Preparation method and application of high-activity porous reticular NiMeOx / Al-NA catalyst

Abstract

This invention discloses a method for preparing a highly active porous network NiMeOx / Al-NA catalyst and its application. In the catalyst, Me is a promoter metal selected from one or more of Cu, Y, and Ce. Al-NA is porous network nanoscale Al2O3. The catalyst preparation method includes: dissolving a template agent and an Al source in water and carrying out a hydrothermal reaction; then washing, drying, and grinding the mixture, followed by calcination in a muffle furnace to obtain porous network nanoscale Al2O3; using nanoscale Al2O3 as a support and water as a solvent, impregnating and loading a Ni source and a Me source, followed by drying, grinding, and calcination in a muffle furnace to complete the preparation. This invention enhances the catalyst's activity in methane steam reforming and its high-temperature resistance to sintering and carbon deposition, exhibiting excellent activity in the catalytic methane steam reforming reaction for hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of methane steam reforming for hydrogen production, specifically relating to a method for preparing and applying a highly active porous network NiMeOx / Al-NA catalyst. Background Technology

[0002] Steam reforming (SMR) of methane is currently the mainstream technology for industrial hydrogen production and an important pathway to realize the large-scale application of hydrogen energy. However, the SMR hydrogen production process suffers from problems such as high reaction temperature (800-1000℃) and high energy consumption, which severely restricts its application in distributed hydrogen production. In addition, existing Ni-based catalysts are prone to carbon deposition and sintering in high-temperature methane reforming reactions, leading to catalyst deactivation and limiting their application. Therefore, developing a novel nickel-based catalyst with high activity, anti-sintering properties, and excellent thermal stability has become a key technical challenge that urgently needs to be solved.

[0003] In recent years, researchers have improved the activity and anti-sintering ability of Ni-based catalysts from the perspectives of structural regulation and additive modification. Ding et al. prepared NiAl2O4 spinel catalysts using a co-precipitation method, which showed significantly higher nickel dispersion and oxygen vacancy concentration than Ni / γ-Al2O4 prepared by the traditional impregnation method, exhibiting better structural stability (International Journal of Hydrogen Energy, 2024, 51: 1256-1266). Han et al. introduced boron additives into Ni / MgAl2O4, which effectively improved nickel dispersion and inhibited carbon deposition (International Journal of Hydrogen Energy, 2024, 78:353-362). In addition, patent (CN118847130B) proposes using α-Al2O3 as a support to couple layered Ni active phase with CeO. x Nanoclusters were used to construct bifunctional catalysts with high resistance to carbon deposition. Although the above research has made progress in improving catalyst performance, significant shortcomings remain when considering distributed, dynamic operating scenarios (such as coupled solid oxide fuel cells): the catalytic activity of existing catalysts is still not ideal, and their tolerance to frequent thermal cycling, high-pressure steam oxidation, and complex impurities has not been systematically verified. Currently, catalyst systems possessing high activity, strong resistance to carbon deposition, and long-term thermal stability are still rarely reported.

[0004] To address this technological bottleneck, this invention proposes a novel strategy to develop a highly active nickel-based catalyst suitable for high-temperature methane steam reforming for hydrogen production. This catalyst possesses a unique interconnected porous nanostructure. By introducing a promoter metal, the dispersion of the active metal is promoted, resulting in excellent methane conversion. Furthermore, it promotes the formation of Ni-O-Al and Ni-O-Me active sites, enriching the electron-deficient Ni on the surface and enhancing CH bond activation and water molecule dissociation. Simultaneously, it enhances the catalyst's redox capacity and oxygen transfer, increases the specific surface area of ​​the oxide support, further promoting Ni dispersion on the oxide support. This significantly reduces the difficulty of water molecule decomposition into OH species and active hydrogen, improving catalyst activity and resistance to carbon deposition. This provides a new reforming catalyst design strategy and approach for advancing the development of distributed, low-carbon hydrogen energy systems. Summary of the Invention

[0005] In view of the above-mentioned technical problems existing in the prior art, the purpose of this invention is to provide a method for preparing a highly active porous network NiMeOx / Al-NA catalyst and its application.

[0006] A method for preparing a highly active porous network NiMeOx / Al-NA catalyst, wherein Me in the catalyst is a promoter metal selected from one or more of Cu, Y, and Ce, and Al-NA is a porous network nanoscale Al2O3. The preparation method includes the following steps: S1: At 20-40℃, with stirring, inject the template agent aqueous solution into the Al source aqueous solution at a uniform rate. After the addition is complete, continue to keep warm and stir for 0.5-2.0h to make the mixture uniform. S2: Transfer the mixture obtained in step S1 to a hydrothermal reactor lined with polytetrafluoroethylene. After sealing the hydrothermal reactor, place it in a forced-air drying oven and treat it at a high temperature of 150-200℃ for 48.0-120.0h. After treatment, remove the hydrothermal reactor and cool it to room temperature. Then, filter, wash, dry, and grind it. Calcine it in a muffle furnace at 700-850℃ for 1.0-4.0h to obtain porous network nanoscale Al2O3. S3: Using the nano-sized Al2O3 obtained in step S2 as a carrier and water as a solvent, impregnate and load Ni source and Me source; S4: After loading in step S3, the catalyst is dried, ground, and calcined in a muffle furnace at 600-750℃ for 1.0-5.0h to obtain a highly active porous network NiMeOx / Al-NA catalyst.

[0007] Further, in step S1, the template agent is glucose or urea, the Al source is at least one of aluminum nitrate and aluminum sulfate, and the molar ratio of the template agent to the Al source is 0.5-2:1, preferably 0.8-1.2:1.

[0008] Furthermore, in step S2, the temperature of the forced-air drying oven is 170-180℃, and the treatment time is 60-72h; after the treatment is completed, the hydrothermal reactor is taken out and placed at room temperature to cool for 12-15h.

[0009] Furthermore, in step S2, the calcination temperature in the muffle furnace is 750-800℃, and the calcination time is 2.0-3.0h.

[0010] Furthermore, in step S3, the Ni source and the Me source are at least one of metal nitrate and metal sulfate, respectively, and the molar amount of the Ni source is 5-30 times the molar amount of the Me source.

[0011] Furthermore, the total amount of Ni source and Me source is in the ratio of the mass of nanoscale Al2O3 support to 3-6 mmol:1g.

[0012] This invention also discloses the application of the aforementioned highly active porous network NiMeOx / Al-NA catalyst in the catalytic reaction of methane steam reforming to produce hydrogen.

[0013] Furthermore, before catalytic application, the catalyst also includes a step of heating and activating it in a mixed atmosphere of H2 and N2, wherein the volume ratio of H2 to N2 is 1:3-5, the heating and activation temperature is 500-800℃, preferably 600-650℃, and the heating and activation time is 1-6h.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The carrier preparation method provided by the present invention uses glucose as a template agent to form a highly dispersed porous network alumina. At the same time, the alumina particles have smaller particle size and higher specific surface area, which is beneficial to improving the dispersion of active components on its surface.

[0015] 2. The catalyst preparation method provided by this invention further promotes the dispersion of Ni on the alumina support by introducing auxiliary metals, and promotes the formation of Ni-O-Al and Ni-O-Me active sites, enriches the electron-deficient Ni sites on the surface, and strengthens the activation of CH bonds and the dissociation of water molecules at the interface between the active metal and the support; it enhances the redox ability of the catalyst, greatly reduces the difficulty of water molecules decomposing into OH species and active hydrogen, and strengthens the catalyst's methane steam reforming activity and high-temperature anti-sintering and anti-carbon deposition ability. Attached Figure Description

[0016] Figure 1 The X-ray crystal diffraction patterns are those of the catalysts prepared in Comparative Example 1 and Example 2. Figure 2 This is a transmission electron microscope (TEM) image of the catalyst prepared in Example 2.

[0017] Figure 3 This is a transmission electron microscope (TEM) image of the catalyst prepared in Comparative Example 1. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0019] Comparative Example 1: Synthesis using conventional Ni / Al2O3-TC catalyst 5.11 mmol of Ni(NO3)2·6H2O was dissolved in 9.8 mL of deionized water and ultrasonically dispersed. Then, 1.118 g of Al2O3 was added, and the mixture was stirred and impregnated at 40 °C and 800 rpm for 1.0 h. The mixture was then rotary evaporated to dryness at 60 °C and 90 rpm, and then dried in a 100 °C oven for 12.0 h. The dried sample was ground for 0.5 h and finally calcined in a muffle furnace at 650 °C for 3.0 h to obtain a conventional Ni / Al2O3 catalyst.

[0020] Example 1: Synthesis of a highly active porous network Ni / Al-NA catalyst

[0021] 133.3 mmol of Al(NO3)3·9H2O was dissolved in 100 mL of deionized water to form solution A, and 133.3 mmol of glucose was dissolved in 100 mL of deionized water to form solution B. Solution B was added to solution A at a rate of 2 mL / min, and stirring was continued for 1.0 h after the addition was complete. The mixed solution was transferred to a hydrothermal reactor and reacted at 180 °C for 72.0 h. After the reaction was completed, the mixture was cooled to room temperature, the resulting precipitate was filtered, and washed three times with deionized water. The solid was dried in an oven at 100 °C for 12.0 h, and then calcined in a muffle furnace at 800 °C for 3.0 h to obtain the support Al-NA. 5.11 mmol of Ni(NO3)2·6H2O was dissolved in 9.8 mL of deionized water, ultrasonically dispersed, and then 1.118 g of Al-NA support was added. The mixture was stirred and impregnated at 40 °C and 800 rpm for 1.0 h. The mixture was then rotary evaporated to dryness at 60℃ and 90 rpm, and then dried in an oven at 100℃ for 12.0 h. The dried sample was then ground for 0.5 h and finally calcined in a muffle furnace at 650℃ for 3.0 h. The resulting catalyst was named Ni / Al-NA.

[0022] Example 2: Highly active porous network NiCeO x Al-NA catalyst synthesis 133.3 mmol of Al(NO3)3·9H2O was dissolved in 100 mL of deionized water to form solution A, and 133.3 mmol of glucose was dissolved in 100 mL of deionized water to form solution B. Solution B was added to solution A at a rate of 2 mL / min, and stirring was continued for 1.0 h after the addition was complete. The mixed solution was transferred to a hydrothermal reactor and reacted at 180 °C for 72.0 h. After the reaction was completed, the mixture was cooled to room temperature, the resulting precipitate was filtered, and washed three times with deionized water. The solid was dried in an oven at 100 °C for 12.0 h, and then calcined in a muffle furnace at 800 °C for 3.0 h to obtain the support Al-NA. 4.60 mmol of Ni(NO3)2·6H2O and 0.51 mmol of Ce(NO3)3·6H2O were dissolved in 9.8 mL of deionized water, ultrasonically dispersed, and then 1.118 g of Al-NA support was added. The mixture was stirred and impregnated at 40 °C and 800 rpm for 1.0 h. The mixture was then rotary evaporated to dryness at 60℃ and 90 rpm, and then dried in a 100℃ oven for 12.0 h. The dried sample was then ground for 0.5 h and finally calcined in a muffle furnace at 650℃ for 3.0 h. The resulting catalyst was named NiCeO. x / Al-NA.

[0023] Figure 1 The X-ray diffraction patterns of the catalysts prepared in Comparative Example 1 and Example 2 are shown below. Figure 1 As can be seen from the above, the NiCeO prepared by this invention... x The presence of almost no characteristic diffraction peaks for CeO2 in the Al-NA catalyst indicates that Ce has been successfully doped into the alumina support, forming a highly dispersed solid solution structure. This promotes the formation of Ni-O-Al and Ni-O-Ce active sites, resulting in a richer supply of electron-deficient Ni on the surface, which can effectively promote the conversion of methane.

[0024] Figure 2 and Figure 3 The images show transmission electron microscopy (TEM) images of the catalysts prepared in Example 2 and Comparative Example 1, respectively. As can be seen from the images, compared to... Figure 3 Traditional Al2O3 in Figure 2 The Al-NA samples exhibited smaller alumina particles, only 7.84 ± 0.11 nm, and were uniformly distributed in a network structure, resulting in more pores or cavities. This increased the specific surface area of ​​the alumina, thereby improving the activity and stability of the catalyst.

[0025] Example 3: Highly active porous network NiCuO x Al-NA catalyst synthesis Example 3: The catalyst preparation steps were the same as in Example 2, except that Ce(NO3)3·6H2O was replaced with an equal molar amount of Cu(NO3)2·3H2O. All other conditions remained unchanged. The final catalyst was named NiCuO. x / Al-NA.

[0026] Example 4: Highly active porous network NiYO x Al-NA catalyst synthesis Example 4: The catalyst preparation steps were the same as in Example 2, except that Ce(NO3)3·6H2O was replaced with an equal molar amount of Y(NO3)3·6H2O. All other conditions remained unchanged. The final catalyst was named NiYO. x / Al-NA.

[0027] Example 5: NiCeO x Al-NA (urea) catalyst synthesis Example 5: The catalyst preparation steps were the same as in Example 2, except that glucose was replaced with an equal molar amount of urea. All other conditions remained unchanged. The final catalyst was named NiCeO. x / Al-NA (urea).

[0028] Example 6: Performance Evaluation of Methane Steam Reforming Catalyst for Hydrogen Production: Stability Test

[0029] A stainless steel tubular fixed-bed reactor with a quartz liner was used for the steam reforming of methane to produce hydrogen. The prepared catalyst was first pressed into tablets, then crushed, and screened to a size of 60-80 mesh. The catalyst particles were then loaded into the quartz liner of the stainless steel reaction tube. Quartz wool was used to fix the catalyst particles in the middle of the reaction tube, and then the tube was installed on the fixed-bed reactor. The fixed-bed pressure was adjusted to 3.0 MPa using nitrogen, and a leak test was performed. The pressure of the device did not drop significantly within 0.5 hours, indicating that the device was well sealed. After purging the high-pressure nitrogen, the nitrogen was replaced with a hydrogen-nitrogen mixture at atmospheric pressure. The hydrogen flow rate was adjusted to 20 mL / min and the nitrogen flow rate to 80 mL / min. The catalyst was activated by reduction at 650℃ for 2.0 h. After catalyst activation, the reactor was purged with a mixed gas (CH4:N2 = 1:1 by volume) for 30 min. The reaction temperature was 650℃, the deionized water feed flow rate was 0.089 mL / min, and the total space velocity (GHSV) of CH4, N2, and water vapor in the reaction was 15000 h⁻¹. -1 After the reaction reached steady state, the gaseous products were detected online using a multichannel gas chromatograph (F80) equipped with TCD and FID detectors.

[0030] Example 7: Performance evaluation of methane steam reforming catalyst for hydrogen production: tests at different temperatures

[0031] A stainless steel tubular fixed-bed reactor with a quartz liner was used for the steam reforming of methane to produce hydrogen. The prepared catalyst was first pressed into tablets, then crushed, and screened to a size of 60-80 mesh. The catalyst particles were then loaded into the quartz liner of the stainless steel reaction tube. Quartz wool was used to fix the catalyst particles in the middle of the reaction tube, and then the tube was installed on the fixed-bed reactor. The fixed-bed pressure was adjusted to 3.0 MPa using nitrogen, and a leak test was performed. The pressure of the device did not drop significantly within 0.5 hours, indicating that the device was well sealed. After purging the high-pressure nitrogen, the nitrogen was replaced with a hydrogen-nitrogen mixture at atmospheric pressure. The hydrogen flow rate was adjusted to 20 mL / min and the nitrogen flow rate to 80 mL / min. The catalyst was activated by reducing it at 650℃ for 2.0 h. After catalyst activation, the reactor was purged with a mixed gas (CH4:N2 = 1:1 by volume) for 30 min. The reaction temperature was 500-650℃, the deionized water flow rate was 0.089 mL / min, and the total space velocity (GHSV) of CH4, N2, and water vapor in the reaction was 15000 h⁻¹. -1 After the reaction reached steady state, the gaseous products were detected online using a multichannel gas chromatograph (F80) equipped with TCD and FID detectors.

[0032] Example 8: Performance evaluation of methane steam reforming catalyst for hydrogen production: Tests with different water-to-carbon ratios

[0033] A stainless steel tubular fixed-bed reactor with a quartz liner was used for the steam reforming of methane to produce hydrogen. The prepared catalyst was first pressed into tablets, then crushed, and screened to a size of 60-80 mesh. The catalyst particles were then loaded into the quartz liner of the stainless steel reaction tube. Quartz wool was used to fix the catalyst particles in the middle of the reaction tube, and then the tube was installed on the fixed-bed reactor. The fixed-bed pressure was adjusted to 3.0 MPa using nitrogen, and a leak test was performed. The pressure of the device did not drop significantly within 0.5 hours, indicating that the device was well sealed. After purging the high-pressure nitrogen, the nitrogen was replaced with a hydrogen-nitrogen mixture at atmospheric pressure. The hydrogen flow rate was adjusted to 20 mL / min and the nitrogen flow rate to 80 mL / min. The catalyst was activated by reduction at 650℃ for 2.0 h. After catalyst activation, the reactor was purged with a mixed gas (CH4:N2 = 1:1 by volume) for 30 min at a reaction temperature of 650℃. The flow rate of deionized water in the liquid phase feed was adjusted to 0.09-0.4 mL / min. The total space velocity (GHSV) of CH4, N2, and water vapor in the reaction was 15000 h⁻¹. -1 After the reaction reached steady state, the gaseous products were detected online using a multichannel gas chromatograph (F80) equipped with TCD and FID detectors.

[0034] Table 1 shows the catalytic evaluation results of the catalysts in Example 1 and Comparative Example 1 using a fixed-bed reactor. Reaction conditions: atmospheric pressure, temperature 650℃, gaseous feed composition (volume ratio CH4:N2) = 1:1, liquid feed deionized water, and the total space velocity (GHSV) of CH4-N2-water vapor was 15000 h⁻¹. -1 .

[0035] Table 1 Performance data of traditional Ni / Al2O3 and Ni / Al-NA catalysts .

[0036] As shown in Table 1, compared with the traditional Ni / Al2O3 catalyst, the catalyst prepared with Al-NA exhibits significantly improved activity: methane conversion increased by 29.3%, CO selectivity decreased by 3.5%, and the catalyst activity did not decrease significantly in the 100.0 h stability test. Furthermore, this application found in experiments that the catalyst in Comparative Example 1 showed a significant decrease in activity after 4.6 h of catalytic evaluation. This indicates that the Al-NA support prepared in this invention is beneficial for improving Ni dispersion, promoting the formation of Ni-O-Al active sites, enriching the electron-deficient Ni sites on the surface, and enhancing the methane steam reforming activity.

[0037] Table 2 shows the catalytic evaluation results of the catalysts in Examples 2-4 using a fixed-bed reactor. Reaction conditions: atmospheric pressure, temperature 650℃, gaseous feed composition (volume ratio CH4:N2) = 1:1, liquid feed deionized water, and a total space velocity (GHSV) of 15000 h⁻¹ for CH4, N2, and water vapor. -1 .

[0038] Table 2 NiMeO x Al-NA catalyst performance data .

[0039] As can be seen from the experimental results in Table 2, the doping of Ce, Cu and Y metals all effectively improved the CH4 conversion rate of the catalyst. Among them, Ce doping showed the most significant improvement, with a methane conversion rate as high as 90.3% and a CO selectivity reduced to 10.8%, demonstrating good methane conversion rate and CO selectivity.

[0040] Table 3 shows the catalytic evaluation results of the catalysts in Example 1 and Comparative Example 1 at different catalytic reaction temperatures using a fixed-bed reactor. Reaction conditions: atmospheric pressure, catalytic reaction temperature 500-700℃, gaseous feed volume ratio CH4:N2 = 1:1, liquid feed deionized water, and a total space velocity (GHSV) of 15000 h⁻¹ for CH4, N2, and water vapor. -1 As shown in Table 3, the conversion rate of CH4 increases with increasing reaction temperature, while the conversion rate of NiCeO2 increases.x The Al-NA catalyst exhibits significantly superior activity compared to the traditional Ni / Al2O3 catalyst (with improvements of 21%, 22%, 31.1%, 34.7%, and 28.9% at five temperature points: 500, 550, 600, 650, and 700 °C, respectively). This indicates that the prepared Al-NA support provides more active sites, and the introduction of Ce has a synergistic effect with Ni, enhancing the resistance to carbon deposition and promoting methane conversion.

[0041] Table 3 Traditional Ni / Al2O3 and NiCeO x Al-NA catalyst performance data .

[0042] Table 4 shows the catalytic evaluation results of the catalyst in Example 2 using a fixed-bed reactor at different water-to-carbon ratios. Reaction conditions: atmospheric pressure, temperature 650℃, gaseous feed composition (volume ratio CH4:N2) = 1:1, liquid feed deionized water, and a total space velocity (GHSV) of 15000 h⁻¹ for CH4, N2, and water vapor. -1 It can be seen that even when the water-to-carbon ratio decreases, NiCeO x The Al-NA catalyst still maintains an activity close to the equilibrium conversion, exhibiting good catalytic performance.

[0043] Table 4 NiCeO x Performance data of Al-NA catalysts with different water-to-carbon ratios .

[0044] Table 5 shows the catalytic evaluation results of the catalysts in Examples 2 and 5 using a fixed-bed reactor. Reaction conditions: atmospheric pressure, temperature 650℃, gaseous feed composition (volume ratio CH4:N2) = 1:1, liquid feed deionized water, and a total space velocity (GHSV) of 15000 h⁻¹ for CH4, N2, and water vapor. -1 It can be seen that NiCeO synthesized using urea as a template agent... x The activity of the Al-NA catalyst was significantly lower than that of the catalyst synthesized using glucose as a template.

[0045] Table 5 NiCeO x Performance data of Al-NA catalysts with different templates .

[0046] Table 6 shows the BET test data of the catalysts in Comparative Example 1 and Example 2 using a specific surface area and porosity analyzer. It can be seen that the NiCeO synthesized in this invention... x / Al-NA has a higher specific surface area, which effectively improves the activity and stability of the catalyst.

[0047] Table 6 .

[0048] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A method for preparing a highly active porous network NiMeOx / Al-NA catalyst, characterized in that, Me in the catalyst is a promoter metal, selected from one or more of Cu, Y, and Ce. Al-NA is a porous network nanoscale Al2O3. The preparation method includes the following steps: S1: At 20-40℃, with stirring, inject the template agent aqueous solution into the Al source aqueous solution at a uniform rate. After the addition is complete, continue to keep warm and stir for 0.5-2.0h to make the mixture uniform. S2: Transfer the mixture obtained in step S1 to a hydrothermal reactor lined with polytetrafluoroethylene. After sealing the hydrothermal reactor, place it in a forced-air drying oven and treat it at a high temperature of 150-200℃ for 48.0-120.0h. After treatment, remove the hydrothermal reactor and cool it to room temperature. Then, filter, wash, dry, and grind it. Calcine it in a muffle furnace at 700-850℃ for 1.0-4.0h to obtain porous network nanoscale Al2O3. S3: Using the nano-sized Al2O3 obtained in step 2 as a carrier and water as a solvent, impregnate and load Ni source and Me source; S4: After loading in step S3, the catalyst is dried, ground, and calcined in a muffle furnace at 600-750℃ for 1.0-5.0h to obtain a highly active porous network NiMeOx / Al-NA catalyst.

2. The method for preparing a highly active porous network NiMeOx / Al-NA catalyst as described in claim 1, characterized in that, In step S1, the template agent is glucose or urea, the Al source is at least one of aluminum nitrate and aluminum sulfate, and the molar ratio of the template agent to the Al source is 0.5-2:1, preferably 0.8-1.2:

1.

3. The method for preparing a highly active porous network NiMeOx / Al-NA catalyst as described in claim 1, characterized in that, In step S2, the temperature of the forced-air drying oven is 170-180℃, and the treatment time is 60-72h. After the treatment is completed, the hydrothermal reactor is taken out and placed at room temperature to cool for 12-15h.

4. The method for preparing a highly active porous network NiMeOx / Al-NA catalyst as described in claim 1, characterized in that, In step S2, the roasting temperature in the muffle furnace is 750-800℃, and the roasting time is 2.0-3.0h.

5. The method for preparing a highly active porous network NiMeOx / Al-NA catalyst as described in claim 1, characterized in that, In step S3, the Ni source and the Me source are at least one of metal nitrate and metal sulfate, respectively, and the molar amount of the Ni source is 5-30 times the molar amount of the Me source. The ratio of the total amount of Ni source and Me source to the mass of nanoscale Al2O3 support is 3-6 mmol:1g.

6. A highly active porous network NiMeOx / Al-NA catalyst prepared by the method described in any one of claims 1-5.

7. The application of the highly active porous network NiMeOx / Al-NA catalyst as described in claim 6 in the catalytic reaction of methane steam reforming to produce hydrogen.

8. The application as described in claim 7, characterized in that, Before catalytic application, the catalyst also includes a heating activation step in a mixed atmosphere of H2-N2, where the volume ratio of H2 to N2 is 1:3-5, the heating activation temperature is 500-800℃, preferably 600-650℃, and the heating activation time is 1-6h.

Images