Ni-based multi-element metal oxide, catalyst derived from Ni-based multi-element metal oxide, solid-phase preparation method of Ni-based multi-element metal oxide and application of Ni-based multi-element metal oxide in methane dry reforming reaction

Abstract

The invention provides a Ni-based multi-element metal oxide, a catalyst derived from the Ni-based multi-element metal oxide, a solid-phase preparation method and application of the Ni-based multi-element metal oxide in a methane dry reforming reaction. The Ni-based multi-element metal oxide is a rock salt phase and comprises Mg, Al and M, the M comprises one or more of Ca, Sr, Ba and Ga, the molar ratio of Mg to Al is 1-3, and the molar ratio of M to Al is 0.5-1.5; the mass fraction of Ni in the oxide is 5-20 wt%. The metal precursors are uniformly mixed by adopting a mechanical ball milling method, and the Ni-based multi-element metal oxide with a rock salt phase structure is obtained through high-temperature roasting. The Ni-based multi-element metal oxide is subjected to high-temperature reduction to obtain a derived catalyst, the loading capacity of active metal Ni in the catalyst is 4-16 wt%, the particle size of Ni is 10-15 nm, and the catalyst shows excellent activity and stability in a methane dry reforming reaction. The preparation process is simple and easy to repeatedly amplify; and no solvent participates, less wastewater is generated, and the method has a wide industrial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic material preparation, and particularly relates to a Ni-based multi-metal oxide, a catalyst derived therefrom, a solid-phase preparation method thereof, and an application in the dry reforming reaction of methane. Background Art

[0002] Converting methane into more valuable chemicals or fuels can not only reduce greenhouse gas emissions but also improve resource utilization efficiency. Therefore, how to efficiently convert methane to reduce its emissions and achieve resource utilization has become the focus of global scientific and industrial communities. Although the direct combustion of methane can release energy, it will produce a large amount of CO2, further exacerbating the greenhouse effect. In contrast, the chemical conversion technology of methane can convert it into high-value-added chemicals or clean energy, such as syngas (CO and H2), hydrogen (H2), etc., thus realizing the efficient utilization of resources and the reduction of greenhouse gas emissions. However, methane molecules have extremely high C-H bond energy (434 kJ / mol) and strong chemical inertness. Its conversion process usually requires high-temperature and high-pressure conditions, with high energy consumption and easy catalyst deactivation, which has become the main bottleneck for the efficient conversion of methane. Currently, methane conversion technologies are mainly divided into two approaches: direct conversion and indirect conversion. Direct conversion refers to directly converting methane into high-value-added chemicals such as methanol and formaldehyde. However, due to the chemical inertness of methane, this process usually requires harsh reaction conditions and low product selectivity, making it difficult to achieve industrial applications. Indirect conversion is to first convert methane into syngas and then prepare liquid fuels or chemicals through processes such as Fischer-Tropsch synthesis. Among them, the dry reforming of methane (DRM) technology has attracted much attention because it can simultaneously utilize two greenhouse gases, CH4 and CO2. The DRM technology generates syngas (CO and H2) through the reaction of CH4 and CO2, which can not only reduce greenhouse gas emissions but also provide important raw materials for the chemical industry. However, this technology still faces many challenges in practical applications: catalyst carbon deposition deactivation, high energy consumption, and difficulty in regulating the product ratio, which limit its subsequent applications.

[0003] Ni-based catalysts have the advantages of high activity and low cost in the dry reforming of methane (DRM) and are suitable for large-scale applications. However, they are prone to sintering and carbon deposition in the industrially common temperature range (500 °C to 800 °C), resulting in deactivation, which limits the industrial application of Ni-based catalysts. Therefore, designing Ni-based catalysts with high activity and high anti-carbon deposition performance is still a challenge at present. Summary of the Invention

[0004] In view of the above problems, the first object of the present invention is to provide a Ni-based multi-metal oxide in a rock salt phase, including Mg, Al and M, where M includes one or more of Ca, Sr, Ba and Ga, the molar ratio of Mg to Al is 1-3, and the molar ratio of M to Al is 0.5-1.5; the mass fraction of Ni in the oxide is 5-20 wt%.

[0005] The second object of the present invention is to provide a catalyst derived from the Ni-based multi-metal oxide, which is obtained by reducing the Ni-based multi-metal oxide. The loading amount of the active metal Ni in the catalyst is 4-16 wt%, and the particle size of Ni is 10-15 nm.

[0006] Preferably, the reduction atmosphere is H2, H2 / N2 or H2 / Ar, and the reduction time is 1-4 h. More preferably, the reduction atmosphere is 1-10 vol% H2 / N2 atmosphere.

[0007] The third object of the present invention is to provide a method for preparing the above Ni-based multi-metal oxide by a solid-phase method, including the following steps:

[0008] 1) Load each metal precursor into a ball milling jar, and perform cyclic mixing ball milling in an oscillating ball mill to obtain a solid powder; the ball milling frequency is 20-30 HZ, the ball milling time is 2-7 h, and the ball-to-material ratio is 10:1-40:1;

[0009] 2) Place the solid powder in a muffle furnace and calcine in air to obtain the Ni-based multi-metal oxide.

[0010] Preferably, the metal precursor is one or more of nitrates, chlorides, oxides and hydroxides, and more preferably one or two of hydroxides and oxides.

[0011] Preferably, a process control agent is added during ball milling, and the addition amount is 1-5 wt% of the total mass of the metal precursor.

[0012] Preferably, the control agent includes one or more of water, ethanol and stearic acid, and more preferably ethanol.

[0013] Preferably, the ball milling time is 2-4 h, and the ball-to-material ratio is 30:1-40:1.

[0014] Preferably, the calcination temperature is 600-800 °C, and the calcination time is 1-4 h; more preferably, the calcination time is 2-3 h.

[0015] The fourth object of the present invention is to provide an application of the catalyst in the dry reforming reaction of methane.

[0016] It includes the following steps: placing the catalyst in a fixed-bed reactor and introducing a mixed gas containing methane and carbon dioxide to carry out methane dry reforming reaction. The catalyst has excellent activity and good anti-coking performance.

[0017] Preferably, the reaction temperature is 600 - 800 °C, the reaction pressure is 0.1 - 2 Mpa, and the volumetric space velocity of the mixed gas is 200 - 300 Lg cat -1 h -1 , and the volume ratio of methane to carbon dioxide is 1:1 - 1:3.

[0018] Preferably, the concentration of the diluent gas in the mixed gas is 0 - 80 vol%, and more preferably 0 - 5 vol%.

[0019] Preferably, the diluent gas is nitrogen, argon or helium.

[0020] The beneficial effects of the present invention: The present invention uses mechanical ball milling method to uniformly mix metal precursors, and obtains Ni-based multi-metal oxides through high-temperature calcination. The mechanical ball milling method can improve the interaction of multi-component metal elements, obtain oxides with a single rock salt phase structure, and stabilize the active components to avoid metal sintering. The addition of Ca, Sr, Ba and Ga enhances the surface basicity of the catalyst, promotes the adsorption and activation of CO2, effectively reduces the coke generated in the reaction, and improves the anti-coking ability. Under the harsh reaction conditions of high space velocity, the catalyst maintains stable activity, the reaction deactivation rate in 100 h is only 1%, and the coking rate is only 0.000791 g·g cat -1 ·h -1 . The preparation process of the present invention is simple, easy to repeat and scale up; and there is no solvent involved, with less waste water, having broad industrial application prospects. Description of the Drawings

[0021] Figure 1 It is the EDX energy spectrum scanning diagram of the Ni-based multi-metal oxide prepared in Example 1.

[0022] Figure 2 It is the EDX energy spectrum scanning diagram of the Ni-based multi-metal oxide prepared in Comparative Example 1.

[0023] Figure 3 It is the XRD diagram of the oxides prepared in Examples 1, 3, 4, 6, 8, 11 and Comparative Examples 1 - 5.

[0024] Figure 4 It is the TEM diagram of the catalyst obtained after reducing the Ni-based multi-metal oxide prepared in Example 1 in an 800 °C, 10 vol% H2 / N2 atmosphere for 1 h.

[0025] Figure 5It is the thermogravimetric results of the catalysts prepared in Example 1 and Comparative Examples 1-5 after the catalytic reaction.

[0026] Figure 6 It is the activity diagram of the catalyst prepared in Example 1 for the 100 h stability test at 800 °C. Specific Embodiments

[0027] The following further illustrates the specific embodiments of the present invention in combination with the attached drawings and technical solutions.

[0028] Example 1

[0029] (1) Weigh 0.2897 g of Ni(OH)2, 0.5468 g of Mg(OH)2, 0.4875 g of Al(OH)3, 0.4631 g of Ca(OH)2 and 53.61 g of zirconia milling beads, place them in a zirconia milling jar, add 70 μL of absolute ethanol, and run at 25 HZ for 3 min and stop for 2 min. Mill for 2 h in an oscillating ball mill to obtain a solid powder;

[0030] (2) Place the above solid powder in a porcelain boat and calcine it in a muffle furnace at 800 °C in an air atmosphere for 2 h to obtain a Ni-based multi-metal oxide, denoted as (NiMgAlCa)O x . From Figure 1 it can be seen that the elements of the obtained oxide are evenly distributed. In addition, from the Figure 3 XRD results of (NiMgAlCa)O, it can be seen that the obtained oxide is a single rock salt phase structure. The TEM diagram of the catalyst obtained after reduction in a 10 vol% H2 / N2 atmosphere at 800 °C for 1 h is as shown in x , and the particle size of Ni is 10 - 15 nm. Figure 4 as shown

[0031] Example 2

[0032] The difference between this example and Example 1 is that the raw materials and dosages selected in step 1 are: 0.6058 g of Ni(NO3)2·6H2O, 1.6025 g of Mg(NO3)2·6H2O, 1.5630 g of Al(NO3)3·9H2O, 0.9840 g of Ca(NO3)2·4H2O and 47.55 g of zirconia milling beads. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -1.

[0033] Example 3

[0034] The difference between this example and Example 1 is that in Step 1, the raw materials and their dosages used are: 0.2318 g of Ni(OH)2, 0.4374 g of Mg(OH)2, 0.39 g of Al(OH)3, 0.5773 g of Ba(OH)2·8H2O, and 49.03 g of zirconia grinding beads. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlBa)O x 。

[0035] Example 4

[0036] The difference between this example and Example 1 is that in Step 1, the raw materials and their dosages used are: 0.2318 g of Ni(OH)2, 0.4374 g of Mg(OH)2, 0.39 g of Al(OH)3, 0.7189 g of Sr(OH)2·8H2O, and 53.24 g of zirconia grinding beads. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlSr)O x 。

[0037] Example 5

[0038] The difference between this example and Example 1 is that in Step 1, the raw materials and their dosages used are: 0.2318 g of Ni(OH)2, 0.4374 g of Mg(OH)2, 0.39 g of Al(OH)3, 0.5623 g of Ga2O3, and 48.66 g of zirconia grinding beads. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlGa)O x 。

[0039] Example 6

[0040] The difference between this example and Example 1 is that in Step 1, the molar ratio of Mg:Al used is 1 and the molar ratio of Ca:Al is 1.5. The specific dosages are: 0.2897 g of Ni(OH)2, 0.3645 g of Mg(OH)2, 0.4875 g of Al(OH)3, 0.6946 g of Ca(OH)2, and 55.09 g of zirconia grinding beads. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -2。

[0041] Example 7

[0042] The difference between this example and Example 1 is that in Step 1, the selected dosage is such that the molar ratio of Mg:Al is 2 and the molar ratio of Ca:Al is 0.5. The specific dosage is: 0.2897 g of Ni(OH)2, 0.729 g of Mg(OH)2, 0.4875 g of Al(OH)3, 0.2315 g of Ca(OH)2, and 52.13 g of zirconia milling beads. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -3

[0043] Example 8

[0044] The difference between this example and Example 1 is that the ball-to-material ratio is 10:1 and the ball milling time is 4 h. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -4

[0045] Example 9

[0046] The difference between this example and Example 1 is that the ball-to-material ratio is 10:1 and the ball milling time is 7 h. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -5

[0047] Example 10

[0048] The difference between this example and Example 1 is that the ball-to-material ratio is 10:1. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -6

[0049] Example 11

[0050] The difference between this example and Example 1 is that the ball-to-material ratio is 20:1. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -7

[0051] Example 12

[0052] The difference between this example and Example 1 is that the ball-to-material ratio is 40:1. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -8

[0053] Example 13

[0054] The difference between this example and Example 1 is that the process control agent is water. The remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -9

[0055] Example 14

[0056] The difference between this example and Example 1 is that the process control agent is stearic acid, and the remaining parameters and steps are the same as those in Example 1, denoted as (NiMgAlCa)O x -10

[0057] Comparative Example 1

[0058] Comparative sample (NiMgAlCa)O x -M preparation: Weigh 1.8174 g of Ni(NO3)2·6H2O, 4.8077 g of Mg(NO3)2·6H2O, 4.6891 g of Al(NO3)3·9H2O, and 2.9519 g of Ca(NO3)2·4H2O and dissolve them in 50 mL of deionized water to obtain a mixed metal salt solution A. Weigh 2.4 g of NaOH and 4.25 g of Na2CO3 and dissolve them in 50 mL of deionized water to obtain an alkali solution B. Add solution A to solution B at 30 °C and stir at a speed of 400 r. Titrate with 3M NaOH until the solution pH reaches ~10. Then transfer it to a 70 °C water bath for aging for 2 h, wash it with water until neutral, dry it at 80 °C for 24 h to obtain a solid powder. Roast the above powder in a muffle furnace at 800 °C for 2 h to obtain a mixed metal oxide. From Figure 2 It can be seen that the element distribution of the obtained material is uneven. At the same time, from Figure 3 It can be seen that in addition to the rock salt phase, there are other phases in the obtained material, such as calcium carbonate, etc.

[0059] Comparative Example 2

[0060] Comparative sample (NiMgAlMn)O x Preparation: The difference between this comparative example and Example 1 is that in step 1, the raw materials and their dosages used are: 0.2173 g of Ni(OH)2, 0.4101 g of Mg(OH)2, 0.3656 g of Al(OH)3, 0.4075 g of MnO2, and 42.13 g of zirconia grinding beads. The remaining parameters and steps are the same as those in Example 1. From Figure 3 It can be seen that phase separation exists in the prepared oxide.

[0061] Comparative Example 3

[0062] Comparative sample (NiMgAlCa)O x -0.5 preparation: The difference between this comparative example and Example 1 is that the ball milling time is 0.5 h, and the remaining parameters and steps are the same as those in Example 1. From Figure 3 It can be seen that phase separation exists in the prepared oxide.

[0063] Comparative Example 4

[0064] Comparative sample (NiMgAlCa)O x-5:1 Preparation: The difference between this comparative example and Example 1 is that the ball-to-material ratio is 5:1, and the remaining parameters and steps are the same as those in Example 1. It can be seen from Figure 3 that the prepared oxide has phase separation.

[0065] Comparative Example 5

[0066] Comparative sample (NiMg 0.5 Al1Ca2)O x Preparation: The difference between this example and Example 1 is that in Step 1, the selected dosage is a molar ratio of Mg:Al of 0.5 and a molar ratio of Ca:Al of 2. The specific dosage is: 0.2897 g of Ni(OH)2, 0.1823 g of Mg(OH)2, 0.4875 g of Al(OH)3, 0.9261 g of Ca(OH)2, and 56.56 g of zirconia milling beads. The remaining parameters and steps are the same as those in Example 1. It can be seen from Figure 3 that the prepared oxide has phase separation.

[0067] Test Example 1

[0068] Catalytic activity evaluation: The catalysts derived from the oxides prepared in Examples 1, 3 - 5 were subjected to activity tests. First, the above oxides were treated in an atmosphere of 0.1 Mpa, 800 °C, and 5 vol% H2 / N2 for 1 h. 25 mg of the reduced sample was weighed, mixed with 200 mg of quartz sand, and loaded into a quartz tube reactor. It was heated to 800 °C in an N2 atmosphere at 0.1 Mpa, and then the inlet gas was switched to CH4, CO2, N2 (CH4: 48 mL / min, CO2: 48 mL / min, N2: 4 mL / min), with a space velocity of 240 L / g cat h. After reacting for 10 h, the inlet gas was switched to N2, purged for 30 min, and then cooled to room temperature. The resulting gas passed through a cold trap and entered a gas chromatograph to analyze the product composition. The results are shown in Table 1. It can be seen that the prepared catalysts have good catalytic activity and stability, and the carbon deposition is not obvious after reacting for 10 h.

[0069] Table 1 Test conditions and conversion rates of the catalysts prepared in Examples 1, 3 - 5 for dry reforming of methane

[0070]

[0071] Test Example 2

[0072] Catalytic activity evaluation: The oxide-derived catalysts prepared in Examples 1-2, 6-14 were subjected to activity tests. First, the above materials were treated in an atmosphere of 0.1 Mpa, 800 °C, and 5 vol% H2 / N2 for 1 h. 25 mg of the reduced sample was weighed, mixed with 200 mg of quartz sand, loaded into a quartz tube reactor, heated to 800 °C in an N2 atmosphere at 0.1 Mpa, and then the inlet gas was switched to CH4, CO2, N2 (CH4: 48 mL / min, CO2: 48 mL / min, N2: 4 mL / min), with a space velocity of 240 L / g cat h. After reacting for 10 h, the inlet gas was switched to N2, purged for 30 min, and then cooled to room temperature. The resulting gas passed through a cold trap and entered a gas chromatograph to analyze the product composition. The results are shown in Table 2. All the catalysts showed high activity and stability. In Examples 8-9, the activity gradually increased with the extension of the ball milling time. In Examples 10-12, the activity gradually increased with the increase of the ball-to-material ratio, then tended to be stable and remained stable within 10 h.

[0073] Table 2 Test conditions and conversion rates of the catalysts prepared in Examples 1-2, 6-12 for dry reforming of methane

[0074]

[0075]

[0076] Test Example 3

[0077] Catalytic activity evaluation: The catalysts prepared in Example 1 and Comparative Examples 1-5 were subjected to activity tests. The parameters and procedures were the same as those in Test Example 1. The results are shown in Table 4. The thermogravimetric test results of the catalysts after the reaction are as Figure 5 shown. During the 10-h reaction process, the catalyst prepared in Example 1 maintained stable catalytic activity, and almost no carbon deposition was detected on the catalyst after the reaction. However, the conversion rate of the catalyst prepared in Comparative Example 1 continuously decreased during the 10-h reaction. The activity of the catalyst prepared in Comparative Example 2 continuously decreased during the test due to a large amount of carbon deposition, and there was a weight loss of up to 30% on the surface of the catalyst after the reaction. In Comparative Example 3, due to the short ball milling time, the catalyst was severely phase-separated, and the active components were not well activated, resulting in very low activity. In Comparative Example 4, due to the low ball-to-material ratio, the elements were not fully activated during the ball milling process, resulting in low interaction force between them and unable to stabilize the active components well. The sintering and growth of Ni during the high-temperature reaction process led to serious carbon deposition on the catalyst. In Comparative Example 5, due to the too high proportion of Ca element, the CaO in the catalyst was severely phase-separated, and the structure of the catalyst was prone to change during the reaction, resulting in a decrease in its activity and serious carbon deposition. Thus, it can be seen that in (NiMgAlCa)O xUnder this system, through ball milling for a certain period of time, the mechanical ball milling method can provide energy to achieve atomic-level uniform dispersion of elements in the catalyst, thereby obtaining a catalyst with a single rock salt phase structure. This structure stably exists during the reaction, while a large amount of calcium carbonate appears after the reaction of the catalyst prepared in Comparative Example 1, covering the active sites and leading to a continuous decline in activity. In addition, it can be seen from Comparative Example 2 that the addition of Ca can adsorb and activate CO2 and promote coke elimination.

[0078] Table 3 Catalytic Conditions and Performance of Methane Dry Reforming for the Catalysts in Example 1 and Comparative Examples 1-4

[0079]

[0080] Test Example 4

[0081] Catalytic Activity Evaluation: The catalyst prepared in Example 1 was subjected to activity tests with different raw gas ratios. Different from Test Example 1, the raw gas ratios were: CH4 / CO2 / N2 = 1 / 1 / 3, 1 / 2 / 2, and 1 / 3 / 1, and the other parameters and steps were the same as those in Test Example 1. The results are shown in Table 4.

[0082] Table 4 Test Conditions and Performance of Methane Dry Reforming for the Composite Material Prepared in Example 1 under Different Raw Gas Ratio Conditions

[0083] Sample Name <![CDATA[Raw gas composition (CH4 / CO2 / N2)]]> <![CDATA[CH4 conversion rate (%)]]> <![CDATA[CO2 conversion rate (%)]]> <![CDATA[(NiMgAlCa)O x > 1 / 1 / 3 88 90 <![CDATA[(NiMgAlCa)O x > 1 / 2 / 2 89 71 <![CDATA[(NiMgAlCa)O x > 1 / 3 / 1 89 54

[0084] Test Example 5

[0085] Catalytic Activity Evaluation: The catalyst prepared in Example 1 was subjected to activity tests at different reaction temperatures. Different from Test Example 1, the catalytic test temperatures were 600 °C, 700 °C, and 800 °C, and the other parameters and steps were the same as those in Test Example 1. The results are shown in Table 5.

[0086] Table 5 Test Conditions and Conversion Rates of Methane Dry Reforming for the Composite Material Prepared in Example 1 under Different Reaction Temperature Conditions

[0087] Sample Name Reaction Temperature (°C) <![CDATA[CH4 conversion rate (%)]]> <![CDATA[CO2 conversion rate (%)]]> <![CDATA[(NiMgAlCa)O x > 600 30 42 <![CDATA[(NiMgAlCa)O x > 700 58 65 <![CDATA[(NiMgAlCa)O x > 800 77 86

[0088] Test Example 6

[0089] Catalyst activity evaluation: The catalyst prepared in Example 1 was subjected to a long-term activity test. The catalyst obtained in Example 1 was treated in an atmosphere of 0.1 Mpa, 800 °C, and 5 vol% H2 / N2 for 1 h. 25 mg of the reduced sample was weighed, mixed with 200 mg of quartz sand, and loaded into a quartz tube reactor. It was heated to 800 °C in an N2 atmosphere at 0.1 Mpa, and then the inlet gas was switched to CH4, CO2, and N2 (CH4: 48 mL / min, CO2: 48 mL / min, N2: 4 mL / min), with a space velocity of 240 L / g cat h. After reacting for 10 h, the inlet gas was switched to N2. After purging for 30 min, the temperature was lowered to room temperature. The resulting gas passed through a cold trap and entered a gas chromatograph for product composition analysis. The carbon deposition amount of the catalyst after the reaction was tested by a thermogravimetric analyzer, and the carbon deposition rate was calculated based on the carbon deposition amount generated on the catalyst per unit time. As Figure 6 shown, the CH4 and CO2 conversion rates in the stability test were always stable at about 77% and 86%, respectively. After reacting for 100 h, the carbon deposition rate of the catalyst was 0.000791 g·g cat -1 ·h -1 .

[0090] The above are only the embodiments of the implementation of the present invention, and do not impose any formal restrictions on the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Ni-based multi-metal oxide, characterized in that: It is in the rock salt phase, including Mg, Al and M, where M includes one or more of Ca, Sr, Ba and Ga, the molar ratio of Mg to Al is 1 - 3, and the molar ratio of M to Al is 0.5 - 1.5; the mass fraction of Ni in the oxide is 5 - 20 wt%.

2. The catalyst derived from the Ni-based multi-metal oxide according to claim 1, characterized in that: It is obtained by reducing the Ni-based multi-metal oxide, the loading amount of the active metal Ni in the catalyst is 4 - 16 wt%, and the particle size of Ni is 10 - 15 nm.

3. A method for preparing the Ni-based multi-metal oxide according to claim 1 by a solid-phase method, characterized in that: It includes the following steps: 1) Load each metal precursor into a ball milling tank, and perform cyclic multiple mixing ball milling in an oscillating ball mill to obtain a solid powder; the ball milling frequency is 20 - 30 HZ, the ball milling time is 2 - 7 h, and the ball-to-material ratio is 10:1 - 40:1; 2) Place the solid powder in a muffle furnace and calcine it in air to obtain a Ni-based multi-metal oxide.

4. The method according to claim 3, wherein: The metal precursor is one or more of nitrate, chloride, oxide and hydroxide; and / or, The calcination temperature is 600 - 800 °C, and the calcination time is 1 - 4 h.

5. The method according to claim 1, wherein: A process control agent is added during ball milling, and the addition amount is 1 - 5 wt% of the total mass of the metal precursor.

6. The method according to claim 5, characterized in that: The control agent includes one or more of water, ethanol and stearic acid.

7. Application of the catalyst according to claim 2 in the dry reforming reaction of methane.

8. The application according to claim 7, characterized in that: The reaction temperature is 600 - 800 °C, the reaction pressure is 0.1 - 2 Mpa, and the mixed gas hourly space velocity is 200 - 300 Lg cat -1 h -1 , and the volume ratio of methane to carbon dioxide is 1:1 - 1:

3.

9. The application according to claim 7, characterized in that: The concentration of the diluent gas in the mixed gas is 0 - 80 vol%.

10. The application according to claim 7, wherein: The preferred concentration of the diluent gas in the mixed gas is 0 - 5 vol%.

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