High-entropy oxide derived nickel-based catalyst, preparation method and coke oven gas tri-reforming application

Abstract

The invention belongs to the technical field of environmental catalysis and carbon neutralization, and particularly relates to a high-entropy oxide derived nickel-based catalyst, a preparation method and coke oven gas tri-reforming application. The preparation method comprises the following steps: mixing and dissolving nickel-containing metal soluble salt and an organic structure-directing agent in deionized water to form a solution a; dissolving soluble alkali in deionized water to form a solution b; carrying out parallel flow precipitation on the solution a and the solution b, and carrying out heating reflux on a precipitate obtained by centrifugation; and after the reflux is finished, centrifuging, drying, calcining and reducing to obtain the high-entropy oxide derived nickel-based catalyst. The high-entropy oxide derived nickel-based catalyst material disclosed by the invention is simple to prepare, has abundant co-synergistic functional units and unique delayed diffusion and anti-desolvation effects, and shows excellent coke oven gas tri-reforming synthesis gas activity and stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental catalysis and carbon neutrality, and specifically relates to a high-entropy oxide-derived nickel-based catalyst, a preparation method, and a coke oven gas tertiary reforming application. Background Art

[0002] As the main industrial by-product gas in the coking process, coke oven gas will directly produce CO2 emissions when used as fuel, which is contrary to the dual carbon goals. The clean and efficient use of coke oven gas is not only a national environmental protection strategic need, but its comprehensive utilization products (such as high-purity H2 and synthesis gas) also further alleviate the urgent needs of steelmaking and enriching the downstream market. Coke oven gas contains a large amount of H2 (55% to 60%) and CH4 (23% to 27%), and also contains a small amount of CO (5% to 8%), CO2 (1.5% to 3%), O2 (0.3% to 0.8%), N2 (3% to 7%) and other components. Using multiple components in coke oven gas as reaction raw materials and captured CO2 to produce high-quality synthesis gas through reforming reaction can not only reduce direct carbon emissions, but also maximize the utilization of resources. It is a positive measure for green, low-carbon and sustainable development in the coke and steel industries that conforms to national conditions.

[0003] The core reaction of the coke oven gas reforming process to produce synthesis gas is mainly the triple reforming of CH4 and CO2-H2O-O2, that is, the three reactions of CO2 dry reforming (DRM), steam reforming (SRM) and partial oxidation (POM) of methane are carried out simultaneously in one reactor. At present, the focus of the triple reforming process research is to develop efficient and stable reforming reaction catalysts. Ni-based catalysts have great industrial application prospects due to their high catalytic activity and low cost. However, under high temperature reactions, Ni-based catalysts are still prone to thermodynamic sintering, rapid carbon deposition and metal site oxidation, which reduces the reaction performance of the catalyst. At present, two effective methods to improve anti-carbon deposition are to improve the electronic effect and redox effect of metal sites.

[0004] First, the strong electronic interaction between the catalyst surface and the reactant molecules can significantly affect the relative energy levels and the strength of molecular orbital coupling between the reactants / intermediates and the active sites of the catalyst. Therefore, the electron-rich state on the nickel-based catalyst can promote the adsorption and activation of CH4 and the dissociation of the CH bond. For the dilemma of easy deposition of carbon intermediates, improving the oxygen transport / overflow capacity of the catalyst interface is an effective solution. By driving the migration and desorption of oxygen, the CO bond in CO2 is enhanced, thereby activating the catalytic cycle and rapidly removing carbon. In addition, the excessive oxidation of metallic Ni sites by O2 during the triple reforming process is also one of the main reasons for the slow deactivation of the catalyst. If a suitable redox additive can be introduced around the metal site, the impact of oxygen species on the metal Ni site can be absorbed through the variable valence cycle of the additive to maintain its stable activity.

[0005] Combining the advantages of strong electronic effect and redox properties can more effectively improve the decomposition performance of CH4 and CO2 in coke oven gas; however, while maintaining the stability of the material structure and ensuring multifunctional synergistic enhancement, it is undoubtedly a huge challenge to construct functional catalysts while introducing various elements with strong electronic effect and redox properties.

[0006] An effective creative solution is to adopt an isomorphic substitution strategy for the active oxide species of the catalyst, and introduce multiple metal ions of similar size or covalent charge into the same crystal structure of the active oxide through atomic-level regulation to form high-entropy oxides with rich regionalized co-synergistic functional units, in which multiple functional sites can synergistically improve the catalytic performance. In addition, high-entropy oxides are a single-phase multi-component oxide driven by the high-entropy effect, with significant lattice distortion, delayed diffusion and multi-element composite cocktail effects. Due to the differences in electronegativity, ionic radius and coordination ability of different elements, high-entropy oxides usually have a large number of surface defects and multiple functional sites, which give them excellent catalytic performance. At the same time, the unique delayed diffusion effect of the high-entropy oxide framework inhibits the migration and desolvation of metal sites under high temperature or oxidizing environment, and its structural stability and catalytic stability will also be significantly improved.

[0007] Based on this, a nickel-based catalyst derived from a high-entropy oxide of a synergistic functional unit that can couple electronic effects and enhance redox effects was synthesized, which can efficiently and synergistically enhance the activity of coke oven gas to produce synthesis gas in the tertiary reforming process and maintain its catalytic stability. Summary of the invention

[0008] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a high-entropy oxide-derived nickel-based catalyst and a preparation method thereof that couples strong electronic and redox synergistic functional units. The catalyst material is simple to prepare, has abundant synergistic functional units and unique delayed diffusion and anti-dissolution effects, so that it exhibits excellent activity and stability in the tertiary reforming of coke oven gas to produce synthesis gas.

[0009] To achieve the above object, the technical solution of the present invention is as follows:

[0010] On the one hand, the present invention provides a high-entropy oxide-derived nickel-based catalyst, and the chemical composition of the high-entropy oxide-derived nickel-based catalyst is (ABCD-Ni)O, wherein A is one of the metal elements Mg, Ca, Sr, and Ba, which serves as a strong electron donor; B is one of the metal elements Fe, Co, and Cu, which serves as an alloying aid; C is one of the metal elements V, Cr, Mn, Mo, and Fe, which serves as a redox aid; D is one of the metal elements Zr, Y, Ce, and La, which serves as an oxygen vacancy generation source; and the high-entropy oxides all include Ni.

[0011] Furthermore, the high entropy oxide-derived nickel-based catalyst has worm-like mesoporous channels with a mesopore diameter of 6 to 15 nm and a pore volume of 0.5 to 0.9 cm 3 g -1 , with a specific surface area of ​​130 to 200 m 2 g -1 The average particle size of the activated metal particles is 2-6 nm. Each crystal phase of the high entropy oxide is an amorphous structure, and each metal element is highly nano-sized and evenly distributed.

[0012] Furthermore, in the high entropy oxide derived nickel-based catalyst, the nickel phase is 18-22 at.%, the A metal element phase is 18-22 at.%, the B metal element phase is 18-22 at.%, the C metal element phase is 18-22 at.%, and the D metal element phase is 18-22 at.%.

[0013] Another aspect of the present invention provides a method for preparing the high entropy oxide-derived nickel-based catalyst as described above, using an isomorphous substitution solid solution phase synthesis strategy, comprising the following steps:

[0014] (1) Mixing soluble salts of active metals A, B, C, D and Ni and an organic structure directing agent and dissolving them in distilled water to obtain a mixed salt solution a; dissolving a soluble alkali in distilled water to obtain a solution b;

[0015] (2) mixing salt solution a and solution b and precipitating them in parallel, stirring and maintaining the temperature at 30-80° C. and pH=9.5-10 during the precipitation process; aging for 3-7 hours after the precipitation is completed, then washing with distilled water and centrifuging, and placing the precipitated product obtained by centrifugation for 5-24 hours;

[0016] (3) heating the slurry after the precipitation product and distilled water are uniformly stirred until the slurry boils and generates a large amount of bubbles, and heating and refluxing for 24 to 72 hours; cooling the slurry after heating to room temperature, washing with distilled water, and centrifuging until the pH is neutral; then drying and calcining the precipitate obtained by centrifugation to obtain a high entropy oxide material;

[0017] (4) Reducing the high entropy oxide material to obtain the high entropy oxide-derived nickel-based catalyst.

[0018] Further, in the step (1), in the step (1), the soluble salt of active metal A is nitrate, sulfate or hydrochloride of Mg, Ca, Sr or Ba, the soluble salt of active metal B is nitrate, sulfate or hydrochloride of Fe, Co or Cu, the soluble salt of active metal C is nitrate, sulfate, hydrochloride or metal acid salt of V, Cr, Mn, Mo or Fe, the soluble salt of active metal D is nitrate, sulfate or hydrochloride of Y, Ce or La; the organic structure directing agent is glucose , citric acid, oxalic acid and tartaric acid; the soluble base is one of sodium hydroxide, sodium carbonate and potassium hydroxide; the molar ratio of the active metals A, B, C, D and the soluble salt of Ni is 0.9-1.1:0.9-1.1:0.9-1.1:0.9-1.1:0.9-1.1; the total metal concentration of the mixed salt solution a is 0.3-0.9 mol / L; the concentration of solution b is 0.5-2.0 mol / L; the molar ratio of the total metal molar amount in the mixed salt solution a to the organic structure directing agent is 1:0.5-2.

[0019] Furthermore, in the step (2), the stirring speed is 700 to 1100 r / min.

[0020] Furthermore, in step (3), the total concentration of mixed metals in the slurry is 0.5 to 3.0 mol / L; the heating temperature is 125 to 185° C.; the drying temperature is 80 to 120° C., and the time is 12 to 24 hours; and the calcination temperature is 600 to 800° C., and the time is 3 to 6 hours.

[0021] Furthermore, in step (4), the reduction conditions are: pressure 1 atm, reducing atmosphere is H2 / N2 mixed gas, gas space velocity GHSV 2 to 96 L·g -1 ·h -1 , firstly increase the temperature to 400 / 500 / 600 / 700°C at 1-5°C / min and then heat at a constant temperature for 1-2h, then continue to increase the temperature to 800°C at 1-5°C / min and then heat at a constant temperature for 1-2h. The high entropy oxide material of the present invention is used as a catalyst. Before the coke oven gas tertiary reforming reaction, in order to ensure the metal activation state, the active metal and alloying additive of the catalyst still need to be reduced and activated. Under the reduction condition, the in-situ high active dissolution of highly nano-sized nickel sites and the anti-sintering effect during the reaction can be achieved.

[0022] The principle of the synthesis of the material of the present invention is: in the preparation process of the high entropy oxide catalyst of the co-synergistic unit of the material of the present invention, the following necessary conditions must be met: (1) to ensure the solid solution reaction between five or more metal elements to form a single-phase structure; (2) to ensure that each functional element is evenly distributed at the atomic level to form a regionalized functional unit and exert the synergistic effect of the multifunctional site; (3) to control the stable configuration of the metal element to avoid metal migration and desolvation under actual application conditions, so that its structure and catalytic stability cannot be maintained. Therefore, the design idea of ​​the present invention is to introduce the multifunctional element into the amorphous structure NiO skeleton with strong compatibility through the isomorphous substitution strategy.

[0023] On the other hand, the present invention also provides the use of the high entropy oxide-derived nickel-based catalyst as described above in the tertiary reforming of coke oven gas to produce synthesis gas.

[0024] Furthermore, the method comprises the following steps: using a plug flow fixed bed reactor, filling a reaction tube with catalyst particles of 20 to 80 meshes, using a catalyst amount of 0.1 to 5 g, a reaction temperature of 700 to 850° C., a reaction pressure of 1 atm, a reaction gas inlet ratio of CH4:CO2:H2O:O2=1:(1 to 0.7):(0.01 to 0.3):(0.1 to 0.2), and a reaction space velocity of 24,000 to 60,000 mL / (h·g).

[0025] The high entropy oxide-derived nickel-based catalyst synthesized in the present invention has excellent methane and carbon dioxide conversion rates and outstanding anti-sintering, anti-carbon deposition and anti-oxidation properties. When used in the tertiary reforming of coke oven gas to produce synthesis gas, the catalyst shows 100% O2 and H2O conversion rates, and the CH4 and CO2 conversion rates maintain high stability for at least 200 hours, and will not change the specific characteristics of the catalyst such as the particle size or porosity.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) In the process of aging of the metal component, the present invention further mixes and homogenizes the multi-oxide components in the material by continuously refluxing the solution, and promotes the transformation of the solid solution material into an amorphous crystalline state to form an amorphous high entropy oxide, which has a specific short-range ordered crystal structure, but exists in a long-range disordered state, which is more conducive to the uniform mixing of the multifunctional elements with differences to form a single phase and can play a synergistic role in the regionalized functional unit. In addition, the reflux process can make the high entropy oxide material have a unique pore manufacturing effect, and finally form a highly amorphous nano high entropy oxide with a high specific surface area and rich three-dimensional cross-mesoporous structure. The rich three-dimensional cross-mesoporous structure can constitute a spatial confinement effect, which prevents the aggregation of active components in the form of a physical barrier, avoids the loss of active sites, and enhances catalytic stability.

[0028] (2) The material of the present invention forms a single-phase solid solution structure driven by the high configuration entropy effect, and the substitution of differentiated multi-metal elements may lead to significant structural and lattice distortion at the atomic level. However, under the conditions of different sizes of metal elements and the presence of oxygen vacancies, a strain network of regionalized compressive strain and tensile strain is formed, and these two strains should appear in pairs. The oxygen vacancy defects with lattice contraction effect and the large-sized metal ions that trigger structural expansion are adjacent. While maintaining the stability of the overall solid solution phase, the regionalized multifunctional sites can play a synergistic effect. At the same time, its significant lattice distortion produces many electronic defects and surface dislocations, which further promote the formation of oxygen vacancies and the exposure of active sites, increase the overall surface electron density to promote the adsorption and activation of reactant molecules, and thus increase the reaction rate. In addition, the delayed diffusion effect can effectively inhibit the sintering and deactivation of the catalyst at high temperature, maintain the stability of its active sites, and provide a strong guarantee for the continuous and efficient progress of the reaction.

[0029] (3) Atom-specific selection. Based on multiple considerations such as functionality, ionic radius similarity, valence compatibility, and thermodynamic stability, metal elements with similar characteristics to NiO are selected to replace Ni sites to form multi-metal functional units. +2 alkaline earth metals are selected as strong electron donors to replace part of the Ni 2+ sites, and V, Cr, Mn, Mo, and Fe with a radius similar to that of Ni ions are introduced as redox metal additives. However, it is worth noting that the various elements introduced inevitably have differences in charge and size. In order to solve this problem, we further introduced high-valent metals Zr, Y, Ce, and La to replace some Ni sites, generating a large number of oxygen vacancies under the condition of unsaturated oxygen coordination. At the same time, a variety of variable-valence and easily alloyed metal elements such as Fe, Co, and Cu act as auxiliary electronic additive components, compensating for charge differences and size differences of compatible metals through their adjustable valence states and oxygen vacancies. The material as a whole shows a high tolerance to changes in cationic charge and size, the so-called "relaxation effect". This strategy greatly enhances the ability to mix multiple elements in high-entropy oxides, indicating that a stable high-entropy oxide structure can be formed.

[0030] (4) Introducing organic structure-directing agents as promoters of isomorphic substitution. First, organic substances form stable chelates with various metal cations through carboxylic acid groups (-COOH) or hydroxyl groups (-OH) to prevent metal ions from separating in the solution due to hydrolysis or precipitation. Chelation allows different metal ions to be evenly distributed at the atomic scale, avoiding local enrichment or segregation in the precursor solution. During high-temperature calcination, the complexation of organic acids will also slow down the migration rate of metal ions, inhibit the tendency of each metal oxide to form a separate phase, promote the formation of a multi-metallic eutectic lattice, and lay the foundation for the uniformity of the final product. In addition, during high-temperature calcination, the carbon framework of the coating layer formed by in-situ pyrolysis of organic ligands in an inert atmosphere anchors the metal oxides. As an isolation layer, it restricts the growth of metal oxides and prevents the doped metal oxide species from nucleating separately and freeing the eutectic structure. Finally, the carbon framework is removed in an air atmosphere and the oligomeric distribution of isomorphic high-entropy oxides is achieved.

[0031] (5) The reduction activation process of the present invention adopts staged reduction so that the metal sites are dissolved in situ at low temperature to form a large number of metal particles distributed in a highly dispersed sub-nanometer size state of 1 to 4 nm. In the subsequent low-temperature constant temperature stage, the residual oxide functional carrier continues to form a strong metal-carrier interaction with the dissolved metal particles, and can form a layer of thin film "armor" on the outer interface of the sub-nanometer-sized metal particles, so that the metal particles will not grow again or sinter during the subsequent 800°C reduction and triple reforming reaction process; at the same time, as a passivation layer, it can effectively prevent the active sites inside the metal particles from being oxidized by oxygen species.

[0032] (6) The material of the present invention forms an atomic-level functional unit with coexistence of multiple element regions on a single-phase structure. This synergistic unit optimizes the reaction path of coke oven gas triple reforming through multiple functional sites such as multi-metal sites, metal-oxygen-metal electronic polarity gradients and oxygen vacancy enriched areas: the electronic additives in the high entropy oxide structure enhance the strong electronic interaction between the catalyst surface and the reactant molecules, significantly affecting the relative energy levels and the strength of molecular orbital coupling between the reactants / intermediates and the catalyst active sites, thereby promoting the adsorption activation of CH4 and the dissociation of CH bonds. For the dilemma of easy deposition of carbon intermediates, the rich oxygen vacancies of high entropy oxides can serve as a "transient oxygen pump" for CO2 decomposition / transmission of O species, thereby improving the oxygen transmission / overflow capacity of the catalyst interface, and promoting the breaking of CO bonds in CO2 by driving the migration and desorption of oxygen, activating the catalytic cycle and rapidly removing carbon. The redox additives introduced around the metal sites can absorb the impact of oxygen species on the metal Ni sites through the variable valence cycle of the additives, prevent the excessive oxidation of the metal sites by the O2 component, and maintain the stable activity of the metal. In addition, high entropy oxides can form stably anchored highly dispersed Ni-based alloy sites through the dissolution process at different reduction temperatures. These sites are protected by the structure of other oxide skeletons and can be highly tolerant to the presence of H2O, maintaining the long-term reaction stability of the catalyst for more than 200 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the step-by-step reduction strategy of the catalyst of the present invention.

[0034] Figure 2 Long-term evaluation diagram of the catalyst of Example 1 of the present invention.

[0035] Figure 3 Geometric phase analysis picture of the catalyst of Example 3 of the present invention.

[0036] Figure 4 Crystalline phase analysis spectra of the catalyst of Example 6 of the present invention after calcination and step-by-step reduction. DETAILED DESCRIPTION

[0037] The technical scheme of the present invention is further illustrated and described below through examples. However, the protection scope of the present invention is not limited to the following examples.

[0038] Example 1

[0039] Magnesium nitrate (A), cobaltous nitrate (B), manganese nitrate (C), zirconium nitrate (D) and nickel nitrate were mixed in a metal molar ratio of A:B:C:D:Ni=1:1:1:1:1 to prepare a mixed salt solution with a total metal concentration of 0.3 mol / L, and glucose 0.5 times the molar amount of the total metal molar amount of the mixed salt solution was added to completely dissolve, which was recorded as mixed salt solution a; 0.5 mol / L potassium hydroxide aqueous solution was prepared, which was recorded as solution b. At a crystallization temperature of 60°C, solution a and solution b were titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker was controlled to be maintained at 9.5-10, and the stirring speed was 700r / min. After the dripping, the obtained slurry was stirred and aged for 6 hours, and then washed with distilled water and centrifuged until the pH was neutral, and the precipitated product obtained by centrifugation was placed for 10 hours. The precipitated product was mixed with an appropriate amount of distilled water and then prepared into a slurry with a total concentration of mixed metals of 0.5 mol / L and placed in a round-bottom flask. The slurry was then heated to 125°C in an oil bath until the slurry boiled and produced a large amount of bubbles. The slurry was heated to reflux for 24 hours. After the heating was completed, the slurry was cooled to room temperature and washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 100°C for 12 hours and calcined at 600°C in an air atmosphere for 4 hours to obtain a high entropy oxide material of (Mg1Co1Mn1Zr1Ni1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 2L·g -1 ·h -1 , the temperature was raised to 400℃ at 1℃ / min and then kept at constant temperature for 1h, then continued to be raised to 800℃ at 1℃ / min and kept at constant temperature for 1h, and after reduction, a high entropy oxide-derived nickel-based catalyst 1 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 1 is A metal element phase: 18at.%, B metal element phase: 18at.%, C metal element phase: 18at.%, D metal element phase: 22at.%, nickel phase: 20at.%, the average metal particle size is 2.15nm, the mesopore size is 10.6nm, and the pore volume is 0.51cm 3 g -1 , with a specific surface area of ​​184m 2 g -1 .

[0040] Catalyst 1 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 20-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 0.1 g, the reaction temperature was 700°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:0.7:0.01:0.1, the reaction space velocity was 24000 mL / (h·g), and the reaction time was 200 h. The evaluation results are shown in Table 1 and Figure 2 .

[0041] Example 2

[0042] Calcium nitrate (A), ferrous nitrate (B), chromium nitrate (C), lanthanum nitrate (D) and nickel nitrate were mixed in a metal molar ratio of A:B:C:D:Ni=0.9:1.1:0.9:1.1:1 to prepare a mixed salt solution with a total metal concentration of 0.5 mol / L, and 0.5 times the molar amount of oxalic acid in the total metal molar amount of the mixed salt solution was added to completely dissolve, which was recorded as mixed salt solution a; 0.5 mol / L sodium hydroxide aqueous solution was prepared, which was recorded as solution b. At a crystallization temperature of 80°C, solution a and solution b were titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker was controlled to be maintained at 9.5-10, and the stirring speed was 800r / min. After the dripping, the obtained slurry was stirred and aged for 7 hours, and then washed with distilled water and centrifuged until the pH was neutral, and the precipitated product obtained by centrifugation was placed for 24 hours. The precipitated product was mixed with an appropriate amount of distilled water to form a slurry with a total concentration of mixed metals of 1.5 mol / L and placed in a round-bottom flask. The slurry was then heated to 125°C in an oil bath until the slurry boiled and produced a large amount of bubbles. The slurry was heated to reflux for 72 hours. After the slurry was cooled to room temperature, it was washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 120°C for 24 hours and calcined at 700°C in an air atmosphere for 4 hours to obtain a high entropy oxide material of (Ca0.9Fe1.1Cr0.9La1.1Ni1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 30L·g -1 ·h -1 , the temperature was raised to 500℃ at 1℃ / min and then kept at constant temperature for 1h, then continued to be raised to 800℃ at 1℃ / min and kept at constant temperature for 1h, and after reduction, a high entropy oxide-derived nickel-based catalyst 2 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 2 is A metal element phase: 18at.%, B metal element phase: 22at.%, C metal element phase: 18at.%, D metal element phase: 22at.%, nickel phase: 20at.%, the average metal particle size is 3.22nm, the mesopore size is 12.3nm, and the pore volume is 0.65cm 3 g -1 , with a specific surface area of ​​178m 2 g -1 .

[0043] Catalyst 2 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 30-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 1 g, the reaction temperature was 750°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:1:0.3:0.2, the reaction space velocity was 30000 mL / (h·g), and the reaction time was 200 h. The evaluation results are shown in Table 1.

[0044] Example 3

[0045] The metal molar ratio of strontium nitrate (A), copper nitrate (B), ammonium metavanadate (C), cerium nitrate (D) and nickel sulfate is A: B: C: D: Ni = 1.1: 1.1: 0.9: 0.9: 1, and a mixed salt solution with a total metal concentration of 0.9 mol / L is prepared, and glucose is added in an amount twice the molar amount of the total metal molar amount of the mixed salt solution to completely dissolve, which is recorded as mixed salt solution a; a 2.0 mol / L sodium carbonate aqueous solution is prepared, which is recorded as solution b. At a crystallization temperature of 70°C, solution a and solution b are titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker is controlled to be maintained at 9.5-10, and the stirring speed is 1100r / min. After the dripping is completed, the obtained slurry is stirred and aged for 7 hours, and then washed with distilled water and centrifuged until the pH is neutral, and the precipitated product obtained by centrifugation is placed for 24 hours. The precipitated product was mixed with an appropriate amount of distilled water to form a slurry with a total concentration of mixed metals of 3.0 mol / L and placed in a round-bottom flask. The slurry was then heated to 185°C in an oil bath until the slurry boiled and produced a large amount of bubbles. The slurry was heated to reflux for 24 hours. After the slurry was cooled to room temperature, it was washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 120°C for 24 hours and calcined at 800°C in an air atmosphere for 3 hours to obtain a high entropy oxide material of (Sr1.1Cu1.1V0.9Ce0.9Ni1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 55L·g -1 ·h -1 , the temperature was raised to 500℃ at 3℃ / min and then kept at constant temperature for 1h, then continued to be raised to 800℃ at 5℃ / min and kept at constant temperature for 2h, and after reduction, a high entropy oxide-derived nickel-based catalyst 3 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 3 is A metal element phase: 22at.%, B metal element phase: 22at.%, C metal element phase: 18at.%, D metal element phase: 18at.%, nickel phase: 20at.%, the average metal particle size is 5.95nm, the mesopore size is 15.3nm, and the pore volume is 0.67cm 3 g -1 , with a specific surface area of ​​158m 2 g-1 .

[0046] The geometric phase analysis (GPA) images of catalyst 3 are shown in Figure 3 As can be seen from the figure, the material forms a single-phase solid solution structure driven by the high configuration entropy effect, and the substitution of differentiated multi-metal elements causes significant structural and lattice distortion at the atomic level, forming a strain network with regionalized compressive strain and tensile strain interlaced.

[0047] Catalyst 3 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 50-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 2 g, the reaction temperature was 800°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:0.8:0.2:0.2, the reaction space velocity was 40000 mL / (h·g), and the reaction time was 200 h. The evaluation results are shown in Table 1.

[0048] Example 4

[0049] The metal molar ratio of barium nitrate (A), cobalt sulfate (B), iron nitrate (C), yttrium nitrate (D) and nickel nitrate is A: B: C: D: Ni = 1: 0.9: 1.1: 0.9: 1.1 to prepare a mixed salt solution with a total metal concentration of 0.5 mol / L, and tartaric acid 0.5 times the molar amount of the total metal molar amount of the mixed salt solution is added to completely dissolve, which is recorded as mixed salt solution a; 1 mol / L potassium hydroxide aqueous solution is prepared, which is recorded as solution b. At a crystallization temperature of 80°C, solution a and solution b are titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker is controlled to be maintained at 9.5-10, and the stirring speed is 850r / min. After the dripping is completed, the slurry is stirred and aged for 3 hours, and then washed with distilled water and centrifuged until the pH is neutral, and the precipitated product obtained by centrifugation is placed for 5 hours. The precipitated product was mixed with an appropriate amount of distilled water and then prepared into a slurry with a total concentration of mixed metals of 2 mol / L and placed in a round-bottom flask. The slurry was then heated to 140°C using a heating mantle until it boiled and produced a large amount of bubbling. The slurry was heated to reflux for 36 hours. After the heating was completed, the slurry was cooled to room temperature and washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 80°C for 24 hours and calcined at 800°C in an air atmosphere for 3 hours to obtain a high entropy oxide material of (Ba1Co0.9Fe1.1Y0.9Ni1.1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 96L·g -1 ·h -1, the temperature was raised to 600℃ at 3℃ / min and then kept at constant temperature for 2h, then continued to be raised to 800℃ at 5℃ / min and kept at constant temperature for 2h, and after reduction, a high entropy oxide-derived nickel-based catalyst 4 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 4 is A metal element phase: 20at.%, B metal element phase: 18at.%, C metal element phase: 22at.%, D metal element phase: 18at.%, nickel phase: 22at.%, the average metal particle size is 6.11nm, the mesopore size is 17.2nm, and the pore volume is 0.87cm 3 g -1 , with a specific surface area of ​​143m 2 g -1 .

[0050] Catalyst 4 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 80-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 5 g, the reaction temperature was 850°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:1:0.05:0.15, the reaction space velocity was 30000 mL / (h·g), and the reaction time was 250 h. The evaluation results are shown in Table 1.

[0051] Example 5

[0052] Magnesium nitrate (A), cobalt nitrate (B), molybdenum nitrate (C), zirconium nitrate (D) and nickel chloride were mixed in a metal molar ratio of A:B:C:D:Ni=1.1:1:1:1:0.9 to prepare a mixed salt solution with a total metal concentration of 0.6 mol / L, and 0.5 times the molar amount of citric acid of the total metal molar amount of the mixed salt solution was added to completely dissolve, which was recorded as mixed salt solution a; 0.5 mol / L sodium carbonate aqueous solution was prepared, which was recorded as solution b. At a crystallization temperature of 30°C, solution a and solution b were titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker was controlled to be maintained at 9.5-10, and the stirring speed was 700r / min. After the dripping, the obtained slurry was stirred and aged for 5 hours, and then washed with distilled water and centrifuged until the pH was neutral, and the precipitated product obtained by centrifugation was placed for 12 hours. The precipitated product was mixed with an appropriate amount of distilled water and then prepared into a slurry with a total concentration of mixed metals of 0.5 mol / L and placed in a round-bottom flask. The slurry was then heated to 130°C using a heating jacket, and then boiled and a large amount of bubbles were generated. The slurry was heated to reflux for 24 hours. After the heating was completed, the slurry was cooled to room temperature and washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 100°C for 12 hours and calcined at 600°C in an air atmosphere for 4 hours to obtain a high entropy oxide material of (Mg1.1Co1Mo1Zr1Ni0.9)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 70L·g -1 ·h -1 , the temperature was raised to 600℃ at 1℃ / min and then kept at constant temperature for 2h, then continued to be raised to 800℃ at 5℃ / min and kept at constant temperature for 2h, and after reduction, a high entropy oxide-derived nickel-based catalyst 5 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 5 is A metal element phase: 22at.%, B metal element phase: 20at.%, C metal element phase: 20at.%, D metal element phase: 20at.%, nickel phase: 18at.%, the average metal particle size is 5.25nm, the mesopore size is 14.78nm, and the pore volume is 0.63cm 3 g -1 , with a specific surface area of ​​162m 2 g -1 .

[0053] Catalyst 5 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 50-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 3 g, the reaction temperature was 800°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:0.9:0.2:0.1, the reaction space velocity was 60000 mL / (h·g), and the reaction time was 300 h. The evaluation results are shown in Table 1.

[0054] Example 6

[0055] Calcium nitrate (A), cobalt nitrate (B), iron nitrate (C), zirconium nitrate (D) and nickel nitrate were mixed in a metal molar ratio of A:B:C:D:Ni=1:1:1:1:1 to prepare a mixed salt solution with a total metal concentration of 0.3 mol / L, and oxalic acid 1.5 times the total metal molar amount of the mixed salt solution was added to completely dissolve, which was recorded as mixed salt solution a; 0.5 mol / L sodium hydroxide aqueous solution was prepared, which was recorded as solution b. At a crystallization temperature of 50°C, solution a and solution b were titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker was controlled to be maintained at 9.5-10, and the stirring speed was 850r / min. After the dripping was completed, the obtained slurry was stirred and aged for 7 hours, and then washed with distilled water and centrifuged until the pH was neutral, and the precipitated product obtained by centrifugation was placed for 10 hours. The precipitated product was mixed with an appropriate amount of distilled water to form a slurry with a total concentration of mixed metals of 0.5 mol / L and placed in a round-bottom flask. The slurry was then heated to 125°C in an oil bath until the slurry boiled and produced a large amount of bubbles. The slurry was heated to reflux for 72 hours. The slurry was cooled to room temperature and washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 120°C for 24 hours and calcined at 800°C in an air atmosphere for 3 hours to obtain a high entropy oxide material of (Ca1Co1Fe1Zr1Ni1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity was GHSV65L·g -1 ·h -1 , the temperature was raised to 500℃ at 1℃ / min and then kept at constant temperature for 2h, then continued to be raised to 800℃ at 5℃ / min and kept at constant temperature for 2h, and after reduction, a high entropy oxide-derived nickel-based catalyst 6 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 6 is A metal element phase: 20at.%, B metal element phase: 20at.%, C metal element phase: 20at.%, D metal element phase: 20at.%, nickel phase: 20at.%, the average metal particle size is 4.98nm, the mesopore size is 13.88nm, and the pore volume is 0.58cm 3 g -1 , with a specific surface area of ​​167m 2 g -1 .

[0056] Figure 4This is the crystal phase analysis spectrum of (Ca1Co1Fe1Zr1Ni1)O high entropy oxide catalyst after calcination and step-by-step reduction. The calcined sample presents a highly nano-sized amorphous structure, with the main crystal phases being tetragonal ZrO2 and NiO with a relatively high diffraction width; after subsequent step-by-step reduction, the catalyst still has a highly broadened XRD peak, and no diffraction peaks of Ca, Co, and Fe elements appear. According to the Scherrer formula, the Ni species particle size is 1.9nm, indicating that Ni exists in a highly dispersed sub-nanometer size state after reduction activation.

[0057] Catalyst 6 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 20-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 0.3 g, the reaction temperature was 700°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:0.8:0.3:0.2, the reaction space velocity was 24000 mL / (h·g), and the reaction time was 200 h. The evaluation results are shown in Table 1.

[0058] Example 7

[0059] Calcium nitrate (A), ferrous nitrate (B), chromium nitrate (C), cerium nitrate (D) and nickel sulfate were mixed in a metal molar ratio of A:B:C:D:Ni=0.9:1.1:0.9:1.1:1 to prepare a mixed salt solution with a total metal concentration of 0.5 mol / L, and citric acid twice the molar amount of the total metal molar amount of the mixed salt solution was added to completely dissolve, which was recorded as mixed salt solution a; 0.5 mol / L potassium hydroxide aqueous solution was prepared, which was recorded as solution b. At a crystallization temperature of 70°C, solution a and solution b were titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker was controlled to be maintained at 9.5-10, and the stirring speed was 700r / min. After the dripping, the obtained slurry was stirred and aged for 3 hours, and then washed with distilled water and centrifuged until the pH was neutral, and the precipitated product obtained by centrifugation was placed for 24 hours. The precipitated product was mixed with an appropriate amount of distilled water to form a slurry with a total concentration of mixed metals of 1.5 mol / L and placed in a round-bottom flask. The slurry was then heated to 140°C in an oil bath until the slurry boiled and produced a large amount of bubbles. The slurry was heated to reflux for 72 hours. The slurry was cooled to room temperature and washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 80°C for 24 hours and calcined at 800°C in an air atmosphere for 3 hours to obtain a high entropy oxide material of (Ca0.9Fe1.1Cr0.9Ce1.1Ni1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 55L·g -1 ·h -1, the temperature was raised to 500℃ at 1℃ / min and then kept at constant temperature for 1h, then continued to be raised to 800℃ at 1℃ / min and kept at constant temperature for 1h, and after reduction, a high entropy oxide-derived nickel-based catalyst 7 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 7 is A metal element phase: 18at.%, B metal element phase: 22at.%, C metal element phase: 18at.%, D metal element phase: 22at.%, nickel phase: 20at.%, the average metal particle size is 2.77nm, the mesopore size is 11.6nm, and the pore volume is 0.50cm 3 g -1 , with a specific surface area of ​​188m 2 g -1 .

[0060] Catalyst 7 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 20-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 0.1 g, the reaction temperature was 700°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:1:0.02:0.15, the reaction space velocity was 24000 mL / (h·g), and the reaction time was 100 h. The evaluation results are shown in Table 1.

[0061] Example 8

[0062] Magnesium sulfate (A), cobalt nitrate (B), iron nitrate (C), zirconium nitrate (D) and nickel nitrate were mixed in a metal molar ratio of A:B:C:D:Ni=1:1:1:0.9:1.1 to prepare a mixed salt solution with a total metal concentration of 0.9 mol / L, and tartaric acid 1.5 times the total metal molar amount of the mixed salt solution was added to completely dissolve, which was recorded as mixed salt solution a; 2 mol / L sodium hydroxide aqueous solution was prepared, which was recorded as solution b. At a crystallization temperature of 80°C, solution a and solution b were titrated into a large beaker by co-current titration while stirring, and the pH of the bottom liquid in the large beaker was controlled to be maintained at 9.5-10, and the stirring speed was 1100r / min. After the dripping, the obtained slurry was stirred and aged for 5h, and then washed with distilled water and centrifuged until the pH was neutral, and the precipitated product obtained by centrifugation was placed for 24h. The precipitated product was mixed with an appropriate amount of distilled water and then prepared into a slurry with a total concentration of mixed metals of 3 mol / L and placed in a round-bottom flask. The slurry was then heated to 180°C in an oil bath until it boiled and produced a large amount of bubbles. The slurry was heated to reflux for 36 hours. After the heating was completed, the slurry was cooled to room temperature and washed with distilled water and centrifuged several times until the pH was neutral. The slurry was dried at 100°C for 12 hours and calcined at 600°C in an air atmosphere for 4 hours to obtain a high entropy oxide material of (Mg1Co1Fe1Zr0.9Ni1.1)O. The obtained high entropy oxide material was at a pressure of 1atm in the reduction tube, the reducing atmosphere was a H2 / N2 mixed gas, and the gas space velocity GHSV was 80L·g -1 ·h -1 , the temperature was raised to 600℃ at 3℃ / min and then kept at constant temperature for 2h, then continued to be raised to 800℃ at 5℃ / min and kept at constant temperature for 1h, and after reduction, a high entropy oxide-derived nickel-based catalyst 8 with coupled strong electronic and redox synergistic functional units was obtained. The actual composition of catalyst 8 is A metal element phase: 20at.%, B metal element phase: 20at.%, C metal element phase: 20at.%, D metal element phase: 18at.%, nickel phase: 22at.%, the average metal particle size is 5.68nm, the mesopore size is 15.28nm, and the pore volume is 0.63cm 3 g -1 , with a specific surface area of ​​151m 2 g -1 .

[0063] Catalyst 8 was used for the tertiary reforming of coke oven gas to produce synthesis gas: a plug flow fixed bed reactor was used, 50-mesh catalyst particles were used to fill the reaction tube, the amount of catalyst was 3 g, the reaction temperature was 800°C, the reaction pressure was 1 atm, the reaction gas ratio was CH4:CO2:H2O:O2=1:1:0.3:0.2, the reaction space velocity was 60000 mL / (h·g), and the reaction time was 200 h. The evaluation results are shown in Table 1.

[0064] Table 1 Evaluation results of various catalysts

[0065]

[0066] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. Although the illustrative specific embodiments of the present invention are described above to facilitate the understanding of the present invention by the technical personnel in the field, it should be clear that the present invention is not limited to the scope of the specific embodiments. For the ordinary technical personnel in the field, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A high entropy oxide derived nickel-based catalyst, characterized in that: The chemical composition of the high entropy oxide-derived nickel-based catalyst is (ABCD-Ni)O, wherein A is one of the metal elements Mg, Ca, Sr, and Ba, serving as a strong electron donor; B is one of the metal elements Fe, Co, and Cu, serving as an alloying aid; C is one of the metal elements V, Cr, Mn, Mo, and Fe, serving as a redox aid; D is one of the metal elements Zr, Y, Ce, and La, serving as an oxygen vacancy generation source; and the high entropy oxides all include Ni.

2. A high entropy oxide derived nickel-based catalyst according to claim 1, characterized in that: The high entropy oxide-derived nickel-based catalyst has worm-like mesoporous channels with a mesopore diameter of 6 to 15 nm and a pore volume of 0.5 to 0.9 cm 3 g -1 , with a specific surface area of ​​130 to 200 m 2 g -1 The average particle size of the metal particles after activation is 2 to 6 nm.

3. A high entropy oxide derived nickel-based catalyst according to claim 1, characterized in that: The high entropy oxide derived nickel-based catalyst comprises 18-22 at.% nickel phase, 18-22 at.% A metal element phase, 18-22 at.% B metal element phase, 18-22 at.% C metal element phase, 18-22 at.% D metal element phase and 18-22 at.%.

4. The method for preparing a high entropy oxide-derived nickel-based catalyst according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Mixing soluble salts of active metals A, B, C, D and Ni and an organic structure directing agent and dissolving them in distilled water to obtain a mixed salt solution a; dissolving a soluble alkali in distilled water to obtain a solution b; (2) mixing salt solution a and solution b and precipitating them in parallel, stirring and maintaining the temperature at 30-80° C. and pH=9.5-10 during the precipitation process; aging for 3-7 hours after the precipitation is completed, then washing with distilled water and centrifuging, and placing the precipitated product obtained by centrifugation for 5-24 hours; (3) The slurry obtained by mixing the precipitated product and distilled water is heated until the slurry boils and generates a large amount of bubbles, and then heated under reflux for 24 to 72 hours; after the heating is completed, the slurry is cooled to room temperature, washed with distilled water, and centrifuged until the pH is neutral; Then, the precipitate obtained by centrifugation is dried and calcined to obtain a high entropy oxide material; (4) Reducing the high entropy oxide material to obtain the high entropy oxide-derived nickel-based catalyst.

5. The method for preparing a high entropy oxide-derived nickel-based catalyst according to claim 4, characterized in that: In the step (1), the soluble salt of active metal A is nitrate, sulfate or hydrochloride of Mg, Ca, Sr or Ba, the soluble salt of active metal B is nitrate, sulfate or hydrochloride of Fe, Co or Cu, the soluble salt of active metal C is nitrate, sulfate, hydrochloride or metal acid salt of V, Cr, Mn, Mo or Fe, and the soluble salt of active metal D is nitrate, sulfate or hydrochloride of Y, Ce or La; the organic structure directing agent is glucose, citric acid, oxalic acid and The invention discloses a method for preparing a mixed salt solution of a kind of tartaric acid; the soluble alkali is one of sodium hydroxide, sodium carbonate and potassium hydroxide; the molar ratio of the soluble salt of active metals A, B, C, D and Ni is 0.9-1.1:0.9-1.1:0.9-1.1:0.9-1.1:0.9-1.1; the total metal concentration of the mixed salt solution a is 0.3-0.9 mol / L; the concentration of the solution b is 0.5-2.0 mol / L; the molar ratio of the total metal molar amount in the mixed salt solution a to the organic structure directing agent is 1:0.5-2.

6. The method for preparing a high entropy oxide-derived nickel-based catalyst according to claim 4, characterized in that: In the step (2), the stirring speed is 700-1100 r / min.

7. The method for preparing a high entropy oxide-derived nickel-based catalyst according to claim 4, characterized in that: In the step (3), the total concentration of mixed metals in the slurry is 0.5 to 3.0 mol / L; the heating temperature is 125 to 185°C; the drying temperature is 80 to 120°C, and the time is 12 to 24 hours; the calcination temperature is 600 to 800°C, and the time is 3 to 6 hours.

8. The method for preparing a high entropy oxide-derived nickel-based catalyst according to claim 4, characterized in that: In step (4), the reduction conditions are: pressure 1 atm, reducing atmosphere is H2 / N2 mixed gas, gas space velocity GHSV 2 to 96 L·g -1 ·h -1 , first increase the temperature to 400 / 500 / 600 / 700°C at 1-5°C / min and then heat at a constant temperature for 1-2h, then continue to increase the temperature to 800°C at 1-5°C / min and then heat at a constant temperature for 1-2h.

9. Use of the high entropy oxide-derived nickel-based catalyst according to any one of claims 1 to 3 in the tertiary reforming of coke oven gas to produce synthesis gas.

10. The use of the high entropy oxide derived nickel-based catalyst according to claim 9, characterized in that: The following steps are involved: A plug flow fixed bed reactor is adopted, and a reaction tube is filled with catalyst particles of 20 to 80 meshes. The amount of catalyst used is 0.1 to 5 g, the reaction temperature is 700 to 850° C., the reaction pressure is 1 atm, the reaction gas inlet ratio is CH4:CO2:H2O:O2=1:(1 to 0.7):(0.01 to 0.3):(0.1 to 0.2), and the reaction space velocity is 24000 to 60000 mL / (h·g).

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