Application of high-entropy catalyst in hydrogen production from catalytic reforming of oxygen-containing hydrocarbons

Abstract

The present application relates to the production and manufacturing of biomass gas in new energy industry, solid waste pollution disposal and resource recycling, and particularly relates to application of high-entropy catalyst in catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen. The high-entropy catalyst for catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen has a spinel structure of AB2O4; the B site is a trivalent iron element; the A site is a combination of five or six divalent metal elements from the following group: Mg, Co, Ni, Cu, Zn and Ca; the amount of substance of the trivalent iron element at the B site accounts for 2 / 7 of the total amount of substance of all elements in AB2O4, and the total amount of substance of the five or six divalent metal elements at the A site accounts for 1 / 7 of the total amount of substance of all elements in AB2O4. The spinel structure oxide has a high-entropy effect, which greatly improves the hydrogen production efficiency of the catalyst in oxygen-containing hydrocarbons.

Description

Technical Field

[0001] This invention relates to the fields of biomass gas production and manufacturing in the new energy industry; solid waste pollution disposal and resource recycling; and particularly to the application of a high-entropy catalyst in the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen. Background Technology

[0002] Waste polyolefin plastics include waste polyethylene (high-density and low-density), waste polypropylene, waste polybutene, and waste polypentadiene, with a wide range of sources. Packaging waste, waste agricultural film, and waste electronic equipment are the most common sources of waste polyolefin plastics. In addition, among municipal solid waste, kitchen waste oil is a type of food waste that is difficult to effectively separate mechanically from packaging waste such as polypropylene. Kitchen waste oil mainly consists of cooking vegetable oil and animal fats from food. The most common industrial energy application of kitchen waste oil is through biological treatment to produce biofuels. Due to its low cost and widespread availability, it is considered an important waste resource. Therefore, integrating more advanced energy utilization technologies such as pyrolysis and gasification to develop green and efficient methods for co-treating these energy-intensive municipal solid wastes into gaseous or oily products has attracted considerable attention.

[0003] Developing green and efficient hydrogen production methods using municipal solid waste as feedstock will help enhance the social status and market competitiveness of hydrogen energy, potentially making it an increasingly important player in the global energy structure. However, thermochemical catalytic hydrogen production always requires high temperature and pressure conditions, which places a greater burden on equipment costs and energy consumption. The use of catalysts can lower the activation energy of chemical reactions, allowing the reactions to proceed under milder conditions, thereby increasing the reaction rate, which translates to lower energy consumption and operating costs. However, finding catalysts with high catalytic activity, selectivity, and stability remains a significant challenge, especially considering the unique process conditions and catalytic reaction mechanisms of thermochemical catalytic hydrogen production.

[0004] Currently, finding a hydrogen production catalyst that resists deactivation, has good high-temperature stability, and good catalytic performance has become a new goal for those skilled in the art. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] The present invention aims to at least partially solve one of the above-mentioned technical problems.

[0007] (II) Technical Solution

[0008] The first aspect of this invention provides a high-entropy catalyst for the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen. The high-entropy catalyst of this invention for the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen exhibits... The spinel configuration; the B-site is trivalent iron; the A-site is a combination of five or six divalent metallic elements from the following groups: Mg, Co, Ni, Cu, Zn, Ca; the amount of trivalent iron at the B-site accounts for... The total amount of substance of all elements in the A site is 2 / 7 of the total amount of substance of the five or six divalent metallic elements. It is 1 / 7 of the total amount of substance of all elements in it.

[0009] In some embodiments of the present invention, the high-entropy catalyst exhibits The spinel configuration; among which, The element is a divalent metallic element, selected from any five of the six elements: Mg, Co, Ni, Cu, Zn, and Ca.

[0010] In some embodiments of the present invention, the high-entropy catalyst In the spinel configuration: the A1 position is selected from Mg and Ca; the A2 position is selected from Ni and Zn; the A3 position is selected from Co and Cu; and the A4 and A5 positions are selected from two elements of Mg, Co, Ni, Cu, Zn, and Ca that are different from the elements at the A1, A2, and A3 positions.

[0011] In some embodiments of the present invention The ions are selected from five elements: Co, Ni, Cu, Zn, and Mg, and the amount of each element is the same.

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned high-entropy catalyst. The method for preparing the high-entropy catalyst includes:

[0013] Step A: Mix the salt solution of trivalent iron and the salt solutions of five divalent metal elements, add an alcohol solvent, mix, and obtain a mixed liquid precursor;

[0014] Step B involves hydrothermal treatment of the mixed precursor, followed by centrifugation, washing, drying, and grinding to obtain a solid precursor.

[0015] Step C involves calcining the solid precursor, cooling it, and then grinding it to obtain a high-entropy catalyst.

[0016] In some embodiments of the present invention, in step A, the salt solution is one or more of nitrate solution, chloride solution, and sulfate solution, and the alcohol solvent is one or more of ethanol, ethylene glycol, methanol, propanol, isopropanol, n-butanol, and isobutanol, and the volume of the alcohol solvent is 1.5-2.5 times the volume of water in the salt solution.

[0017] In some embodiments of the present invention, in step B, the temperature of the hydrothermal treatment is 180-200 °C, and the time of the hydrothermal treatment is 8-24 h.

[0018] In some embodiments of the present invention, in step C, calcination is carried out in an air atmosphere, the calcination temperature is 850-1050 °C, the calcination time is 2-8 h, and the air flow rate is 50-200 mL / min.

[0019] In some embodiments of the present invention, in step A, the mixing is carried out by continuous stirring at 25-45°C, with a stirring speed of 300-400 rpm / min and a stirring time of 15-45 min; the precursor of the mixture is a transparent precursor of the mixture.

[0020] In some embodiments of the present invention, in step B, the centrifugation is carried out in a high-speed centrifuge, the number of centrifugations is 6-10, the centrifugation rate is 9000-12000 rap / min, and the centrifugation time is 8-15 min.

[0021] In some embodiments of the present invention, in step B, the number of washing cycles is 6-10, wherein the washing is performed 3-5 times with anhydrous ethanol and then 3-5 times with ultrapure water.

[0022] In some embodiments of the present invention, in step B, drying is carried out in an oven at a temperature between 80-100°C.

[0023] In some embodiments of the present invention, in step C, calcination is carried out in a tube furnace.

[0024] In some embodiments of the present invention, in steps B and C, grinding is carried out in an agate mortar.

[0025] A third aspect of this invention provides the application of the above-mentioned high-entropy catalyst in the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen.

[0026] In some embodiments of the present invention, the reforming is steam reforming; the raw material is a mixture of waste polypropylene and waste cooking oil.

[0027] In some embodiments of the present invention, the application conditions are as follows: the amount of packing material is 0.5-3g or the feed flow rate is 20-100 μL / min, the amount of catalyst is 0.1-1.0 g, the reaction temperature is 700-900 ℃, and the protective gas flow rate is 50-250 mL / min, wherein the protective gas is nitrogen; used for a two-stage gasification-reforming integrated fixed bed.

[0028] (III) Beneficial Effects

[0029] As can be seen from the above technical solution, the present invention has at least one of the following beneficial effects compared to the prior art:

[0030] (1) The composition of high-entropy compounds improves catalytic performance.

[0031] High-entropy oxides (abbreviated as "high-entropy oxides") "" is a special type of multi-component oxide that satisfies a configuration entropy greater than or equal to 1.5R. Its characteristics are mainly reflected in the uniformity of composition and crystal structure. Typically composed of five or more metallic elements, it exhibits higher compositional uniformity and a more complex structure, which provides more possibilities for the diversified performance of catalysts.

[0032] The spinel-structured oxide prepared by this invention exhibits a high-entropy effect, which allows the multi-component components of Fe, Mg, Co, Ni, Cu, Zn, and / or Ca to be distributed more uniformly, rather than concentrated in a certain region. This results in a more balanced interaction between the various metallic elements. This effect makes the prepared... The catalyst exhibits excellent catalytic activity, selectivity, and stability.

[0033] Furthermore, the preparation of the present invention Its various advantages can resist catalyst deactivation through different pathways: excellent high-temperature stability, resistance to metal particle agglomeration, unaffected by temperature fluctuations, and improved resistance to physical wear. The diversity of crystal lattice arrangements can regulate the surface structure and active sites of the catalyst, thereby improving its adsorption and conversion capacity for reactants. This capacity can resist catalyst poisoning and prevent changes in catalyst structure, and also slow down the formation of coke and char.

[0034] (2) Five or six specific elements occupying site A are required to form a high-entropy catalyst.

[0035] Furthermore, if three or four elements, Fe, Ni, Co, and Mg, are used to prepare, for example... According to the definition of high entropy and actual experimental results, this type of spinel oxide catalyst does not possess a high entropy effect, meaning it cannot exhibit the superior catalytic performance brought about by the high entropy effect. Its performance is also far inferior to the high entropy catalyst with five metals forming the A-site proposed in this invention. Or a high-entropy catalyst formed by six metals at site A. .

[0036] (3) The combination of multiple elements improves the hydrogen production efficiency of the catalyst in the mixture of waste polypropylene and kitchen waste oil.

[0037] Among the various elements, Mg and Ca both exhibit alkaline catalytic properties, which can promote the catalytic cracking reactions of organic compounds such as alcohols and ketones to produce hydrogen. Ni and Zn are usually used to catalyze the reforming reactions of hydrocarbon organic compounds to produce hydrogen and lighter carbon hydrocarbons. Co and Cu are often used in water-gas reactions to promote the reaction of CO with water vapor to produce CO2 and H2. They can also promote the catalytic cracking reactions of oxygen-containing organic compounds under higher temperature conditions. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating the preparation method of a high-entropy catalyst for hydrogen production from oxygen-containing hydrocarbons using catalytic reforming, as described in an embodiment of the present invention.

[0039] Figure 2 This is a SEM image of the catalyst HEO1 in Example 1.

[0040] Figure 3 The image shows the XRD pattern of catalyst HEO1 in Example 1.

[0041] Figure 4 The image shows the Raman spectrum of catalyst HEO1 in Example 1.

[0042] Figure 5 This is a TEM-EDS mapping image of catalyst HEO1 from Example 1. Detailed Implementation

[0043] This invention uses spinel Based on its configuration, a high-entropy catalyst designed using trivalent iron as the B site and five or six divalent metals as the A site has the characteristics of high crystal stability and uniform distribution of active sites. It can maintain the integrity of its structure under high temperature and high pressure reaction conditions, thereby improving the catalyst's adsorption and conversion efficiency of reactants. It can be applied to catalytic reforming technology to enhance catalytic hydrogen production performance.

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings.

[0045] The first aspect of this invention provides a high-entropy catalyst for the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen. This high-entropy catalyst exhibits... The spinel configuration. In the configuration of spinel, the B-site is occupied by trivalent iron, and the A-site is occupied by a combination of five or six divalent metallic elements from the following groups: Mg, Co, Ni, Cu, Zn, and Ca. The trivalent iron at the B-site accounts for a certain percentage of the total molar amount of the spinel. The total amount of substance of all elements in the A site is 2 / 7 of the total amount of substance of the five or six divalent metallic elements. It is 1 / 7 of the total amount of substance of all elements in it.

[0046] In a preferred embodiment of the present invention, the high-entropy catalyst exhibits a spinel configuration of (A1A2A3A4A5)B2O4; wherein the single-crystal composition comprises trivalent iron at the B site and five divalent metals at the A site, and the divalent metals are any five combinations selected from divalent magnesium, divalent cobalt, divalent nickel, divalent copper, divalent zinc, or divalent calcium. Among the five divalent metal elements, any five of Mg, Co, Ni, Cu, Zn, and Ca are present in equal amounts.

[0047] In a more preferred embodiment of the present invention The catalyst is composed of five elements: Co, Ni, Cu, Zn, and Mg. The amount of each element accounts for 2 / 70 of the total amount of all elements in the high-entropy catalyst, meaning that the amount of each of the five elements is the same.

[0048] Those skilled in the art should understand that in other embodiments of the present invention, A1 to A5 can also be any five of the above six elements—Mg, Co, Ni, Cu, Zn, and Ca. The amount of each element can be exactly the same or fluctuate within ±10%, as long as the total amount of the five metal elements accounts for 1 / 7 of the total amount of all elements in the high-entropy catalyst, the present invention can be achieved. However, experiments have shown that the catalytic efficiency is highest in catalytic reforming experiments when the amount of metal elements is the same.

[0049] This invention uses spinel This catalyst, based on a high-entropy oxide configuration, utilizes trivalent iron as the B-site and five divalent metals as the A-site. The spinel structure is a special crystal structure, typically composed of four metal ions and six oxygen ions, forming an octahedral coordination structure. The high-entropy spinel catalyst of this invention exhibits high crystal stability, maintaining its structural integrity under high-temperature and high-pressure reaction conditions. The octahedral coordination structure of the metal ions leads to a uniform distribution of active sites. This uniformity helps improve the catalyst's adsorption and conversion efficiency of reactants, enhancing catalytic performance; furthermore, it resists the adsorption of poisoning substances. In summary, the spinel-configured catalyst demonstrates excellent catalytic activity in both gas-phase and liquid-phase catalytic reactions.

[0050] Specifically, in this invention, five or six elemental components are added to improve the high-entropy stability of the catalyst. The metal ions in the structure contain a variety of different elements (such as Mg, Co, Ni, Cu, Zn, Ca, etc.). The flexible design of the multi-elemental component combination has the following beneficial effects:

[0051] (1) The composition of high-entropy compounds improves catalytic performance.

[0052] High-entropy oxides (abbreviated as "high-entropy oxides") HEOs are a special class of multi-component oxides that satisfy a configuration entropy greater than or equal to 1.5R. Their characteristics are mainly reflected in their compositional uniformity and crystal structure. HEOs are usually composed of five or more metallic elements, which gives them higher compositional uniformity and more complex structures, providing more possibilities for the diversified performance of catalysts.

[0053] The spinel-structured oxide prepared by this invention exhibits a high-entropy effect, which allows the multi-component components of Fe, Mg, Co, Ni, Cu, Zn, and / or Ca to be distributed more uniformly, rather than concentrated in a certain region. This results in a more balanced interaction between the various metallic elements. This effect makes the prepared... The catalyst exhibits excellent catalytic activity, selectivity, and stability.

[0054] Furthermore, the preparation of the present invention Its various advantages can resist catalyst deactivation through different pathways: excellent high-temperature stability, resistance to metal particle agglomeration, unaffected by temperature fluctuations, and improved resistance to physical wear. The diversity of crystal lattice arrangements can regulate the surface structure and active sites of the catalyst, thereby improving its adsorption and conversion capacity for reactants. This capacity can resist catalyst poisoning and prevent changes in catalyst structure, and also slow down the formation of coke and char.

[0055] (2) Five or six specific elements occupying site A are required to form a high-entropy catalyst.

[0056] Furthermore, if three or four elements, Fe, Ni, Co, and Mg, are used to prepare, for example... According to the definition of high entropy and actual experimental results, this type of spinel oxide catalyst does not possess a high entropy effect, meaning it cannot exhibit the superior catalytic performance brought about by the high entropy effect. Its performance is also far inferior to the high entropy catalyst with five metals forming the A-site proposed in this invention. Or a high-entropy catalyst formed by six metals at site A. .

[0057] (3) The combination of multiple elements improves the hydrogen production efficiency of the catalyst in the mixture of waste polypropylene and kitchen waste oil.

[0058] Among the various elements, Mg and Ca both exhibit basic catalytic properties, promoting the catalytic cracking of organic compounds such as alcohols and ketones to produce hydrogen. Ni and Zn are commonly used in the reforming of hydrocarbon organic compounds to produce hydrogen and lighter carbon hydrocarbons. Co and Cu are frequently used in water-gas reactions to promote the reaction of CO with water vapor to produce hydrogen. and It can also promote the catalytic cracking reaction of oxygen-containing organic matter under higher temperature conditions.

[0059] In summary, the spinel of this invention The combination of multiple elements in high-entropy oxide catalysts allows for flexible control of catalytic selectivity. They also possess properties such as resistance to poisoning, sintering, and carbon deposition, high temperature resistance, high activity, and long lifespan. They can be applied to catalytic reforming technology to produce high-content hydrogen and can provide stable catalysis over a long period of time.

[0060] A second aspect of the present invention provides a method for preparing a high-entropy catalyst as described above for the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen. Figure 1 This is a flowchart illustrating the preparation method of a high-entropy catalyst for the catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen, as described in this embodiment of the invention. Figure 1 As shown, the preparation method of the high-entropy catalyst for catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen in this embodiment includes:

[0061] Step A: Mix the salt solution of trivalent iron and the salt solutions of five divalent metal elements, add an alcohol solvent, mix, and obtain a mixed liquid precursor;

[0062] Step B involves hydrothermal treatment of the mixed precursor, followed by centrifugation, washing, drying, and grinding to obtain a solid precursor.

[0063] Step C involves calcining the solid precursor, cooling it, and then grinding it to obtain a high-entropy catalyst.

[0064] In some embodiments of the present invention, in step A, the salt solution is one or more of a nitrate solution, a chloride solution, and a sulfate solution. Specifically, the salt solution of trivalent iron is... , , One of the solutions. Five divalent metal elements are selected from any five of Mg, Co, Ni, Cu, Zn, and Ca, and their salt solutions are one of the metal's nitrate, chloride, or sulfate. In the mixed salt solution, the amount of Fe accounts for 2 / 7 of the total amount of all elements in the high-entropy catalyst; the amounts of Mg, Co, Ni, Cu, and Zn each account for 2 / 70 of the total amount of all elements in the high-entropy catalyst.

[0065] In some embodiments of the present invention, in step A, the alcohol solvent is ethanol or ethylene glycol, and its volume is 1.5-2.5 times the volume of water in the salt solution. Mixing is performed by continuous stirring at 25-45°C, at a stirring speed of 300-400 rpm / min, for a stirring time of 15-45 min; the precursor for the mixture is a transparent precursor.

[0066] Those skilled in the art should understand that, in addition to ethanol or ethylene glycol solvents, alcohol solvents can also be methanol, propanol, isopropanol, n-butanol, isobutanol, and other types, which will not be elaborated here.

[0067] In some embodiments of the present invention, in step B, the hydrothermal treatment temperature is 180-200 °C, and the hydrothermal treatment time is 8-24 h. Centrifugation is carried out in a high-speed centrifuge, with 6-10 centrifugations at a speed of 9000-12000 rap / min and a centrifugation time of 8-15 min. Washing is performed 6-10 times, including 3-5 washes with anhydrous ethanol followed by 3-5 washes with ultrapure water. Drying is carried out in an oven at a temperature between 80-100 °C. Grinding is carried out in an agate mortar.

[0068] In some embodiments of the present invention, in step C, calcination is carried out in an air atmosphere at a temperature of 850-1050 °C for 2-8 h, with an air flow rate of 50-200 mL / min. Calcination is performed in a tube furnace. Grinding is carried out in an agate mortar.

[0069] A third aspect of the present invention provides the application of the above-mentioned high-entropy catalyst in the catalytic reforming of oxygen-containing hydrocarbon compounds to produce hydrogen.

[0070] In some embodiments of the present invention, the reforming is steam reforming, and the application conditions are as follows: the amount of packing is 0.5-3g or the feed flow rate is 20-100 μL / min, the amount of catalyst is 0.1-1.0 g, the reaction temperature is 700-900 ℃, and the protective gas flow rate is 50-250 mL / min.

[0071] In some embodiments of the present invention, the raw material for hydrogen production is a mixture of waste polypropylene and kitchen waste oil, the protective gas is nitrogen, and a high-entropy catalyst is used in a two-stage gasification-reforming integrated fixed bed.

[0072] The present invention will be described in more detail below with reference to specific embodiments.

[0073] Example 1

[0074] In this embodiment, the high-entropy catalyst used for catalytic reforming of oxygen-containing hydrocarbons to produce hydrogen is spinel. The high-entropy oxide configuration includes one trivalent iron at the B site and five divalent metals at the A site. The amount of Fe in the catalyst accounts for 2 / 7 of the total amount of all elements in the catalyst, and the amounts of the five divalent metals Co, Ni, Cu, Zn, and Mg each account for 2 / 70 of the total amount of all elements in the catalyst.

[0075] The preparation method of the above catalyst includes the following steps:

[0076] Step S1: Add 0.1 mol of 0.01 mol 0.01 mol 0.01 mol 0.01 mol and 0.01 mol The mixture was added to 50 mL of ultrapure water and stirred at 350 rpm / min for 20 min at room temperature. Then, 100 mL of ethanol and 100 mL of ethylene glycol were added to the solution and stirred at 350 rpm / min for 20 min at room temperature to obtain a transparent solution precursor.

[0077] Step S2: Place the solution precursor into a 500mL polytetrafluoroethylene hydrothermal reactor liner, treat it at 200℃ for 12h, and cool it for 12h to obtain the hydrothermally treated precursor.

[0078] Step S3: The hydrothermally treated precursor was centrifuged at 10,000 rpm / min for 10 min in a high-speed centrifuge. The supernatant was discarded, and the remaining solid was washed with ethanol. This step was repeated twice. The sample was then centrifuged again at 10,000 rpm / min for 10 min, and the supernatant was discarded. The remaining solid was washed with ultrapure water. This step was repeated twice. The final solid sample was dried in an 80℃ oven for 6 h. The sample was then ground uniformly and calcined in a high-temperature tube furnace with an air atmosphere. The temperature was increased to 1000℃ at a rate of 5℃ / min and calcined for 2 h. The drying air flow rate was 100 mL / min. After cooling to room temperature, the sample was removed and ground again to obtain a high-entropy spinel. The catalyst sample was named HEO1.

[0079] Comparative Example 1

[0080] The catalyst in Comparative Example 1 is a common supported catalyst, Fe / Al2O3, which includes Al2O3 support and Fe active component. The mass of Fe active component accounts for 10% of the total mass of the catalyst.

[0081] The preparation method of the catalyst in Comparative Example 1 includes the following steps: 0.72g of... Dissolve in 30 ml of anhydrous ethanol, stirring constantly until completely dissolved, then add 0.9 g of nanoparticles. Add the solution to the iron salt solution and stir until homogeneous. Stir the mixture with a magnetic stirrer at 50°C until it becomes a paste. Then, dry the paste in an oven at 105°C for 12 hours. Grind the resulting dried solid into small particles between 0.08 and 0.16 mm, and then calcine it in a muffle furnace at a heating rate of 20°C / min to a final temperature of 800°C for 2 hours. After cooling to room temperature, grind again to obtain a 10% iron loading. Catalyst sample CS1.

[0082] Comparative Example 2

[0083] The catalyst in Comparative Example 2 is a common supported catalyst. Including carriers The catalyst contains active component Ni, which accounts for 10% of the total catalyst mass.

[0084] The preparation method of the catalyst in Comparative Example 2 includes the following steps: 0.31g of... Dissolve in 40 ml of anhydrous ethanol, stirring constantly until completely dissolved, then add 1 g of nanoparticles. Add to the iron salt solution and stir until homogeneous. The remaining steps are the same as the catalyst preparation method in Example 1, yielding a catalyst with a nickel loading of 10%. Catalyst sample CS2.

[0085] Comparative Example 3

[0086] The catalyst in Comparative Example 3 was a spinel-structured catalyst. It includes a trivalent iron at a B site and a divalent metal at an A site. The amount of Fe accounts for 2 / 7 of the total amount of all elements in the catalyst, and the amount of Mg accounts for 1 / 7 of the total amount of all elements in the catalyst.

[0087] The preparation method of the catalyst in Comparative Example 3 includes the following steps: 0.1 mol of... and 0.05 mol Each catalyst was added to 50 mL of ultrapure water, and the remaining steps were the same as the catalyst preparation method in Example 1, to obtain a conventional spinel-structured catalyst. Sample TC1.

[0088] Comparative Example 4

[0089] The catalyst in Comparative Example 4 is a medium-entropy spinel configuration catalyst. It includes a trivalent iron at a B site and a divalent metal at an A site. The amount of Fe accounts for 2 / 7 of the total amount of all elements in the catalyst, while the amounts of Mg and Co each account for 1 / 14 of the total amount of all elements in the catalyst.

[0090] The preparation method of the catalyst in Comparative Example 4 includes the following steps: 0.1 mol of... 0.025 mol and 0.025 mol Each catalyst was added to 50 mL of ultrapure water, and the remaining steps were the same as the catalyst preparation method in Example 1, to obtain a medium-entropy spinel-structured catalyst (Co). 0.5 Mg 0.5 Fe2O4 sample TC2.

[0091] Product effectiveness test

[0092] 1. Results of SEM, XRD, Raman and TEM-EDS

[0093] Figure 2 SEM images of catalyst HEO1, by Figure 2 It can be seen that the catalyst HEO1 has an irregular short rod-like structure with a length between 5 and 20 μm, and also contains some irregular fine particles with a particle size between 10 and 100 nm. In addition, some void structures can be clearly observed on the surface of the rod-like structure.

[0094] Figure 3 The XRD pattern of catalyst HEO1 is shown below. Figure 3 It can be seen that the prepared The high-entropy catalyst exhibits typical spinel crystal form diffraction peaks, and all spinel diffraction peaks can be compared with... , , , and The diffraction peaks overlapped. Furthermore, the sharp XRD peaks indicated that the prepared HEOs sample had high crystallinity, and the absence of prominent impurity diffraction peaks suggested the formation of an impurity-free sample. Spinel phase.

[0095] Figure 4 The Raman spectrum of catalyst HEO1 is shown below. Figure 4 It can be seen that the prepared The high-entropy catalyst exhibited three peaks in the Raman spectrum, located at... , and . The peaks corresponding to the nearby wavenumbers represent tetrahedral lattices, 500-600 cm⁻¹. −1 The wavenumbers between these peaks represent the ferrite octahedral lattice. These peaks are typical Raman spectral peaks for the spinel configuration, further demonstrating the formation of a high-entropy structure. Spinel phase.

[0096] Figure 5The TEM-EDS mapping spectrum of catalyst HEO1 is shown below. Figure 5 It can be seen that the prepared Energy dispersive spectroscopy (EDS) line scans of the high-entropy catalyst clearly show the presence of elements Fe, Co, Ni, Cu, Zn, Mg, and O, which are randomly and uniformly distributed. This is one of the necessary conditions for the formation of high-entropy oxides.

[0097] 2. Catalytic effect test

[0098] Reactant and catalyst filling: Take 1g of waste polypropylene-kitchen waste oil mixture (waste polypropylene:kitchen waste oil = 3:7) and fill it into the middle of the first quartz tube (to fix the gasification reaction sample); take 0.5g of the catalyst prepared in each of the above examples and comparative examples and fill it into the middle of the second quartz tube (to fix the catalyst sample); place the quartz tube in the fixed bed reactor, connect the gas pipeline, and introduce N2 with a flow rate of 100mL / min.

[0099] Co-gasification and catalytic reforming: First, the second-stage reactor is heated to 750°C at a heating rate of 15°C / min; then, the first-stage reactor is heated to 150°C at a heating rate of 15°C / min, and then ultrapure water is introduced at a flow rate of 0.1 mL / min. After that, the outlet gas is collected. Then, after the first-stage reactor is heated to 550°C, the gas collection is stopped after the reactants are fully vaporized.

[0100] Table 1. Yields of reaction products using catalysts from the examples and comparative examples (yield units: mmol / g)

[0101]

[0102] As shown in Table 1, compared to supported catalysts... and Spinel-structured catalysts and medium-entropy spinel catalyst The high-entropy spinel ferrite catalyst HEO1 of this invention has a better catalytic effect on the volatiles of the co-gasification of waste polypropylene-kitchen waste oil mixture, and at the same time, it also improves the catalytic effect on the main product, syngas. The increase in CO production is significant, especially in H2, meeting the requirements for producing hydrogen-rich syngas. Meanwhile, the gas production trends of TC1 and TC2 are basically consistent with HEO1, but their yields are lower, with the medium-entropy TC2 having a higher gas production capacity than TC1. Furthermore, the high-entropy spinel ferrite catalyst HEO1 has a better effect on reducing... and In terms of production output, it performed worse than the supported catalysts CS1 and CS2.

[0103] Furthermore, it is worth noting that if three or four elements, Fe, Ni, Co, and Mg, are used to prepare, for example... According to the definition of high entropy and actual experimental results, this type of spinel oxide catalyst does not possess a high entropy effect, meaning it cannot exhibit the superior catalytic performance brought about by the high entropy effect. Its performance is also far inferior to the high entropy catalyst with five metals forming the A-site proposed in this invention. Or a high-entropy catalyst formed by six metals at site A. .

[0104] 3. Evaluation of catalytic stability

[0105] Catalyst filling and catalytic reforming experiment: Take 0.5g of the catalyst prepared in each of the above examples and comparative examples, fill it into the middle of the second section of the quartz tube (fix the catalyst sample), place the quartz tube in the fixed bed reactor, connect the gas pipeline, and introduce N2 with a flow rate of 100mL / min. First, heat the second section of the reactor to 750℃ at a heating rate of 15℃ / min.

[0106] Co-gasification and reactant feeding: After heating the first-stage reactor to 150°C at a heating rate of 15°C / min, ultrapure water with a flow rate of 0.1 mL / min is introduced. Then, the outlet gas is collected. After the first-stage reactor is heated to 550°C, the waste polypropylene-kitchen waste oil mixture (waste polypropylene:kitchen waste oil = 3:7) is introduced into the middle of the first-stage quartz tube at a flow rate of 0.05 mL / min using an injection pump for gasification. After the mixture reaches the reactor and begins to gasify, the timing is started.

[0107] Table 2. Stability evaluation of catalyst HEO1 (yield unit: mmol / g) cat .s)

[0108]

[0109] As shown in Table 2, the high-entropy spinel-type ferrite catalyst HEO1 prepared in Example 1 of this invention... The yield increases rapidly within 2 to 5 minutes, reaching its peak H2 yield at 100 minutes. H2 yield was between 100 min and 500 min. The range fluctuates, but it remains relatively high at 500 minutes. Yield This indicates that the prepared catalyst has a long stability time and good catalytic performance.

[0110] Based on the above results, it can be concluded that the product obtained by this invention... High-entropy spinel-structured catalysts (where A is any five of Co, Ni, Cu, Zn, Mg, and Ca) exhibit excellent conversion performance for pyrolysis / gasification volatiles of complex components and good selectivity for hydrogen. They also demonstrate superior resistance to poisoning, sintering, carbon deposition, high temperature, high activity, and long lifespan. Furthermore, they exhibit long and stable catalytic hydrogen production time and show promising application prospects.

[0111] This concludes the description of the various embodiments of the present invention. Based on the above description, those skilled in the art should have a clear understanding of the present invention.

[0112] It should be noted that, unless explicitly stated otherwise, the numerical parameters in the specification and claims of this invention may be approximate values ​​and can be changed according to the content of this invention. Specifically, all figures in the specification and claims indicating the content of composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases, which means that they include a specific quantity varying by ±10% in some embodiments.

[0113] The ordinal numbers used in the specification and claims, such as "first," "second," "third," "primary," "secondary," as well as Arabic numerals and letters, to modify the corresponding elements (or steps), are intended only to clearly distinguish one element (or step) with a certain name from another element (or step) with the same name, and do not imply that the element (or step) has any ordinal number, nor do they represent the order of one element (or step) with another. Furthermore, unless specifically described or steps must occur in sequence, the order of the above steps is not limited to what is listed above and can be varied or rearranged according to the desired design.

[0114] Those skilled in the art will understand that in the claims and specification of this invention, the word "comprising" does not exclude the presence of elements (or steps) not listed in the claims. The word "a" or "an" preceding an element (or step) does not exclude the presence of a plurality of such elements (or steps).

[0115] For certain implementations, if they are not key aspects of the present invention and are well-known to those skilled in the art, they have not been described in detail in the accompanying drawings or text due to space limitations. In such cases, reference can be made to relevant prior art for understanding. Furthermore, the purpose of providing the above embodiments is merely to ensure that the present invention meets legal requirements. The present invention can be implemented in many different forms and should not be construed as limited to the embodiments described herein. Moreover, the above definitions of elements and methods are not limited to the various specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can make simple modifications or substitutions.

[0116] Similarly, it should be understood that, for the sake of brevity, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of invention should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, the various inventive aspects consist of fewer than all the features of the preceding single embodiment. Furthermore, embodiments may be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0117] The above specific embodiments have provided a detailed description of the purpose, technical means, and beneficial effects of the present invention. It should be understood that the purpose of the detailed description is to enable those skilled in the art to better understand the present invention, and it is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Application of a high-entropy catalyst in the catalytic reforming of oxygen-containing hydrocarbons for hydrogen production; The high-entropy catalyst is The spinel configuration; the B-site is trivalent iron; the A-site is a combination of five or six divalent metallic elements from the following groups: Mg, Co, Ni, Cu, Zn, Ca; the amount of trivalent iron at the B-site accounts for... The total amount of substance of all elements in the A site is 2 / 7 of the total amount of substance of the five or six divalent metallic elements. It is 1 / 7 of the total amount of substance of all elements in it.

2. The application according to claim 1, characterized in that, The raw materials are a mixture of waste polypropylene and waste kitchen oil; the reforming is steam reforming.

3. The application according to claim 2, characterized in that, The application conditions are as follows: the amount of packing material is 0.5-3g or the feed flow rate is 20-100 μL / min, the amount of catalyst is 0.1-1.0 g, the reaction temperature is 700-900 ℃, and the protective gas flow rate is 50-250 mL / min, wherein the protective gas is nitrogen, and it is used for a two-stage gasification-reforming integrated fixed bed.

4. The application according to claim 1, characterized in that, In the high-entropy catalyst The high-entropy catalyst is Spinel configuration; in, The element is a divalent metallic element, selected from any five of the six elements: Mg, Co, Ni, Cu, Zn, and Ca.

5. The application according to claim 4, characterized in that, In the high-entropy catalyst The high-entropy catalyst In the spinel configuration: The position is selected from either Mg or Ca; The position is selected from either Ni or Zn; The position is selected from either Co or Cu; Position and The position is selected from Mg, Co, Ni, Cu, Zn, and Ca, which are different from Two types of elements.

6. The application according to claim 4, characterized in that, In the high-entropy catalyst The The ions are selected from five elements: Co, Ni, Cu, Zn, and Mg, and the amount of each element is the same.

7. An application as described in claim 4, characterized in that, The preparation method of the high-entropy catalyst includes: Step A: Mix the salt solution of trivalent iron and the salt solutions of five divalent metal elements, add an alcohol solvent, mix, and obtain a mixed liquid precursor; Step B involves subjecting the mixed precursor to hydrothermal treatment, centrifugation, washing, drying, and grinding to obtain a solid precursor. Step C involves calcining the solid precursor, cooling it, and then grinding it to obtain the high-entropy catalyst.

8. The application according to claim 7, characterized in that, In the preparation method described above In step A, the salt solution is one or more of nitrate solution, chloride solution, and sulfate solution; the alcohol solvent is one or more of ethanol, ethylene glycol, methanol, propanol, isopropanol, n-butanol, and isobutanol; and the volume of the alcohol solvent is 1.5-2.5 times the volume of water in the salt solution; and / or In step B, the hydrothermal treatment temperature is 180-200 ℃, and the hydrothermal treatment time is 8-24 h; and / or In step C, the calcination is carried out in an air atmosphere at a temperature of 850-1050 ℃ for 2-8 h and an air flow rate of 50-200 mL / min.

9. The application according to claim 8, characterized in that, In the preparation method described above In step A, the mixing involves continuous stirring at 25-45°C, a stirring speed of 300-400 rpm / min, and a stirring time of 15-45 min; the precursor for the mixture is a transparent precursor; and / or In step B, the centrifugation is performed in a high-speed centrifuge, with 6-10 centrifugations, a centrifugation rate of 9000-12000 rpm, and a centrifugation time of 8-15 minutes; and / or In step B, the washing is performed 6-10 times, including 3-5 washes with anhydrous ethanol followed by 3-5 washes with ultrapure water; and / or In step B, the drying is carried out in an oven at a temperature between 80-100°C; and / or In step C, the calcination is carried out in a tube furnace; and / or In steps B and C, the grinding is carried out in an agate mortar.

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