Oxygen-rich vacancy nanometer island catalyst and preparation method thereof

Abstract

The application discloses an oxygen-enriched vacancy nano-island catalyst and a preparation method thereof. A catalyst carrier material and a first catalyst support are mixed according to a molar ratio of 1:(0.05-0.5), and are added into a ball milling jar. Ball milling beads and a citric acid solution are added, the ball milling jar is vacuumized or is filled with a protective gas, and then is placed on a ball mill for ball milling to obtain material A. A second catalyst support is added into the ball milling jar, and the molar ratio of the material A to the second catalyst support is 1:(0.01-0.05). Then, the ball milling jar is vacuumized or is filled with a protective gas for ball milling to obtain material B. The material B is dried in a vacuum environment and is calcined in a protective gas to obtain a defect-enriched supported catalyst. The mechanical force of vacuum ball milling directly destroys the material lattice, causes the surface and bulk oxygen atoms to be forced to peel off, forms a large number of oxygen vacancies, and the oxygen vacancies have a higher concentration and a more uniform distribution. The high oxygen vacancy density can significantly improve the low-temperature catalytic activity.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically, it relates to an oxygen-rich vacancy nanoisland catalyst and its preparation method. Background Technology

[0002] Waste-to-energy incineration has become the mainstream method for the harmless treatment of waste in my country. However, municipal solid waste has a complex composition, and the flue gas produced by its combustion usually contains various highly toxic pollutants such as NO and chlorinated organic compounds. Currently, numerous studies have demonstrated that the synergistic removal of multiple pollutants is theoretically feasible; therefore, using a single catalyst for the synergistic removal of CVOCs and NOx is a promising strategy. However, in the synergistic control of multiple pollutants, catalysts face more complex environments, and catalyst design presents more severe challenges. Numerous studies have shown that the operating temperature window of the NH3-SCR reaction is typically lower than that of the CB catalytic oxidation. Therefore, modifying the catalyst to achieve the synergistic removal of NOx and CB within a similar operating temperature window is an important factor to consider in catalyst design.

[0003] The unique structure and defects of catalysts, such as the generation of oxygen vacancies (OVs), are one effective strategy to address the aforementioned problems, improving performance by simultaneously altering electronic structure and surface reactivity. OVs are generally considered to play a crucial role in activating the benzene ring or C-Cl bond of chlorinated organic compounds such as chlorobenzene, promoting dechlorination and subsequent dissociation or transformation, thus lowering their transformation temperature and coinciding with the NO temperature window. Although oxygen vacancies are widely recognized as active sites in oxide-based catalysts, our understanding of how they are stably and uniformly formed during catalyst preparation is limited.

[0004] Currently, supported catalysts are mostly prepared using methods such as hydrothermal synthesis, impregnation, co-precipitation, and ion exchange. However, most of these methods are not suitable for large-scale catalyst preparation and are more appropriate for precise control of catalyst structure in the laboratory. Furthermore, there is limited research on catalysts for the synergistic removal of NOx and CB from waste incineration flue gas. Therefore, based on the construction strategy of defect-rich supported catalyst systems, proposing a preparation strategy that yields a catalyst with high activity and selectivity, and is easily scalable for industrial application, has significant practical implications. Summary of the Invention

[0005] To address at least one of the aforementioned problems, this invention provides an oxygen-rich vacancy nanoisland catalyst and its preparation method, wherein the oxygen-rich vacancy nanoisland catalyst is prepared by stepwise ball milling followed by calcination under vacuum conditions or a specific atmosphere.

[0006] To achieve the above objectives, the present invention employs the following technical means: This invention provides an oxygen-rich vacancy nanoisland catalyst and its preparation method, comprising the following steps: S1. The catalyst support material and the first catalyst loading are mixed at a molar ratio of 1:(0.05-0.5), added to a ball mill jar, and ball milling beads and citric acid solution are added. After the ball mill jar is evacuated or a protective gas is introduced, it is placed on a ball mill for ball milling to obtain material A. S2. Add the second catalyst support to the ball mill jar. The molar ratio of material A to the second catalyst support is 1:(0.01-0.05). Then, evacuate the ball mill jar or introduce a protective gas and ball mill to obtain material B. S3. Dry material B in a vacuum environment and calcine it under a protective gas to obtain a defect-rich supported catalyst. The catalyst support material is one or more of the following: cerium nitrate, titanium dioxide, honeycomb framework nickel, and porous carbon materials. The first catalyst support and the second catalyst support are selected from one of manganese nitrate, cobalt nitrate, iron nitrate, copper nitrate, and ruthenium chloride, respectively, and the first catalyst support and the second catalyst support are of different types.

[0007] In some embodiments of the present invention, the concentration of the citric acid solution is 0.01-0.1 mol / L.

[0008] In some embodiments of the present invention, in step S1, the ball milling conditions are: ball milling speed 500-600 r / min, ball milling time 4-6 hours.

[0009] In some embodiments of the present invention, in step S2, the ball milling conditions are: ball milling speed 50-200 r / min, ball milling time 0.2-1 hour.

[0010] In some embodiments of the present invention, in step S1, the mass ratio of the mixture of catalyst support material and first catalyst load in the ball mill jar to the ball milling beads is (0.5-2.5):(10-15).

[0011] In some embodiments of the present invention, the mixture of the catalyst support material and the first catalyst load occupies 1 / 3 of the volume of the ball mill jar.

[0012] In some embodiments of the present invention, the protective gas is one of nitrogen, argon, or 3% hydrogen.

[0013] In some embodiments of the present invention, the drying temperature in S3 is 60-90°C and the drying time is 10-24 hours.

[0014] In some embodiments of the present invention, the calcination temperature in step S3 is 350-500°C and the calcination time is 2-5 hours.

[0015] A second aspect of the present invention provides an oxygen-rich vacancy nanoisland catalyst prepared according to the method described in the first aspect.

[0016] This invention also provides the application of the oxygen-rich vacancy nanoisland catalyst described in the second aspect in the synergistic catalytic degradation of gaseous pollutants, including nitrogen oxides and chlorinated organic compounds. It can be applied to the degradation of atmospheric pollutants, and also to the synergistic catalysis of multiple pollutants in waste incineration flue gas.

[0017] In some embodiments of the present invention, the temperature range for the synergistic catalytic degradation of the composite catalyst is 90-350°C.

[0018] In some embodiments of the present invention, the application process is as follows: the composite catalyst is placed in a programmed temperature fixed bed and the synergistic catalytic degradation of nitrogen oxides and chlorinated organic compounds is carried out in a temperature range of 90-350°C.

[0019] Beneficial effects of the present invention Compared with the prior art, the present invention has the following beneficial effects: This invention provides an oxygen-rich vacancy nanoisland catalyst via a simplified ball milling method. The catalyst is prepared by ball milling a mixture of materials under a specific atmosphere, followed by sintering under an inert atmosphere. The ball milling process is simple and can be mass-produced. This application utilizes the mechanical force of vacuum ball milling to directly disrupt the material's crystal lattice, forcibly stripping surface and bulk oxygen atoms to form a large number of oxygen vacancies with higher concentration and more uniform distribution. This high oxygen vacancy density significantly enhances low-temperature catalytic activity. Furthermore, the distributed ball milling method employed in this invention ensures the catalyst exists in a nanoisland-like structure, offering advantages such as simplicity, safety, environmental friendliness, and low cost. The catalyst also exhibits high synergistic catalytic performance, simultaneously catalyzing the degradation of nitrogen oxides and chlorinated organic compounds within a temperature range of 90-350℃. Attached Figure Description

[0020] Figure 1 A transmission electron microscope image of the catalyst prepared in Example 1 of the present invention is shown; Figure 2 A transmission electron microscope image of the catalyst prepared in Example 2 of the present invention is shown; Figure 3 A transmission electron microscope image of the catalyst prepared in Example 3 of the present invention is shown; Figure 4 A transmission electron microscope image of the catalyst prepared in Example 4 of the present invention is shown; Figure 5 A transmission electron microscope image of the catalyst prepared in Example 5 of the present invention is shown; Figure 6A transmission electron microscope image of the catalyst prepared in Example 6 of the present invention is shown; Figure 7 The diagram shows the degradation efficiency of chlorine-containing organic compounds catalyzed by the catalysts prepared in Examples 1-6 of this invention. Figure 8 The diagram shows the NOx degradation efficiency of the catalysts prepared in Examples 1-6 of this invention. Figure 9 The diagram shows the degradation efficiency of chlorine-containing organic compounds catalyzed by the catalysts prepared in Comparative Examples 1-5 of this invention. Figure 10 The diagram shows the synergistic catalytic NOx degradation efficiency of the catalysts prepared in Comparative Examples 1-5 of this invention; Figure 11 A schematic diagram of the catalyst structure prepared according to the present invention is shown; Figure 12 The O2-TPD results of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention are shown. Detailed Implementation

[0021] The following examples are used to illustrate preferred embodiments of the invention. Those skilled in the art will understand that the techniques disclosed in the examples represent techniques discovered by the inventors that can be used to implement the invention, and therefore can be considered preferred embodiments for implementing the invention. However, those skilled in the art should understand from this specification that many modifications can be made to the specific embodiments disclosed herein, still yielding the same or similar results, without departing from the spirit or scope of the invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and all materials disclosed herein are incorporated herein by reference. Many equivalent techniques of specific embodiments of the invention described herein will be recognized or can be understood by those skilled in the art through conventional experimentation. These equivalents will be included in the claims.

[0023] An oxygen-rich vacancy nanoisland catalyst and its preparation method include the following steps: S1. The catalyst support material and the first catalyst loading are mixed at a molar ratio of 1:(0.05-0.5) and added to a ball mill jar. Grinding balls and a 0.01-0.1 mol / L citric acid solution are added. The mass ratio of the mixture of catalyst support material and the first catalyst loading to the grinding balls in the ball mill jar is (0.5-2.5):(10-15). The mixture of catalyst support material and the first catalyst loading occupies 1 / 3 of the volume of the ball mill jar. After evacuating the ball mill jar or introducing a protective gas, it is placed on a ball mill for ball milling at a speed of 500-600 r / min for 4-6 hours to obtain material A. S2. Add the second catalyst support to the above ball mill jar. The molar ratio of material A to the second catalyst support is 1:(0.01-0.05). Then, evacuate the ball mill jar or introduce protective gas and ball mill: ball milling speed 50-200 r / min, ball milling time 0.2-1 hour, to obtain material B. S3. Dry material B in a vacuum environment: temperature 60-90℃, drying time 10-24 hours, and calcine it under a protective gas: temperature 350-500℃, calcine time 2-5 hours, to obtain the defect-rich supported catalyst. The catalyst support material is one or more of cerium nitrate, titanium dioxide, honeycomb framework nickel, and porous carbon material; the first catalyst support and the second catalyst support are selected from manganese nitrate, cobalt nitrate, iron nitrate, copper nitrate, and ruthenium chloride, respectively, and the types of the first catalyst support and the second catalyst support are different; the protective gas is one of nitrogen, argon, and 3% hydrogen.

[0024] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0025] Example 1: Preparation of the catalyst CeO2-Mn2@Ru1 Step S1: Weigh 0.8865 g of manganese nitrate and 8 g of cerium nitrate according to a manganese to cerium molar ratio of 0.2:1; and place them together in a ball mill jar. Evacuate the jar to a vacuum degree of 0.1 using a vacuum pump. The ball milling parameters are set as follows: ball-to-powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, and time 5 h, to obtain material A after preliminary ball milling.

[0026] In step S2, 0.037 g of ruthenium chloride was weighed according to a ruthenium to cerium molar ratio of 0.01:1, and the second loading material, ruthenium chloride, was added to the ball mill jar. A vacuum pump was used to evacuate the mill to a vacuum level of 0.1. The ball milling parameters were adjusted to a rotation speed of 200 rpm and a time of 1 hour to obtain the final ball-milled material B.

[0027] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain an oxygen-rich vacancy catalyst, denoted as CeO2-Mn5@Ru1.

[0028] Example 2 Preparation of the catalyst CeO2-Mn2@Fe1 Step S1: Weigh 0.8865 g of manganese nitrate and 8 g of cerium nitrate according to a manganese to cerium mass ratio of 0.2:1; 5 mL of 0.1 mol / L citric acid solution and place them together in a ball mill jar. Use a vacuum pump to evacuate to a vacuum degree of 0.1. The ball milling parameters are set as follows: ball powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, time 6 h, to obtain material A after preliminary ball milling.

[0029] In step S2, according to the iron to cerium molar ratio of 0.01:1, 0.0713g of ferric nitrate was weighed, the second loading material ferric nitrate was added to the ball mill jar, and the vacuum was evacuated to a vacuum degree of 0.1 using a vacuum pump. The ball milling parameters were adjusted to a rotation speed of 200 rpm and a time of 1 h to obtain the final ball-milled material B.

[0030] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain an oxygen-rich vacancy catalyst, denoted as CeO2-Mn5@Fe1.

[0031] Example 3: Preparation of the catalyst CeO2-Mn2@Cu1 Step S1: Weigh 0.222g of manganese nitrate and 8g of cerium nitrate according to a manganese to cerium molar ratio of 0.05:1. Place them together in a ball mill jar and evacuate to a vacuum degree of 0.1 using a vacuum pump. The ball milling parameters are set as follows: ball powder mass ratio of 15:1, zirconium oxide balls 5mm:10mm=1:1, rotation speed 600rpm, and time 6h to obtain material A after preliminary ball milling.

[0032] In step S2, according to the copper to cerium molar ratio of 0.01:1, 0.0427g of copper nitrate was weighed; the second loading material, copper nitrate, was added to the ball mill jar, and a vacuum pump was used to evacuate the jar to a vacuum degree of 0.1; the ball milling parameters were adjusted to a rotation speed of 200 rpm and a time of 1 h, to obtain the final ball-milled material B.

[0033] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain an oxygen-rich vacancy catalyst, denoted as CeO2-Mn5@Cu1.

[0034] Example 4: Preparation of the catalyst TiO2-Mn2@Fe1 Step S1: Weigh 0.8865 g of manganese nitrate and 8 g of titanium dioxide, along with 5 mL of 0.01 mol / L citric acid solution, in a molar ratio of 0.2:1. Place them together in a ball mill jar and evacuate to a vacuum degree of 0.1 using a vacuum pump. Set the ball milling parameters to a ball-to-powder mass ratio of 15:1, with zirconium oxide balls of 5 mm:10 mm = 1:1, a rotation speed of 600 rpm, and a time of 6 h to obtain material A after preliminary ball milling.

[0035] In step S2, iron and titanium dioxide are mixed at a molar ratio of 0.01:1. 0.07134 g of ferric nitrate is weighed, the second loading material ferric nitrate is added to the ball mill jar, and a vacuum pump is used to evacuate the jar to a vacuum degree of 0.1. The ball milling parameters are adjusted to a rotation speed of 200 rpm and a time of 1 h to obtain the final ball-milled material B.

[0036] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain an oxygen-rich vacancy catalyst, denoted as TiO2-Mn5@Fe1.

[0037] Example 5: Preparation of the catalyst CeO2-Mn5@Ru1 Step S1: Weigh 2.216 g of manganese nitrate and 8 g of cerium nitrate according to a molar ratio of 0.5:1; and place 5 mL of 0.1 mol / L citric acid solution together in a ball mill jar. Use a vacuum pump to evacuate to a vacuum degree of 0.1. The ball milling parameters are set as follows: ball powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, and time 6 h to obtain material A after preliminary ball milling.

[0038] In step S2, ruthenium and cerium are mixed at a molar ratio of 0.01:1, and 0.0366 g of ruthenium chloride is weighed. Then, the ball mill jar is opened and the second loading material, ruthenium chloride, is added. A vacuum pump is used to evacuate the jar to a vacuum degree of 0.1. The ball milling parameters are adjusted to a rotation speed of 200 rpm and a time of 1 hour to obtain the final ball-milled material B.

[0039] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain an oxygen-rich vacancy catalyst, denoted as CeO2-Mn5@Ru1.

[0040] Example 6: Preparation of the catalyst CeO2-Mn5@Ru5 Step S1: Weigh 2.216 g of manganese nitrate and 8 g of cerium nitrate according to a molar ratio of 0.5:1; and place 5 mL of 0.1 mol / L citric acid solution together in a ball mill jar. Use a vacuum pump to evacuate to a vacuum degree of 0.1. The ball milling parameters are set as follows: ball powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, and time 6 h to obtain material A after preliminary ball milling.

[0041] In step S2, ruthenium and cerium are mixed at a molar ratio of 0.05:1, and 0.183 g of ruthenium chloride is weighed. Then, the ball mill jar is opened and the second loading material, ruthenium chloride, is added. A vacuum pump is used to evacuate the jar to a vacuum level of 0.1. The ball milling parameters are adjusted to a rotation speed of 200 rpm and a time of 1 hour to obtain the final ball-milled material B.

[0042] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain the catalyst, denoted as CeO2-Mn5@Ru5.

[0043] Comparative Example 1: Preparation of the catalyst CeMn@Ru Step S1: Manganese and cerium are weighed at a molar ratio of 0.2:1. 0.8865 g of manganese nitrate and 8 g of cerium nitrate are weighed and placed together in a ball mill jar with 5 mL of 0.1 mol / L citric acid solution. The ball milling parameters are set as follows: ball-to-powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, and time 5 h to obtain material A after preliminary ball milling.

[0044] In step S2, ruthenium and cerium are mixed at a molar ratio of 0.01:1, and 0.0366 g of ruthenium chloride is weighed out. Then, the second loading material, ruthenium chloride, is added to the ball mill jar, with the ball milling parameters remaining unchanged, to obtain the final ball-milled material B.

[0045] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain the catalyst, denoted as CeMn@Ru.

[0046] Comparative Example 2: Preparation of CeMn-Ru catalyst Step S1: Manganese and cerium are weighed at a molar ratio of 0.2:1. 0.8865 g of manganese nitrate and 8 g of cerium nitrate are weighed and placed together with 5 mL of deionized water in a ball mill jar. The ball milling parameters are set as follows: ball-to-powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, time 5 h, to obtain material A after preliminary ball milling.

[0047] In step S2, 0.0366 g of ruthenium chloride is weighed according to the molar ratio of ruthenium to cerium of 0.01:1. The second loading material, ruthenium chloride, is added to the ball mill jar, while the ball milling parameters remain unchanged, to obtain the final ball-milled material B.

[0048] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain the catalyst, denoted as CeMn-Ru.

[0049] Preparation of CeMn / Ru catalyst (Comparative Example 3) Step S1: Manganese and cerium are weighed at a molar ratio of 0.2:1. 0.8865 g of manganese nitrate and 8 g of cerium nitrate are added, along with 5 mL of 0.1 mol / L citric acid solution. The mixture is placed in a ball mill jar and evacuated to a vacuum degree of 0.1 using a vacuum pump. The ball milling parameters are set as follows: ball-to-powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed 600 rpm, and time 5 h. Material A after preliminary ball milling is obtained.

[0050] In step S2, ruthenium and cerium are weighed at a mass ratio of 0.01:1, and 0.0366g of ruthenium chloride is added. The ball mill jar is opened and the second loading material, ruthenium chloride, is added. The vacuum is evacuated to a vacuum degree of 0.1 using a vacuum pump. The ball milling parameters are adjusted to a rotation speed of 200 rpm and a time of 1 hour to obtain the final ball-milled material B.

[0051] Step S3: After drying material B in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C in an air atmosphere for 2 hours to obtain the catalyst, denoted as CeMn / Ru.

[0052] Comparative Example 4: Preparation of the catalyst CeMn#Ru Step S1: Weigh out 0.8865 g of manganese nitrate, 8 g of cerium nitrate, 0.0366 g of ruthenium chloride, and 5 mL of 0.1 mol / L citric acid solution, and place them together in a ball mill jar. Use a vacuum pump to evacuate to a vacuum degree of 0.1. The ball milling parameters are set as follows: ball powder mass ratio of 15:1, zirconium oxide balls 5 mm: 10 mm = 1:1, rotation speed of 600 rpm, and time of 5 h to obtain the final ball-milled material A.

[0053] Step S2: After drying material A in a vacuum oven at 100°C for 10 hours, material B is calcined in a tube furnace at 400°C under a nitrogen atmosphere for 2 hours to obtain the catalyst, denoted as CeMn#Ru.

[0054] Comparative Example 5: Preparation of CeMn & Ru catalysts In step S1, manganese and cerium are mixed at a molar ratio of 0.2:1, and ruthenium and cerium are mixed at a molar ratio of 0.01:1. 0.8865 g of manganese nitrate, 8 g of cerium nitrate, and 0.0366 g of ruthenium chloride are weighed and dissolved together. Material A is prepared by co-precipitation. Material A is dried in a vacuum oven at 100°C for 10 hours and then calcined in a muffle furnace at 400°C in air atmosphere for 2 hours to obtain the catalyst, denoted as CeMn&Ru.

[0055] Performance testing and results analysis (1) Examples 1-6 above are catalysts prepared under different conditions by the method described in this invention. The TEM images of the catalysts prepared in Examples 1 and 6 are shown below. Figure 1-6 As shown.

[0056] Depend on Figure 1 - As can be seen from Example 1-6, the catalyst products exhibit a basically similar morphology, consisting of irregularly stacked sheets, with each irregular sheet having a nano-island-like structure composed of a supported material. A detailed schematic diagram is shown below. Figure 11 As shown.

[0057] (2) The catalytic degradation performance of NOx and 1,2-dichlorobenzene prepared in Examples 1-6 and Comparative Examples 1-5 was tested using a programmed temperature fixed bed. After granulation of the prepared catalyst, 0.6 g of 40-60 mesh catalyst was weighed and mixed with 0.4 g of quartz sand of the same particle size and placed in a quartz tube. The quartz tube was then placed on a programmed temperature fixed bed. 200 ppm 1,2-dichlorobenzene, 400 ppm NO, 400 ppm NH3, and 10% O2 / N2 were introduced at a flow rate of 300 mL / min.

[0058] 1. We conducted degradation experiments on 1,2-dichlorobenzene and NOx using the catalysts prepared in Examples 1-6. The conversion efficiency of 1,2-dichlorobenzene at different temperatures is shown in Table 1. Figure 7 As shown in Table 2, the NOx conversion efficiency at different temperatures is as follows. Figure 8 As shown.

[0059] Table 1. Conversion rate (%) of 1,2-dichlorobenzene by the catalysts in Examples 1-6 at different temperatures.

[0060] Table 2. NOx conversion rate (%) of the catalysts in Examples 1-3 at different temperatures.

[0061] Depend on Figure 7As can be seen, the catalysts obtained by the methods in Examples 1-6 exhibit good low-temperature conversion of 1,2-dichlorobenzene, with a conversion rate of 90% at 250℃. Examples 1, 2, and 3 are materials obtained by loading different metals onto a cerium oxide support for oxidation, respectively. Example 4 is a catalyst obtained by replacing the cerium oxide support with a nano-titanium dioxide support. Examples 5 and 6 are catalysts obtained by changing the proportion of the loading material within a reasonable range. All of these catalysts have excellent degradation effects on 1,2-dichlorobenzene.

[0062] 2. We conducted degradation experiments on 1,2-dichlorobenzene and NOx using the catalysts obtained in Examples 1-5. The conversion efficiency of 1,2-dichlorobenzene at different temperatures is shown in Table 3. Figure 9 As shown in Table 4, the NOx conversion rate results are as follows. Figure 10 As shown.

[0063] Table 3. Conversion rate (%) of 1,2-dichlorobenzene by the catalysts in Comparative Examples 1-3 at different temperatures.

[0064] Table 4. NOx conversion rate (%) of catalysts in Comparative Examples 1-3 at different temperatures

[0065] Depend on Figure 8 and Figure 10 As can be seen from the comparison, the specific preparation process used in Example 1, including vacuum stepwise ball milling, the use of citric acid solution, inert atmosphere calcination, and stepwise ball milling steps, is crucial for obtaining a high-performance catalyst. Any change in the conditions in the comparative example resulted in a significant decrease in the catalyst's NO degradation efficiency at low temperatures, and its active temperature range narrowed, almost not overlapping with the degradation temperature range of 1,2-dichlorobenzene.

[0066] Vacuum and stepwise ball milling facilitate thorough mixing and structural optimization of materials. Ordinary ball milling or one-step ball milling may result in uneven dispersion of components, affecting the formation and distribution of active sites. Citric acid solution acts not only as a solvent but may also serve as a dispersant or structure directing agent, promoting the formation of the active phase, while deionized water cannot achieve the same effect. Inert atmosphere calcination can protect key components or structures in the catalyst precursor, while calcination in air may lead to oxidation of the active phase or structural damage. The preparation method itself also demonstrates that the ball milling-assisted process in the examples has unique advantages in constructing suitable catalyst structures and surface properties.

[0067] Therefore, the process design of the system in Example 1 contributes to the catalyst’s high NO degradation efficiency over a wide temperature range, especially at low temperatures, and its good match with the degradation temperature range of 1,2-dichlorobenzene. Any simplification or change of a single condition would significantly weaken the catalytic performance.

[0068] (3) The materials obtained in Example 1 and Comparative Examples 1-3 were tested using O2-TPD. The results are as follows: Figure 12 As shown. Compared to Comparative Examples 1-3, Example 1 exhibits the most pronounced desorption peak in the 300-600 °C range, indicating that the material in this example possesses more surface lattice adsorbed oxygen, and further demonstrating the presence of more defective oxides. The O2-TPD curve can be divided into three desorption regions: surface physico- / chemisorbed oxygen (α-O) at 100–300 °C, surface vacancy or surface lattice oxygen adsorbed oxygen (β-O) at 300–600 °C, and bulk lattice oxygen above 600 °C (γ-O). β-O plays a more crucial role, exhibiting higher mobility than lattice oxygen and participating more actively in the deep oxidation of chlorobenzene. This indicates that the material from the vacuum ball mill (Example 1) possesses a higher proportion of β-O.

[0069] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by this application.

Claims

1. An oxygen-rich vacancy nanoisland catalyst and its preparation method, characterized in that, Includes the following steps: S1. The catalyst support material and the first catalyst loading are mixed at a molar ratio of 1:(0.05-0.5), added to a ball mill jar, and ball milling beads and citric acid solution are added. After the ball mill jar is evacuated or a protective gas is introduced, it is placed on a ball mill for ball milling to obtain material A. S2. Add the second catalyst support to the ball mill jar. The molar ratio of material A to the second catalyst support is 1:(0.01-0.05). Then, evacuate the ball mill jar or introduce a protective gas and ball mill to obtain material B. S3. Dry material B in a vacuum environment and calcine it under a protective gas to obtain a defect-rich supported catalyst. The catalyst support material is one or more of the following: cerium nitrate, titanium dioxide, honeycomb framework nickel, and porous carbon materials. The first catalyst support and the second catalyst support are selected from one of manganese nitrate, cobalt nitrate, iron nitrate, copper nitrate, and ruthenium chloride, respectively, and the first catalyst support and the second catalyst support are of different types.

2. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 1, characterized in that, The concentration of the citric acid solution is 0.01-0.1 mol / L.

3. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 1, characterized in that, In step S1, the ball milling conditions are: ball milling speed 500-600 r / min, ball milling time 4-6 hours.

4. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 1, characterized in that, In step S2, the ball milling conditions are: ball milling speed 50-200 r / min, ball milling time 0.2-1 hour.

5. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the mixture of catalyst support material and first catalyst loading material in the ball mill jar to the ball milling beads is (0.5-2.5):(10-15).

6. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 5, characterized in that, The mixture of the catalyst support material and the first catalyst load occupies 1 / 3 of the volume of the ball mill jar.

7. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 1, characterized in that, The protective gas is one of nitrogen, argon, or 3% hydrogen.

8. The oxygen-rich vacancy nanoisland catalyst and its preparation method according to claim 1, characterized in that, The drying temperature described in S3 is 60-90℃, and the drying time is 10-24 hours.

9. The method according to claim 1, characterized in that: The calcination temperature in step S3 is 350-500℃, and the calcination time is 2-5 hours.

10. An oxygen-rich vacancy nanoisland catalyst prepared by the method according to any one of claims 1-9.

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