CN111085214A - Cu-Co-Ce ternary metal oxide catalyst and preparation method and application thereof - Google Patents
Cu-Co-Ce ternary metal oxide catalyst and preparation method and application thereof Download PDFInfo
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- 229910044991 metal oxide Inorganic materials 0.000 title claims abstract description 35
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- 238000002360 preparation method Methods 0.000 title claims abstract description 10
- 229910052802 copper Inorganic materials 0.000 claims abstract description 21
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- 239000000126 substance Substances 0.000 claims abstract description 7
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims abstract description 3
- UBEWDCMIDFGDOO-UHFFFAOYSA-N cobalt(II,III) oxide Inorganic materials [O-2].[O-2].[O-2].[O-2].[Co+2].[Co+3].[Co+3] UBEWDCMIDFGDOO-UHFFFAOYSA-N 0.000 claims abstract description 3
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- 229910002651 NO3 Inorganic materials 0.000 claims description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 2
- 229930006000 Sucrose Natural products 0.000 claims description 2
- CZMRCDWAGMRECN-UGDNZRGBSA-N Sucrose Chemical compound O[C@H]1[C@H](O)[C@@H](CO)O[C@@]1(CO)O[C@@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 CZMRCDWAGMRECN-UGDNZRGBSA-N 0.000 claims description 2
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- GUBGYTABKSRVRQ-QUYVBRFLSA-N beta-maltose Chemical compound OC[C@H]1O[C@H](O[C@H]2[C@H](O)[C@@H](O)[C@H](O)O[C@@H]2CO)[C@H](O)[C@@H](O)[C@@H]1O GUBGYTABKSRVRQ-QUYVBRFLSA-N 0.000 claims description 2
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- 150000003839 salts Chemical class 0.000 claims description 2
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- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 abstract description 17
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 abstract description 17
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
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- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
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- 229910000510 noble metal Inorganic materials 0.000 description 3
- 238000003917 TEM image Methods 0.000 description 2
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- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
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- 238000007254 oxidation reaction Methods 0.000 description 2
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- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 229910000366 copper(II) sulfate Inorganic materials 0.000 description 1
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- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 1
- -1 platinum group metals Chemical class 0.000 description 1
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/83—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with rare earths or actinides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation 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
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/002—Mixed oxides other than spinels, e.g. perovskite
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
- B01J35/51—Spheres
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
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- Combustion & Propulsion (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
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- General Chemical & Material Sciences (AREA)
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Abstract
The invention discloses a Cu-Co-Ce ternary metal oxide catalyst and a preparation method and application thereof. The Cu-Co-Ce ternary metal oxide catalyst comprises hollow microspheres, wherein the hollow microspheres comprise a hollow cavity and a shell from inside to outside, and the shell comprises foam pores; the components of the shell comprise CuO and Co3O4And CeO2Wherein the molar ratio of the sum of the molar numbers of Cu and Co to Ce is 1: (0.25-4), and the molar ratio of Cu to Co is 1: (0.25 to 4); the average pore diameter of the pores is 5-20 nm, and the specific surface area is 20-100 m2g‑1. The Cu-Co-Ce ternary metal oxide catalyst has high CO catalytic activity, high resistance to hydrocarbon substances such as propylene and the like and good stability; it has low cost and can be continuously generated.
Description
Technical Field
The invention relates to a Cu-Co-Ce ternary metal oxide catalyst and a preparation method and application thereof.
Background
Environmental pollution and energy consumption are always two major problems which are closely concerned by people, and the emission of greenhouse gases is closely related to the two problems. One of the main sources of greenhouse gases is the exhaust gases emitted by automobiles. In the current automotive market, the vast majority of automobiles are still driven by internal combustion engines. Although the new combustion technology further improves the fuel efficiency, the temperature of the exhaust gas is reduced, and CO and hydrocarbon with higher concentration are generated, which is not beneficial to the catalytic conversion of the automobile exhaust. Lower exhaust gas temperatures and higher CO and hydrocarbon concentrations challenge existing catalyst technologies. Thus, reducing emissions of exhaust pollutants while improving fuel economy presents a significant challenge to the automotive industry.
Most commercial catalysts currently used in automobile exhaust gas use supported Platinum Group Metal (PGM) nanoparticles. However, there are some disadvantages to using platinum group metals as active materials: the abundance of the noble metal in the earth crust is very low, the reserves are extremely limited, and the use economic cost is high, which seriously restricts the sustainable development and the wide application of the noble metal catalyst in the industry. Moreover, in general, noble metal particles are easily sintered and agglomerated at high temperature, resulting in a decrease in the activity of the catalyst, thereby affecting the catalytic stability thereof. Meanwhile, when the catalyst is used for treating automobile exhaust, the activity of the catalyst is inhibited due to the competitive action of the interference of various hydrocarbon substances such as propylene and the like on the active sites of the catalyst, so that the practical application of PGM is limited. Therefore, a new method is developed, and a more economical and efficient catalyst is designed and prepared, so that the method has extremely important application value in treating CO in the actual automobile exhaust.
Disclosure of Invention
The invention provides a Cu-Co-Ce ternary metal oxide catalyst and a preparation method and application thereof, aiming at solving the defects of high cost and poor stability of an oxidation catalyst of automobile exhaust and the defects of catalytic activity inhibition of hydrocarbon substances such as propylene and the like in the prior art. The Cu-Co-Ce ternary metal oxide catalyst has high CO catalytic activity, high resistance to hydrocarbon substances such as propylene and the like and good stability; it has low cost and can be continuously generated.
In order to achieve the purpose, the invention adopts the following technical scheme:
a Cu-Co-Ce ternary metal oxide catalyst comprises hollow microspheres, wherein the hollow microspheres comprise hollow cavities and shells from inside to outside, and the shells comprise foam holes; the components of the shell comprise CuO and Co3O4And CeO2Wherein the molar ratio of the sum of the molar numbers of Cu and Co to Ce is 1: (0.25-4), and the molar ratio of Cu to Co is 1: (0.25 to 4); the average pore diameter of the pores is 5-20 nm, and the specific surface area of the hollow microspheres is 20-100 m2g-1。
In the present invention, the molar ratio of the sum of the Cu and Co to the Ce is preferably 1: (0.5 to 4), or (1:4) to (3:2), or 1: (1 to 4), or 1: (1.5 to 4), or 1: (0.25 to 1.5), or 1: (0.5 to 1.5), or (2:3) to (3:2), or 1: (1 to 1.5), or 1: (0.25 to 1), or 1: (0.5:1), or (1:1) to (3:2), or (3:2) to (4:1), or (3:2) to (2:1), or 1: (0.25-0.5).
In the present invention, the molar ratio of Cu to Co is preferably 1 (1 to 4), more preferably 1: 1.
In the present invention, the molar ratio of Cu, Co and Ce is preferably 2:2:1, or 3:3:4, or 1:1:3, or 1:1: 8; more preferably 1:1: 3.
In the present invention, the average pore diameter of the cells is preferably 10 to 15nm, such as 10.2nm, 11.2nm, 12.2nm or 12.9 nm. The average pore size of the invention is determined by methods conventional in the art, i.e., the nitrogen adsorption isotherm of the sample is taken at a working temperature of-196 ℃ and then calculated according to the Barrett-Joyner-halenda (bjh) model.
In the invention, the specific surface area of the hollow microspheres is preferably 30-60 m2g-1Preferably 40 ℃50m2g-1E.g. 30.7m2g-1、39.6m2g-1、42.2m2g-1Or 52.7m2g-1. The specific surface area of the invention is calculated according to the Brunauer-Emmett-teller (bet) model using methods conventional in the art and taking nitrogen adsorption isotherms of samples at a working temperature of-196 ℃.
In the present invention, the particle size of the hollow microsphere may be 400nm to 3 μm, preferably 600nm to 2 μm, and more preferably 1 μm.
In the present invention, the thickness of the outer case may be 40nm to 300 nm.
The invention also provides a preparation method of the Cu-Co-Ce ternary metal oxide catalyst, which comprises the following steps:
s1, preparing a precursor solution, wherein the precursor solution is an aqueous solution of the raw material; wherein the raw materials comprise a Cu source, a Co source, a Ce source and a saccharide substance;
the molar ratio of the sum of the molar numbers of Cu and Co in the precursor solution to Ce is 1: (0.25-4), and the molar ratio of Cu to Co is 1: (0.25 to 4);
the molar concentration of total metal ions in the precursor solution is 0.2-0.5 mol/L;
the mass concentration of the saccharide in the precursor solution is 2-30 g/L;
s2, atomizing the precursor solution to obtain aerosol;
s3, carrying out heat treatment on the aerosol to obtain the aerosol; the temperature of the heat treatment is 600-1000 ℃.
In the present invention, in step S1, the Cu source, the Co source, and the Ce source may be soluble salts of Cu, Co, and Ce, respectively, and preferably one or more of nitrate, sulfate, and hydrochloride.
In the present invention, in step S1, the total metal ion molar concentration in the precursor solution is preferably 0.3 mol/L. The total metal ion molar concentration in the precursor solution refers to the total molar concentration of Cu ions, Co ions and Ce ions in the precursor solution.
In the present invention, in step S1, the molar ratio of the sum of the molar numbers of Cu and Co to the molar number of Ce is preferably 1: (0.5 to 4), or (1:4) to (3:2), or 1: (1 to 4), or 1: (1.5 to 4), or 1: (0.25 to 1.5), or 1: (0.5 to 1.5), or (2:3) to (3:2), or 1: (1 to 1.5), or 1: (0.25 to 1), or 1: (0.5:1), or (1:1) to (3:2), or (3:2) to (4:1), or (3:2) to (2:1), or 1: (0.25-0.5).
In the present invention, in step S1, the molar ratio of Cu to Co is preferably 1 (1-4), more preferably 1: 1.
In the present invention, in step S1, the molar ratio of Cu, Co and Ce is preferably 2:2:1, or 3:3:4, or 1:1:3, or 1:1: 8; more preferably 1:1: 3.
In the present invention, in step S1, the saccharide may be a saccharide conventional in the art, and preferably includes one or more of dextrin, sucrose and maltose, and more preferably dextrin.
In the present invention, in step S1, the mass concentration of the saccharide in the precursor solution is preferably 10 to 20 g/L.
In the present invention, in step S2, the atomization may be performed in an atomization apparatus conventional in the art. The atomizing means is preferably an ultrasonic nebulizer, more preferably an ultrasonic nebulizer with three vibrators. The frequency of the atomization means is preferably 1.7 MHz. The carrier gas of the atomization device can be air, and the flow rate of the carrier gas is preferably 10L/min. The working process of the atomization device is as follows: atomizing the precursor solution into a large number of small droplets to obtain uniform aerosol; and the aerosol is blown into the heat treatment apparatus in step S3 by the carrier gas.
In the present invention, in step S3, the temperature of the heat treatment is preferably 800 ℃.
In the present invention, in step S3, the heat treatment may be performed in a conventional heat treatment apparatus, such as a tube furnace. The tube furnace preferably comprises a quartz tube reactor having a diameter of 900mm, a length of 1400mm and a constant temperature zone having a diameter of 900 mm. And in the heat treatment process, the processes of drying and dehydration, thermal decomposition, solidification and sintering and the like of the aerosol are generated to obtain a powdery product.
In the present invention, step S3 preferably further includes a collecting operation. The collecting operation may specifically be: the powdery product was collected on the filter paper by being carried by the air flow under the action of the vacuum pump.
The invention also provides the Cu-Co-Ce ternary metal oxide catalyst prepared by the preparation method of the Cu-Co-Ce ternary metal oxide catalyst.
The invention also provides an application of the Cu-Co-Ce ternary metal oxide catalyst in treating automobile exhaust.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows:
(1) the Cu-Co-Ce ternary metal oxide catalyst has a hollow microsphere structure, is large in specific surface area, has high CO catalytic activity, can realize complete conversion of CO at a lower temperature, shows higher resistance to hydrocarbons such as propylene and the like, and has long-term stability.
(2) The invention adopts the spray pyrolysis technology to prepare the Cu-Co-Ce ternary metal oxide catalyst, improves the dispersibility and uniformity of Cu, Co and Ce in the product, and can realize rapid and continuous generation.
(3) The Cu-Co-Ce ternary metal oxide catalyst provided by the invention has the advantages of abundant reserves of transition metals Cu, Co and Ce, wide raw material source and low price, and can greatly reduce the cost of an automobile exhaust emission control system.
Drawings
FIG. 1 is SEM images of Cu-Co-Ce ternary metal oxide catalysts prepared in examples 1-4 and comparative example 1, wherein (a) and (b) are example 1, (c) and (d) are example 2, (e) and (f) are example 3, (g) and (i) are example 4, and (j) and (k) are comparative example 1.
FIG. 2 is a TEM image of Cu-Co-Ce ternary metal oxide catalysts obtained in examples 1-4 and comparative example 1, wherein (a), (b) are example 1, (c), (d) are example 2, (e), (f) are example 3, (g), (h) are example 4, and (i), (j) are comparative example 1.
FIG. 3 is a nitrogen adsorption isotherm (a) and a pore diameter distribution diagram (b) of the Cu-Co-Ce ternary metal oxide catalysts prepared in examples 1-4 and comparative example 1.
FIG. 4 is a graph showing the relationship between the CO conversion efficiency and the temperature of the Cu-Co-Ce ternary metal oxide catalysts prepared in examples 1-4 and comparative example 1 under the conditions that (a) no propylene is contained and (b) propylene is contained.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
Example 1
A preparation method of a Cu-Co-Ce ternary metal oxide catalyst comprises the following steps:
s1, weighing CuSO4、CoSO4And CeSO4Dissolving the precursor solution in 100mL of deionized water, and dissolving the precursor solution in an ultrasonic water bath to form 0.2mol/L of precursor solution, wherein the molar ratio of Cu to Co to Ce is 1:1: 8; 2g of additive dextrin is weighed and added into the precursor solution, and the solution is continuously dissolved in an ultrasonic water bath.
S2, atomizing the liquid surface of the spraying solution into a large number of small droplets with the help of an ultrasonic atomizer with three vibrators (the frequency is 1.7MHz) to obtain uniform aerosol; and air with a flow rate of 10L/min was introduced as a carrier gas, and the aerosol was blown into a quartz tube reactor (diameter 900mm, length 1400mm, diameter of constant temperature zone 900mm) of the tube furnace.
S3, raising the temperature in a quartz tube reactor of the tube furnace to 800 ℃ to obtain a powdery product; the powdery product is carried by airflow under the action of a vacuum pump and collected on filter paper to obtain the Cu-Co-Ce ternary metal oxide catalyst.
Example 2
The molar ratio of Cu, Co and Ce is 1:1:3, other steps and conditions were the same as in example 1.
Example 3
The molar ratio of Cu, Co and Ce is 3:3:4, other steps and conditions were the same as in example 1.
Example 4
The molar ratio of Cu, Co and Ce is 2:2:1, other steps and conditions were the same as in example 1.
Comparative example 1
The molar ratio of Cu, Co and Ce is 5: 5: 0, other steps and conditions were the same as in example 1.
Effect example 1
The structures of the Cu-Co-Ce ternary metal oxide catalysts prepared in examples 1 to 4 and comparative example 1 were characterized, and the results are shown in fig. 1(SEM image) and fig. 2(TEM image). It can be seen that the five samples are all hollow microsphere structures, but raised cells (secondary cavities) were found on the shells of the microspheres in examples 1-4, whereas the microspheres of comparative example 1 have no distinct cells. The cells may be formed by the interaction of Ce with dextrin, and the formation of the cells greatly increases the specific surface area of the material. In a certain range, the higher the Ce content, the more the cells, and when the Ce content is increased to a certain value, the cells do not increase any more, but begin to decrease instead.
Effect example 2
The specific surface area and pore size distribution of the sample were analyzed using an ASAP 2460 fully automated specific surface area and pore size analyzer manufactured by macruick, usa. Before analysis, the samples were dried at 150 ℃ for 6h under nitrogen atmosphere to ensure complete removal of water. The nitrogen adsorption isotherms of the samples were taken at a working temperature of-196 ℃ and the results are shown in fig. 3(a), with all 5 samples showing a typical isothermal process type IV, indicating their mesoporous structure.
The specific surface area of the sample was calculated according to the Brunauer-Emmett-Teller (BET) model, and the results are shown in Table 1. The higher surface area favors the adsorption of the gaseous reactants to the catalyst. The analysis results of the specific surface areas show the high catalytic performance of the samples of examples 1 to 4.
TABLE 1
Example 1 | Example 2 | Example 3 | Example 4 | Comparative example 1 | |
Specific surface area/m2g-1 | 42.2 | 52.7 | 39.6 | 30.7 | 8.5 |
The pore size distribution of the sample was obtained according to Barrett-Joyner-Halenda (BJH) model, and the results are shown in FIG. 3 (b). The average cell diameters of the cells in the above 5 samples were calculated to be 12.2nm, 12.9nm, 10.2nm, 11.2nm and 11.5nm, respectively.
Effect example 3
Catalytic activity tests were conducted from a continuous flow fixed bed reactor. 50mg of the catalyst was diluted with 200mg of quartz sand (60-100 mesh), and the diluted catalyst was placed in a quartz tube (inner diameter 6mm), and quartz wool plugs were attached to both ends. A type k thermocouple connected to a heating system was embedded in the reactor to control the reaction temperature.
Before the measurement, the catalyst was at a temperature of 300 ℃ at 20% O 280% high purity argonIs heated for 30min to remove any residual impurities adsorbed on the surface, and is cooled to room temperature.
Then introducing the mixed gas containing CO into the reactor at a flow rate of 50mL min-1Corresponding hourly space velocity of 60000mL h-1gcat-1。
The reaction temperature was raised from 50 ℃ to 250 ℃ at a ramp rate of 10 ℃/h, held on each platform for 30min to reach a steady state, and then subjected to gas sample analysis.
The analysis of the gas samples was carried out on an on-line gas chromatograph system (GC 2060, shanghai Ruimin) equipped with a FID detector connected to a methane furnace. The CO conversion efficiency is determined according to the following formula:
wherein, CinDenotes the concentration of CO in the mixed gas introduced into the reactor, CoutWhich represents the CO concentration in the mixed gas flowing out of the reactor.
According to the method, the Cu-Co-Ce ternary metal oxide catalysts prepared in the examples 1-4 and the comparative example 1 are tested under the conditions of propylene and no propylene, and specifically, the mixed gas in the presence of propylene is 0.2% C3H6、1%CO、10%O2And a balance of Ar, wherein the mixed gas in the absence of propylene is 1% CO and 10% O2And a mixed gas of equilibrium Ar.
The relationship between the CO conversion efficiency and the temperature is shown in FIG. 4, and it can be seen that the catalysts of examples 1 to 4 have catalytic activity for CO at the beginning of 60 to 80 ℃ in the presence or absence of propylene, and the catalytic activity rapidly increases with the increase of the temperature. The catalytic activity in the absence of propylene is slightly higher than that in the presence of propylene, but with a minor difference. Taking the example 2 as an example, the Cu-Co-Ce ternary metal oxide catalyst of the example 2 has the highest catalytic activity, realizes the complete conversion of Co at 130 ℃ in the absence of propylene, and realizes the complete conversion of Co at 150 ℃ in the presence of propylene, and simultaneously shows higher catalytic oxidation performance of Co and stronger propylene resistance. Whereas the catalyst of comparative example 1 started to be catalytically active towards CO at around 140 c and still did not achieve complete conversion of CO above 220 c.
In addition, the Cu-Co-Ce ternary metal oxide catalyst of example 2 was also tested for long-term stability. 1% CO, 10% O were treated at 150 ℃ with the catalyst of example 2 according to the above-mentioned method for measuring catalytic activity2And a mixed gas of equilibrium Ar. Initially, the CO conversion efficiency was 100%, 95.5% after 40h, and the catalytic activity was only reduced by 4.5%.
Claims (10)
1. A Cu-Co-Ce ternary metal oxide catalyst comprises hollow microspheres, wherein the hollow microspheres comprise hollow cavities and shells from inside to outside, and the shells comprise foam holes; the components of the shell comprise CuO and Co3O4And CeO2Wherein the molar ratio of the sum of the molar numbers of Cu and Co to Ce is 1: (0.25-4), and the molar ratio of Cu to Co is 1: (0.25 to 4); the average pore diameter of the pores is 5-20 nm, and the specific surface area of the hollow microspheres is 20-100 m2g-1。
2. The Cu-Co-Ce ternary metal oxide catalyst of claim 1, wherein the molar ratio of the sum of the Cu and Co moles to Ce is 1: (0.5 to 4), or (1:4) to (3:2), or 1: (1 to 4), or 1: (1.5 to 4), or 1: (0.25 to 1.5), or 1: (0.5 to 1.5), or (2:3) to (3:2), or 1: (1 to 1.5), or 1: (0.25 to 1), or 1: (0.5:1), or (1:1) to (3:2), or (3:2) to (4:1), or (3:2) to (2:1), or 1: (0.25 to 0.5);
and/or the molar ratio of the Cu to the Co is 1 (1-4), preferably 1: 1.
And/or the molar ratio of Cu, Co and Ce is 2:2:1, or 3:3:4, or 1:1:3, or 1:1: 8; preferably 1:1: 3.
3. The Cu-Co-Ce ternary metal oxide catalyst according to claim 1, wherein the average pore size of the pores is 10-15 nm;
and/or the specific surface area of the hollow microspheres is 30-60 m2g-1Preferably 40 to 50m2g-1;
And/or the particle size of the hollow microsphere is 400 nm-3 μm, preferably 600 nm-2 μm, and more preferably 1 μm;
and/or the thickness of the shell is 40 nm-300 nm.
4. A preparation method of a Cu-Co-Ce ternary metal oxide catalyst comprises the following steps:
s1, preparing a precursor solution, wherein the precursor solution is an aqueous solution of the raw material; wherein the raw materials comprise a Cu source, a Co source, a Ce source and a saccharide substance;
the molar ratio of the sum of the molar numbers of Cu and Co in the precursor solution to Ce is 1: (0.25-4), and the molar ratio of Cu to Co is 1: (0.25 to 4);
the molar concentration of total metal ions in the precursor solution is 0.2-0.5 mol/L;
the mass concentration of the saccharide in the precursor solution is 2-30 g/L;
s2, atomizing the precursor solution to obtain aerosol;
s3, carrying out heat treatment on the aerosol to obtain the aerosol; the temperature of the heat treatment is 600-1000 ℃.
5. The method of claim 4, wherein in step S1, the Cu source, the Co source and the Ce source are soluble salts of Cu, Co and Ce, preferably one or more of nitrate, sulfate and hydrochloride;
and/or in step S1, the molar ratio of the sum of the molar numbers of Cu and Co to Ce is 1: (0.5 to 4), or (1:4) to (3:2), or 1: (1 to 4), or 1: (1.5 to 4), or 1: (0.25 to 1.5), or 1: (0.5 to 1.5), or (2:3) to (3:2), or 1: (1 to 1.5), or 1: (0.25 to 1), or 1: (0.5:1), or (1:1) to (3:2), or (3:2) to (4:1), or (3:2) to (2:1), or 1: (0.25 to 0.5);
and/or in step S1, the molar ratio of Cu to Co is 1 (1-4), preferably 1: 1;
and/or in step S1, the molar ratio of Cu, Co and Ce is 2:2:1, or 3:3:4, or 1:1:3, or 1:1: 8; preferably 1:1: 3;
and/or in step S1, the molar concentration of the total metal ions in the precursor solution is 0.3 mol/L.
6. The method of claim 4, wherein in step S1, the saccharide includes one or more of dextrin, sucrose and maltose, preferably dextrin;
and/or in step S1, the mass concentration of the saccharide substance in the precursor solution is 10-20 g/L.
7. The method for preparing the Cu-Co-Ce ternary metal oxide catalyst according to claim 4, wherein in step S2, the atomizing device is an ultrasonic atomizer, preferably an ultrasonic atomizer with three vibrators;
and/or the frequency of the atomization device is 1.7 MHz;
and/or the carrier gas of the atomization device is air, and the flow rate of the carrier gas is preferably 10L/min.
8. The method for preparing the Cu-Co-Ce ternary metal oxide catalyst according to claim 4, wherein in step S3, the temperature of the heat treatment is 800 ℃;
and/or in step S3, the heat treatment equipment for heat treatment is a tube furnace; the tube furnace preferably comprises a quartz tube reactor with a diameter of 900mm, a length of 1400mm and a diameter of 900mm in a constant temperature region;
and/or, step S3 further includes a collecting operation; the collecting operation is preferably: the powdery product was collected on the filter paper by being carried by the air flow under the action of the vacuum pump.
9. A Cu-Co-Ce ternary metal oxide catalyst, which is prepared by the preparation method of the Cu-Co-Ce ternary metal oxide catalyst according to any one of claims 4-8.
10. Use of the Cu-Co-Ce ternary metal oxide catalyst according to any one of claims 1-3 or claim 9 for treating automobile exhaust.
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CN108607611A (en) * | 2018-04-19 | 2018-10-02 | 上海理工大学 | A kind of Cu-Ce-Zr mixed metal oxide catalysts |
CN108940302A (en) * | 2018-07-19 | 2018-12-07 | 南京工业大学 | Composite metal oxide catalyst and preparation method and application thereof |
CN110893343A (en) * | 2019-09-07 | 2020-03-20 | 苏州羿白环保科技有限公司 | Preparation method of ternary oxide non-noble metal catalyst |
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CN108607611A (en) * | 2018-04-19 | 2018-10-02 | 上海理工大学 | A kind of Cu-Ce-Zr mixed metal oxide catalysts |
CN108940302A (en) * | 2018-07-19 | 2018-12-07 | 南京工业大学 | Composite metal oxide catalyst and preparation method and application thereof |
CN110893343A (en) * | 2019-09-07 | 2020-03-20 | 苏州羿白环保科技有限公司 | Preparation method of ternary oxide non-noble metal catalyst |
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