A denitration catalyst with low sulfur dioxide oxidation rate and preparation and application thereof

Abstract

The application discloses a denitration catalyst with low sulfur dioxide oxidation rate, a preparation method of the denitration catalyst and application of the denitration catalyst in selective catalytic reduction of nitrogen oxides by ammonia. The denitration catalyst with low sulfur dioxide oxidation rate is a titanium dioxide supported vanadium pentoxide, molybdenum oxide and cerium oxide catalyst which is treated by phosphating. The preparation method comprises the following steps: (1) preparing a first solid-liquid mixture in which vanadium pentoxide precursor, molybdenum oxide precursor, cerium oxide precursor and titanium dioxide are uniformly dispersed, drying the first solid-liquid mixture, grinding and calcining to obtain an intermediate product; (2) preparing a second solid-liquid mixture in which the intermediate product and a precursor for phosphating are uniformly dispersed, drying the second solid-liquid mixture, grinding and calcining to obtain the denitration catalyst with low sulfur dioxide oxidation rate. The application realizes low-cost control of NO x at the same time reducing the generation of sulfur trioxide.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air pollution control, in particular to a denitration catalyst with low sulfur dioxide oxidation rate and a preparation method and application thereof. BACKGROUND

[0002] Nitrogen oxides (NO x ) and sulfur dioxide (SO2) coexist widely in many industrial flue gas, such as coal-fired power plants, coke ovens of steel industry, biomass boilers, etc. Among them, NO x is an important precursor of ozone (O3) and PM 2.5 , and SO2 is easily oxidized to sulfur trioxide (SO3) by catalyst, SO3 is easy to corrode the pipeline system of subsequent equipment, in order to prevent corrosion, the heating temperature of subsequent flue gas has to be increased, which increases energy consumption and reduces the efficiency of air preheater; at the same time, SO3 is easy to form ammonium bisulfate with ammonia in flue gas, which causes the blockage of gas pipeline. In addition, SO3 can cause harm to human health. Therefore, under the premise of removing NO x , reducing the oxidation of SO2 to SO3 is of great significance to environmental protection and human health.

[0003] At present, the catalyst for removing nitrogen oxides reduces the oxidation rate of SO2 by reducing the SO2 at the inlet, that is, a desulfurization device is arranged before the denitration device to remove SO2 in flue gas, but the temperature of flue gas after desulfurization is usually low, and it still needs to be heated to the reaction temperature before entering the denitration device, which increases the energy consumption of flue gas treatment system. Secondly, there is also a method of subsequent SO3 treatment, but after the removal of nitrogen oxides, a large part of SO3 exists in the form of sulfate species, which increases the difficulty of treatment.

[0004] Regarding the simultaneous occurrence of NH3-SCR reaction and SO2 oxidation reaction in the removal of nitrogen oxides, in order to selectively occur SCR reaction without SO2 oxidation reaction, the catalyst needs to have selective adsorption of NO x and NH3 and reduce the reaction energy barrier, while reducing the adsorption of SO2 and increasing the oxidation energy barrier. Generally, the catalyst for removing nitrogen oxides has high redox performance, and high redox performance will cause the occurrence of SCR reaction and SO2 oxidation at high temperature, so that the removal efficiency of nitrogen oxides and the oxidation rate of SO2 present a common reaction trend, therefore, this is also the main problem of the current catalyst design. In addition, the composition of actual industrial flue gas is complex, and the water resistance of the catalyst is also a key factor that needs to be considered in the catalyst design. Therefore, it is of great application prospect and development significance to develop a catalyst for removing nitrogen oxides with wide temperature window, high activity, high stability and low SO2 oxidation rate.

[0005] The Chinese patent document with the publication number CN108187657A discloses a thin-wall SCR denitration catalyst with low sulfur dioxide oxidation rate and a preparation method thereof. Vanadium pentoxide is loaded on the surface of a titanium dioxide catalyst to remove NO x at the same time, and the oxidation of SO2 is inhibited, but the catalyst has problems such as complex preparation process, difficult control of sulfur dioxide oxidation rate under thin wall, and unstable denitration performance.

[0006] The Chinese patent document with the publication number CN106994301A discloses a high-efficiency SCR denitration structure capable of reducing the conversion rate of sulfur dioxide / sulfur trioxide. The oxidation rate of sulfur dioxide on the SCR catalyst is reduced through multi-stage combustion and air recycling, but the structure is relatively complex, the energy consumption is high, and the oxidation rate of sulfur dioxide is not directly reduced on the catalyst.

[0007] The Chinese patent document with the publication number CN103240077A discloses a denitration catalyst with low sulfur dioxide oxidation rate and a preparation method thereof. The catalyst is prepared by mixing titanium dioxide, vanadium pentoxide, tungsten trioxide, niobium oxide, rare earth oxide, and silicon-aluminum composite oxide, thereby reducing the oxidation rate of sulfur dioxide while maintaining the SCR catalytic activity, but the activity is still not high, and there is still a large space for reducing the oxidation rate of sulfur dioxide.

[0008] Although the above-mentioned documents provide certain help for the development of a catalyst for removing nitrogen oxides with low sulfur dioxide oxidation rate, there are still disadvantages such as narrow temperature window, high preparation cost, poor denitration performance, poor water resistance, and the like, which hinder the industrial application of NH3-SCR catalysts in high-sulfur dioxide flue gas treatment.

[0009] Therefore, it is of wide application prospect and development significance to develop a new NH3-SCR catalyst that can be used in the SCR denitration process of high-sulfur dioxide flue gas, has a wide temperature window, high activity, low sulfur dioxide oxidation, water resistance, and relatively low preparation cost. SUMMARY

[0010] In view of the above technical problems and the deficiencies in the field, the present application provides a denitration catalyst with low sulfur dioxide oxidation rate and a preparation method and application thereof. The denitration catalyst of the present application has a wide temperature window, high activity, high stability, and the like, realizes low-cost control of NO x at the same time reduces the generation of sulfur trioxide, and overcomes the problems of SO2 oxidation and water resistance of the catalyst existing in the current denitration catalyst.

[0011] [1] A denitration catalyst with low sulfur dioxide oxidation rate, the denitration catalyst with low sulfur dioxide oxidation rate is a phosphatized titanium dioxide supported vanadium pentoxide, molybdenum oxide and cerium oxide catalyst, which can be denoted as P-VMoCe / Ti.

[0012] The present application solves the above technical problems by adopting a multi-metal loading structure combined with phosphatization treatment, which reduces the oxidation of SO2 while ensuring high denitration performance. Among them, vanadium pentoxide (V2O5) is a good medium-high temperature denitration catalyst, which can achieve efficient removal of NO x ; Molybdenum oxide (MO3) further improves the denitration efficiency, stability and water resistance of the catalyst. In addition, cerium oxide (CeO2) can improve the dispersion of V2O5 on the carrier and form a vanadium-cerium interaction to protect V2O5 from SO2 adsorption; Phosphatization further improves the adsorption of NH3 on the catalyst and reduces the adsorption of SO2. The above comprehensive effects effectively reduce the oxidation of SO2 in the denitration environment and effectively improve the removal efficiency of nitrogen oxides. At the same time, the catalyst has good water resistance, so it can maintain good nitrogen oxide removal efficiency in actual industrial flue gas.

[0013] In the denitration catalyst with low sulfur dioxide oxidation rate, the mass fraction of vanadium element is 0.5% to 1%, for example 0.7%, the mass fraction of molybdenum element is 4% to 8%, for example 6%, the mass fraction of cerium element is 2% to 6%, preferably 3% to 5%, further preferably 4%, and the mass fraction of phosphorus element is 3% to 7%, preferably 4% to 6%, further preferably 5%, based on 100% of the mass of titanium dioxide. The catalyst under the preferred conditions can exhibit 100% nitrogen oxide removal efficiency, more than 98% N2 selectivity and less than 0.8% sulfur dioxide oxidation rate in the temperature window of 250 to 350℃.

[0014] [2] A preparation method of the denitration catalyst with low sulfur dioxide oxidation rate according to [1], comprising the steps of:

[0015] (1) preparing a first solid-liquid mixture uniformly dispersed with vanadium pentoxide precursor, molybdenum oxide precursor, cerium oxide precursor and titanium dioxide, drying the first solid-liquid mixture, grinding and calcining to obtain an intermediate product;

[0016] (2) preparing a second solid-liquid mixture uniformly dispersed with the intermediate product and a precursor for phosphatization, drying the second solid-liquid mixture, grinding and calcining to obtain the denitration catalyst with low sulfur dioxide oxidation rate.

[0017] In the preparation method of the present application, firstly, a transition metal catalyst supported on titanium dioxide is prepared by a wet impregnation method, and then a phosphating treatment is performed to introduce a phosphoric acid functional group, so as to obtain a multi-metal supported phosphating type catalyst for treating nitrogen oxides in a sulfur-containing waste gas. The main active sites for removing nitrogen oxides in the catalyst are vanadium active sites, the molybdenum sites serve to broaden the temperature window and enhance the water resistance, and the cerium enhances the acidity and stability of the vanadium sites, in combination with the phosphating to enhance the inhibition of SO2 adsorption and inhibit the oxidation of SO2 to form the intermediate VOSO4. NH3 is adsorbed on the vanadium sites, and NO reacts with NH3 on the vanadium sites to generate water and nitrogen; and SO2 is difficult to be adsorbed on the vanadium sites, and the formed VOSO4 intermediate is difficult to be decomposed to generate SO3. The multi-metal supported phosphating type catalyst has the advantages of improving the removal efficiency of the catalyst for nitrogen oxides, limiting the oxidation of SO2, and having high N2 selectivity.

[0018] In step (1), the vanadium pentoxide precursor can be ammonium metavanadate.

[0019] In step (1), the molybdenum oxide precursor can be ammonium heptamolybdate.

[0020] In step (1), the cerium oxide precursor can be at least one of cerium nitrate and cerium ammonium nitrate.

[0021] In step (1), the titanium dioxide can be P25.

[0022] In step (1), the calcination temperature can be 450-550°C, for example, 500°C, and the time can be 4-6h, for example, 5h.

[0023] In step (2), the precursor for phosphating can be at least one of ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

[0024] In step (2), the calcination temperature can be 350-550°C, preferably 400-500°C, and further preferably 400°C, and the time can be 2-5h, preferably 3-5h, and further preferably 3h. Under the preferred conditions, the catalyst can exhibit 100% removal efficiency of nitrogen oxides, N2 selectivity of more than 98%, and SO2 oxidation rate of less than 0.8% in the temperature window of 250-350°C.

[0025] [3] The application of the denitration catalyst with low sulfur dioxide oxidation rate in the selective catalytic reduction of ammonia to remove nitrogen oxides according to [1].

[0026] In the process of the application, the denitration catalyst with low sulfur dioxide oxidation rate can inhibit the oxidation of sulfur dioxide and reduce the generation of sulfur trioxide.

[0027] [3] In the process of the application, the temperature for selective catalytic reduction of nitrogen oxides by ammonia can be 200-450°C, further 250-400°C.

[0028] [3] In the process of the application, the environment for selective catalytic reduction of nitrogen oxides by ammonia can contain water vapor. Further, the volume fraction of water vapor can be 0.1%-20%.

[0029] [4] A method for selective catalytic reduction of nitrogen oxides by ammonia, using the denitration catalyst with low sulfur dioxide oxidation rate of [1].

[0030] [4] In the method, the denitration catalyst with low sulfur dioxide oxidation rate can inhibit sulfur dioxide oxidation and reduce sulfur trioxide formation.

[0031] [4] In the method, the temperature for selective catalytic reduction of nitrogen oxides by ammonia can be 200-450°C, further 250-400°C.

[0032] [4] In the method, the environment for selective catalytic reduction of nitrogen oxides by ammonia can contain water vapor. Further, the volume fraction of water vapor can be 0.1%-20%.

[0033] The denitration catalyst with low sulfur dioxide oxidation rate of the application is particularly suitable for removing nitrogen oxides in flue gas in the front-end treatment of flue gas treatment engineering.

[0034] Compared with the prior art, the application has the following beneficial effects:

[0035] 1) The sulfur resistance of the denitration catalyst does not mean low sulfur dioxide oxidation rate. The sulfur-resistant denitration catalyst can have high sulfur dioxide oxidation rate. The multi-metal supported phosphatized catalyst prepared in the application can effectively remove nitrogen oxides within a wide temperature window and can effectively inhibit sulfur dioxide oxidation and reduce the formation of sulfur trioxide in the exhaust gas.

[0036] 2) The catalyst prepared in the application has certain water resistance, improves the N2 selectivity of the reaction, and can meet the complex working conditions under actual conditions.

[0037] 3) The application uses transition metals and P25 as precursors to achieve efficient removal of nitrogen oxides under the condition of low SO2 oxidation rate on the catalyst, thereby reducing the cost of removing pollutants. DETAILED DESCRIPTION

[0038] The application will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not to limit the scope of the application.

[0039] Example 1

[0040] Catalyst preparation:

[0041] (1) A certain amount of vanadium pentoxide, molybdenum oxide, and cerium oxide precursor is added to a certain amount of P25 titanium dioxide, and the mass ratio of vanadium pentoxide, molybdenum oxide, and cerium oxide to the carrier titanium dioxide is controlled to be 0.7%, 6%, and 2%, respectively. Then 100 mL of deionized water is added, and stirring is performed for 5 h and ultrasonic treatment is performed for 1 h to disperse uniformly. The carrier P25 titanium dioxide is added in an amount of 8 g, the vanadium pentoxide precursor NH4VO3 is added in an amount of 0.072 g, the molybdenum oxide precursor H 24 Mo7N6O 24 ·4H2O is added in an amount of 0.588 g, and the cerium oxide precursor (NH4)2Ce(NO3)6 is added in an amount of 0.509 g;

[0042] (2) After uniform dispersion, the solid-liquid mixture is dried at 120 degrees Celsius for 12 h. The solid product is ground into powder and sieved to 200 meshes. The powder is calcined at 500 degrees Celsius for 5 h to obtain an intermediate product;

[0043] (3) The intermediate product prepared in step (2) is added with 0.518 g of diammonium hydrogen phosphate ((NH4)2HPO4) to maintain the mass ratio of P element to the carrier TiO2 at 5%, and deionized water is added for stirring for 4 h and ultrasonic treatment for 0.5 h to disperse uniformly;

[0044] (4) The solid-liquid mixture is dried at 120 degrees Celsius for 12 h. The solid product is ground into powder and sieved to 200 meshes. The powder is calcined at 400 degrees Celsius for 3 h to obtain the catalyst of Example 1.

[0045] Example 2

[0046] The difference from Example 1 is only that the amount of the cerium oxide precursor (NH4)2Ce(NO3)6 is increased to 1.019 g, and the mass ratio of cerium oxide to the carrier titanium dioxide is controlled to be 4%. The rest is the same, and the catalyst of Example 2 is obtained.

[0047] Example 3

[0048] The difference from Example 1 is only that the amount of the cerium oxide precursor (NH4)2Ce(NO3)6 is increased to 1.528 g, and the mass ratio of cerium oxide to the carrier titanium dioxide is controlled to be 6%. The rest is the same, and the catalyst of Example 3 is obtained.

[0049] Example 4

[0050] The difference from Example 2 is only that the calcination temperature and time in (4) are changed to 500 degrees Celsius and 5 h. The rest is the same, and the catalyst of Example 4 is obtained.

[0051] Example 5

[0052] The difference from Example 2 is only that the amount of diammonium hydrogen phosphate ((NH4)2HPO4) is changed to 0.310 g to keep the mass ratio of P element to carrier TiO2 at 3%, and the rest is the same, to obtain the catalyst of Example 5.

[0053] Example 6

[0054] The difference from Example 2 is only that the amount of diammonium hydrogen phosphate ((NH4)2HPO4) is changed to 0.725 g to keep the mass ratio of P element to carrier TiO2 at 7%, and the rest is the same, to obtain the catalyst of Example 6.

[0055] Example 7

[0056] The difference from Example 6 is only that the amount of cerium oxide precursor (NH4)2Ce(NO3)6 is increased to 1.528 g to control the mass ratio of cerium oxide to carrier titanium dioxide at 6%, and the rest is the same, to obtain the catalyst of Example 7.

[0057] Example 8

[0058] Catalyst preparation:

[0059] (1) A certain amount of vanadium pentoxide, molybdenum oxide, and cerium oxide precursor is added to a certain amount of P25 titanium dioxide, and a phosphating precursor is added at the same time, to control the mass ratio of vanadium pentoxide, molybdenum oxide, cerium oxide, P element to carrier titanium dioxide at 0.7%, 6%, 4%, and 5%, respectively. Then 100 mL of deionized water is added, and stirring is performed for 5 h and ultrasonic treatment is performed for 1 h to disperse uniformly. The carrier P25 titanium dioxide is added in an amount of 8 g, the vanadium pentoxide precursor NH4VO3 is added in an amount of 0.072 g, the molybdenum oxide precursor H 24 Mo7N6O 24 ·4H2O is added in an amount of 0.588 g, and the cerium oxide precursor (NH4)2Ce(NO3)6 is added in an amount of 1.019 g, and the phosphating precursor diammonium hydrogen phosphate ((NH4)2HPO4) is added in an amount of 0.518 g;

[0060] (2) After uniform dispersion, the solid-liquid mixture is dried at 120 degrees Celsius for 12 h, and the solid product is ground into powder and sieved to 200 mesh, and the powder is calcined at 500 degrees Celsius for 5 h to obtain the catalyst of Example 8.

[0061] Comparative Example 1

[0062] Catalyst preparation:

[0063] (1) A certain amount of vanadium pentoxide, molybdenum oxide precursor is added to a certain amount of P25 titanium dioxide, the mass ratio of vanadium pentoxide, molybdenum oxide to carrier titanium dioxide is controlled to be 0.7%, 6%, then 100 mL of deionized water is added, and stirring is carried out for 5h and ultrasonic treatment for 1h to disperse uniformly. The carrier P25 titanium dioxide is added to 8g, the vanadium pentoxide precursor NH4VO3 is added to 0.072g, the molybdenum oxide precursor H 24 Mo7N6O 24 ·4H2O is added to 0.588g,;

[0064] (2) After uniform dispersion, the solid-liquid mixture is dried at 120 degrees Celsius for 12h, the solid product is ground into powder and sieved to 200 meshes, and the powder is calcined at 500 degrees Celsius for 5h to obtain an intermediate product, namely the catalyst of Comparative Example 1.

[0065] Comparative Example 2

[0066] The difference from Example 1 is only that no cerium oxide precursor (NH4)2Ce(NO3)6 is added, and the rest is the same, to obtain the catalyst of Comparative Example 2.

[0067] Application Example 1

[0068] The catalysts prepared in Examples 1-8 and Comparative Examples 1-2 are subjected to selective catalytic reduction test of nitrogen oxide (NO x ) to explore the best component ratio and preparation conditions. Specifically as follows:

[0069] The activity experiment is carried out on a fixed bed reactor, the catalyst loading is 2.3mL, and the particle size is 40-60 meshes. The initial gas volume concentration is: [NO] = 500ppm, [NH3] = 500ppm, [SO2] = 200ppm, [O2] = 5vol%, [H2O] = 5vol%, N2 is the carrier gas, GHSV (gas space velocity) = 40000h -1 . The test reaction temperature is specifically taken as 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, and the NO conversion rate test data at 1h of reaction is shown in Table 1. In addition, NO x In an ideal case, it should be selectively oxidized to N2 and H2O, therefore, N2 selectivity is also an important evaluation factor of catalyst performance. In this experiment, the N2 selectivity in the activity experiment is further investigated, and the data is shown in Table 2.

[0070] The results are expressed by NO conversion rate and N2 selectivity, and the calculation method is shown in the following formula:

[0071]

[0072] The test data is shown in Table 1 and Table 2.

[0073] Table 1 Catalytic reduction efficiency of NO / %

[0074]

[0075] Table 2 De-NOx N2 selectivity / %

[0076]

[0077] By comparing the comparative example 2 with the examples 1-3, it can be found that the optimum proportion of cerium oxide loading of the multi-metal loaded phosphatized catalyst in the present application is 4% in the activity test experiment of removing nitrogen oxides, and has 100% nitrogen oxide removal efficiency and more than 98% N2 selectivity in the temperature window of 250-400℃.

[0078] By comparing the examples 2, 5, 6, it can be found that the optimum proportion of phosphatized loading of phosphorus element of the multi-metal loaded phosphatized catalyst in the present application is 5% in the activity test experiment of removing nitrogen oxides.

[0079] By comparing the examples 2, 4, 8, it can be found that the multi-metal loaded phosphatized catalyst in the present application needs to be prepared by two-step method, and the optimum condition of the second calcination is calcination at 400℃ for 3h in the activity test experiment of removing nitrogen oxides.

[0080] Application Example 2

[0081] The catalysts prepared in the examples 1-8 and the comparative examples 1-2 were subjected to the oxidation rate determination experiment of sulfur dioxide (SO2) to explore whether the catalyst with high nitrogen oxide removal rate has lower SO2 oxidation rate. Specifically as follows:

[0082] The determination experiment was carried out on a fixed bed reactor, and the catalyst loading was 2.3mL with a particle size of 40-60 mesh. The initial gas volume concentration was: [NO] = 300ppm, [NH3] = 300ppm, [SO2] = 2000ppm, [O2] = 5vol%, [H2O] = 5vol%, N2 was the carrier gas, and GHSV (gas space velocity) = 40000h -1 . The test reaction temperature was specifically taken as 250℃, 300℃, 350℃, 400℃, and the SO2 oxidation rate test data at the reaction time of 1h were shown in Table 3.

[0083] The result was expressed by the SO2 oxidation rate, and the calculation method was shown in the following formula:

[0084]

[0085] The test data were shown in Table 3.

[0086] Table 3 Oxidation rate of SO2 / %

[0087]

[0088] By comparing the comparative examples 1, 2 and the example 2, it can be found that the multi-metal loaded phosphatized catalyst P-VMoCe / Ti of the present application maintains 100% conversion rate of removing nitrogen oxides, and maintains N2 selectivity of more than 98%, and SO2 oxidation rate of less than 0.8% in the temperature range of 250-400 degrees Celsius.

[0089] The multi-metal loaded phosphatized catalyst of the present application has the advantages of: 1. wide temperature window, high denitration activity, and low SO2 oxidation rate; 2. good water resistance, sulfur resistance, and stability.

[0090] Furthermore, it is to be understood that even though numerous characteristics and embodiments of the application have been set forth in the foregoing description, many modifications and / or changes of the embodiments of the application in accordance with the scope of the application as set forth in the claims below and / or the scope of equivalents thereto can be affected.

Claims

1. A denitration catalyst having a low sulfur dioxide oxidation rate, characterized by, The denitration catalyst with low sulfur dioxide oxidation rate is a phosphating-treated titanium dioxide supported vanadium pentoxide, molybdenum oxide and cerium oxide catalyst; In the denitration catalyst with low sulfur dioxide oxidation rate, the mass percentage of vanadium element is 0.5% to 1%, the mass percentage of molybdenum element is 4% to 8%, the mass percentage of cerium element is 2% to 6%, and the mass percentage of phosphorus element is 3% to 7%, based on 100% of the mass of titanium dioxide; The preparation method of the denitration catalyst with low sulfur dioxide oxidation rate comprises the following steps: (1) preparing a first solid-liquid mixture in which vanadium pentoxide precursor, molybdenum oxide precursor, cerium oxide precursor and titanium dioxide are uniformly dispersed, drying the first solid-liquid mixture, and then grinding and calcining to obtain an intermediate product; (2) preparing a second solid-liquid mixture in which the intermediate product and a precursor for phosphating are uniformly dispersed, drying the second solid-liquid mixture, and then grinding and calcining to obtain the denitration catalyst with low sulfur dioxide oxidation rate; In step (2), the calcination temperature is 350 to 550°C.

2. The De-NOx catalyst with low sulfur dioxide oxidation rate according to claim 1, characterized by, In the denitration catalyst with low sulfur dioxide oxidation rate, the mass percentage of cerium element is 3% to 5%, and the mass percentage of phosphorus element is 4% to 6%, based on 100% of the mass of titanium dioxide.

3. The denitration catalyst with low sulfur dioxide oxidation rate according to claim 2, characterized in that, In the denitration catalyst with low sulfur dioxide oxidation rate, the mass percentage of cerium element is 4%, and the mass percentage of phosphorus element is 5%, based on 100% of the mass of titanium dioxide.

4. The method for producing a denitration catalyst having a low sulfur dioxide oxidation rate according to any one of claims 1 to 3, characterized by, The preparation method comprises the following steps: (1) preparing a first solid-liquid mixture in which vanadium pentoxide precursor, molybdenum oxide precursor, cerium oxide precursor and titanium dioxide are uniformly dispersed, drying the first solid-liquid mixture, and then grinding and calcining to obtain an intermediate product; (2) preparing a second solid-liquid mixture in which the intermediate product and a precursor for phosphating are uniformly dispersed, drying the second solid-liquid mixture, and then grinding and calcining to obtain the denitration catalyst with low sulfur dioxide oxidation rate; In step (2), the calcination temperature is 350 to 550°C.

5. The preparation method according to claim 4, characterized in that, In step (1): The vanadium pentoxide precursor is ammonium metavanadate; The molybdenum oxide precursor is ammonium heptamolybdate; The cerium oxide precursor is at least one of cerium nitrate and cerium ammonium nitrate; The titanium dioxide is P25; The calcination temperature is 450 to 550°C, and the time is 4 to 6 hours.

6. The preparation method according to claim 4, characterized in that, In step (2): The precursor for phosphating is at least one of ammonium dihydrogen phosphate and diammonium hydrogen phosphate; The calcination temperature is 400 to 500°C, and the time is 3 to 5 hours.

7. Use of the denitration catalyst with low sulfur dioxide oxidation rate according to any one of claims 1 to 3 in selective catalytic reduction removal of nitrogen oxides by ammonia.

8. Use according to claim 7, characterized in that, In the use process: The denitration catalyst with low sulfur dioxide oxidation rate can inhibit the oxidation of sulfur dioxide and reduce the generation of sulfur trioxide; The temperature for selective catalytic reduction removal of nitrogen oxides by ammonia is 200 to 450°C; The environment for selective catalytic reduction removal of nitrogen oxides by ammonia contains water vapor, and the volume fraction of water vapor is 0.1% to 20%.

9. Use according to claim 8, characterized in that, In the use process: the temperature for selective catalytic reduction removal of nitrogen oxides by ammonia is 250 to 400°C.

10. A method for the selective catalytic reduction of nitrogen oxides with ammonia, characterized in that The denitration catalyst with low sulfur dioxide oxidation rate according to any one of claims 1 to 3.

11. The method for the selective catalytic reduction of nitrogen oxides with ammonia according to claim 10, characterized in that In the method: The denitration catalyst with low sulfur dioxide oxidation rate can inhibit the oxidation of sulfur dioxide and reduce the generation of sulfur trioxide; The temperature for removing nitrogen oxides by selective catalytic reduction of ammonia is 200-450 DEG C; The environment for removing nitrogen oxides by selective catalytic reduction of ammonia contains water vapor, and the volume fraction of water vapor is 0.1%-20%.

12. The method of claim 11 wherein the ammonia is removed by selective catalytic reduction of nitrogen oxides. In the method: the temperature for removing nitrogen oxides by selective catalytic reduction of ammonia is 250-400 DEG C.

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