CN112717990A - Cu-SSZ-13@ Fe with core-shell structurexOyCatalyst and preparation method thereof - Google Patents

Cu-SSZ-13@ Fe with core-shell structurexOyCatalyst and preparation method thereof Download PDF

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CN112717990A
CN112717990A CN202011601816.1A CN202011601816A CN112717990A CN 112717990 A CN112717990 A CN 112717990A CN 202011601816 A CN202011601816 A CN 202011601816A CN 112717990 A CN112717990 A CN 112717990A
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ssz
catalyst
stirring
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shell structure
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谢利娟
王逸娇
刘畅
邓芸
缪恒锋
阮文权
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Jiangnan University
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    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
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Abstract

The invention discloses Cu-SSZ-13@ Fe with a core-shell structurexOyA catalyst and a preparation method thereof, belonging to the technical field of catalyst preparation. According to the method, CTAB is taken as a template agent, Fe metal elements are introduced through a specific self-assembly process to uniformly wrap Cu-SSZ-13 to form Cu-SSZ-13@ Fe with a core-shell structurexOyA catalyst. The obtained Cu-SSZ-13@ Fe with a core-shell structurexOyCatalyst for obviously reducing SO2‑H2Influence of O, reduction of catalyst activity during water sulfur poisoningThe loss of activity is reduced, the water-sulfur poisoning degree of the catalyst is reduced, and the low-temperature catalytic activity of the catalyst after the water-sulfur poisoning is improved.

Description

Cu-SSZ-13@ Fe with core-shell structurexOyCatalyst and preparation method thereof
Technical Field
The invention relates to Cu-SSZ-13@ Fe with a core-shell structurexOyA catalyst and a preparation method thereof, belonging to the technical field of catalyst preparation.
Background
According to annual environmental protection release annual Chinese moving source environmental management (2019), it is shown that by 2019, the number of motor vehicles in China reaches 3.48 hundred million, wherein the number of the vehicles reaches 2.6 million, and the number of new energy vehicles with very small emission only accounts for 1.5%. In 2019, the emission amounts of CO, HC, NOx and PM of automobiles are 694.44 ten thousand tons, 171.226 ten thousand tons, 622.252 ten thousand tons and 6.8968 ten thousand tons respectively. Respectively account for 90%, 90.5%, 97.9% and 93.2% of the total emission, and account for a huge proportion in the emission of pollutants of the motor vehicle. According to the annual report of national mobile sources in the past, the tail gas emission of diesel vehicles contributes most of NOx and PM pollutants, in order to further control the emission of motor vehicle pollutants, national VI regulations are implemented in 2019 in partial areas of China, the emission limit of each pollutant is required to be greatly tightened, and the NOx is reduced from 2000mg/kwh at the current stage of the national V to 460mg/kwh at the stage of the national VI. Therefore, the Cu-SSZ-13 molecular sieve catalyst with excellent NH3-SCR catalytic performance and good hydrothermal stability becomes the primary choice of the diesel vehicle SCR catalyst.
SSZ-13 molecular sieves having the Chabazite (CHA) structure and made of AlO4And SiO4The tetrahedra are connected end to end through oxygen atoms and are orderly arranged into ellipsoidal cages (0.73nm multiplied by 1.2nm) with eight-membered ring structures and three-dimensional cross-channel structure channels, and the tetrahedra have more surface proton acid centers and exchangeable cations, and the specific surface area of the tetrahedra can reach 700m2(ii) in terms of/g. Cu-SSZ-13 catalyst has excellent NH3SCR catalytic performance and hydrothermal stability, already in commercial use in state VI.
With the tightening of motor vehicle exhaust emission regulations and the increase of engine efficiency, especially in the case of cold start, the exhaust gas after-treatment systemThe low temperature activity of (b) puts higher demands. At present, the requirement of national VI standard on the sulfur content of diesel oil products is not more than 10mg/kg, the quality of the diesel oil products in different areas of China is uneven, the sulfur content of the diesel oil cannot completely meet the standard of national VI diesel oil, and an exhaust gas post-treatment system of a diesel motor vehicle often contains SO2In the environment of (2). Trace SO in tail gas of diesel vehicle2Can poison Cu-SSZ-13 molecular sieve catalysts, especially in SO2The synergistic effect of the sulfur and water vapor in the presence of the sulfur increases the degree of Cu-SSZ-13 sulfur poisoning, resulting in NH3The low-temperature (150-250 ℃) activity of SCR is greatly reduced. Therefore, it is necessary to improve the water and sulfur poisoning resistance of the Cu-SSZ-13 molecular sieve catalyst.
Disclosure of Invention
The technical problem is as follows: the invention aims to solve and supplement the problems of easy sulfur poisoning and low-temperature catalytic activity of the catalyst in the prior art, and provides a novel Cu-SSZ-13@ Fe core-shell structurexOyCatalyst and preparation method thereof, and method for improving catalyst in NH3Resistance to water-sulfur poisoning in SCR applications.
The technical scheme is as follows:
preparation of Cu-SSZ-13@ Fe with core-shell structurexOyA process for the preparation of a catalyst comprising the steps of:
(1) dispersing a copper salt in water to prepare a copper salt aqueous solution, then adding an H-SSZ-13 molecular sieve to perform hydrothermal reaction, after the reaction is finished, performing solid-liquid separation, collecting solids, drying and roasting to obtain Cu-SSZ-13;
(2) dispersing the obtained Cu-SSZ-13 and CTAB in absolute ethyl alcohol, and uniformly mixing to obtain a mixed solution; dispersing iron salt and hexamethylenetetramine in water to prepare an iron salt aqueous solution;
(3) mixing the obtained mixed solution with an iron salt aqueous solution, then heating and refluxing for reaction, after the reaction is finished, carrying out solid-liquid separation, collecting solids, drying and roasting to obtain Cu-SSZ-13@ Fe with a core-shell structurexOyA catalyst.
In one embodiment of the present invention, the copper salt in step (1) is selected from copper sulfate pentahydrate, copper sulfate, copper chloride, and copper nitrate.
In one embodiment of the present invention, in the step (1), Cu is in the copper salt aqueous solution2+The concentration of (A) is 0.005-0.01 mol/L; preferably 0.007 mol/L.
In one embodiment of the invention, the mass ratio of the copper salt to the H-SSZ-13 molecular sieve in the step (1) is (0.1-0.2): 1; preferably 0.1755: 1.
in one embodiment of the present invention, the temperature of the hydrothermal reaction in the step (1) is 80-100 ℃; the time is 1-5 h.
In one embodiment of the present invention, the calcination conditions in the step (1) are as follows: roasting at 600-650 ℃ for 5-6 h.
In one embodiment of the invention, the mass ratio of CTAB to Cu-SSZ-13 in the step (2) is (2-0.1): 1. preferably, the ratio of 2: 1.
in one embodiment of the present invention, the CTAB is added in the step (2) in an amount of (0.05g-1g)/500mL of absolute ethanol.
In one embodiment of the present invention, the iron salt in the step (2) is selected from iron nitrate nonahydrate, iron nitrate, iron chloride, and iron sulfate.
In one embodiment of the invention, the mass ratio of the iron salt to the Cu-SSZ-13 in the step (2) is (0.03-0.1): 1. preferably (0.035-0.185): 1.
in one embodiment of the present invention, Fe is contained in the iron salt aqueous solution in the step (2)3+The concentration of (A) is 0.0002-0.0012 mol/L; preferably 0.0003 to 0.0004 mol/L.
In one embodiment of the present invention, the molar ratio of hexamethylenetetramine to iron salt in step (2) is 5: 1.
In one embodiment of the present invention, the volume ratio of the mixed solution to the iron salt aqueous solution in the step (3) is 6: 4.
in one embodiment of the present invention, the firing conditions in the step (3) are as follows: roasting at 600-650 ℃ for 5-6 h.
In one embodiment of the invention, a core-shell structure Cu-SSZ-13@ Fe is preparedxOyMethod for preparing catalystThe method specifically comprises the following steps:
1) mixing copper sulfate pentahydrate and deionized water, stirring and dissolving to obtain CuSO4Adding an H-SSZ-13 molecular sieve into the aqueous solution, stirring for a period of time at a certain temperature, and then carrying out suction filtration, washing, drying and roasting to obtain Cu-SSZ-13 powder;
2) adding a certain amount of absolute ethyl alcohol into Cu-SSZ-13 powder, uniformly stirring, adding a certain amount of CTAB, stirring and ultrasonically dispersing uniformly; mixing a certain amount of ferric nitrate nonahydrate with deionized water, stirring and dissolving to obtain Fe (NO)3)3The solution is then added with a certain amount of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), and stirring uniformly;
3) mixing the absolute ethyl alcohol mixed solution in the step 2) with the aqueous solution (volume ratio absolute ethyl alcohol: H)2O ═ 6: 4); placing the mixed solution in a flask, heating in a water bath at a certain temperature, refluxing for a period of time, standing for a period of time, performing suction filtration, washing with ethanol and water for multiple times, drying, and roasting to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
The invention also provides the Cu-SSZ-13@ Fe with the core-shell structure prepared by the methodxOyA catalyst.
In one embodiment of the invention, the Cu-SSZ-13@ FexOyIn the catalyst, the Cu content is 2.0 wt.% to 2.5 wt.%, the Fe content is 0.5 wt.% to 2.5 wt.%; the Fe content is preferably 0.75 wt.% to 1.25 wt.%.
The invention also provides the Cu-SSZ-13@ Fe with the core-shell structurexOyCatalyst in NH3SCR catalytic reaction, automobile exhaust treatment.
The invention has the beneficial effects that:
the invention prepares Cu-SSZ-13@ Fe with a core-shell structurexOyThe method of the catalyst takes CTAB as a template agent, and introduces Fe metal element with good water and sulfur poisoning resistance through a self-assembly method to uniformly wrap Cu-SSZ-13 to form a Fe film core-shell structure, which is remarkable in thatThe loss of catalytic activity in the process of water sulfur poisoning of the catalyst is reduced, the sulfur poisoning degree of the catalyst is reduced, and the low-temperature (150 ℃ C. and 250 ℃ C.) catalytic activity of the catalyst after sulfur poisoning is improved.
Cu-SSZ-13@ Fe prepared by the inventionxOyApplication of catalyst to NH3-SCR catalyzed reaction Cu-SSZ-13@ Fe after water sulfur poisoningxOyCompared with a Cu-SSZ-13 catalyst poisoned by water and sulfur, the catalyst has improved low-temperature (150 ℃ C. and 250 ℃ C.) catalytic activity. Wherein the catalytic activity at 250 ℃ is improved to the maximum to catalyze NH3The conversion of SCR can reach 65.39%, which is 32.3% higher than that of the unmodified catalyst in comparative example 1, and 27.4% higher than that of the simple Fe-doped modified catalyst in comparative example 2.
Drawings
FIG. 1 shows the core-shell structure Cu-SSZ-13@ Fe obtained in example 2xOyTransmission electron micrograph of catalyst.
FIG. 2 is a transmission electron micrograph of the Cu-SSZ-13 catalyst obtained in comparative example 1.
Detailed Description
The present invention will be further described with reference to the following specific examples.
Example 1
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 1g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0181g Fe (NO) is weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3Solution, then 0.0314g hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring thoroughly untilDissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain Cu-SSZ-13@ FexOyA catalyst powder.
Example 2
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 1g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0273g Fe (NO) was weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.0473g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
Determination of the resulting Cu-SSZ-13@ FexOyThe transmission electron microscope image of the catalyst is shown in FIG. 1, and the catalyst has a core-shell structure, and the surface of Cu-SSZ-13 powder is provided with an iron thin layer.
Example 3
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 1g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0364g Fe (NO) were weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.0632g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
Example 4
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 1g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0457g of Fe (NO) is weighed3)3·9H2Adding 200mL of deionized water into the O solution for mixingStirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.0792g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
Example 5
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 1g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0549g Fe (NO) were weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.0953g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
Example 6
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 1g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0925g Fe (NO) was weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.1605g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
Example 7
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 0.25g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0273g Fe (NO) was weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.0473g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution into a flask, heating in a water bath at 75 ℃, refluxing for 2h, standing for 12h, performing suction filtration, washing with ethanol and deionized water for multiple times to remove the template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structure Cu-SSZ-13@ FexOyA catalyst powder.
Example 8
1) 0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
2) adding 0.5g of Cu-SSZ-13 powder into 300mL of absolute ethyl alcohol, stirring for 10min, adding 0.05g of CTAB, stirring for 10min, and performing ultrasonic treatment for 30min to uniformly disperse;
3) 0.0273g Fe (NO) was weighed out3)3·9H2Adding 200mL of deionized water into O for mixing, stirring and dissolving to obtain Fe (NO)3)3The solution was then charged with 0.0473g of hexamethylenetetramine (molar ratio Fe (NO)3)3:C6H12N41:5), stirring fully until dissolving;
4) mixing the absolute ethyl alcohol mixed solution obtained in the step 2) and the step 3) with an aqueous solution (volume ratio: absolute ethyl alcohol: H)2O6: 4), stirring for 10min to homogenize. Placing the mixed solution in a flask, heating in 75 ℃ water bath, refluxing for 2h, standing for 12h, filtering, washing with ethanol and deionized water for multiple times to remove template agent, drying at 105 ℃ for 12h, and roasting at 600 ℃ at a heating rate of 1 ℃/min for 6h to obtain the core-shell structureCu-SSZ-13@FexOyA catalyst powder.
Comparative example 1
0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain the Cu-SSZ-13 catalyst.
The transmission electron micrograph of the resulting Cu-SSZ-13 catalyst was determined and is shown in FIG. 2.
Comparative example 2
Constructing a Fe-doped catalyst Fe-Cu-SSZ-13 without a core-shell structure:
0.1755g of CuSO is taken4·5H2Adding O into 100mL of deionized water, stirring and dissolving to obtain CuSO4Adding a 1g H-SSZ-13 molecular sieve into the aqueous solution, stirring the mixture for 1h in a water bath at the temperature of 80 ℃, then performing suction filtration and washing for multiple times, drying the mixture for 12h at the temperature of 105 ℃, and roasting the dried mixture for 6h at the temperature rise rate of 1 ℃/min and the temperature of 600 ℃ to obtain Cu-SSZ-13 powder;
0.0273g Fe (NO) was weighed out3)3·9H2Adding O into 500mL of deionized water, stirring and dissolving to obtain Fe (NO)3)3And adding 50mg of urea and 0.5g of Cu-SSZ-13 powder into the solution, stirring the solution in a water bath at 90 ℃ for 12 hours, then carrying out suction filtration, washing and washing the solution for multiple times to remove residual urea, drying the solution at 105 ℃ for 12 hours, and roasting the solution at 600 ℃ at the heating rate of 1 ℃/min for 6 hours to obtain the Fe-Cu-SSZ-13 catalyst.
And (3) performance measurement:
the catalysts prepared in examples 1 to 8 and comparative example 1 were measured for their contents of Cu and Fe using a flame atomic absorption spectrophotometer, and the results are shown in table 1:
TABLE 1 Cu, Fe element contents of catalysts prepared in examples 1-8 and comparative example 1
Figure BDA0002871300870000071
Figure BDA0002871300870000081
The catalysts prepared in examples 1-8 and comparative example 1 all contained 100ppm SO2And 5% of H2Carrying out sulfiding poisoning for 24h at 300 ℃ in an air atmosphere of O, and then carrying out catalytic performance evaluation, wherein the catalyst evaluation atmosphere is as follows: 500ppm NH3，500ppm NO，5vol.％O2，N2The total gas flow is 400mL/min for balance gas, and GHSV is 400,000h-1The evaluation results are shown in Table 2:
table 2 results of catalytic performance of catalysts prepared in examples 1 to 8 and comparative example 1 after poisoning with water sulfur
Figure BDA0002871300870000082
As shown in Table 2, the results of the catalyst performance evaluation show that, in example 2, compared with comparative example 1, the core-shell structure Cu-SSZ-13@ Fe prepared in example 2 of the present inventionxOyThe catalyst has more excellent capability of resisting water-sulfur poisoning, and has the highest NO at 200-250 ℃ after the same-condition sulfidation poisoningx(NO、NO2、N2O) conversion, especially at 250 ℃, post-sulfided catalyst catalyzes NH3The conversion of SCR can reach 65.39%, which is 32.3% higher than that of the unmodified catalyst in comparative example 1, and 27.4% higher than that of the simple Fe-doped modified catalyst in comparative example 2.

Claims (10)

1. Preparation of Cu-SSZ-13@ Fe with core-shell structurexOyA method of catalyzing, comprising the steps of:
(1) dispersing a copper salt in water to prepare a copper salt aqueous solution, then adding an H-SSZ-13 molecular sieve to perform hydrothermal reaction, after the reaction is finished, performing solid-liquid separation, collecting solids, drying and roasting to obtain Cu-SSZ-13;
(2) dispersing the obtained Cu-SSZ-13 and CTAB in absolute ethyl alcohol, and uniformly mixing to obtain a mixed solution; dispersing iron salt and hexamethylenetetramine in water to prepare an iron salt aqueous solution;
(3) mixing the obtained mixed solution with an iron salt aqueous solution, then heating and refluxing for reaction, after the reaction is finished, carrying out solid-liquid separation, collecting solids, drying and roasting to obtain Cu-SSZ-13@ Fe with a core-shell structurexOyA catalyst.
2. The method of claim 1, wherein in step (1) the Cu is in an aqueous solution of a copper salt2+The concentration of (B) is 0.005-0.01 mol/L.
3. The method of claim 1, wherein the mass ratio of the copper salt to the H-SSZ-13 molecular sieve in step (1) is (0.1-0.2): 1.
4. the method according to claim 1, wherein the mass ratio of CTAB to Cu-SSZ-13 in step (2) is (2-0.1): 1.
5. the method according to claim 1, wherein the CTAB is added in step (2) in an amount of (0.05g-1g)/500mL of absolute ethanol.
6. The method of claim 1, wherein the mass ratio of the iron salt to the Cu-SSZ-13 in step (2) is (0.03-0.1): 1.
7. the method according to claim 1, wherein Fe is contained in the iron salt aqueous solution in the step (2)3+The concentration of (A) is 0.0002-0.0012 mol/L.
8. The method according to any one of claims 1 to 7, wherein the molar ratio of hexamethylenetetramine to the iron salt in step (2) is 5: 1.
9. Cu-SSZ-13@ Fe with a core-shell structure, obtainable by a process according to any one of claims 1 to 8xOyA catalyst.
10. The Cu-SSZ-13@ Fe with core-shell structure of claim 9xOyCatalyst in NH3SCR catalytic reaction, automobile exhaust treatment.
CN202011601816.1A 2020-12-30 2020-12-30 Cu-SSZ-13@ Fe with core-shell structurexOyCatalyst and preparation method thereof Pending CN112717990A (en)

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* Cited by examiner, † Cited by third party
Title
张冉冉: ""改性Cu-SSZ-13分子筛上NH3选择性催化还原NO的性能研究"", 《中国优秀硕士学位论文全文数据库（硕士）》 *
王俊强: ""Ce改性Cu-SSZ-13分子筛上NH3选择性催化还原NO的性能与机理研究"", 《中国优秀硕士学位论文全文数据库（硕士）》 *

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116603567A (en) * 2023-03-27 2023-08-18 湖北兴发化工集团股份有限公司 Catalyst for synthesizing 6-aminocapronitrile and preparation method and application thereof
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