CN116020487A - Noble metal doped perovskite type oxide catalyst and preparation method thereof - Google Patents
Noble metal doped perovskite type oxide catalyst and preparation method thereof Download PDFInfo
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- 150000001768 cations Chemical class 0.000 claims description 2
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- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 9
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- 239000010936 titanium Substances 0.000 abstract 1
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 33
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- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 6
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- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 2
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- QGUAJWGNOXCYJF-UHFFFAOYSA-N cobalt dinitrate hexahydrate Chemical compound O.O.O.O.O.O.[Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O QGUAJWGNOXCYJF-UHFFFAOYSA-N 0.000 description 1
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- AOPCKOPZYFFEDA-UHFFFAOYSA-N nickel(2+);dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O AOPCKOPZYFFEDA-UHFFFAOYSA-N 0.000 description 1
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- HBEQXAKJSGXAIQ-UHFFFAOYSA-N oxopalladium Chemical compound [Pd]=O HBEQXAKJSGXAIQ-UHFFFAOYSA-N 0.000 description 1
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- 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
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- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention discloses a noble metal doped perovskite type oxide catalyst and a preparation method thereof, which is characterized in that the noble metal doped perovskite type oxide catalyst has a chemical formula (La 1‑x Ce x ) y M 0.99 Pt 0.01 O 3 Wherein M is one of Fe, mn, ni, co, x and y are molar values respectively, and x is more than or equal to 0 and less than or equal to 0.1,0.8 and y is more than or equal to 1; adopting perovskite structure with A-site defect, doping trace noble metal into B-site of perovskite, reducing by hydrogen gas, and passing through perovskiteThe rivet has the characteristics of stable titanium ore structure, and can be used for producing melted noble metal particles, so that the noble metal particles are prevented from being agglomerated and deactivated at high temperature. The perovskite type catalyst fully exerts respective advantages by combining perovskite type oxide with trace Pt, further reduces production cost, has high activity and good stability, has higher low-temperature activity, high-temperature sintering resistance and certain water and sulfur resistance, and is beneficial to clean emission of automobile exhaust.
Description
Technical Field
The invention belongs to the technical field of catalysts, and particularly relates to a noble metal doped perovskite type oxide catalyst and a preparation method thereof.
Background
With the progress of economy and society, the automobile industry is rapidly developed, and the number of automobiles is rapidly increased, so that the environmental pollution caused by automobile exhaust is also increasingly serious. The three-effect catalysis technology is the most main, most direct and most effective means for treating automobile exhaust. The three-effect catalysis technology uses the method for preparing three main pollutants CO and NO x HC and HC have catalytic combustion function, and a technology of complete or nearly complete conversion in a low-temperature section is realized.
The first generation of automobile exhaust gas purifying catalysts used in the 70 s of the last century were mainly platinum, palladium oxide type catalysts, which mainly catalyze the conversion of carbon monoxide and hydrocarbons in exhaust gas, and are also called "two-way catalysts" because they act only on carbon monoxide and hydrocarbons. However, with the improvement of environmental protection standards, new requirements are also put on the emission of nitrogen oxide in automobile exhaust, and at the moment, a three-way catalyst capable of simultaneously reducing the emission of nitrogen oxide is generated, which mainly comprises four parts of a cordierite ceramic carrier, a coating material, an auxiliary agent and an active component, wherein the active component mainly comprises noble metals Pt, rh, pd and the like, and the Pt is cheap and easily obtained compared with other metals, has higher catalytic oxidation performance and also has better sulfur poisoning resistance. However, the expensive high Wen Yishao junction is deactivated, so that reasonable optimization of the catalyst structure and the study of the interaction mechanism of the catalyst are one of main targets of research. Perovskite type oxides have good oxidation-reduction property, thermal stability and structural stability, so that the perovskite type oxides have good research prospects in tail gas treatment all the time.
Accordingly, in order to solve the above-mentioned problems, a noble metal doped perovskite-type oxide catalyst and a method for preparing the same are proposed herein.
Disclosure of Invention
In order to solve the technical problems, the invention designs the noble metal doped perovskite oxide catalyst and the preparation method thereof, and the perovskite oxide is combined with trace Pt to reduce the use amount of noble metal, so that the production cost is reduced, the prepared catalyst has high activity, good stability, higher low-temperature activity and high-temperature sintering resistance, and the required light-off temperature of the catalyst is low.
In order to achieve the technical effects, the invention is realized by the following technical scheme: a noble metal doped perovskite oxide catalyst is characterized in that the chemical formula is (La 1-x Ce x ) y M 0.99 Pt 0.01 O 3 Wherein M is one of Fe, mn, ni, co, x and y are molar values respectively, and x is more than or equal to 0 and less than or equal to 0.1,0.8 and y is more than or equal to 1; the catalyst is supported on the honeycomb ceramics by a carrier oxide.
Another object of the present invention is to provide a method for preparing a noble metal doped perovskite type oxide catalyst, characterized by comprising the steps of:
step1, respectively weighing/measuring lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, M metal nitrate aqueous solution and chloroplatinic acid solution according to a proportion, dissolving in deionized water, adding citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30-45 min;
step2, placing the mixture in a water bath environment with the temperature of 70-80 ℃ and stirring the mixture for 4-5 hours until the solution forms wet gel;
step3, placing the wet gel in a drying oven at 100-120 ℃ for drying for 12-15 hours to form xerogel;
step4, taking out xerogel, grinding, placing the powder in a muffle furnace, heating to 400-420 ℃ at a heating rate of 1-3 ℃/min, roasting for 2-3 hours, heating to 700-750 ℃ at a heating rate of 1-3 ℃/min, roasting for 4-6 hours, and heating to 500 ℃ and 10% H 2 、90％N 2 Under the condition thatReducing for 3-4 h to obtain (La) 1-x Ce x ) y M 0.99 Pt 0.01 O 3 Perovskite oxide powder;
step5, mixing aluminum oxide and perovskite oxide powder to prepare a solution, fully stirring, and ball-milling to prepare coating slurry;
step6, coating the coating slurry on the honeycomb ceramics, and drying and roasting to obtain the honeycomb ceramics.
Further, the ratio of the citric acid amount to the total metal cations in Step1 is 1:1.
further, the doping amount of the noble metal Pt is less than 1wt%.
Further, in Step5, the mass ratio of the alumina to the perovskite oxide powder is 9-10: 1, a step of; stirring time is 8-10 h, ball milling is 2-3 h.
Further, the Step6 coating adopts an upper coating vacuum suction mode, the coated honeycomb ceramic is dried for 2-4 hours at the temperature of 110-130 ℃, and then baked for 3-4 hours at the temperature of 500-600 ℃.
The beneficial effects of the invention are as follows:
according to the invention, research on doping noble metal into perovskite type oxide is carried out, less than 1wt% of Pt is doped into the B site of perovskite type oxide with A site defect, and then the noble metal is dissolved outwards through hydrogen reduction to obtain an elastic catalyst; by adjusting the reduction conditions, platinum nano particles with high catalytic activity are firmly embedded into the surface of perovskite, and a small amount of Ce is doped at the A site of the perovskite so as to improve the activity and sulfur resistance of the catalyst; the modified perovskite type catalyst is prepared by doping the A site and the B site, and the catalyst with optimal modified metal combination and proportion with high removal rate is preferable, so that the catalyst has important significance for treating automobile exhaust;
the perovskite and the trace Pt are combined to reduce the consumption of noble metal, so that the production cost is reduced, and the prepared catalyst has high activity, good stability, high low-temperature activity and high-temperature sintering resistance, and low ignition temperature.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a graph of the conversion of carbon monoxide over temperature for catalysts of the invention having different Ce ratios at the A site;
FIG. 2 is an XRD image of catalysts with different Ce proportions at the A-position;
FIG. 3 is a graph of the conversion of carbon monoxide over temperature for catalysts under different reduction conditions and at different ratios of A-site defects;
FIG. 4 is a graph showing the conversion of carbon monoxide by a catalyst of a different metal element at the B site as a function of temperature;
FIG. 5 is (La 0.97 Ce 0.03 ) 0.9 Co 0.99 Pt 0.01 O 3 An XRD image of (a);
FIG. 6 is (La 0.97 Ce 0.03 ) 0.9 Fe 0.99 Pt 0.01 O 3 An XRD image of (a);
FIG. 7 is (La 0.97 Ce 0.03 ) 0.9 Ni 0.99 Pt 0.01 O 3 Is a XRD pattern of (C).
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
La 0.97 Ce 0.03 MnO 3 Preparation of perovskite oxide: 4.2g of lanthanum nitrate hexahydrate, 0.13g of cerium nitrate hexahydrate and 3.58g of 50wt% of nitrate were weighed separatelyDissolving the manganese acid aqueous solution in 50ml of deionized water, adding 3.84g of citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30min; placing the mixture in a water bath environment at 70 ℃ and stirring the mixture for 4 to 5 hours until the solution forms wet gel; drying wet gel in a drying oven at about 110deg.C for 12 hr to form xerogel; taking out and grinding, placing the powder in a muffle furnace, heating to 400 ℃ at a temperature rising rate of 2 ℃ for roasting for 2 hours, and heating to 700 ℃ at a temperature rising rate of 2 ℃ for roasting for 4 hours to obtain La 0.97 Ce 0.03 MnO 3 Perovskite oxide powder.
Embodiment two:
La 0.97 Ce 0.03 Mn 0.99 Pt 0.01 O 3 preparation of perovskite oxide: 1g of chloroplatinic acid hexahydrate is dissolved in 250ml of deionized water and uniformly mixed to prepare a solution, 4.2g lanthanum nitrate hexahydrate, 0.13g cerium nitrate hexahydrate, 3.54g50wt% manganese nitrate aqueous solution and 6.4ml chloroplatinic acid solution are respectively weighed, dissolved in 50ml of deionized water, and after magnetic stirring is uniform, 3.84g citric acid is added for continuous magnetic stirring for 30min; placing the mixture in a water bath environment at 70 ℃ and stirring the mixture for 4 to 5 hours until the solution forms wet gel; drying wet gel in a drying oven at about 110deg.C for 12 hr to form xerogel; taking out and grinding, placing the powder in a muffle furnace, heating to 400 ℃ at a temperature rising rate of 2 ℃ for roasting for 2 hours, and heating to 700 ℃ at a temperature rising rate of 2 ℃ for roasting for 4 hours to obtain La 0.97 Ce 0.03 Mn 0.99 Pt 0.01 O 3 Perovskite oxide powder.
Embodiment III:
(1)(La 0.97 Ce 0.03 ) 0.9 Mn 0.99 Pt 0.01 O 3 preparation of perovskite oxide: respectively weighing 3.78g of lanthanum nitrate hexahydrate, 0.12g of cerium nitrate hexahydrate, 3.54g of 50wt% manganese nitrate aqueous solution and 6.4ml of chloroplatinic acid solution, dissolving in 50ml of deionized water, adding 3.84g of citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30min; placing the mixture in a water bath environment at 70 ℃ and stirring the mixture for 4 to 5 hours until the solution forms wet gel; drying wet gel in a drying oven at about 110deg.C for 12 hr to form xerogel; taking out, grinding, placing the powder in a muffle furnace, heating to 400 deg.C at 2 deg.C heating rate, roasting for 2 hr, heating to 700 deg.C at 2 deg.C heating rate, and roasting for 4 hr to obtain the final product (La) 0.97 Ce 0.03 ) 0.9 Mn 0.99 Pt 0.01 O 3 Perovskite oxide powder; at 500 ℃,10% H 2 、90％N 2 Reducing for 3h under the condition;
(2) Preparation of coating slurry: la is subjected to 0.97 Ce 0.03 MnO 3 Perovskite oxide powder and gamma-Al 2 O 3 According to the mass ratio of 1:9, mixing the materials in deionized water, continuously stirring for 8 hours, and ball-milling for 2 hours to prepare coating slurry;
(3) Coating and roasting: and (3) coating the slurry prepared in the step (2) on a cordierite honeycomb in a coating vacuum suction mode, drying at 120 ℃, and roasting in a muffle furnace at 550 ℃ for 3 hours to obtain the monolithic catalyst.
Embodiment four:
(1)(La 0.97 Ce 0.03 ) 0.9 Fe 0.99 Pt 0.01 O 3 preparation of perovskite oxide: respectively weighing 3.78g of lanthanum nitrate hexahydrate, 0.12g of cerium nitrate hexahydrate, 4.04g of ferric nitrate nonahydrate and 6.4ml of chloroplatinic acid solution, dissolving in 50ml of deionized water, adding 3.84g of citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30min; placing the mixture in a water bath environment at 70 ℃ and stirring the mixture for 4 to 5 hours until the solution forms wet gel; drying wet gel in a drying oven at about 110deg.C for 12 hr to form xerogel; taking out, grinding, placing the powder in a muffle furnace, heating to 400 deg.C at 2 deg.C heating rate, roasting for 2 hr, heating to 800 deg.C at 2 deg.C heating rate, roasting for 4 hr to obtain the final product (La) 0.97 Ce 0.03 ) 0.9 Fe 0.99 Pt 0.01 O 3 Perovskite oxide powder; at 500 ℃,10% H 2 、90％N 2 Reducing for 3h under the condition;
(2) Preparation of coating slurry: will (La) 0.97 Ce 0.03 ) 0.9 Fe 0.99 Pt 0.01 O 3 Perovskite oxide powder and gamma-Al 2 O 3 According to the mass ratio of 1:9, mixing the materials in deionized water, continuously stirring for 8 hours, and ball-milling for 2 hours to prepare coating slurry;
(3) Coating and roasting: and (3) coating the slurry prepared in the step (2) on a cordierite honeycomb in a coating vacuum suction mode, drying at 120 ℃, and roasting in a muffle furnace at 550 ℃ for 3 hours to obtain the monolithic catalyst.
Fifth embodiment:
(1)(La 0.97 Ce 0.03 ) 0.9 Co 0.99 Pt 0.01 O 3 preparation of perovskite oxide: respectively weighing 3.78g of lanthanum nitrate hexahydrate, 0.12g of cerium nitrate hexahydrate, 2.91g of cobalt nitrate hexahydrate and 6.4ml of chloroplatinic acid solution, dissolving in 50ml of deionized water, adding 3.84g of citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30min; placing the mixture in a water bath environment at 70 ℃ and stirring the mixture for 4 to 5 hours until the solution forms wet gel; drying wet gel in a drying oven at about 110deg.C for 12 hr to form xerogel; taking out, grinding, placing the powder in a muffle furnace, heating to 400 deg.C at 2 deg.C heating rate, roasting for 2 hr, heating to 800 deg.C at 2 deg.C heating rate, roasting for 4 hr to obtain the final product (La) 0.97 Ce 0.03 ) 0.9 Co 0.99 Pt 0.01 O 3 Perovskite oxide powder; at 500 ℃,10% H 2 、90％N 2 Reducing for 3h under the condition;
(2) Preparation of coating slurry: will (La) 0.97 Ce 0.03 ) 0.9 Co 0.99 Pt 0.01 O 3 Perovskite oxide powder and gamma-Al 2 O 3 According to the mass ratio of 1:9, mixing the materials in deionized water, continuously stirring for 8 hours, and ball-milling for 2 hours to prepare coating slurry;
(3) Coating and roasting: and (3) coating the slurry prepared in the step (2) on a cordierite honeycomb in a coating vacuum suction mode, drying at 120 ℃, and roasting in a muffle furnace at 550 ℃ for 3 hours to obtain the monolithic catalyst.
Example six:
(1)(La 0.97 Ce 0.03 ) 0.9 Ni 0.99 Pt 0.01 O 3 preparation of perovskite oxide: respectively weighing 3.78g of lanthanum nitrate hexahydrate, 0.12g of cerium nitrate hexahydrate, 2.91g of nickel nitrate hexahydrate and 6.4ml of chloroplatinic acid solution, dissolving in 50ml of deionized water, adding 3.84g of citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30min; placing the mixture in a water bath environment at 70 ℃ and stirring the mixture for 4 to 5 hours until the solution forms wet gel; placing wet gel at 110deg.CDrying in a left drying box and a right drying box for 12 hours to form xerogel; taking out, grinding, placing the powder in a muffle furnace, heating to 400 deg.C at 2 deg.C heating rate, roasting for 2 hr, heating to 800 deg.C at 2 deg.C heating rate, roasting for 4 hr to obtain the final product (La) 0.97 Ce 0.03 ) 0.9 Ni 0.99 Pt 0.01 O 3 Perovskite oxide powder; at 500 ℃,10% H 2 、90％N 2 Reducing for 3h under the condition;
(2) Preparation of coating slurry: will (La) 0.97 Ce 0.03 ) 0.9 Ni 0.99 Pt 0.01 O 3 Perovskite oxide powder and gamma-Al 2 O 3 According to the mass ratio of 1:9, mixing the materials in deionized water, continuously stirring for 8 hours, and ball-milling for 2 hours to prepare coating slurry;
(3) Coating and roasting: and (3) coating the slurry prepared in the step (2) on a cordierite honeycomb in a coating vacuum suction mode, drying at 120 ℃, and roasting in a muffle furnace at 550 ℃ for 3 hours to obtain the monolithic catalyst.
In the above examples, the support was selected from a cordierite honeycomb support having a specification of Φ110mm×80mm, a cell density of 600cpsi, a cell wall thickness of 4mil, and a volume of 0.76L. The catalyst loading was 180g/L.
The activity test method comprises the following steps:
the performance test of the catalyst is carried out in a fixed bed reactor of a tubular furnace, and the test is carried out by selecting the CO with the highest proportion in tail gas: CO1%, O210% and N2 are balance gas, and the airspeed is 60000h -1 The gas composition was analyzed by a smoke analyzer. Each catalyst was tested for its conversion to carbon monoxide as a function of temperature. T for converting carbon monoxide by catalysts prepared by different A-site Ce proportions 10 、T 50 And T 90 List, as shown in table one:
TABLE La 1-x Ce x MnO 3 T of (x= 0,0.03,0.05,0.07,0.1) 10 、T 50 And T 90
Firstly, laMnO with excellent catalytic activity and stability is selected 3 As perovskite matrix. The Ce is adopted to partially replace La at the A site of the perovskite-type metal oxide, and the sulfur resistance of the catalyst can be provided by increasing the oxygen vacancy of the catalyst and increasing the valence state of the B site metal element so as to improve the catalytic activity of lanthanum-based perovskite. Because the radius of Ce atom is larger than that of La atom, substituting La for Ce at A position can easily produce CeO in the process of catalyst formation 2 The impurity phase affects the judgment of the performance, and the substitution amount of Ce is not more than 10%. As is observed from the XRD pattern of FIG. 2, ceO does not appear during the doping of Ce at the A-position 2 Is all pure LaMnO 3 Perovskite phase. In the temperature programming process, the performance improvement is not increased with the increase of Ce substitution. Catalyst La with optimal performance 0.97 Ce 0.03 MnO 3 T 10 、T 50 And T 90 148.8 ℃,172.8 ℃ and 188.1 ℃ respectively. The temperature is improved by about 30 ℃ compared with the substrate.
TABLE II T of catalysts under different pretreatment conditions 10 、T 50 And T 90
From FIG. 3 and Table II, it can be found that there is little improvement in performance of the sample having no defective structure and subjected to hydrogen reduction (T 10 、T 50 、T 90 152 ℃, 185 ℃, 193 ℃ respectively. However, after the A-site defect and hydrogen reduction are designed, the catalytic activity is greatly improved, and the sample with the best performance (La 0.97 Ce 0.03 ) 0.9 Mn 0.99 Pt 0.01 O 3 Performance T of (2) 10 、T 50 、T 90 113 ℃, 134 ℃, 140 ℃ and T respectively 90 The temperature was raised by 53 ℃.
The catalytic performance of the perovskite on CO is observed by replacing different metal ions at the B site of the perovskite, and through FIG. 4, the best La-Mn expected effect can be seen, and the La-Co perovskite performance is not optimal. In the design of the ratio and experimental conditions (La 0.97 Ce 0.03 ) 0.9 Fe 0.99 Pt 0.01 O 3 The best catalytic combustion performance of CO is T 10 、T 50 、T 90 The catalyst has excellent low-temperature catalytic CO combustion performance at 74 ℃ and 98 ℃ and 113 ℃ respectively.
No Pt peak appears in all XRD images, probably the high dispersibility of Pt particles and the trace amount of Pt was not swept out. And no other hetero-peaks demonstrate that the doped element is fully incorporated into the perovskite phase.
Claims (6)
1. A noble metal doped perovskite oxide catalyst is characterized in that the chemical formula is (La 1-x Ce x ) y M 0.99 Pt 0.01 O 3 Wherein M is one of Fe, mn, ni, co, x and y are molar values respectively, and x is more than or equal to 0 and less than or equal to 0.1,0.8 and y is more than or equal to 1; the catalyst is supported on the honeycomb ceramics by a carrier oxide.
2. A method for preparing a noble metal doped perovskite oxide catalyst, which is characterized by comprising the following steps:
step1, respectively weighing/measuring lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, M metal nitrate aqueous solution and chloroplatinic acid solution according to a proportion, dissolving in deionized water, adding citric acid after magnetic stirring uniformly, and continuing magnetic stirring for 30-45 min;
step2, placing the mixture in a water bath environment with the temperature of 70-80 ℃ and stirring the mixture for 4-5 hours until the solution forms wet gel;
step3, placing the wet gel in a drying oven at 100-120 ℃ for drying for 12-15 hours to form xerogel;
step4, taking out xerogel, grinding, placing the powder in a muffle furnace, heating to 400-420 ℃ at a heating rate of 1-3 ℃/min, roasting for 2-3 hours, heating to 700-750 ℃ at a heating rate of 1-3 ℃/min, roasting for 4-6 hours, and heating to 500 ℃ and 10% H 2 、90％N 2 Reducing for 3-4 h under the condition to obtain (La) 1-x Ce x ) y M 0.99 Pt 0.01 O 3 Perovskite oxide powder;
step5, mixing aluminum oxide and perovskite oxide powder to prepare a solution, fully stirring, and ball-milling to prepare coating slurry;
step6, coating the coating slurry on the honeycomb ceramics, and drying and roasting to obtain the honeycomb ceramics.
3. The method for preparing a noble metal-doped perovskite-type oxide catalyst as claimed in claim 2, wherein: the ratio of the citric acid amount to the total metal cations in Step1 is 1:1.
4. the method for preparing a noble metal-doped perovskite-type oxide catalyst as claimed in claim 2, wherein: the doping amount of the noble metal Pt is less than 1wt%.
5. The method for preparing a noble metal-doped perovskite-type oxide catalyst as claimed in claim 2, wherein: the mass ratio of the alumina to the perovskite oxide powder in Step5 is 9-10: 1, a step of; stirring time is 8-10 h, ball milling is 2-3 h.
6. The method for preparing a noble metal-doped perovskite-type oxide catalyst as claimed in claim 2, wherein: the Step6 coating adopts an upper coating vacuum suction mode, the coated honeycomb ceramic is dried for 2-4 hours at the temperature of 110-130 ℃, and then baked for 3-4 hours at the temperature of 500-600 ℃.
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