阅读说明：本技术 一种碳化物改性Ni基有序介孔硅催化材料的制备方法及其应用 (Preparation method and application of carbide modified Ni-based ordered mesoporous silicon catalytic material ) 是由 石川 张晓� 刁亚南 刘洋 陈冰冰 于 2021-09-25 设计创作，主要内容包括：本发明公开了一种碳化物改性的Ni基有序介孔硅催化剂的制备方法及其应用。该等离子体-催化耦合反应过程及新型催化剂的应用可以有效解决传统甲烷-二氧化碳催化重整过程中存在的反应温度高、甲烷和二氧化碳转化率低、积碳严重及稳定性差等问题。所述制备方法,包括：钼酸铵-三聚氰胺杂化物的制备、碳化钼-有序介孔硅复合物的制备、Ni/MoC-(x)@OMSF催化剂的制备。本发明获得了一种三维有序介孔氧化硅分散Ni物种以及碳化钼物种的复合材料,具有更高的CH-(4)/CO-(2)转化率和更好的长效稳定性,以及更优异的能量效率,且催化剂制备工艺简单,易于实现工业化。(The invention discloses a preparation method and application of a carbide modified Ni-based ordered mesoporous silicon catalyst. The plasma-catalytic coupling reaction process and the application of the novel catalyst can effectively solve the problem of the traditional methane-dioxideThe problems of high reaction temperature, low conversion rate of methane and carbon dioxide, serious carbon deposition, poor stability and the like in the carbon catalytic reforming process. The preparation method comprises the following steps: preparation of ammonium molybdate-melamine hybrid, preparation of molybdenum carbide-ordered mesoporous silicon composite, and Ni/MoC x Preparation of the @ OMSF catalyst. The composite material of three-dimensional ordered mesoporous silicon oxide dispersed Ni species and molybdenum carbide species obtained by the invention has higher CH 4 /CO 2 The conversion rate, the long-acting stability and the energy efficiency are better, the preparation process of the catalyst is simple, and the industrialization is easy to realize.)

1. The preparation method of the carbide modified Ni-based ordered mesoporous silicon catalyst is characterized by comprising the following steps of:

1) preparation of ammonium molybdate-melamine hybrid: mixing an ammonium molybdate aqueous solution and a melamine aqueous solution at room temperature, aging for 2-5 hours to generate a white precipitate, and then carrying out suction filtration, washing and drying to obtain an ammonium molybdate-melamine hybrid;

wherein the concentration of the ammonium molybdate aqueous solution is 0.1-0.2mol/L, and the concentration of the melamine aqueous solution is 0.05-0.1 mol/L; the molar ratio of ammonium molybdate to melamine is 1:1-4: 1;

2) preparing a molybdenum carbide-ordered mesoporous silicon compound:

dissolving P123 in a hydrochloric acid solution, stirring in a water bath at 40-60 ℃ for 2-4 hours, adding the obtained ammonium molybdate-melamine hybrid, continuously stirring for 4-6 hours until the ammonium molybdate-melamine is completely dissolved, dripping tetraethoxysilane, continuously stirring for 5-10 hours, finally keeping the solution at 100-120 ℃ for 20-24 hours, and then performing suction filtration and drying to obtain a molybdenum carbide-ordered mesoporous silicon composite precursor; wherein the molar ratio of P123 to ammonium molybdate is 1-5: 1; the molar ratio of Si in the ethyl orthosilicate to Mo in the ammonium molybdate is 1-100: 1;

secondly, heating the obtained molybdenum carbide-ordered mesoporous silicon composite precursor to 600-fold temperature in hydrogen/inert gas mixed atmosphere or pure inert gas, keeping the temperature for 1 to 4 hours, cooling the sample to room temperature after roasting, and then adding 1 percent of O₂Passivating for 10-12h in a/Ar atmosphere to obtain a molybdenum carbide-ordered mesoporous silicon compound;

3) preparation of the carbide modified Ni-based ordered mesoporous silicon catalyst: and (2) taking the obtained molybdenum carbide-ordered mesoporous silicon composite as a carrier, preparing a metal nickel salt solution according to the mass percentage of Ni/(Ni + carrier) of 1-20%, mixing the metal nickel salt solution with the molybdenum carbide-ordered mesoporous silicon powder at room temperature by an impregnation method, continuously stirring for 1-2 hours, aging for 24-48 hours at room temperature, drying, and finally roasting for 1-4 hours at the temperature of 400-600 ℃ in an air atmosphere to obtain the carbide modified Ni-based ordered mesoporous silicon catalyst.

2. The preparation method according to claim 1, wherein in the step (II), the inert gas is one of nitrogen, argon or helium, the gas flow is 50-150mL/min, and the volume fraction of hydrogen in the mixed gas is 5-50%.

3. The method according to claim 1, wherein in step 3), the metallic nickel precursor salt is one of nickel nitrate, nickel acetate, nickel sulfate and nickel chloride.

4. The preparation method according to claim 1, wherein in step 1), the preparation method of the melamine aqueous solution comprises the following steps: dissolving melamine in deionized water, heating to 80-100 ℃, and stirring until the melamine is completely dissolved.

5. The method according to claim 1, wherein in step 1), the drying conditions are as follows: drying at 80-100 deg.C for 3-5 hr; in the step (i), the drying conditions are as follows: drying at 80-100 deg.C for 3-5 hr; in the step 3), the drying conditions are as follows: drying at 100-150 ℃ for 12-24 hours.

6. The application of the carbide modified Ni-based ordered mesoporous silicon catalyst obtained by the preparation method of any one of claims 1 to 5 in a plasma-catalytic coupling methane-carbon dioxide reforming reaction.

7. The use according to claim 6, wherein the plasma is generated by a dielectric barrier discharge, the input power of the plasma power supply is 20-500W, the center frequency is 2-50kHZ, the input voltage is 0.5-265V, and the input current is 0.1-2.5A.

8. Use according to claim 6, wherein the catalyst is used for plasma-catalytic coupling of CH₄-CO₂Before the reforming reaction, pretreatment is carried out, and the pretreatment method comprises the following steps: catalyst in pure H₂Pretreating for 1-4h at 400-600 ℃.

9. The use according to claim 6, wherein the reaction is carried out in a reactor made of ceramic, glass or quartz; the reactor has no additional heat source input.

10. Use according to claim 6, wherein the reaction pressure is atmospheric and the reaction gas is CH₄、CO₂Mixed gas with inert gas, wherein the volume percentage of the inert gas is 0-80%, and CH₄And CO₂The volume percentage of (1: 1) - (1: 4), and the reaction space velocity of 10,000-.

Technical Field

The invention relates to a plasma-catalyzed CH₄-CO₂A method for preparing synthesis gas by reforming, and preparation and application of a novel high-efficiency catalyst, belonging to CH₄-CO₂Reforming synthesis gas technology.

Background

Global demand and low-efficiency utilization of non-renewable energy sources such as petroleum and coal in human society have led to rapid depletion of fossil fuels and transitional emission of greenhouse gases. In view of the above, the human society jointly provides far-reaching targets of carbon peak reaching and carbon neutralization, and aims to construct a green low-carbon sustainable development ambitious blueprint. Methane and carbon dioxide are well known as two common greenhouse gases in atmospheric environments; in addition, with the discovery and exploitation of a large amount of resources such as shale gas and combustible ice, the activation conversion technology of methane also needs to be broken through urgently. Therefore, the realization of synchronous resource utilization of methane and carbon dioxide is crucial to the transformation of energy structures and the reduction of greenhouse effect caused by climate change.

The methane and carbon dioxide reforming for preparing the synthesis gas (DRM) is a hotspot and a difficulty of research in recent decades, and has the significance that (1) natural gas resources can be fully utilized, the energy crisis is relieved, and economic sustainable development is realized; (2) the emission of greenhouse gases is reduced, the global warming is relieved, and the environmental protection is facilitated; (3) h₂The ratio of/CO is more suitable for F-T synthesis and methanol synthesis; (4) methane carbon dioxide reforming can be used as an energy storage medium. The reaction provides a comprehensive utilization of carbon source and hydrogen source, simultaneously converts two kinds of small molecules which are difficult to activate, and eliminates two kinds of main greenhouse gasesThe technical route of the body has multiple research values of economy, environmental protection and science. However, the synthesis gas produced by reforming methane with carbon dioxide has not been really applied industrially, and one important reason is that the methane-carbon dioxide reforming reaction is a strong endothermic reaction (Δ H)_298K247.3kJ/mol), it must be carried out at high temperatures. The high temperature is carried out to increase the possibility of thermodynamically generating carbon deposit, which is easily deactivated by the catalyst, particularly the non-noble metal-Ni based catalyst. Although noble metal catalysts exhibit good resistance to carbon deposition and stability, noble metal catalysts are expensive and require recycling, limiting their industrial application. Therefore, it becomes important to select a catalyst that can kinetically suppress the generation of carbon deposit and at the same time accelerate the reaction rate of the methane carbon dioxide reforming reaction; in addition to this, the economics of the conversion process require improvements in methane-carbon dioxide reforming conversion technology.

For dry reforming reaction of methane, besides innovative modification of the catalyst, effective catalytic process development is also very important. The key of the new process is to search an advanced catalytic system to realize effective activation of C-H in a controllable reaction kinetic process and couple the action of an external field to effectively convert heat energy, electric energy, light energy and the like into driving force for activating C-H bonds. Due to the low temperature activation of non-equilibrium plasma to convert reactive molecules, which is a means of promoting chemical reactions, many chemical reactions that are difficult to perform under conventional conditions can be accomplished. However, the chemical reaction directly initiated by plasma generally has the problems of poor directional conversion capability of reactants to target products and low selectivity. Combining non-equilibrium plasma technology with catalytic processes, CH₄/CO₂Plasma catalytic reforming has received much attention in recent years from researchers as a potential methane reforming technology. However, the application of the catalyst to CH in conjunction with the cold plasma₄/CO₂The reforming process still has the defects of low reaction conversion rate, complex product types, low selectivity of target products, serious carbon deposition and the like. Therefore, a high-efficiency catalytic material is created and is efficiently coupled with cold plasma to be applied to CH₄/CO₂The reforming process can change the catalytic reaction process fundamentally, realize the high-efficiency activation and conversion of methane and carbon dioxide molecules under mild conditions, and enable energy micromolecules to directionally generate fuel or chemicals with high added value.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention aims to provide a preparation method of a novel high-efficiency carbide modified Ni-based ordered mesoporous silicon catalyst and application of the catalyst in a plasma-catalytic coupling methane-carbon dioxide catalytic reforming reaction process. The plasma-catalytic coupling reaction process and the application of the novel catalyst can effectively solve the problems of high reaction temperature, low conversion rate of methane and carbon dioxide, serious carbon deposition, poor stability and the like in the traditional methane-carbon dioxide catalytic reforming process. In order to solve the above technical problems, the present invention is implemented by the following technical solutions.

A preparation method of a novel high-efficiency carbide modified Ni-based ordered mesoporous silicon catalyst comprises the following steps:

1) preparation of ammonium molybdate-melamine hybrid: mixing ammonium molybdate (AHM) aqueous solution with melamine (C)₃H₆N₆MA) aqueous solution is mixed at room temperature, aged for 2-5 hours to generate white precipitate, and then the white precipitate is filtered, washed and dried to obtain ammonium molybdate-melamine hybrid which is marked as AHM-MA;

wherein the concentration of the ammonium molybdate aqueous solution is 0.1-0.2mol/L, and the concentration of the melamine aqueous solution is 0.05-0.1 mol/L; the molar ratio of ammonium molybdate to melamine is 1:1 to 4: 1.

Preferably, in the above technical solution, in step 1), the preparation method of the melamine aqueous solution comprises: mixing melamine (C)₃H₆N₆MA) is dissolved in deionized water, heated to 80-100 ℃, and stirred vigorously at the temperature until the melamine is completely dissolved.

Preferably, in the above technical solution, in step 1), the drying conditions are: drying at 80-100 deg.C for 3-5 hr.

2) Preparing a molybdenum carbide-ordered mesoporous silicon compound:

dissolving a certain amount of P123 in a hydrochloric acid solution, stirring for 2-4 hours in a constant-temperature water bath at 40-60 ℃, then adding a certain amount of the obtained ammonium molybdate-melamine (AHM-MA) hybrid, continuously stirring for 4-6 hours until the AHM-MA is completely dissolved, dripping a target amount of tetraethoxysilane, continuously stirring for 5-10 hours, finally transferring the solution into a hydrothermal kettle, keeping the solution at the temperature of 100 ℃ and 120 ℃ for 20-24 hours, and then carrying out suction filtration and drying to obtain the molybdenum carbide-ordered mesoporous silicon composite precursor.

Wherein the molar ratio of P123 to ammonium molybdate is 1-5: 1; the concentration of the hydrochloric acid solution is 1.0-2.5M; the change range of the molar ratio of Si in the ethyl orthosilicate to Mo in the ammonium molybdate is 1-100: 1, changing the addition of the AHM-MA hybrid to obtain the molybdenum carbide-ordered mesoporous silicon composite precursor with different Si/Mo molar ratios.

Preferably, in the above technical solution, in step (i), the drying conditions are: drying at 80-100 deg.C for 3-5 hr.

Secondly, placing the obtained molybdenum carbide-ordered mesoporous silicon compound precursor in a tubular furnace, heating to 600-700 ℃ in the mixed atmosphere of hydrogen and inert gas or pure inert gas, and keeping for 1-4 hours; after calcination the sample was cooled to room temperature and then at 1% O₂Passivating for 10-12h in a/Ar atmosphere to obtain a molybdenum carbide-ordered mesoporous silicon compound, and marking a sample as MoC_x@OMSF；

Preferably, in the above technical solution, in the step (ii), the inert gas is one of nitrogen, argon or helium, the gas flow rate is 50-150mL/min, and the volume fraction of hydrogen in the mixed gas is 5-50%.

3) Carbide modified Ni-based ordered mesoporous silicon (Ni/MoC)_x@ OMSF) preparation of catalyst: preparing a metal nickel salt solution containing a target amount by taking the obtained molybdenum carbide-ordered mesoporous silicon composite as a carrier and according to the mass percentage of Ni/(Ni + carrier) of 1-20%, mixing the metal nickel salt solution and the molybdenum carbide-ordered mesoporous silicon composite powder at room temperature by an impregnation method, continuously stirring for 1-2 hours, aging for 24-48 hours at room temperature, fully drying, roasting at 400-600 ℃ for 2-4 hours in the air atmosphere of a muffle furnace, and cooling to obtain Ni/MoC_x@ OMSF catalyst.

Preferably, in the above technical solution, in step 3), the drying conditions are: drying at 100-150 ℃ for 12-24 hours.

Preferably, in the above technical solution, in step 3), the metallic nickel precursor salt is one of nickel nitrate, nickel acetate, nickel sulfate, and nickel chloride.

Preferably, in the above technical solution, in step 3), the impregnation method is an equal-volume impregnation method.

The invention also aims to provide the novel high-efficiency carbide modified Ni-based ordered mesoporous silicon catalyst as a catalyst, which is prepared by coupling low-temperature plasma-catalysis with CH₄-CO₂Application in reforming reaction process.

The catalyst is placed in a non-equilibrium plasma generator, the mixed gas of methane and carbon dioxide is discharged in atmospheric pressure plasma, and efficient methane-carbon dioxide plasma catalytic reforming is realized under the synergistic action of the non-equilibrium plasma and the catalyst.

Preferably, in the technical scheme, the dosage of the catalyst is 10-400 mg.

Preferably, in the technical scheme, the catalyst is coupled with CH in a low-temperature plasma-catalysis mode₄-CO₂Before the reforming reaction, pretreatment is carried out, and the pretreatment method comprises the following steps: catalyst in pure H₂Pretreating for 1-4h at 400-600 ℃.

Preferably, in the above technical solution, the reaction atmosphere is CH₄And CO₂Mixed gas or CH₄、CO₂The reaction pressure of the mixed gas and inert gas is normal pressure, wherein the volume percentage of the inert gas is 0-80%.

Preferably, in the above technical solution, the CH₄And CO₂The volume ratio of the gas is 1: 1-1: 4.

Preferably, in the above technical solution, the non-thermal plasma introduction manner is Dielectric Barrier (DBD) discharge, and the input power of the low-temperature plasma power supply is 20-500W, preferably 20-200W; the central frequency is 2-50kHZ, and preferably 2-30 kHz; the applied input voltage is 0.5-265V, preferably 20-50V; the input current is 0.1-2.5A, preferably 0.5-2A.

Preferably, in the technical scheme, the mass space velocity of the reaction in the plasma-catalytic coupling reaction is 10,000-1,500,000mL/g/h, and preferably 10,000-500,000 mL/g/h.

Preferably, in the above technical solution, the reaction is performed in a reactor, and the material of the reactor is ceramic, glass or quartz; the reactor has no additional heat source input.

The invention has the advantages that:

1. compared with the traditional supported nickel-based catalyst, the composite material of the three-dimensional ordered mesoporous silicon oxide dispersed Ni species and molybdenum carbide species is obtained, the embedded carbide is highly attached to the inner wall of a mesoporous silicon oxide pore channel, and has stronger interaction with the Ni species, so that the dispersibility of active metal Ni is greatly improved, more than 90% of Ni species are encapsulated in the mesoporous silicon oxide regular pore channel, and the strong interaction and the encapsulation effect of the pore channel can effectively inhibit the agglomeration and sintering of metal Ni particles;

2. the invention obtains a novel bifunctional composite Ni/MoC_x@ OMSF catalytic Material, active Ni species effective to activate dissociated methane, MoC_xSpecies can effectively activate CO₂The high dispersion property of the Ni and the MoC effectively increases the Ni-MoC composite active interface and obviously improves CH₄And CO₂The rate of activation of the molecule; meanwhile, the Ni-MoC action interface is encapsulated in the regular pore channel of the mesoporous silicon oxide material, effectively plays the role of a 'microreactor' in the reaction process, and is beneficial to improving the surface interface adsorption and desorption properties and catalytic performance of the catalyst;

3. compared with the traditional supported nickel-based catalyst, the three-dimensional ordered mesoporous silica supported Ni-MoC obtained by the invention_xThe composite material has higher CH₄/CO₂The conversion rate, the long-acting stability and the energy efficiency are better, the preparation process of the catalyst is simple, and the industrialization is easy to realize. Wherein the activity is bestIs MoC_xNi/MoC with the mass percent of 20 wt% and the mass percent of metal Ni of 10 wt%_xThe @ OMSF catalytic material obtains CH higher than 90% in a plasma-catalytic coupling reaction mode without an external heating source₄And CO₂Conversion rate, no obvious inactivation phenomenon in a stability test period of 100 hours, and maximum energy efficiency values of 64 percent and 3.3 mmol/kJ.

Drawings

The invention is illustrated in figure 5:

FIG. 1 shows the Ni/MoC obtained in example 1_x@ OMSF catalyst, conventional Supported Ni/SiO catalyst from comparative example 1₂XRD contrast patterns of the catalyst and the Ni/OMSF catalyst obtained in comparative example 2;

FIG. 2 shows the Ni/MoC obtained in example 1_xA high resolution transmission electron micrograph of @ OMSF catalyst;

FIG. 3 shows the Ni/MoC obtained in example 1_x@ OMSF catalyst, conventional Supported Ni/SiO catalyst from comparative example 1₂Plasma-catalytic coupling of catalyst and Ni/OMSF catalyst from comparative example 2 to CH₄-CO₂A graph comparing catalytic performance in reforming reactions;

FIG. 4 shows the Ni/MoC obtained in example 1_x@ OMSF catalyst, conventional Supported Ni/SiO catalyst from comparative example 1₂Application of catalyst and Ni/OMSF catalyst obtained in comparative example 2 to plasma-catalytic coupling of CH₄-CO₂XRD contrast diagram after reforming reaction;

FIG. 5 shows the Ni/MoC obtained in example 1_x@ OMSF catalyst in plasma-catalytic coupling of CH₄-CO₂Stability evaluation in reforming reactions.

Detailed Description

The following non-limiting examples will allow one of ordinary skill in the art to more fully understand the present invention, but are not intended to limit the invention in any way.

Example 1

Preparing a catalyst:

1) preparation of ammonium molybdate-melamine hybrid: 1g of ammonium molybdate (AHM) was dissolved in 25mL of deionized water at room temperature to obtain an aqueous solution of ammonium molybdateAnd (4) liquid. 1g of melamine (C)₃H₆N₆In short: MA) adding 100mL of deionized water, heating to 80 ℃, stirring vigorously until the melamine is completely dissolved, and stopping stirring to obtain the melamine aqueous solution. After the two solutions are naturally cooled to room temperature, the two solutions are mixed, and a white precipitate is generated immediately. Mixing, standing for 2h, suction filtering, washing with water to obtain white precipitate, and drying the white solid at 80 deg.C for 3h to obtain ammonium molybdate-melamine hybrid, which is marked as AHM-MA.

2) Preparing a molybdenum carbide-ordered mesoporous silicon compound: dissolving 2g P123 in 50mL of hydrochloric acid (2.5M), stirring for 1h in a water bath at the constant temperature of 40 ℃, adding 22g of AHM-MA hybrid, stirring for 5h, dripping 5.82g of tetraethoxysilane after the AHM-MA is completely dissolved, continuing stirring for 5h, transferring the solution to a 100mL hydrothermal kettle, and keeping the temperature of 100 ℃ for 24 h. And (3) carrying out suction filtration, directly obtaining light blue solid without cleaning, and drying at 120 ℃ for 6h to obtain the molybdenum carbide-ordered mesoporous silicon composite precursor. ② putting the molybdenum carbide-ordered mesoporous silicon compound precursor into a tube furnace, and putting the precursor into a tube furnace in H₂Heating to 650 ℃ at a speed of 5K/min under a mixed atmosphere of/Ar (70mL/min, v: v ═ 2:5), keeping the temperature for 90min, closing the gas when the temperature is reduced to 300 ℃, and enabling the air to diffuse into the tube along the air outlet pipe to slowly passivate the sample so as to avoid deep oxidation of the sample when the sample is exposed to the air, thereby obtaining molybdenum carbide-ordered mesoporous silicon composite powder, wherein the sample is marked as MoC_x@OMSF-6。

3) Preparation of Ni/MoCx @ OMSF catalyst: taking the obtained molybdenum carbide-ordered mesoporous silicon composite powder material as a carrier, and mixing the molybdenum carbide-ordered mesoporous silicon composite powder material with Ni: preparing a metal nickel salt solution containing 0.35g of nickel nitrate with the mass percent of (Ni + carrier) being 10%, mixing the metal nickel salt solution with carrier powder at room temperature by an equal-volume impregnation method, continuously stirring for 2 hours, aging for 24 hours at room temperature, drying for 12 hours at 100 ℃, roasting for 4 hours at 500 ℃ in a muffle furnace air atmosphere, and cooling to obtain Ni/MoC_x@ OMSF Material, where the Carrier absorbs 4.1mL of water_H2O/g_Carrier. As shown in the figure 1 and the figure 2, the Ni/MoCx @ OMSF material has the Ni grain size of about 5nm, and more than 90 percent of Ni species are encapsulated in the mesoporous silica regular pore channels.

Evaluation of catalyst Performance:

the plasma-catalytic coupling methane-carbon dioxide reforming reaction is carried out in a Dielectric Barrier Discharge (DBD) fixed bed reactor. The DBD reactor is a quartz reaction tube with the inner diameter of 8mm and the wall thickness of 1mm, and the length of a discharge interval is 10 mm. 60mg of the above catalyst (Ni/MoCx @ OMSF material) and 340mg of inert SiO were weighed out₂Mixing and placing in a reactor, and fixing the upper end and the lower end by high-temperature quartz wool. A stainless steel bar with the diameter of 2mm is inserted into the center of the quartz tube to serve as a high-voltage electrode, a stainless steel mesh is wrapped on the outer wall of the reaction tube to serve as a ground electrode, and plasma is generated through dielectric barrier discharge. The input voltage of the low-temperature plasma generator is 50V, the current is 0.95A, the input power is 47.5W, and the working center frequency is 30 kHZ. The catalyst was first purified at 100mL/min of pure H₂Pretreating for 2h at 500 ℃ in atmosphere, and then introducing CH₄/CO₂Under the mixed atmosphere of/Ar (v/v/v is 3/3/2), the mass space velocity is 100,000mL/g/h, tail gas is detected by GC, and CH is calculated₄&CO₂And (4) conversion rate. As shown in FIG. 3, Ni/MoC under room temperature discharge without external heat source_x@ OMSF catalyst, yielding over 90% CH₄Conversion and over 80% CO₂The conversion rate is close to the reaction time of 40h, the reaction activity is basically kept unchanged, and the maximum energy efficiency can reach 3.3 mmol/kJ. The XRD pattern after reaction showed (as shown in fig. 4) that the catalyst surface was substantially free of carbon deposition. Meanwhile, as shown in FIG. 5, long-acting stability test experiments show that the catalyst has CH within the reaction time of 100h₄And CO₂The conversion rate is always higher than 90%, no obvious deactivation phenomenon exists, and the maximum energy efficiency value reaches 64% and 3.3 mmol/kJ.

Comparative example 1

Preparing a catalyst:

first, commercial SiO was measured₂The water absorption of the powder was 1.4ml_H2O/g_SiO2. According to the weight ratio of Ni: (Ni + SiO)₂) Weighing 2gSiO in 10 wt%₂Powder samples and 0.35g of nickel nitrate, then according to commercial SiO₂The water absorption of the powder is prepared by dissolving the nickel nitrate in 2.8ml of deionized water by an isometric immersion method to prepare a solution, and the Ni salt solution is addedAnd commercial SiO₂Mixing the powders at room temperature, stirring with glass rod for 1 hr, aging at room temperature for 24 hr, drying at 110 deg.C for 12 hr, calcining at 500 deg.C in air atmosphere of muffle furnace for 4 hr, cooling, and grinding to obtain 10% Ni/SiO₂A catalyst. As shown in FIG. 1, Ni/SiO₂The Ni grain size in the material is about 13 nm.

Evaluation of catalyst Performance:

plasma-catalytic coupled methane-carbon dioxide reforming reaction performance was tested in the reactor described in example 1 above, with the same discharge conditions as in example 1. 60mg of the above catalyst (10% Ni/SiO) was weighed₂Catalyst) and 340mg of inert SiO₂Mixing and placing in a reactor, the catalyst is firstly pure H with the concentration of 100mL/min₂Pretreating for 2h at 500 ℃ in atmosphere, and then introducing CH₄/CO₂The mass space velocity of the mixed atmosphere of/Ar (v/v is 3/3/2) is 100,000mL/g/h, tail gas is detected by GC, and CH is calculated₄&CO₂And (4) conversion rate. As shown in FIG. 3, Ni/SiO solid phase discharge was performed under room temperature discharge without an external heat source₂Catalyst initial CH₄And CO₂The conversion rates were 80% and 70%, respectively, and after 5 hours of reaction, CH₄And CO₂The conversion rate is respectively reduced to 30 percent and 28 percent, and the energy efficiency can reach 0.7 mmol/kJ.

Comparative example 2

Preparing a catalyst:

firstly, the water absorption of the self-made pure ordered mesoporous silicon carrier is measured to be 4.3ml_H2O/g_OMSF. The specific preparation process of the pure ordered mesoporous silicon support (OMSF) is similar to the step 2 of the catalyst preparation process in example 1, except that no AHM-MA hybrid is added. Then, according to the Ni: weighing 2g of carrier powder sample and 0.35g of nickel nitrate according to the mass percent of (Ni + OMSF) being 10 percent, then dissolving the nickel nitrate in 2.8ml of deionized water by adopting an equal-volume immersion method according to the water absorption rate of the OMSF powder to prepare a solution, mixing the Ni salt solution and the commercial OMSF powder at room temperature, continuously stirring the mixture for 1 to 2 hours by using a glass rod, aging the mixture for 24 hours at room temperature, drying the mixture for 12 to 24 hours at the temperature of 100 plus 150 ℃, and finally roasting the mixture in the atmosphere of air in a muffle furnace at the temperature of 500 DEG CAfter 4 hours, cooling and grinding, 10% Ni/OMSF catalyst was obtained. As shown in FIG. 1, the Ni/OMSF material has a Ni particle size of about 6.3 nm.

Evaluation of catalyst Performance:

plasma-catalytic coupled methane-carbon dioxide reforming reaction performance was tested in the reactor described in example 1 above, with the same discharge conditions as in example 1. 60mg of the above catalyst (10% Ni/OMSF catalyst) and 340mg of inert SiO were weighed out₂Mixing and placing in a reactor, the catalyst is firstly pure H with the concentration of 100mL/min₂Pretreating for 2h at 500 ℃ in atmosphere, and then introducing CH₄/CO₂The mass space velocity of the mixed atmosphere of/Ar (v/v is 3/3/2) is 100,000mL/g/h, tail gas is detected by GC, and CH is calculated₄&CO₂And (4) conversion rate. As shown in FIG. 3, the initial CH of Ni/OMSF catalyst is determined under room temperature discharge without external heat source₄And CO₂The conversion rates were 92% and 80%, respectively, after 20 hours of reaction, CH₄And CO₂The conversion rates are respectively reduced to 61 percent and 58 percent, and the energy efficiency can reach 2.0 mmol/kJ. The XRD pattern after reaction (as shown in fig. 4) shows that there is significant carbon deposition on the surface of the catalyst.

Example 2

The procedure and process conditions of this example were the same as those of example 1 except that 2.2g of AHM-MA hybrid precursor was weighed and added to the mixed solution, followed by the same preparation process to obtain Ni/MoC_x@ OMSF-60 catalyst. ② the activity evaluation is carried out on the catalyst, the catalyst is initial CH₄And CO₂The conversions were 85% and 75%, respectively, and the maximum energy efficiency value was 2.5 mmol/kJ.

Example 3

The procedure and process conditions of this example were the same as those of example 1 except that 11g of AHM-MA hybrid precursor was weighed and added to the mixed solution, followed by the same preparation process to obtain Ni/MoC_x@ OMSF-30 catalyst. ② the activity evaluation is carried out on the catalyst, the catalyst is initial CH₄And CO₂The conversions were 87% and 78%, respectively, and the maximum energy efficiency value was 2.7 mmol/kJ.

Example 4

The steps and process conditions of this example are the same as those of example 1, except that 0.7g of nickel nitrate is weighed to prepare a metal nickel salt solution, and then Ni/MoC is obtained through the same preparation process_x@ OMSF-6 catalyst. ② the activity evaluation is carried out on the catalyst, the catalyst is initial CH₄And CO₂The conversions were 75% and 68%, respectively, and the maximum energy efficiency value was 2.2 mmol/kJ.

It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.