CeWOx-coated SiO2 wide-temperature denitration catalyst as well as preparation method and application thereof

Abstract

The invention provides a CeWOx-coated SiO2 wide-temperature denitration catalyst as well as a preparation method and application thereof. According to the method, CeWOx microspheres are prepared through a hydrothermal method, and then the surface of the catalyst is coated with a layer of SiO2 shell through a controllable hydrolysis method, so that an active temperature window of the catalyst is widened, and meanwhile, the water-sulfur stability of the catalyst is improved. The preparation method has the advantages that the controllable thickness of the SiO2 shell layer is realized through synergism of the hydrolysis temperature, the addition amount of tetraethyl orthosilicate and the hydrolysis time. The CeWOx catalyst not coated with SiO2 can maintain 90% or above of denitration activity within the temperature range of 175-450 DEG C, the CeWOx coated SiO2 catalyst prepared by coating SiO2 has a wider active temperature range, 90% or above of denitration activity can be maintained within the temperature range of 180-550 DEG C, and the water and sulfur resistance stability of the CeWOx coated SiO2 catalyst is remarkably enhanced. The method is suitable for flue gas denitration in typical industries such as color / chemical industry, steel, electric power and cement.

Description

Technical Field

[0001] The present invention relates to a novel wide-temperature, water-sulfur-resistant, low-temperature, and efficient core-shell structure denitration catalyst, which belongs to the field of air pollution control technology and environmentally friendly catalytic materials and is suitable for flue gas denitration in typical industries such as nonferrous metals / chemicals, steel, electricity, and cement. Technical Background

[0002] People have come to realize that nitrogen oxides are the main air pollutants, which not only directly endanger human health, but are also the main cause of haze, acid rain, and photochemical smog. At present, the most widely used flue gas denitrification technology is selective catalytic reduction technology (SCR). V2O5-WO3 / TiO2 catalyst is one of the most commonly used commercial SCR denitrification catalysts. Its temperature window is 300-400°C and it is widely used in denitrification in the power industry. However, the flue gas conditions in the non-power industry are complex, the flue gas temperature is low, the fluctuation is large, and it contains water and sulfur, making V2O5-WO3 / TiO2 catalysts difficult to apply. And as the country proposes to further reduce NO x Total emission reduction of NO in flue gas from non-power industry x Ultra-low emissions become the key. At present, constructing a core-shell structure catalyst based on the active components of the SCR denitration catalyst is an effective strategy to improve its catalytic performance and water-sulfur stability. Chinese patents (CN114653397A), (CN109529816A), (CN108176349A), (CN102941083A) and other patents all enhance the catalytic performance and anti-poisoning ability of the catalyst by constructing a core-shell structure. However, the denitration activity temperature window is often narrow and the preparation process is complicated. Therefore, it is of great significance to develop a denitration catalyst with a simple preparation method, a wide temperature window and strong stability. Summary of the invention

[0003] The purpose of the present invention is to develop a wide temperature range denitration catalyst, which is intended to solve the problems of narrow active temperature range, high cost and poor stability against water and sulfur poisoning in existing denitration catalysts, and to provide a CeWO x @SiO2 wide temperature denitrification catalyst and its preparation method.

[0004] The specific technical scheme of the present invention is:

[0005] A CeWO x @SiO2 wide temperature denitrification catalyst, the catalyst is prepared by hydrothermal method CeWO x Microspheres are then deposited on CeWO x The surface of the microspheres is covered with a SiO2 shell.

[0006] A CeWO as above x @The preparation method of SiO2 wide temperature denitration catalyst, the preparation method of the catalyst is as follows:

[0007] (3)CeWO x Preparation of microspheres

[0008] The cerium salt and tungsten salt are dissolved in a mixture of water, ethanol and citric acid and mixed, and then a hydrothermal reaction is carried out. After the reaction, washing, drying and calcination are performed to obtain CeWO. x Microspheres;

[0009] Wherein: the molar ratio of Ce to W element is 1:(0.01-0.5); preferably: the molar ratio of Ce to W element is 1:(0.2-0.5).

[0010] (4) Preparation of core-shell catalysts

[0011] Will CeWO x Microspheres and hexadecyltrimethylammonium bromide are dispersed in a solvent and mixed evenly. After mixing evenly, ammonia water and formic acid are added and stirred evenly to obtain a mixed solution. Then, tetraethyl orthosilicate is slowly added to the mixed solution for reaction. After the reaction is completed, washing, drying and calcination are performed in sequence to obtain CeWO. x @SiO2 wide temperature denitrification catalyst.

[0012] In the above preparation method: in step (1), the hydrothermal reaction temperature is 150-180°C, and the hydrothermal time is 15-24h; the drying temperature is 60-80°C, and the drying time is 6-12h; the calcination temperature is 500-600°C, and the insulation time is 2-4h.

[0013] In the above preparation method: the citric acid in step (1) is a forming agent,

[0014] The mass ratio of water, ethanol and citric acid is 30-50:10-30:1-5.

[0015] In the above preparation method: in step (1), the mass ratio of the salt to the mixed solution is 2-4:55-65, the salt is cerium salt and tungsten salt, and the mixture is water, ethanol and citric acid.

[0016] In the above preparation method: the cetyltrimethylammonium bromide (CTAB) described in step (2) is a surface modifier, ammonia water is a pH regulator, and formic acid is a hydrolysis inducer.

[0017] In the above preparation method: in step (2), CeWO x The mass ratio of the microsphere, hexadecyltrimethyl bromide and tetraethyl orthosilicate is 0.1-2:0.1-1:0.1-2.

[0018] In the above preparation method: in step (2), CeWO xThe mass ratio of the micron ball to the ammonia water is 0.1-1:0.1-0.5, and the mass ratio of the ammonia water to the formic acid is 1-15:1.

[0019] In the above preparation method: in step (2), the reaction temperature is 50-80°C, and the reaction time is 1-6h; the drying temperature is 70-80°C, and the drying time is 7-8h; the calcination temperature is 450-550°C, and the calcination time is 3-4h.

[0020] In the technical solution of the present invention, the catalyst is used as a denitration catalyst; preferably, the denitration temperature is 100-550°C.

[0021] Beneficial effects:

[0022] The catalyst of the present invention is suitable for NH3-SCR denitration under complex working conditions. Its denitration efficiency is greater than 90% and N2 selectivity is greater than 95% in the temperature range of 180-550°C. Compared with the prior art, the catalyst system not only has a wider denitration active temperature window, but also has stronger water-sulfur stability. The preparation method first prepares CeWO by hydrothermal method. x Microspheres are coated with SiO2 shell by controlled hydrolysis. The thickness of SiO2 shell can be controlled by controlling the hydrolysis temperature, the amount of tetraethyl orthosilicate added and the reaction time. Compared with the existing denitration catalyst, the preparation method of the present invention is simple and low in cost. The prepared core-shell catalyst has a wide temperature window, excellent catalytic performance and anti-poisoning ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the SEM image of CeWOx@SiO2 wide temperature denitrification catalyst.

[0024] Figure 2 DeNOx performance of CeWOx@SiO2 catalyst.

[0025] Figure 3 Water-sulfur stability of CeWOx@SiO2 core-shell structure catalyst. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.

[0027] The denitration performance evaluation method of the catalyst of the present invention is as follows: simulate the exhaust gas composition, NO inlet concentration is 1000ppm, NH3 inlet concentration is 1000ppm, O2 content is 10%, SO2 inlet concentration is 300ppm (added when used), H2O content is 10vol.% (added when used), and N2 is used as carrier gas. The catalyst particle size is 40-60 mesh, and the reaction space velocity (GHSV) is set to 30000h -1The reaction temperature range is set to 100-550℃, and the flue gas analyzer is used to monitor NO online before and after the reaction. x concentration changes.

[0028] Embodiment 1:

[0029] (1)CeWO x Preparation of microspheres

[0030] According to the volume ratio of deionized water / anhydrous ethanol of 2:1, 40 ml of deionized water, 20 ml of anhydrous ethanol and 2.7 g of citric acid were measured and placed in the same container and stirred evenly to obtain a transparent and uniform solution A; according to the molar ratio of Ce and W elements of 1:0.2, 2.605 g of cerium nitrate and 0.149 g of ammonium metatungstate were weighed; the weighed cerium nitrate and ammonium metatungstate were added to solution A and stirred for 1 hour to obtain a mixed solution B; then solution B was transferred to a reactor and subjected to hydrothermal reaction at 180°C for 18 hours. The product after the reaction was washed with deionized water and anhydrous ethanol, dried at 80°C for 6 hours, and calcined at 500°C for 4 hours to obtain CeWO x Microspheres.

[0031] (2) Preparation of core-shell catalysts

[0032] Place 0.6g CeWO x Microspheres and 0.3 g hexadecyltrimethylammonium bromide were dispersed in 100 ml deionized water and ultrasonically treated for 30 min to obtain solution C. 0.3 ml ammonia water and 50 μl formic acid were added to solution C and stirred for 5 min to obtain solution D. 1 ml tetraethyl orthosilicate was added to solution D and stirred at 70 °C for 4 h. The product after the reaction was washed with deionized water and anhydrous ethanol, dried at 80 °C for 8 h, and calcined at 500 °C for 4 h to obtain CeWO. x @SiO2 wide temperature denitrification catalyst.

[0033] (3) Catalyst performance evaluation

[0034] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 180-550°C, and a denitration efficiency of 100% at 200-500°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate is 100%.

[0035] Embodiment 2:

[0036] (1)CeWO x Preparation of microspheres

[0037] Consistent with Example 1.

[0038] (2) Preparation of core-shell catalysts

[0039] Other conditions were the same as in Example 1, except that the reaction time after the addition of tetraethyl orthosilicate was changed from 4 h to 1 h.

[0040] (3) Catalyst performance evaluation

[0041] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 175-500°C, and a denitration efficiency of 100% at 200-450°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 88%.

[0042] Embodiment 3:

[0043] (1)CeWO x Preparation of microspheres

[0044] Consistent with Example 1.

[0045] (2) Preparation of core-shell catalysts

[0046] Other conditions were the same as in Example 1, except that the reaction time after the addition of tetraethyl orthosilicate was changed from 4 h to 6 h.

[0047] (3) Catalyst performance evaluation

[0048] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% at 225-550°C, a selectivity of N2 of more than 90%, and a denitration efficiency of 100% at 250-525°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 76%.

[0049] Embodiment 4:

[0050] (1)CeWO x Preparation of microspheres

[0051] Consistent with Example 1.

[0052] (2) Preparation of core-shell catalysts

[0053] Other conditions were the same as in Example 1, except that the reaction temperature was changed from 70°C to 50°C after tetraethyl orthosilicate was added.

[0054] (3) Catalyst performance evaluation

[0055] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 180-525°C, and a denitration efficiency of 100% at 200-475°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 73%.

[0056] Embodiment 5:

[0057] (1)CeWO x Preparation of microspheres

[0058] Consistent with Example 1.

[0059] (2) Preparation of core-shell catalysts

[0060] Other conditions were the same as in Example 1, except that the reaction temperature was changed from 70°C to 80°C after tetraethyl orthosilicate was added.

[0061] (3) Catalyst performance evaluation

[0062] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 225-550°C, and a denitration efficiency of 100% at 250-500°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 81%.

[0063] Embodiment 6:

[0064] (1)CeWO x Preparation of microspheres

[0065] Consistent with Example 1.

[0066] (2) Preparation of core-shell catalysts

[0067] Other conditions were the same as in Example 1, except that 0.2 ml of tetraethyl orthosilicate was added instead of 1 ml.

[0068] (3) Catalyst performance evaluation

[0069] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 175-500°C, and a denitration efficiency of 100% at 200-450°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 63%.

[0070] Embodiment 7:

[0071] (1)CeWO xPreparation of microspheres

[0072] Consistent with Example 1.

[0073] (2) Preparation of core-shell catalysts

[0074] Other conditions were the same as in Example 1, except that 2 ml of tetraethyl orthosilicate was added instead of 1 ml.

[0075] (3) Catalyst performance evaluation

[0076] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% at 250-550°C, a selectivity of N2 of more than 90%, and a denitration efficiency of 100% at 275-525°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 78%.

[0077] Embodiment 8:

[0078] (1)CeWO x Preparation of microspheres

[0079] Consistent with Example 1.

[0080] (2) Preparation of core-shell catalysts

[0081] Other conditions were the same as in Example 1, except that 20 μl of formic acid was added instead of 50 μl.

[0082] (3) Catalyst performance evaluation

[0083] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 180-525°C, and a denitration efficiency of 100% at 200-475°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 72%.

[0084] Embodiment 9:

[0085] (1)CeWO x Preparation of microspheres

[0086] Consistent with Example 1.

[0087] (2) Preparation of core-shell catalysts

[0088] The other conditions were the same as in Example 1, except that 100 μl of formic acid was added instead of 50 μl.

[0089] (3) Catalyst performance evaluation

[0090] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% within 200-525°C, and a denitration efficiency of 100% at 225-500°C. Under the condition of 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 75%.

[0091] Embodiment 10:

[0092] (1)CeWO x Preparation of microspheres

[0093] Consistent with Example 1.

[0094] (2) Preparation of core-shell catalysts

[0095] Other conditions were the same as in Example 1, except that the amount of ammonia added was changed from 0.3 ml to 0.1 ml.

[0096] (3) Catalyst performance evaluation

[0097] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 225-550°C, and a denitration efficiency of 100% at 250-500°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 86%.

[0098] Embodiment 11:

[0099] (1)CeWO x Preparation of microspheres

[0100] Consistent with Example 1.

[0101] (2) Preparation of core-shell catalysts

[0102] Other conditions were the same as in Example 1, except that 0.5 ml of ammonia water was added instead of 0.3 ml.

[0103] (3) Catalyst performance evaluation

[0104] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% within 200-525°C, and a denitration efficiency of 100% at 225-500°C. Under the condition of 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 70%.

[0105] Embodiment 12:

[0106] (1)CeWO xPreparation of microspheres

[0107] Consistent with Example 1.

[0108] (2) Preparation of core-shell catalysts

[0109] Other conditions were the same as in Example 1, except that 0.3 g of hexadecyltrimethylammonium bromide was added instead of 0.1 g.

[0110] (3) Catalyst performance evaluation

[0111] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 175-475°C, and a denitration efficiency of 100% at 180-425°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 52%.

[0112] Embodiment 13:

[0113] (1)CeWO x Preparation of microspheres

[0114] Consistent with Example 1.

[0115] (2) Preparation of core-shell catalysts

[0116] Other conditions were the same as in Example 1, except that 0.6 g of hexadecyltrimethylammonium bromide was added instead of 0.3 g.

[0117] (3) Catalyst performance evaluation

[0118] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% within 200-525°C, and a denitration efficiency of 100% at 225-500°C. Under the condition of 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 89%.

[0119] Embodiment 14:

[0120] (1)CeWO x Preparation of microspheres

[0121] Consistent with Example 1.

[0122] (2) Preparation of core-shell catalysts

[0123] Other conditions were the same as in Example 1, except that 0.6 g CeWO was added. x Microspheres were changed to 0.1g.

[0124] (3) Catalyst performance evaluation

[0125] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 200-550°C, and a denitration efficiency of 100% at 225-525°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 94%.

[0126] Embodiment 15:

[0127] (1)CeWO x Preparation of microspheres

[0128] Consistent with Example 1.

[0129] (2) Preparation of core-shell catalysts

[0130] Other conditions were the same as in Example 1, except that 0.6 g CeWO was added. x Microspheres were changed to 2.0g.

[0131] (3) Catalyst performance evaluation

[0132] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 180-500°C, and a denitration efficiency of 100% at 200-475°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 76%.

[0133] Embodiment 16:

[0134] (1)CeWO x Preparation of microspheres

[0135] Other conditions were the same as in Example 1, except that the calcination condition was changed from 500°C for 4 h to 600°C for 2 h.

[0136] (2) Preparation of core-shell catalysts

[0137] Consistent with Example 1.

[0138] (3) Catalyst performance evaluation

[0139] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 200-525°C, and a denitration efficiency of 100% at 225-475°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 82%.

[0140] Embodiment 17:

[0141] (1)CeWO x Preparation of microspheres

[0142] Consistent with Example 1.

[0143] (2) Preparation of core-shell catalysts

[0144] Other conditions were the same as in Example 1, except that the calcination condition was changed from 500°C for 4 h to 600°C for 2 h.

[0145] (3) Catalyst performance evaluation

[0146] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 225-525°C, and a denitration efficiency of 100% at 250-500°C. Under the condition of 225°C, water and sulfur were introduced for a long time to test the stability of water and sulfur resistance. After 12 hours of introduction of NO x The conversion rate was 93%.

[0147] Embodiment 18:

[0148] (1)CeWO x Preparation of microspheres

[0149] Other conditions were the same as in Example 1, except that the calcination condition was changed from 500°C for 4 h to 600°C for 2 h.

[0150] (2) Preparation of core-shell catalysts

[0151] Other conditions were the same as in Example 1, except that the calcination condition was changed from 500°C for 4 h to 600°C for 2 h.

[0152] (3) Catalyst performance evaluation

[0153] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% at 200-550°C, and a denitration efficiency of 100% at 225-500°C. At 225°C, water and sulfur were introduced for a long time to test the stability against water and sulfur. After 12 hours of introduction of NO x The conversion rate was 98%.

[0154] Comparative Example 1:

[0155] (1)CeWO x Preparation of microspheres

[0156] Other conditions are the same as in Example 1.

[0157] (2) Catalyst performance evaluation

[0158] The catalyst of the present invention has an efficiency of NH3-SCR removing NO of more than 90% and a selectivity of N2 of more than 90% within 175-450°C, and a denitration efficiency of 100% at 200-425°C. Under the condition of 225°C, water and sulfur were introduced for a long time to test the stability of water and sulfur resistance. After 12 hours of introduction of NO x The conversion rate was 42%.

[0159] Table 1 Example CeWO x @SiO2 catalyst denitrification performance greater than 90% temperature window and SiO2 shell thickness

[0160]

[0161]

Claims

1. A CeWO x @SiO2 wide temperature denitration catalyst, characterized by Preparation of CeWO by hydrothermal method x Microspheres are then deposited on CeWO x The surface of the microspheres is covered with a SiO2 shell.

2. A CeWO according to claim 1 x @The preparation method of SiO2 wide temperature denitration catalyst is characterized by: The preparation method of the catalyst is as follows: (1)CeWO x Preparation of microspheres The cerium salt and tungsten salt are dissolved in a mixture of water, ethanol and citric acid and mixed, and then a hydrothermal reaction is carried out. After the reaction, washing, drying and calcination are performed to obtain CeWO. x Microspheres; Wherein: the molar ratio of Ce to W element is 1:(0.01-0.5); preferably: the molar ratio of Ce to W element is 1:(0.2-0.5). (2) Preparation of core-shell catalysts Will CeWO x Microspheres and hexadecyltrimethylammonium bromide are dispersed in a solvent and mixed evenly. After mixing evenly, ammonia water and formic acid are added and stirred evenly to obtain a mixed solution. Then, tetraethyl orthosilicate is slowly added to the mixed solution for reaction. After the reaction is completed, washing, drying and calcination are performed in sequence to obtain CeWO. x @SiO2 wide temperature denitrification catalyst.

3. The preparation method according to claim 2, characterized in that: In the step (1), the hydrothermal reaction temperature is 150-180°C, the hydrothermal time is 15-24h; the drying temperature is 60-80°C, the drying time is 6-12h; the calcination temperature is 500-600°C, and the insulation time is 2-4h.

4. The preparation method according to claim 2, characterized in that: The citric acid in step (1) is a molding agent, and the mass ratio of water, ethanol and citric acid is 30-50:10-30:1-5.

5. The preparation method according to claim 2, characterized in that: In the step (1), the mass ratio of the salt to the mixed solution is 2-4:55-65, the salt is cerium salt and tungsten salt, and the mixture is water, ethanol and citric acid.

6. The preparation method according to claim 2, characterized in that: The hexadecyltrimethylammonium bromide (CTAB) described in step (2) is a surface modifier, ammonia water is a pH regulator, and formic acid is a hydrolysis inducer.

7. The preparation method according to claim 2, characterized in that: In step (2), CeWO x The mass ratio of the microsphere, hexadecyltrimethyl bromide and tetraethyl orthosilicate is 0.1-2:0.1-1:0.1-2.

8. The preparation method according to claim 2, characterized in that: In step (2), CeWO x The mass ratio of the micron ball to the ammonia water is 0.1-1:0.1-0.5, and the mass ratio of the ammonia water to the formic acid is 1-15:

1.

9. The preparation method according to claim 2, characterized in that: In step (2), the reaction temperature is 50-80°C, the reaction time is 1-6h; the drying temperature is 70-80°C, the drying time is 7-8h; the calcination temperature is 450-550°C, and the calcination time is 3-4h.

10. Use of the catalyst according to claim 1 as a denitration catalyst; preferably, the denitration temperature is 100 to 550°C.

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