Nickel-based physical-chemical double limited function catalyst, its macro-quantity preparation method and application

Abstract

This invention belongs to the field of low-carbon alkane energy value-added and carbon neutrality technology, specifically involving nickel-based physicochemically confined functional catalysts and their large-scale preparation and applications. The catalyst of this invention is prepared using a microemulsion method and is a hollow nanotube-shaped coated shell anchoring intermetallic compound Ni-MO. x A physical-chemical dual-confined catalyst (M is La, Ce, Mg or V) combines the physical confinement effect of nanoreactors, the electronic structure of intermetallic compound nanoparticles, and the nano-quantum effect of intermetallic compounds (including single atoms, clusters or sub-nano islands) to promote the synthesis of syngas from low-carbon alkanes in conjunction with CO2 reforming.

Description

Technical Field

[0001] This invention belongs to the field of low-carbon alkane energy value-added and carbon neutrality technology, specifically involving nickel-based physical-chemical dual-confined functional catalysts and their large-scale preparation and application. Background Technology

[0002] In the catalytic conversion of low-carbon alkanes (C1-C4), carbon dioxide is used as the oxidant. Through the selective cracking of the C-C bonds in low-carbon hydrocarbons, industrial waste gases such as coal chemical off-gas or unconventional natural gas resources such as coalbed methane and shale gas can be converted into high-quality chemical feedstock—syngas. Syngas can then be used for hydrogen production or converted into valuable chemicals through FT synthesis. This reaction has the dual significance of low-carbon alkane resource utilization and CO2 emission reduction. Simultaneously, the thermodynamic equilibrium temperature differences between different low-carbon alkane components (mainly CH4 and C2H6 or C3H8) and CO2 reforming also create conditions for the reactive separation of the first major component (methane) of coalbed methane and shale gas. However, this reaction has C... 2+ The reaction faces the challenge of competitive breaking between C-C bonds and CH bonds in alkanes, meaning the reaction may proceed towards reforming or dehydrogenation. Furthermore, C2* species are prone to rapid polymerization and cyclization during the reaction, leading to severe carbon deposition. Therefore, this reaction requires a highly active, selective, and stable catalyst system.

[0003] Ni-based catalysts, due to their catalytic activity comparable to noble metals, hold potential for industrial applications in reforming reactions. Furthermore, Ni metal exhibits strong C / C and CH bond cleavage capabilities, enabling it to dominate the selection of the conversion pathway from low-carbon alkanes to carbon dioxide and then to syngas (H₂ + CO). However, under harsh reaction conditions, it is prone to sintering and carbon deposition, leading to deactivation. To address this issue, nanoreactor structures with three-dimensional spatial confinement effects (Core-shell, Yolk-shell, multi-shell nanospheres, nanoflowers, etc.) have attracted widespread attention. These structures maximally restrict the migration and aggregation of metal particles and the free growth space for carbon deposits, exhibiting the strongest resistance to sintering and carbon deposition. In addition, research has found that changes in the chemical environment of the catalytic active sites affect the selectivity of reaction products. Intermetallic compounds (nanoparticles formed by metal-metal oxide composites, i.e., Me₁-Me₂O) are particularly effective in controlling the selection of reaction products. xMe1 and Me2 represent two different types of metals. As an atomically ordered alloy with a regular surface or near-surface atomically ordered structure and unique electronic properties, it exhibits excellent catalytic performance in many chemical reactions. However, due to the limitations of current nanoreactor catalyst preparation technology, it is still difficult to achieve the eutectic growth and structural composite of metal cores and doped oxide cores in nanoreactors under large-scale preparation conditions while ensuring the integrity of the three-dimensional spatial confinement structure of monodisperse nanoreactors. Furthermore, it is impossible to effectively control the various components and structures of nanoreactors coated with intermetallic compound cores, as well as the doping form of intermetallic compound cores, and to significantly improve the function of specific catalytic reactions (such as the activity, stability, and anti-carbon deposition ability of the low-carbon alkane-carbon dioxide reforming to syngas reaction). Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention employs a microemulsion method to prepare a hollow nanotube-shaped coated shell anchoring intermetallic compound, Ni-MO. x A physical-chemical dual-confined catalyst (M is La, Ce, Mg or V) combines the physical confinement effect of nanoreactors, the electronic structure of intermetallic compound nanoparticles, and the nano-quantum effect of intermetallic compounds (including single atoms, clusters or sub-nano islands) to promote the synthesis of syngas from low-carbon alkanes in conjunction with CO2 reforming.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a nickel-based physical-chemical dual-confined functional catalyst, which has a completely monodisperse and closed nanotube-like coating structure. A unidirectionally grown hollow nanoscale structure serves as the physical shell, and a highly sub-nanosized, eutectic-grown intermetallic compound serves as the core and is uniformly anchored in the shell. The shell is composed of one of SiO2, Al2O3, or SiO2-Al2O3. The metal phase in the intermetallic compound is nickel, and the oxide phase is at least one of lanthanum oxide, cerium oxide, magnesium oxide, or vanadium oxide.

[0007] Furthermore, the nanotubes have a diameter of 4–20 nm and a length of 5–100 nm; the shell wall thickness is 0.1–8 nm, and the intermetallic compound particle size is 0.5–10 nm.

[0008] Furthermore, the weight percentages of each component in the catalyst are as follows: SiO2+Al2O3: 77.5–98.9 wt%, nickel phase: 0.5–15 wt%, and oxide phase: 0.6–7.5 wt%.

[0009] Another aspect of the present invention provides a method for preparing a nickel-based physicochemically confined functional catalyst as described above, comprising the following steps:

[0010] Step 1: Mix the metal precursor salt and the metal oxide precursor salt and dissolve them in distilled water to prepare aqueous solution A; dissolve the nonionic surfactant in an organic solvent to prepare oil solution B;

[0011] Step 2: At a certain temperature, aqueous solution A is added dropwise to oil solution B to form a water-in-oil mixture system with good Ni-M coordination; then hydrazine hydrate is added dropwise to the above water-in-oil mixture system to form a turbid suspension system.

[0012] Step 3: After aging, at least one of tetraethyl orthosilicate, aluminum isopropoxide, and ammonia are added to the suspension. The mixture is stirred, centrifuged, and the precipitate is dried, calcined, and reduced to obtain the catalyst.

[0013] Further, in step 1, the molar ratio of the metal precursor salt to the metal oxide precursor salt is 1:0.02 to 0.4, the metal precursor salt is any one of nickel nitrate, nickel chloride, and nickel acetate, and the metal oxide precursor salt is at least one of lanthanum nitrate, cerium nitrate, magnesium nitrate, and ammonium metavanadate.

[0014] Further, in step 1, the nonionic surfactant is any one of polyoxyethylene alkyl ether and polyethylene glycol or a mixture thereof; wherein, the polyoxyethylene alkyl ether is any one of polyoxyethylene (5) hexadecyl ether, polyoxyethylene (10) hexadecyl ether, polyoxyethylene (12) tridecyl ether, polyoxyethylene (20) octadecyl ether, polyoxyethylene (20) hexadecyl ether, and polyoxyethylene (30) hexadecyl ether; the polyethylene glycol is one of polyethylene glycol 200, polyethylene glycol 600, and polyethylene glycol 1000; and the molar ratio of polyoxyethylene alkyl ether to polyethylene glycol is 1:0 to 0.5.

[0015] Furthermore, in step 1, the Ni concentration in the aqueous solution A is 0.2–5 mol / L. -1 The oxide concentration is 0.03–2 mol L. -1 The concentration of oil phase solution B is 0.2–5 mol / L. -1 .

[0016] Furthermore, in step 1, the volume of aqueous solution A is 200 mL and the volume of oil solution B is 4 L.

[0017] Furthermore, the temperature in step 2 is 30–80°C.

[0018] Furthermore, in step 2, the dropping rate of aqueous solution A is 1–10 mL / min, the dropping rate of oil solution B is 5–120 mL / min, the dropping rate of hydrazine hydrate is 0.1–10 mL / min, and the amount of hydrazine hydrate added is 120–160 mL.

[0019] Furthermore, the aging time in step 3 is 5 to 10 hours.

[0020] Furthermore, in step 3, the dropping rate of tetraethyl orthosilicate and / or aluminum isopropoxide and ammonia is 0.1 to 50 mL / min.

[0021] Furthermore, in step 3, the amount of tetraethyl orthosilicate added is 10-1000 mL, the amount of aluminum isopropoxide added is 50-700 mL, the amount of ammonia added is 1-1000 mL, and the concentration is 25%.

[0022] Furthermore, the stirring time in step 3 is 10 to 36 hours.

[0023] Furthermore, in step 3, the drying temperature is 40–80°C, and the drying time is 12–24 hours.

[0024] Furthermore, the calcination in step 3 specifically involves: calcining at 80–200°C for 1–2 hours under a flowing or static air or nitrogen atmosphere, followed by raising the temperature to 180–750°C and calcining for 3–4 hours.

[0025] Furthermore, in step 3, the reduction temperature is 500–900°C, the reduction time is 2–10 h, and the reduction atmosphere is hydrogen or a mixture of hydrogen and nitrogen, wherein the flow ratio of hydrogen to nitrogen is 1:0–3.

[0026] The preparation principle of the nickel-based physicochemical dual-confined functional catalyst of this invention is as follows: using a mixed solution of metal phase and metal oxide phase precursor salt as the aqueous phase, an organic solvent containing a nonionic surfactant is added to form a typical water-in-oil system. Subsequently, N2H4·H2O is dissolved in the aqueous phase and reacts with Ni. 2+ Rapid complexation forms large-particle nuclei such as Ni(N2H4)3(NO3)2 / [Ni(N2H4)3]Cl2 / Ni(N2H4)3(Ac)2, which extend at both ends in a one-dimensional expansion mode to form solid-phase nanorod-shaped metal (Ni) organic complexes. Meanwhile, the uncomplexed metal oxide precursors utilize the alkaline conditions provided by the hydrolysis of N2H4·H2O to form M(OH)2. y Microcrystalline nuclei are adsorbed and encapsulated within the metal-organic complex nanorod framework. Subsequently, a silicon (aluminum) source is added. The N-OH and NH groups present in the solid-phase nanorods readily associate with the -O-Si(Al)- groups in TEOS / aluminum isopropoxide, promoting the hydrolysis and polymerization of silicates / aluminates. This results in the formation of a SiO2 (SiO2-Al2O3) shell using the solid-phase nanorods as a hard template, encapsulating the nanorods internally. Finally, during calcination at relatively low temperatures, the -(N-OH) groups in the metal-organic complex nanorod structure... xBond dissociation and volatilization in gaseous form lead to the decomposition of the nanorods, while the SiO2 (SiO2-Al2O3) shell structure is successfully preserved, forming a one-dimensional tubular hollow structure inside the cavity. Furthermore, the high-temperature calcination process of Ni and the metal oxide phase overcomes the kinetic energy barrier for atomic rearrangement in the solid phase, and their similar atomic radii further promote eutectic growth to form NiLaO. y NiCeO y NiMgO y NiVO y After reducing the solid solution microcrystalline particles, the Ni component in the solid solution is selectively reduced, while the Ni component is retained along with the MO component. x The chemical bonding at the interface transforms into Ni-MO with a highly dispersed sub-nanometer, clustered, or single-atom MOx oxide composition distribution. x Intermetallic phase structure core.

[0027] In another aspect, this invention provides the application of the nickel-based physicochemical dual-confined functional catalyst as described above in the combined CO2 reforming of low-carbon alkanes to syngas, wherein the low-carbon alkanes are one of ethane, propane, butane, and methane, preferably methane or ethane. When applied to the low-carbon alkane CO2 reforming reaction, this catalyst exhibits excellent alkane and CO2 conversion rates, syngas selectivity, and outstanding anti-sintering and anti-coking properties.

[0028] Furthermore, the method for producing syngas by combined CO2 reforming of low-carbon alkanes includes the following steps:

[0029] The reaction tube is filled with catalyst particles of 20-80 mesh, the amount of catalyst is 0.05-5 g, the reaction temperature is 600-850℃, the reaction pressure is 0.1 MPa, the reaction inlet gas ratio is C2H6 or CH4:CO2:N2=1:(1-2.4):(0-4), and the reaction space velocity is 7200-96000 mL / (h·g).

[0030] The application principle of the nickel-based physicochemical dual-confinement functional catalyst of this invention is as follows: It utilizes the intermetallic chemical confinement of the catalyst in conjunction with the physical confinement of the hollow nanotube-shaped coating layer to achieve selectivity of the C / C bond breaking pathway and resistance to carbon deposition in the combined carbon dioxide reforming reaction of low-carbon alkanes. After catalyst reduction, metallic Ni reacts with oxides La₂O₃, CeO₂, MgO, and V₂O₅ as the intermetallic compound Ni-MO. x The existence of Ni-MO is due to the charge imbalance between the metal and the metal oxide. x The generation of numerous bulk defects in the Ni-CeO2 / Ni-V2O5 species facilitates the opening of reaction pathways, thereby promoting the conversion of a large amount of bulk lattice oxygen in CeO2 / V2O5 into surface-active oxygen O*, acting as an "oxygen pump." Furthermore, the intermetallic compound Ni-MO...x The formation of this reduces the binding energy between CH3CH2* and O* after C2H6 activation, thereby promoting the formation of C2H6 in Ni-MO. x At the site, it preferentially exists in the form of CH3CH2(O)*, and then proceeds through CH3CH2(O)*→CH3CH(O)*→CH x The conversion of (O)* to CO towards syngas blocks the formation of olefins from CH3CH2* through deep dehydrogenation. Simultaneously, sufficient reactive oxygen species facilitate the oxidation of C2* species or the elimination of surface carbon, thus achieving a balance between carbon species conversion and elimination. For Ni-La2O3 / Ni-MgO intermetallic compounds, the intermetallic compound sites enable CO2 to not only be activated at Ni sites but also react with La2O3 / MgO species to form La2O2CO3 / MgO-CO2. The active oxygen O* generated during the in-situ redox cycle is beneficial for the elimination of carbon deposits and also participates in the generation of CH3CH2O* species, thus improving the selectivity of C-C bond cleavage.

[0031] In addition, the intermetallic compound Ni-MO produced after reduction x Within the core, some metal oxides are doped into the Ni lattice, causing the Ni nuclei to expand and increasing the lattice parameters of the metal core. This phenomenon facilitates the infiltration of C2* / C1* species generated during the reaction into the intermetallic compound lattice interstices, thus generating more interstitial carbon. Interstitial carbon, acting as an intermediate, can rapidly react with CO2 to generate CO products for removal, rather than polymerizing or cyclizing to form graphite carbon, thereby preventing catalyst deactivation due to carbon buildup. Simultaneously, the unique physical confinement function provided by the catalyst's hollow nanotube framework structure hinders metal sintering and carbon growth during the reaction. The physical confinement provided by the nanotube framework, combined with the unique chemical environment on the surface of the intermetallic compound core, creates a physical-chemical dual confinement function, achieving efficient conversion of low-carbon alkanes and CO2 into syngas.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] 1) The catalyst prepared by this invention can achieve monodisperse, unidirectionally growing nanoscale hollow tubular structures with a size of 5–100 nm. The one-dimensional structure of the catalyst is determined by the growth kinetics of the intrinsic nanorod-shaped metal (Ni) organic complex; that is, the one-dimensional growth of the nanorod-shaped metal (Ni) organic complex is jointly controlled by the amounts of Ni source and N₂H₄·H₂O, and their ratio determines the final length. With increasing N₂H₄ content, the metal (Ni) organic complex gradually increases, and the nanotube length gradually increases, thus achieving size control of the nanoscale hollow tubular structure. Furthermore, the 5–100 nm nanoscale hollow tubular structure further restricts the eutectic growth size of the metal core and the doped oxide core.

[0034] 2) The beneficial effect of the two-stage variable-temperature calcination method in the catalyst preparation process of this invention, involving first low-temperature (80-200℃) and then high-temperature (180-750℃), is that it can obtain a physicochemically dual-confined catalyst with a highly nano-sized intermetallic compound as the core and uniformly anchored in an intact shell. The first stage of low-temperature calcination firstly transforms the Ni-(N-OH) in the metal (Ni) organic complex nanorod structure... x Bond dissociation allows the nanorods to decompose, successfully preserving the one-dimensional extended shell structure. Then, during the second stage of high-temperature calcination, Ni and metal oxides overcome the kinetic energy barrier of atomic rearrangement in the solid phase. In addition, the shell framework formed during low-temperature calcination inhibits the severe sintering of metal particles and the reduction of metal surface area during high-temperature heat treatment, thereby forming an intermetallic compound core with highly nano-sized metal oxides incorporated into Ni crystal nuclei within the shell framework.

[0035] 3) This invention uses dual template agents (polyoxyethylene alkyl ether and polyethylene glycol) to induce a water-in-oil microemulsion system. The combined guiding effect of the two template agents achieves a "micro-meso-meso" hierarchical porous structure of the catalyst (e.g., Figure 1 and Figure 4 As shown in the figure, this enhances the accessibility of reactants to active sites within the pores. Furthermore, during the high-temperature drying and calcination of the catalyst precursor, the template agent also weakens the interfacial energy and capillary forces in the mesopores, thereby reducing the surface tension within the mesopores and inhibiting particle aggregation.

[0036] 4) In the intermetallic compound core obtained by the present invention, the different doping amounts of the metal oxide can effectively control its doping form. When the doping amount of one or two of the oxides is <1wt%, the metal oxide is distributed in the Ni crystal grain in the form of single atoms. When the doping amount of one or two of the oxides is between 1 and 3wt%, the metal oxide exists in the Ni crystal core in the form of substituted nanocluster islands (0.3 to 2nm). When the doping amount of one or two of the oxides is >3wt%, the metal oxide and the Ni crystal core exist in the form of fine nanoparticles (2 to 10nm).

[0037] 5) The catalyst prepared in this invention exhibits both physicochemical confinement effects. The unique interstitial carbon intermediate transformation within the intermetallic compound core and the surface-active oxygen promote the efficient conversion of carbon-containing species to the product CO. Simultaneously, the catalyst's hollow nanotube framework provides a fully encapsulated confinement environment, achieving a confinement effect on the metal sites, maintaining the dispersed state of the metal, and to some extent limiting the degrees of freedom in the carbon species formation process, hindering the growth space for carbon deposits. Furthermore, the tunable chemical properties of the metal compound can effectively stabilize the key intermediate CH3CH2O*, which involves C / C bond cleavage, at the single-atom or nanocluster level, thus enabling a highly selective conversion of low-carbon alkanes and CO2 to syngas. When applied to the ethane-carbon dioxide reforming reaction, the catalyst prepared in this invention can achieve stable operation for more than 400 hours.

[0038] 6) This invention ensures that the hollow nanotube-shaped coating layer anchors the intermetallic compound Ni-MO. x Under the premise that the physical-chemical dual-confined catalyst monodisperse nanoreactor structure is intact, the batch production of the catalyst is greater than 100g. By scaling up the preparation system, the batch production of the catalyst can reach the kg level. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the nickel-based physicochemical dual-confined functional catalyst of the present invention.

[0040] Figure 2 This is a TEM image of the physicochemically confined catalyst in Example 1, which uses a hollow nanotube-shaped coating shell to anchor the intermetallic compound Ni-La2O3.

[0041] Figure 3 This is an aberration-corrected STEM energy distribution diagram of the intermetallic compound Ni-La2O3 anchored by the hollow nanotube-shaped coating shell in Example 1.

[0042] Figure 4This is a pore size distribution diagram of the physicochemical dual-confined catalyst with hollow nanotube-shaped coated shell anchoring the intermetallic compound Ni-CeO2 in Example 2.

[0043] Figure 5 This is a graph showing the ethane-carbon dioxide activity evaluation of the physicochemically confined catalyst in Example 2, which uses a hollow nanotube-coated shell to anchor the intermetallic compound Ni-CeO2. Detailed Implementation

[0044] To facilitate understanding of the present invention, a more comprehensive description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0045] Preparation Example 1

[0046] Using distilled water as a solvent, nickel nitrate and lanthanum nitrate were dissolved in distilled water at a molar ratio of 1:0.1 to prepare 200 mL of solution with a Ni concentration of 1.5 mol / L. -1 The concentration of lanthanum nitrate is 0.15 mol / L. -1 In aqueous solution A, polyoxyethylene (12) tridecyl ether and polyethylene glycol (200) nonionic surfactant were dissolved in cyclohexane at a molar ratio of 1:0.1 to prepare 4 L of solution with a concentration of 3 mol / L. -1 Oil phase solution B; Under conditions of 50°C, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 5 mL / min and the dropping rate of oil phase solution B controlled at 30 mL / min, forming a well-coordinated Ni-La water-in-oil mixture; then, 120 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 2 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 5 hours, 500 mL of tetraethyl orthosilicate and 750 mL of... were added using a peristaltic pump at a rate of 30 mL / min. 25% ammonia solution was stirred vigorously for 10 hours using a stirrer. The mixture was then centrifuged with isopropanol, and the resulting precipitate was dried at 80°C for 12 hours. The sample was then placed in a muffle furnace, and flowing air was introduced. The furnace was first calcined at 150°C for 1 hour, then the temperature was increased to 700°C and calcined for 3 hours. Finally, the precipitate was reduced in situ at 700°C for 6 hours under a 1:3 H2 / N2 mixture to obtain catalyst 1. TEM images and aberration-corrected STEM elemental distribution diagrams of catalyst 1 are shown below. Figure 2 , Figure 3 As shown.

[0047] Preparation Example 2

[0048] Using distilled water as a solvent, nickel chloride and cerium nitrate were dissolved in distilled water at a molar ratio of 1:0.4 to prepare 200 mL of solution with a Ni concentration of 5 mol / L. -1 The concentration of cerium nitrate is 2 mol / L. -1 In aqueous solution A, polyoxyethylene (5) hexadecyl ether and polyethylene glycol (600) nonionic surfactant were dissolved in n-hexane at a molar ratio of 1:0.05 to prepare 4 L of solution with a concentration of 5 mol / L. -1 Oil phase solution B; Under conditions of 60℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 8 mL / min and the dropping rate of oil phase solution B controlled at 42 mL / min, forming a well-coordinated Ni-Ce water-in-oil mixture; then, 140 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 5 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 7 hours, 400 mL of tetraethyl orthosilicate, 200 mL of aluminum isopropoxide, and 800 mL of... were added at a rate of 35 mL / min using a peristaltic pump. 25% ammonia solution was stirred vigorously for 24 hours using a stirrer. The mixture was then centrifuged with isopropanol, and the resulting precipitate was dried at 60°C for 18 hours. The sample was then placed in a muffle furnace, and static air was introduced. The furnace was first calcined at 130°C for 2 hours, then the temperature was increased to 600°C and calcined for 4 hours. Finally, the precipitate was reduced in situ at 800°C for 7 hours under a 1:2 H2 / N2 mixture to obtain catalyst 2. The pore size distribution of catalyst 2 is shown in the figure below. Figure 4 As shown.

[0049] Preparation Example 3

[0050] Using distilled water as a solvent, nickel acetate and ammonium metavanadate were dissolved in distilled water at a molar ratio of 1:0.2 to prepare 200 mL of solution with a Ni concentration of 2 mol / L. -1 The concentration of ammonium metavanadate is 0.5 mol / L. -1 In aqueous solution A, polyoxyethylene (10) hexadecyl ether nonionic surfactant was dissolved in n-hexane to prepare 4 L of solution with a concentration of 3.5 mol / L. -1Oil phase solution B; Under conditions of 80℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 9 mL / min and the dropping rate of oil phase solution B controlled at 80 mL / min, forming a well-coordinated Ni-V water-in-oil mixture; then, 130 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 3 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 6 hours, 500 mL of tetraethyl orthosilicate, 300 mL of aluminum isopropoxide, and 850 mL of... were added at a rate of 45 mL / min using a peristaltic pump. 25% ammonia water was stirred vigorously with a stirrer for 12 hours; then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 50°C for 24 hours. The sample was then placed in a muffle furnace, and flowing nitrogen was introduced. The sample was first calcined at 200°C for 1 hour, and then the temperature was raised to 750°C and calcined for 3 hours. Finally, the sample was reduced in situ at 800°C for 5 hours under H2 atmosphere to obtain catalyst 3.

[0051] Preparation Example 4

[0052] Using distilled water as a solvent, nickel chloride and magnesium nitrate were dissolved in distilled water at a molar ratio of 1:0.15 to prepare 200 mL of solution with a Ni concentration of 0.2 mol / L. -1 The concentration of magnesium nitrate is 0.03 mol / L. -1 In aqueous solution A, polyoxyethylene (12) tridecyl ether nonionic surfactant was dissolved in cyclohexane to prepare 4 L of solution with a concentration of 2 mol / L. -1 Oil phase solution B; Under conditions of 70℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 8.5 mL / min and the dropping rate of oil phase solution B controlled at 65 mL / min, forming a well-coordinated Ni-Mg water-in-oil mixture; then, 120 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 0.1 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 9 hours, 250 mL of tetraethyl orthosilicate, 100 mL of aluminum isopropoxide, and 650 mL of... were added using a peristaltic pump at a rate of 25 mL / min. 25% ammonia water was stirred vigorously with a stirrer for 36 hours. Then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 70°C for 12 hours. The sample was then placed in a muffle furnace, and static nitrogen gas was introduced. The sample was first calcined at 160°C for 1 hour, and then the temperature was raised to 750°C and calcined for 3 hours. Finally, the sample was reduced in situ at 700°C for 6 hours under a H2 / N2 mixed gas with a flow rate ratio of 1:2 to obtain catalyst 4.

[0053] Preparation Example 5

[0054] Using distilled water as a solvent, nickel nitrate and cerium nitrate were dissolved in distilled water at a molar ratio of 1:0.02 to prepare a 200 mL solution with a Ni concentration of 2.5 mol / L. -1 The concentration of cerium nitrate is 0.05 mol / L. -1 In aqueous solution A, polyoxyethylene (20) octadecyl ether nonionic surfactant was dissolved in n-hexane to prepare 4 L of solution with a concentration of 0.2 mol / L. -1 Oil phase solution B; Under conditions of 60℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 10 mL / min and the dropping rate of oil phase solution B controlled at 120 mL / min, forming a well-coordinated Ni-Ce water-in-oil mixture; then, 145 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 5 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 10 h, 300 mL of tetraethyl orthosilicate, 180 mL of aluminum isopropoxide, and 800 mL of... were added at a rate of 35 mL / min using a peristaltic pump. 25% ammonia water was stirred vigorously with a stirrer for 24 hours. Then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 60°C for 12 hours. The sample was then placed in a muffle furnace, and flowing air was introduced. The sample was first calcined at 140°C for 1.5 hours, and then the temperature was raised to 700°C and calcined for 4 hours. Finally, the sample was reduced in situ at 500°C for 10 hours under a 1:1 H2 / N2 mixed gas flow rate to obtain catalyst 5.

[0055] Preparation Example 6

[0056] Using distilled water as a solvent, nickel acetate, lanthanum nitrate, and cerium nitrate were dissolved in distilled water at a molar ratio of 1:0.3:0.3 to prepare a 200 mL solution with a Ni concentration of 3 mol / L. -1 The concentrations of lanthanum nitrate and cerium nitrate were both 0.9 mol / L. -1 In aqueous solution A, polyoxyethylene (10) octadecyl ether nonionic surfactant was dissolved in cyclohexane to prepare 4 L of solution with a concentration of 4 mol / L. -1Oil phase solution B; Under conditions of 50°C, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 1 mL / min and the dropping rate of oil phase solution B controlled at 56 mL / min, forming a well-coordinated Ni-La-Ce water-in-oil mixture; then, 150 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 9 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 8 hours, 700 mL of aluminum isopropoxide and 500 mL of... were added using a peristaltic pump at a rate of 20 mL / min. 25% ammonia water was stirred vigorously with a stirrer for 12 hours. Then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 40°C for 12 hours. The sample was then placed in a muffle furnace, and static air was introduced. The sample was first calcined at 80°C for 2 hours, and then the temperature was raised to 180°C and calcined for 4 hours. Finally, the sample was reduced in situ at 600°C for 2 hours under a 1:1 H2 / N2 mixed gas to obtain catalyst 6.

[0057] Preparation Example 7

[0058] Using distilled water as a solvent, nickel nitrate, cerium nitrate, and magnesium nitrate were dissolved in distilled water at a molar ratio of 1:0.35:0.35 to prepare 200 mL of solution with a Ni concentration of 5 mol / L. -1 The concentration of cerium nitrate is 2 mol / L. -1 The concentration of magnesium nitrate is 2 mol / L. -1 In aqueous solution A, polyoxyethylene (30) hexadecyl ether nonionic surfactant was dissolved in n-hexane to prepare 4 L of solution with a concentration of 3 mol / L. -1 Oil phase solution B; Under conditions of 70℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 7 mL / min and the dropping rate of oil phase solution B controlled at 70 mL / min, forming a well-coordinated Ni-Ce-Mg water-in-oil mixture; then, 145 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 8 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 6 hours, 1000 mL of tetraethyl orthosilicate and 1000 mL of... were added using a peristaltic pump at a rate of 50 mL / min. 25% ammonia solution was stirred vigorously with a stirrer for 36 hours. Then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 60°C for 12 hours. The sample was then placed in a muffle furnace, and flowing nitrogen was introduced. The sample was first calcined at 100°C for 2 hours, and then the temperature was raised to 500°C and calcined for 4 hours. Finally, the sample was reduced in situ at 700°C for 3 hours under H2 atmosphere to obtain catalyst 7.

[0059] Preparation Example 8

[0060] Using distilled water as a solvent, nickel chloride and ammonium metavanadate were dissolved in distilled water at a molar ratio of 1:0.4 to prepare a 200 mL solution with a Ni concentration of 3.75 mol / L. -1 The concentration of ammonium metavanadate was 1.5 mol / L. -1 In aqueous solution A, polyoxyethylene (5) hexadecyl ether and polyethylene glycol (1000) nonionic surfactant were dissolved in cyclohexane at a molar ratio of 1:0.2 to prepare 4 L of solution with a concentration of 2.5 mol / L. -1 Oil phase solution B; Under conditions of 80℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 3 mL / min and the dropping rate of oil phase solution B controlled at 92 mL / min, forming a well-coordinated Ni-V water-in-oil mixture; then, 150 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 9 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 5 hours, 10 mL of tetraethyl orthosilicate and 1 mL of... were added at a rate of 0.1 mL / min using a peristaltic pump. 25% ammonia water was stirred vigorously with a stirrer for 10 hours; then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 50°C for 12 hours. The sample was then placed in a muffle furnace, and static nitrogen gas was introduced. The sample was first calcined at 200°C for 1 hour, and then the temperature was raised to 650°C and calcined for 3 hours. Finally, the sample was reduced in situ at 900°C for 2 hours under a H2 / N2 mixture with a flow rate ratio of 1:3 to obtain catalyst 8.

[0061] Preparation Example 9

[0062] Using distilled water as a solvent, nickel acetate, magnesium nitrate, and ammonium metavanadate were dissolved in distilled water at a molar ratio of 1:0.375:0.375 to prepare a 200 mL solution with a Ni concentration of 4.8 mol / L. -1 The concentrations of magnesium nitrate and ammonium metavanadate were 1.8 mol / L. -1 In aqueous solution A, polyoxyethylene (10) hexadecyl ether and polyethylene glycol (600) nonionic surfactant were dissolved in n-hexane at a molar ratio of 1:0.05 to prepare 4 L of solution with a concentration of 4.5 mol / L. -1Oil phase solution B; Under conditions of 80℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 6 mL / min and the dropping rate of oil phase solution B controlled at 92 mL / min, forming a well-coordinated Ni-Mg-V water-in-oil mixture; then, 160 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 10 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 7 hours, 200 mL of tetraethyl orthosilicate, 400 mL of aluminum isopropoxide, and 400 mL of... were added at a rate of 20 mL / min using a peristaltic pump. 25% ammonia water was stirred vigorously with a stirrer for 24 hours. Then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 70°C for 18 hours. The sample was then placed in a muffle furnace, and flowing air was introduced. The sample was first calcined at 180°C for 1 hour, and then the temperature was raised to 550°C and calcined for 4 hours. Finally, the sample was reduced in situ at 800°C for 3 hours under a H2 / N2 mixture with a flow rate ratio of 1:2 to obtain catalyst 9.

[0063] Preparation Example 10

[0064] Using distilled water as a solvent, nickel nitrate and lanthanum nitrate were dissolved in distilled water at a molar ratio of 1:0.15 to prepare 200 mL of solution with a Ni concentration of 1 mol / L. -1 The concentration of lanthanum nitrate is 0.15 mol / L. -1 In aqueous solution A, polyoxyethylene (5) hexadecyl ether was dissolved in cyclohexane to prepare 4 L of solution with a concentration of 1 mol / L. -1 Oil phase solution B; Under conditions of 60℃, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 2 mL / min and the dropping rate of oil phase solution B controlled at 100 mL / min, forming a well-coordinated Ni-La water-in-oil mixture; then, 130 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 8 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 9 hours, 10 mL of hydrazine hydrate was added dropwise using a peristaltic pump. Add 50 mL of tetraethyl orthosilicate, 50 mL of aluminum isopropoxide, and 150 mL of 25% ammonia water at a rate of / min, and maintain vigorous stirring with a stirrer for 36 h. Then, separate the precipitate by centrifugation with isopropanol, and dry the precipitate at 80 °C for 12 h. After that, put the sample into a muffle furnace, introduce flowing nitrogen gas, and calcine it at a low temperature of 160 °C for 2 h, then raise the temperature to 700 °C and calcine it for 3 h. Finally, reduce it in situ at 750 °C for 5 h under H2 atmosphere to obtain catalyst 10.

[0065] Preparation Example 11

[0066] Using distilled water as a solvent, nickel chloride and magnesium nitrate were dissolved in distilled water at a molar ratio of 1:0.25 to prepare 200 mL of solution with a Ni concentration of 3 mol / L. -1 The concentration of magnesium nitrate is 0.75 mol / L. -1 In aqueous solution A, polyoxyethylene (20) hexadecyl ether and polyethylene glycol (200) nonionic surfactant were dissolved in cyclohexane at a molar ratio of 1:0.5 to prepare 4 L of solution with a concentration of 2.5 mol / L. -1 Oil phase solution B; Under 30°C, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 5 mL / min and the dropping rate of oil phase solution B controlled at 60 mL / min, forming a well-coordinated Ni-Mg water-in-oil mixture; then, 135 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 4 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 8 hours, 600 mL of tetraethyl orthosilicate and 800 mL of... were added using a peristaltic pump at a rate of 50 mL / min. 25% ammonia water was stirred vigorously with a stirrer for 12 hours. Then, isopropanol was used for centrifugation, and the resulting precipitate was dried at 60°C for 12 hours. The sample was then placed in a muffle furnace, and flowing air was introduced. The sample was first calcined at 130°C for 2 hours, and then the temperature was raised to 700°C and calcined for 4 hours. Finally, the sample was reduced in situ at 750°C for 3 hours under a H2 / N2 atmosphere with a flow ratio of 1:3 to obtain catalyst 11.

[0067] Application Example 1

[0068] Catalyst 1 prepared in Example 1 was granulated, and 0.1 g of 20-40 mesh particles was weighed for methane-to-carbon dioxide reforming reaction activity testing: a CH4:CO2 mixture of 1:1 was introduced at 700°C and 0.1 MPa, with a space velocity of 96000 ml / g / h. Under these conditions, Catalyst 1 achieved stable operation for 500 h, with initial conversions of methane and CO2 of 75.8% and 79.8%, respectively, decreasing to 73.9% and 78.2% after 800 h. Furthermore, the CO selectivity in the generated gas remained stable at 96.7%.

[0069] Application Example 2

[0070] Catalyst 2 prepared in Example 2 was granulated, and 0.05 g of 40-60 mesh particles were weighed for ethane-to-carbon dioxide reforming reaction activity testing: a mixed gas of C2H6:CO2:N2 = 1:2:3 was introduced at 700℃ and 0.1 MPa, with a space velocity of 36000 ml / g / h. Under these conditions, catalyst 2 achieved stable operation for 400 h, with an average ethane conversion rate of 95.2% and a deactivation rate of less than 0.01% / h within 400 h, an average CO2 conversion rate of 88.6%, and a CO selectivity stable at 87.8% (e.g., ...). Figure 5 ).

[0071] Application Example 3

[0072] The catalyst 3 prepared in Example 3 was granulated, and 0.2 g of 40-60 mesh particles were weighed for ethane-to-carbon dioxide reforming reaction activity testing: a mixed gas of C2H6:CO2:N2 = 1:2.4:4 was introduced at 750℃ and 0.1 MPa, with a space velocity of 22200 mL / g / h. The average ethane conversion rate after 50 h was 97.5%, and the deactivation rate within 400 h was less than 0.01% / h. The average CO2 conversion rate was 87.3%, and the CO selectivity remained stable at 93.2%.

[0073] Application Example 4

[0074] The catalyst 4 prepared in Example 4 was granulated, and 5g of 60-80 mesh particles were weighed for ethane-to-carbon dioxide reforming reaction activity testing: a C2H6:CO2 mixture of 1:1 was introduced at 650℃ and 0.1MPa, with a space velocity of 24000mL / g / h. After 300h of reaction, the average ethane conversion rate was 87.5%, the average CO2 conversion rate was 84.7%, and the CO selectivity remained stable at 89.2%.

[0075] Application Example 5

[0076] The catalyst 5 prepared in Example 5 was granulated, and 0.1 g of 20-40 mesh particles was weighed for methane-carbon dioxide reforming to syngas reaction activity testing: a CH4:CO2:N2 mixture of 1:1:1 was introduced at 750℃ and 0.1 MPa, with a space velocity of 48000 mL / g / h. After 400 h of reaction, the average methane conversion rate was 84.9%, the average CO2 conversion rate was 91.3%, and the CO selectivity remained stable at 92.2%.

[0077] Application Example 6

[0078] Catalyst 6 prepared in Example 6 was granulated, and 0.05 g of 40-60 mesh particles were weighed for methane-carbon dioxide reforming to syngas reaction activity testing: a mixed gas of CH4:CO2:N2 = 1:1:2 was introduced at 800℃ and 0.1 MPa, with a space velocity of 96000 mL / g / h. After 500 h of reaction, the average methane conversion rate was 91.1%, the average CO2 conversion rate was 92.5%, and the CO selectivity remained stable at 95.5%.

[0079] Application Example 7

[0080] The catalyst 7 prepared in Example 7 was granulated, and 0.1 g of 20-40 mesh particles was weighed for ethane-to-carbon dioxide reforming reaction activity testing: a mixed gas of C2H6:CO2:N2 = 1:2:1 was introduced at 600℃ and 0.1 MPa, with a space velocity of 24000 mL / g / h. After 200 h of reaction, the average ethane conversion rate was 83.3%, the average CO2 conversion rate was 83.0%, and the CO selectivity remained stable at 89.5%.

[0081] Application Example 8

[0082] The catalyst 8 prepared in Example 8 was granulated, and 0.05 g of 40-60 mesh particles were weighed for methane-carbon dioxide reforming to syngas reaction activity testing: a mixed gas of CH4:CO2:N2 = 1:1:2 was introduced at 800℃ and 0.1 MPa, with a space velocity of 96000 mL / g / h. After 500 h of reaction, the average methane conversion rate was 91.1%, the average CO2 conversion rate was 92.5%, and the CO selectivity remained stable at 95.4%.

[0083] Application Example 9

[0084] The catalyst 9 prepared in Example 9 was granulated, and 1 g of 60-80 mesh particles was weighed for methane-carbon dioxide reforming to syngas reaction activity testing: a mixed gas of CH4:CO2:N2 = 1:2:3 was introduced at 700℃ and 0.1 MPa, with a space velocity of 7200 mL / g / h. After 300 h of reaction, the average methane conversion rate was 75.4%, the average CO2 conversion rate was 76.6%, and the CO selectivity remained stable at 96.5%.

[0085] Application Example 10

[0086] The catalyst 10 prepared in Example 10 was granulated, and 0.3 g of 20-40 mesh particles were weighed for ethane-to-carbon dioxide reforming reaction activity testing: a mixed gas of C2H6:CO2:N2 = 1:2:3 was introduced at 800℃ and 0.1 MPa, with a space velocity of 72000 mL / g / h. After 500 h of reaction, the average ethane conversion rate was 99.9%, the average CO2 conversion rate was 96.9%, and the CO selectivity remained stable at 95.5%.

[0087] Application Example 11

[0088] The catalyst 11 prepared in Example 11 was granulated, and 0.5 g of 20-40 mesh particles were weighed for methane-carbon dioxide reforming to syngas reaction activity testing: a mixed gas of CH4:CO2:N2 = 1:2.4:4 was introduced at 850 °C and 0.1 MPa, with a space velocity of 8880 mL / g / h. After 400 h of reaction, the average methane conversion rate was 98.5%, the average CO2 conversion rate was 94.9%, and the CO selectivity remained stable at 98.0%.

[0089] Application Example 12

[0090] Catalyst 7 prepared in Example 7 was granulated, and 0.3 g of 40-60 mesh particles were weighed for propane-to-carbon dioxide reforming reaction activity testing: a mixed gas of C3H8:CO2:N2 = 1:3:5 was introduced at 850℃ and 0.1 MPa, with a space velocity of 18000 mL / g / h. After 80 h of reaction, the average propane conversion rate was 97.6%, the average CO2 conversion rate was 98.5%, and the CO selectivity remained stable at 92.5%.

[0091] The texture and structural parameters of each catalyst in the above preparation examples are shown in Table 1.

[0092] Table 1. Texture and structural parameters of catalysts 1-11

[0093]

[0094]

[0095] The above application examples demonstrate that the catalyst of this invention exhibits excellent alkane reforming performance and reaction stability. Taking methane-CO2 reforming as an example, the methane conversion rate reaches 75.4–98.5%, the CO2 conversion rate reaches 76.6–94.9%, and the CO selectivity reaches 92.2–98.0%. Taking ethane-CO2 reforming as an example, the ethane conversion rate reaches 83.3–99.9%, the CO2 conversion rate reaches 83.0–96.9%, and the CO selectivity reaches 87.8–95.5%. The reaction remains stable for more than 80–800 hours.

[0096] The above description is only for better explaining the embodiments of the present invention and is not intended to limit them. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims

1. The application of a nickel-based physicochemical dual-confined functional catalyst, characterized in that: This is used for the combined CO2 reforming of low-carbon alkanes to produce syngas, wherein the low-carbon alkanes are ethane; The catalyst is prepared as follows: Using distilled water as a solvent, nickel chloride and cerium nitrate were dissolved in distilled water at a molar ratio of 1:0.4 to prepare 200 mL of solution with a Ni concentration of 5 mol / L. -1 The concentration of cerium nitrate is 2 mol / L. -1 In aqueous solution A, polyoxyethylene (5) hexadecyl ether and polyethylene glycol 600 nonionic surfactant were dissolved in n-hexane at a molar ratio of 1:0.05 to prepare 4 L of solution with a concentration of 5 mol / L. -1 Oil phase solution B; Under conditions of 60 °C, aqueous phase solution A and oil phase solution B were mixed using a peristaltic pump, with the dropping rate of aqueous phase solution A controlled at 8 mL / min and the dropping rate of oil phase solution B controlled at 42 mL / min, forming a well-coordinated Ni-Ce water-in-oil mixture; then, 140 mL of hydrazine hydrate was added dropwise to the above water-in-oil mixture at a rate of 5 mL / min using a peristaltic pump, forming a turbid suspension system; after the suspension had aged for 7 h, 400 mL of tetraethyl orthosilicate, 200 mL of aluminum isopropoxide, and 800 mL of 25% ammonia water were added at a rate of 35 mL / min using a peristaltic pump, and the mixture was stirred vigorously for 24 h using a stirrer; then, the mixture was separated by centrifugation with isopropanol, and the resulting precipitate was dried at 60 °C for 18 h. The sample was then placed in a muffle furnace, static air was introduced, and the mixture was first calcined at 130 °C for 2 h, then the temperature was increased to 600 °C and calcined for 4 h. h; finally, the catalyst was reduced in situ at 800 °C for 7 h under a H2 / N2 mixture with a flow rate ratio of 1:2 to obtain the catalyst.

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