A transition metal-based ammoxidation catalyst, its preparation method and use

Abstract

The present application relates to the technical field of ammonia oxidation catalyst, in particular to a transition metal-based ammonia oxidation catalyst and a preparation method and application thereof.The present application provides a transition metal-based ammonia oxidation catalyst, the ammonia oxidation catalyst comprises a carrier and an active component, the structural formula of the carrier is Ce a Sb b O2;wherein a=0.8-0.95, b=0.05-0.2.The transition metal-based ammonia oxidation catalyst provided by the present application can reach 80-100% ammonia conversion rate under the condition of 200-300 DEG C, and when copper is used as the active component, the nitrogen selectivity can reach more than 55% under the condition of 150-300 DEG C.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ammonia oxidation catalysts, in particular to a transition metal-based ammonia oxidation catalyst and a preparation method and application thereof. BACKGROUND

[0002] Among various gaseous pollutants, ammonia (NH3) as a colorless gas has a strong irritating odor, which can cause acid rain, photochemical smog and environmental problems. It also damages the human respiratory system and causes serious irritation to the skin and eyes. Among existing NH3 removal technologies, ammonia selective catalytic oxidation (NH3-SCO) stands out for its low cost and mild operating conditions, which selectively reduces NH3 in waste gas to N2 and H2O without polluting the environment through the action of a catalyst.

[0003] In the past few years, various types of catalysts have been reported, which are divided into noble metal-based materials and transition metal-based materials according to the composition of the active center of the catalyst. Noble metal-based catalysts have excellent ammonia oxidation performance at low temperature, and can achieve complete oxidation of NH3 above 150℃. At present, noble metal catalysts mainly load active components onto metal oxides or molecular sieves to achieve uniform dispersion of active components. Common carriers include Al2O3, TiO2, SiO2, SnO2, ZrO2, CeO2 and some molecular sieves such as ZSM-5, Y, SSZ, SAPO, etc., and common active components include Pt, Ag, Ru, Pd, etc. Although noble metals as active components generally make the catalyst have stronger oxidation performance, transition metals have lower catalytic activity than noble metals, but transition metals are abundant in nature and low in price, which are more suitable for commercialization. The catalytic performance of transition metal catalysts is affected by the type of precursor, loading amount, calcination temperature, surface type and reaction conditions, etc., and generally can achieve complete conversion of NH3 above 200℃, and common active components include Cu, Mn, Co, Fe, Ce, etc.

[0004] Ammonia oxidation catalysts need to have good catalytic activity, nitrogen selectivity, stability and low cost to have wide application, however, catalysts with sufficient activity, selectivity and stability under reaction conditions related to application are not yet available. Therefore, it is of important practical significance to research and develop a good transition metal-based ammonia oxidation catalyst with low temperature activity and high nitrogen selectivity. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a transition metal-based ammonia oxidation catalyst and a preparation method and application thereof, which can achieve ammonia conversion rate of 80-100% under the condition of 200-300℃, and nitrogen selectivity of more than 60% under the condition of 150-300℃.

[0006] To this end, the present application provides the following technical solutions,

[0007] In the first aspect, the present application provides, in optional embodiments, a transition metal-based ammoxidation catalyst, which comprises a carrier and an active component, the structural formula of the carrier is Ce a Sb b O2;

[0008] Wherein, a = 0.8-0.95, b = 0.05-0.2.

[0009] Preferably, the mass percentage of the active component is 5-20% based on the mass of the ammoxidation catalyst, and the rest is the carrier; the active component is a transition metal selected from one of copper, cobalt or manganese, preferably copper.

[0010] In the second aspect, the present application provides, in optional embodiments, a preparation method of the above-mentioned transition metal-based ammoxidation catalyst, comprising the following steps:

[0011] S1: dissolve cerium salt in water, then add ethylene glycol solution containing antimony salt and stir, then add citric acid, heat and stir to form a gel, and then dry and calcine to obtain a cerium-antimony oxide carrier;

[0012] S2: dissolve the cerium-antimony oxide carrier in water, then add an active component, stir, rotary evaporate, and calcine to obtain the ammoxidation catalyst;

[0013] Wherein, the molar ratio of the cerium salt and the antimony salt is 4-19.

[0014] Preferably, the cerium salt is selected from one or more of cerium nitrate or cerium chloride; the antimony salt is selected from one or more of antimony acetate or antimony nitrate. The addition amount of ethylene glycol is 10-20 ml, which is not limited in the present application as long as the antimony salt can be dissolved; the molar ratio of the citric acid and the metal ions in the solution after stirring is 1-1.5.

[0015] Preferably, in step S1, the heating and stirring time is 8-12 hours; the temperature is 80-100℃. The calcination time is 3-5 hours; the temperature is 400-600℃.

[0016] Preferably, in step S2, the rotary evaporation temperature is 65-80℃. The calcination time is 3-5 hours; the temperature is 300-500℃.

[0017] Preferably, the preparation method of the cerium-antimony oxide carrier can also be the following steps:

[0018] The cerium salt is dissolved in water, then the ethylene glycol solution containing antimony salt is added, stirred, settled, filtered, and the obtained precipitate is washed, dried, and calcined to obtain the cerium-antimony oxide carrier. The drying time is 8-12 hours, and the temperature is 100-120℃; the calcination time is 3-5 hours, and the temperature is 400-600℃. The stirring time is 3 hours.

[0019] In a third aspect, the application provides, in optional embodiments, the use of the transition metal-based ammoxidation catalyst or the transition metal-based ammoxidation catalyst prepared by the above method in the catalytic oxidation of ammonia into nitrogen and water.

[0020] Further, the transition metal-based ammoxidation catalyst is used for the selective catalytic oxidation of ammonia in diesel exhaust gas, and the conditions for treating ammonia in diesel exhaust gas are as follows: the temperature is 150-500℃, the concentration of ammonia in the exhaust gas is 500ppm, the volume fraction of oxygen is 10%, nitrogen is used as the balance gas, the gas flow rate is 300ml / min, and the amount of the selective ammoxidation catalyst used is 0.1-0.5ml.

[0021] Compared with the prior art, the application has one or more of the following beneficial effects:

[0022] 1. The conversion rate of ammonia of the transition metal-based ammoxidation catalyst provided by the application can reach 80-100% under the condition of 200-300℃, and the nitrogen selectivity can reach more than 60% when copper is used as the active component under the condition of 150-300℃.

[0023] 2. The transition metal-based ammoxidation catalyst provided by the application is green and environmentally friendly, and has low cost. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0025] Figure 1 The activity test results of the catalyst SCO prepared in Examples 1-7 and Comparative Examples 1-3 of the application are shown in the following figures.

[0026] Figure 2 The N2 selectivity results of the catalyst SCO prepared in Examples 1-7 and Comparative Examples 1-3 of the application are shown in the following figures. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with specific examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0028] In the specific embodiment of the present application, the structural formula of the carrier is Ce a Sb b O x ; wherein a = 0.8-0.95, b = 0.05-0.2, a can be 0.8, 0.85, 0.9, 0.95, and b can be 0.05, 0.1, 0.15, 0.2.

[0029] The cerium nitrate hexahydrate used in the present application is purchased from Tianjin Kemio Chemical Reagent Co., Ltd., AR pure; the antimony acetate is purchased from Tianjin Kemio Chemical Reagent Co., Ltd., AR pure; the citric acid is purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., AR pure; the copper nitrate trihydrate is purchased from Shanghai Maikelin Biochemical Technology Co., Ltd., AR pure; and the ethylene glycol is purchased from Kemate (Tianjin) Chemical Technology Co., Ltd., AR pure.

[0030] The present application will be described below with specific examples.

[0031] Example 1

[0032] The present embodiment provides a transition metal-based ammoxidation catalyst, which comprises a carrier and an active component, the structural formula of the carrier is Ce 0.95 Sb 0.05 O2, and the active component is copper.

[0033] The transition metal-based ammoxidation catalyst provided in the present embodiment is prepared by the following steps:

[0034] S1: 2.06g of the cerium nitrate hexahydrate precursor is weighed and dissolved in 10ml of deionized water to form a mixed solution A, and 0.07g of the antimony acetate precursor is weighed and dissolved in 10ml of ethylene glycol to form a mixed solution B; the mixed solution B is added to the mixed solution A, 1.37g of citric acid is added after stirring for 30min, and then transferred to a 90℃ oil bath pot for continuous stirring for 12h; the stirred gel-like sample is transferred to a 120℃ oven for drying for 12h; the sample is ground, and the powder-like sample is collected and placed in a muffle furnace for calcination under air atmosphere at 500℃ for 4h to obtain a CeSb oxide carrier;

[0035] S2: 2 g of the carrier was dissolved in 40 ml of deionized water, 0.29 g of copper nitrate precursor was added for impregnation, stirred for 3 h, and then rotary evaporated at 70°C, and the sample was scraped; the sample was placed in a muffle furnace and calcined at 400°C in air for 4 h to obtain the transition metal-based ammoxidation catalyst.

[0036] Example 2

[0037] The transition metal-based ammoxidation catalyst provided in this example comprises a carrier and an active component, and the structural formula of the carrier is Ce 0.9 Sb 0.1 O2, and the active component is copper.

[0038] The transition metal-based ammoxidation catalyst provided in this example is prepared by the following steps:

[0039] S1: 1.95 g of cerium nitrate hexahydrate precursor was dissolved in 10 ml of deionized water to form a mixed solution A, and 0.15 g of antimony acetate precursor was dissolved in 10 ml of ethylene glycol to form a mixed solution B; the mixed solution B was added to the mixed solution A, and 1.37 g of citric acid was added after stirring for 30 min, and then the mixture was transferred to a 90°C oil bath and stirred for 12 h; the stirred gel sample was transferred to a 120°C oven and dried for 12 h; the sample was ground, and the powder sample was collected and placed in a muffle furnace and calcined at 500°C in air for 4 h to obtain a CeSb oxide carrier;

[0040] S2: 2 g of the carrier was dissolved in 40 ml of deionized water, 0.29 g of copper nitrate precursor was added for impregnation, stirred for 3 h, and then rotary evaporated at 70°C, and the sample was scraped; the sample was placed in a muffle furnace and calcined at 400°C in air for 4 h to obtain the transition metal-based ammoxidation catalyst.

[0041] Example 3

[0042] The transition metal-based ammoxidation catalyst provided in this example comprises a carrier and an active component, and the structural formula of the carrier is Ce 0.85 Sb 0.15 O2, and the active component is copper.

[0043] The transition metal-based ammoxidation catalyst provided in this example is prepared by the following steps:

[0044] S1: 1.85 g of cerium nitrate hexahydrate precursor was weighed and dissolved in 10 ml of deionized water to form a mixed solution A, and 0.22 g of antimony acetate precursor was weighed and dissolved in 10 ml of ethylene glycol to form a mixed solution B; the mixed solution B was added to the mixed solution A, 1.37 g of citric acid was added after stirring for 30 min, and the stirring was continued in a 90℃ oil bath pot for 12 h; the stirred gel sample was transferred to a 120℃ oven for drying for 12 h; the sample was ground, and the powdered sample was placed in a muffle furnace and calcined at 500℃ in air for 4 h to obtain a CeSb oxide carrier;

[0045] S2: 2 g of the above carrier was dissolved in 40 ml of deionized water, impregnated with 0.29 g of copper nitrate precursor, stirred for 3 h, and rotary evaporated at 70℃, and the sample was scraped; the sample was placed in a muffle furnace and calcined at 400℃ in air for 4 h to obtain a transition metal-based ammoxidation catalyst.

[0046] Example 4

[0047] The example provides a transition metal-based ammoxidation catalyst, which comprises a carrier and an active component, and the structural formula of the carrier in terms of atomic ratio is Ce 0.8 Sb 0.2 O2, and the active component is copper.

[0048] The transition metal-based ammoxidation catalyst provided by the example is prepared by the following steps:

[0049] S1: 1.74 g of cerium nitrate hexahydrate precursor was weighed and dissolved in 10 ml of deionized water to form a mixed solution A, and 0.30 g of antimony acetate precursor was weighed and dissolved in 10 ml of ethylene glycol to form a mixed solution B; the mixed solution B was added to the mixed solution A, 1.37 g of citric acid was added after stirring for 30 min, and the stirring was continued in a 90℃ oil bath pot for 12 h; the stirred gel sample was transferred to a 120℃ oven for drying for 12 h; the sample was ground, and the powdered sample was placed in a muffle furnace and calcined at 500℃ in air for 4 h to obtain a CeSb oxide carrier;

[0050] S2: 2 g of the above carrier was dissolved in 40 ml of deionized water, impregnated with 0.29 g of copper nitrate precursor, stirred for 3 h, and rotary evaporated at 70℃, and the sample was scraped; the sample was placed in a muffle furnace and calcined at 400℃ in air for 4 h to obtain a transition metal-based ammoxidation catalyst.

[0051] Example 5

[0052] The example provides a transition metal-based ammoxidation catalyst, which comprises a carrier and an active component, and the structural formula of the carrier in terms of atomic ratio is Ce 0.9 Sb 0.1O2, the active component is copper.

[0053] The transition metal-based ammoxidation catalyst provided in this embodiment is prepared by the following steps:

[0054] S1: 1.95 g of cerium nitrate hexahydrate precursor was dissolved in 10 ml of deionized water to form a mixed solution A. 0.15 g of antimony acetate precursor was dissolved in 10 ml of ethylene glycol to form a mixed solution B. The mixed solution B was added to the mixed solution A, stirred for 30 min, and then 1.37 g of citric acid was added. The mixture was transferred to a 90°C oil bath and stirred for 12 h. The stirred gel sample was transferred to a 120°C oven and dried for 12 h. The sample was ground and the powdered sample was collected and placed in a muffle furnace. The powdered sample was calcined at 500°C in air atmosphere for 4 h to obtain a CeSb oxide support.

[0055] S2: Dissolve 2 g of the above-mentioned carrier in 40 ml of deionized water, add 0.59 g of copper nitrate precursor for impregnation, stir for 3 h, and then rotary evaporate at 70°C to scrape out the sample; place the above-mentioned sample in a muffle furnace and calcine it at 400°C in air atmosphere for 4 h to obtain a transition metal-based ammonia oxidation catalyst.

[0056] Example 6

[0057] This embodiment provides a transition metal-based ammoxidation catalyst, including a carrier and an active component. In terms of atomic ratio, the structural formula of the carrier is Ce: 0.9 Sb 0.1 O2, the active component is cobalt.

[0058] The transition metal-based ammoxidation catalyst provided in this embodiment is prepared by the following steps:

[0059] S1: 1.95 g of cerium nitrate hexahydrate precursor was dissolved in 10 ml of deionized water to form a mixed solution A. 0.15 g of antimony acetate precursor was dissolved in 10 ml of ethylene glycol to form a mixed solution B. The mixed solution B was added to the mixed solution A, stirred for 30 min, and then 1.37 g of citric acid was added. The mixture was transferred to a 90°C oil bath and stirred for 12 h. The stirred gel sample was transferred to a 120°C oven and dried for 12 h. The sample was ground and the powdered sample was collected and placed in a muffle furnace. The powdered sample was calcined at 500°C in air atmosphere for 4 h to obtain a CeSb oxide support.

[0060] S2: Dissolve 2 g of the above-mentioned carrier in 40 ml of deionized water, add 0.31 g of cobalt nitrate precursor for impregnation, stir for 3 h, and then rotary evaporate at 70°C to scrape out the sample; place the above-mentioned sample in a muffle furnace and calcine it at 400°C in air atmosphere for 4 h to obtain a transition metal-based ammonia oxidation catalyst.

[0061] Example 7

[0062] The embodiment provides a transition metal-based ammoxidation catalyst, which comprises a carrier and an active component, the structural formula of the carrier is Ce 0.9 Sb 0.1 O2, and the active component is manganese.

[0063] The transition metal-based ammoxidation catalyst provided by the embodiment is prepared through the following steps.

[0064] S1: 1.95 g of cerium nitrate hexahydrate precursor is dissolved in 10 ml of deionized water to form a mixed solution A, and 0.15 g of antimony acetate precursor is dissolved in 10 ml of ethylene glycol to form a mixed solution B; the mixed solution B is added to the mixed solution A, 1.37 g of citric acid is added after stirring for 30 min, and the stirring is continued in a 90 DEG C oil bath for 12 h; the stirred gel sample is transferred to a 120 DEG C oven for drying for 12 h; the sample is ground, and the powdered sample is collected and placed in a muffle furnace for calcination under an air atmosphere at 500 DEG C for 4 h, to obtain a CeSb oxide carrier.

[0065] S2: 2 g of the carrier is dissolved in 40 ml of deionized water, 0.33 g of manganese nitrate precursor is impregnated, stirring is performed for 3 h, and then 70 DEG C rotary evaporation is performed, and the sample is scraped; the sample is placed in a muffle furnace and calcined under an air atmosphere at 400 DEG C for 4 h, to obtain a transition metal-based ammoxidation catalyst.

[0066] Comparative Example 1

[0067] The comparative example provides a transition metal-based ammoxidation catalyst, which comprises a carrier and an active component, the carrier is CeO2 in terms of atomic ratio, and the active component is copper.

[0068] The transition metal-based ammoxidation catalyst provided by the comparative example is prepared through the following steps.

[0069] S1: 2.17 g of cerium nitrate hexahydrate precursor is dissolved in 20 ml of deionized water to form a mixed solution, 1.37 g of citric acid is added after stirring for 30 min, and the stirring is continued in a 90 DEG C oil bath for 12 h; the stirred gel sample is transferred to a 120 DEG C oven for drying for 12 h; the sample is ground, and the powdered sample is collected and placed in a muffle furnace for calcination under an air atmosphere at 500 DEG C for 4 h, to obtain a CeO2 oxide carrier.

[0070] S2: 2 g of the carrier is dissolved in 40 ml of deionized water, 0.29 g of copper nitrate precursor is impregnated, stirring is performed for 3 h, and then 70 DEG C rotary evaporation is performed, and the sample is scraped; the sample is placed in a muffle furnace and calcined under an air atmosphere at 400 DEG C for 4 h, to obtain an ammoxidation catalyst.

[0071] Comparative Example 2

[0072] This comparative example provides a transition metal-based ammoxidation catalyst, which comprises a support and an active component, the support is Sb2O4 and the active component is copper in terms of atomic ratio.

[0073] This comparative example provides a transition metal-based ammoxidation catalyst, which is prepared by the following steps:

[0074] S1: 1.49 g of antimony acetate precursor is dissolved in 20 ml of ethylene glycol to form a mixed solution, 1.37 g of citric acid is added after stirring for 30 min, and then it is transferred to a 90°C oil bath pot for continuous stirring for 12 h; the above stirred gel-like sample is transferred to a 120°C oven for drying for 12 h; the sample is ground, and the powdered sample is placed in a muffle furnace for calcination under air atmosphere at 500°C for 4 h to obtain an Sb2O3 oxide support.

[0075] S2: 2 g of the above support is dissolved in 40 ml of deionized water, 0.29 g of copper nitrate precursor is impregnated, and stirring is performed for 3 h, then rotary evaporation is performed at 70°C, and the sample is scraped; the above sample is placed in a muffle furnace for calcination under air atmosphere at 400°C for 4 h to obtain an ammoxidation catalyst.

[0076] Comparative Example 3

[0077] This comparative example provides a transition metal-based ammoxidation catalyst, which is prepared by the following steps:

[0078] S1: 1.95 g of cerium nitrate hexahydrate precursor is dissolved in 10 ml of deionized water to form a mixed solution A, 0.29 g of copper nitrate precursor is dissolved in 10 ml of deionized water to form a mixed solution B, and 0.15 g of antimony acetate precursor is dissolved in 10 ml of ethylene glycol to form a mixed solution C; the mixed solutions C, B are added to the mixed solution A, 1.37 g of citric acid is added after stirring for 30 min, and then it is transferred to a 90°C oil bath pot for continuous stirring for 12 h; the above stirred gel-like sample is transferred to a 120°C oven for drying for 12 h; the sample is ground, and the powdered sample is placed in a muffle furnace for calcination under air atmosphere at 500°C for 4 h to obtain a CuCe 0.9 Sb 0.1 O2 ammoxidation catalyst.

[0079] Test Example

[0080] The selective ammoxidation catalysts obtained in Examples 1-7 and Comparative Examples 1-3 are added to a quartz tube, and a simulated diesel vehicle exhaust reaction is carried out, the composition of the simulated diesel vehicle exhaust is 500 ppm of NH3 and 10% by volume of O2, the balance is N2, the total flow rate is 300 ml / min, and the space velocity is 100000 h -1The conversion rate of NH3 and the selectivity of N2 of the catalysts of the examples and the comparative examples were detected at 200-300 DEG C and 150-300 DEG C respectively, and the results were shown in Table 1 and Table 2. Figures 1-2 and Table 1 and Table 2:

[0081] The conversion rate of NH3 was calculated by the formula: (NH3 concentration at the inlet of the reactor-NH3 concentration at the outlet of the reactor) / (NH3 concentration at the inlet of the reactor) x 100 %.

[0082] The selectivity of N2 was calculated by the formula: (NH3 concentration at the inlet of the reactor-NH3 concentration at the outlet of the reactor-NO concentration at the outlet of the reactor-NO2 concentration at the outlet of the reactor-N2O concentration at the outlet of the reactor) / (NH3 concentration at the inlet of the reactor-NH3 concentration at the outlet of the reactor) x 100 %.

[0083] Table 1 Conversion rate of NH3 of the catalysts of the examples and the comparative examples at 200-280 DEG C

[0084]

[0085] Table 2 Selectivity of N2 of the catalysts of the examples and the comparative examples at 150-300 DEG C

[0086]

[0087]

[0088] From Table 1, 2 and Figure 1 , 2 It can be seen that the catalysts of the present application have good low-temperature activity, and the conversion rate of NH3 of the catalysts of the examples is higher than 90 % at 220 DEG C, which is difficult to achieve by the same catalysts. The catalysts of the comparative examples 2 and 3 have high selectivity of N2, but low conversion rate of NH3, and the catalyst of the comparative example 1 has high conversion rate of NH3, but low selectivity of N2. Therefore, the ammonia oxidation catalyst prepared by the method of the present application has good low-temperature catalytic performance, low cost and high cost performance.

[0089] Although the principle of the present application has been described in detail in combination with the preferred embodiments of the present application, those skilled in the art should understand that the above embodiments are only illustrative implementation of the present application, and do not limit the scope of the present application. The details in the embodiments do not constitute a limitation on the scope of the present application. Any equivalent transformation, simple replacement, etc. based on the technical solutions of the present application, without departing from the spirit and scope of the present application, falls within the scope of the present application.

Claims

1. A transition metal-based ammonia oxidation catalyst for catalytic oxidation of ammonia to nitrogen and water, characterized in that: The ammonia oxidation catalyst comprises a carrier and an active component. In terms of atomic ratio, the structural formula of the carrier is Ce a Sb b O2; where a=0.8-0.95, b=0.05-0.2; Based on the mass of the ammonia oxidation catalyst, the mass percentage of the active component is 5-20%, and the rest is the carrier; the active component is a transition metal, and the transition metal is selected from one of copper, cobalt or manganese; The preparation method of the transition metal-based ammoxidation catalyst comprises the following steps: S1: After dissolving the cerium salt in water, add the ethylene glycol solution containing the antimony salt and stir, then add citric acid, heat and stir to form a gel, then dry and calcine to obtain a cerium antimony oxide support; S2: dissolving the cerium antimony oxide support in water, adding active components, stirring, rotary evaporation, and calcining to obtain the ammonia oxidation catalyst; Wherein, the molar ratio of the cerium salt to the antimony salt is 4-19.

2. The use according to claim 1, characterized in that The cerium salt is selected from one or more of cerium nitrate and cerium chloride; and / or, The antimony salt is selected from one or more of antimony acetate and antimony nitrate.

3. The use according to claim 1, characterized in that The molar ratio of the citric acid to the metal ions in the stirred solution is 1-1.

5.

4. The use according to claim 1, characterized in that In step S1, the heating and stirring time is 8-12 hours and the temperature is 80-100°C; and / or, The calcination time is 3-5 hours and the temperature is 400-600°C.

5. The use according to claim 1, characterized in that In step S2, the rotary evaporation temperature is 65-80°C; The calcination time is 3-5 hours and the temperature is 300-500°C.

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