Metal monatomic supported aluminum oxide ceramic dot matrix catalyst as well as preparation method and application thereof

Abstract

The invention relates to a metal monatomic supported aluminum oxide ceramic dot matrix catalyst as well as a preparation method and application thereof. The metal monatomic supported aluminum oxide ceramic dot matrix catalyst comprises an aluminum oxide ceramic dot matrix catalyst framework, wherein the aluminum oxide ceramic dot matrix catalyst framework has a three-period extremely small curved surface structure; the metal single atoms are loaded on the aluminum oxide ceramic dot matrix catalyst framework. The metal monatomic supported aluminum oxide ceramic dot matrix catalyst has high specific surface area, rich surface active sites and high catalytic activity and stability, and can be efficiently and circularly used for ozone catalytic oxidation water treatment. The invention also provides a general preparation method of the metal monatomic supported aluminum oxide ceramic dot matrix catalyst.

Description

Technical Field

[0001] The present invention belongs to the fields of catalytic materials and water treatment, and particularly relates to a metal single-atom loaded alumina ceramic lattice catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Wastewater discharged from industries such as chemical engineering, textile, and printing and dyeing is mostly high-concentration and difficult-to-degrade organic wastewater. To promote the recycling and green transformation of wastewater, the deep purification of wastewater has become an inevitable requirement and a key link for the up-to-standard discharge and resource utilization of industrial wastewater.

[0003] Oxide ceramics such as alumina and silica are commonly used catalyst carriers, which have advantages such as high mechanical strength, stable chemical properties, and long service life. After further loading non-metallic or metal components on their surfaces, they are widely used in the preparation of environmental catalysts. However, the industrial preparation of traditional ceramics has problems such as high energy consumption, low material utilization rate, and limited design space, and it is difficult to have both excellent mechanical properties and multifunctionality. For traditional alumina-based catalysts loaded with metals, the particles inside are usually isolated and discontinuous, which results in a large amount of "dead volume" inside the catalyst, low internal surface area utilization rate, and great material waste. In addition, the active components of traditional metal-loaded catalysts are unevenly distributed, the utilization rate of metal atoms is low, and the overall catalytic activity needs to be improved. Therefore, there is an urgent need to develop a catalyst with both multi-reaction sites and a hierarchical pore structure, which has more active reaction sites and better reaction residence time while ensuring the structural stability of the catalyst, and improves the catalytic activity of the catalyst.

[0004] 3D printing ("additive manufacturing") is a manufacturing technology that converts a digital model into a physical part by layer-by-layer accumulation of materials. It has significant advantages over "equivalent material manufacturing" and "subtractive manufacturing" technologies in the field of preparing complex-structured parts. Currently, 3D printing technology has been widely applied to fields such as aerospace, automotive, shipbuilding, national defense and military industry, energy and power, rail transit, petrochemical industry, medical and health, electronics, molds, cultural and creative industries, architecture, and cultural and creative fields. The triply periodic minimal surface structure (TPMS structure) is a minimal surface structure with periodic repeating units in three-dimensional space. The surface lattice structure represented by the TPMS structure has excellent mechanical properties, and at the same time has the characteristics of periodicity and zero average curvature everywhere.

[0005] There are also examples in the prior art of preparing high-performance ceramic materials using 3D printing technology and TPMS structures. For example, Patent Document 1 discloses a Ni-loaded TPMS-structured Al2O3-based monolithic catalyst and its preparation method. This catalyst has high mass and heat transfer efficiency, easy sample recovery, and good reusability, and can be used for CO methanation. However, the active component Ni loaded by the general impregnation method often exists in the form of nanoclusters, with low utilization rate of metal atoms, and the overall reaction activity still needs to be improved. Moreover, the mechanical compressive properties of the material are not fully improved during its preparation process, and it will be restricted to a certain extent during use.

[0006] Cited Literature

[0007] Patent Document 1: CN118925731A Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] In view of the problems of low internal surface area utilization rate of traditional alumina-based catalysts, easy agglomeration of loaded metal catalysts, uneven catalytic active sites, and most existing single-atom catalysts being in powder form and difficult to reuse, there is a need to provide an alumina-based catalyst with a high specific surface area, rich and evenly distributed catalytic active sites, high stability, and recyclability.

[0010] Solutions for Solving the Problems

[0011] To solve the above problems, in the present invention, 3D printing technology and triply periodic minimal surface structures are used to precisely control the micron-scale pore structure inside alumina ceramics, construct a three-dimensional hierarchical porous interconnected structural functional unit, and load an efficient metal single-atom catalyst on this basis, thereby preparing a metal single-atom-loaded alumina ceramic lattice catalyst with high mass transfer and catalytic efficiency, good stability, and high recyclability.

[0012] The present invention provides a metal single-atom-loaded alumina ceramic lattice catalyst, which comprises:

[0013] An alumina ceramic lattice catalyst skeleton having a triply periodic minimal surface structure; and metal single atoms loaded on the alumina ceramic lattice catalyst skeleton.

[0014] According to the above-mentioned catalyst, the metal single atoms are selected from one or more of manganese, iron, nickel, and cobalt;

[0015] wherein, the loading amount of the metal single atoms is 0.05 - 3.0 wt%.

[0016] According to the catalyst described above, the triply periodic minimal surface structure is a Gyroid lattice structure, an IWP lattice structure, or a Neovius lattice structure.

[0017] According to the catalyst described above, the side length of the relative density structure of the triply periodic minimal surface structure is (2 - 20) mm × (2 - 20) mm × (2 - 20) mm; the array period of the lattice unit cell of the triply periodic minimal surface structure is (1 - 20) × (1 - 20) × (1 - 20); the relative density of the triply periodic minimal surface structure is 20% - 80%.

[0018] According to the catalyst described above, wherein,

[0019] the porosity of the alumina ceramic lattice catalyst skeleton is 20% - 80%;

[0020] the specific surface area of the alumina ceramic lattice catalyst skeleton is 10 m 2 / g - 200 m 2 / g;

[0021] the compressive strength of the alumina ceramic lattice catalyst skeleton is 5 MPa - 300 MPa.

[0022] The present invention also provides a preparation method of the metal single - atom - loaded alumina ceramic lattice catalyst according to the above, which includes the following steps:

[0023] (1) Obtain a precursor of the alumina ceramic lattice catalyst skeleton by 3D printing through surface - projection micro - stereolithography technology;

[0024] (2) Debind and sinter the precursor of the alumina ceramic lattice catalyst skeleton to obtain the alumina ceramic lattice catalyst skeleton;

[0025] (3) Prepare an impregnation solution containing a metal salt, a zinc salt, and 2 - methylimidazole for forming metal single atoms, put the alumina ceramic lattice catalyst skeleton into the impregnation solution, perform ultrasonic impregnation, static standing, and filtration to obtain a precursor of the metal single - atom - loaded alumina ceramic lattice catalyst;

[0026] (4) Subject the precursor of the metal single - atom - loaded alumina ceramic lattice catalyst to a post - treatment process to obtain the metal single - atom - loaded alumina ceramic lattice catalyst.

[0027] According to the preparation method described above, in step (1),

[0028] Determine a three-dimensional geometric configuration file with a triply periodic minimal surface structure in 3D design software; pour alumina slurry into the liquid tank of a 3D printer, import the three-dimensional geometric configuration file into the computer connected to the 3D printer for slicing, and then cure layer by layer under ultraviolet light for 3D printing;

[0029] Among them, the layer thickness of the slicing is 5 - 50 μm; the exposure time for each layer is 1 - 10 seconds;

[0030] The wavelength of the ultraviolet light is 300 to 450 nm; the light intensity of the ultraviolet light is 2 - 100 mW / cm 2 。

[0031] According to the preparation method described above, in step (2), the debinding and sintering include the following three stages:

[0032] Stage 1: Debind, heat-insulate, and cool the alumina ceramic lattice catalyst skeleton precursor to room temperature to obtain the alumina ceramic lattice catalyst skeleton precursor-I;

[0033] Among them, stage 1 is carried out in a vacuum environment, the heating rate of debinding is 0.5 - 5 °C / min; the temperature of debinding is 400 - 800 °C; the heat-insulating time is 160 - 220 min;

[0034] Stage 2: Debind, heat-insulate, and cool the alumina ceramic lattice catalyst skeleton precursor-I to room temperature to obtain the alumina ceramic lattice catalyst skeleton precursor-II;

[0035] Among them, stage 2 is carried out in an air environment, the heating rate of debinding is 0.5 - 5 °C / min, the temperature of debinding is 800 - 1200 °C, and the heat-insulating time is 20 - 80 min;

[0036] Stage 3: Sinter, heat-insulate, and cool the alumina ceramic lattice catalyst skeleton precursor-II to room temperature to obtain the alumina ceramic lattice catalyst skeleton;

[0037] Among them, stage 3 is carried out in an air environment, the heating rate of sintering is 2 - 8 °C / min, the temperature of sintering is 1400 - 1800 °C, and the heat-insulating time is 40 - 120 min.

[0038] According to the preparation method described above, in step (3), the molar ratio of the metal salt, zinc salt, and 2-methylimidazole is (0.1 - 10 mmol):(1 - 20 mmol):(10 - 120 mmol);

[0039] Among them, the metal salt is one or more of acetylacetonate, acetate, ferrocene salt, or citrate of manganese, iron, nickel, or cobalt;

[0040] The zinc salt is selected from one or more of zinc acetate, zinc nitrate, zinc chloride, zinc sulfate and zinc carbonate;

[0041] The time for ultrasonic impregnation is 10 - 120 min; the time for standing is 12 - 96 hours.

[0042] According to the preparation method described above, in step (4), the post-treatment process includes drying, anaerobic calcination, heat preservation, and cooling to room temperature;

[0043] Among them,

[0044] The temperature for drying is 40 - 80 °C; the time for drying is 10 - 60 min;

[0045] The heating rate for calcination is 1 - 5 °C / min; the temperature for calcination is 800 - 1200 °C; the time for heat preservation is 1 - 5 hours.

[0046] The present invention further provides the application of the metal single-atom loaded alumina ceramic lattice catalyst or the metal single-atom loaded alumina ceramic lattice catalyst obtained by the preparation method described above in sewage treatment, preferably in the application of ozone catalytic oxidation water treatment.

[0047] Effects of the Invention

[0048] 1. The three-period minimal surface lattice structure constructed by the present invention has the characteristics of high specific surface area, periodicity, internal penetration and zero mean curvature everywhere, overcoming the weaknesses of a large amount of "dead volume" inside the current catalyst and low utilization rate of the internal surface area.

[0049] 2. The metal single-atom catalyst loaded in the present invention can maximize the utilization rate of metals, overcome the problem of metal agglomeration in traditional catalysts, and the obtained metal single-atom loaded ceramic lattice catalyst has richer surface active sites and a hierarchical pore structure, and can efficiently generate reactive oxygen species (hydroxyl radicals, superoxide anions, etc.), while maintaining the high reaction activity of the catalyst, taking into account the hydrodynamic structure of the internal pores, and realizing the simultaneous improvement of reaction activity and mass transfer efficiency in the sewage treatment process.

[0050] 3. The present invention realizes the 3D printing preparation of the micro-nano alumina ceramic curved surface lattice material, solving the problems of low utilization rate of traditional alumina catalyst materials and limited design space at present.

[0051] 4. The present invention uses methods such as ultrasonic impregnation and anaerobic calcination to successfully load metal single-atom catalysts on the curved surface lattice skeleton of alumina ceramics, breaking through the bottleneck that existing single-atom catalysts are mostly powders and difficult to reuse, and creating a general preparation method for an alumina ceramic lattice catalyst with metal single atoms loaded for efficient recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic flow chart of preparing an alumina ceramic lattice catalyst with metal single atoms loaded in the present invention.

[0053] Figure 2 It is a temperature control curve graph of the degreasing and sintering process of the alumina ceramic lattice catalyst skeleton precursor in Example 1.

[0054] Figure 3 It is a physical diagram of the alumina ceramic lattice catalyst skeleton precursor obtained in Examples 1-3 and Comparative Example 1.

[0055] Figure 4 It is a physical diagram of the alumina ceramic lattice catalyst skeleton after degreasing and sintering in Examples 1-3 and Comparative Example 1.

[0056] Figure 5 It is a physical diagram of the manganese single-atom loaded alumina ceramic lattice catalyst prepared in Examples 1-3 and Comparative Example 1;

[0057] Figure 6 It is a scanning electron microscope image of the manganese single-atom loaded alumina ceramic lattice catalyst in Example 1.

[0058] Figure 7 It is a morphological diagram of the surface active sites of the manganese single-atom loaded alumina ceramic lattice catalyst in Example 1 under a spherical aberration electron microscope.

[0059] Figure 8 It is a uniaxial compression stress-strain curve graph of the alumina ceramic lattice catalyst skeleton prepared at each stage in Examples 1-3 and Comparative Example 1.

[0060] Figure 9 It is a specific surface area and mass transfer performance graph of the square lattice structure and other different three-period minimal surface lattice structures.

[0061] Figure 10 It is an experimental device for ozone catalytic oxidation sewage treatment in Example 1 and Comparative Examples 2-4.

[0062] Figure 11 It is a comparison graph of the degradation curves of the simulated wastewater for ozone catalytic oxidation sewage treatment using the catalysts prepared in Example 1 and Comparative Examples 2-3 and without using a catalyst.

[0063] Figure 12 Degradation curve comparison diagram of actual wastewater in ozone catalytic oxidation sewage treatment using the catalysts prepared in Example 1 and Comparative Examples 3-4.

[0064] Figure 13 Three-dimensional fluorescence test comparison diagram of actual wastewater in ozone catalytic oxidation sewage treatment using the catalyst prepared in Example 1.

[0065] Figure 14 Circulation test curve diagram of actual wastewater in ozone catalytic oxidation sewage treatment using the catalyst prepared in Example 1.

[0066] Figure 15 Mechanism simulation diagram of the ozone catalytic oxidation process using the catalyst prepared in Example 1. Detailed implementation manners

[0067] The various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The special term "exemplary" here means "serving as an example, embodiment, or illustration". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0068] In addition, to better illustrate the present invention, numerous specific details are given in the following detailed implementation manners. Those skilled in the art should understand that the present invention can be implemented without some specific details. In other instances, methods, means, equipment, and steps well-known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

[0069] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0070] In this specification, the meaning expressed by using "can" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0071] In this specification, the so-called "some specific / preferred implementation manners", "other specific / preferred implementation manners", "implementation manners", etc. refer to the specific elements (for example, features, structures, properties, and / or characteristics) related to the implementation manner described, which are included in at least one of the implementation manners described here, and may or may not exist in other implementation manners. In addition, it should be understood that the elements can be combined in various implementation manners in any suitable way.

[0072] In this specification, the numerical range expressed by using "numerical value A~numerical value B" refers to the range including the endpoint numerical values A and B.

[0073] "Room temperature" in this specification is 15 - 30°C.

[0074] The present invention provides a metal single - atom - loaded alumina ceramic lattice catalyst, which comprises:

[0075] An alumina ceramic lattice catalyst framework, the alumina ceramic lattice catalyst framework having a three - periodic minimal surface structure; and

[0076] Metal single atoms loaded on the alumina ceramic lattice catalyst framework.

[0077] The present invention also provides a preparation method of the aforesaid metal single - atom - loaded alumina ceramic lattice catalyst, which comprises the following steps:

[0078] (1) Obtaining a precursor of the alumina ceramic lattice catalyst framework by 3D printing through surface - projection micro - stereolithography technology;

[0079] (2) Debinding and sintering the precursor of the alumina ceramic lattice catalyst framework to obtain the alumina ceramic lattice catalyst framework;

[0080] (3) Preparing an impregnation solution containing a metal salt, a zinc salt, and 2 - methylimidazole for forming metal single atoms, putting the alumina ceramic lattice catalyst framework into the impregnation solution, performing ultrasonic impregnation, standing, and filtering to obtain a precursor of the metal single - atom - loaded alumina ceramic lattice catalyst;

[0081] (4) Subjecting the precursor of the metal single - atom - loaded alumina ceramic lattice catalyst to a post - treatment process to obtain the metal single - atom - loaded alumina ceramic lattice catalyst.

[0082] Figure 1 It is a schematic flow chart for preparing a metal single - atom - loaded alumina ceramic lattice catalyst, including steps such as 3D printing a precursor of the alumina ceramic lattice catalyst framework by surface - projection micro - stereolithography technology, debinding and sintering, ultrasonic loading, and anaerobic calcination.

[0083] The following elaborates on each step in detail.

[0084] Step 1)

[0085] In a three-dimensional design software, by numerically solving different level set approximation equations, a surface lattice structure represented by a triply periodic minimal surface structure (TPMS) was designed as the main structure of the alumina ceramic lattice catalyst skeleton, and a three-dimensional geometric configuration file was obtained. Pour the alumina slurry into the liquid tank of the surface projection microstereolithography printer, import the three-dimensional geometric configuration file into the computer connected to the surface projection microstereolithography printer and perform slicing, and use the surface projection microstereolithography technology to cure layer by layer under ultraviolet light for 3D printing. The obtained alumina ceramic model is removed from the sacrificial layer, and the residual slurry inside the structure is removed by ultrasonic cleaning and water flow flushing. After cleaning, it is naturally dried to obtain a precursor of the alumina ceramic lattice catalyst skeleton.

[0086] The alumina ceramic model obtained during the printing process includes a lattice structure model (structural layer) and a sacrificial layer. Among them, the sacrificial layer refers to the part that is removed after printing, and the sacrificial layer plays a role in supporting complex structures and preventing structure collapse during printing.

[0087] In the present invention, the metal single atoms are selected from one or more of manganese, iron, nickel, and cobalt.

[0088] In the present invention, the loading amount of the metal single atoms is 0.05 - 3.0 wt%, and for example, it can be 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2.0 wt%, 2.4 wt%, 2.5 wt%, etc.

[0089] In the present invention, when the metal active component is loaded in the form of single atoms, the utilization rate of metal atoms can be maximized, the masking loss of active sites caused by metal clusters can be avoided, and the reaction activity and efficiency of the catalyst can be greatly improved.

[0090] In some specific embodiments of the present invention, the triply periodic minimal surface structure is a Gyroid lattice structure, an IWP lattice structure, a Neovius lattice structure, etc. In the present invention, the side length of the relative density structure of the triply periodic minimal surface structure is (2 - 20) mm × (2 - 20) mm × (2 - 20) mm, and for example, it can be 3 mm × 3 mm × 3 mm, 4 mm × 4 mm × 4 mm, 5 mm × 5 mm × 5 mm, 6 mm × 6 mm × 6 mm, 7 mm × 7 mm × 7 mm, 8 mm × 8 mm × 8 mm, 10 mm × 10 mm × 10 mm, 12 mm × 12 mm × 12 mm, 15 mm × 15 mm × 15 mm, 18 mm × 18 mm × 18 mm, etc.

[0091] In the present invention, the array period of the lattice unit cell of the triply periodic minimal surface structure is (1 to 20) × (1 to 20) × (1 to 20), and for example, it can be 2×2×2, 3×3×3, 4×4×4, 5×5×5, 8×8×8, 10×10×10, 12×12×12, 15×15×15, 18×18×18, etc.

[0092] In the present invention, the relative density of the triply periodic minimal surface structure is 20 to 80%, and for example, it can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, etc.

[0093] In some specific embodiments of the present invention, the side length of the relative density structure of the triply periodic minimal surface structure is 5 mm × 5 mm × 5 mm, the array period of the lattice unit cell is 2×2×2, and the relative density is 30%.

[0094] In the present invention, the basic properties such as the porosity and specific surface area of the alumina ceramic lattice catalyst skeleton can be controlled by the parameters of the level set approximation equation.

[0095] In the present invention, the porosity of the alumina ceramic lattice catalyst skeleton is 20 - 80%, and for example, it can be 30%, 41%, 55%, 60%, 70%, etc.

[0096] In the present invention, the specific surface area of the alumina ceramic lattice catalyst skeleton is 10 m 2 / g - 200 m 2 / g, and for example, it can be 20 m 2 / g, 50 m 2 / g, 78 m 2 / g, 111.3 m 2 / g, 150 m 2 / g, 158.7 m 2 / g, etc.

[0097] In the present invention, the compressive strength of the alumina ceramic lattice catalyst skeleton is 5 MPa to 300 MPa, and for example, it can be 10.0 MPa, 20.0 MPa, 30.0 MPa, 40.0 MPa, 50.0 MPa, 70.0 MPa, 100.0 MPa, 150.0 MPa, 200.0 MPa, 250.0 MPa, 280.0 MPa, etc.

[0098] In the present invention, the layer thickness of the slice is 5 to 50 μm, and for example, it can be 7 μm, 15 μm, 20 μm, 25 μm, 45 μm, etc.

[0099] In the present invention, the exposure time of the structure layer is 1 to 6 seconds, and for example, it can be 2 seconds, 3 seconds, 4 seconds, 5 seconds, etc.

[0100] In the present invention, the exposure time of the sacrificial layer is 3 to 10 seconds. For example, it can be 4 seconds, 5 seconds, 6 seconds, 6.5 seconds, 7 seconds, 9 seconds, etc.

[0101] In the present invention, setting different exposure times of the sacrificial layer can enhance the adhesion between the sacrificial layer and the printing platform, prevent mucosal adhesion, and facilitate the separation of the structural layer from the sacrificial layer.

[0102] In the present invention, the wavelength of the ultraviolet light is 300 to 450 nm. For example, it can be 350 nm, 400 nm, 405 nm, 420 nm, etc.

[0103] In the present invention, the light intensity of the ultraviolet light is 2 to 100 mW / cm 2 , for example, it can be 5 mW / cm 2 , 8 mW / cm 2 , 10 mW / cm 2 , 12 mW / cm 2 , 14 mW / cm 2 , 15 mW / cm 2 , 20 mW / cm 2 , 30 mW / cm 2 , 40 mW / cm 2 , 80 mW / cm 2 , 90 mW / cm 2 , etc.

[0104] In some specific embodiments of the present invention, the alumina slurry uses the alumina ceramic slurry (material model: CA-100A) produced by Shenzhen Magic Square New Materials Co., Ltd.

[0105] Step 2)

[0106] The alumina ceramic lattice catalyst skeleton precursor obtained in step 1) is subjected to degreasing sintering to obtain the alumina ceramic lattice catalyst skeleton.

[0107] In the present invention, the degreasing sintering includes the following three stages:

[0108] The first stage is vacuum degreasing. The alumina ceramic lattice catalyst skeleton precursor is degreased, heat-preserved, and naturally cooled to room temperature in a tubular furnace under a vacuum environment to obtain the alumina ceramic lattice catalyst skeleton precursor-I;

[0109] The second stage is air vent degreasing. The alumina ceramic lattice catalyst skeleton precursor-I is degreased at high temperature again, heat-preserved, and naturally cooled to room temperature in a muffle furnace under an air environment to obtain the alumina ceramic lattice catalyst skeleton precursor-II;

[0110] In the third stage, it is air sintering. The alumina ceramic lattice catalyst skeleton precursor-II is sintered at a high temperature again in a muffle furnace under an air environment, kept warm, and naturally cooled to room temperature. Finally, a high-strength alumina ceramic lattice catalyst skeleton can be obtained.

[0111] In some specific embodiments of the present invention, in the first stage, the heating rate of degreasing is 0.5 - 5 °C / min, for example, it can be 1.0 °C / min, 1.2 °C / min, 1.4 °C / min, 1.5 °C / min, 1.6 °C / min, 1.8 °C / min, 2.0 °C / min, 2.5 °C / min, 3.0 °C / min, 3.5 °C / min, 4.0 °C / min, 4.5 °C / min, etc.

[0112] In some specific embodiments of the present invention, in the first stage, the temperature of degreasing is 400 - 800 °C, for example, it can be 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C, etc.

[0113] In some specific embodiments of the present invention, in the first stage, the holding time is 160 - 220 min, for example, it can be 165 min, 170 min, 175 min, 180 min, 185 min, 190 min, 195 min, 200 min, 205 min, 210 min, 215 min, etc.

[0114] In some specific embodiments of the present invention, in the second stage, the heating rate of degreasing is 0.5 - 5 °C / min, for example, it can be 1.0 °C / min, 1.2 °C / min, 1.4 °C / min, 1.5 °C / min, 1.6 °C / min, 1.75 °C / min, 1.8 °C / min, 2.0 °C / min, 2.5 °C / min, 3.0 °C / min, 3.5 °C / min, 4.0 °C / min, 4.5 °C / min, etc.

[0115] In some specific embodiments of the present invention, in the second stage, the temperature of degreasing is 800 - 1200 °C, for example, it can be 850 °C, 900 °C, 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C, etc.

[0116] In some specific embodiments of the present invention, in the second stage, the holding time is 20 - 80 min, for example, it can be 25 min, 30 min, 35 min, 40 min, 50 min, 60 min, 70 min, etc.

[0117] In some specific embodiments of the present invention, in stage three, the heating rate of degreasing is 2-8°C / min, for example, it can be 2.5°C / min, 3.0°C / min, 3.5°C / min, 4.0°C / min, 4.5°C / min, 5.0°C / min, 5.5°C / min, 6.0°C / min, 6.5°C / min, 7.0°C / min, 7.5°C / min, etc.

[0118] In some specific embodiments of the present invention, in stage three, the temperature of degreasing is 1400-1800°C, for example, it can be 1450°C, 1500°C, 1550°C, 1600°C, 1650°C, 1700°C, 1750°C, etc.

[0119] In some specific embodiments of the present invention, in stage three, the heat preservation time is 40-120 min, for example, it can be 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, etc.

[0120] Step 3)

[0121] Prepare an impregnating solution containing a metal salt, a zinc salt, and 2-methylimidazole for forming metal single atoms, put the alumina ceramic lattice catalyst skeleton into the impregnating solution, carry out ultrasonic impregnation, static standing, and filtration to obtain a metal single atom-loaded alumina ceramic lattice catalyst precursor.

[0122] In some specific embodiments of the present invention, the metal salt and the zinc salt can be dissolved in a solvent to obtain solution A, the 2-methylimidazole can be dissolved in a solvent to obtain solution B, and solution B is added to solution A to obtain the impregnating solution. Alternatively, solution A and B can be respectively placed in an ultrasonic reactor and ultrasonically dissolved for 3-5 min, and then mixed to obtain the impregnating solution.

[0123] In the present invention, the molar ratio of the metal salt, the zinc salt, and 2-methylimidazole is (0.1-10 mmol):(1-20 mmol):(10-120 mmol), for example, it can be 2 mmol:10 mmol:40 mmol.

[0124] In the present invention, the metal salt is one or more of acetylacetonate, acetate, ferrocene salt, or citrate of manganese, iron, nickel, or cobalt. For example, it can be manganese acetylacetonate.

[0125] In the present invention, the zinc salt is selected from one or more of zinc acetate, zinc nitrate, zinc chloride, zinc sulfate, and zinc carbonate.

[0126] In the present invention, the solvent is a C 1-6 alcohol solution, for example, it can be methanol, ethanol, isopropanol, etc. The solvents for solution A and solution B can be the same or different, and it is preferably to use the same solvent.

[0127] In some specific embodiments of the present invention, ultrasonic impregnation is carried out in an ultrasonic reactor, and the time of ultrasonic impregnation is 10 - 120 min, for example, it can be 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, etc.

[0128] In some specific embodiments of the present invention, the standing time is 12 - 96 hours, for example, it can be 20 hours, 24 hours, 30 hours, 36 hours, 40 hours, 42 hours, 48 hours, 50 hours, 54 hours, 60 hours, 66 hours, 70 hours, 72 hours, 80 hours, 84 hours, 90 hours, etc.

[0129] Step 4)

[0130] The alumina ceramic lattice catalyst precursor loaded with metal single atoms is subjected to a post - treatment process to obtain the alumina ceramic lattice catalyst loaded with metal single atoms.

[0131] In the present invention, the post - treatment process includes drying, anaerobic calcination, heat preservation, and natural cooling to room temperature.

[0132] In some specific embodiments of the present invention, drying is carried out in an oven, the drying temperature is 40 - 80 °C, for example, it can be 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, etc. The drying time is 10 - 60 min, for example, it can be 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, etc.

[0133] In some specific embodiments of the present invention, anaerobic calcination is carried out in an argon atmosphere in a tubular furnace.

[0134] In some specific embodiments of the present invention, the heating rate of calcination is 1 - 5 °C / min, for example, it can be 1.5 °C / min, 2.0 °C / min, 2.5 °C / min, 3.0 °C / min, 3.5 °C / min, 4.0 °C / min, 4.5 °C / min, etc.

[0135] In some specific embodiments of the present invention, the calcination temperature is 800 - 1200 °C, for example, it can be 850 °C, 900 °C, 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C, etc.

[0136] In some specific embodiments of the present invention, the heat preservation time is 1 - 5 hours, for example, it can be 1.5 hours, 2.0 hours, 2.5 hours, 3.0 hours, 3.5 hours, 4.0 hours, 4.5 hours, etc.

[0137] The present invention also provides the application of the metal single-atom loaded alumina ceramic lattice catalyst according to the foregoing or the metal single-atom loaded alumina ceramic lattice catalyst obtained by the foregoing preparation method in sewage treatment, preferably in the application of ozone catalytic oxidation water treatment.

[0138] Examples

[0139] The embodiments of the present invention will be described in detail below in conjunction with the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0140] Example 1: Preparation of manganese single-atom loaded alumina ceramic lattice catalyst

[0141] (1) Obtain a three-dimensional geometric configuration file with a three-period minimal surface structure of Gyroid lattice structure in a three-dimensional design software. Among them, the structural side length of the Gyroid lattice structure is 5 mm × 5 mm × 5 mm, the array period of the lattice unit cell is 2 × 2 × 2, and the relative density of the structure is 30%. Pour the alumina ceramic slurry (commercially available, manufacturer: Shenzhen Magic Cube New Materials Co., Ltd., model: CA-100A) into the liquid tank of the surface projection microstereolithography printer, import the designed three-dimensional geometric configuration file into the computer connected to the surface projection microstereolithography printer and perform slicing. Set the slice layer thickness to 20 μm, the ultraviolet light wavelength to 405 nm, the exposure time of the sacrificial layer to 3 - 8 seconds, and the ultraviolet light intensity to 15 mW / cm 2 ; the exposure time of the structural layer is 4 seconds, and the ultraviolet light intensity is 10 mW / cm 2 . Use the surface projection microstereolithography technology to cure layer by layer to obtain an alumina ceramic model (including the Gyroid lattice structure model and the sacrificial layer). Use a blade to peel the printed alumina ceramic model from the printer platform, and peel the sacrificial layer. Perform ultrasonic cleaning and water rinsing on the peeled alumina ceramic model for 60 minutes to remove the residual slurry inside the structure. After cleaning, place it on dust-free paper and dry it naturally for more than 24 hours to obtain the precursor of the alumina ceramic lattice catalyst skeleton.

[0142] (2) Perform three-stage degreasing sintering on the alumina ceramic lattice catalyst skeleton precursor obtained in step (1), Figure 2 Show the temperature control curve for degreasing sintering of the alumina ceramic lattice catalyst skeleton.

[0143] The first stage is vacuum degreasing. The alumina ceramic lattice catalyst skeleton precursor is degreased in a tubular furnace under a vacuum environment, heated to 600 °C at a rate of 1.6 °C / min, held for 180 min, and then naturally cooled to room temperature to obtain the alumina ceramic lattice catalyst skeleton precursor-I.

[0144] The second stage is air degreasing. The alumina ceramic lattice catalyst skeleton precursor-I is transferred to a muffle furnace under an air environment for high-temperature degreasing again. It is heated to 200 °C at a rate of 1.75 °C / min, then heated to 600 °C at a rate of 1 °C / min, held for 180 min, then heated to 1000 °C at a rate of 4 °C / min, held for 30 min, and then naturally cooled to room temperature to obtain the alumina ceramic lattice catalyst skeleton precursor-II.

[0145] The third stage is air sintering. The alumina ceramic lattice catalyst skeleton precursor-II is sintered at high temperature again in a muffle furnace under an air environment. It is heated to 1650 °C at a rate of 5 °C / min, held for 60 min, then cooled to 1200 °C at a rate of 5 °C / min, and then naturally cooled to room temperature. Finally, a high-strength alumina ceramic lattice catalyst skeleton can be obtained, with a porosity of 70% and a specific surface area of about 150 m 2 / g.

[0146] (3) Weigh 2 mmol of manganese acetylacetonate and 10 mmol of zinc nitrate hexahydrate solid powder and dissolve them in 30 mL of methanol to obtain solution A; weigh 40 mmol of 2-methylimidazole and dissolve it in 30 mL of methanol to obtain solution B. Place solutions A and B in an ultrasonic reactor and ultrasonically dissolve them for 5 min at 30 Hz. Quickly pour the dissolved solution B into solution A to obtain an impregnation solution. Weigh 5 g of the alumina ceramic lattice catalyst skeleton and add it to the impregnation solution, ultrasonically impregnate it for 60 min at 30 Hz, then let it stand for 72 hours, and filter to obtain the precursor of the metal single-atom loaded alumina ceramic lattice catalyst.

[0147] (4) Place the precursor of the metal single-atom loaded alumina ceramic lattice catalyst in an oven at 60 °C and dry it for 30 min, then place it in a tubular furnace under an argon atmosphere for anaerobic calcination. After heating to 900 °C at a rate of 5 °C / min, hold for 3 hours, and then take it out after natural cooling to obtain the manganese single-atom loaded alumina ceramic lattice catalyst (Mn single atom @ lattice).

[0148] Example 2

[0149] Using the same preparation method as in Example 1, change the Gyroid lattice structure in step (1) to the IWP lattice structure.

[0150] Example 3

[0151] Using the same preparation method as in Example 1, change the Gyroid lattice structure in step (1) to a Neovius lattice structure.

[0152] Comparative Example 1

[0153] Using the same preparation method as in Example 1, change the Gyroid lattice structure in step (1) to a square lattice structure.

[0154] Precursor of Alumina Ceramic Lattice Catalyst Skeleton

[0155] Figure 3 Presents the physical pictures of the alumina ceramic lattice catalyst skeletons precursors with four different configurations obtained by 3D printing using surface projection microstereolithography technology in Examples 1-3 and Comparative Example 1.

[0156] Alumina Ceramic Lattice Catalyst Skeleton

[0157] Figure 4 Presents the physical pictures of the alumina ceramic lattice catalyst skeletons obtained by debinding and sintering in Examples 1-3 and Comparative Example 1. Among them, Figure 4 a) of shows the alumina ceramic lattice catalyst skeleton precursors-I with four different configurations obtained after the first stage (vacuum debinding) treatment; Figure 4 b) of shows the alumina ceramic lattice catalyst skeletons with four different configurations obtained after the second stage (ventilated debinding) and the third stage (ventilated sintering) treatments.

[0158] Manganese Single-Atom Loaded Alumina Ceramic Lattice Catalyst

[0159] Figure 5 Presents the physical pictures of the manganese single-atom loaded alumina ceramic lattice catalysts with four different configurations prepared in Examples 1-3 and Comparative Example 1.

[0160] Scanning Electron Microscope Test

[0161] Perform microscopic property analysis on the catalyst prepared in Example 1, and scrape the surface powder for sample preparation at the same time. The results are shown in Figure 6 a) and b) of. It can be seen from Figure 6 a) of that it has a microporous structure; Figure 6 It can be seen from b) of that it has a surface nano-site structure.

[0162] Aberration-Corrected Electron Microscope Test

[0163] Scrape the surface powder of the catalyst prepared in Example 1 for sample preparation, and perform spherical aberration electron microscopy test (HAADF-STEM). The results are shown in Figure 7 . Figure 7The position of the bright spot in the circle is the site where manganese single atoms exist, which proves that manganese in the form of single atoms has been successfully loaded on the surface of the alumina ceramic lattice catalyst skeleton.

[0164] Uniaxial Compression Experiment

[0165] Uniaxial compression experiments were respectively carried out on the alumina ceramic lattice catalyst skeleton samples after printing, vacuum debinding, and sintering treatment in Examples 1 - 3 and Comparative Example 1, and the results are shown in Figure 8 a) - d) of. It can be seen from the stress - strain curves in the figure that the compressive strengths of the alumina ceramic lattice catalyst skeletons after debinding and sintering treatment in Examples 1 - 3 are 56.0, 49.9, and 67.3 MPa respectively, which are increased to 19.0, 15.8, and 11.6 times that of the structure after printing (the compressive strengths are 3.0, 3.2, and 5.8 MPa respectively).

[0166] Finite Element Analysis (Computational Fluid Dynamics)

[0167] Taking the square lattice structure as a control, the permeability and mass transfer performance of the designed Gyroid lattice structure, IWP lattice structure, and Neovius lattice structure were calculated using CAD software and finite element analysis software, and combined with the measured specific surface area, the results are shown in Figure 9 . Based on the comprehensive analysis of the surface area test data and mass transfer results of various structures, all kinds of triply periodic minimal surface lattice structures show significantly better specific surface area and permeability than the square lattice structure.

[0168] Comparative Example 2

[0169] The synthesis method of the alumina ceramic lattice catalyst (gyroid configuration) loaded with manganese nanoclusters is as follows:

[0170] Using the same preparation method as in Example 1, the amount of manganese acetylacetonate added in step (3) was changed to 6 mmol. The rest of the operations remained unchanged, and the alumina ceramic lattice catalyst loaded with manganese nanoclusters (Mn nanoclusters @ lattice) was obtained.

[0171] Comparative Example 3

[0172] The synthesis method of the alumina ceramic spherical catalyst loaded with manganese single atoms is as follows:

[0173] Weigh 2 mmol of manganese acetylacetonate and 10 mmol of zinc nitrate hexahydrate solid powder and dissolve them in 30 mL of methanol to obtain solution A; weigh 40 mmol of 2-methylimidazole and dissolve it in 30 mL of methanol to obtain solution B. Place solutions A and B in an ultrasonic reactor respectively and ultrasonically dissolve them for 5 min at 30 Hz. Quickly pour the dissolved solution B into solution A to obtain an impregnation solution. Weigh 5 g of alumina ceramic spheres (model A820850, particle size 3 - 5 mm, purchased from Shanghai Macklin Biochemical Technology Co., Ltd.) and add them to the impregnation solution. Ultrasonically impregnate for 60 min at 30 Hz, then let it stand for 72 hours, and filter to obtain a precursor of an alumina ceramic spherical catalyst loaded with manganese single atoms.

[0174] Then place the precursor of the alumina ceramic spherical catalyst loaded with manganese single atoms in an oven at 60 °C and dry it for 30 min. Then place it in a tubular furnace and carry out anaerobic calcination under an argon atmosphere. Heat it to 900 °C at a rate of 5 °C / min, hold for 3 hours, and then take it out after natural cooling to obtain an alumina ceramic spherical catalyst loaded with manganese single atoms (Mn single atom @ spheres)

[0175] Comparative Example 4

[0176] The synthesis method of an alumina ceramic spherical catalyst loaded with manganese nanoclusters is as follows:

[0177] Adopt the same preparation method as in Comparative Example 3, and change the amount of manganese acetylacetonate added to 6 mmol. Keep the rest of the operations unchanged to obtain an alumina ceramic spherical catalyst loaded with manganese nanoclusters (Mn nanoclusters @ spheres).

[0178] Example 4: Application of the catalyst in simulated sewage treatment

[0179] (1) Select oxalic acid as the model pollutant and degrade it by the method of ozone catalytic oxidation. Prepare 200 mL of an oxalic acid aqueous solution with a concentration of 100 mg / L as simulated wastewater. Set up the device as shown in Figure 10 for ozone catalytic oxidation of sewage treatment. The lower part of the reaction device is the sewage inlet, and the upper part is the sewage outlet; fill the acrylic chamber with the catalyst for degradation. In the experiment, the simulated wastewater flows into the reactor from the Figure 10 lower port of the reactor and flows out from the upper port and returns to form a cyclic reaction.

[0180] Fill the catalyst prepared in Example 1 in the acrylic chamber. During the reaction, the oxygen intake is 0.2 L / min, the ozone concentration generated by the ozone generator is 8 mg / L, and the degradation time is 60 min.

[0181] (2) Take 1 mL of water sample at 0, 2, 5, 10, 20, 30, 45, and 60 min of the reaction. After filtering through a 45-μm filter membrane, inject it into a chromatographic vial and wait for subsequent testing.

[0182] (3) Analyze the water sample using a high-performance liquid chromatograph (brand: Agilent, model: 1260 Infinity II). The detector is an ultraviolet detector (wavelength 210 nm), and the mobile phase is 20 mM sodium dihydrogen phosphate buffer. After analysis, organize the concentration data and plot the degradation curve for 60 min.

[0183] Replace the catalyst prepared in Example 1 with the manganese nanocluster-loaded alumina ceramic lattice catalyst (gyroid configuration) prepared in Comparative Example 2, the manganese single-atom-loaded alumina ceramic spherical catalyst prepared in Comparative Example 3, and without using a catalyst, and conduct tests using the same apparatus and test conditions as above.

[0184] Results

[0185] Figure 11 The comparative diagram of the degradation curves of the simulated wastewater for ozone catalytic oxidation of sewage treatment using the catalysts prepared in Example 1 and Comparative Examples 2-3 and without using a catalyst is shown. It can be seen from the figure that the catalyst in Example 1 has the best degradation effect, and the pollutant removal rate reaches 90% within 60 minutes; while the degradation effect of the manganese nanocluster-loaded alumina ceramic lattice catalyst in Comparative Example 2 or the manganese single-atom-loaded alumina ceramic spherical catalyst in Comparative Example 3 has decreased, and the pure ozone system hardly has any degradation.

[0186] Example 5: Application of the catalyst in actual sewage treatment

[0187] (1) Select actual coal chemical wastewater as the model pollutant and degrade it using the method of ozone catalytic oxidation. Select 300 mL of coal chemical wastewater with an initial concentration of 110 mg / L for degradation. Also use Figure 10 the shown apparatus, and the catalyst used is the catalyst prepared in Example 1. During the reaction, the oxygen inlet volume is 0.5 L / min, the ozone concentration generated by the ozone generator is 15 mg / L, and the degradation time is 60 min.

[0188] (2) Take 7 mL of water sample at 0, 2, 5, 10, 20, 30, 45, and 60 min of the reaction. After filtering through a 45-μm filter membrane, inject it into a chromatographic vial and wait for subsequent testing.

[0189] (3) Use a Lianhua water quality tester to conduct COD (chemical oxygen demand) tests. For the water samples obtained during the degradation process, conduct COD tests on them and plot the corresponding degradation curves for analysis.

[0190] The catalysts prepared in Example 1 were respectively replaced with the manganese single-atom-loaded alumina ceramic spherical catalyst prepared in Comparative Example 3 and the manganese nanocluster-loaded alumina ceramic spherical catalyst prepared in Comparative Example 4, and the actual sewage treatment tests were carried out using the same device and test conditions as above.

[0191] Results

[0192] Figure 12 The comparison chart of the degradation curves of the actual wastewater in the ozonation catalytic oxidation of sewage by the catalysts prepared in Example 1 and Comparative Examples 3-4 is shown. It can be seen from the figure that the Mn single-atom lattice catalyst in Example 1 has the best degradation effect, and the COD can be reduced to below 50 mg / L within 60 minutes. The degradation effects of the manganese single-atom-loaded alumina ceramic spherical catalyst in Comparative Example 3 and the manganese nanocluster-loaded alumina ceramic spherical catalyst in Comparative Example 4 are inferior, and the effluent COD is higher than that in Example 1.

[0193] Three-Dimensional Fluorescence Experiment

[0194] Figure 13 The three-dimensional fluorescence experimental results of the actual wastewater in the ozonation catalytic oxidation of sewage by the catalyst of Example 1 are shown. Figure a) is the three-dimensional fluorescence result of the raw water, and Figure b) is the result after 60 minutes of treatment. It can be seen that after 60 minutes of treatment, the removal rate of the fluorescent substances is very high, which proves that the Mn single-atom lattice catalyst has a very high pollutant removal efficiency.

[0195] Cyclic Test Experiment

[0196] The operation in Example 5 was repeated for five cycles (each cycle time was 60 min), and the results are shown in Figure 14 . It can be seen from the figure that the effluent concentration of COD is all below 50 mg / L, indicating that the catalyst prepared in Example 1 has high activity and high stability and can be repeatedly used for sewage treatment for multiple cycles.

[0197] Example 6: Exploration of the mechanism of the manganese single-atom lattice catalyst for degrading pollutants

[0198] Combined with the method of computational chemistry, ab initio molecular dynamics simulation was used to explore the process of generating reactive oxygen species at the manganese single-atom site using the CP2K software. The parameters of the simulation process are as follows: The core electrons are described by the norm-conserving Goedecker-Teter-Hutter (GTH) pseudopotential. The convergence criterion is 1.0×10 -6 a.u. The Nose-Hoover thermostat was used in the canonical ensemble (NVT), the time step was 0.5 fs, and the finite temperature was 298 K.

[0199] Results

[0200] Figure 15 The process of reactive oxygen species generation is shown. The whole reaction process between manganese single-atom sites and ozone (O3) was simulated, and the results showed that more reactive oxygen species were generated by the reaction of manganese single-atom sites with O3 for pollutant degradation. The specific process is as follows: First, the initial state was verified, and the distance between O3 and the carbon skeleton was Subsequently, the ozone molecule gradually approached the carbon plane. After ~279 fs, it initially reached the reaction site on the catalyst surface; after continuous configuration adjustment of O3, the configuration flip was completed after ~101 fs, and a bond was formed close to the surface hydroxyl group; ·HO3 was gradually generated and served as an intermediate after the transition state, and finally left the carbon skeleton; finally, after another 78 fs, the intermediate was converted into two reactive oxygen species: ·OH and O2. The simulation results showed that the process of generating reactive oxygen species such as ·OH was thermodynamically spontaneous, proving that manganese single-atom sites could promote the generation of reactive oxygen species such as ·OH, thereby improving the removal efficiency of pollutants and achieving efficient advanced wastewater treatment.

[0201] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A metal single-atom loaded alumina ceramic lattice catalyst, characterized in that, Comprising: An alumina ceramic lattice catalyst skeleton having a three - periodic minimal surface structure; And Metal single atoms supported on the alumina ceramic lattice catalyst skeleton.

2. The catalyst according to claim 1, characterized in that, The metal single atoms are selected from one or more of manganese, iron, nickel, and cobalt; Wherein, the loading amount of the metal single atoms is 0.05 - 3.0 wt%.

3. The catalyst according to claim 1 or 2, characterized in that, The three - periodic minimal surface structure is a Gyroid lattice structure, an IWP lattice structure, or a Neovius lattice structure; Preferably, the side length of the relative density structure of the three - periodic minimal surface structure is (2 - 20) mm×(2 - 20) mm×(2 - 20) mm; the array period of the lattice unit cell of the three - periodic minimal surface structure is (1 - 20)×(1 - 20)×(1 - 20); the relative density of the three - periodic minimal surface structure is 20 - 80%.

4. The catalyst according to any one of claims 1 - 3, wherein The porosity of the alumina ceramic lattice catalyst skeleton is 20% - 80%; The specific surface area of the alumina ceramic lattice catalyst skeleton is 10 m 2 / g - 200 m 2 / g; The compressive strength of the alumina ceramic lattice catalyst skeleton is 5 MPa - 300 MPa.

5. The preparation method of the catalyst according to any one of claims 1-4, characterized in that, Comprising the following steps: (1) Obtaining a precursor of an alumina ceramic lattice catalyst skeleton by 3D printing through surface - projection micro - stereolithography technology; (2) Debinding and sintering the precursor of the alumina ceramic lattice catalyst skeleton to obtain the alumina ceramic lattice catalyst skeleton; (3) Preparing an impregnation solution containing a metal salt, a zinc salt, and 2 - methylimidazole for forming metal single atoms, placing the alumina ceramic lattice catalyst skeleton into the impregnation solution, performing ultrasonic impregnation, standing, and filtering to obtain a precursor of a metal - single - atom - loaded alumina ceramic lattice catalyst; (4) Subjecting the precursor of the metal - single - atom - loaded alumina ceramic lattice catalyst to a post - treatment process to obtain the metal - single - atom - loaded alumina ceramic lattice catalyst.

6. The preparation method according to claim 5, characterized in that, In step (1), Determining a three - dimensional geometric configuration file with a three - periodic minimal surface structure in three - dimensional design software; pouring alumina slurry into the liquid tank of a 3D printer, importing the three - dimensional geometric configuration file into the computer connected to the 3D printer for slicing, and then performing 3D printing by layer - by - layer curing under ultraviolet light; Wherein, the layer thickness of the slicing is 5 - 50 μm; the exposure time for each layer is 1 - 10 seconds; The wavelength of the ultraviolet light is 300 to 450 nm; the light intensity of the ultraviolet light is 2 to 100 mW / cm 2 .

7. The preparation method according to claim 5 or 6, characterized in that, In step (2), the debinding and sintering includes the following three stages: Stage 1: Debinding, heat - insulating, and cooling the precursor of the alumina ceramic lattice catalyst skeleton to room temperature to obtain the precursor - I of the alumina ceramic lattice catalyst skeleton; Wherein, stage 1 is carried out in a vacuum environment, the heating rate of debinding is 0.5 - 5 °C / min; the temperature of debinding is 400 - 800 °C; the heat - insulating time is 160 - 220 min; Stage 2: Debinding, heat - insulating, and cooling the precursor - I of the alumina ceramic lattice catalyst skeleton to room temperature to obtain the precursor - II of the alumina ceramic lattice catalyst skeleton; Among them, the second stage is carried out in an air environment. The heating rate of degreasing is 0.5 - 5 °C / min, the temperature of degreasing is 800 - 1200 °C, and the holding time is 20 - 80 min; Stage three: sinter, hold, and cool the alumina ceramic lattice catalyst precursor-II to room temperature to obtain an alumina ceramic lattice catalyst; Among them, the third stage is carried out in an air environment. The heating rate of sintering is 2 - 8 °C / min, the temperature of sintering is 1400 - 1800 °C, and the holding time is 40 - 120 min.

8. The preparation method according to any one of claims 5 to 7, characterized in that, In step (3), the molar ratio of the metal salt, zinc salt, and 2-methylimidazole is (0.1 - 10 mmol):(1 - 20 mmol):(10 - 120 mmol); Among them, the metal salt is one or more of acetylacetonate, acetate, ferrocene salt, or citrate of manganese, iron, nickel, or cobalt; The zinc salt is selected from one or more of zinc acetate, zinc nitrate, zinc chloride, zinc sulfate, and zinc carbonate; The time of ultrasonic impregnation is 10 - 120 min; the time of standing is 12 - 96 hours.

9. The preparation method according to any one of claims 5 to 8, characterized in that, In step (4), the post-treatment process includes drying, anaerobic calcination, holding, and cooling to room temperature; Among them, The temperature of drying is 40 - 80 °C; the time of drying is 10 - 60 min; The heating rate of calcination is 1 - 5 °C / min; the temperature of calcination is 800 - 1200 °C; the holding time is 1 - 5 hours.

10. Use of the metal single-atom loaded alumina ceramic lattice catalyst according to any one of claims 1 - 4 or the metal single-atom loaded alumina ceramic lattice catalyst obtained by the preparation method according to any one of claims 5 - 9 in sewage treatment, preferably in ozonation catalytic oxidation water treatment.

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