silica (A200, Evonik Degussa) was mixed with deionized water at a solid-liquid mass ratio of 20:100, sonicated at 0.1 kPa for 30 min, and then stirred continuously at room temperature for 30 min. 100 mL of the suspension was then collected. (The last part, "Ni," appears to be a separate, unrelated sentence fragment and is left untranslated.) 2+ Ca 2 + In 3+ Al 3+ Prepare 150 mL of a quaternary mixed metal nitrate solution of nickel nitrate, calcium nitrate, indium nitrate, and aluminum nitrate in a molar ratio of 0.9:0.5:0.3:0.6, with a total molar concentration of 0.5 mol / L for the quaternary mixed metal ions. Slowly add the mixed metal salt solution to the suspension and stir continuously for 30 min. Quickly pour 0.75 mol of urea powder into the above mixed solution and stir continuously until the urea is fully dissolved. Then transfer it to a high-pressure reactor, seal it, and keep it at 150°C with stirring for 60 hr. After the temperature of the high-pressure reactor and the material inside the reactor drops to room temperature, open the reactor and collect the powdered solid product by vacuum filtration. Wash it repeatedly with deionized water 3-5 times and dry it at 105°C to obtain the catalyst precursor. Calcine the catalyst precursor at 600°C for 2 hr to finally obtain the catalyst product.

[0082] Example 9

[0083] Methane reforming composite catalyst activation

[0084] 5g of the catalyst powder synthesized in Example 1 was evenly spread in a crucible and placed in the middle of the isothermal section of a tube furnace. The furnace was purged with N2 at a flow rate of 30 sccm for 30 min to remove air. Then, a mixture of 5 vol.% H2 and 95 vol.% N2 was introduced at a flow rate of 50 sccm, raising the temperature to 600°C at a rate of 5°C / min and holding for 3 hours. After holding, the furnace was allowed to cool naturally to room temperature in the mixed gas atmosphere, thus completing catalyst activation.

[0085] Table 3. Composition of the synthesis catalysts in each embodiment.

[0086]

[0087] Comparative Example 1

[0088] Catalytic methane steam reforming performance

[0089] A commercially available catalyst (Z111-6 catalyst from the Southwest Institute) was crushed and sieved to obtain catalyst particles with an average particle size of 20–40 mesh. Two g of catalyst particles were taken and loaded into a fixed-bed reactor. In-situ reduction was carried out under atmospheric pressure using a mixture of 30 vol.% H2 and 70 vol.% N2 at a reduction temperature of 800℃ for 2 hours. After reduction, the furnace temperature was maintained at 800℃ and the pressure at atmospheric pressure. The reactor was purged with N2 for 15 minutes, followed by the introduction of CH4 and steam at a volume ratio of H2O:CH4 = 2:1 to initiate a steam reforming reaction (SMR) of methane.

[0090] The results showed that the reaction reached equilibrium after 1 hour, with a methane conversion rate of 98.6% and a hydrogen-to-carbon ratio of 5.0 in the product. However, after 100 hours of continuous operation, the methane conversion rate decreased to 90.3%, which was inferior to the catalyst of this invention.

[0091] Comparative Example 2

[0092] Catalytic performance of dry reforming of methane

[0093] Commercially available catalysts (Southwest Institute Z111-6 series catalysts) were crushed and sieved to obtain catalyst particles with an average particle size of 20-40 mesh. Two g of catalyst particles were taken and loaded into a fixed-bed reactor. In-situ reduction was carried out under atmospheric pressure using a mixture of 30 vol.% H2 and 70 vol.% N2 at a reduction temperature of 800℃ for 2 hours. After reduction, the furnace temperature was maintained at 800℃ and the pressure at atmospheric pressure, and the reactor was purged with N2 for 15 minutes. Subsequently, CH4 and CO2 were introduced at a CO2:CH4 volume ratio of 1:1 to carry out a dry methane reforming (DRM) reaction.

[0094] The results showed that the reaction reached equilibrium after 1 hour, with a methane conversion rate of 93.1% and a hydrogen-to-carbon ratio of 0.9 in the product. After 8 hours of continuous operation, the catalyst bed was blocked by carbon deposits, making it impossible to continue the experiment. Its performance was inferior to that of the catalyst of this invention.

[0095] Comparative Example 3

[0096] Catalytic methane co-reforming performance

[0097] Commercially available catalysts (Southwest Institute Z111-6 series catalysts) were crushed and sieved to obtain catalyst particles with an average particle size of 20-40 mesh. Two g of catalyst particles were taken and loaded into a fixed-bed reactor. In-situ reduction was carried out under atmospheric pressure using a mixture of 30 vol.% H2 and 70 vol.% N2 at 800℃ for 2 hours. After reduction, the furnace temperature was maintained at 800℃, and the reactor was purged with N2 for 15 minutes. Subsequently, CH4, CO2, and steam were introduced at a volume ratio of H2O:CO2:CH4 = 1:1:1 to carry out a combined methane reforming reaction (Bi-reforming).

[0098] At atmospheric pressure, the reaction reached equilibrium after 1 hour, with a methane conversion rate of 97.9% and a hydrogen-to-carbon ratio of 2.0 in the product. After 17 hours of continuous operation, the catalyst bed was blocked by carbon deposits, making it impossible to continue the experiment. Its performance was inferior to that of the catalyst of this invention.

[0099] When the pressure is increased to 2 MPa, the catalyst bed is blocked by carbon deposits after 40 minutes of reaction, making it impossible to continue the experiment. Its performance is inferior to that of the catalyst of this invention.

Claims

1. A methane reforming composite catalyst, characterized in that, The catalyst is an in-situ composite catalyst of a Ni-Ca-In-Al tetrametallic layered bimetallic hydroxide catalyst and a layered nickel silicate catalyst, which are combined with nickel as a medium. Its general chemical formula is: α[Ni i Ca j In k Al l [(OH)2](CO3) (k+l) / 2 ·βNi3Si4O 10 (OH)2; Among them, 0.6≤(α×i) / β≤6, i+j+k+l=1, and 0<i<1、0<j<1、0<k<1、0<l<1, and 0.2≤(i+j) / (k+l)≤1.

2.

2. A method for preparing the methane reforming composite catalyst according to claim 1, characterized in that, The method includes the following steps: S1: Mix silica with water to form a suspension M1; dissolve Ni salt, Ca salt, In salt and Al salt in water to prepare a quaternary mixed metal salt solution M2; S2: Add M2 to M1 to obtain a mixed solution M3; add urea and dissolve to obtain M4; S3: Transfer M4 to a high-pressure reactor, keep it warm, stir, cool it down, filter and collect the solid product, wash and dry it to obtain the catalyst precursor; S4: High-temperature calcination of the catalyst precursor yields the target catalyst product.

3. The preparation method according to claim 2, characterized in that, The silica in S1 is hydrophilic fumed silica; And / or, the processing in S1 is ultrasonic treatment under micro-negative pressure conditions; And / or, the quaternary mixed metal salts in S1 are salts with the same acid radical.

4. The preparation method according to claim 3, characterized in that, The mass ratio of silicon dioxide to water in S1 is 5~20:100; The pressure range of the slight negative pressure in S1 is 0.1~5 kPaA, and the ultrasonic treatment time is 10~30 min; The total molar concentration of metal ions in the quaternary mixed metal salt solution of S1 is 0.5~1.5 mol / L.

5. The preparation method according to claim 2, characterized in that, The volume ratio of M2 to M1 in S2 is 1.5:1 to 0.8:1; And / or, the amount of urea added to S2 is 1.5 to 5 times the total molar content of metal ions in M2.

6. The preparation method according to claim 2, characterized in that, The temperature of the high-pressure reactor in S3 is 150~200℃, and the holding time is 18~60hr.

7. The preparation method according to claim 2, characterized in that, The calcination temperature in S4 is 400~600℃, and the time is 2~8 hours.

8. Use of a composite catalyst, wherein the catalyst is the catalyst according to claim 1, or the catalyst prepared by any one of claims 2-7, characterized in that, The catalyst is used to catalyze methane reforming.

9. The use according to claim 8, characterized in that, The catalyst is now activated before it is used to catalyze methane reforming.

10. The use according to claim 9, characterized in that, The reducing gas in the activating medium is H2 and / or CO; The activation temperature is 550~800℃, and the activation time is 2~4 hours.

11. The use according to claim 10, characterized in that, The content of reducing gases is not less than 5 vol.%.

Images