CN110586145A - Cerium-zirconium-aluminum composite material with high thermal stability, preparation method and application thereof - Google Patents

Cerium-zirconium-aluminum composite material with high thermal stability, preparation method and application thereof Download PDF

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CN110586145A
CN110586145A CN201910831342.0A CN201910831342A CN110586145A CN 110586145 A CN110586145 A CN 110586145A CN 201910831342 A CN201910831342 A CN 201910831342A CN 110586145 A CN110586145 A CN 110586145A
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cerium
zirconium
salt
aluminum
composite material
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CN110586145B (en
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杜君臣
李红
张爱敏
冯丰
景小宇
郭淼鑫
唐振艳
赵云昆
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Kunming Institute of Precious Metals
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/92Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002Mixed oxides other than spinels, e.g. perovskite
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/14Phosphorus; Compounds thereof
    • B01J27/16Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr
    • B01J27/18Phosphorus; Compounds thereof containing oxygen, i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr with metals other than Al or Zr
    • B01J35/61
    • B01J35/615
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00Nanotechnology for materials or surface science, e.g. nanocomposites
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00Manufacture or treatment of nanostructures
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2523/00Constitutive chemical elements of heterogeneous catalysts

Abstract

The invention discloses a cerium-zirconium-aluminum composite material with high thermal stability, a preparation method and application thereof, relating to the technical field of catalytic materials, wherein the cerium-zirconium-aluminum composite material is expressed in an oxide form and comprises the following components: 40-90 wt% of alumina, 3-45 wt% of cerium oxide, 2-45 wt% of zirconium oxide and 1-10 wt% of phosphorus oxide. The material has large specific surface area and high temperature resistance, and can be used as an automobile exhaust catalyst carrier for application. The method for preparing a cerium-zirconium-aluminum composite material with high thermal stability comprises preparing a mixture A containing cerium salt, zirconium salt and aluminum salt in a liquid medium; adding a peptizing agent into the mixture A to obtain a sol B containing cerium salt, zirconium salt and aluminum salt; preparing a phosphate solution, adding the phosphate solution into the sol B, and stirring to obtain a sol C containing cerium salt, zirconium salt, aluminum salt and phosphorus salt; and standing the sol C at room temperature, and drying and roasting to obtain the cerium-zirconium-aluminum composite material with high thermal stability.

Description

Cerium-zirconium-aluminum composite material with high thermal stability, preparation method and application thereof
Technical Field
The invention relates to the technical field of catalytic materials, in particular to a cerium-zirconium-aluminum composite material with high thermal stability, a preparation method and application thereof.
Background
With the rapid development of the automobile industry in China, the environmental problems caused by the emission of automobile exhaust become increasingly prominent. In recent years, air pollution is serious in China, and pollution indexes of a plurality of central cities such as Beijing, Shenyang, Xian, Hangzhou and the like are frequently 'burst table'. The atmospheric pollution weather such as haze brings huge threats to human living environment, public health, urban landscape and the like.
The motor vehicle tail gas post-treatment catalyst is a key part for controlling the automobile tail gas emission and is also the most effective technical means for controlling the automobile emission in the world at present. In order to accelerate the treatment of atmospheric pollution in China, the Ministry of environmental protection in 12 months in 2016 issued by the State quality inspection Bureau of light automobile pollutant emission limits and measurement methods (six stages in China), the national VI standard changes the I-type experiment test cycle, the pollutant emission limits are tightened, the durable mileage of the post-treatment catalyst is increased, and the actual driving pollutant emission test is determined as a II-type experiment. The change of national VI working conditions and the tightening of regulations bring huge pressure to post-treatment catalyst manufacturers, and the high-performance motor vehicle exhaust purification catalyst meeting the national VI standards relates to three preparation technologies of preparation of carrier materials with high oxygen storage, high temperature resistance and high specific surface area, loading of noble metals and auxiliaries and coating of durable coatings, and needs the synergistic improvement of all the processes.
Because the cerium-zirconium composite oxide has the advantages of oxygen storage and release performance and high specific area of alumina, the cerium-zirconium-aluminum composite material with high thermal stability becomes a latest generation of vehicle exhaust aftertreatment carrier material. The research of the document appl.call.b78 (2008)210-220 shows that alumina in the cerium-zirconium-aluminum composite material with high thermal stability can form a diffusion barrier layer in the cerium-zirconium composite oxide, so that the aggregation and growth of the cerium-zirconium composite oxide particles at high temperature are inhibited, and simultaneously the transformation of gamma and delta phases to alpha phases is prevented by the cerium-zirconium composite oxide. However, the best specific surface area of the cerium-aluminum-based composite material prepared by impregnating cerium oxide and a stabilizer thereof on alumina by an impregnation method disclosed in patent CN1200954A and roasting at 900 ℃/10 hours is only 30m2And about/g. The cerium-zirconium-aluminum composite oxide consisting of 51 wt% of alumina, 14.2 wt% of cerium oxide and 34.8 wt% of zirconium oxide reported in patent WO2006/070201 has a specific surface area of only 43m after 1100 ℃/2 hours of heat aging2(ii) in terms of/g. The patent CN101745375B discloses a cerium-zirconium-aluminum-based composite oxide material, which is composed of 25-70 wt% of alumina, 20-60 wt% of ceria, 5-25 wt% of zirconia, 2-4.9 wt% of lanthanum oxide and 2-15 wt% of one or more stabilizing additives selected from rare earth oxides of Y, Eu, Gd, Tb and Sm. After the material is roasted at 1000 ℃/10 hours, the specific surface area is only maintained at 50-75 m2Between/g. It can be seen that although the existing cerium-zirconium-aluminum material shows good application prospects in the aspects of thermal stability, high oxygen storage, high specific surface area and the like, the specific surface area of the existing cerium-zirconium-aluminum material is seriously reduced after being calcined at 1000 ℃/10 hours, the performance of the existing cerium-zirconium-aluminum material for keeping the high specific surface area under the condition of long time and high temperature, namely the heat-resistant stability performance, still cannot meet the requirement of a catalyst carrier material, and the existing cerium-zirconium-aluminum material cannot be used as the carrier material in a motor vehicle exhaust aftertreatment catalyst facing to the national VI or higher standard.
Disclosure of Invention
The invention aims to provide a cerium-zirconium-aluminum composite material with high thermal stability, a preparation method and application thereof, so as to overcome the problem of insufficient thermal stability of the existing cerium-zirconium-aluminum material and meet the ultra-long durable requirement of the future motor vehicle exhaust aftertreatment catalyst.
One aspect of the present invention provides a cerium-zirconium-aluminum composite material with high thermal stability, which is expressed in the form of oxide and comprises the following components by weight: 40-90 wt% of alumina, 3-45 wt% of cerium oxide, 2-45 wt% of zirconium oxide and 1-10 wt% of phosphorus oxide. The phosphate is combined with cerium, zirconium, aluminum and other elements to form CePO4、AlPO4The equal diffusion barrier layer inhibits the condensation of Al-OH and the agglomeration and sintering of CeZrOx in the aging process, thereby increasing the specific surface area of the cerium-zirconium-aluminum material and enhancing the aging resistance. The cerium-zirconium-aluminum composite material with high thermal stability may contain, by weight, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90% of alumina, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45% of ceria, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45% of zirconia, and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10% of phosphorus oxide, wherein the cerium-zirconium-aluminum composite material with high thermal stability may have thermal stability in this range, and a high specific surface area may be maintained under high temperature conditions for a long time.
The further technical scheme is that the cerium-zirconium-aluminum composite material with high thermal stability is represented in an oxide form and comprises the following components: 40-60 wt% of alumina, 11-44 wt% of cerium oxide, 11-44 wt% of zirconium oxide and 5 wt% of phosphorus oxide. In a further technical scheme, the weight content of alumina in the high-thermal-stability cerium-zirconium-aluminum composite material calculated by oxide can be 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 and 60 percent; the cerium oxide may be present in an amount of 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45% by weight; the zirconia may be present in an amount of 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45% by weight; the content of the phosphorus oxide is preferably 5% by weight, including but not limited to the above range, in which the high thermal stability cerium-zirconium-aluminum composite material provided by the invention can not only maintain a large specific surface area under a high temperature condition for a long time, but also maintain a good oxygen storage capacity.
Another aspect of the present invention provides a method for preparing a cerium-zirconium-aluminum composite material with high thermal stability, comprising the following steps:
s1: preparing a mixture a comprising a cerium salt, a zirconium salt and an aluminium salt in a liquid medium;
s2: adding a peptizing agent into the mixture A to obtain a sol B containing a cerium salt, a zirconium salt and an aluminum salt;
s3: preparing a phosphate solution, adding the phosphate solution into the sol B, and stirring to obtain a sol C containing cerium salt, zirconium salt, aluminum salt and phosphorus salt;
s4: and standing the sol C at room temperature, and drying and roasting to obtain the cerium-zirconium-aluminum composite material with high thermal stability.
Further, the step S1 specifically includes: and adding the cerium salt, the zirconium salt and the aluminum salt into deionized water, and stirring to completely dissolve the cerium salt, the zirconium salt and the aluminum salt to obtain a mixture A.
In a further technical scheme, in the step S1, the cerium salt is one or more of cerium nitrate, ammonium cerium nitrate and cerium acetate; the zirconium salt is one or more of zirconium nitrate, zirconyl nitrate and zirconium acetate; the aluminum salt is one or more of aluminum nitrate and pseudo-boehmite.
The further technical scheme is that the peptizing agent in the step S2 is ammonia water. The peptizing agent is used for dispersing insoluble matters into a colloid system by a chemical method. This is generally accomplished by adding a small amount of a suitable electrolyte, known as a peptizing agent, to the washed precipitate. Different peptizing substances require different peptizing agents, which are closely related to ions capable of being adsorbed on the crystal surfaces of the peptizing substances. Peptizers are also stabilizers of the formed colloids. The dispersion is stabilized due to the formation of an electric double layer around the colloidal particles.
Further technical solution is that step S3 specifically includes: and adding one or more of diammonium hydrogen phosphate and ammonium dihydrogen phosphate into deionized water to form a phosphate solution, adding the phosphate solution into the sol B, and stirring for 8-12 hours to obtain a sol C containing cerium salt, zirconium salt, aluminum salt and phosphorus salt. Adding phosphate solution into the sol B and stirring to make the phosphate solution fully dissolved and react with cerium salt, zirconium salt and aluminum salt to generate Ce-O-P, Zr-O-P, Al-O-P and other structures, wherein the stirring time can be 8, 9, 10, 11 and 12 hours, including but not limited to the above examples. When the stirring time is too short, the reaction is insufficient, and a stable chemical bond cannot be generated, so that the prepared cerium-zirconium-aluminum composite material has poor thermal stability.
Further, the step S4 specifically includes: and standing the sol C at the temperature of 20-30 ℃ for 12-24 h, then drying the sol C in an oven at the temperature of 80-120 ℃, and finally roasting the sol C in a calcining furnace at the temperature of 500-800 ℃ for 2-10 h to obtain the cerium-zirconium-aluminum composite material with high thermal stability. And standing the sol C at the room temperature of 20-30 ℃, and standing at the temperature to obtain fine and stable crystal particles.
One aspect of the invention provides application of a cerium-zirconium-aluminum composite material with high thermal stability in the aftertreatment of automobile exhaust. For example, the cerium-zirconium-aluminum composite material with high thermal stability has large specific surface area and high temperature resistance, and can be used as a carrier material of a motor vehicle exhaust aftertreatment catalyst. When the cerium-zirconium-aluminum composite material is used as a carrier material of a motor vehicle exhaust aftertreatment catalyst, the cerium-zirconium-aluminum composite material with high thermal stability provided by the invention can be ground to obtain carrier material powder with a certain particle size, active metals Pt, Pd and Rh are loaded on the surface of the carrier material by a dipping method and a precipitation method independently or in combination with other cerium-zirconium materials, and then the carrier material is subjected to size mixing, coating and roasting to form the motor vehicle exhaust aftertreatment catalyst.
The invention takes phosphate solution as a thermal stability enhancing auxiliary agent to combine phosphorus with elements such as cerium, zirconium, aluminum and the like, thereby improving the aging resistance of the cerium-zirconium-aluminum material. The cerium-zirconium-aluminum material with enhanced thermal stability is prepared by adopting a sol-gel method. The sol-gel method is a method in which some salts are dissolved in water or other organic solvents to form a uniform salt solution, a sol is formed by hydrolysis, alcoholysis, or chelation, and the sol is dried to become a gel. The loading of the active component of the catalyst prepared by the sol-gel method is accompanied with the sol-gel forming process, so that the chemical components of the catalyst prepared by the method are uniformly distributed. The material prepared by the invention has the advantages of single phase structure, large specific surface area, high-temperature environment resistance, simple preparation method and easily obtained raw materials, can be used as a carrier material of a motor vehicle exhaust aftertreatment catalyst, and is suitable for industrial production.
Drawings
FIG. 1 is a sample XRD pattern for fresh state of comparative example 1 and examples 1-3;
FIG. 2 is an XRD pattern of samples of comparative example 1 and examples 1-3 in the aged state.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to specific embodiments. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
Comparative example 1
294.3g of aluminum nitrate, 15.1g of cerium nitrate and 14.0g of zirconium nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum sol in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 500 ℃ for 3h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 1
290.7g of aluminum nitrate, 15.1g of cerium nitrate and 14.0g of zirconium nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 0.9g of diammonium phosphate is weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum sol and stirred for 8 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 80 ℃ to constant weight, and then roasting in a muffle furnace at 500 ℃ for 3h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 2
275.9g of aluminum nitrate, 15.1g of cerium nitrate and 14.0g of zirconium nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. Weighing 4.7g of diammonium phosphate, adding the diammonium phosphate into deionized water to prepare 1mol/L phosphate solution, adding the phosphate solution into the cerium zirconium aluminum precipitated sol, and stirring for 10 hours. Standing at room temperature for 18h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 500 ℃ for 3h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 3
257.5g of aluminum nitrate, 15.1g of cerium nitrate and 14.0g of zirconium nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 9.3g of diammonium phosphate is weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum precipitated sol and stirred for 12 hours. Standing at room temperature for 24h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 120 ℃ to constant weight, and then roasting in a muffle furnace at 500 ℃ for 3h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
The crystal structure of the fresh samples of comparative example 1, example 2 and example 3 was characterized by X-ray diffraction technique. X-ray diffraction analysis (XRD) is mainly used for analyzing phase structure of catalyst, and prepared powdered sample is placed on X' pert Pro type X-ray diffractometer for analysis, its working voltage is 36 kilovolt (kV), working current is 30 milliampere (mA), and Cu target and Ka radiation source are adoptedThe graphite monochromator has a scanning range of 5-90 degrees for 2 theta, an experimental scanning range of 10-90 degrees for 0.02 degree for step length, and a scanning speed of 10 degrees/min. And, the obtained data can be used for phase analysis and grain size calculation by using MIDJade 6.5. X-ray diffraction analysis is a structural analysis method for analyzing the state of spatial distribution of internal atoms in a substance by X-ray diffraction caused by crystal formation. When X-rays having a certain wavelength are irradiated onto a crystalline substance, the X-rays are scattered by encountering regularly arranged atoms or ions within the crystal, and the phase of the scattered X-rays is enhanced in some directions, thereby exhibiting a characteristic diffraction phenomenon corresponding to the crystal structure. The diffracted X-rays satisfy the bragg (w.l.bragg) equation: 2dsin θ ═ n λ formula: λ is the wavelength of the X-rays; θ is the diffraction angle; d is the crystal plane spacing; n is an integer. The wavelength λ can be measured by a known X-ray diffraction angle, and the plane spacing, that is, the state of the regular arrangement of atoms or ions in the crystal, can be determined. The substance structure of the sample crystal can be determined by comparing the obtained diffraction X-ray intensity and surface spacing with a known table, that is, qualitative analysis.
The size of the grains can be calculated using the Scherrer formula as shown in formula (1):
in the formula: 1.θ is the half-peak width;
2.Dhklcrystal grain diameter in the normal direction of the crystal plane;
k is a Scherrer constant, and when the general requirement is not high, k is taken as l;
4.λ is X-ray wavelength, 0.154056 nm;
5. beta is the half-height width of the diffraction peak of the measured sample, and needs to be converted into radian (rad) in the calculation process.
The XRD pattern shown in fig. 1 was obtained by X-ray diffraction analysis, and as can be seen from fig. 1, the positions of diffraction peaks of examples 1 to 3 were consistent with those of comparative example 1, and characteristic peaks of cubic cerium-zirconium solid solution appeared at 28.6 °, 33.2 °, 47.7 ° and 56.7 ° for 2 θ, and γ -Al appeared at 65.6 ° for 2 θ2O3Characteristic peak of (2). Using Scherrer's formula, using midjade6.5 software to assist in grain size calculations, we found that the grain sizes of the cerium zirconium solid solutions of the fresh samples provided in comparative example 1, example 2, and example 3 were: the particle size was 7.6nm for comparative example 1, 6.7nm for example 1, 6.6nm for example 2 and 6.7nm for example 3. Thus, the grain size of the cerium-zirconium-aluminum composite material with high thermal stability prepared in examples 1 to 3 of the present invention was smaller.
Fig. 2 shows XRD spectra of the aged samples subjected to high temperature treatment provided in comparative example 1, example 2 and example 3. As can be seen from fig. 2, the cerium-zirconium-aluminum composite materials prepared by the invention in the aged state and with high thermal stability provided in examples 1-3 have the same characteristic peak as that of comparative example 1, and the main phase structure is a cubic cerium-zirconium solid solution structure. However, the phosphorus content is too high, so that the cerium-zirconium solid solution characteristic peak of tetragonal phase appears at 2 theta of 29.7 degrees. Using Scherrer formula, the grain size calculation was performed with the aid of the MIDJade6.5 software, and the grain sizes of the aged samples provided in comparative example 1, example 2, and example 3 were: the particle size was 9.2nm for comparative example 1, 8.1nm for example 1, 7.9nm for example 2 and 8.0nm for example 3. Therefore, the cerium-zirconium-aluminum composite material with high thermal stability prepared in the embodiments 1 to 3 of the invention can keep smaller grain size after long-time high-temperature aging treatment, so that the cerium-zirconium-aluminum composite material with high thermal stability provided in the embodiments 1 to 3 of the invention has better high temperature resistance.
Example 4
40g of pseudo-boehmite, 33.5g of ammonium ceric nitrate and 14.2g of zirconyl nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 4.1g of ammonium dihydrogen phosphate is weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum precipitated sol and stirred for 10 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 600 ℃ for 8h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 5
73.6g of aluminum nitrate, 20g of pseudo-boehmite, 24.9g of cerium acetate and 23.9g of zirconium acetate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 4.7g of diammonium phosphate is weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum gel and stirred for 10 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 800 ℃ for 10h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 6
147.2g of aluminum nitrate, 12g of cerium acetate, 25.2g of cerium nitrate and 29.3g of zirconium acetate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 4.7g of diammonium phosphate is weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum gel and stirred for 10 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 500 ℃ for 2h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 7
147.2g of aluminum nitrate, 55.5g of cerium nitrate, 10.5g of zirconium nitrate and 6.6g of zirconium nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 4.7g of diammonium phosphate is weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum gel and stirred for 10 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 700 ℃ for 5h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Example 8
147.2g of aluminum nitrate, 13.9g of cerium nitrate, 17.4g of zirconium nitrate, 20.24g of zirconyl nitrate and 18.6g of zirconium acetate are weighed and respectively added into deionized water to prepare a 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 1.9g of diammonium hydrogen phosphate and 2.4g of ammonium dihydrogen phosphate are weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum gel and stirred for 10 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 500 ℃ for 3h to obtain the fresh cerium-zirconium-aluminum composite material. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material.
Example 9
147.2g of aluminum nitrate, 33.3g of pseudo-boehmite, 1.3g of cerium nitrate, 1.6g of ammonium ceric nitrate, 0.9g of cerium acetate, 1.0g of zirconyl nitrate and 1.7g of zirconium nitrate are weighed and respectively added into deionized water to prepare 1mol/L solution. After the above solutions were mixed to prepare a cerium zirconium aluminum mixed solution, ammonia water having a concentration of 8 vol% was dropped at a flow rate of 10ml/min until the pH was 6.5. 1.9g of diammonium hydrogen phosphate and 2.4g of ammonium dihydrogen phosphate are weighed and added into deionized water to prepare 1mol/L phosphate solution, and the phosphate solution is added into the cerium zirconium aluminum gel and stirred for 10 hours. Standing at room temperature for 12h, drying the cerium-zirconium-aluminum gel in a constant-temperature drying oven at 100 ℃ to constant weight, and then roasting in a muffle furnace at 800 ℃ for 2h to obtain the fresh cerium-zirconium-aluminum composite material with high thermal stability. And roasting a part of fresh samples at 1000 ℃ for 10 hours to obtain the aged cerium-zirconium-aluminum composite material with high thermal stability.
Evaluation of specific surface area and oxygen storage Properties was carried out using fresh samples and aged samples subjected to high-temperature long-time treatment as provided in comparative example 1 and examples 1 to 9, wherein the specific surface area was determined by N2Adsorption-desorption experiments are commonly used to characterize the specific surface area and pore structure parameters of the catalyst. The experiment was carried out on a NOVA2000e model physical adsorption apparatus with high purity N2As adsorbate, ultrasonic cleaning calibrated empty tube, drying, weighing empty tube to obtain empty tube weight, loading 0.1g sample to be tested, degassing on an adsorption apparatus, heating to 150 deg.C at 30 deg.C/min, maintaining for 15min, and weighing total mass m of tube containing sampleGeneral assemblyThe mass m of the sample can be obtainedSample (A)=mGeneral assembly-mPipeAnd finally, selecting a proper program on the adsorption instrument to acquire adsorption and desorption data. The specific surface area (surface area per unit mass of the sample, in general m) was calculated from the collected data by the multipoint BET method2In terms of/g). Wherein the enrichment of molecules, atoms or ions etc. in the vicinity of the material interface can be called adsorption, wherein physical adsorption provides a method for determining the surface area, the average pore size and the pore size distribution of the catalyst support material, the BET adsorption theory is based on the Langmuir adsorption theory, and the basic assumption of the BET adsorption model is that:
(1) adsorption sites are homogeneous in the thermodynamic and kinetic sense (uniform surface properties of the adsorbent), the heat of adsorption being independent of surface coverage;
(2) the adsorption molecules have no interaction and no transverse interaction;
(3) adsorption may be multi-molecular and not necessarily complete with a monolayer followed by another;
(4) the first layer of adsorption is that gas molecules directly act on the surface of the solid, and the adsorption heat (E1) of the first layer of adsorption is different from that of the later layers of adsorption; the second and subsequent layers are the same gas molecules and the heat of adsorption is the same for each layer, which is the heat of liquefaction (EL) of the adsorbate.
And the evaluation of oxygen storage performance is to adopt a thermogravimetric analyzer to collect H at 550 DEG C2The weight loss of the constant temperature reduction was calculated. Wherein, the thermogravimetric Analyzer (TGA) is an instrument for detecting the temperature-mass change relationship of a substance by using a thermogravimetric method. Thermogravimetry is the measurement of the mass of a substance as a function of temperature (or time) at a programmed temperature. When the measured substance is sublimated, vaporized, decomposed into gas or loses crystal water in the heating process, the quality of the measured substance changes. The thermogravimetric curve is not a straight line but decreases. By analyzing the thermogravimetric curve, the change of the measured substance in degree can be known, and the lost substance can be calculated according to the weight loss.
The samples of comparative example 1 and examples 1-9 were measured as oxides with the weight percentages of alumina, ceria, zirconia, and phosphorous oxide in the samples as shown in table 1. The cerium-zirconium-aluminum composite material with high thermal stability provided by the invention does not exist in the form of simple oxides, but exists in the form of salts with various complex structures, and the measurement by an oxide method is used for simplifying the expression method of the composition of the cerium-zirconium-aluminum composite material with high thermal stability. The fresh state samples and the aged state samples of comparative example 1 and examples 1 to 9 were subjected to the above-described test methods, and the BET (specific surface area) and Oxygen Storage Capacity (OSC) of each sample were obtained, and the results are shown in table 1.
TABLE 1 evaluation of specific surface area and oxygen storage Properties in comparative example 1 and examples 1 to 9
As shown in Table 1, it can be seen that the cerium-zirconium-aluminum material sample provided in comparative example 1 is more specific in the fresh stateArea of 210m2(g), the specific surface area of the aged cerium-zirconium-aluminum material sample after being calcined at 1000 ℃ for 10 hours is drastically reduced to 67m2(ii) in terms of/g. It is thus seen that the high temperature condition for a long time has a bad influence on the specific surface area of the conventional cerium-zirconium-aluminum material, which is an important index for evaluating the catalyst support material. In contrast, the specific surface area of the cerium-zirconium-aluminum composite material with high thermal stability provided by the embodiment of the invention can be kept in a better range after being roasted at 1000 ℃ for 10 hours, and the specific surface area is 230-341 m in a fresh state2The specific surface area of the sample roasted at 1000 ℃ for 10 hours can be maintained at 70-90 m2(ii) in terms of/g. Compared with the cerium zirconium aluminum material provided by the comparative example 1, the specific surface area and the oxygen storage capacity of the cerium zirconium aluminum material are obviously improved. Compared with the existing cerium-zirconium-aluminum material, the cerium-zirconium-aluminum composite material with high thermal stability provided by the invention can still keep a better specific surface area after long-time high-temperature treatment, and has more excellent performance. The cerium-zirconium-aluminum composite materials with high thermal stability provided in examples 4 to 8 can maintain good oxygen storage capacity under long-term high-temperature treatment, and the oxygen storage capacity is reduced to 128 to 302 μmol/g less after being baked at 1000 ℃ for 10 hours.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims (9)

1. A cerium zirconium aluminium composite material with high thermal stability is characterized in that the composite material is expressed in the form of oxides and comprises the following components: 40-90 wt% of alumina, 3-45 wt% of cerium oxide, 2-45 wt% of zirconium oxide and 1-10 wt% of phosphorus oxide.
2. A highly thermally stable cerium zirconium aluminium composite material according to claim 1, characterized by the composition, expressed in oxide form, of: 40-60 wt% of alumina, 11-44 wt% of cerium oxide, 11-44 wt% of zirconium oxide and 5 wt% of phosphorus oxide.
3. The method for preparing the cerium-zirconium-aluminum composite material with high thermal stability in the claim 1 is characterized by comprising the following steps:
s1: preparing a mixture a comprising a cerium salt, a zirconium salt and an aluminium salt in a liquid medium;
s2: adding a peptizing agent into the mixture A to obtain a sol B containing a cerium salt, a zirconium salt and an aluminum salt;
s3: preparing a phosphate solution, adding the phosphate solution into the sol B, and stirring to obtain a sol C containing cerium salt, zirconium salt, aluminum salt and phosphorus salt;
s4: and standing the sol C at room temperature, and drying and roasting to obtain the cerium-zirconium-aluminum composite material with high thermal stability.
4. The method of claim 3, wherein the step S1 specifically comprises: and adding the cerium salt, the zirconium salt and the aluminum salt into deionized water, and stirring to completely dissolve the cerium salt, the zirconium salt and the aluminum salt to obtain a mixture A.
5. The method of claim 4, wherein in step S1, the cerium salt is one or more of cerium nitrate, ammonium cerium nitrate and cerium acetate; the zirconium salt is one or more of zirconium nitrate, zirconyl nitrate and zirconium acetate; the aluminum salt is one or more of aluminum nitrate and pseudo-boehmite.
6. The method of claim 3, wherein the peptizing agent is ammonia water in step S2.
7. The method of claim 3, wherein the step S3 specifically comprises: and adding one or more of diammonium hydrogen phosphate and ammonium dihydrogen phosphate into deionized water to form a phosphate solution, adding the phosphate solution into the sol B, and stirring for 8-12 hours to obtain a sol C containing cerium salt, zirconium salt, aluminum salt and phosphorus salt.
8. The method of claim 3, wherein the step S4 specifically comprises: and standing the sol C at the temperature of 20-30 ℃ for 12-24 h, then drying the sol C in an oven at the temperature of 80-120 ℃, and finally roasting the sol C in a calcining furnace at the temperature of 500-800 ℃ for 2-10 h to obtain the cerium-zirconium-aluminum composite material with high thermal stability.
9. Use of a highly thermally stable cerium zirconium aluminium composite material as claimed in claim 1 or 2 in a support for a catalyst for the aftertreatment of motor vehicle exhaust gases.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115636438A (en) * 2022-11-07 2023-01-24 润和科华催化剂(上海)有限公司 Preparation method of cerium-zirconium mixed oxide with high thermal stability

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1600418A (en) * 2003-09-25 2005-03-30 昆明贵研催化剂有限责任公司 Catalyst for decontaminating tail gas of motorcar and preparation method
CN1749165A (en) * 2005-08-26 2006-03-22 吉林大学 High heat stability ordered mesoporous aluminum phosphate material and its preparing method
CN101066530A (en) * 2006-05-22 2007-11-07 林方 Hydrodemetalizing catalyst and its prepn
KR100885311B1 (en) * 2007-09-04 2009-02-24 한국화학연구원 A co/phosphorus-alumina catalyst for fischer-tropsch synthesis and preparing method thereof
CN101433831A (en) * 2008-12-17 2009-05-20 天津大学 Preparation of homogeneous mischcrystal cerium-zirconium-aluminum coating material by coprecipitation method and technique thereof
JP2010095418A (en) * 2008-10-17 2010-04-30 Mazda Motor Corp Composite oxide for purifying exhaust gas and method for producing the same
CN101745375A (en) * 2008-12-15 2010-06-23 比亚迪股份有限公司 Cerium zirconium aluminum based multiple oxide material and preparing method thereof
CN102962047A (en) * 2012-11-12 2013-03-13 上海华明高纳稀土新材料有限公司 Aluminum-cerium-zirconium based composite oxide catalytic material and preparation method thereof
CN103464128A (en) * 2013-08-23 2013-12-25 上海华明高纳稀土新材料有限公司 Modified aluminum oxide with high heat stability and preparation method of modified aluminum oxide
CN109569566A (en) * 2018-12-04 2019-04-05 华微科技(苏州)有限公司 Compound hydrogen-storing material of cerium zirconium aluminium and preparation method thereof
CN109876793A (en) * 2019-03-17 2019-06-14 中自环保科技股份有限公司 A kind of three-way catalyst preparation method and its catalyst with high CO detergent power

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1600418A (en) * 2003-09-25 2005-03-30 昆明贵研催化剂有限责任公司 Catalyst for decontaminating tail gas of motorcar and preparation method
CN1749165A (en) * 2005-08-26 2006-03-22 吉林大学 High heat stability ordered mesoporous aluminum phosphate material and its preparing method
CN101066530A (en) * 2006-05-22 2007-11-07 林方 Hydrodemetalizing catalyst and its prepn
KR100885311B1 (en) * 2007-09-04 2009-02-24 한국화학연구원 A co/phosphorus-alumina catalyst for fischer-tropsch synthesis and preparing method thereof
JP2010095418A (en) * 2008-10-17 2010-04-30 Mazda Motor Corp Composite oxide for purifying exhaust gas and method for producing the same
CN101745375A (en) * 2008-12-15 2010-06-23 比亚迪股份有限公司 Cerium zirconium aluminum based multiple oxide material and preparing method thereof
CN101433831A (en) * 2008-12-17 2009-05-20 天津大学 Preparation of homogeneous mischcrystal cerium-zirconium-aluminum coating material by coprecipitation method and technique thereof
CN102962047A (en) * 2012-11-12 2013-03-13 上海华明高纳稀土新材料有限公司 Aluminum-cerium-zirconium based composite oxide catalytic material and preparation method thereof
CN103464128A (en) * 2013-08-23 2013-12-25 上海华明高纳稀土新材料有限公司 Modified aluminum oxide with high heat stability and preparation method of modified aluminum oxide
CN109569566A (en) * 2018-12-04 2019-04-05 华微科技(苏州)有限公司 Compound hydrogen-storing material of cerium zirconium aluminium and preparation method thereof
CN109876793A (en) * 2019-03-17 2019-06-14 中自环保科技股份有限公司 A kind of three-way catalyst preparation method and its catalyst with high CO detergent power

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
SILVA, FABIANO DE A. ET.AL: "Partial oxidation of methane on Pt catalysts: Effect of the presence of ceria-zirconia mixed oxide and of metal content", 《APPLIED CATALYSIS A-GENERAL》 *
吴群英等: "新型铈锆铝稀土储氧材料的研究进展", 《现代化工》 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115636438A (en) * 2022-11-07 2023-01-24 润和科华催化剂(上海)有限公司 Preparation method of cerium-zirconium mixed oxide with high thermal stability

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