A nanofiber catalyst for SO2 to sulfur production, its preparation method and application
The metal composite oxide catalyst prepared by the template method solves the problem of low efficiency in the resource utilization of sulfur dioxide in the existing technology, and achieves the effect of efficient and low-cost conversion of sulfur dioxide into sulfur, which is suitable for the resource utilization of industrial flue gas.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING TECH UNIV
- Filing Date
- 2024-04-08
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies struggle to efficiently utilize sulfur dioxide from industrial flue gas, particularly in the catalyst preparation process, where high costs, uneven adhesion of active components, and weak binding forces result in low efficiency in the conversion of sulfur dioxide into sulfur.
A template method was used to prepare a metal composite oxide catalyst. Using carbon fiber hollow tubes and carbon nanospheres as templates, a high-performance SO2 to sulfur nanofiber catalyst was prepared through high-temperature calcination, hydrothermal method and microwave calcination. The active components are mainly manganese oxide, cerium oxide and cobalt oxide, which improves the specific surface area of the catalyst and the adhesion of the active components.
It achieves efficient catalytic reduction of sulfur dioxide to sulfur at a lower temperature, with readily available raw materials, high catalyst activity, and suitability for large-scale production. Furthermore, the active components are uniformly loaded and have strong binding force.
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Figure CN118287094B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a nanofiber catalyst for SO2 to sulfur production, its preparation method, and its application, belonging to the field of flue gas resource utilization and treatment. Background Technology
[0002] With the advancement of industrialization and urbanization, environmental issues have received increasing attention, with industrial flue gas emissions being a significant source of pollution. Flue gas emitted during industrial production contains a large number of pollutants, among which sulfur dioxide emissions pose a particularly serious threat to the environment and human health. When sulfur dioxide is released into the atmosphere, it contributes to smog. Sulfur dioxide reacts with oxygen and water vapor in the atmosphere to form sulfuric acid, leading to acidic deposition that affects ecological balance and crop yields. Furthermore, sulfur dioxide is an irritant gas; long-term exposure to high concentrations can cause respiratory diseases. Therefore, controlling sulfur dioxide emissions from industry is a crucial measure for protecting the environment and safeguarding human health.
[0003] Although sulfur dioxide in flue gas is a pollutant, it is also a potential resource. Through resource utilization, waste sulfur dioxide can be converted into valuable chemicals, achieving the goal of transforming waste into valuable resources and helping to reduce air pollutant emissions and protect the environment. Resource utilization of sulfur dioxide can produce chemical products such as sulfur, sulfuric acid, hydrogen sulfide, and elemental sulfur, meeting the needs of industrial production. Among the many methods for resource utilization of sulfur dioxide flue gas, catalysts for reducing sulfur dioxide to sulfur using carbon monoxide have advantages such as high reaction rate, good selectivity, strong stability, and excellent environmental performance. Therefore, the development of highly efficient new catalytic materials has attracted much attention from researchers and is of great significance for the resource utilization of sulfur dioxide flue gas. Summary of the Invention
[0004] The purpose of this invention is to promote the resource utilization of sulfur dioxide flue gas. The catalyst of this invention is a metal composite oxide catalyst prepared by a template method. The template in the preparation process is a mixture of carbon fiber hollow tubes and carbon nanospheres, and the final catalyst material is a metal composite oxide. In the catalyst design, using wood to prepare carbon fiber hollow tubes can reduce the preparation cost and improve the feasibility of large-scale fiber preparation. During the wood preparation process, high-concentration hot alkaline and hot acid solutions are used to treat hemicellulose, which is easily hydrolyzed and degraded. This removes non-fiber impurities from the wood and improves the hollowness and permeability of the fibers, which is beneficial for the subsequent loading of active components. High-speed ball milling in a ball mill can break the wood fibers into short-range ordered micro-nano structures. Then, the wood fibers are carbonized in a high-temperature nitrogen atmosphere to form carbon nanofiber hollow tubes, which significantly increases the specific surface area of the template material and provides more sites for the attachment of active components. Grapes are hydrothermally converted into carbon nanospheres and loaded onto carbon nanofibers to prepare a catalyst template. The loaded carbon nanospheres further increase the specific surface area of the template, and under hydrothermal conditions, functional groups such as hydroxyl groups are introduced into the material surface, which is beneficial for the loading of active components. Furthermore, microwave calcination can remove glucose and other impurities that were not completely converted during hydrothermal treatment, and can also further improve the bonding strength between the hollow tubes of carbon nanofibers and carbon nanospheres, preventing the nanospheres and nanofibers from not sticking together during the later loading of the active component. Finally, the active component is loaded onto the prepared template by hydrothermal treatment. Under high temperature and high pressure conditions, the adhesion performance of the active component is better, and its adhesion amount is also greater. Therefore, after the template material is removed by high-temperature calcination, the active component per unit mass of the catalyst is maximized, and a high-performance catalytic material is finally obtained.
[0005] This invention can be achieved through the following technical solution: This invention discloses a method for preparing a nanofiber catalyst for SO2 to sulfur production. The catalyst uses a mixture of carbon nanospheres and hollow carbon nanofiber tubes as a template, manganese oxide and cerium oxide as active components, and cobalt oxide as a co-catalyst. The catalyst preparation process first involves carbonizing wood into hollow carbon nanofiber tubes, then loading carbon nanospheres onto the hollow carbon nanofiber tubes to form a template, followed by a hydrothermal method to achieve the bonding between the template and the active components, and finally removing the template by high-temperature calcination to obtain the pure active component catalyst.
[0006] The specific technical solution is as follows:
[0007] A method for preparing a nanofiber catalyst for SO2 to sulfur production, the method comprising the following steps:
[0008] (1) Preparation of carbon nanofiber hollow tubes
[0009] The wood was immersed in hot alkaline solution and hot acid solution in turn. After the acid immersion was completed, it was rinsed, ground and sieved. Then it was transferred to a high-temperature carbonization furnace and calcined with nitrogen gas to finally obtain carbon nanofiber hollow tubes.
[0010] (2) Preparation of catalyst template
[0011] The carbon nanofiber hollow tubes prepared in step (1) were added to a glucose aqueous solution and subjected to a hydrothermal reaction. After the hydrothermal reaction was completed, microwave calcination was performed to finally obtain the catalyst template.
[0012] Loading of active components and removal of template
[0013] Manganese nitrate, cerium nitrate, and cobalt nitrate were dissolved in deionized water to form an active component precursor solution. The template material obtained in step (2) was then added to the precursor solution and subjected to a hydrothermal reaction. After the reaction was completed, the solution was transferred to a muffle furnace for high-temperature calcination to remove the template and finally obtain the catalyst.
[0014] In the above preparation method: the wood mentioned in step (1) is a cylindrical apricot or peach wood with a diameter of 4-6 mm and a height of 20-25 mm.
[0015] In the above preparation method: the hot alkaline solution mentioned in step (1) is a 10-15 mol / L NaOH solution at 60℃-70℃, and the immersion time is 1h-2h.
[0016] In the above preparation method: the hot acid solution mentioned in step (1) is a 7-9 mol / L H2SO4 solution at 50℃-60℃, and the immersion time is 3h-5h.
[0017] In the above preparation method: the sieve used in step (1) is 150-250 mesh.
[0018] In the above preparation method: the calcination temperature in step (1) is 600℃~800℃, the calcination time is 5~6h, and the nitrogen gas introduction rate is 20~40mL / min.
[0019] In the above preparation method: the mass ratio of the carbon nanofiber hollow tube to glucose in step (2) is (5-7):(2-3);
[0020] Preferably, the temperature of the hydrothermal reaction in step (2) is 160℃~190℃, and the time of the hydrothermal reaction is 12h~16h;
[0021] Preferably, the microwave roasting furnace described in step (2) has a microwave power of 1 to 5 kW, a microwave roasting temperature of 800°C to 900°C, a microwave roasting time of 15 to 30 min, and is in a nitrogen atmosphere of 30 to 60 ml / min.
[0022] In the above preparation method: the mass ratio of manganese nitrate, cerium nitrate, cobalt nitrate and deionized water in step (3) is (0.5-2):(1-4):(0.5-3):(3-9);
[0023] The mass ratio of the precursor solution to the template obtained in step (2) is (8-12):(1-5);
[0024] The hydrothermal reaction temperature in step (3) is 200℃~220℃, and the hydrothermal reaction time is 3h~5h;
[0025] The high-temperature roasting temperature in the muffle furnace mentioned in step (3) is 500℃~600℃, and the high-temperature roasting time is 8h~10h.
[0026] A nanofiber catalyst for the production of sulfur from SO2, which is prepared by the method described above.
[0027] In the technical solution of this invention, the catalyst is used in the catalytic reduction of sulfur dioxide by carbon monoxide to sulfur.
[0028] Beneficial effects:
[0029] (1) The catalyst can catalytically reduce SO2 to sulfur at a lower temperature, and the raw materials are cheap and readily available, which is conducive to large-scale engineering preparation.
[0030] (2) During the hydrothermal reaction of glucose with carbon nanofiber hollow tubes, glucose undergoes oxidation and cleavage reactions, generating hydroxyl (-OH) and carboxyl (-COOH) functional groups containing hydroxyl groups. These functional groups increase the hydrophilicity of the carbon nanotube surface, which can effectively improve the dispersibility of carbon nanotubes and make them more stable in the solution. This promotes the loading of active components under hydrothermal conditions in subsequent steps, making the loading of active components more uniform and the loading binding force stronger.
[0031] (3) Microwave radiation generates an electromagnetic field, which excites the vibration and rotation of molecules inside carbon materials, increasing the intermolecular distance. This facilitates the rearrangement of atoms or molecules on the surface, forming new surface defects and promoting the placement of carbon nanotubes. At the same time, microwave calcination can also cause local temperature gradient changes in carbon materials, leading to local pressure changes and applying force to the surface structure of the material, thereby strengthening the bond between hollow tubes and carbon nanospheres in carbon nanofibers. Attached Figure Description
[0032] Figure 1 The graph shows the catalytic conversion efficiency of SO2 by the catalysts prepared in Examples 1-3 and Comparative Examples 1-3.
[0033] Figure 2 SEM image of the catalyst prepared in Example 1 Detailed Implementation
[0034] The following examples further illustrate the preparation method of the SO2-to-sulfur nanofiber catalyst according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.
[0035] Unless otherwise specified, the experimental methods in the following embodiments are conventional methods in the art, and the experimental apparatus and experimental materials are commercially available unless otherwise specified.
[0036] Example 1
[0037] (1) Preparation of carbon nanofiber hollow tubes
[0038] Twenty cylindrical apricot wood pieces, each 4 mm in diameter and 20 mm in height, were immersed in 500 ml of a 10 mol / L NaOH solution and kept at a constant temperature of 60°C for 1 hour. The material was then rinsed with deionized water until the rinse water was neutral. Next, the material was immersed in 500 ml of a 7 mol / L H₂SO₄ solution and kept at a constant temperature of 50°C for 3 hours. After rinsing, the material was rinsed again with deionized water until the rinse water was neutral. After rinsing, the material was fed into a high-speed planetary ball mill and ground for 10 minutes at a rotation speed of 1000 rpm and a revolution speed of 200 rpm. The material was then discharged and passed through a 200-mesh sieve. The dried material was then transferred to a high-temperature carbonization furnace and carbonized at 600°C for 5 hours under nitrogen conditions at a flow rate of 20 ml / min to obtain carbon nanofiber hollow tubes.
[0039] (2) Preparation of catalyst template
[0040] Weigh 20g of glucose and add 150g of deionized water. Stir and dissolve evenly. Then add 50g of carbon nanofiber hollow tube prepared in step (1) and stir evenly again. Transfer to a hydrothermal reactor and hydrothermally react at 160℃ for 12h. After hydrothermal reaction, transfer the material to a microwave calcination furnace and calcine at 1kW microwave power and 800℃ for 15min under a nitrogen atmosphere of 40ml / min to obtain the catalyst template.
[0041] (3) Loading of active components and removal of template
[0042] 10g of manganese nitrate, 20g of cerium nitrate and 10g of cobalt nitrate were dissolved in 70g of deionized water to form an active component precursor solution. Then, 22g of the template material obtained in step (2) was added to the precursor solution and transferred to a hydrothermal reactor for hydrothermal reaction at 200℃ for 3h. After the reaction was completed, the material was transferred to a muffle furnace and calcined at 500℃ for 8h to remove the template component and obtain the catalyst.
[0043] (4) Catalyst activity test
[0044] The sulfide catalyst obtained by the above method was applied to the reaction of CO catalytic reduction of SO2 to produce sulfur. The amount of catalyst was 1 mL, the total gas flow rate was 500 mL / min, which contained 0.25% SO2, 0.5% CO, and the remainder was N2. The reaction temperature was 250-400℃. A heating belt was set at the tail end of the quartz tube and the temperature was kept constant at 120℃. The sulfur vapor passed through the heating belt with other tail gases and entered the cold hydrazine to become solid, and the sulfur was collected.
[0045] Example 2
[0046] (1) Preparation of carbon nanofiber hollow tubes
[0047] Twenty cylindrical pieces of peach wood, each 5 mm in diameter and 22 mm in height, were immersed in 500 ml of a 12 mol / L NaOH solution and kept at a constant temperature of 65°C for 1.5 h. The material was then rinsed with deionized water until the rinse water was neutral. Next, the material was immersed in 500 ml of an 8 mol / L H₂SO₄ solution and kept at a constant temperature of 55°C for 4 h. After rinsing, the material was rinsed again with deionized water until the rinse water was neutral. After rinsing, the material was fed into a high-speed planetary ball mill and ground for 12 min at a rotation speed of 1100 rpm and a revolution speed of 250 rpm. The material was then discharged and passed through a 200-mesh sieve. The dried material was then transferred to a high-temperature carbonization furnace and carbonized at 700°C for 5.5 h under nitrogen conditions at a flow rate of 30 ml / min to obtain carbon nanofiber hollow tubes.
[0048] (2) Preparation of catalyst template
[0049] Weigh 25g of glucose and add 160g of deionized water and stir to dissolve evenly. Then add 60g of carbon nanofiber hollow tube prepared in step (1) and stir evenly again. Transfer to a hydrothermal reactor and hydrothermally react at 170℃ for 14h. After hydrothermal reaction, transfer the material to a microwave calcination furnace and calcinate at 850℃ for 20min under a nitrogen atmosphere of 50ml / min to obtain a catalyst template.
[0050] (3) Loading of active components and removal of template
[0051] 10g of manganese nitrate, 20g of cerium nitrate and 10g of cobalt nitrate were dissolved in 60g of deionized water to form an active component precursor solution. Then, 30g of the template material obtained in step (2) was added to the precursor solution and transferred to a hydrothermal reactor for hydrothermal reaction at 210℃ for 4h. After the reaction was completed, the material was transferred to a muffle furnace and calcined at 550℃ for 9h to remove the template component and obtain the catalyst.
[0052] (4) Catalyst activity test
[0053] The sulfide catalyst obtained by the above method was applied to the reaction of CO catalytic reduction of SO2 to produce sulfur. The amount of catalyst was 1 mL, the total gas flow rate was 500 mL / min, which contained 0.25% SO2, 0.5% CO, and the remainder was N2. The reaction temperature was 250-400℃. A heating belt was set at the tail end of the quartz tube and the temperature was kept constant at 120℃. The sulfur vapor passed through the heating belt with other tail gases and entered the cold hydrazine to become solid, and the sulfur was collected.
[0054] Example 3
[0055] (1) Preparation of carbon nanofiber hollow tubes
[0056] Twenty cylindrical apricot wood pieces, each 6 mm in diameter and 25 mm in height, were immersed in 500 ml of a 15 mol / L NaOH solution and kept at a constant temperature of 70°C for 2 hours. After immersion, the material was rinsed with deionized water until the rinse water was neutral. The material was then immersed in 500 ml of a 9 mol / L H₂SO₄ solution and kept at a constant temperature of 60°C for 5 hours. After rinsing, the material was rinsed again with deionized water until the rinse water was neutral. After rinsing, the material was fed into a high-speed planetary ball mill and ground for 15 minutes at a rotation speed of 1200 rpm and a revolution speed of 300 rpm. The material was then discharged and passed through a 200-mesh sieve. The dried material was then transferred to a high-temperature carbonization furnace and carbonized at 800°C for 6 hours under nitrogen conditions at a flow rate of 40 ml / min, ultimately yielding carbon nanofiber hollow tubes.
[0057] (2) Preparation of catalyst template
[0058] Weigh 30g of glucose and add 150g of deionized water. Stir and dissolve evenly. Then add 70g of carbon nanofiber hollow tube prepared in step (1) and stir evenly again. Transfer to a hydrothermal reactor and hydrothermally react at 190℃ for 16h. After hydrothermal reaction, transfer the material to a microwave calcination furnace and calcine at 5kW microwave power and 900℃ for 30min under a nitrogen atmosphere of 60ml / min to obtain the catalyst template.
[0059] (3) Loading of active components and removal of template
[0060] 10g of manganese nitrate, 20g of cerium nitrate and 10g of cobalt nitrate were dissolved in 50g of deionized water to form an active component precursor solution. Then, 35g of the template material obtained in step (2) was added to the precursor solution and transferred to a hydrothermal reactor for hydrothermal reaction at 220℃ for 5h. After the reaction was completed, the material was transferred to a muffle furnace and calcined at 600℃ for 10h to remove the template component and obtain the catalyst.
[0061] (4) Catalyst activity test
[0062] The sulfide catalyst obtained by the above method was applied to the reaction of CO catalytic reduction of SO2 to produce sulfur. The amount of catalyst was 1 mL, the total gas flow rate was 500 mL / min, which contained 0.25% SO2, 0.5% CO, and the remainder was N2. The reaction temperature was 250-400℃. A heating belt was set at the tail end of the quartz tube and the temperature was kept constant at 120℃. The sulfur vapor passed through the heating belt with other tail gases and entered the cold hydrazine to become solid, and the sulfur was collected.
[0063] Comparative Example 1
[0064] (1) Catalyst preparation: Except for the alkaline leaching and acid leaching in step (1) which are carried out at room temperature without heating, the other conditions are the same as in Example 1.
[0065] (2) Activity Test: The catalyst dosage was 1 mL, the total gas flow rate was 500 mL / min, containing 0.25% SO2, 0.5% CO, and the remainder N2. The reaction temperature was 250–400 °C. A heating belt was installed at the tail end of the quartz tube, and the temperature was kept constant at 120 °C. Sulfur vapor, along with other tail gases, passed through the heating belt and entered the cold hydrazine, where it solidified and was collected. The catalyst's efficiency in converting SO2 to sulfur is evaluated in [reference needed]. Figure 1 .
[0066] (3) Comparative effect: Without heating and alkaline leaching, the catalyst showed a maximum SO2 conversion rate of only 57.3% in the catalyst activity test within the temperature range of 250-400℃. This was mainly because the hemicellulose in the wood could not be effectively decomposed and some other impurities in the wood were difficult to separate or dissolve, resulting in insufficient separation of wood fibers. In the subsequent carbonization process, it was also difficult to form hollow carbon nanofiber tubes, resulting in insufficient specific surface area of the catalyst template and insufficient attachment sites for active components, leading to a decrease in catalyst activity.
[0067] Comparative Example 2
[0068] (1) Catalyst preparation: Except for step (2), which does not involve microwave calcination, the catalyst is prepared by calcining the material in a nitrogen atmosphere using a conventional tube furnace. Other conditions are the same as in Example 2.
[0069] (2) Activity Test: The catalyst dosage was 1 mL, the total gas flow rate was 500 mL / min, containing 0.25% SO2, 0.5% CO, and the remainder N2. The reaction temperature was 250–400 °C. A heating belt was installed at the tail end of the quartz tube, and the temperature was kept constant at 120 °C. Sulfur vapor, along with other tail gases, passed through the heating belt and entered the cold hydrazine, where it solidified and was collected. The catalyst's efficiency in converting SO2 to sulfur is evaluated in [reference needed]. Figure 1 .
[0070] (3) Comparative Results: Without microwave calcination, the catalyst template showed a maximum SO2 conversion rate of only 61.5% in the catalyst activity test within the temperature range of 250–400℃. This is mainly because the bonding force between the carbon nanofiber hollow tubes and carbon nanospheres is relatively weak after hydrothermal treatment. Heating in a conventional tube furnace can lead to uneven heating, causing the carbon nanofiber hollow tubes and carbon nanospheres to crack and break during calcination due to uneven heating, ultimately resulting in a decrease in catalyst activity.
[0071] Comparative Example 3
[0072] (1) Catalyst preparation: Except for the impregnation method used in step (3) to load the active component onto the template, the other conditions are the same as in Example 3;
[0073] (2) Activity Test: The catalyst dosage was 1 mL, the total gas flow rate was 500 mL / min, containing 0.25% SO2, 0.5% CO, and the remainder N2. The reaction temperature was 250–400 °C. A heating belt was installed at the tail end of the quartz tube, and the temperature was kept constant at 120 °C. Sulfur vapor, along with other tail gases, passed through the heating belt and entered the cold hydrazine, where it solidified and was collected. The catalyst's efficiency in converting SO2 to sulfur is evaluated in [reference needed]. Figure 1 .
[0074] (3) Comparative results: The active component was loaded onto the template using the impregnation method. In the catalyst activity test, the highest catalytic conversion rate of SO2 was only 52.1% in the temperature range of 250-400℃. This is mainly because the active component lost the high temperature and high pressure driving conditions of hydrothermal conditions, the loading of the active component on the template decreased, and after the template was removed by calcination, the mass per unit volume of the active component of the catalyst decreased, which ultimately led to the decrease in the activity of the catalyst.
Claims
1. A method for preparing a nanofiber catalyst for SO2 to sulfur production, characterized in that: The preparation method includes the following steps: (1) Preparation of hollow carbon nanofiber tubes The wood was immersed in hot alkaline solution and hot acid solution in turn. After the acid immersion was completed, it was rinsed, ground and sieved. Then it was transferred to a high-temperature carbonization furnace and roasted with nitrogen gas to finally obtain carbon nanofiber hollow tubes. (2) Preparation of catalyst template The carbon nanofiber hollow tubes prepared in step (1) were added to a glucose aqueous solution and subjected to a hydrothermal reaction. After the hydrothermal reaction was completed, microwave calcination was performed to finally obtain the catalyst template. (3) Loading of active components and removal of template Manganese nitrate, cerium nitrate and cobalt nitrate are dissolved in deionized water to form an active component precursor solution. The template material obtained in step (2) is then added to the precursor solution and subjected to a hydrothermal reaction. After the reaction is completed, the material is transferred to a muffle furnace for high-temperature calcination at 500℃~600℃ to remove the template and finally obtain the catalyst.
2. The preparation method according to claim 1, characterized in that: The wood mentioned in step (1) is cylindrical apricot or peach wood with a diameter of 4-6 mm and a height of 20-25 mm.
3. The preparation method according to claim 1, characterized in that: The hot alkaline solution mentioned in step (1) is a 10~15 mol / L NaOH solution at 60℃~70℃, and the immersion time is 1h~2h.
4. The preparation method according to claim 1, characterized in that: The hot acid solution mentioned in step (1) is a 7~9 mol / L H2SO4 solution at 50℃~60℃, and the immersion time is 3h~5h.
5. The preparation method according to claim 1, characterized in that: Step (1) The sieve used for sieving is 150~250 mesh.
6. The preparation method according to claim 1, characterized in that: The calcination temperature in step (1) is 600℃~800℃, the calcination time is 5~6h, and the nitrogen gas introduction rate is 20~40mL / min.
7. The preparation method according to claim 1, characterized in that: The mass ratio of the carbon nanofiber hollow tube to glucose in step (2) is (5~7):(2~3).
8. The preparation method according to claim 7, characterized in that: The hydrothermal reaction temperature in step (2) is 160℃~190℃, and the hydrothermal reaction time is 12h~16h.
9. The preparation method according to claim 7, characterized in that: The microwave power of microwave calcination in step (2) is 1~5kW, the microwave calcination temperature is 800℃~900℃, the microwave calcination time is 15~30min, and the microwave calcination is carried out under a nitrogen atmosphere of 30~60ml / min.
10. The preparation method according to claim 1, characterized in that: The mass ratio of manganese nitrate, cerium nitrate, cobalt nitrate and deionized water in step (3) is (0.5~2):(1~4):(0.5~3):(3~9); The mass ratio of the precursor solution to the template obtained in step (2) is (8~12):(1~5); The temperature of the hydrothermal reaction in step (3) is 200℃~220℃, and the time of the hydrothermal reaction is 3h~5h; In step (3), the high-temperature roasting time is 8h~10h.
11. A nanofiber catalyst for the production of sulfur from SO2, characterized in that, The catalyst is prepared by the method described in any one of claims 1 to 10.
12. The application of the catalyst of claim 11 in the catalytic reduction of sulfur dioxide by carbon monoxide to sulfur.