A high-activity, anti-fluctuation vanadium / cerium / molybdenum-titanium catalyst and a preparation method thereof

Abstract

The application provides a high-activity and anti-fluctuation vanadium / cerium / molybdenum-titanium catalyst, which comprises the following components in the total mass of the catalyst being 100%: active component 1: V2O5, content being 5.0 wt%-10.0 wt%; active component 2: CeO2, content being 3.0 wt%-8.0 wt%; active component 3: MoO3, content being 2.0 wt%-7.0 wt%; carrier: TiO2, content being the balance; the SO2 catalytic oxidation catalyst with CeO2, V2O5 and MoO3 as the active components and anatase TiO2 as the carrier realizes multiple synergistic effects of high specific surface area-multiple valence state oxide coupling-oxygen migration channel enhancement at the structural level, and has comprehensive advantages in low-temperature activity, anti-poisoning, redox cycle stability and carrier-active component interaction and the like. The system can maintain high SO2 to SO3 conversion rate and stability under the working conditions of complex and severe fluctuation of waste acid cracking regeneration gas.

Description

Technical Field

[0001] This invention relates to the field of industrial catalyst technology, and in particular to a highly active, fluctuation-resistant vanadium oxide / cerium / molybdenum-titanium catalyst and its preparation method. Background Technology

[0002] Industries such as petrochemicals, titanium dioxide production, and metal smelting generate large quantities of waste sulfuric acid, especially alkylation waste sulfuric acid. This type of waste acid not only contains high concentrations of sulfuric acid components but also impurities such as organic hydrocarbons, byproduct esters, heavy metals, and halide ions, exhibiting strong corrosiveness and high pollution levels. Direct discharge would cause serious environmental damage. Currently, high-temperature pyrolysis and regeneration technology is commonly used in industry to treat waste sulfuric acid for resource recovery. This process involves pyrolyzing waste acid at high temperatures, causing the organic matter to react with sulfuric acid to generate gases such as SO2, H2O, and CO2. The SO2 is then catalytically oxidized to SO3, which is then absorbed to produce fresh sulfuric acid, achieving a balance between resource recovery and pollution reduction. The core reaction in this process is the catalytic oxidation of SO2, and its reaction formula is: .

[0003] Currently, vanadium-based catalysts are widely used in industry for SO2 oxidation. These catalysts use V2O5 as the main active component, combined with alkali metal sulfates such as K2SO4 and Cs2SO4 as promoters, and TiO2 (anatase type) or SiO2 as the support. They possess both high thermal stability and catalytic efficiency, exhibiting excellent activity and service life in traditional pyrite roasting acid production processes. However, the operating conditions of waste acid regeneration are far more complex than conventional acid production. In addition to SO2 and O2, the cracked gas contains CO, CO2, H2O vapors, and various organic residual components, with drastic fluctuations in composition and flow rate. For example, when the feed or temperature of the cracking furnace changes, the SO2 concentration may rapidly increase from 3% to over 10% within minutes. This fluctuation disrupts the steady-state equilibrium of the catalytic reaction, leading to a sudden rise in bed temperature (i.e., "runaway temperature"), and in severe cases, even causing catalyst sintering or loss of activity.

[0004] Furthermore, the cracked gas often contains halogen elements such as F and Cl, as well as small amounts of heavy metal ions. These components readily react with V2O5 or promoters in the catalyst to generate volatile or inactive species, leading to the loss of active components or poisoning and deactivation of the catalyst. Meanwhile, traditional vanadium-based catalysts exhibit poor low-temperature activity, generally requiring temperatures above 400℃ to achieve high conversion rates. This not only increases system energy consumption but also hinders the efficient utilization of waste heat from the cracked gas.

[0005] In summary, while existing vanadium-based catalysts exhibit stability in traditional acid production, they struggle to meet the complex requirements of waste acid regeneration environments characterized by high volatility, high toxicity, and numerous impurities. Furthermore, their performance is affected by rapid changes in SO2 concentration. 5+ / V 4+ The slow response of the redox cycle leads to insufficient dynamic adaptability of the catalytic reaction; insufficient activity at low temperatures limits the overall energy efficiency of the reaction system. Therefore, there is an urgent need to develop a novel vanadium-based catalyst that combines high and low temperature activity, strong resistance to poisoning, and the ability to adapt to drastic fluctuations in SO concentration, to provide more efficient and stable catalytic material support for the regeneration process of waste acid cracking gas. Summary of the Invention

[0006] Purpose of the invention: This invention addresses the problems of insufficient stability and low-temperature activity of vanadium catalysts used in waste acid treatment when dealing with SO2 concentration fluctuations in the prior art. It provides a highly active, fluctuation-resistant vanadium oxide / cerium / molybdenum-titanium catalyst and its preparation method. By utilizing its unique oxygen storage / release properties and synergistic effect with V2O5, the catalyst's fluctuation resistance and low-temperature activity are significantly improved.

[0007] The technical solution of the present invention: To achieve the above objectives, in a first aspect, the present invention provides a highly active, fluctuation-resistant vanadium oxide / cerium / molybdenum-titanium catalyst, comprising the following components based on 100% of the total mass of the catalyst: Active component 1: V₂O₅, with a content of 5.0 wt%~10.0 wt%; Active component 2: CeO2, with a content of 3.0 wt%~8.0 wt%; Active component 3: MoO3, with a content of 2.0 wt%~7.0 wt%; Carrier: TiO2, content is balance.

[0008] Furthermore, the content of V2O5 is 6.0 wt% to 8.0 wt%; the content of CeO2 is 4.0 wt% to 6.0 wt%; and the content of MoO3 is 4.0 wt% to 5.0 wt%.

[0009] In some embodiments, the TiO2 support is anatase type, with a specific surface area of ​​50-120 m². 2 / g.

[0010] In some embodiments, the method for preparing TiO2 includes the following steps: Tetraisopropoxy titanium was added to a solvent, acetylacetone was added, and the mixture was magnetically stirred to obtain a tetraisopropoxy titanium solution. Deionized water and HCl were mixed to obtain an acidified aqueous phase. The aqueous phase was slowly added dropwise to the tetraisopropoxy titanium solution, and the mixture was stirred at room temperature to form a sol. The solution was aged by heating in a water bath, dried in an oven, and then calcined after heat treatment to obtain anatase TiO2.

[0011] In some embodiments, the water bath temperature for water bath heating and aging is 40~60℃, and the aging time is 6-12h.

[0012] In some embodiments, the drying temperature in the oven is 80~100℃, and the drying time is 12h.

[0013] In some embodiments, the heat treatment temperature is 220~250℃ and the treatment time is 2~3h; the calcination temperature is 350~400℃ and the calcination time is 1~2h.

[0014] In a second aspect, the present invention provides a method for preparing the vanadium oxide / cerium / molybdenum-titanium catalyst, specifically comprising the following steps: S1: Dissolve the vanadium source compound, cerium source compound and molybdenum source compound in an acidic aqueous solution and stir to mix evenly to obtain a mixed solution; S2: The mixture obtained in S1 is evenly sprayed or dropped onto the TiO2 support of the anatase crystal phase; S3: After drying the support obtained in S2, the vanadium oxide / cerium / molybdenum-titanium catalyst is obtained by calcining it in an air atmosphere.

[0015] In some embodiments, the vanadium source compound is selected from at least one of vanadium pentoxide, ammonium vanadate, vanadium pentoxide hydrate, vanadium oxalate, vanadium oxyphosphate, and vanadate; more preferably, vanadium pentoxide is selected as the inorganic vanadium source.

[0016] In some embodiments, the cerium source compound is selected from at least one of cerium sulfate, cerium oxide, cerium nitrate, cerium ammonium nitrate, cerium carbonate, cerium chloride, cerium ammonium sulfate, cerium acetate, cerium oxalate, cerium hydroxide, cerium phosphate, cerium trifluoromethanesulfonate, cerium sulfate, and cerium perchlorate.

[0017] In some embodiments, the molybdenum source compound is selected from at least one of molybdenum trioxide, molybdenum acetylacetonate, ammonium molybdate, sodium molybdate, etc.

[0018] In some embodiments, the drying temperature is 100~120°C and the drying time is 4~6 hours.

[0019] In some embodiments, the calcination temperature is 450~550℃ and the calcination time is 4~6 hours.

[0020] In some embodiments, the total mass ratio of the vanadium source compound, cerium source compound, and molybdenum source compound to the TiO2 support of the anatase crystal phase is 1 to 8:10.

[0021] Beneficial effects: The main advantages of this invention are: 1. Excellent low-temperature activity: The introduction of CeO2 forms a strong interaction with V2O5 and MoO3, changing the electronic environment and surface acidity of vanadium species and creating new, more active interfacial sites (VO-Ce). This enables the catalyst to have a high SO2 conversion rate at lower temperatures (e.g., 280-320℃), which is beneficial for reducing energy consumption and rapid start-up.

[0022] 2. Excellent resistance to concentration fluctuations: This is the core advantage of this invention. CeO2 has a unique oxygen storage capacity; when the O2 concentration in the waste acid gas is momentarily low, CeO2 can release its lattice oxygen (O2). 2- ), replenish the oxygen required for the reaction in a timely manner to prevent V 5+ V that is excessively reduced to inactive 3+ When the O2 concentration recovers or becomes too high, CeO2 can quickly store excess oxygen. This "oxygen buffer" effect allows the catalyst to cope with drastic fluctuations in SO2 and O2 concentrations, maintain the continuous stability of reaction activity, and prevent bed temperature runaway.

[0023] 3. Enhanced thermal and structural stability: The introduction of CeO2 and MoO3 helps stabilize the crystal structure of anatase TiO2, inhibiting its sintering at high temperatures and its transformation to the rutile phase, thereby extending the catalyst's lifespan.

[0024] 4. The preparation method is simple and easy to industrialize: This invention adopts the classic equal volume impregnation method, which has mature technology, simple process, low equipment requirements, and is very suitable for large-scale industrial production. Attached Figure Description

[0025] Figure 1 This is a comparison of the low-temperature activity of the catalyst prepared in Example 1 of the present invention with that of Comparative Example 6 (conventional VW / Ti catalyst).

[0026] Figure 2 This is a comparison chart of the stability test results of the catalyst prepared in Example 1 of this invention and Comparative Example 6 under simulated concentration fluctuation conditions.

[0027] Figure 3 This is a physical image of the catalyst prepared in Example 1 of the present invention. Detailed Implementation

[0028] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0029] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade reagents.

[0030] Preparation example of anatase TiO2 10.0 mL of tetraisopropoxy titanium was added to 50 mL of anhydrous isopropanol, followed by 1.0 mL of acetylacetone. The mixture was magnetically stirred for 10 min to form a complex, yielding a tetraisopropoxy titanium solution. 20 mL of deionized water was mixed with 10 mL of 0.1 M HCl to obtain an acidified aqueous phase. The acidified aqueous phase was added dropwise to the tetraisopropoxy titanium solution over 30 min. The mixture was stirred at room temperature for 2 h to form a sol. The sol was then aged in a water bath at 60 °C for 10 h, dried in an oven at 100 °C for 12 h, and then heat-treated at 250 °C for 2 h at a rate of 5 °C / min. Finally, the sol was calcined at 400 °C for 2 h to obtain anatase TiO2.

[0031] The specific surface area of ​​the anatase TiO2 was measured to be 90 m². 2 / g.

[0032] Preparation example of rutile phase TiO2 10.0 mL of tetraisopropoxy titanium was added to 50 mL of anhydrous isopropanol, followed by 1.0 mL of acetylacetone. The mixture was magnetically stirred for 10 min to form a complex, yielding a tetraisopropoxy titanium solution. 20 mL of deionized water was mixed with 10 mL of 0.1 M HCl to obtain an acidified aqueous phase. The acidified aqueous phase was added dropwise to the tetraisopropoxy titanium solution over 30 min. The mixture was stirred at room temperature for 2 h to form a sol. The sol was aged in a water bath at 60 °C for 10 h, dried in an oven at 100 °C for 12 h, and then heat-treated at 350 °C for 2 h at a rate of 5 °C / min. Finally, the sol was calcined at 800 °C for 2 h to obtain rutile TiO2.

[0033] Preparation example of TiO2 in brookite phase 10.0 mL of tetraisopropoxy titanium was added to 50 mL of anhydrous isopropanol, and 1.0 mL of oxalic acid was added. The mixture was magnetically stirred for 10 min to form a complex, resulting in a tetraisopropoxy titanium solution. 20 mL of deionized water was mixed with 0.1 g of NH4F to obtain an aqueous phase. The aqueous phase was added dropwise to the tetraisopropoxy titanium solution over 30 min. The mixture was then hydrothermally treated at 200 °C for 12 h. After cooling, the mixture was centrifuged, washed, dried, and calcined at 350 °C to obtain TiO2 of the brookite phase.

[0034] Example of preparation of submicron sheet-like tungsten disulfide Weigh out 3.2g of ammonium metatungstate, 9.5g of sodium sulfide, 1.6g of polyvinylpyrrolidone, and 160ml of deionized water, mix them evenly, place them in a hydrothermal reactor, heat to 140℃ and hydrothermally react for 8 hours. After the reaction is complete, filter, wash three times with anhydrous ethanol and deionized water respectively, and finally dry in an oven at 40℃ for 24 hours to obtain submicron sheet-like tungsten disulfide.

[0035] Example 1 Formula: V2O5: 5.0 wt%, CeO2: 3.0 wt%, MoO3: 4.0 wt%, TiO2 of anatase phase: 88.0 wt%.

[0036] S1: Weigh out 6.4g of ammonium metavanadate (NH4VO3; equivalent to approximately 5.0g of V2O5), 7.5g of cerium nitrate (Ce(NO3)3·6H2O, equivalent to approximately 5.0g of CeO2), and 5g of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O; equivalent to approximately 4.0g of MoO3.

[0037] S2: Dissolve the above raw materials in 150 mL of deionized water, add 10.8 g of oxalic acid while stirring in a 70°C water bath until a clear solution is obtained.

[0038] S3: Measure 88 g of anatase TiO2 support (specific surface area ~90m²) 2 The solution prepared by S2 was slowly and evenly sprayed onto a continuously tumbling TiO2 support; the impregnated material was dried at 110°C for 5 hours. Then, it was calcined in a muffle furnace at 500°C under air atmosphere for 5 hours to obtain the catalyst.

[0039] Example 2 Formula: V2O5: 7.0 wt%, CeO2: 5.0 wt%, MoO3: 5.0 wt%, TiO2 of anatase phase: 83.0 wt%.

[0040] S1: Weigh out 9g of ammonium metavanadate (NH4VO3; equivalent to approximately 5.0g of V2O5), 13g of cerium nitrate (Ce(NO3)3·6H2O, equivalent to approximately 5.0g of CeO2), and 6.1g of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O; equivalent to approximately 4.0g of MoO3.

[0041] S2: Dissolve the above raw materials in 150 mL of deionized water, add 10.8 g of oxalic acid while stirring in a 70°C water bath until a clear solution is obtained.

[0042] S3: Measure 83 g of anatase TiO2 support (specific surface area ~90 m²) 2 The solution prepared by S2 was slowly and evenly sprayed onto a continuously tumbling TiO2 support; the impregnated material was dried at 110°C for 5 hours. Then, it was calcined in a muffle furnace at 500°C under air atmosphere for 5 hours to obtain the catalyst.

[0043] Example 3 Formula: V2O5: 10.0 wt%, CeO2: 8.0 wt%, MoO3: 7.0 wt%, TiO2 of anatase phase: 75.0 wt%.

[0044] S1: Weigh out 12.9g of ammonium metavanadate (NH4VO3; equivalent to approximately 5.0g of V2O5), 20.5g of cerium nitrate (Ce(NO3)3·6H2O, equivalent to approximately 5.0g of CeO2), and 8.6g of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O; equivalent to approximately 4.0g of MoO3.

[0045] S2: Dissolve the above raw materials in 150 mL of deionized water, add 10.8 g of oxalic acid while stirring in a 70°C water bath until a clear solution is obtained.

[0046] S3: Measure 75 g of anatase TiO2 support (specific surface area ~90 m²) 2 The solution prepared by S2 was slowly and evenly sprayed onto a continuously tumbling TiO2 support; the impregnated material was dried at 110°C for 5 hours. Then, it was calcined in a muffle furnace at 500°C under air atmosphere for 5 hours to obtain the catalyst.

[0047] Comparative Example 1 Formula: V2O5: 7.0 wt%, CeO2: 5.0 wt%, MoO3: 5.0 wt%, rutile phase TiO2: 83.0 wt%.

[0048] The preparation method is the same as in Example 1, with the raw material input amount adjusted accordingly.

[0049] Comparative Example 2 Formula: V2O5: 7.0 wt%, CeO2: 5.0 wt%, MoO3: 5.0 wt%, TiO2 of brookite phase: 83.0 wt%.

[0050] The preparation method is the same as in Example 1, with the raw material input amount adjusted accordingly.

[0051] Comparative Example 3 Formula: V2O5: 7.0 wt%, CeO2: 5.0 wt%, MoO3: 5.0 wt%, submicron sheet tungsten disulfide: 83.0 wt%.

[0052] The preparation method is the same as in Example 1, with the raw material input amount adjusted accordingly.

[0053] Comparative Example 4 Formula: V2O5: 10.0 wt%, CeO2: 7.0 wt%, TiO2 of anatase phase: 83.0 wt%.

[0054] The preparation method is the same as in Example 1, with the raw material input amount adjusted accordingly.

[0055] Comparative Example 5 Formula: V2O5: 7.0 wt%, MoO3: 5.0 wt%, TiO2 of anatase phase: 88.0 wt%.

[0056] The preparation method is the same as in Example 1, with the raw material input amount adjusted accordingly.

[0057] Comparative Example 6 A conventional VW / Ti catalyst was prepared as a comparison. The V2O5 content was 7.0 wt%, the WO3 content was 8.0 wt%, and TiO2 was the balance. The preparation method adopted the same equal-volume impregnation and calcination process as in Example 1.

[0058] Performance testing experiment The catalysts prepared in the above examples and comparative examples were pressed into tablets, crushed, and sieved to obtain 20-40 mesh particles for micro-reaction evaluation.

[0059] Evaluation conditions: The reactor was a fixed-bed quartz tube reactor with a catalyst loading of 1 mL. The simulated waste acid cracking gas composition was: SO2 6 vol%, O2 10 vol%, and N2 as the equilibrium gas; the space velocity was 3600 h⁻¹. -1 .

[0060] Test 1: Low-temperature activity. Starting from 340℃, the SO2 conversion rate (%) at a steady-state point was measured every 20℃ increase, and the temperature at which 90% conversion was achieved was recorded. The results are shown in Table 1. Figure 1 .

[0061] Test 2: Stability against fluctuations.

[0062] 1) Under 420℃ conditions, the system was first stabilized for 2 hours. Then, the SO2 concentration in the feed gas was switched between 4% and 10% every 30 minutes to simulate a drastic fluctuation condition. The SO2 conversion rate (%) of Example 1 and Comparative Example 6 was continuously tested over 12 hours. The data are as follows: Figure 2 As shown.

[0063] 2) Under different temperature conditions, the SO2 concentration in the raw gas was kept at 10% and the operation was stable for 12 hours. The SO2 conversion rate (%) of different materials was tested, and the data are shown in Table 2.

[0064] Table 1 Test Data

[0065] Table 2. SO2 conversion rate (%) of different materials as a function of temperature

[0066] V₂O₅ provides the main catalytic active center, which is activated by V₂O₅. 5+ / V 4+ The reversible redox cycle enables oxygen transfer; MoO3, as an activating component, can stabilize the dispersion state of V2O5 and regulate its acidity and alkalinity, preventing the sintering and loss of active components at high temperatures, while forming VO-Mo bonds to enhance oxygen migration ability; CeO2 has good oxygen storage / release properties, can dynamically regulate the oxygen concentration of the system, and enhance low-temperature activation ability and resistance to poisoning. The multivalent oxide interface (Ce-OV, Mo-OV) formed when the three coexist can increase the oxygen vacancy concentration and electron conductivity, making the redox cycle faster and more buffering against sudden changes in SO2 concentration. The low-temperature catalytic performance of this complex is significantly improved.

[0067] Compared to other types of carriers, anatase structures have more oxygen vacancies, providing more active sites for active components and enhancing their anchoring and electronic coupling. Rutile TiO2 has a relatively inert surface, limiting interfacial electron migration. While brookite TiO2 is stable, it has a lower specific surface area and its metal oxides are prone to aggregation. Therefore, it is better able to maintain the continuous stability of reactivity and reduce the impact of fluctuations.

[0068] A SO2 catalytic oxidation catalyst with CeO2, V2O5, and MoO3 as active components and anatase TiO2 as support achieves multiple synergistic effects at the structural level, including high specific surface area, coupling of multiple valence oxides, and enhanced oxygen migration channels. It exhibits comprehensive advantages in low-temperature activity, anti-toxicity, redox cycle stability, and support-active component interaction. This system maintains high SO2-to-SO3 conversion rate and stability even under complex and volatile operating conditions of waste acid pyrolysis regeneration gas.

[0069] This invention can also be implemented in various other ways. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes and modifications according to this invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A highly active, fluctuation-resistant vanadium oxide / cerium / molybdenum-titanium catalyst, characterized in that, based on the total mass of the catalyst (100%), Includes the following components: Active component 1: V₂O₅, with a content of 5.0 wt%~10.0 wt%; Active component 2: CeO2, with a content of 3.0 wt%~8.0 wt%; Active component 3: MoO3, with a content of 2.0 wt%~7.0 wt%; Carrier: TiO2, content is balance.

2. The vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 1, characterized in that, The content of V2O5 is 6.0 wt% to 8.0 wt%; the content of CeO2 is 4.0 wt% to 6.0 wt%; and the content of MoO3 is 4.0 wt% to 5.0 wt%.

3. The vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 1, characterized in that, The carrier TiO2 is anatase type, with a specific surface area of ​​50~120 m². 2 / g.

4. The vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 1, characterized in that, The method for preparing TiO2 includes the following steps: Tetraisopropoxy titanium was added to a solvent, acetylacetone was added, and the mixture was magnetically stirred to obtain a tetraisopropoxy titanium solution. Deionized water and HCl were mixed to obtain an acidified aqueous phase. The aqueous phase was slowly added dropwise to the tetraisopropoxy titanium solution, and the mixture was stirred at room temperature to form a sol. The solution was aged by heating in a water bath, dried in an oven, and then calcined after heat treatment to obtain anatase TiO2.

5. The vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 4, characterized in that, The water bath temperature for the water bath heating aging is 40~60℃, and the aging time is 6~12h; the oven drying temperature is 80~100℃, and the drying time is 12h; the heat treatment temperature is 220~250℃, and the treatment time is 2~3h; the calcination temperature is 350~400℃, and the calcination time is 1~2h.

6. The method for preparing the vanadium oxide / cerium / molybdenum-titanium catalyst according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Dissolve the vanadium source compound, cerium source compound and molybdenum source compound in an acidic aqueous solution and stir to mix evenly to obtain a mixed solution; S2: The mixture obtained in S1 is evenly sprayed or dropped onto the TiO2 support of the anatase crystal phase; S3: After drying the support obtained in S2, the vanadium oxide / cerium / molybdenum-titanium catalyst is obtained by calcining it in an air atmosphere.

7. The method for preparing the vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 6, characterized in that, The vanadium source compound is selected from at least one of vanadium pentoxide, ammonium vanadate, vanadium pentoxide hydrate, vanadium oxalate, vanadium oxalate, and vanadate; more preferably, vanadium pentoxide is selected as the inorganic vanadium source.

8. The method for preparing the vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 6, characterized in that, The cerium source compound is selected from at least one of cerium sulfate, cerium oxide, cerium nitrate, cerium ammonium nitrate, cerium carbonate, cerium chloride, cerium ammonium sulfate, cerium acetate, cerium oxalate, cerium hydroxide, cerium phosphate, cerium trifluoromethanesulfonate, cerium sulfate, and cerium perchlorate.

9. The method for preparing the vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 6, characterized in that, The molybdenum source compound is selected from at least one of molybdenum trioxide, molybdenum acetylacetonate, ammonium molybdate, and sodium molybdate.

10. The method for preparing the vanadium oxide / cerium / molybdenum-titanium catalyst according to claim 6, characterized in that, The drying temperature is 100~120℃ and the drying time is 4~6 hours; the calcination temperature is 450~550℃ and the calcination time is 4~6 hours; the total mass ratio of the vanadium source compound, cerium source compound and molybdenum source compound to the TiO2 support of the anatase crystal phase is 1~8:10.

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