CN111974410A - Preparation method and application of high-performance perovskite catalyst in-situ reduction Pt nanoparticles - Google Patents

Preparation method and application of high-performance perovskite catalyst in-situ reduction Pt nanoparticles Download PDF

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CN111974410A
CN111974410A CN201910444518.7A CN201910444518A CN111974410A CN 111974410 A CN111974410 A CN 111974410A CN 201910444518 A CN201910444518 A CN 201910444518A CN 111974410 A CN111974410 A CN 111974410A
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perovskite catalyst
perovskite
temperature
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catalyst
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曾丽蓉
龚彩荣
崔兰
王彩云
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Tianjin University
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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
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8933—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/894—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with rare earths or actinides
    • 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
    • B01J35/397—
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B01J37/036—Precipitation; Co-precipitation to form a gel or a cogel
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/16—Reducing
    • B01J37/18—Reducing with gases containing free hydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y02A50/2351—Atmospheric particulate matter [PM], e.g. carbon smoke microparticles, smog, aerosol particles, dust

Abstract

The invention discloses a preparation method and application of high-performance perovskite catalyst in-situ reduction Pt nanoparticles, wherein the Pt nanoparticles are uniformly grown on the surface of a perovskite catalyst by carrying out in-situ reduction treatment in a reducing atmosphere, wherein the initial perovskite catalyst is prepared by a sol-gel method. The catalyst is applied to the field of diesel engine tail gas purification treatment, and can effectively reduce the emission of carbon smoke particles, thereby achieving the purpose of reducing the air pollution degree.

Description

Preparation method and application of high-performance perovskite catalyst in-situ reduction Pt nanoparticles
Technical Field
The invention relates to a preparation method and application of a surface modified perovskite catalyst for diesel engine tail gas purification, which is applied to catalytic oxidation of soot particles in diesel engine tail gas and belongs to the technical field of diesel engine tail gas purification catalysts.
Background
At present, with the rising development of economy, automobiles become indispensable transportation means in the modern society, and among them, diesel engines are widely used due to their excellent performances such as high efficiency, stability, and air-fuel ratio. However, the harmful gases (such as particulate matter, carbon monoxide, hydrocarbons, nitrogen oxides) generated by the method are seriously threatened to the ecological environment and human health. Therefore, it is necessary to effectively reduce the exhaust emissions, whether environmental degradation or health threat, and the key to the diesel exhaust after-treatment technology is in the middle. Particulate Filters (DPF) are currently one of the most well recognized and most effective technologies for the aftertreatment of automobile exhaust. The filter with a special structure is made of high-temperature-resistant materials serving as a substrate, and can adsorb particulate matters in a filter body in an adsorption mode and recover the performance of the materials through a regeneration device, so that the particulate matter purification effect is achieved. However, the system operates above 600 ℃ in the absence of catalyst, which is higher than the normal operating temperature of a diesel engine (200 ℃ -500 ℃).
According to previous researches, perovskite catalysts are the most widely researched catalysts with the lowest cost and high thermal stability, and are widely applied to the field of diesel engine exhaust purification. The perovskite oxide is ideally a cubic crystal, with an alkaline earth metal at the A site coordinated to the neighboring atom 12 and an transition metal element at the B site coordinated to the oxygen element 6 to form a regular octahedral structure. Numerous studies have shown that the active center of the perovskite catalyst is at the B-site, determining the catalytic activity of the catalyst. B-substituted LaCo is prepared by Minicao and the like by adopting a sol-gel method 1-xRexO3-The (x ═ 0.04) type perovskite composite oxide catalyst Re (Pt, Pd, Rh, Au, Ag) was found to have a significantly improved catalytic activity. However, the perovskite oxide nanoparticles in the traditional sense have large sizes, most of the perovskite oxide nanoparticles are more than 100nm, so that the perovskite oxide nanoparticles have low surface areas and cannot be in good contact with soot particles, and the advantages of the perovskite oxide nanoparticles are prevented from being exerted.Meanwhile, researches also find that the supported perovskite catalyst can effectively increase the surface area of the catalyst, can ensure the dispersity of the active components and reduce the agglomeration of the active components. Therefore, the selection and development of a supported perovskite catalyst has great application prospect, and the in-situ reduction means is one of the most convenient means and the means capable of ensuring the dispersity.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a preparation method and application of high-performance perovskite catalyst in-situ reduction Pt nanoparticles, and aims to uniformly grow a layer of Pt nanoparticles on the surface of a catalyst to effectively remove pollutants in diesel engine tail gas.
The technical purpose of the invention is realized by the following technical scheme.
The preparation method of the high-performance perovskite catalyst in-situ reduction Pt nano-particles comprises the following steps:
step 1, lanthanum nitrate (La (NO)3)3·6H2O), cobalt nitrate (Co (NO)3)2·6H2O) and platinum nitrate (Pt (NO)3)2) Adding into deionized water to obtain solution, adding ethylenediamine tetraacetic acid and citric acid into the solution, wherein the metal ion (i.e. the sum of metal lanthanum, metal cobalt and metal platinum; the proportion of the three metal ions can be matched according to the requirement of a chemical expression), and the molar ratio of the ethylenediamine tetraacetic acid to the citric acid is (1-2): (1-2): (2-4), the concentration of the perovskite solution is 0.08-0.12 mol/L, and 20-30% ammonia water (NH) is dripped into the solution3·H2O, ammonia with the mass percentage of 20-30 percent), adjusting the pH value of the solution to 6-7, ultrasonically dispersing the solution, transferring the solution to a magnetic stirrer with a water bath, and uniformly stirring the solution to obtain wet gel;
in step 1, the molar ratio of metal ions (the sum of metal lanthanum, metal cobalt and metal platinum), ethylenediamine tetraacetic acid and citric acid is 1: 1: 2, the concentration of the perovskite solution is 0.10mol/L (namely the sum of the metal ion concentrations).
In step 1, after ultrasonic dispersion, the aqueous solution is placed in a water bath apparatus at a water bath temperature of 70 to 90 ℃, preferably 80 to 90 ℃, and magnetically stirred at a magnetic stirring speed of 300 to 500r/min, preferably 400 to 500r/min, to obtain a wet gel.
And 2, transferring the wet gel obtained in the step 1 into an oven, heating the wet gel from the room temperature of 20-25 ℃ to 100-120 ℃ at the heating rate of 1-5 ℃/min, preserving the temperature to form dry gel, then transferring the wet gel into a muffle furnace, heating the wet gel from the room temperature of 20-25 ℃ to 200-400 ℃ at the temperature of 5-10 ℃/min in the air atmosphere, preserving the temperature to completely decompose the citric acid, heating the wet gel to the temperature of 700-900 ℃ at the temperature of 5-10 ℃/min, preserving the temperature for 1-5 h, and cooling the wet gel to the room temperature of 20-25 ℃ along with the furnace to obtain the perovskite catalyst which is not subjected to surface modification.
In step 2, the wet gel is kept at 100-120 ℃ for 12-24 h to form xerogel.
In step 2, the temperature is raised to 200-400 ℃ in a muffle furnace and is kept for 1-5 h to completely decompose the citric acid, and the temperature is preferably kept for 2-4 h at 300-400 ℃.
In step 2, the temperature is preferably raised to 800-900 ℃ and kept for 3-5 h.
Step 3, placing the perovskite catalyst which is obtained in the step 2 and is not subjected to surface modification in a tubular furnace, and introducing mixed gas of hydrogen and inert protective gas at the room temperature of 20-25 ℃ to exhaust air; then in the mixed gas atmosphere of hydrogen and inert protective gas, heating from the room temperature of 20-25 ℃ to 350-500 ℃ at the heating rate of 1-5 ℃/min, carrying out heat preservation treatment, and cooling to the room temperature of 20-25 ℃ along with the furnace; the volume percentage of hydrogen in the mixed gas of hydrogen and inert protective gas is 3-5%.
In step 3, the inert shielding gas is argon, nitrogen or helium.
In step 3, the reduction temperature is preferably 350 to 400 ℃, and the heat preservation treatment time is 1 to 5 hours, preferably 2 to 4 hours.
In step 3, the flow rate of the mixed gas of hydrogen and inert protective gas is 15-30 mL/min.
The invention also discloses the perovskite prepared by the methodMineral catalyst (LaCo)1-xPtxO3X is greater than zero and less than or equal to 0.1), and the use of the above method in the purification of diesel engine exhaust, such as the catalytic oxidation of soot particles in diesel engine exhaust.
According to the perovskite catalyst prepared by the method, Pt is reduced from crystal lattices to the surface through reducing gas to form Pt nano particles, and oxygen vacancies in the perovskite crystal lattices are increased, so that the catalytic activity of the perovskite catalyst is improved.
The ideal perovskite molecular formula is ABO3The structure is that La is selected as an A-site element, Co is selected as a B-site element, the Co element at the B site is partially replaced by the Pt element, a nitrate raw material is selected to ensure the supply of oxygen atoms, and N atoms are removed by high-temperature roasting in the preparation process to finally form a target product LaCo1-xPtxO3A perovskite catalyst of a structure (x is greater than zero and 0.1 or less). According to the technical scheme, the Pt nano particles are uniformly grown on the surface of the perovskite catalyst by performing in-situ reduction treatment in a reducing atmosphere, wherein the initial perovskite catalyst is prepared by a sol-gel method, the preparation method has the advantages of being simple and convenient to operate and short in time consumption, and then B-site Pt ions in the structure of the perovskite catalyst are directly reduced in the reducing atmosphere, so that the surface of the perovskite catalyst is uniformly loaded with noble metal, and meanwhile, oxygen vacancies are enriched in perovskite crystal lattices (namely, Pt is reduced from the crystal lattices to the surface by reducing gas to form the Pt nano particles). The catalyst is applied to the field of diesel engine tail gas purification treatment, and can effectively reduce the emission of carbon smoke particles, thereby achieving the purpose of reducing the air pollution degree.
Compared with the prior art, the catalytic activity is obviously improved after the perovskite catalyst is subjected to in-situ reduction treatment. The perovskite catalyst which is low in price, efficient and stable and is subjected to in-situ reduction overcomes the defect of low specific surface area of the traditional perovskite catalyst, the catalyst is treated by using hydrogen atmosphere, the operation is simple and convenient, and the introduction of other chemical impurities is avoided. The method can not only ensure that the perovskite structure is not damaged, but also improve the surface area of the catalyst and the contact efficiency of the catalyst to soot by growing the Pt nanoparticles on the surface of the catalyst, thereby improving the catalytic oxidation efficiency of the soot of the catalyst and greatly improving the environmental damage caused by the pollution of the tail gas of the diesel engine and the threat to human health.
Drawings
FIG. 1 is H of example 1 of the present invention2-TPR diffraction pattern.
FIG. 2 is an XRD diffraction pattern of a sample of an embodiment of the present invention.
FIG. 3 is a SEM photograph and a schematic diagram of energy spectrum test results of example 1 of the present invention.
FIG. 4 is a SEM photograph and a schematic diagram of energy spectrum test results of example 2 of the present invention.
FIG. 5 is a SEM photograph and a schematic diagram of energy spectrum test results of example 3 of the present invention.
FIG. 6 is a TG curve of a sample of an example of the present invention.
Detailed Description
The technical solution of the present invention is further illustrated by the following specific examples.
Example 1
1. According to the formula LaCo of the perovskite catalyst0.94Pt0.06O3Proportioning, namely weighing 2.165g of lanthanum nitrate (La (NO)3)3·6H2O), 1.426g of cobalt nitrate (Co (NO)3)3·6H2O), 0.012g of platinum nitrate (Pt (NO)3)2Dissolved in 50mL of distilled water and magnetically stirred to form a 0.1M solution.
2. 2.9224g of ethylenediamine tetraacetic acid (EDTA) in an amount equivalent to the molar ratio of the total metal ions and 4.2028g of citric acid (citric acid) in a molar ratio of 1:2 to the total metal ions were added to the above solutions, and the above solutions were stirred until dissolved.
3. The pH of the solution was adjusted to 6 with ammonia.
4. The solution was kept in a water bath at 80 ℃ for 8h to form a wet gel.
5. And (3) putting the obtained wet gel into an oven, heating to 120 ℃ at the heating rate of 5 ℃/min, preserving heat for 24h to form dry gel, transferring to a muffle furnace, heating to 400 ℃ at the heating rate of 10 ℃/min, preserving heat for 3h to completely decompose citric acid, heating to 800 ℃, preserving heat for 5h, and cooling to room temperature of 20 ℃ along with the furnace to obtain the perovskite catalyst without surface modification.
Example 2
Placing the catalyst prepared in the example 1 in a tubular furnace, and introducing a mixed gas of hydrogen and inert protective gas at room temperature to exhaust air; then in the mixed gas atmosphere of hydrogen and inert protective gas, heating from the room temperature of 20-25 ℃ to 350 ℃ at the heating rate of 5 ℃/min, carrying out heat preservation treatment for 4h, and cooling to the room temperature along with the furnace; in the mixed gas of hydrogen and inert shielding gas, the volume percentage of hydrogen is 5%, and the flow rate of the mixed gas of hydrogen and inert shielding gas is controlled at 30 mL/min.
Example 3
Placing the catalyst prepared in the example 1 in a tubular furnace, and introducing a mixed gas of hydrogen and inert protective gas at room temperature to exhaust air; then in the mixed gas atmosphere of hydrogen and inert protective gas, heating from the room temperature of 20-25 ℃ to 500 ℃ at the heating rate of 5 ℃/min, carrying out heat preservation treatment for 4h, and cooling to the room temperature along with the furnace; in the mixed gas of hydrogen and inert shielding gas, the volume percentage of hydrogen is 5%, and the flow rate of the mixed gas of hydrogen and inert shielding gas is controlled at 30 mL/min.
The sample of example 1 was first analyzed for reducing performance (H)2TPR), the temperature value during the in situ reduction is determined. The equipment adopts a programmed temperature desorption instrument of Kangta company, firstly 50mg of sample is weighed and placed in a U-shaped quartz tube, and then N is added2The sample was pretreated at 400 ℃ under an atmosphere to remove impurities in the sample. When the temperature is reduced to room temperature, the temperature is switched to H2In the Ar atmosphere, the flow rate is controlled at 100mL/min, the temperature is increased to 900 ℃ at 10 ℃/min, and the temperature is kept for 15 min. In this process, the data is monitored by a thermal conductivity detector. The test results are shown in FIG. 1. Two reduction peaks are obviously seen from the figure, and the reduction peak at 350-450 ℃ is attributed to Co in the perovskite lattice 3+Conversion to Co2+The reduction peak at 450-500 ℃ belongs to Co in the perovskite lattice2+Conversion to elemental CoThe peak position. Therefore, in the present invention, 2 sets of characteristic temperatures are selected, one being 350 ℃ below the reduction temperature at which the perovskite lattice is destroyed, and the other being 500 ℃ below the temperature at which the perovskite lattice is completely destroyed.
The catalyst prepared by the invention is subjected to structural characterization (XRD), as shown in figure 2, PDF card comparison shows that the perovskite catalyst is successfully prepared in example 1, and the perovskite structure of the sample is still maintained after 350 ℃ in-situ reduction, and the perovskite crystal lattice is destroyed when the temperature is increased to 500 ℃. In addition, since the doped Pt in the examples is very trace and does not reach the measurement precision of XRD, the phase of Pt particles is not detected in an XRD spectrogram after in-situ reduction.
As can be seen from the SEM images of the examples, the surface of the perovskite was not found to have any particulate matter before the in-situ reduction treatment, and Pt nanoparticles were uniformly grown on the surface of the perovskite after the in-situ reduction at 350 ℃, while the surface of the perovskite became disordered after the in-situ reduction at 500 ℃. Elemental analysis of the examples revealed that the Pt content was close to the theoretical value, indicating that Pt (i.e., a large amount of Pt) was reduced from the crystal lattice to the surface by the reducing gas to form Pt nanoparticles.
The thermogravimetric analyzer device performed performance analysis on the sample. The thermogravimetric analyzer has a main body as furnace body, which is a heating body operating under a certain temperature program, and different dynamic atmospheres (such as N) can be introduced into the furnace2Ar, He, etc. protective atmosphere, O2An oxidizing atmosphere such as air, and other special atmospheres), or under vacuum or a static atmosphere. The current weight of the sample is sensed at any time by a high-precision balance connected to the lower part of the sample support in the test process, the data is transmitted to a computer, and a curve (TG curve) of the weight of the sample to the temperature/time is drawn by the computer. When the weight of the sample changes (the reasons include decomposition, oxidation, reduction, adsorption and desorption, etc.), the weight loss (or weight gain) step is represented on the TG curve, so that the temperature region of the weight loss/gain process can be known, and the weight loss/gain ratio can be quantitatively calculated. The invention selects air atmosphere to test in the testing process, 10mg of sample is weighed and is added in 1The test was carried out with a temperature rise rate of 10 ℃/min from 30 ℃ to 800 ℃ in a gas stream of 00 ml/min. And converting the tested data into conversion rate to obtain the result shown in the figure 6.
It can be seen from FIG. 6 that the in situ reduced catalyst started to convert at a lower temperature, while the sample of example 1 had a higher transition temperature. And the lowest soot conversion temperature of the catalyst without the perovskite lattice being destroyed, indicates that perovskite is still the main active component in the present invention.
The preparation of surface-modified perovskite catalysts can be achieved by adjusting the process parameters according to the content of the invention, and the performance of the perovskite catalysts is basically consistent with that of the invention. The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims (10)

1. The preparation method of the high-performance perovskite catalyst in-situ reduction Pt nano-particles is characterized by comprising the following steps:
step 1, lanthanum nitrate (La (NO)3)3·6H2O), cobalt nitrate (Co (NO)3)2·6H2O) and platinum nitrate (Pt (NO)3)2) Adding the solution into deionized water to prepare a solution, and adding ethylene diamine tetraacetic acid and citric acid into the solution, wherein the molar ratio of metal ions to the ethylene diamine tetraacetic acid to the citric acid is (1-2): (1-2): (2-4), the concentration of the perovskite solution is 0.08-0.12 mol/L, and 20-30% ammonia water (NH) is dripped into the solution3·H2O, ammonia with the mass percentage of 20-30 percent), adjusting the pH value of the solution to 6-7, ultrasonically dispersing the solution, transferring the solution to a magnetic stirrer with a water bath, and uniformly stirring the solution to obtain wet gel;
Step 2, transferring the wet gel obtained in the step 1 into an oven, heating the wet gel from room temperature 20-25 ℃ to 100-120 ℃ at a heating rate of 1-5 ℃/min, preserving heat to form dry gel, then transferring the wet gel into a muffle furnace, heating the wet gel from room temperature 20-25 ℃ to 200-400 ℃ at a temperature of 5-10 ℃/min in an air atmosphere, preserving heat to completely decompose citric acid, heating the wet gel to 700-900 ℃ at a temperature of 5-10 ℃/min, preserving heat for 1-5 h, and cooling the wet gel to room temperature 20-25 ℃ along with the furnace to obtain a perovskite catalyst which is not subjected to surface modification;
step 3, placing the perovskite catalyst which is obtained in the step 2 and is not subjected to surface modification in a tubular furnace, and introducing mixed gas of hydrogen and inert protective gas at the room temperature of 20-25 ℃ to exhaust air; then in the mixed gas atmosphere of hydrogen and inert protective gas, heating from the room temperature of 20-25 ℃ to 350-500 ℃ at the heating rate of 1-5 ℃/min, carrying out heat preservation treatment, and cooling to the room temperature of 20-25 ℃ along with the furnace; the volume percentage of hydrogen in the mixed gas of hydrogen and inert protective gas is 3-5%.
2. The method for preparing high-performance perovskite catalyst in-situ reduction Pt nanoparticles according to claim 1, wherein in step 1, the molar ratio of metal ions (metal lanthanum, metal cobalt and metal platinum) to ethylenediamine tetraacetic acid to citric acid is 1: 1: 2, the concentration of the perovskite solution is 0.10mol/L (namely the sum of the metal ion concentrations).
3. The preparation method of the high-performance perovskite catalyst in-situ reduction Pt nanoparticles as claimed in claim 1, wherein in step 1, after ultrasonic dispersion, the aqueous solution is placed in a water bath device with a water bath temperature of 70-90 ℃, preferably 80-90 ℃, and is stirred under magnetic force with a magnetic stirring speed of 300-500 r/min, preferably 400-500 r/min, so as to obtain wet gel.
4. The method for preparing Pt nanoparticles in situ reduced by high performance perovskite catalyst as claimed in claim 1, wherein in step 2, the wet gel is incubated at 100-120 ℃ for 12-24 h to form xerogel.
5. The preparation method of the high-performance perovskite catalyst in-situ reduction Pt nanoparticles as claimed in claim 1, wherein in the step 2, the temperature is raised to 200-400 ℃ in a muffle furnace and is kept for 1-5 h to completely decompose the citric acid, preferably the temperature is kept for 2-4 h at 300-400 ℃; preferably, the temperature is increased to 800-900 ℃ and the temperature is preserved for 3-5 h.
6. The method for preparing high-performance perovskite catalyst in-situ reduction Pt nanoparticles according to claim 1, wherein in step 3, the flow rate of the mixed gas of hydrogen and inert shielding gas is 15-30 mL/min; the inert protective gas is argon, nitrogen or helium.
7. The method for preparing Pt nanoparticles by in-situ reduction of a high-performance perovskite catalyst according to claim 1, wherein in step 3, the reduction temperature is preferably 350-400 ℃, and the holding treatment time is 1-5 hours, preferably 2-4 hours.
8. The perovskite catalyst produced by the production method as set forth in any one of claims 1 to 7, wherein the oxygen vacancy in the perovskite lattice is increased by reducing Pt from the lattice to the surface by a reducing gas to form Pt nanoparticles.
9. The perovskite catalyst of claim 8, wherein the perovskite catalyst has the formula LaCo1- xPtxO3And x is greater than zero and equal to or less than 0.1.
10. Use of the perovskite catalyst prepared by the preparation method according to any one of claims 1 to 7 in the purification of diesel engine exhaust, characterized in that the perovskite catalyst is used for the catalytic oxidation of soot particulates in diesel engine exhaust.
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CN113332992A (en) * 2021-05-31 2021-09-03 华中科技大学 Perovskite catalyst and preparation method thereof
CN113991088A (en) * 2021-10-29 2022-01-28 中国科学技术大学 Novel lithium ion battery cathode material and preparation method thereof
CN114832814A (en) * 2022-04-02 2022-08-02 中国科学院金属研究所 Method for preparing metal cocatalyst and perovskite metal oxide eutectic epitaxial growth
CN116613328A (en) * 2023-05-17 2023-08-18 东莞理工学院 PdPt bimetallic alloy electrode material and preparation method and application thereof

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