Cobalt oxide nanometer island bifunctional catalyst, preparation method and application thereof

Abstract

The application discloses a kind of cobalt oxide nano-island bifunctional catalyst and its preparation method and application, it is related to environmental catalysis and air pollution control technical field.The application includes BETA zeolite molecular sieve carrier and the cobalt oxide active component supported on the surface of carrier, and actual Co mass loading is 7.1%~10.3%.The cobalt oxide active component does not form continuous coating layer, and is distributed with multiple mutual interval local Co enrichment area on the surface of carrier;The local Co enrichment area is shown as nanometer scale particle or cluster attached to the surface of carrier in TEM image, and is shown as spatially separated Co signal enrichment area in Co element surface distribution diagram, and the structure is defined as cobalt oxide nano-island in this paper.When preparing, BETA zeolite molecular sieve is dispersed in deionized water, and is sequentially carried out cobalt precursor adsorption, alkaline precipitation, solid-liquid separation, drying and calcination.The obtained catalyst can be used for catalytic oxidation of chlorobenzene and direct catalytic decomposition of nitrous oxide respectively, and also can be used for simultaneous conversion under the condition that chlorobenzene and nitrous oxide coexist.

Description

Technical Field

[0001] This invention belongs to the field of environmental catalysis and air pollution control technology, specifically relating to a bifunctional catalyst of cobalt oxide nanoislands supported by BETA zeolite molecular sieve, its preparation method, and the application of the catalyst in the catalytic oxidation of chlorobenzene, the direct catalytic decomposition of nitrous oxide, and the simultaneous conversion of chlorobenzene and nitrous oxide under coexisting conditions. Background Technology

[0002] Industrial processes such as chemical manufacturing, pharmaceutical production, and solid waste incineration may emit chlorinated volatile organic compounds (VOCs), among which chlorobenzene exhibits high chemical stability and is difficult to treat. On the other hand, processes such as adipic acid production and nitric acid production emit nitrous oxide (N₂O). Chlorobenzene is typically treated using catalytic oxidation, while N₂O can be removed through direct catalytic decomposition. These two types of reactions have different requirements regarding the active sites and redox properties of the catalysts.

[0003] In complex industrial waste gases, chlorobenzene and N2O may coexist, accompanied by varying amounts of oxygen. Noble metal catalysts are typically expensive; conventional transition metal oxide catalysts may suffer from insufficient dispersion of active components, limited exposure of effective active sites, and unsatisfactory activity at low temperatures. Therefore, it is necessary to provide a non-noble metal catalyst with controllable structure and preparation process, enabling the same catalytic material to treat chlorobenzene and N2O separately, and also suitable for simultaneous conversion under conditions where the two coexist. Summary of the Invention

[0004] The purpose of this invention is to provide a bifunctional cobalt oxide nanoisland catalyst and its preparation method, in which the cobalt oxide active component does not form a continuous coating layer, but is distributed on the surface of a BETA zeolite molecular sieve support as multiple mutually spaced local Co enrichment regions, and the resulting catalyst can be used for catalytic oxidation of chlorobenzene, direct catalytic decomposition of N2O, and simultaneous conversion of chlorobenzene and N2O under coexisting conditions.

[0005] To address the aforementioned technical problems, this invention provides a cobalt oxide nanoisland bifunctional catalyst, comprising a BETA zeolite molecular sieve support and a cobalt oxide active component loaded on the surface of the BETA zeolite molecular sieve support; the actual Co mass loading of the catalyst is 7.1%~10.3%; the cobalt oxide active component does not form a continuous coating layer, but is distributed on the surface of the BETA zeolite molecular sieve support as multiple mutually spaced local Co enrichment regions; the local Co enrichment regions appear as nanoscale particles or clusters attached to the surface of the support in transmission electron microscopy images, and as spatially separated Co signal enrichment regions in the Co elemental distribution map.

[0006] Preferably, the method for preparing the cobalt oxide nanoisland bifunctional catalyst is characterized by comprising the following steps: (1) BETA zeolite molecular sieve was dispersed in deionized water, ultrasonically treated, and then stirred to obtain BETA zeolite molecular sieve dispersion. (2) Add cobalt precursor to the dispersion and stir to adsorb the cobalt precursor onto the surface of the BETA zeolite molecular sieve carrier to form a cobalt-containing mixture; (3) Add alkaline pH adjustment to the mixture obtained in step (2) to adjust the pH value to 8~9, and stir the reaction to allow cobalt species to be deposited on the surface of the BETA zeolite molecular sieve carrier. (4) The suspension obtained in step (3) is subjected to solid-liquid separation, and the obtained solid is dried and calcined to obtain the cobalt oxide nanoisland bifunctional catalyst.

[0007] Preferably, the cobalt precursor is cobalt nitrate hexahydrate; and the alkaline pH adjuster is ammonia.

[0008] Preferably, in step (1), the ultrasonic treatment time is 30 min; in step (2), the stirring time after adding the cobalt precursor is 10 min; in step (3), the pH value is adjusted to 8.5; in step (4), the drying time is 8~12 h; the calcination heating rate is 5℃ / min, the calcination temperature is 500℃, and the holding time is 12 h.

[0009] Preferably, the application of the cobalt oxide nanoisland bifunctional catalyst in the catalytic oxidation of chlorobenzene involves using the cobalt oxide nanoisland bifunctional catalyst for the catalytic oxidation of chlorobenzene.

[0010] Preferably, the application of the cobalt oxide nanoisland bifunctional catalyst in the direct catalytic decomposition of nitrous oxide involves using the cobalt oxide nanoisland bifunctional catalyst for the direct catalytic decomposition of nitrous oxide.

[0011] Preferably, in the catalytic oxidation of chlorobenzene, the concentration of chlorobenzene is 500~1000 ppm; in the direct catalytic decomposition of nitrous oxide, the concentration of nitrous oxide is 1000~3000 ppm; the mass-normalized gas flow rate of the cobalt oxide nanoisland bifunctional catalyst for both the catalytic oxidation of chlorobenzene and the direct catalytic decomposition of nitrous oxide is 30000~90000 mL·g⁻¹·h⁻¹, and the reaction temperature is 200~500℃.

[0012] Preferably, in the application of the cobalt oxide nanoisland bifunctional catalyst in the simultaneous conversion of chlorobenzene and nitrous oxide under coexisting conditions, a mixed gas containing chlorobenzene and nitrous oxide is simultaneously introduced into the reaction device containing the cobalt oxide nanoisland bifunctional catalyst.

[0013] Preferably, in the application of the cobalt oxide nanoisland bifunctional catalyst in the simultaneous conversion of chlorobenzene and nitrous oxide under coexisting conditions, the concentration of nitrous oxide in the mixed gas is 1000~3000 ppm, the concentration of chlorobenzene is 500~1000 ppm, the volume fraction of oxygen is 0%~20%, and the remaining gas is nitrogen; the mass-normalized gas flow rate of the cobalt oxide nanoisland bifunctional catalyst is 30000~90000 mL·g⁻¹·h⁻¹, and the reaction temperature is 200~500℃.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: (1) "Cobalt oxide nanoislands" are nanoscale particles or clusters distributed on the surface of BETA molecular sieves that are spaced apart from each other and do not form a continuous coating layer, while the local enrichment of Co element is only used as an auxiliary characterization basis. (2) Through a preparation process combining cobalt precursor adsorption and alkaline precipitation, the cobalt oxide active component does not form a continuous coating layer, but is distributed on the surface of the BETA zeolite molecular sieve support as multiple mutually spaced local Co enrichment regions; combined with the actual Co mass loading of 7.1%~10.3%, the nanoscale particles or clusters in the TEM image, and the spatial separation enrichment characteristics in the Co element surface distribution map, the cobalt oxide nanoislands are structurally defined in a detectable manner. (3) The obtained catalyst has both applications of chlorobenzene catalytic oxidation and direct N2O catalytic decomposition. Under the test conditions of Example 1, the chlorobenzene conversion rate T 50 and T 90 T values ​​for N2O conversion at 255℃ and 310℃ respectively 50 and T 90 The temperatures were 344℃ and 418℃, respectively.

[0015] (4) Compared with Comparative Example 1 prepared by the impregnation-evaporation method, Example 1 showed a lower T value in both types of reactions. 50 and T 90 This indicates that the preparation process is beneficial for improving catalytic activity. Combined with... Figure 6 The ICP results shown indicate that the actual Co mass loading of Comparative Example 1 was 8.5%, which falls within the range of 7.1% to 10.3% for Examples 1 to 3. This suggests that the performance difference between the two types of catalysts cannot be simply attributed to the difference in Co loading.

[0016] (5) The catalyst can also be used for the simultaneous conversion of chlorobenzene and N2O in a mixed gas. Under four oxygen volume fractions of 0%, 5%, 10%, and 20%, the catalyst can simultaneously convert both pollutants, and the oxygen volume fraction has different effects on the conversion performance of chlorobenzene and N2O. Furthermore, in the N2O switching experiment at 450℃ under anaerobic conditions, after introducing 2000 ppm N2O, the conversion rate of approximately 500 ppm chlorobenzene gradually increased from close to 0 to approximately 35%, indicating that the introduction of N2O can promote the conversion of chlorobenzene, demonstrating the synergistic promoting characteristics of the two pollutants on the catalyst. Attached Figure Description

[0017] Figure 1 The curves showing the chlorobenzene conversion rate as a function of temperature for the catalysts obtained in Examples 1-3 and Comparative Examples 1-2 are shown. Figure 2 The curves showing the N2O conversion rate as a function of temperature for the catalysts obtained in Examples 1-3 and Comparative Examples 1-2 are shown. Figure 3 The X-ray diffraction (XRD) patterns of the catalysts obtained in Examples 1-3 and Comparative Examples 1-2 are shown below. Figure 4 The nitrogen adsorption isotherm and pore size distribution curves are shown for the catalyst obtained in Example 1 and Comparative Example 2. Figure 5 The nitrogen desorption isotherm and pore size distribution curves of the catalyst obtained in Example 1 and Comparative Example 2 are shown. Figure 6 The actual cobalt loading test results are for samples prepared under pH conditions of 7.0, 8.0, 8.5 and 9.0, and for Comparative Example 1 (IMP) prepared by the impregnation method. Figure 7 The graph shows the performance of the catalyst obtained in Example 1 in the simultaneous conversion of chlorobenzene at different oxygen volume fractions. Figure 8 The graph shows the performance of the catalyst obtained in Example 1 in simultaneously converting N2O at different oxygen volume fractions. Figure 9 The images show scanning electron microscope (SEM) images of the catalysts obtained in Example 1 and Comparative Example 1. Figure 10 Transmission electron microscopy (TEM) images and surface distribution images of Co and Si elements obtained in Example 1 and Comparative Example 1; Figure 11 The curve showing the change of Zeta potential of the catalyst obtained in Example 1 as a function of pH value; Figure 12 The zero charge point (PZC) curve of the catalyst obtained in Example 1 was measured using the pH drift method; Figure 13The curves showing the conversion rates of chlorobenzene and N2O over time during the N2O switching experiment at 450°C under anaerobic conditions in Example 1 are shown. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. These embodiments are intended to facilitate a better understanding of the invention, but are not intended to limit the invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods. All reagents not specifically mentioned are of analytical grade, and the water used is deionized water.

[0019] Example 1 The specific steps for preparing the cobalt oxide nano-island bifunctional catalyst in this embodiment are as follows: (1) Add 1.0g of BETA zeolite molecular sieve to 100mL of deionized water, ultrasonically disperse for 30min and continue stirring to make the BETA zeolite molecular sieve uniformly dispersed. (2) Weigh 0.5611 g of cobalt nitrate hexahydrate and add it to the dispersion obtained in step (1), and stir for 10 min; (3) Add ammonia water slowly under stirring conditions to adjust the pH of the system to 8.5; (4) The suspension obtained in step (3) was vacuum filtered, and the resulting solid was dried at room temperature for 12 hours. Then it was placed in a muffle furnace and heated to 500°C at a heating rate of 5°C / min and kept at that temperature for 12 hours to obtain the catalyst of Example 1.

[0020] Example 2 Except for adjusting the pH of the system to 8.0 in step (3), the other preparation conditions are the same as in Example 1.

[0021] Example 3 Except for adjusting the pH of the system to 9.0 in step (3), the other preparation conditions are the same as in Example 1.

[0022] Comparative Example 1 CoOx / BETA catalysts were prepared using an impregnation-evaporation method. 1.0 g of BETA zeolite molecular sieve was added to deionized water, ultrasonically dispersed, and then 0.5611 g of cobalt nitrate hexahydrate was added. The mixture was stirred at room temperature for 2 h; subsequently, the water was evaporated in an oven at 80 °C, and the mixture was calcined at 500 °C for 12 h to obtain the catalyst of Comparative Example 1.

[0023] Comparative Example 2 BETA zeolite molecular sieve was used as comparative example 2.

[0024] Performance testing The samples obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to chlorobenzene catalytic oxidation and N2O direct catalytic decomposition tests, and the catalyst obtained in Example 1 was subjected to simultaneous conversion tests under the condition of coexistence of chlorobenzene and N2O.

[0025] Chlorobenzene catalytic oxidation test: 0.1g of catalyst with a particle size of 40-60 mesh was used. The concentration of chlorobenzene in the reaction gas was 500ppm, the volume fraction of oxygen was 20%, and the remaining gas was nitrogen. The normalized gas flow rate of the catalyst was 60000mL·g⁻¹·h⁻¹. The concentration of chlorobenzene at the inlet and outlet of the reactor was monitored by online gas chromatography, and the chlorobenzene conversion rate was calculated accordingly.

[0026] Direct catalytic decomposition test of N2O: Take 0.1g of catalyst with a particle size of 40~60 mesh, the N2O concentration in the reaction gas is 2000ppm, nitrogen is used as the balance gas, and the catalyst mass normalized gas flow rate is 60000mL·g⁻¹·h⁻¹; calculate the N2O conversion rate based on the N2O concentration at the inlet and outlet of the reactor.

[0027] Simultaneous conversion test of chlorobenzene and N2O in coexistence: 0.1 g of the catalyst from Example 1 with a particle size of 40-60 mesh was placed in the same reaction apparatus as in the single-treatment test, and a mixed gas consisting of chlorobenzene, N2O, and oxygen was simultaneously introduced. The concentration of chlorobenzene was 500 ppm, the concentration of N2O was 2000 ppm, and the oxygen volume fractions were set to 0%, 5%, 10%, and 20%, respectively. The remaining gas was nitrogen. The catalyst mass-normalized gas flow rate was 60000 mL·g⁻¹·h⁻¹, and other test conditions were the same as in the single-treatment test. The concentrations of chlorobenzene and N2O at the reactor inlet and outlet were monitored to evaluate the simultaneous conversion performance of the two pollutants under different oxygen volume fractions. The test results are shown in […]. Figure 7 and Figure 8 The above specific conditions are preferred test conditions; in application, the concentration of chlorobenzene can be 500~1000 ppm, the concentration of N2O can be 1000~3000 ppm, the volume fraction of oxygen can be 0%~20%, the normalized gas flow rate of the catalyst can be 30000~90000 mL·g⁻¹·h⁻¹, and the reaction temperature can be 200~500℃.

[0028] N2O switching experiment under anaerobic conditions: The catalyst from Example 1 was used and tested at a constant temperature of 450℃. The concentration of chlorobenzene in the reaction gas was approximately 500 ppm, the oxygen volume fraction was 0%, and the remaining gas was nitrogen. No N2O was introduced from 0 to 40 min; at 40 min, N2O was turned on to make the N2O concentration in the reaction gas 2000 ppm, and the changes in the conversion rates of chlorobenzene and N2O over time were continuously recorded. The test results are shown in […]. Figure 13 .

[0029] Depend on Figure 13It can be seen that within 0–40 min without N2O introduction, the chlorobenzene conversion rate is close to 0; after N2O is introduced, the N2O conversion rate gradually increases to about 95% over time, while the chlorobenzene conversion rate gradually increases from close to 0 to about 35%. Under conditions where no external oxygen is added and other atmospheric conditions remain constant, the chlorobenzene conversion rate significantly increases with the introduction of N2O, indicating that the introduction of N2O has a synergistic promoting effect on chlorobenzene conversion and supports the synergistic conversion of chlorobenzene and N2O on the catalyst.

[0030] T 50 and T 90 These represent the reaction temperatures corresponding to when the conversion rate of the target pollutant reaches 50% and 90%, respectively.

[0031] Table 1 Physical properties of each catalyst

[0032] Table 2. Catalytic oxidation performance of chlorobenzene by various catalysts

[0033] Table 3. Direct catalytic decomposition performance of N2O by various catalysts

[0034] As shown in Tables 2 and 3, the T values ​​in Example 1 for catalytic oxidation of chlorobenzene and direct catalytic decomposition of N2O are... 50 T 90 All were lower than those of Examples 2, 3, and Comparative Example 1. The above results indicate that, under the preparation and testing conditions given in this application, the catalyst obtained by adjusting the pH of the system to 8.5 exhibited good catalytic activity for both types of reactions. Figure 6 It can be seen that the actual Co mass loading of Comparative Example 1 (IMP) is 8.5%, which is higher than that of Example 2 (7.1%), but its N2O conversion rate corresponds to T 50 and T 90 The temperatures were 16°C and 20°C higher than those in Example 2, respectively. Meanwhile, the Co loading in Comparative Example 1 was in the range of 7.1% to 10.3% as in Examples 1-3, yet it did not exhibit catalytic performance that simply correlated with the loading. Therefore, the performance difference between the impregnation catalyst and the cobalt oxide nanoisland catalyst cannot be simply attributed to the difference in Co loading. The discrete distribution of cobalt oxide on the BETA support surface and the structural characteristics of not forming a continuous coating layer are important factors affecting catalytic performance.

[0035] Structural and morphological characterization: by Figure 6It can be seen that the actual Co mass loadings of the samples prepared under pH conditions of 7.0, 8.0, 8.5, and 9.0, as well as the impregnation method comparative example 1 (IMP), were 5.2%, 7.1%, 10.3%, 9.7%, and 8.5%, respectively. Among them, the actual Co mass loadings of Examples 1-3 remained between 7.1% and 10.3%, while the actual Co mass loading of Comparative Example 1 was 8.5%, falling within the loading range of Examples 1-3. The catalysts obtained in Examples 1 and Comparative Example 1 were characterized using scanning electron microscopy, transmission electron microscopy, and elemental surface distribution analysis. The results are shown in [Figure number missing]. Figure 9 and Figure 10 TEM images reveal nanoscale particles or clusters attached to the surface of the BETA zeolite molecular sieve support. The Co and Si elemental distribution maps show that the Co signal exhibits multiple interspersed localized enrichment regions on the support surface, with weaker Co signal regions between adjacent enriched areas, failing to form a continuous Co signal layer covering the entire support surface. Therefore, this paper defines the cobalt oxide active component region, characterized by "not forming a continuous coating layer, consisting of multiple interspersed localized Co enrichment regions, and appearing as nanoscale particles or clusters in TEM images," as cobalt oxide nanoislands. The aforementioned actual Co mass loading, TEM morphology, and Co elemental distribution results collectively constitute the characterization basis for the cobalt oxide nanoisland structure.

[0036] Surface electrical characterization: The catalyst obtained in Example 1 was subjected to zeta potential testing and pH drift zero-charge point testing. The results are shown in the figure below. Figure 11 and Figure 12 .Depend on Figure 11 It can be seen that the zeta potential changes from positive to negative as pH increases, and the electrokinetic isoelectric point (IEP) is approximately 4.51; Figure 12 It can be seen that the point of zero charge (PZC) corresponding to the intersection of the initial pH and equilibrium pH curves with respect to the y=x line is approximately 3.32. IEP reflects the pH when the kinetic potential of the particles in a specific dispersion system is zero, while PZC reflects the pH when the net surface charge is zero. The two measurements are based on different principles, and their values ​​may differ. The above results indicate that the surface charge state of the obtained catalyst changes with the pH of the system, which can provide a reference for analyzing its surface acid-base properties and interfacial interactions. Combined with the preparation process described, adjusting the system pH is beneficial for changing the charge state at the solid-liquid interface, thereby promoting the adsorption and fixation of cobalt species on the surface of the BETA zeolite molecular sieve support under electrostatic interaction.

[0037] Obviously, the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, these obvious variations or modifications derived from the spirit of the present invention are still within the scope of protection of the present invention.

Claims

1. A bifunctional catalyst for cobalt oxide nanoislands, characterized in that, The catalyst includes a BETA zeolite molecular sieve support and a cobalt oxide active component loaded on the surface of the BETA zeolite molecular sieve support. The actual Co mass loading of the catalyst is 7.1% to 10.3%. The cobalt oxide active component is attached to the surface of the BETA zeolite molecular sieve support as multiple separate particles or clusters. Observation by transmission electron microscopy shows that the lateral projection size of the particles or clusters is at the nanoscale and less than 100 nm, and there are identifiable carrier surface intervals between adjacent particles or clusters. In the Co and Si elemental distribution map, the Co signal shows multiple spatially separated local enrichment regions. There are carrier exposed areas with weak Co signals and identifiable Si signals between adjacent Co enrichment regions, and no continuous Co signal layer covering the surface of the support is formed.

2. A method for preparing the cobalt oxide nano-island bifunctional catalyst as described in claim 1, characterized in that, Includes the following steps: BETA zeolite molecular sieve was dispersed in deionized water, ultrasonicated, and then stirred to obtain BETA zeolite molecular sieve dispersion. Add cobalt precursor to the dispersion and stir to allow the cobalt precursor to adsorb onto the surface of the BETA zeolite molecular sieve support, forming a cobalt-containing mixture. Add alkaline pH adjustment to the mixture obtained in step (2) to adjust the pH value to 8~9, and stir the reaction to allow cobalt species to be deposited on the surface of the BETA zeolite molecular sieve carrier. (4) The suspension obtained in step (3) is subjected to solid-liquid separation, and the obtained solid is dried and calcined to obtain the cobalt oxide nanoisland bifunctional catalyst.

3. The method for preparing the cobalt oxide nano-island bifunctional catalyst according to claim 2, characterized in that, The cobalt precursor is cobalt nitrate hexahydrate; the alkaline pH adjuster is ammonia.

4. The method for preparing the cobalt oxide nano-island bifunctional catalyst according to claim 2, characterized in that, In step (1) above, the ultrasonic treatment time is 30 min; in step (2) above, the stirring time after adding the cobalt precursor is 10 min; in step (3) above, the pH value is adjusted to 8.5; in step (4) above, the drying time is 8~12 h; the calcination heating rate is 5℃ / min, the calcination temperature is 500℃, and the holding time is 12 h.

5. A bifunctional catalyst for cobalt oxide nanoislands, characterized in that, It is prepared by the preparation method according to any one of claims 2 to 4.

6. The application of the cobalt oxide nano-island bifunctional catalyst according to claim 5 in the catalytic oxidation of chlorobenzene, characterized in that, Cobalt oxide nanoisland bifunctional catalysts were used for the catalytic oxidation of chlorobenzene.

7. The application of the cobalt oxide nano-island bifunctional catalyst according to claim 5 in the direct catalytic decomposition of nitrous oxide, characterized in that, Cobalt oxide nanoisland bifunctional catalysts were used for the direct catalytic decomposition of nitrous oxide.

8. The application of the cobalt oxide nanoisland bifunctional catalyst according to claim 6 or 7 in the catalytic oxidation of chlorobenzene, characterized in that, In the catalytic oxidation of chlorobenzene, the concentration of chlorobenzene is 500~1000 ppm; in the direct catalytic decomposition of nitrous oxide, the concentration of nitrous oxide is 1000~3000 ppm; the mass-normalized gas flow rate of the cobalt oxide nanoisland bifunctional catalyst for both the catalytic oxidation of chlorobenzene and the direct catalytic decomposition of nitrous oxide is 30000~90000 mL·g⁻¹·h⁻¹, and the reaction temperature is 200~500℃.

9. The application of the cobalt oxide nano-island bifunctional catalyst according to claim 5 in the simultaneous conversion of chlorobenzene and nitrous oxide under coexisting conditions, characterized in that, A mixture of chlorobenzene and nitrous oxide is simultaneously introduced into a reaction apparatus containing a cobalt oxide nanoisland bifunctional catalyst.

10. The application of the cobalt oxide nano-island bifunctional catalyst according to claim 9 in the simultaneous conversion of chlorobenzene and nitrous oxide under coexisting conditions, characterized in that, The mixed gas contains nitrous oxide at a concentration of 1000-3000 ppm, chlorobenzene at a concentration of 500-1000 ppm, oxygen at a volume fraction of 0%-20%, and the remainder is nitrogen; the mass-normalized gas flow rate of the cobalt oxide nanoisland bifunctional catalyst is 30000-90000 mL·g⁻¹·h⁻¹, and the reaction temperature is 200-500℃.

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