Method for preparing high-entropy oxide carbon capture catalyst and catalyzing and desorbing CO2

Abstract

The invention discloses a method for preparing a high-entropy oxide carbon capture catalyst and catalyzing and desorbing CO2. The method comprises the following steps: weighing 45 to 50 mmol of Al (NO) 3.9 H2O and 85 to 90 mmol of citric acid; respectively dissolving different metal compounds in 950-1050 mL of H2O to prepare a solution, and stirring for 8-12 minutes; the molar ratio of different metal compounds is (0.5-1): (0.5-1); the obtained solution is stirred at the temperature of 65-70 DEG C until the viscous syrup-shaped consistency is achieved; transferring into a preheating oven at 190-220 DEG C for 1-2 hours to decompose the citric acid precursor, and grinding for 5-10 minutes to obtain powder; transferring the powder into a 950-1050 mL corundum crucible, and putting the corundum crucible into a muffle furnace for calcining; the temperature is set to be 750-800 DEG C, the heating rate is 2-3 DEG C / min, and the process lasts for 6-8 hours to obtain the catalyst; the method is simple in preparation process, high in safety, low in preparation raw material price and wide in application range, meanwhile, the high-entropy oxide material reduces CO2 absorption and desorption cyclic regeneration energy consumption, and the method has a good development prospect in the field of carbon capture materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon neutralization, and particularly relates to a method for preparing a high-entropy oxide carbon capture catalyst and catalytic desorption of CO2. Background Art

[0002] Since the Industrial Revolution, the demand for fossil fuels (such as coal, oil, and natural gas) by humans has increased sharply. These fossil fuels are widely used in industrial production, transportation, electricity, and other fields, and are the main sources of carbon dioxide emissions. For example, between 1850 and 1960, global emissions continued to rise mainly due to industrialization and population growth, and industrialized countries dominated the emissions at that time. In 2024, the total carbon dioxide emissions related to energy reached a record high of 7.8 billion tons.

[0003] High-entropy spinel oxides are porous functional materials formed by the self-assembly of oxygen ion coordination bonds with multiple metal cations (usually ≥5 kinds) randomly distributed in the spinel (AB2O4) crystal structure in near equimolar ratios. The combination of its unique multi-component high-entropy characteristics and regular spinel lattice structure endows the material with an adjustable pore structure, high specific surface area, and abundant surface active sites, showing great application potential in the fields of catalysis, catalytic separation, energy storage, etc.

[0004] As an emerging branch of the spinel material family, high-entropy spinel oxides inherit the stability and flexibility of the spinel structure. In a typical high-entropy spinel system, the A-site and B-site can be jointly occupied by transition metals (such as manganese Mn, iron Fe, cobalt Co, nickel Ni, copper Cu, etc.) and some rare earth or main group metal ions to form a highly disordered but orderly arranged crystal structure unit, constructing a new material system that combines the advantages of the spinel structure and the high-entropy effect.

[0005] Compared with traditional single or binary spinel oxides, high-entropy spinel oxides exhibit better thermal stability, chemical stability, and unique electron and ion transport characteristics due to the lattice distortion, sluggish diffusion, and synergistic interaction brought by the "high-entropy effect". Among them, some high-entropy spinel systems have become research hotspots, and the synthesis processes of some materials have gradually matured and begun to move towards industrial application. As an innovative branch of spinel materials, high-entropy spinel oxides integrate the structural stability of traditional spinels and the multi-element synergistic advantages of high-entropy materials, effectively overcoming the limitations of traditional spinels in terms of single function and environmental adaptability.

[0006] High-entropy spinel oxides have demonstrated remarkable performance in catalysis. Catalysis, a technique that exploits the surface properties of materials to enrich and separate molecules or ions, is highly sought after for its ease of use, environmental friendliness, and high efficiency. The unique porous structure and abundant surface active sites of high-entropy spinel oxides provide them with enhanced catalytic affinity and selectivity. Breakthroughs have been achieved in recent years, particularly in the removal of heavy metal ions and the catalytic degradation of organic pollutants.

[0007] High-entropy spinel oxides stand out among numerous functional materials due to their outstanding structural stability and excellent multifunctional properties. Their synthesis methods are also developing in the direction of greenness, simplicity, and scalability. High-entropy spinel-based composites not only inherit the advantageous properties of the parent material but also can produce synergistic effects with other functional materials, greatly broadening their application boundaries. Therefore, high-entropy spinel oxides and their derivative materials have broad development prospects in cutting-edge fields such as environmental governance, energy storage and conversion, catalytic engineering, sensor technology, and biomedicine. Summary of the Invention

[0008] The problem to be solved by the present invention is the research and development of a high entropy oxide catalyst and a method for catalytic desorption of CO2.

[0009] The present invention discloses a method for preparing a high entropy oxide carbon capture catalyst and catalytically desorbing CO2, comprising the following steps: The present invention utilizes sol-gel method to prepare high entropy oxide (1) Weigh 45-50 mmol Al(NO)3·9H2O and 85-90 mmol citric acid; (2) dissolving each metal compound in 950-1050 mL of H2O to prepare a solution and stirring for 8-12 minutes; (3) stirring the resulting solution at a temperature of 65-70° C. until it reaches a viscous syrupy consistency; (4) transferring the mixture to a preheated oven at 190-220°C for 1-2 hours to decompose the citric acid precursor, and grinding the mixture into a powder for 5-10 minutes; (5) The powder was transferred to a 950-1050 mL corundum crucible and placed in a muffle furnace for calcination. The temperature was set at 750-800 °C, the heating rate was 2-3 °C / min, and the process lasted for 6-8 hours to obtain the catalyst. (6) After the prepared drugs are placed in ampoules, they are numbered according to the drug mass required for different measurements and a regular control group is designed for characterization and performance measurement.

[0010] Beneficial effect: Compared with the reported method for preparing solid amine catalyst (1) The prepared spinel high-entropy oxide catalyst has a particle size of about 400 - 500 nm, with relatively uniform particles and obvious pores, which is beneficial to the absorption of carbon dioxide. The surface area of the absorbent is 14 - 15.6742 m 2 / g, the pore volume is 0.02 - 0.0232 cm 3 / g, and the pore diameter (d) is 5.8 - 6.7 nm. The material is mainly microporous and shows a typical type-IV isotherm; (2) The prepared spinel high-entropy oxide catalyst greatly improves the catalytic desorption energy efficiency of carbon dioxide. From the experimental data, it can be found that the multi-metal sites in the spinel high-entropy oxide provide rich active centers; (3) The high-entropy effect endows the spinel high-entropy oxide with good structural stability. In multiple carbon dioxide catalytic desorption cycle experiments, the spinel high-entropy oxide can maintain the integrity of its crystal structure. The relevant X-ray diffraction (XRD) data shows that after multiple cycles, the spinel phase still exists, without obvious phase transformation or structural collapse. This structural stability ensures its catalytic activity during long-term use. Brief Description of the Drawings

[0011] Figure 1 It is the X-ray diffraction pattern of the catalytic material of the present invention; Figure 2 It is the NH3-TPD pattern of the performance of the catalytic material of the present invention; Figure 3 It is the morphology pattern of the catalytic material of the present invention; the magnification is 5000 times; Figure 4 It is the schematic diagram of the laboratory system device for the performance evaluation of the catalytic material of the present invention; Figure 5 It is the CO2 absorption performance data graph of the catalytic material of the present invention; Figure 6 It is the nitrogen adsorption and desorption curve graph of the catalytic material of the present invention. Detailed Embodiments

[0012] To make the technical solutions of the present invention clear, the technical solutions in the present invention will be described in detail and completely below.

[0013] Example 1: A spinel catalyst with the chemical formula (Ni 0.2 Mn 0.2 Cu 0.2 Zn 0.2 Co 0.2 )Al2O4 , denoted as HE-Al2O4, and the preparation method is as follows: (1) Weigh 40 - 50 mmol of Al(NO)3·9H2O and 85 - 90 mmol of citric acid; (2) Dissolve 4 - 6 mmol of Ni(CH3COO) 2· 4H2O, Mn(NO3)2·6H2O, Cu(NO3)2·3H2O, (CH3COO)2Zn and Co(NO3)2·6H2O in 950 - 1050 mL of H2O; (3) Stir the resulting solution at a temperature of 65 - 70 °C until it reaches a viscous syrup - like consistency; (4) Subsequently, transfer it to a pre - heated oven set at 190 - 220 °C for 1 - 2 hours to decompose the citric acid precursor, and then grind it in a mortar for 5 - 10 minutes into a powder form; (5) Finally, transfer the powder to a 950 - 1050 mL corundum crucible and place it in a muffle furnace for calcination. The temperature is set at 750 - 800 °C, the heating rate is 2 - 3 °C / min, and this process lasts for 6 - 8 hours to obtain the catalyst; (6) After putting the prepared medicine into an ampoule bottle, according to the mass of the medicine required for different determinations, number the medicine and design a regular control group, and then conduct characterization and performance determination.

[0014] Example 2: A spinel catalyst with the chemical formula (Ni 0.2 Mn 0.2 Cu 0.2 Ga 0.2 Co 0.2 )Al2O4. The preparation method is the same as that in Example 1, except that the nitrate of zinc in the mixed metal salts is replaced with a nitrate containing gallium, and the molar ratio is 0.5 - 1:0.5 - 1.

[0015] Example 3: A spinel catalyst with the chemical formula (Ni 0.2 Mn 0.2 Cu 0.2 V 0.2 Co 0.2 )Al2O4. The preparation method is the same as that in Example 1, except that the nitrate of zinc in the mixed metal salts is replaced with an oxide containing vanadium, and the molar ratio is 0.5 - 1:0.5 - 1.

[0016] Example 4: A spinel catalyst with the chemical formula (Ni 0.2 Mn 0.2 Cu 0.2 Sr 0.2 Co 0.2)Al2O4, the preparation method is the same as that of Example 1, except that the mixed metal salt containing zinc nitrate is replaced with an acetate containing strontium, and the molar ratio is 0.5-1:0.5-1.

[0017] Result Detection (1) Scanning Electron Microscope (SEM) A scanning electron microscope (SEM) scans a sample with a focused high-energy electron beam, collects, magnifies, and images different physical information on the sample surface. It is an electron microscope technique for characterizing the microscopic morphology of the sample surface; The instrument model used for this operation is the German ZEISS GeminiSEM300, and the energy spectrometer model is OXFORD XPLore30. A small amount of the sample is directly pasted on the conductive adhesive, and gold sputtering is performed using a Quorum SC7620 sputter coater for 45-50 s at 10-15 mA. Then, the morphology of the sample is photographed and energy spectrum mapping tests are performed using a Zeiss GeminiSEM300 scanning electron microscope. The acceleration voltage for morphology photography is 2-3 kV, and the acceleration voltage for energy spectrum mapping photography is 15-16 kV. The detector is an SE2 secondary electron detector; The spinel catalysts of Examples 1-4 were subjected to SEM detection. The detection results are shown in the figure. The SEM images show that all spinel phases have a consistent particle morphology and uniform particle size; (2) BET Specific Surface Area Measurement Method (BET) A BET physical analyzer measures the surface area and pore structure of a material by utilizing the catalytic properties of the solid material, and can test data such as the adsorption / desorption curve, pore size distribution, total pore volume, and surface area of the material; The BET specific surface area and pore structure of the catalytic material were characterized using a Quantachrome AUTOSORB IQ instrument for automatic specific surface area, micropore size, and chemical action catalytic analyzer. N2 was used as the catalytic gas, and He served as the carrier gas. The material was first degassed at 179-185 °C for 6-7 h, and then N2 was catalyzed at -179- -185 °C. Subsequently, the pore volume, pore size, and specific surface area of a series of materials were calculated; (3) Temperature Programmed Desorption of Ammonia (TPD) As can be seen from the figure, the ammonia desorption temperature and desorption amount of different elements in the high-entropy oxide are different. This reflects the differences in the catalytic intensity and catalytic sites of different elements in the high-entropy oxide for ammonia; For example, a high-entropy oxide containing Ga and V has a large amount of ammonia desorption at a relatively low temperature (200 - 300 °C), while a high-entropy oxide containing Zn and Sr has more ammonia desorption at a slightly higher temperature (300 - 400 °C). This difference is of great significance for studying the application of high-entropy oxides in ammonia capture and conversion. High-entropy oxides may provide a variety of different catalytic sites through their complex elemental composition and structure, thus achieving effective ammonia desorption at different temperatures, which is very helpful for developing efficient ammonia catalytic and conversion materials; (4) X-ray diffraction (XRD) The crystallinity of the spinel catalyst was detected by XRD. The detection results are as described in the figure. The XRD pattern in the figure shows diffraction peaks on the (200), (122), (220), (222), (644), and (400) crystal planes at 2θ values of 31.26°, 36.85°, 44.83°, 55.57°, 59.37°, and 65.14°. These can be identified as belonging to the cubic spinel phase of the space group (JCPDS: PDF#73 - 1959). Other synthesized spinel oxides, including Ni1Al2O4, Cu1Al2O4, and Co1Al2O4, also show similar crystal structures; (5) Evaluation of the catalytic desorption performance of the material using a self-made activity evaluation device Self-made activity evaluation device: The schematic diagram of the activity evaluation system device for the material is as Figure 1 . The system mainly includes three parts: a gas cylinder for simulating exhaust gas, a fixed-bed reactor, and an analyzer for testing; The detector used in the test system is the Schütz S-ANALYZER200 analyzer. The CO2 analysis accuracy of the analyzer is as high as 0.1 - 0.2%. The analyzer is equipped with a touch display control screen, with a reasonable menu structure distribution, an intuitive operation interface, and all status displays, threshold values, and alarm values provided in both analog and digital ways. It can display the detected concentration curve in real time and is suitable for gas concentration detection in various industrial scenarios. The analyzer is equipped with high-precision infrared sensors S-MODULE and SAE-MODULE, uses non-dispersive infrared detection technology, integrates a stable infrared light source, and is configured with a reliable performance photodetector to ensure the detection performance of the analyzer.

[0018] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, not limitations on the implementation manners. Those of ordinary skill in the art can make different forms of changes or variations based on this, and there is no need to enumerate all the implementation manners. At the same time, the general description and specific embodiments in the above text are only used to explain the technical solution of the present invention, not to limit it. Even if the foregoing embodiments are described in detail, those of ordinary skill in the art can still modify the technical solutions of each embodiment or equivalently replace some technical features. As long as these modifications or replacements do not depart from the spirit and scope of the technical solutions of each embodiment of the present invention, they are all included in the protection scope of the claims of the present invention.

Claims

1. A spinel catalyst, characterized in that, Its chemical formula is: (Ni 0.2 Mn 0.2 Cu 0.2 M 0.2 Co 0.2 )Al2O4, where M is a doped metal and is any one of Zn, V, Ga, and Sr.

2. The spinel catalyst according to claim 1, wherein The type of the spinel metal is greater than or equal to 5.

3. A method for preparing a high-entropy oxide carbon capture catalyst and catalytic desorption of CO2, characterized in that, It includes the following steps: The present invention prepares high-entropy oxides by the sol-gel method: (1) Weigh 40-50 mmol of Al(NO)3·9H2O and 85-90 mmol of citric acid; (2) Dissolve 4 - 6 mmol of Ni(CH3COO) 2· 4H2O, Mn(NO3)2·6H2O, Cu(NO3)2·3H2O, (CH3COO)2Zn and Co(NO3)2·6H2O in 950 - 1050 mL of H2O; (3) Stir the obtained solution at a temperature of 65-70 °C until it reaches a viscous syrup-like consistency; (4) Subsequently, transfer it to a preheated oven set at 190-220 for 1-2 hours to decompose the citric acid precursor, and then grind it in a mortar for 5-10 minutes into a powder form; (5) Finally, transfer the powder to a 950-1050 mL corundum crucible and place it in a muffle furnace for calcination. The temperature is set at 750-800 °C, and the heating rate is 2-3 °C / min. This process lasts for 6-8 hours to obtain the catalyst; (6) After putting the prepared medicine into an ampoule bottle, according to the mass of the medicine required for different measurements, number the medicine and design a regular control group, and then conduct characterization and performance measurement; (7) Scanning electron microscope (SEM) The scanning electron microscope (SEM) scans the sample with a focused high-energy electron beam, collects, magnifies and images different physical information on the surface of the sample. It is an electron microscope technology for characterizing the microscopic morphology of the sample surface; The instrument model used for this operation is the German ZEISS GeminiSEM300, and the energy spectrometer model is OXFORD XPLORE30. A small amount of sample is directly pasted on the conductive glue, and sputter coating is carried out for 45-50 s and 10-15 mA using a Quorum SC7620 sputter coater. Then, the morphology of the sample is photographed and energy spectrum mapping is tested with a Zeiss GeminiSEM300 scanning electron microscope. The acceleration voltage for morphology shooting is 2-3 kV, and the acceleration voltage for energy spectrum mapping shooting is 15-16 kV. The detector is an SE2 secondary electron detector; The spinel catalysts of Examples 1-4 were detected by scanning electron microscopy SEM. The detection results are shown in the figure. The scanning SEM images show that all spinel phases have consistent particle morphology and uniform particle size; (8) Specific surface area test method (BET) The BET physical analyzer measures the surface area and pore structure of materials by utilizing the catalytic characteristics of solid materials, and can test data such as the adsorption and desorption curves, pore size distribution, total pore volume and surface area of materials; The BET specific surface area and pore structure of the catalytic material were characterized using a Quantachrome AUTOSORB IQ instrument for automatic specific surface area, micropore size and chemical action catalytic analyzer. N2 was used as the catalytic gas, and He served as the carrier gas. The material was first degassed at 179-185 °C for 6-7 h, and then N2 was catalyzed at -179-185 °C. Subsequently, a series of pore volumes, pore sizes and specific surface areas of the materials were calculated; (9) Temperature-programmed desorption of ammonia (TPD) As can be seen from the figure, the ammonia desorption temperature and desorption amount of different elements in the high-entropy oxide are different, which reflects the differences in the catalytic intensity and catalytic sites of different elements in the high-entropy oxide for ammonia; For example, a large amount of ammonia desorption occurs from high-entropy oxides containing Ga and V at relatively low temperatures (200 - 300 °C), while high-entropy oxides containing Zn and Sr have more ammonia desorption at slightly higher temperatures (300 - 400 °C). This difference is of great significance for studying the application of high-entropy oxides in ammonia capture and conversion. High-entropy oxides may provide multiple different catalytic sites through their complex elemental composition and structure, thereby achieving effective ammonia desorption at different temperatures, which is very helpful for developing efficient ammonia catalytic and conversion materials; (10) X-ray diffraction (XRD) XRD detection was carried out on the crystallinity of the spinel catalyst. The detection results are as shown in the figure. The XRD patterns in the figure show diffraction peaks on the (200), (122), (220), (222), (644), and (400) crystal planes at 2θ values of 31.26°, 36.85°, 44.83°, 55.57°, 59.37°, and 65.14°. These can be identified as belonging to the cubic spinel phase of space group (JCPDS: PDF#73 - 1959). Other synthesized spinel oxides, including Ni1Al2O4, Cu1Al2O4, and Co1Al2O4, also show similar crystal structures; (11) Self-made activity evaluation device to evaluate the catalytic desorption performance of materials Self-made activity evaluation device: The schematic diagram of the activity evaluation system device for materials is shown in Figure 1. The system mainly includes a simulated exhaust gas cylinder, a fixed-bed reactor, and an analyzer test, which are three parts; The detector used in the test system is the Schütz S-ANALYZER200 analyzer. The CO2 analysis accuracy of the analyzer is as high as 0.1 - 0.2%. The analyzer is equipped with a touch display control screen. The menu structure is reasonably distributed, the operation interface is intuitive, all status displays, threshold values, and alarm values are provided in both analog and digital ways, and the detection concentration curve is displayed in real time. It is suitable for gas concentration detection in various industrial occasions. The analyzer is equipped with high-precision infrared sensors S-MODULE and SAE-MODULE, uses non-dispersive infrared detection technology, integrates a stable infrared light source, and is configured with a photodetector with reliable performance, ensuring the detection performance of the analyzer; The detector used in the test system is the Schütz S-ANALYZER200 analyzer. The CO2 analysis accuracy of the analyzer is as high as 0.1 - 0.2%. The analyzer is equipped with a touch display control screen. The menu structure is reasonably distributed, the operation interface is intuitive, all status displays, threshold values, and alarm values are provided in both analog and digital ways, and the detection concentration curve is displayed in real time. It is suitable for gas concentration detection in various industrial occasions. The analyzer is equipped with high-precision infrared sensors S-MODULE and SAE-MODULE, uses non-dispersive infrared detection technology, integrates a stable infrared light source, and is configured with a photodetector with reliable performance, ensuring the detection performance of the analyzer.

4. The SEM instrument model described in step (7) of claim 3 is ZEISS Gemini 300, the energy spectrometer model is OXFORD XPLORE30, a sputtering coater Quorum SC7620 is used for gold sputtering for 45 - 50 s at 10 - 15 mA, the sputtering target material is gold-palladium alloy, the acceleration voltage for morphology shooting is 2 - 3 kV, the acceleration voltage for energy spectrum mapping shooting is 15 - 16 kV, and the detector is an SE2 secondary electron detector.

5. The BET specific surface area and pore structure of the catalytic material are characterized using a Quantachrome AUTOSORB IQ instrument, an automatic specific surface area, micropore and chemical adsorption analyzer, as described in step (8) of claim 3. N2 is used as the adsorption gas, and He acts as the carrier gas. The catalytic material is first degassed at 179 - 185 °C for 6 - 7 h and then adsorbs N2 at - 179 - 185 °C.

6. The self-made material activity evaluation device is adopted as described in step (11) of claim 3. The system mainly includes three parts: a gas cylinder for simulated exhaust gas, a fixed-bed reactor, and an analyzer for testing.

7. The detector used in the test system described in step (11) of claim 3 is a Schütz S-ANALYZER200 analyzer. The CO2 analysis accuracy of the analyzer is as high as 0.1 - 0.2%, equipped with a high-precision infrared sensor S-MODULE and SAE-MODULE, using non-dispersive infrared detection technology, integrating a stable infrared light source, and configuring a reliable performance photodetector.

8. Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, not limitations on the implementation manners. Those of ordinary skill in the art can make different forms of changes or variations based on this, and there is no need to enumerate all implementation manners. At the same time, the general description and specific embodiments above are only used to explain the technical solution of the present invention, not to limit it. Even if the above embodiments are described in detail, those of ordinary skill in the art can still modify the technical solutions of each embodiment or equivalently replace some technical features. As long as these modifications or replacements do not depart from the spirit and scope of the technical solutions of each embodiment of the present invention, they are all included in the protection scope of the claims of the present invention.

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