CeO2 loaded Fe-B catalyst as well as preparation and application thereof

Abstract

The invention discloses a CeO2 loaded Fe-B catalyst as well as preparation and application thereof. The CeO2 loaded Fe-B catalyst is prepared by a preparation method comprising the following steps: (1) loading ferric salt on a CeO2 carrier by wet impregnation, then drying and calcining in a nitrogen atmosphere to obtain a calcined product, and dispersing the calcined product in water to obtain a dispersion liquid; and (2) under the protection of nitrogen, dropwise adding a boron-alkali mixed solution into the dispersion liquid, stirring to react, separating, washing and drying the generated precipitate after the reaction is finished, and finally calcining the dried product under the protection of nitrogen to obtain the CeO2 loaded Fe-B catalyst. The invention provides application of the CeO2-loaded Fe-B catalyst in preparation of chlorine by catalytic oxidation of hydrogen chloride. By optimizing the preparation process, the catalyst has excellent activity and stability, so that the efficiency of converting HCl into Cl2 is greatly improved, and meanwhile, the cost and the environmental burden are reduced.

Description

Technical Field

[0001] This invention belongs to the field of catalytic oxidation of hydrogen chloride to produce chlorine, specifically relating to a CeO2-supported Fe-B catalyst, its preparation method, and its application in the catalytic oxidation of hydrogen chloride to produce chlorine. Technical Background

[0002] Chlorine (Cl2) is an indispensable key chemical raw material in modern manufacturing, widely used in the production of various chemical products and daily necessities, including chlorinated alkanes, chlorinated aromatics, plastics, phosgene, rubber, optical fibers, and disinfectants. However, in many chlorine-containing organic reactions, the utilization rate of chlorine atoms is low, leading to the generation of a large amount of byproduct HCl. Notably, in about one-third of Cl2 derivatives, such as polyurethane (PU) and polycarbonate (PC), chlorine atoms are not utilized, resulting in a chlorine atom utilization rate of zero. Although this byproduct HCl can be used in the production of polyvinyl chloride (PVC), market demand for PVC is far lower than that for PC and PU, making it difficult for the PVC industry to absorb the increasing HCl production. Direct neutralization to produce hydrochloric acid is also considered a less than ideal solution. Therefore, how to efficiently handle excess byproduct HCl and perform value-added conversion has become an urgent problem to be solved.

[0003] For a long time, industry has been seeking the most economical, efficient, and environmentally friendly method to treat large quantities of byproduct HCl. Converting byproduct HCl into Cl2 to achieve chlorine resource recycling is undoubtedly the best choice in line with the principles of green chemistry. Industrially, HCl is typically converted to Cl2 through electrolysis, direct oxidation, and catalytic oxidation. However, the first two methods are not only energy-intensive but also environmentally unfriendly; in contrast, catalytic oxidation is more widely used in industrial applications due to its high efficiency and environmental friendliness. The most representative process is the Sumitomo process using RuO2 / TiO2 catalysts, which can reduce the reaction temperature to 300℃ and increase the conversion rate to 90-95%, realizing the industrialization of HCl catalytic oxidation. Although Ru-based Deacon catalysts exhibit excellent activity in catalytic reactions, they also face challenges such as the high price of ruthenium and the tendency for active components to sinter. Therefore, finding low-cost alternative catalysts with excellent thermal stability has become a critical issue that urgently needs to be addressed.

[0004] Against this backdrop, CeO2-supported metastable Fe-B based nanocrystalline alloy catalysts, with their unique crystal structure and composition, exhibit unique catalytic properties distinct from traditional catalysts, making them a highly promising alternative. Iron and boron are relatively inexpensive, and compared to noble metal catalysts, Fe-B / CeO2 catalysts offer significant economic advantages, making them suitable for large-scale industrial applications. Furthermore, CeO2 as a support can modulate the electronic structure of the Fe-B alloy, thereby increasing the number and efficiency of catalytic active sites. This results in excellent activity and selectivity in the chlorination-hydrogenation reaction, and the catalyst maintains stable performance even after long-term operation. In addition, the high hardness, good corrosion resistance, and mechanical strength of the Fe-B alloy enable it to remain stable under harsh operating conditions, extending the catalyst's lifespan. Despite this, research on supported Fe-B catalysts is scarce.

[0005] In view of the above challenges, this study developed an innovative CeO2-supported Fe-B catalyst and explored its application potential in the production of chlorine from hydrogen chlorination, aiming to provide new solutions to existing technical problems and promote the development of chlorine-containing industries towards a greener and more sustainable direction. Summary of the Invention

[0006] The objective of this invention is to develop a CeO2-supported Fe-B catalyst, its preparation method, and its application in the catalytic oxidation of hydrogen chloride to chlorine. This invention optimizes the synthesis process to ensure the catalyst possesses excellent activity and stability, thereby significantly improving the efficiency of HCl to Cl2 conversion while reducing cost and environmental impact.

[0007] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a CeO2-supported Fe-B catalyst, which can be prepared by a method comprising the following steps:

[0009] (1) Iron salt is loaded onto CeO2 support by wet impregnation, and then dried and calcined in nitrogen atmosphere to obtain calcined product. The calcined product is dispersed in water to obtain dispersion, and the obtained dispersion is placed in ice water bath. The feeding ratio of iron salt and CeO2 support is 3-30:100, which is calculated as the mass ratio of Fe element in iron salt to CeO2 support.

[0010] (2) Under nitrogen protection, the boron-alkali mixed solution is added dropwise to the dispersion obtained in step (1) and stirred to react. After the reaction is complete, the precipitate is separated, washed, and dried. Finally, the dried product is calcined at 500-600℃ for 4-6 hours under nitrogen protection to obtain the CeO2-supported Fe-B catalyst. The boron-alkali mixed solution is made of boron source reducing agent, strong base, and water, wherein the concentration of boron source reducing agent is 1.6-2 mol / L, and the molar ratio of the ions is B. 3- :OH - =10:1; the ratio of the amount of the boron-alkali mixed solution to the dispersion is 3.5-4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

[0011] Preferably, the feeding ratio of the iron salt and CeO2 support is 5-20:100, based on the mass ratio of Fe element in the iron salt to CeO2 support, and more preferably 7-15:100.

[0012] Preferably, the iron salt is selected from one of ferric nitrate, ferric chloride, ferric sulfate, and ferrous sulfate.

[0013] Preferably, the calcination temperature in step (1) is 600°C.

[0014] Preferably, the calcination time in step (1) is 4-6 hours.

[0015] Preferably, the strong alkali mentioned in step (2) is selected from sodium hydroxide and potassium hydroxide.

[0016] Preferably, the boron source reducing agent mentioned in step (2) is selected from sodium borohydride and potassium borohydride.

[0017] Preferably, in the boron-alkali mixed solution described in step (2), the concentration of the boron source reducing agent is 2 mol / L.

[0018] Preferably, the ratio of the amount of boron-alkali mixed solution to the amount of dispersion in step (2) is 4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

[0019] Preferably, the stirring reaction rate in step (2) is 500-1000 rpm and the stirring reaction time is 6-8 h.

[0020] Preferably, the drying temperature in step (2) is 40-90°C, more preferably 50-80°C, even more preferably 60-70°C, and most preferably 60°C.

[0021] Preferably, the calcination temperature in step (2) is 500°C.

[0022] Preferably, the calcination time in step (2) is 6 hours.

[0023] In a second aspect, the present invention provides a method for preparing the CeO2-supported Fe-B catalyst described in the first aspect, comprising the following steps:

[0024] (1) Iron salt is loaded onto CeO2 support by wet impregnation, and then dried and calcined in nitrogen atmosphere to obtain calcined product. The calcined product is dispersed in water to obtain dispersion, and the obtained dispersion is placed in ice water bath. The feeding ratio of iron salt and CeO2 support is 3-30:100, which is calculated as the mass ratio of Fe element in iron salt to CeO2 support.

[0025] (2) Under nitrogen protection, the boron-alkali mixed solution is added dropwise to the dispersion obtained in step (1) and stirred to react. After the reaction is complete, the precipitate is separated, washed, and dried. Finally, the dried product is calcined at 400-600℃ for 4-6 hours under nitrogen protection to obtain CeO2-supported Fe-B catalyst. The boron-alkali mixed solution is made of boron source reducing agent, strong base, and water, wherein the concentration of boron source reducing agent is 1.6-2 mol / L, and the molar ratio of the ions is B. 3- :OH - =10:1; the ratio of the amount of the boron-alkali mixed solution to the dispersion is 3.5-4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

[0026] Preferably, the feeding ratio of the iron salt and CeO2 support is 5-20:100, based on the mass ratio of Fe element in the iron salt to CeO2 support, and more preferably 7-15:100.

[0027] Preferably, the iron salt is selected from one of ferric nitrate, ferric chloride, ferric sulfate, and ferrous sulfate.

[0028] Preferably, the impregnation in step (1) is ultrasonic impregnation, that is, impregnation under 5kW ultrasonic conditions for 6-8 hours.

[0029] Preferably, the drying in step (1) is performed at 90-110°C for 12 hours.

[0030] Preferably, the calcination temperature in step (1) is 600°C.

[0031] Preferably, the strong alkali mentioned in step (2) is selected from sodium hydroxide and potassium hydroxide.

[0032] Preferably, the boron source reducing agent mentioned in step (2) is selected from sodium borohydride and potassium borohydride.

[0033] Preferably, in the boron-alkali mixed solution described in step (2), the concentration of the boron source reducing agent is 0.5-3 mol / L, more preferably 1-2 mol / L, even more preferably 1.6-2 mol / L, and most preferably 2 mol / L.

[0034] Preferably, the ratio of the amount of boron-alkali mixed solution to the amount of dispersion in step (2) is 4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

[0035] Preferably, in step (2), the boron base mixture is added dropwise to the dispersion obtained in step (1) at a rate of 1 mL / min.

[0036] Preferably, the stirring reaction in step (2) is carried out at a rate of 500-1000 rpm for 6-8 hours.

[0037] Preferably, in step (2), the washing is performed by washing with deionized water and ethanol 3-5 times each.

[0038] Preferably, the drying in step (2) is vacuum drying, and the drying temperature is 40-90℃, more preferably 50-80℃, even more preferably 60-70℃, and most preferably 60℃.

[0039] Preferably, the calcination temperature in step (2) is 500°C.

[0040] Preferably, the calcination time in step (2) is 6 hours.

[0041] Thirdly, the present invention provides an application of the CeO2-supported Fe-B catalyst described in the first aspect in the catalytic oxidation of hydrogen chloride to chlorine.

[0042] Preferably, the reaction conditions for producing chlorine by hydroxyl chloride are: reaction temperature 400–450℃, reaction pressure 0.1 MPa, molar ratio of raw gas n(HCl) / n(O2) = 3–1 / 2, and hydrogen chloride gas space velocity 1–150 h⁻¹. -1 .

[0043] In a specific embodiment of the present invention, the application is implemented as follows:

[0044] The CeO2-supported Fe-B catalyst was placed in a fixed-bed reactor. The gas flow rate was adjusted and the temperature was increased. Then, hydrogen chloride and oxygen were introduced into the fixed-bed reactor through flow meters to control their flow rates and react to generate chlorine gas.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] 1. CeO2 itself has good thermal and chemical stability, which can protect Fe-B alloys from corrosion and deactivation under harsh working conditions; at the same time, the presence of the support can effectively improve the sintering problem of the catalyst.

[0047] 2. CeO2 can regulate the electronic structure of Fe-B alloys, enhance their adsorption capacity and conversion efficiency for HCl molecules, and thus improve catalytic activity.

[0048] 3. Compared with traditional precious metal catalysts, the use of CeO2 / Fe-B composite catalyst for HCl oxidation is more environmentally friendly, reducing energy consumption and by-product generation.

[0049] 4. There may be a synergistic effect between CeO2 and Fe-B, which can optimize the reaction path through interfacial interactions and achieve a higher HCl conversion rate.

[0050] In summary, the cerium oxide-supported Fe-B catalyst and its preparation method described in this invention provide a novel technical route for achieving efficient, economical, and environmentally friendly HCl oxidation to Cl2. Detailed Implementation

[0051] The present invention will be illustrated below with specific examples. It should be noted that the embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention, which is not limited thereto in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0052] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained through conventional technical means or commercially available.

[0053] Example 1

[0054] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0055] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0056] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0057] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0058] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0059] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0060] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0061] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0062] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The generated chlorine gas was determined by iodometry, while unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the hydrogen chloride conversion rate was 96%, and after 500 hours, it was 95%, showing no significant decrease. After the reaction was completed, there was no obvious catalyst agglomeration problem.

[0063] Comparative Example 1 (Changing the Carrier)

[0064] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0065] 2) Take 3g of Al2O3 and add it to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0066] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0067] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0068] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0069] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0070] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0071] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / Al2O3 with a loading of 7 wt%.

[0072] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 87%, and after 500 hours, it was 85%.

[0073] Comparative Example 2 (Changing the Carrier)

[0074] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0075] 2) Add 3g of TiO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0076] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0077] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0078] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0079] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0080] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0081] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / TiO2 with a loading of 7 wt%.

[0082] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometric titration, while unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 84%, and after 500 hours of reaction, the conversion rate was also 84%.

[0083] Comparative Example 3 (Changing the Carrier)

[0084] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0085] 2) Add 3g of SiO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0086] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0087] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0088] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0089] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0090] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0091] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product with a 7 wt% loading of Fe-B / SiO2.

[0092] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 80%, and after 500 hours, it was 78%.

[0093] Comparative Example 4 (without carrier)

[0094] 1) Weigh 1.515g of ferric nitrate nonahydrate, dissolve it in 18.75ml of deionized water and mix well to obtain a 0.2mol / L ferric nitrate solution.

[0095] 2) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.06g of sodium hydroxide and dissolve it in 7.5ml of water. After mixing evenly, weigh 0.57g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0096] 3) Add the mixed solution obtained in step 2) to the solution in step 1) in the ice water bath at a rate of 1 ml / min using a peristaltic pump, and stir vigorously for 30 minutes under a nitrogen atmosphere to obtain a black precipitate.

[0097] 4) Under a nitrogen atmosphere, wash the precipitate obtained in step 3) three times each with deionized water and ethanol, and then dry it in a vacuum oven at 60°C for 6 hours.

[0098] 5) Calcine the dried product obtained in step 4) at 600°C for 6 hours under an argon atmosphere.

[0099] 6) Load 0.5g of the calcined catalyst from step 5) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The generated chlorine gas was determined by iodometric titration, and unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the hydrogen chloride conversion rate was 93%, and after 500 hours, it was 92%, showing no significant decrease. However, severe catalyst agglomeration was observed after the reaction. Through Example 1 and Comparative Examples 1, 2, 3, and 4, it can be seen that the catalytic activity using CeO2 as the support is significantly higher than that of other conventional supports, and the presence of the support effectively improves the catalyst sintering problem.

[0100] Example 2

[0101] 1) Weigh 0.61g of ferric chloride and dissolve it in 5ml of deionized water and mix well.

[0102] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0103] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0104] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0105] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0106] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0107] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0108] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0109] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas generated was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 94%, and after 500 hours of reaction, the conversion rate was 92%, showing no significant decrease.

[0110] Comparative Example 5 (reducing the concentration of the boron-alkali mixed solution)

[0111] 1) Weigh 0.61g of ferric chloride and dissolve it in 5ml of deionized water and mix well.

[0112] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0113] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0114] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0115] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 11.2ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 1mol / L.

[0116] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0117] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0118] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0119] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 75%, and after 500 hours, the conversion rate was 70%.

[0120] Comparative Example 6 (reducing the proportion of ferroboron)

[0121] 1) Weigh 0.61g of ferric chloride and dissolve it in 5ml of deionized water and mix well.

[0122] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0123] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0124] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0125] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.03g of sodium hydroxide and dissolve it in 3.8ml of water. After mixing evenly, weigh 0.285g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0126] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0127] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0128] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0129] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 63%, and after 500 hours, it was 58%.

[0130] Examples 2 and Comparative Examples 5 and 6 show that low sodium borohydride solution concentration and boron-iron molar ratio may lead to incomplete reduction and failure to generate effective active substances.

[0131] Example 3

[0132] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0133] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0134] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0135] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0136] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.063g of potassium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.6075g of potassium borohydride and dissolve it in the solution to obtain a potassium borohydride mixed solution with a concentration of 2mol / L.

[0137] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0138] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0139] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0140] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas generated was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 96%, and after 500 hours, it was 94%, showing no significant decrease.

[0141] Comparative Example 7 (changing the final calcination temperature)

[0142] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0143] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0144] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0145] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0146] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.063g of potassium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.6075g of potassium borohydride and dissolve it in the solution to obtain a potassium borohydride mixed solution with a concentration of 2mol / L.

[0147] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0148] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0149] 8) The catalyst dried in step 7) was calcined at 300°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0150] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometric titration, while unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 75%, and after 500 hours, it was 72%.

[0151] Comparative Example 8 (Changing the final calcination temperature)

[0152] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0153] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0154] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0155] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0156] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.063g of potassium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.6075g of potassium borohydride and dissolve it in the solution to obtain a potassium borohydride mixed solution with a concentration of 2mol / L.

[0157] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0158] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0159] 8) The catalyst dried in step 7) was calcined at 800°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0160] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 70%, and after 500 hours, it was 68%.

[0161] Through Example 3 and Comparative Examples 7 and 8, it can be seen that if the final calcination temperature is too high during the catalyst preparation process, it will lead to high-temperature decomposition of the active phase, and if the final calcination temperature is too low, it will lead to rapid deactivation of the catalyst.

[0162] Example 4

[0163] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0164] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0165] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0166] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0167] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0168] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0169] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0170] 8) The catalyst dried in step 7) was calcined at 600°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0171] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas generated was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 97%, and after 500 hours, it was 94%, showing no significant decrease.

[0172] Comparative Example 9 (without intermediate calcination)

[0173] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0174] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0175] 3) Disperse the initially loaded catalyst from step 2) into 30 ml of deionized water.

[0176] 4) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0177] 5) Under the protection of ice water bath and nitrogen, the mixed solution of step 4) is added to the dispersion of step 4) at a rate of 1 ml / min using a peristaltic pump and the mixture is vigorously stirred at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0178] 6) The catalyst from step 5) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0179] 7) The catalyst dried in step 6) was calcined at 600°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0180] 8) Load 0.5g of the calcined catalyst from step 7) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 83%, and after 500 hours, it was 17%.

[0181] Comparative Example 10 (without final calcination)

[0182] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0183] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0184] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0185] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0186] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.045g of sodium hydroxide and dissolve it in 5.6ml of water. After mixing evenly, weigh 0.426g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0187] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0188] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0189] 8) Load 0.5g of the dried catalyst from step 7) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas produced was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 74%, and after 500 hours, it was 16%.

[0190] Through Example 4 and Comparative Examples 9 and 10, it can be seen that omitting the calcination step in the catalyst preparation process, whether in the middle or at the end, will lead to insufficient stability of the active phase supported on the support, affecting the service life of the catalyst.

[0191] Example 5

[0192] 1) Weigh 1.515g of ferric nitrate nonahydrate and dissolve it in 5ml of deionized water and mix well.

[0193] 2) Add 3g of CeO2 to the solution in step 1) and impregnate it with ultrasound (5kW) for 7h. Then take out the treated solid and dry it in an oven at 90℃ for 12h to obtain the initially loaded catalyst.

[0194] 3) The catalyst from step 2) was calcined at 600°C for 6 hours under a nitrogen atmosphere.

[0195] 4) Disperse the calcined catalyst from step 3) into 30 ml of deionized water.

[0196] 5) Under the conditions of ice-water bath and nitrogen atmosphere, weigh 0.06g of sodium hydroxide and dissolve it in 7.5ml of water. After mixing evenly, weigh 0.57g of sodium borohydride and dissolve it in the solution to obtain a sodium borohydride mixed solution with a concentration of 2mol / L.

[0197] 6) Under ice-water bath and nitrogen protection, the mixed solution from step 5) was added to the dispersion from step 4) at a rate of 1 ml / min using a peristaltic pump and stirred vigorously at a rate of 500 RPM for 6 h to obtain the reduced catalyst.

[0198] 7) The catalyst from step 6) was washed three times each with deionized water and ethanol under nitrogen protection, and then dried in a vacuum oven at 60°C for 6 hours.

[0199] 8) The catalyst dried in step 7) was calcined at 500°C for 6 h under a nitrogen atmosphere to obtain the final product Fe-B / CeO2 with a loading of 7 wt%.

[0200] 9) Load 0.5g of the calcined catalyst from step 8) into a micro fixed-bed reactor, and then introduce a mixture of hydrogen chloride and oxygen in a molar ratio of n(HCl):n(O2) = 1:1.4. The reaction temperature is 450℃, the reaction pressure is 0.1MPa, and the mass hourly space velocity of hydrogen chloride is 50h⁻¹. -1 The reaction products were absorbed with excess 0.2 mol / L potassium iodide solution. The chlorine gas generated was determined by iodometry, and the unreacted hydrogen chloride was obtained by acid-base titration. The conversion rate of hydrogen chloride was calculated from these results. After 30 hours of reaction, the conversion rate of hydrogen chloride was 94%, and after 500 hours, it was 95%, showing no significant decrease.

Claims

1. A CeO2-supported Fe-B catalyst, characterized in that: The CeO2-supported Fe-B catalyst was prepared by a method comprising the following steps: (1) Iron salt is loaded onto CeO2 support by wet impregnation, and then dried and calcined in nitrogen atmosphere to obtain calcined product. The calcined product is dispersed in water to obtain dispersion, and the obtained dispersion is placed in ice water bath. The feeding ratio of iron salt and CeO2 support is 3-30:100, which is calculated as the mass ratio of Fe element in iron salt to CeO2 support. (2) Under nitrogen protection, the boron-alkali mixed solution is added dropwise to the dispersion obtained in step (1) and stirred to react. After the reaction is complete, the precipitate is separated, washed, and dried. Finally, the dried product is calcined at 500-600℃ for 4-6 hours under nitrogen protection to obtain CeO2-supported Fe-B catalyst. The boron-alkali mixed solution is made of boron source reducing agent, strong base, and water, wherein the concentration of boron source reducing agent is 1.6-2 mol / L, and the molar ratio of the ions is B. 3- :OH - =10:1; the ratio of the amount of the boron-alkali mixed solution to the dispersion is 3.5-4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

2. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: The feeding ratio of the iron salt and CeO2 carrier is 5-20:100, preferably 7-15:100, based on the mass ratio of Fe element in the iron salt to CeO2 carrier.

3. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: The iron salt is selected from one of ferric nitrate, ferric chloride, ferric sulfate, and ferrous sulfate; the strong base is selected from one of sodium hydroxide and potassium hydroxide; and the boron source reducing agent is selected from one of sodium borohydride and potassium borohydride.

4. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: The calcination temperature in step (1) is 600℃; the calcination time is 4-6h.

5. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: In the boron-alkali mixed solution described in step (2), the concentration of the boron source reducing agent is 2 mol / L.

6. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: The ratio of the amount of boron-alkali mixed solution to the amount of dispersion in step (2) is 4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

7. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: The stirring reaction rate in step (2) is 500-1000 rpm, and the stirring reaction time is 6-8 h.

8. The CeO2-supported Fe-B catalyst as described in claim 1, characterized in that: The calcination temperature in step (2) is 500℃ and the calcination time is 6h.

9. A method for preparing a CeO2-supported Fe-B catalyst as described in any one of claims 1-8, characterized in that: The preparation method includes the following steps: (1) Iron salt is loaded onto CeO2 support by wet impregnation, and then dried and calcined in nitrogen atmosphere to obtain calcined product. The calcined product is dispersed in water to obtain dispersion, and the obtained dispersion is placed in ice water bath. The feeding ratio of iron salt and CeO2 support is 3-30:100, which is calculated as the mass ratio of Fe element in iron salt to CeO2 support. (2) Under nitrogen protection, the boron-alkali mixed solution is added dropwise to the dispersion obtained in step (1) and stirred to react. After the reaction is complete, the precipitate is separated, washed, and dried. Finally, the dried product is calcined at 400-600℃ for 4-6 hours under nitrogen protection to obtain CeO2-supported Fe-B catalyst. The boron-alkali mixed solution is made of boron source reducing agent, strong base, and water, wherein the concentration of boron source reducing agent is 1.6-2 mol / L, and the molar ratio of the ions is B. 3- :OH - =10:1; the ratio of the amount of the boron-alkali mixed solution to the dispersion is 3.5-4, calculated as the molar ratio of B contained in the boron source reducing agent to Fe in the iron salt used to obtain the dispersion.

10. The application of a CeO2-supported Fe-B catalyst as described in any one of claims 1-8 in the catalytic oxidation of hydrogen chloride to chlorine.