CeWOx@SiO2 wide-temperature denitration catalyst, and preparation method and application thereof

Abstract

This invention provides a CeWOx@SiO2 wide-temperature denitration catalyst, its preparation method, and its application. The method involves preparing CeWOx@SiO2 via a hydrothermal process. x Microspheres are formed, and then a SiO2 shell is coated onto the catalyst surface via controlled hydrolysis, thereby widening the catalyst's active temperature window and improving its water and sulfur stability. The advantage of this invention lies in the controllable SiO2 shell thickness achieved through synergistic control of hydrolysis temperature, tetraethyl orthosilicate addition, and hydrolysis time. CeWO3 without SiO2 coating... x The catalyst maintains over 90% of its denitrification activity within a temperature range of 175-450℃, and CeWO3 prepared by encapsulating SiO2... x The SiO2 catalyst has a wider active temperature range, maintaining over 90% of its denitrification activity within the 180-550℃ temperature range, and its resistance to water and sulfur is significantly enhanced. It is suitable for flue gas denitrification in typical industries such as non-ferrous / chemical, steel, power, and cement.

Description

TECHNICAL FIELD

[0001] The present application relates to a novel wide-temperature, water-sulfur-resistant, low-temperature, high-efficiency core-shell structure denitration catalyst, belonging to the field of air pollution control technology and environmental protection catalyst materials. It is suitable for flue gas denitration in typical industries such as non-ferrous / chemical industry, steel, power, cement, etc. TECHNICAL BACKGROUND

[0002] It has been recognized that nitrogen oxides are major air pollutants, which not only directly endanger human health, but also are the main cause of haze, acid rain, and photochemical smog. At present, the widely used flue gas denitration technology is mainly selective catalytic reduction technology (SCR). V2O5-WO3 / TiO2 catalyst is one of the most commonly used commercial SCR denitration catalysts, with a temperature window of 300-400℃, and is widely used in power industry denitration. However, the flue gas conditions of non-electricity industry are complex, with low and fluctuating flue gas temperature, and containing water and sulfur, which makes it difficult for V2O5-WO3 / TiO2 catalyst to be applicable. With the proposal of the state to further reduce the total emission of NO x , the ultra-low emission of NO x from non-electricity industry flue gas has become a key issue. At present, constructing a core-shell structure catalyst based on the active components of SCR denitration catalyst is an effective strategy to improve its catalytic performance and water-sulfur stability. Patents such as (CN114653397A), (CN109529816A), (CN108176349A), and (CN102941083A) all enhance the catalytic performance and resistance to poisoning of the catalyst by constructing a core-shell structure. However, these catalysts often have a narrow denitration activity temperature window, and the preparation process is complex. Therefore, it is of great significance to develop a denitration catalyst with a simple preparation method, a wide temperature window, and strong stability. SUMMARY

[0003] The purpose of the present application is to develop a wide-temperature denitration catalyst, to solve the problems of narrow active temperature range, high cost, and poor water-sulfur poisoning resistance stability of existing denitration catalysts, and to provide a CeWO x @SiO2 wide-temperature denitration catalyst and a preparation method thereof.

[0004] The specific technical scheme of the present application is as follows:

[0005] A CeWO x @SiO2 wide-temperature denitration catalyst, which is prepared by a hydrothermal method to prepare CeWO x microspheres, and then wrapping SiO2 shell on the surface of the CeWO x microspheres.

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

[0007] (3) Preparation of CeWO x Preparation of microspheres

[0008] Dissolve the cerium salt and tungsten salt in a mixture of water, ethanol and citric acid, mix well, then perform a hydrothermal reaction, wash, dry and calcine after the reaction to obtain CeWO x microspheres;

[0009] The molar ratio of Ce and W elements is 1:(0.01-0.5); preferably, the molar ratio of Ce and W elements is 1:(0.2-0.5).

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

[0011] Dissolve the CeWO x microspheres and cetyltrimethylammonium bromide in a solvent and mix well, then add ammonia water and formic acid and stir well to obtain a mixture, then slowly add tetraethyl orthosilicate to the mixture to perform a reaction, then wash, dry and calcine in sequence after the reaction to obtain a CeWO x @SiO2 wide-temperature denitration catalyst.

[0012] In the above preparation method, the hydrothermal reaction temperature in step (1) 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 holding time is 2-4h.

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

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

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

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

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

[0018] In the above preparation method, the mass ratio of CeWO xThe mass ratio of the microspheres and the ammonia water is 0.1-1:0.1-0.5, and the mass ratio of the ammonia water and the formic acid is 1-15:1.

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

[0020] In the technical scheme, the catalyst is applied as a denitration catalyst, and preferably, the denitration temperature is 100-550 DEG C.

[0021] Beneficial effects:

[0022] The catalyst is suitable for NH3-SCR denitration under complex working conditions, and the denitration efficiency is greater than 90% and the N2 selectivity is greater than 95% in the temperature range of 180-550 DEG C; compared with the prior art, the catalyst system has a wider denitration activity temperature window and stronger water and sulfur stability. x The microspheres are prepared by a hydrothermal method, and a SiO2 shell layer is wrapped by controlling a hydrolysis method. The SiO2 shell layer thickness can be controlled by controlling the hydrolysis temperature, the addition amount of tetraethyl orthosilicate and the reaction time. Compared with the prior art denitration catalyst, the preparation method is simple and low in cost, and the prepared core-shell structure catalyst has a wide temperature window, excellent catalytic property and strong anti-poisoning capacity. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a SEM diagram of the CeWOx@SiO2 wide-temperature denitration catalyst.

[0024] Figure 2 It is the denitration performance of the CeWOx@SiO2 catalyst.

[0025] Figure 3 It is the water and sulfur stability of the CeWOx@SiO2 core-shell structure catalyst. DETAILED DESCRIPTION

[0026] The application will be further described below in combination with examples, but the protection scope of the application is not limited thereto.

[0027] The denitration performance evaluation method of the catalyst is as follows: the tail gas composition is simulated, the NO inlet concentration is 1000ppm, the NH3 inlet concentration is 1000ppm, the O2 content is 10%, the SO2 inlet concentration is 300ppm (added when used), the H2O content is 10vol.% (added when used), and N2 is used as the carrier gas. The catalyst particle size is 40-60 meshes, the reaction space velocity (GHSV) is set to 30000h-1, the reaction temperature is 150-550 DEG C, and the reaction pressure is 1-2MPa. -1, the reaction temperature range is set as 100-550℃, and a flue gas analyzer is used to monitor the concentration change of NO x before and after reaction.

[0028] Example 1

[0029] (1) Preparation of CeWO x microspheres

[0030] According to the volume ratio of deionized water / anhydrous ethanol of 2:1, 40ml of deionized water, 20ml of anhydrous ethanol and 2.7g of citric acid are measured and stirred uniformly in the same container to obtain a transparent and uniform solution A; according to the molar ratio of Ce and W elements of 1:0.2, 2.605g of cerium nitrate and 0.149g of ammonium metatungstate are weighed; the weighed cerium nitrate and ammonium metatungstate are added to the solution A, and the stirring is continued for 1h to obtain a mixed solution B; then the solution B is transferred to a reaction kettle for hydrothermal reaction at 180℃ for 18h, and the product after reaction is washed with deionized water and anhydrous ethanol, dried at 80℃ for 6h, and calcined at 500℃ for 4h to obtain CeWO x microspheres.

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

[0032] 0.6g of CeWO x microspheres and 0.3g of hexadecyl trimethyl ammonium bromide are dispersed in 100ml of deionized water, and ultrasonic treatment is performed for 30min to obtain a solution C; 0.3ml of ammonia water and 50μl of formic acid are added dropwise to the solution C, and stirring is performed for 5min to obtain a solution D; 1ml of tetraethyl orthosilicate is added dropwise to the solution D, and constant temperature stirring is performed at 70℃ for 4h; the product after reaction is washed with deionized water and anhydrous ethanol, dried at 80℃ for 8h, and calcined at 500℃ for 4h to obtain a CeWO x @SiO2 wide-temperature denitration catalyst.

[0033] (3) Catalyst performance evaluation

[0034] The catalyst of the present application has an NH3-SCR removal efficiency of NO of >90% within 180-550℃, an N2 selectivity of >90%, and a denitration efficiency of 100% within 200-500℃. Under the condition of 225℃, water and sulfur are simultaneously introduced for long time to test the water and sulfur stability, and after 12h, the NO x conversion rate is 100%.

[0035] Example 2

[0036] (1) Preparation of CeWO x microspheres

[0037] The same as example 1.

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

[0039] Other conditions are same as example 1, except that the reaction time after adding tetraethyl orthosilicate is changed from 4h to 1h.

[0040] (3) Catalyst performance evaluation

[0041] The catalyst of the present application has the efficiency of removing NO by NH3-SCR > 90% in 175-500℃, N2 selectivity > 90%, and the efficiency of denitration is 100% in 200-450℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO x conversion rate is 88%.

[0042] Example 3:

[0043] (1) CeWO x Preparation of microspheres

[0044] The same as example 1.

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

[0046] Other conditions are same as example 1, except that the reaction time after adding tetraethyl orthosilicate is changed from 4h to 6h.

[0047] (3) Catalyst performance evaluation

[0048] The catalyst of the present application has the efficiency of removing NO by NH3-SCR > 90% in 225-550℃, N2 selectivity > 90%, and the efficiency of denitration is 100% in 250-525℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO x conversion rate is 76%.

[0049] Example 4:

[0050] (1) CeWO x Preparation of microspheres

[0051] The same as example 1.

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

[0053] Other conditions are same as example 1, except that the reaction temperature after adding tetraethyl orthosilicate is changed from 70℃ to 50℃.

[0054] (3) Catalyst performance evaluation

[0055] The catalyst of the present application has the efficiency of removing NO by NH3-SCR of >90% within 180-525℃, the selectivity of N2 of >90%, and the efficiency of removing NO of 100% within 200-475℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 81% after passing in for 12h. x The conversion rate is 73%.

[0056] Example 5:

[0057] (1) CeWO x Preparation of microspheres

[0058] The same as Example 1.

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

[0060] The other conditions are the same as Example 1, except that the reaction temperature of 70℃ after adding tetraethyl orthosilicate is changed to 80℃.

[0061] (3) Catalyst performance evaluation

[0062] The catalyst of the present application has the efficiency of removing NO by NH3-SCR of >90% within 225-550℃, the selectivity of N2 of >90%, and the efficiency of removing NO of 100% within 250-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 81% after passing in for 12h. x The conversion rate is 81%.

[0063] Example 6:

[0064] (1) CeWO x Preparation of microspheres

[0065] The same as Example 1.

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

[0067] The other conditions are the same as Example 1, except that the addition of 1ml of tetraethyl orthosilicate is changed to 0.2ml.

[0068] (3) Catalyst performance evaluation

[0069] The catalyst of the present application has the efficiency of removing NO by NH3-SCR of >90% within 175-500℃, the selectivity of N2 of >90%, and the efficiency of removing NO of 100% within 200-450℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 63% after passing in for 12h. x The conversion rate is 63%.

[0070] Example 7:

[0071] (1) CeWO xPreparation of microspheres

[0072] The same as example 1.

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

[0074] The other conditions are the same as example 1, except that 1 ml of tetraethyl orthosilicate is added instead of 2 ml.

[0075] (3) Catalyst performance evaluation

[0076] The catalyst of the present application has an NH3-SCR removal efficiency of NO > 90% and N2 selectivity > 90% within 250-550℃, and a denitration efficiency of 100% within 275-525℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 78% after passing in for 12 h. x

[0077] Example 8:

[0078] (1) CeWO x Preparation of microspheres

[0079] The same as example 1.

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

[0081] The other conditions are the same as example 1, except that 50 μl of formic acid is added instead of 20 μl.

[0082] (3) Catalyst performance evaluation

[0083] The catalyst of the present application has an NH3-SCR removal efficiency of NO > 90% and N2 selectivity > 90% within 180-525℃, and a denitration efficiency of 100% within 200-475℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 72% after passing in for 12 h. x

[0084] Example 9:

[0085] (1) CeWO x Preparation of microspheres

[0086] The same as example 1.

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

[0088] The other conditions are the same as example 1, except that 50 μl of formic acid is added instead of 100 μl.

[0089] (3) Catalyst performance evaluation

[0090] ​​The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 200-525℃, and a de-NOx efficiency of 100% at 225-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO removal efficiency is 100% after passing in water and sulfur for 12h. x The conversion rate is 75%.

[0091] Example 10:

[0092] (1) CeWO x Preparation of microspheres

[0093] The same as Example 1.

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

[0095] The other conditions are the same as Example 1, except that 0.3ml of ammonia water is changed to 0.1ml.

[0096] (3) Catalyst performance evaluation

[0097] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 200-525℃, and a de-NOx efficiency of 100% at 225-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO removal efficiency is 100% after passing in water and sulfur for 12h. x The conversion rate is 86%.

[0098] Example 11:

[0099] (1) CeWO x Preparation of microspheres

[0100] The same as Example 1.

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

[0102] The other conditions are the same as Example 1, except that 0.3ml of ammonia water is changed to 0.5ml.

[0103] (3) Catalyst performance evaluation

[0104] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 200-525℃, and a de-NOx efficiency of 100% at 225-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO removal efficiency is 100% after passing in water and sulfur for 12h. x The conversion rate is 70%.

[0105] Example 12:

[0106] (1) CeWO xPreparation of microspheres

[0107] The same as example 1.

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

[0109] The other conditions are the same as example 1, except that 0.3 g of cetyltrimethylammonium bromide is replaced by 0.1 g.

[0110] (3) Catalyst performance evaluation

[0111] The catalyst of the present application has an NH3-SCR removal efficiency of NO > 90% and N2 selectivity > 90% within 175-475℃, and a denitration efficiency of 100% within 180-425℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 52% after passing in for 12 h. x

[0112] Example 13:

[0113] (1) CeWO x Preparation of microspheres

[0114] The same as example 1.

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

[0116] The other conditions are the same as example 1, except that 0.3 g of cetyltrimethylammonium bromide is replaced by 0.6 g.

[0117] (3) Catalyst performance evaluation

[0118] The catalyst of the present application has an NH3-SCR removal efficiency of NO > 90% and N2 selectivity > 90% within 200-525℃, and a denitration efficiency of 100% within 225-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 89% after passing in for 12 h. x

[0119] Example 14:

[0120] (1) CeWO x Preparation of microspheres

[0121] The same as example 1.

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

[0123] The other conditions are the same as example 1, except that 0.6 g of CeWO x microspheres is replaced by 0.1 g.

[0124] (3) Catalyst performance evaluation​​

[0125] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 200-550°C, and a de-NOx efficiency of 100% at 225-525°C. Under the condition of 225°C, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO removal efficiency is 100% after passing in for 12h. x The conversion rate is 94%.

[0126] Example 15:

[0127] (1) Preparation of CeWO x Preparation of microspheres

[0128] The same as Example 1.

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

[0130] The other conditions are the same as Example 1, except that 0.6g of CeWO x The microspheres are changed to 2.0g.

[0131] (3) Catalyst performance evaluation

[0132] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 180-500°C, and a de-NOx efficiency of 100% at 200-475°C. Under the condition of 225°C, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO removal efficiency is 100% after passing in for 12h. x The conversion rate is 76%.

[0133] Example 16:

[0134] (1) Preparation of CeWO x Preparation of microspheres

[0135] The other conditions are the same as Example 1, except that the calcination condition of 500°C for 4h is changed to 600°C for 2h.

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

[0137] The same as Example 1.

[0138] (3) Catalyst performance evaluation

[0139] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 200-525°C, and a de-NOx efficiency of 100% at 225-475°C. Under the condition of 225°C, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO removal efficiency is 100% after passing in for 12h. x The conversion rate is 82%.

[0140] Example 17:

[0141] (1)CeWO x Preparation of microspheres

[0142] The same as example 1.

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

[0144] The other conditions are the same as example 1, except that the calcination condition of 500℃ for 4h is changed to 600℃ for 2h.

[0145] (3) Catalyst performance evaluation

[0146] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 225-525℃, and a deNOx efficiency of 100% at 250-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 93% after passing in for 12h. x

[0147] Example 18:

[0148] (1)CeWO x Preparation of microspheres

[0149] The other conditions are the same as example 1, except that the calcination condition of 500℃ for 4h is changed to 600℃ for 2h.

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

[0151] The other conditions are the same as example 1, except that the calcination condition of 500℃ for 4h is changed to 600℃ for 2h.

[0152] (3) Catalyst performance evaluation

[0153] The catalyst of the present application has a NO removal efficiency of >90% and a N2 selectivity of >90% in NH3-SCR at 200-550℃, and a deNOx efficiency of 100% at 225-500℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO conversion rate is 98% after passing in for 12h. x

[0154] Comparative example 1:

[0155] (1)CeWO x Preparation of microspheres

[0156] The other conditions are the same as example 1.

[0157] (2) Catalyst performance evaluation

[0158] ​​The catalyst of the present application has the efficiency of removing NO by NH3-SCR of >90% within 175-450℃, N2 selectivity of >90%, and the efficiency of denitration of 100% within 200-425℃. Under the condition of 225℃, the water and sulfur resistance stability is tested by simultaneously passing in water and sulfur for a long time, and the NO x The conversion rate is 42%.

[0159] Table 1 Example CeWO x Temperature window and SiO2 shell thickness of the catalyst of the present application

[0160]

[0161]

Claims

1. A CeWO x The preparation method of the SiO2 wide-temperature denitration catalyst is characterized by: CeWO3 prepared by hydrothermal method x Microspheres, then in CeWO x The surface of the microspheres is encased in a SiO2 shell; The catalyst is prepared as follows: (1)CeWO x Preparation of microspheres Cerium salt and tungsten salt are dissolved in a mixture of water, ethanol, and citric acid and mixed thoroughly. A hydrothermal reaction is then carried out. After the reaction is complete, the mixture is washed, dried, and calcined to obtain CeWO3. x Microspheres; Wherein, the molar ratio of Ce to W is 1:(0.01~0.5); (2) Preparation of core-shell catalysts Will CeWO x Microspheres and hexadecyltrimethylammonium bromide were dispersed in a solvent and mixed thoroughly. Ammonia and formic acid were then added and stirred until homogeneous to obtain a mixed solution. Tetraethyl orthosilicate was then slowly added to the mixed solution to initiate the reaction. After the reaction was complete, the mixture was washed, dried, and calcined sequentially to obtain CeWO3. x @SiO2 wide-temperature denitration catalyst; In step (2), CeWO x The mass ratio of microspheres, hexadecyltrimethyl bromide, and tetraethyl orthosilicate is 0.1~2:0.1~1:0.1~2; the reaction temperature is 50~80℃, and the reaction time is 1~6h.

2. The preparation method according to claim 1, characterized in that, The molar ratio of Ce to W is 1:(0.2~0.5).

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

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

5. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of salt to mixture 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 1, characterized in that: In step (2), cetyltrimethylammonium bromide (CTAB) is used as a surface modifier, ammonia is used as a pH adjuster, and formic acid is used as a hydrolysis inducer.

7. The preparation method according to claim 1, characterized in that: CeWO in step (2) x The mass ratio of microspheres to ammonia is 0.1~1:0.1~0.5, and the mass ratio of ammonia to formic acid is 1~15:

1.

8. The preparation method according to claim 1, characterized in that: In step (2), the drying time is 7-8 hours; the calcination temperature is 450-550℃ and the calcination time is 3-4 hours.

9. The application of the catalyst prepared by the method of claim 1 in denitrification.

10. The application according to claim 9, characterized in that, The temperature for denitrification is 100~550℃.

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