CN109589988A - The double coated catalysts of diesel engine based on hydrotalcite Derived Oxides and preparation method - Google Patents

The double coated catalysts of diesel engine based on hydrotalcite Derived Oxides and preparation method Download PDF

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CN109589988A
CN109589988A CN201811651436.1A CN201811651436A CN109589988A CN 109589988 A CN109589988 A CN 109589988A CN 201811651436 A CN201811651436 A CN 201811651436A CN 109589988 A CN109589988 A CN 109589988A
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catalyst coatings
catalyst
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CN109589988B (en
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吕刚
朱越
宋崇林
李亚松
张荣鑫
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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
    • B01J23/8986—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 manganese, technetium or rhenium
    • 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
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B01D53/9413—Processes characterised by a specific catalyst
    • B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
    • 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
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/04—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of alkali metals, alkaline earth metals or magnesium
    • B01J20/041—Oxides or hydroxides
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/012—Diesel engines and lean burn gasoline engines

Abstract

The present invention discloses a kind of double coated catalysts of the diesel engine based on hydrotalcite Derived Oxides and preparation method.External coating contains Pt and the main active constituent of perovskite；BaO adsorbent；Ce-Zr co-catalyst；Hydrotalcite Derived Oxides and γ-Al2O3Coating basic material；Inner coating contains the main active constituent of perovskite；BaO adsorbent；Ce-Zr co-catalyst；Hydrotalcite Derived Oxides, γ-Al2O3And SiO2Coating basic material；And cordierite honeycomb ceramic carrier.Preparation process includes: catalyst composition design；The preparation of perovskite and hydrotalcite Derived Oxides and the coating of inside and outside catalyst coatings.By the circulation change of dilute/fuel-rich operating condition of diesel engine, catalyst can in efficient catalytic exhaust NOx absorption-reduction purification reaction.Using non-homogeneous double coating productions, the distribution character of functional material is optimized, reduces cost of material, and improves NOx clean-up effect and endurance quality.

Description

The double coated catalysts of diesel engine based on hydrotalcite Derived Oxides and preparation method
Technical field
The invention belongs to exhaust gas from diesel vehicle pollutant purification technologies, and in particular to one kind is for nitrogen oxidation in exhaust gas from diesel vehicle Object (Nitrogen Oxides-NOx) pollutant absorption-reduction purification catalyst and preparation method thereof.
Background technique
Lean-burn NOx trap (Lean NOx Trap-LNT) technology is to control medium and small Diesel NOx discharge at present most to have One of method of effect has very high NOXTransformation efficiency is to guarantee diesel engine NOXDischarge reaches Europe V, VI emission regulation of Europe most Have one of the exhaust gas aftertreatment techniques of potentiality.LNT technology can pass through control under the action of dedicated absorption-reducing catalyst Diesel engine alternate cycles run lean-burn and fuel-rich two operating conditions to effectively remove the NOx in tail gas.Typically LNT technology is dedicated urges Agent (abbreviation LNT catalyst) is Pt/BaO/Al2O3/ ceramic monolith System Catalyst, wherein precious metals pt as it is main activity at Point, in Lean Burn Operating by the oxygen-enriched (O of diesel engine2) a part of NO in exhaust is catalytically oxidized to NO2, this part NO2With remaining NO Then adsorbed on the lnt catalyst in the form of nitrate/nitrites adsorbing species by BaO adsorbent.When being switched to richness When firing operating condition operation, O is practically free of in diesel exhaust gas at this time2, and hydrocarbon (HC), hydrogen (H2) etc. reproducibilities ingredient it is more, these Sexual element is restored under the main catalytic reactive component of LNT catalyst, is nitrogen by the NOx conversion of LNT catalyst adsorption state (N2), water (H2The innocuous substances such as O), realize the purification of NOx, meanwhile, BaO adsorbent has restored gaseous state after releasing ADSORPTION STATE NOx The adsorption capacity of NOx, that is, realize the regeneration of BaO adsorbent.But it will lead to urge as main active constituent using Pt completely Agent is with high costs, sulfur resistive and heat resistance are poor, and therefore, noble metal substitution becomes in novel LNT catalyst R&D work One of core content.And the coating property of BaO adsorbent is poor, the mass ratio of BaO is more than 20% just in general LNT catalyst Coating stability can be deteriorated, therefore, additive amount of the BaO in LNT catalyst needs stringent limitation, urges so as to cause traditional LNT The NOx absorption property of agent is difficult to improve.Al2O3The coating basic material in LNT catalyst, can based on active constituent, inhale Attached dose of equal ingredients provide the working surface of bigger serface, high stability.But Al2O3LNT catalytic activity and the NOx absorption of itself Performance is poor, is easy to happen phase transformation at high temperature or generates the BaAl of spinel structure with BaO sorbent reactions2O4, lead to NOx Store active bit-loss.Therefore, there is the coating basic material of additional adsorbent function also to become novel LNT catalyst and grind for research and development Send out an important content in work.
Perovskite composite oxide is a kind of efficient redox reaction catalyst, dirty in Vehicular internal combustion engine tail gas Contaminate object field of purification commercial applications.The material is often with ABO3It indicates, wherein by A biggish cations and B lesser sun Ion and certain amount of oxonium ion collectively constitute cubic crystal structure, and since A, B bit element therein is common metal Element, cost of material are far below precious metal material.Currently, lanthanum manganate (LaMnO3) it is one of most common perovskite material, And using is suitable for that part replaces A La elements and B Mn elements can be with the object of modulation perovskite material entirety to metallic element respectively Reason-chemical characteristic optimizes particular characteristic index.In addition, early-stage study shows to add a small amount of noble metal material in perovskite material Material can significantly improve perovskite material to the catalytic activity of oxidation-reduction reaction.
Derived Mixed Oxides (the Al that aluminium (Al)-magnesium (Mg) hydrotalcite-based compound is obtained through high-temperature roasting2O3· 6MgO), specific surface area with higher, stronger alkalinity, close to the unit NOx saturated extent of adsorption and excellent coating of BaO Performance has using it as the catalyst coat of coating basic material preparation close to Al2O3The specific surface area and machinery of base coating are strong Degree, and in the coating of LNT catalyst Al can be substituted with arbitrary proportion2O3.It is derivative using hydrotalcite in novel LNT catalyst Composite oxide material can provide additional adsorbent for LNT catalyst, improve LNT catalyst as coating basic material Whole NOx absorption property, can also reduce the dosage of BaO adsorbent.In addition, with Bi and Ni element, part substitutes hydrotalcite respectively Al and Mg element in Derived Mixed Oxides can be further improved hydrotalcite by the synergistic effect between Determination of multiple metal elements The NOx absorption property of Derived Mixed Oxides.
Traditional LNT catalyst prepares catalyst coatings, this method technique letter using the method for repeatedly applying identical coating paste It is single, but the function of LNT catalyst different depth coating is not identical, and the exhaust gas composition of processing is also different, uniform coating meeting The functional component of certain depths is caused to be distributed insufficient, and the functional component of certain depths is distributed surplus.Therefore, for urging Change response characteristic research and development non-uniform coating to be conducive to save the dosage of functional component while improving catalytic effect.
Summary of the invention
In conjunction with the prior art, the present invention is directed to the main active constituent of noble metal, modified hydrotalcite Derived Mixed Oxides coating The action characteristic of the functional components such as basic material, which designs the different catalyst coatings of two layers of composition, realizes high-performance LNT catalyst Performance optimization.The present invention provide it is a kind of suitable for diesel vehicle, with LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides It substitutes most of noble metal, substitute major part γ-Al with Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides2O3And it adopts With the novel LNT catalyst and preparation method thereof of non-homogeneous double catalyst coatings.
In order to solve the above technical problems, the present invention proposes a kind of double paintings of the diesel engine based on hydrotalcite Derived Oxides Layer catalyst, including two layers of catalyst coatings being sequentially coated in catalyst carrier, wherein apply urging on a catalyst support Change coating is interior catalyst coatings, coated on interior catalyst coatings, at the catalyst coatings different from interior catalyst coatings are grouped as be outer Catalyst coatings；The catalyst carrier is 400 mesh cordierite honeycomb ceramics；
The outer catalyst coatings include Pt, LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2- ZrO2Solid solution, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3；
The interior catalyst coatings include LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2-ZrO2Gu Solution, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2；
The LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, wherein x indicates two kinds of ions mole of Sr, La The molar percent ratio of La, x=25~75% in the sum of number；Y indicates moles hundred of Mn in the sum of two kinds of mole number of ions of Co, Mn Divide ratio, y=25~50%；Meanwhile the LaxSr(1-x)MnyCo(1-y)O3La ion and Sr in type perovskite composite oxides The ratio of the sum of molal quantity of ion and the sum of the molal quantity of Mn ion and Co ion is 1:1；
The Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides are by the part Bi substitution Al2O36MgO type class water Al in talcum Derived Mixed Oxides, by the part Ni substitution Al2O3Mg in 6MgO type houghite Derived Mixed Oxides And formed, wherein tetra- kinds of elements of Bi, Al, Ni, Mg are respectively with Bi2O3、Al2O3, NiO, MgO form to be dispersed in Bi-Ni bis- In metal-modified hydrotalcite Derived Mixed Oxides, and Bi2O3And Al2O3Molar percentage are as follows: 50~80%/50~20%, The sum of molar percentage is 100%；The molar percentage of NiO and MgO are as follows: 25~75%/75~25%, the sum of molar percentage It is 100%；And the sum of Bi ion and the molal quantity of Al ion in the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides With the ratio of the sum of the molal quantity of Ni ion and Mg ion are as follows: 1:3；
In the outer catalyst coatings, Pt and LaxSr(1-x)MnyCo(1-y)O3The outer catalysis of type perovskite composite oxides composition applies The main active constituent of layer, and Pt and LaxSr(1-x)MnyCo(1-y)O3The mass percent of type perovskite composite oxides are as follows: 2~5%/ 98~95%, the sum of mass percent is 100%；Outer catalyst coatings adsorbent is formed by BaO, by CeO2-ZrO2Solid solution composition Outer catalyst coatings co-catalyst；By Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3The outer catalysis of composition applies Layer basic material, and the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Mass percent are as follows: 90%/10%；The main active constituent of the outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings co-catalyst and outer Catalyst coatings basic material has collectively constituted the outer catalyst coatings of catalyst, the main active constituent of China and foreign countries' catalyst coatings, outer catalysis The mass percent of coated adsorbent, outer catalyst coatings co-catalyst and outer catalyst coatings basic material respectively corresponds are as follows: 10~ 15%/10%/5~10%/75~65%, the sum of mass percent is 100%；
In the interior catalyst coatings, by LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form interior catalyst coatings Main active constituent；Interior catalyst coatings adsorbent is formed by BaO, by CeO2-ZrO2Solid solution forms interior catalyst coatings co-catalyst； By Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Catalyst coatings basic material in forming, and The Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Mass percent are as follows: 80~85%/ 10%/10~5%, the sum of mass percent is 100%；The main active constituent of the interior catalyst coatings, interior catalyst coatings adsorbent, Interior catalyst coatings co-catalyst and interior catalyst coatings basic material, have collectively constituted the interior catalyst coatings of catalyst, wherein interior urge Change the matter of the main active constituent of coating, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings basic material Amount percentage respectively corresponds are as follows: and 5~10%/10%/5~10%/80~70%, the sum of mass percent is 100%.
Further, the present invention is based on the double coated catalysts of the diesel engine of hydrotalcite Derived Oxides, wherein described CeO2-ZrO2CeO in solid solution2With ZrO2Mass percent are as follows: 80%/20%.
γ-the Al2O3It is converted by the Aluminum sol as adhesive coating；The SiO2By as adhesive coating Silica gel be converted into.
The mass percent of the outer catalyst coatings, interior catalyst coatings and catalyst carrier are as follows: 4~8%/12~18%/ 84~74%, the sum of mass percent is 100%.
The preparation method of the double coated catalysts of the above-mentioned diesel engine based on hydrotalcite Derived Oxides, comprising the following steps:
Step 1: catalyst composition design:
It separately designs: the LaxSr(1-x)MnyCo(1-y)O3La ion and Sr ion rubs in type perovskite composite oxides The molar percentage of that percentage, Mn ion and Co ion；In Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, Bi2O3And Al2O3Mole percent when NiO and MgO molar percentage；In the main active constituent of outer catalyst coatings Pt with LaxSr(1-x)MnyCo(1-y)O3The mass percent of type perovskite composite oxides；The main active constituent of outer catalyst coatings, outer catalysis The mass percent of coated adsorbent, outer catalyst coatings co-catalyst and outer catalyst coatings basic material；The outer catalyst coatings Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al in basic material2O3Mass percent；The interior catalysis The quality of the main active constituent of coating, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings basic material Percentage；Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al in the interior catalyst coatings basic material2O3With SiO2Mass percent；The mass percent range of the outer catalyst coatings, interior catalyst coatings and catalyst carrier；It is prepared Outer catalyst coatings slurry, which can prepare the quality of outer catalyst coatings and prepare interior catalyst coatings slurry, can prepare interior catalyst coatings Quality；
Step 2: LaxSr(1-x)MnyCo(1-y)O3The preparation of type perovskite composite oxides
Calculate what catalyst coatings and outer catalyst coatings in preparing needed according to the ratio for designing each component in step 1 LaxSr(1-x)MnyCo(1-y)O3The total mole number of type perovskite composite oxides and the wherein molal quantity of La, Sr, Mn and Co ion, According still further to 433.0g [La (NO3)3·6H2O] preparation 1mol La ion, 211.6g [Sr (NO3)2] preparation 1mol Sr ion, 245.1g[Mn(CH3COO)2·4H2O] preparation 1mol Mn ion, 291.1g [Co (NO3)2·6H2O] preparation 1mol Co ion Conversion scale and four kinds of raw materials total mole number and C6H12O6The ratio between molal quantity be 1:1 ratio and C6H12O6Point Son amount is 180.2, calculates preparation LaxSr(1-x)MnyCo(1-y)O3La (NO needed for type perovskite composite oxides3)3·6H2O、 Sr(NO3)2、Mn(CH3COO)2·4H2O、Co(NO3)2·6H2O、C6H12O6The quality of five kinds of raw materials；By above-mentioned La (NO3)3· 6H2O、Sr(NO3)2、Mn(CH3COO)2·4H2O、Co(NO3)2·6H2O、C6H12O6Five kinds of raw materials, according to every mole metal ion The ratio for being dissolved in 0.75~1L deionized water, which is added into deionized water, is configured to solution；On a rotary evaporator by the solution It is evaporated at 60~80 DEG C, until solution is transformed into honey shape wet gel；Again by the wet gel dry 6 at 80~110 DEG C ~12h obtains fluffy, frangible, faint yellow xerogel；The xerogel is warming up in Muffle furnace with the rate of 3 DEG C/min 400 DEG C and 2h is kept, 800 DEG C of roasting 3h are then warming up to the rate of 10 DEG C/min again, obtain LaxSr(1-x)MnyCo(1-y) O3Type perovskite composite oxides；
Step 3: the preparation of Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides:
It is calculated required for the interior catalyst coatings of preparation and outer catalyst coatings according to the ratio for designing each component in step 1 The gross mass of Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and wherein Bi2O3、Al2O3, NiO, MgO molal quantity, According still further to 970.1g [Bi (NO3)3·5H2O] preparation 1mol Bi2O3、750.2g[Al(NO3)3·9H2O] preparation 1mol Al2O3、 290.8g[Ni(NO3)2·6H2O] preparation 1mol NiO, 256.4g [Mg (NO3)2·6H2O] prepare the conversion scale of 1mol MgO Bi (NO needed for calculating preparation Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides3)3·5H2O、Al(NO3)3·9H2O、 Ni(NO3)2·6H2O、Mg(NO3)2·6H2The quality of tetra- kinds of raw materials of O；According to having determined that quality weighs the Bi (NO3)3· 5H2O、Al(NO3)3·9H2O、Ni(NO3)2·6H2O、Mg(NO3)2·6H2Tetra- kinds of raw materials of O, by four kinds of raw materials be added according to Every mole of Ni ion and every mole of Mg ion pair are answered in the weighed deionized water of the ratio of 0.5~1L deionized water, agitated to match Solution is made, is preceding body liquid；The NaOH and Na of sufficient amount are weighed again2CO3, and the molal quantity and Na of NaOH2CO3Molal quantity Ratio is 2:1, and the ratio of 1L deionized water is corresponded to according still further to every moles of NaOH, by the NaOH and Na2CO3It is added to deionization In water, it is sufficiently stirred until NaOH and Na2CO3It is completely dissolved, obtained solution is buffer；By buffer with 30~50ml/ The speed of min is added in precursor liquid, is vigorously stirred, meanwhile, the forerunner that buffer is being added continuously is measured with pH value analyzer The pH value of liquid；When pH value is between 9.5~10.5, stop that buffer is added, and continue 2~4h of stirring, still aging 24 ~48h filters the solid matter after isolating ageing in solution, rinses 3~5 times to solid matter deionized water, 90 Dry 8~16h at~110 DEG C, roasts 2~4h at 500~600 DEG C, and after natural cooling, it is ground 1h on ball mill, Obtain Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides；
Step 4: the preparation and coating of interior catalyst coatings:
La required for prepared by interior catalyst coatings is calculated according to the ratio for designing each component in step 1xSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2、ZrO2, the derivative combined oxidation of Bi-Ni bimetallic-modified hydrotalcite Object, γ-Al2O3、SiO2Quality；In conjunction with 255.4g [Ba (CH3COO)2] preparation 153.3g BaO, 434.1g [Ce (NO3)3· 6H2O] preparation 172.1g CeO2、429.3g[Zr(NO3)4·5H2O] preparation 123.2g ZrO2Conversion scale calculate preparation Ba (CH required for interior catalyst coatings3COO)2、Ce(NO3)3·6H2O、Zr(NO3)4·5H2The quality of O；According still further in Aluminum sol Al2O3With SiO in silica gel2Mass percent calculate separately out the matter for preparing consumption Aluminum sol and silica gel needed for interior catalyst coatings Amount；In addition, according further in every 100g catalyst coatings need 5~15g average molecular weight be 20000 polyethylene glycol and 25~ The ratio of 50g nitric acid calculates the quality of the polyethylene glycol and nitric acid that consume needed for catalyst coatings in preparing；According to having determined that matter Amount weighs Ba (CH3COO)2、Ce(NO3)3·6H2O、Zr(NO3)4·5H2O, Aluminum sol, silica gel, average molecular weight are 20000 Polyethylene glycol, nitric acid and LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides and Bi-Ni bimetallic-modified hydrotalcite spread out Whole raw materials are added to quality and are equivalent to and plan to prepare interior 10~15 times of gross mass of catalyst coatings by raw composite oxides Deionized water in, be sufficiently stirred to form uniform suspension；By the suspension be ground on wet grinding mill in position grain Diameter is in 1.0~1.2 micron ranges, then the suspension after grinding stirs to 16 at 60~80 DEG C~for 24 hours to get to interior Catalyst coatings slurry；According to the mass percent of the interior catalyst coatings, outer catalyst coatings and catalyst carrier are as follows: 4~8%/ 12~18%/84~74%, the sum of mass percent is 100%；Catalyst coatings are matched with 400 mesh cordierite honeycomb ceramics in carrying out Material, and impregnated as follows, drying and calcination processing: the 400 mesh cordierite honeycomb ceramics carriers for having determined that quality are weighed, by institute It states ceramic monolith to be immersed in 60~80 DEG C of the interior catalyst coatings slurry, promotes all holes full of carrier naturally to slurry Behind road, carrier is taken out from slurry, blows residual fluid in duct off, dry 6~12h at 90~110 DEG C, then 500~ 2~4h is roasted at 600 DEG C；The coating of interior catalyst coatings is completed in the above-mentioned dipping of repetition, drying and roasting process 2 times；
Step 5: the preparation and coating of outer catalyst coatings:
Pt, La required for prepared by outer catalyst coatings are calculated according to the ratio for designing each component in step 1xSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2、ZrO2, the derivative combined oxidation of Bi-Ni bimetallic-modified hydrotalcite Object, γ-Al2O3Quality；In conjunction with 517.9g [H2PtCl6·6H2O] preparation 195.1g Pt, 255.4g Ba (CH3COO)2Preparation 153.3g BaO、434.1g Ce(NO3)3·6H2O prepares 172.1g CeO2、429.3g Zr(NO3)4·5H2O prepares 123.2g ZrO2Conversion scale calculate H required for the outer catalyst coatings of preparation2PtCl6·6H2O、Ba(CH3COO)2、Ce(NO3)3· 6H2O、Zr(NO3)4·5H2The quality of O；According still further to Al in Aluminum sol2O3Mass percent calculate the outer catalyst coatings institute of preparation The quality of Aluminum sol need to be consumed；In addition, according further to catalyst coatings outside every 100g need 5~15g average molecular weight be 20000 it is poly- The ratio of ethylene glycol and 25~50g nitric acid calculates the matter of the polyethylene glycol and nitric acid that consume needed for preparing outer catalyst coatings Amount；According to having determined that quality weighs the preparation of outer catalyst coatings and use H2PtCl6·6H2O、Ba(CH3COO)2、Ce(NO3)3·6H2O、Zr (NO3)4·5H2O, Aluminum sol, polyethylene glycol, nitric acid and La that average molecular weight is 20000xSr(1-x)MnyCo(1-y)O3Type calcium titanium Mine composite oxides and Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, and whole raw materials are added to quality It is equivalent to and plans in outer 10~15 times of catalyst coatings gross mass of the deionized water of preparation, be sufficiently stirred uniformly suspended to be formed Liquid；The suspension is ground to median to be in 1.0~1.2 micron ranges on wet grinding mill, it then will grinding Suspension afterwards stirs 16 at 60~80 DEG C~for 24 hours to get to outer catalyst coatings slurry；Step 5 has been applied interior catalysis to apply 400 mesh cordierite honeycomb ceramics carriers of layer are immersed in 60~80 DEG C of the outer catalyst coatings slurry, are mentioned naturally to slurry After rising all ducts full of carrier, carrier is taken out from slurry, blows residual fluid in duct off, done at 90~110 DEG C Dry 6~12h, then 2~4h is roasted at 500~600 DEG C；The coating for completing outer catalyst coatings, has finally obtained based on neatly The double coated catalysts of the diesel engine of stone Derived Oxides.
The double coated catalysts of diesel engine based on hydrotalcite Derived Oxides made from above-mentioned preparation method are packaged, And the catalyst after encapsulation is installed in the exhaust duct of diesel engine, by NOx absorption-reduction reaction purification diesel engine exhaust NOx pollutant.
Compared with prior art, the beneficial effects of the present invention are:
The present invention substitutes most of noble metal in traditional LNT catalyst with substituted type perovskite composite oxides, is dropping While low cost of material, the sulfur resistance and thermal stability of novel LNT catalyst are improved.Meanwhile being spread out with modified hydrotalcite Raw composite oxides substitute most of Al in traditional LNT catalyst2O3, significantly improve the NOx adsorption capacity of LNT catalyst. And in modified hydrotalcite Derived Mixed Oxides Bi element to Al element and Ni element to the substitution of Mg element, optimize hydrotalcite The NOx absorption property of Derived Mixed Oxides is especially especially apparent the promotion effect of low temperature NOx absorption property.In addition, this Invention LNT catalyst uses non-homogeneous double coating productions, optimizes the distribution character of functional material, new further decreasing While type LNT catalyst cost of material, improve catalyst NOx clean-up effect and durable, unfailing performance.
Detailed description of the invention
Fig. 1 is LNT catalyst NOx purifying property engine evaluation system schematic diagram.
Wherein: 1- dynamometer machine；2- shaft coupling；3- tests diesel engine；4- inlet air flow meter；5- air inlet air conditioning；6- fuel injector； 7- fuel injection control systems；8- exhaust sampling port A；9- temperature sensor A；10- is vented voltage-stablizer；11- temperature sensor B； 12-LNT catalyst converter；13- temperature sensor C；14- exhaust sampling port B；15- exhaust gas sampling channel；The analysis of 16- engine exhaust Instrument；17- air pump.
Fig. 2 is to utilize the LNT catalyst NOx purifying property engine evaluation system, is vented in diesel engine Lean Burn Operating Temperature is 250 DEG C, air speed 30000h-1Steady state condition when, the lower diesel engine of Examples 1 to 3 prepared catalyst catalysis is arranged In gas NOx absorption-reduction reaction, the purification efficiency of NOx.
Fig. 3 is to utilize the LNT catalyst NOx purifying property engine evaluation system, is vented in diesel engine Lean Burn Operating Temperature is 350 DEG C, air speed 50000h-1Steady state condition when, the lower diesel engine of Examples 1 to 3 prepared catalyst catalysis is arranged In gas NOx absorption-reduction reaction, the purification efficiency of NOx.
Fig. 4 is to be recycled using the LNT catalyst NOx purifying property engine evaluation system in European steady state test Diesel engine when (European steady state cycle-ESC) is tested, under the catalysis of Examples 1 to 3 prepared catalyst It is vented in NOx absorption-reduction reaction, the purification efficiency of NOx.
Specific embodiment
The present invention is based on the double coated catalysts of the diesel engine of hydrotalcite Derived Oxides, including are sequentially coated at catalyst load Two layers of catalyst coatings on body, wherein the catalyst coatings applied on a catalyst support are interior catalyst coatings, are coated in interior catalysis It is outer catalyst coatings on coating, at the catalyst coatings different from interior catalyst coatings are grouped as；The catalyst carrier is 400 mesh violets Green stone ceramic honey comb.The outer catalyst coatings include Pt, LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2-ZrO2Solid solution, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3；The interior catalyst coatings packet Include LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2-ZrO2Solid solution, Bi-Ni bimetallic-modified neatly Stone Derived Mixed Oxides, γ-Al2O3And SiO2。
(1) LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, wherein x indicates that two kinds of ions of Sr, La rub The molar percent ratio of La, x=25~75% in the sum of your number；Y indicates mole of Mn in the sum of two kinds of mole number of ions of Co, Mn Percentage, y=25~50%；Meanwhile the LaxSr(1-x)MnyCo(1-y)O3In type perovskite composite oxides La ion and The ratio of the sum of molal quantity of Sr ion and the sum of the molal quantity of Mn ion and Co ion is 1:1.
(2) the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides are by the part Bi substitution Al2O36MgO type Al in houghite Derived Mixed Oxides, by the part Ni substitution Al2O3In 6MgO type houghite Derived Mixed Oxides Mg and formed, wherein tetra- kinds of elements of Bi, Al, Ni, Mg are respectively with Bi2O3、Al2O3, NiO, MgO form be dispersed in Bi- In Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, and Bi2O3And Al2O3Molar percentage are as follows: 50~80%/50~ 20%, the sum of molar percentage is 100%；The molar percentage of NiO and MgO are as follows: 25~75%/75~25%, Mole percent Than the sum of be 100%；And in the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides Bi ion and Al ion mole Ratio of the sum of the number with the sum of the molal quantity of Ni ion and Mg ion are as follows: 1:3；
(3) by precious metals pt and the LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form outer catalyst coatings Main active constituent, and the Pt and LaxSr(1-x)MnyCo(1-y)O3The mass percent of type perovskite composite oxides are as follows: 2~ 5%/98~95%, the sum of mass percent is 100%.Outer catalyst coatings adsorbent is formed by BaO, by CeO2-ZrO2Solid solution Form outer catalyst coatings co-catalyst.By Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Composition is outer to urge Change coating basic material, and the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Mass percent Are as follows: 90%/10%.The main active constituent of the outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings co-catalyst and Outer catalyst coatings basic material collectively constitutes the outer catalyst coatings of catalyst of the present invention, wherein the main activity of outer catalyst coatings The mass percent difference of ingredient, outer catalyst coatings adsorbent, outer catalyst coatings co-catalyst and outer catalyst coatings basic material It is corresponding are as follows: 10~15%/10%/5~10%/75~65%, the sum of mass percent is 100%.
(4) by LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form the main active constituent of interior catalyst coatings, by BaO forms interior catalyst coatings adsorbent, by CeO2-ZrO2Solid solution forms interior catalyst coatings co-catalyst.By Bi-Ni bimetallic Modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Catalyst coatings basic material in forming, and the bis- gold of the Bi-Ni Belong to modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Mass percent are as follows: 80~85%/10%/10~5%, The sum of mass percent is 100%.The main active constituent of the interior catalyst coatings, interior catalyst coatings adsorbent, interior catalyst coatings help Catalyst and interior catalyst coatings basic material, collectively constitute the interior catalyst coatings of catalyst of the present invention, wherein interior catalyst coatings master The mass percent point of catalyst, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings basic material Dui Ying not are as follows: 5~10%/10%/5~10%/80~70%, the sum of mass percent is 100%.
(5) CeO2-ZrO2CeO in solid solution2With ZrO2Mass percent are as follows: 80%/20%.
(6) γ-Al2O3It is converted by the Aluminum sol as adhesive coating；The SiO2By being bonded as coating The silica gel of agent is converted into.
(7) catalyst of the present invention is formed by the interior catalyst coatings, outer catalyst coatings and 400 mesh cordierite honeycomb ceramics, Wherein, 400 mesh cordierite honeycomb ceramics are the carrier of catalyst of the present invention, and need to apply interior catalyst coatings and outer catalysis Layer is coated on the 400 mesh cordierite honeycomb ceramics carrier, and the outer catalyst coatings, interior catalyst coatings and 400 mesh violets are green The mass percent of stone honeycomb ceramic carrier are as follows: 4~8%/12~18%/84~74%, the sum of mass percent is 100%.
The preparation method of the double coated catalysts of diesel engine based on hydrotalcite Derived Oxides, including following 5 steps: (1) catalyst composition design；(2)LaxSr(1-x)MnyCo(1-y)O3The preparation of type perovskite composite oxides；(3) the bis- gold of Bi-Ni Belong to the preparation of modified hydrotalcite Derived Mixed Oxides；(4) preparation and coating of interior catalyst coatings；(5) system of outer catalyst coatings Standby and coating.
Below by way of specific embodiment and in conjunction with attached drawing, technical solution of the present invention will be further described.It needs Bright be the embodiment be it is narrative, and non-limiting, the content that is covered of the present invention is not limited to following embodiments.
The double coated catalysts of diesel engine based on hydrotalcite Derived Oxides include two kinds of catalyst coatings, wherein being directly coated with Catalyst coatings on 400 mesh cordierite honeycomb ceramics carriers are interior catalyst coatings, and are coated on interior catalyst coatings, at grouping It is outer catalyst coatings at the catalyst coatings different from interior catalyst coatings.Outer catalyst coatings include precious metals pt, LaxSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2-ZrO2Solid solution, Bi-Ni bimetallic-modified hydrotalcite derivative are compound Oxide, γ-Al2O3；Interior catalyst coatings include LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2- ZrO2Solid solution, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3、SiO2；Catalyst of the present invention also wraps Include 400 mesh cordierite honeycomb ceramics carriers.
By precious metals pt and LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form the outer main activity of catalyst coatings Ingredient, and Pt and LaxSr(1-x)MnyCo(1-y)O3The mass percent of type perovskite composite oxides are as follows: 2~5%/98~ 95%, the sum of mass percent is 100%.Outer catalyst coatings adsorbent is formed by BaO, by CeO2-ZrO2Solid solution composition is outer to urge Change coating co-catalyst.By Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Form outer catalyst coatings base Plinth material, and the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Mass percent are as follows: 90%/ 10%.The main active constituent of the outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings co-catalyst and outer catalysis apply Layer basic material, collectively constitutes the outer catalyst coatings of catalyst of the present invention, and the main active constituent of China and foreign countries' catalyst coatings, outer catalysis apply The mass percent of layer adsorbent, outer catalyst coatings co-catalyst and outer catalyst coatings basic material respectively corresponds are as follows: 10~ 15%/10%/5~10%/75~65%, the sum of mass percent is 100%.
By LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form the main active constituent of interior catalyst coatings, by BaO Catalyst coatings adsorbent in forming, by CeO2-ZrO2Solid solution forms interior catalyst coatings co-catalyst.By Bi-Ni bimetallic-modified Hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Catalyst coatings basic material in forming, and the Bi-Ni bimetallic changes Property hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Mass percent are as follows: 80~85%/10%/10~5%, quality The sum of percentage is 100%.The main active constituent of the interior catalyst coatings, interior catalyst coatings adsorbent, interior catalyst coatings co-catalysis Agent and interior catalyst coatings basic material, collectively constitute the interior catalyst coatings of catalyst of the present invention, wherein the main activity of interior catalyst coatings The mass percent difference of ingredient, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings basic material It is corresponding are as follows: 5~10%/10%/5~10%/80~70%, the sum of mass percent is 100%.
The LaxSr(1-x)MnyCo(1-y)O3The molar percentage of La ion and Sr ion in type perovskite composite oxides Are as follows: 25~75%/75~25%, the sum of molar percentage is 100%；The molar percentage of Mn ion and Co ion are as follows: 25~ 50%/75~50%, the sum of molar percentage is 100%；Meanwhile the LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxygen The ratio of the sum of molal quantity of La ion and Sr ion and the sum of the molal quantity of Mn ion and Co ion in compound are as follows: 1:1.
The CeO2-ZrO2CeO in solid solution2With ZrO2Mass percent are as follows: 80%/20%.
In the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides tetra- kinds of elements of Bi, Al, Ni, Mg respectively with Bi2O3、Al2O3, NiO, MgO form be dispersed in Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, and Bi2O3With Al2O3Molar percentage are as follows: 50~80%/50~20%, the sum of molar percentage be 100%；The Mole percent of NiO and MgO Than are as follows: 25~75%/75~25%, the sum of molar percentage is 100%；And the Bi-Ni bimetallic-modified hydrotalcite is derivative The ratio of the sum of molal quantity of Bi ion and Al ion and the sum of the molal quantity of Ni ion and Mg ion in composite oxides are as follows: 1: 3。
γ-the Al2O3It is converted by the Aluminum sol as adhesive coating；The SiO2By as adhesive coating Silica gel be converted into.
Catalyst of the present invention is formed by the interior catalyst coatings, outer catalyst coatings and 400 mesh cordierite honeycomb ceramics, In, 400 mesh cordierite honeycomb ceramics are the carrier of catalyst of the present invention, and are needed interior catalyst coatings and outer catalyst coatings Coated on the 400 mesh cordierite honeycomb ceramics carrier, and the outer catalyst coatings, interior catalyst coatings and 400 mesh cordierites The mass percent of honeycomb ceramic carrier are as follows: 4~8%/12~18%/84~74%, the sum of mass percent is 100%.
Below by way of the preparation method of specific embodiment the present invention will be described in detail catalyst.
Embodiment 1
(1) catalyst composition design
Separately design Pt and La in the main active constituent of catalyst coatings outxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxygen The mass percent of compound are as follows: 2%/98%；The main active constituent of outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings The mass percent of co-catalyst and outer catalyst coatings basic material are as follows: 15%/10%/10%/65%；Interior catalyst coatings basis Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al in material2O3And SiO2Mass percent are as follows: 85%/ 10%/5%；The main active constituent of interior catalyst coatings, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings The mass percent of basic material are as follows: 10%/10%/10%/70%；LaxSr(1-x)MnyCo(1-y)O3Type perovskite combined oxidation The molar percentage of La ion and Sr ion in object are as follows: 75%/25%, the molar percentage of Mn ion and Co ion are as follows: 50%/ 50%；In Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, Bi2O3And Al2O3Molar percentage are as follows: 80%/ The molar percentage of 20% and NiO and MgO are as follows: 25%/75%.Outer catalyst coatings, interior catalyst coatings and 400 mesh cordierite honeycombs The mass percent range of ceramic monolith are as follows: 7~8%/17~18%/76~74%.Preparing outer catalyst coatings slurry can make It the outer catalyst coatings of standby 2000g and prepares interior catalyst coatings slurry and can prepare catalyst coatings in 2000g.
(2)LaxSr(1-x)MnyCo(1-y)O3The preparation of type perovskite composite oxides
Weigh 694.6g La (NO3)3·6H2O、113.2g Sr(NO3)2、262.1g Mn(CH3COO)2·4H2O、 311.3g Co(NO3)2·6H2O and 770.9g C6H12O6, 5 kinds of raw materials are added together in 4L deionized water be configured to it is molten Liquid.The solution is evaporated at 80 DEG C on a rotary evaporator, it, will be described until the solution is transformed into honey shape wet gel Wet gel dry 6h at 110 DEG C, obtains faint yellow xerogel.By the xerogel with the rate of 3 DEG C/min in Muffle furnace It is warming up to 400 DEG C and keeps 2h, then 800 DEG C of roasting 3h are warming up to the rate of 10 DEG C/min, can be prepared by LaxSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides.
(3) preparation of Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides
Weigh 2667.4g Bi (NO3)3·5H2O、515.7g Al(NO3)3·9H2O、1499.2g Ni(NO3)2·6H2O、 3965.6g Mg(NO3)2·6H24 kinds of raw materials are added in 12L deionized water O, agitated to be configured to solution, are preceding body Liquid.200g NaOH and 265g Na are weighed again2CO3, will described two raw materials be added 5L deionized water in, be sufficiently stirred until NaOH and Na2CO3It is completely dissolved, is buffer.Then buffer is added in precursor liquid with the speed of 50ml/min, is acutely stirred It mixes, meanwhile, the pH value that the precursor liquid of buffer is being added continuously is measured with pH value analyzer；At pH value to the precursor liquid When between 9.5~10.5, stop that buffer is added, and precursor liquid is continued to stir 2h；By the forerunner after the completion of the stirring Liquid is still aging for 24 hours, has a large amount of solid matters to generate in forerunner's liquid container after ageing.Forerunner's liquid container is isolated by filtering In solid matter, then by the solid matter with deionized water rinse 3 times；By the solid matter after the flushing at 110 DEG C Lower dry 8h, then the solid matter after drying is roasted into 2h at 600 DEG C, the solid matter natural cooling after roasting, by its 1h is ground on ball mill, and Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides can be obtained.
(4) preparation and its coating of interior catalyst coatings
Al in the used Aluminum sol of embodiment 12O3Mass percentage be 10.8%, SiO in silica gel2Quality percentage Content is 25%.Weigh 200g LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, 333.2g Ba (CH3COO)2、 403.6g Ce(NO3)3·6H2O、139.4g Zr(NO3)4·5H2O, 1190g Bi-Ni bimetallic-modified hydrotalcite derivative is compound Oxide, 1296.3g Aluminum sol, 280g silica gel, the polyethylene glycol that 300g average molecular weight is 20000,500g nitric acid, will be described Whole raw materials are added in 20000g deionized water, are sufficiently stirred to form uniform suspension.The suspension is ground in wet process It is ground to median (D50 partial size) on grinding machine to be in 1.0~1.2 micron ranges, then by the suspension after grinding 80 16h is stirred at DEG C to get interior catalyst coatings slurry is arrived.400 mesh cordierite honeycomb ceramics carrier of 1000g is weighed, by the carrier Be immersed in 80 DEG C of the interior catalyst coatings slurry, after slurry promotes all ducts full of carrier naturally, by carrier from It is taken out in slurry, blows residual fluid in duct off, the dry 6h at 110 DEG C, then 2h is roasted at 600 DEG C.The above-mentioned dipping of repetition, Drying is with roasting process 2 times, i.e., the preparation of catalyst coatings in completion.
(5) preparation and coating of outer catalyst coatings
Weigh 15.9g H2PtCl6·6H2O、294g LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, 333.2g Ba(CH3COO)2、403.6g Ce(NO3)3·6H2O、139.4g Zr(NO3)4·5H2O, 1170g Bi-Ni bimetallic Modified hydrotalcite Derived Mixed Oxides, 1203.7g Aluminum sol, the polyethylene glycol that 300g average molecular weight is 20000,1000g Nitric acid, and whole raw materials are added in 20000g deionized water, it is sufficiently stirred to form uniform suspension.It will be described outstanding Turbid is ground to D50 partial size on wet grinding mill and is in 1.0~1.2 micron ranges, by the suspension after grinding at 80 DEG C Lower stirring 16h to get arrive outer catalyst coatings slurry.400 mesh cordierite honeycomb ceramics for having applied interior catalyst coatings are carried Body is immersed in 80 DEG C of the outer catalyst coatings slurry, after slurry promotes all ducts full of carrier naturally, by carrier It is taken out from slurry, blows residual fluid in duct off, the dry 6h at 110 DEG C, then 2h is roasted at 600 DEG C, that is, complete outer urge Change the preparation and coating of coating.
Embodiment 2
(1) catalyst composition design
Separately design Pt and La in the main active constituent of catalyst coatings outxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxygen The mass percent of compound are as follows: 5%/95%；The main active constituent of outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings The mass percent of co-catalyst and outer catalyst coatings basic material are as follows: 10%/10%/5%/75%.Interior catalyst coatings basis Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al in material2O3And SiO2Mass percent are as follows: 80%/ 10%/10%；The main active constituent of interior catalyst coatings, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalysis apply The mass percent of layer basic material are as follows: 5%/10%/5%/80%.LaxSr(1-x)MnyCo(1-y)O3Type perovskite combined oxidation The molar percentage of La ion and Sr ion in object are as follows: 25%/75%, the molar percentage of Mn ion and Co ion are as follows: 25%/ 75%.In Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, Bi2O3And Al2O3Molar percentage are as follows: 50%/ The molar percentage of 50% and NiO and MgO are as follows: 75%/25%.Outer catalyst coatings, interior catalyst coatings and 400 mesh cordierite honeycombs The mass percent range of ceramic monolith are as follows: 4~5%/17~18%/79~77%.Preparing outer catalyst coatings slurry can make It the outer catalyst coatings of standby 2000g and prepares interior catalyst coatings slurry and can prepare catalyst coatings in 2000g.
(2)LaxSr(1-x)MnyCo(1-y)O3The preparation of type perovskite composite oxides
Weigh 152.2g La (NO3)3·6H2O、223.1g Sr(NO3)2、86.2g Mn(CH3COO)2·4H2O、307.0g Co(NO3)2·6H2O and 506.7g C6H12O6, 5 kinds of raw materials are added together in 2.5L deionized water and are configured to solution.It will The solution evaporates at 60 DEG C on a rotary evaporator, then will be described until the solution is transformed into honey shape wet gel Wet gel dry 12h at 80 DEG C, obtains faint yellow xerogel.By the xerogel with the rate of 3 DEG C/min in Muffle furnace It is warming up to 400 DEG C and keeps 2h, then 800 DEG C of roasting 3h are warming up to the rate of 10 DEG C/min, can be prepared by LaxSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides.
(3) preparation of Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides
Weigh 1874.2g Bi (NO3)3·5H2O、1449.4g Al(NO3)3·9H2O、5056.4g Ni(NO3)2· 6H2O、1486.1g Mg(NO3)2·6H24 kinds of raw materials are added in 15L deionized water O, agitated to be configured to solution, are Preceding body liquid.200g NaOH and 265g Na are weighed again2CO3, described two raw materials are added in 5L deionized water, are sufficiently stirred straight To NaOH and Na2CO3It is completely dissolved, is buffer.Then buffer is added in precursor liquid with the speed of 30ml/min, acutely Stirring, meanwhile, the pH value that the precursor liquid of buffer is being added continuously is measured with pH value analyzer；PH value to the precursor liquid When between 9.5~10.5, stop that buffer is added, and precursor liquid is continued to stir 4h；Before after the completion of the stirring The still aging 48h of liquid is driven, there are a large amount of solid matters to generate in forerunner's liquid container after ageing.Precursor liquid appearance is isolated by filtering Solid matter in device, then solid matter deionized water is rinsed 5 times.By the solid matter after the flushing at 90 DEG C Lower dry 16h, then the solid matter after drying is roasted into 4h at 500 DEG C, the solid matter natural cooling after roasting, by its 1h is ground on ball mill, and Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides can be obtained.
(4) preparation and its coating of interior catalyst coatings
Al in the used Aluminum sol of embodiment 22O3Mass percentage be 10.8%, SiO in silica gel2Quality percentage Content is 25%.Weigh 100g LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, 333.2g Ba (CH3COO)2、 201.8g Ce(NO3)3·6H2O、69.7g Zr(NO3)4·5H2O, 1280g Bi-Ni bimetallic-modified hydrotalcite derivative is compound Oxide, 1481.5g Aluminum sol, 640g silica gel, the polyethylene glycol that 200g average molecular weight is 20000,1000g nitric acid, by institute It states whole raw materials to be added in 20000g deionized water, be sufficiently stirred to form uniform suspension.By the suspension in wet process It is ground to D50 partial size on grinder to be in 1.0~1.2 micron ranges, the suspension after grinding is stirred for 24 hours at 60 DEG C, Obtain interior catalyst coatings slurry.400 mesh cordierite honeycomb ceramics carrier of 1000g is weighed, the carrier is immersed in 60 DEG C In the interior catalyst coatings slurry, after slurry promotes all ducts full of carrier naturally, carrier is taken out from slurry, is blown Fall residual fluid in duct, the dry 12h at 90 DEG C, then 4h is roasted at 500 DEG C；It repeats above-mentioned dipping, drying and roasted Journey 2 times, that is, complete the preparation of interior catalyst coatings.
(5) preparation and coating of outer catalyst coatings
Weigh 190g LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, 26.5g H2PtCl6·6H2O、 333.2g Ba(CH3COO)2、201.8g Ce(NO3)3·6H2O、69.7g Zr(NO3)4·5H2O, 1350g Bi-Ni bimetallic Modified hydrotalcite Derived Mixed Oxides, 1388.9g Aluminum sol, the polyethylene glycol that 100g average molecular weight is 20000,1000g Nitric acid, and whole raw materials are added in 30000g deionized water, it is sufficiently stirred to form uniform suspension.It will be described outstanding Turbid is ground to D50 partial size on wet grinding mill and is in 1.0~1.2 micron ranges, by the suspension after grinding at 60 DEG C It is lower stirring for 24 hours to get arrive outer catalyst coatings slurry.400 mesh cordierite honeycomb ceramics for having applied interior catalyst coatings are carried Body is immersed in 80 DEG C of the outer catalyst coatings slurry, after slurry promotes all ducts full of carrier naturally, by carrier It is taken out from slurry, blows residual fluid in duct off, the dry 12h at 90 DEG C, then 4h is roasted at 500 DEG C, that is, complete outer urge Change the preparation and coating of coating.
Embodiment 3
(1) catalyst composition design
Separately design Pt and La in the main active constituent of catalyst coatings outxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxygen The mass percent of compound are as follows: 5%/95%；The main active constituent of outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings The mass percent of co-catalyst and outer catalyst coatings basic material are as follows: 15%/10%/5%/70%；Interior catalyst coatings basis Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al in material2O3And SiO2Mass percent are as follows: 85%/ 10%/5%；The main active constituent of interior catalyst coatings, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings The mass percent of basic material are as follows: 10%/10%/10%/70%；LaxSr(1-x)MnyCo(1-y)O3Type perovskite combined oxidation The molar percentage of La ion and Sr ion in object are as follows: 50%/50%, the molar percentage of Mn ion and Co ion are as follows: 50%/ 50%；In Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, Bi2O3And Al2O3Molar percentage are as follows: 50%/ The molar percentage of 50% and NiO and MgO are as follows: 50%/50%.Outer catalyst coatings, interior catalyst coatings and 400 mesh cordierite honeycombs The mass percent range of ceramic monolith are as follows: 6~7%/15~16%/79~77%.Preparing outer catalyst coatings slurry can make It the outer catalyst coatings of standby 2000g and prepares interior catalyst coatings slurry and can prepare catalyst coatings in 2000g.
(2)LaxSr(1-x)MnyCo(1-y)O3The preparation of type perovskite composite oxides
Weigh 481.3g La (NO3)3·6H2O、235.2g Sr(NO3)2、272.4g Mn(CH3COO)2·4H2O、 323.6g Co(NO3)2·6H2O and 801.2g C6H12O6, 5 kinds of raw materials are added together in 3.5L deionized water and are configured to Solution.The solution is evaporated at 70 DEG C on a rotary evaporator, until the solution is transformed into honey shape wet gel, by institute Wet gel dry 8h at 90 DEG C is stated, faint yellow xerogel is obtained.By the xerogel with the rate of 3 DEG C/min in Muffle furnace It is warming up to 400 DEG C and keeps 2h, then 800 DEG C of roasting 3h are warming up to the rate of 10 DEG C/min, can be prepared by LaxSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides.
(3) preparation of Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides
Weigh 1889.3g Bi (NO3)3·5H2O、1461.0g Al(NO3)3·9H2O、3398.0g Ni(NO3)2· 6H2O、2996.0g Mg(NO3)2·6H24 kinds of raw materials are added in 15L deionized water O, agitated to be configured to solution, are Preceding body liquid.200g NaOH and 265g Na are weighed again2CO3, described two raw materials are added in 5L deionized water, are sufficiently stirred straight To NaOH and Na2CO3It is completely dissolved, is buffer.Then buffer is added in precursor liquid with the speed of 40ml/min, acutely Stirring, meanwhile, the pH value that the precursor liquid of buffer is being added continuously is measured with pH value analyzer；PH value to the precursor liquid When between 9.5~10.5, stop that buffer is added, and precursor liquid is continued to stir 3h；Before after the completion of the stirring The still aging 36h of liquid is driven, there are a large amount of solid matters to generate in forerunner's liquid container after ageing.Precursor liquid appearance is isolated by filtering Solid matter in device, then solid matter deionized water is rinsed 4 times；By the solid matter after the flushing 100 Dry 12h at DEG C, then the solid matter after drying is roasted into 2h at 600 DEG C, the solid matter natural cooling after roasting, by it 1h is ground on ball mill, and Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides can be obtained.
(4) preparation and its coating of interior catalyst coatings
Al in the used Aluminum sol of embodiment 32O3Mass percentage be 10.8%, SiO in silica gel2Quality percentage Content is 25%.Weigh 200g LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, 333.2g Ba (CH3COO)2、 403.6g Ce(NO3)3·6H2O、139.4g Zr(NO3)4·5H2O, 1190g Bi-Ni bimetallic-modified hydrotalcite derivative is compound Oxide, 1296.3g Aluminum sol, 280g silica gel, the polyethylene glycol that 200g average molecular weight is 20000,500g nitric acid, will be described Whole raw materials are added in 25000g deionized water, are sufficiently stirred to form uniform suspension.The suspension is ground in wet process It is ground to D50 partial size on grinding machine to be in 1.0~1.2 micron ranges, the suspension after grinding is stirred into 20h at 70 DEG C, i.e., Obtain interior catalyst coatings slurry.400 mesh cordierite honeycomb ceramics carrier of 1000g is weighed, the carrier is immersed in 70 DEG C of institute It states in interior catalyst coatings slurry, after slurry promotes all ducts full of carrier naturally, carrier is taken out from slurry, is blown off Residual fluid in duct, the dry 9h at 100 DEG C, then 4h is roasted at 500 DEG C.Repeat above-mentioned dipping, drying and roasting process 2 It is secondary, that is, complete the preparation of interior catalyst coatings.
(5) preparation and its coating of outer catalyst coatings
Weigh 39.8g H2PtCl6·6H2O、285g LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, 333.2g Ba(CH3COO)2、201.8g Ce(NO3)3·6H2O、69.7g Zr(NO3)4·5H2O, 1260g Bi-Ni bimetallic Modified hydrotalcite Derived Mixed Oxides, 1296.3g Aluminum sol, the polyethylene glycol that 300g average molecular weight is 20000,1000g Nitric acid, and whole raw materials are added in 26000g deionized water, it is sufficiently stirred to form uniform suspension.It will be described outstanding Turbid is ground to D50 partial size on wet grinding mill and is in 1.0~1.2 micron ranges, by the suspension after grinding at 70 DEG C Lower stirring 20h to get arrive outer catalyst coatings slurry.400 mesh cordierite honeycomb ceramics for having applied interior catalyst coatings are carried Body is immersed in 70 DEG C of the outer catalyst coatings slurry, after slurry promotes all ducts full of carrier naturally, by carrier It is taken out from slurry, blows residual fluid in duct off, the dry 9h at 100 DEG C, then 2h is roasted at 600 DEG C, that is, complete outer urge Change the preparation and coating of coating.
It is made to the Examples 1 to 3 using LNT catalyst NOx purifying property engine evaluation system shown in FIG. 1 Diesel exhaust gas NOx absorption-reduction purification performance of standby catalyst is evaluated.It needs to urge prepared by Examples 1 to 3 before test Agent is respectively cut, is respectively combined into 4L integral catalyzer, and seals to the cutting, the integral catalyzer being combined into Dress processing.Test method are as follows:
(1) steady state condition is tested: using dynamometer machine 1 and 2 Control experiment engine of shaft coupling (CY4102 diesel engine) 3 Torque and revolving speed, and reach stable state using the temperature and humidity that air inlet air conditioning 5 adjusts engine charge, successively adjustment is started The ratio of machine extraction flow and catalyst volume is respectively 30000h-1And 50000h-1, and successively control 12 center of LNT catalyst converter The temperature of point is respectively 250 DEG C and 350 DEG C, carries out catalyst n Ox absorption-reduction reaction catalytically active assessment.In test, pass through Fuel injection control systems 7 adjust fuel injector 6 to the delivery rate of diesel engine, realize in diesel engine operational process, lean-burn/fuel-rich The switching of operating condition.The exhaust that diesel engine in-cylinder combustion is formed adsorb-go back into LNT catalyst converter after being vented voltage-stablizer 10 Former purified treatment.LNT catalyst converter handles forward and backward diesel exhaust gas and passes through respectively from exhaust sampling port A8 and exhaust sampling port B14 Exhaust gas sampling channel 15 enters engine exhaust analyzer 16 and carries out NOx concentration analysis, and the gas after NOx is analyzed passes through gas Pump 17 gives off laboratory.The delivery temperature of 10 front and back of temperature sensor A9 and temperature sensor B11 measurement exhaust voltage-stablizer, and The temperature at temperature sensor C13 measurement LNT catalyst converter center.The measured temperature and inlet air flow meter 4 of 3 temperature sensors Charge flow rate measured value provide feedback parameter for the control strategy of fuel injection control systems and dynamometer machine.Utilize the LNT Catalyst n Ox purifying property engine evaluation system, diesel engine Lean Burn Operating delivery temperature be 250 DEG C, air speed 30000h-1 When and Lean Burn Operating delivery temperature be 350 DEG C, air speed 50000h-1When, under the catalysis of Examples 1 to 3 prepared catalyst In diesel exhaust gas NOx absorption-reduction reaction, the purification efficiency difference of NOx is as shown in Figures 2 and 3.
(2) ESC is tested: using the LNT catalyst NOx purifying property engine evaluation system, and according to national standards GB 17691-2005 " automobile-used compression-ignited, gaseous fuel spark-ignition engine and automobile exhaust pollutant discharge limit value and measurement side Method (Chinese III, IV, V stage) " specified in ESC testing regulations evaluation Examples 1 to 3 prepared catalyst catalysis under bavin Oil machine is vented the clean-up effect of NOx in NOx absorption-reduction reaction, as shown in Figure 4.
To sum up, the invention discloses a kind of double coated catalysts of diesel engine based on hydrotalcite Derived Oxides and preparation sides Method.The outer catalyst coatings of catalyst contain Pt and the main active constituent of perovskite composite oxide；BaO adsorbent；CeO2-ZrO2It helps Catalyst；Modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Coating basic material；It is multiple that interior catalyst coatings contain Ca-Ti ore type Close oxidation owner's active constituent；BaO adsorbent；CeO2-ZrO2Co-catalyst；Modified hydrotalcite Derived Mixed Oxides, γ- Al2O3And SiO2Coating basic material；And 400 mesh cordierite honeycomb ceramics carrier.Preparation process includes: that catalyst composition is set Meter；LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides and Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides Preparation and inside and outside catalyst coatings preparation and coating.Pass through the circulation change of dilute/fuel-rich operating condition of diesel engine, catalyst energy The absorption of NOx-reduction purification reaction in enough efficient catalytic exhausts.The present invention substitutes tradition LNT with perovskite composite oxide Most of noble metal in catalyst improves the sulfur resistance and heat of novel LNT catalyst while reducing cost of material Stability.Meanwhile most of Al in traditional LNT catalyst is substituted with modified hydrotalcite Derived Mixed Oxides2O3, significantly mention The high NOx adsorption capacity of LNT catalyst.In addition, LNT catalyst of the present invention uses non-homogeneous double coating productions, optimization The distribution character of functional material while further decreasing novel LNT catalyst cost of material improves catalyst NOx clean-up effect and durable, unfailing performance.
Although above in conjunction with attached drawing, invention has been described, and the invention is not limited to above-mentioned specific implementations Mode, the above mentioned embodiment is only schematical, rather than restrictive, and those skilled in the art are at this Under the enlightenment of invention, without deviating from the spirit of the invention, many variations can also be made, these belong to of the invention Within protection.

Claims (6)

1. a kind of double coated catalysts of diesel engine based on hydrotalcite Derived Oxides, it is characterised in that: including being sequentially coated at Two layers of catalyst coatings in catalyst carrier, wherein the catalyst coatings applied on a catalyst support are interior catalyst coatings, coating It is outer catalyst coatings on interior catalyst coatings, at the catalyst coatings different from interior catalyst coatings are grouped as；
The catalyst carrier is 400 mesh cordierite honeycomb ceramics；
The outer catalyst coatings include Pt, LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2-ZrO2Gu Solution, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3；
The interior catalyst coatings include LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2-ZrO2Solid solution Body, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2；
The LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides, wherein x indicates the sum of two kinds of mole number of ions of Sr, La The molar percent ratio of middle La, x=25~75%；Y indicates the molar percentage of Mn in the sum of two kinds of mole number of ions of Co, Mn Example, y=25~50%；Meanwhile the LaxSr(1-x)MnyCo(1-y)O3La ion and Sr ion in type perovskite composite oxides The sum of molal quantity and the ratio of the sum of the molal quantity of Mn ion and Co ion be 1:1；
The Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides are by the part Bi substitution Al2O36MgO type houghite Al in Derived Mixed Oxides, by the part Ni substitution Al2O3Mg and shape in 6MgO type houghite Derived Mixed Oxides At, wherein tetra- kinds of elements of Bi, Al, Ni, Mg are respectively with Bi2O3、Al2O3, NiO, MgO form be dispersed in Bi-Ni bimetallic In modified hydrotalcite Derived Mixed Oxides, and Bi2O3And Al2O3Molar percentage are as follows: 50~80%/50~20%, mole The sum of percentage is 100%；The molar percentage of NiO and MgO are as follows: 25~75%/75~25%, the sum of molar percentage is 100%；And in the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides the sum of molal quantity of Bi ion and Al ion with The ratio of the sum of the molal quantity of Ni ion and Mg ion are as follows: 1:3；
In the outer catalyst coatings, Pt and LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form outer catalyst coatings master Active constituent, and Pt and LaxSr(1-x)MnyCo(1-y)O3The mass percent of type perovskite composite oxides are as follows: 2~5%/98~ 95%, the sum of mass percent is 100%；Outer catalyst coatings adsorbent is formed by BaO, by CeO2-ZrO2Solid solution composition is outer to urge Change coating co-catalyst；By Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Form outer catalyst coatings base Plinth material, and the Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al2O3Mass percent are as follows: 90%/ 10%；The main active constituent of the outer catalyst coatings, outer catalyst coatings adsorbent, outer catalyst coatings co-catalyst and outer catalysis apply Layer basic material, has collectively constituted the outer catalyst coatings of catalyst, and the main active constituent of China and foreign countries' catalyst coatings, outer catalyst coatings are inhaled Attached dose, the mass percent of outer catalyst coatings co-catalyst and outer catalyst coatings basic material respectively corresponds are as follows: 10~15%/ 10%/5~10%/75~65%, the sum of mass percent is 100%；
In the interior catalyst coatings, by LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides form the main work of interior catalyst coatings Property ingredient；Interior catalyst coatings adsorbent is formed by BaO, by CeO2-ZrO2Solid solution forms interior catalyst coatings co-catalyst；By Bi- Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Catalyst coatings basic material in forming, and it is described Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3And SiO2Mass percent are as follows: 80~85%/ 10%/10~5%, the sum of mass percent is 100%；The main active constituent of the interior catalyst coatings, interior catalyst coatings adsorbent, Interior catalyst coatings co-catalyst and interior catalyst coatings basic material, have collectively constituted the interior catalyst coatings of catalyst, wherein interior urge Change the matter of the main active constituent of coating, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings basic material Amount percentage respectively corresponds are as follows: and 5~10%/10%/5~10%/80~70%, the sum of mass percent is 100%.
2. the double coated catalysts of diesel engine according to claim 1 based on hydrotalcite Derived Oxides, it is characterised in that: institute State CeO2-ZrO2CeO in solid solution2With ZrO2Mass percent are as follows: 80%/20%.
3. the double coated catalysts of diesel engine according to claim 1 based on hydrotalcite Derived Oxides, it is characterised in that: institute State γ-Al2O3It is converted by the Aluminum sol as adhesive coating；The SiO2By the silica gel conversion as adhesive coating It generates.
4. the double coated catalysts of the diesel engine described in accordance with the claim 1 based on hydrotalcite Derived Oxides, it is characterised in that: The mass percent of the outer catalyst coatings, interior catalyst coatings and catalyst carrier are as follows: 4~8%/12~18%/84~74%, The sum of mass percent is 100%.
5. a kind of preparation method of the double coated catalysts of diesel engine based on hydrotalcite Derived Oxides, it is characterized in that: include with Lower step:
Step 1: catalyst composition design:
It is separately designed according to claim 1: the LaxSr(1-x)MnyCo(1-y)O3La ion and Sr in type perovskite composite oxides The molar percentage of the molar percentage of ion, Mn ion and Co ion；Bi-Ni bimetallic-modified hydrotalcite derives combined oxidation In object, Bi2O3And Al2O3Mole percent when NiO and MgO molar percentage；In the main active constituent of outer catalyst coatings Pt and LaxSr(1-x)MnyCo(1-y)O3The mass percent of type perovskite composite oxides；It is the main active constituent of outer catalyst coatings, outer The mass percent of catalyst coatings adsorbent, outer catalyst coatings co-catalyst and outer catalyst coatings basic material；The outer catalysis Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides and γ-Al in coating basic material2O3Mass percent；In described The main active constituent of catalyst coatings, interior catalyst coatings adsorbent, interior catalyst coatings co-catalyst and interior catalyst coatings basic material Mass percent；Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-in the interior catalyst coatings basic material Al2O3And SiO2Mass percent；The mass percent range of the outer catalyst coatings, interior catalyst coatings and catalyst carrier； Prepare outer catalyst coatings slurry can prepare the quality of outer catalyst coatings and in preparing catalyst coatings slurry can prepare in urge Change the quality of coating；
Step 2: LaxSr(1-x)MnyCo(1-y)O3The preparation of type perovskite composite oxides
Calculate what catalyst coatings and outer catalyst coatings in preparing needed according to the ratio for designing each composition in step 1 LaxSr(1-x)MnyCo(1-y)O3The total mole number of type perovskite composite oxides and the wherein molal quantity of La, Sr, Mn and Co ion, According still further to 433.0g [La (NO3)3·6H2O] preparation 1mol La ion, 211.6g [Sr (NO3)2] preparation 1mol Sr ion, 245.1g[Mn(CH3COO)2·4H2O] preparation 1mol Mn ion, 291.1g [Co (NO3)2·6H2O] preparation 1mol Co ion Conversion scale and four kinds of raw materials total mole number and C6H12O6The ratio between molal quantity be 1:1 ratio and C6H12O6Point Son amount is 180.2, calculates preparation LaxSr(1-x)MnyCo(1-y)O3La (NO needed for type perovskite composite oxides3)3·6H2O、 Sr(NO3)2、Mn(CH3COO)2·4H2O、Co(NO3)2·6H2O、C6H12O6The quality of five kinds of raw materials；
By above-mentioned La (NO3)3·6H2O、Sr(NO3)2、Mn(CH3COO)2·4H2O、Co(NO3)2·6H2O、C6H12O6Five kinds of originals Material, is added into deionized water according to the ratio that every mole metal ion is dissolved in 0.75~1L deionized water and is configured to solution；It will The solution evaporates at 60~80 DEG C on a rotary evaporator, until solution is transformed into honey shape wet gel；It again will be described wet Gel dry 6~12h at 80~110 DEG C, obtains fluffy, frangible, faint yellow xerogel；By the xerogel in Muffle furnace 400 DEG C are warming up to the rate of 3 DEG C/min and keeps 2h, 800 DEG C of roasting 3h are then warming up to the rate of 10 DEG C/min again, i.e., La is madexSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides；
Step 3: the preparation of Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides:
Bi-Ni required for the interior catalyst coatings of preparation and outer catalyst coatings is calculated according to the ratio for designing each component in step 1 The gross mass of bimetallic-modified hydrotalcite Derived Mixed Oxides and wherein Bi2O3、Al2O3, NiO, MgO molal quantity, according still further to 970.1g[Bi(NO3)3·5H2O] preparation 1mol Bi2O3、750.2g[Al(NO3)3·9H2O] preparation 1mol Al2O3、290.8g [Ni(NO3)2·6H2O] preparation 1mol NiO, 256.4g [Mg (NO3)2·6H2O] conversion scale for preparing 1mol MgO calculates Bi (NO needed for preparing Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides3)3·5H2O、Al(NO3)3·9H2O、Ni (NO3)2·6H2O、Mg(NO3)2·6H2The quality of tetra- kinds of raw materials of O；According to having determined that quality weighs the Bi (NO3)3·5H2O、 Al(NO3)3·9H2O、Ni(NO3)2·6H2O、Mg(NO3)2·6H2Four kinds of raw materials are added according to often rubbing tetra- kinds of raw materials of O That Ni ion and every mole of Mg ion pair are answered in the weighed deionized water of the ratio of 0.5~1L deionized water, agitated to be configured to Solution is preceding body liquid；
The NaOH and Na of sufficient amount are weighed again2CO3, and the molal quantity and Na of NaOH2CO3Molal quantity ratio be 2:1, according still further to Every moles of NaOH corresponds to the ratio of 1L deionized water, by the NaOH and Na2CO3Be added into deionized water, be sufficiently stirred until NaOH and Na2CO3It is completely dissolved, obtained solution is buffer；
Buffer is added in precursor liquid with the speed of 30~50ml/min, is vigorously stirred, meanwhile, it is continuously surveyed with pH value analyzer The pH value of the precursor liquid of buffer is being added in amount；When pH value is between 9.5~10.5, stopping addition buffer, and after Continuous stirring 2~4h, still aging 24~48h, filter the solid matter after isolating ageing in solution, spend to the solid matter Ionized water rinses 3~5 times, dry 8~16h at 90~110 DEG C, 2~4h of roasting at 500~600 DEG C, after natural cooling, It is ground to 1h on ball mill to get Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides are arrived；
Step 4: the preparation and coating of interior catalyst coatings:
La required for prepared by interior catalyst coatings is calculated according to the ratio for designing each component in step 1xSr(1-x)MnyCo(1-y)O3 Type perovskite composite oxides, BaO, CeO2、ZrO2, Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, γ-Al2O3、 SiO2Quality；In conjunction with 255.4g [Ba (CH3COO)2] preparation 153.3g BaO, 434.1g [Ce (NO3)3·6H2O] preparation 172.1g CeO2、429.3g[Zr(NO3)4·5H2O] preparation 123.2g ZrO2Conversion scale calculate preparation in catalyst coatings Required Ba (CH3COO)2、Ce(NO3)3·6H2O、Zr(NO3)4·5H2The quality of O；According still further to Al in Aluminum sol2O3And silica gel Middle SiO2Mass percent calculate separately out the quality for preparing consumption Aluminum sol and silica gel needed for interior catalyst coatings；In addition, also The ratio for the polyethylene glycol and 25~50g nitric acid that 5~15g average molecular weight is 20000 is needed according to catalyst coatings in every 100g Example calculates the quality of the polyethylene glycol and nitric acid that consume needed for catalyst coatings in preparing；According to having determined that quality weighs Ba (CH3COO)2、Ce(NO3)3·6H2O、Zr(NO3)4·5H2O, Aluminum sol, silica gel, average molecular weight be 20000 polyethylene glycol, Nitric acid and LaxSr(1-x)MnyCo(1-y)O3Type perovskite composite oxides and the derivative combined oxidation of Bi-Ni bimetallic-modified hydrotalcite Whole raw materials are added to quality and are equivalent to and plans the deionized waters of interior 10~15 times of gross mass of the catalyst coatings of preparation by object In, it is sufficiently stirred to form uniform suspension；By the suspension be ground on wet grinding mill median be in 1.0~ In 1.2 micron ranges, then the suspension after grinding stirs to 16 at 60~80 DEG C~it is starched for 24 hours to get to interior catalyst coatings Material；
According to the mass percent of the interior catalyst coatings, outer catalyst coatings and catalyst carrier are as follows: 4~8%/12~18%/ 84~74%, the sum of mass percent is 100%；Catalyst coatings and 400 mesh cordierite honeycomb ceramics ingredients in carrying out, and carry out Following dipping, drying and calcination processing:
The 400 mesh cordierite honeycomb ceramics carriers for having determined that quality are weighed, the ceramic monolith is immersed in 60~80 DEG C of institute It states in interior catalyst coatings slurry, after slurries promote all ducts full of carrier naturally, carrier is taken out from slurry, is blown off Residual fluid in duct, dry 6~12h at 90~110 DEG C, then 2~4h is roasted at 500~600 DEG C；
The coating of interior catalyst coatings is completed in the above-mentioned dipping of repetition, drying and roasting process 2 times；
Step 5: the preparation and coating of outer catalyst coatings:
Pt, La required for prepared by outer catalyst coatings are calculated according to the ratio for designing each component in step 1xSr(1-x) MnyCo(1-y)O3Type perovskite composite oxides, BaO, CeO2、ZrO2, the derivative combined oxidation of Bi-Ni bimetallic-modified hydrotalcite Object, γ-Al2O3Quality；In conjunction with 517.9g [H2PtCl6·6H2O] preparation 195.1g Pt, 255.4g Ba (CH3COO)2Preparation 153.3g BaO、434.1g Ce(NO3)3·6H2O prepares 172.1g CeO2、429.3g Zr(NO3)4·5H2O prepares 123.2g ZrO2Conversion scale calculate H required for the outer catalyst coatings of preparation2PtCl6·6H2O、Ba(CH3COO)2、Ce(NO3)3· 6H2O、Zr(NO3)4·5H2The quality of O；According still further to Al in Aluminum sol2O3Mass percent calculate the outer catalyst coatings institute of preparation The quality of Aluminum sol need to be consumed；In addition, according further to catalyst coatings outside every 100g need 5~15g average molecular weight be 20000 it is poly- The ratio of ethylene glycol and 25~50g nitric acid calculates the matter of the polyethylene glycol and nitric acid that consume needed for preparing outer catalyst coatings Amount；According to having determined that quality weighs the preparation of outer catalyst coatings and use H2PtCl6·6H2O、Ba(CH3COO)2、Ce(NO3)3·6H2O、Zr (NO3)4·5H2O, Aluminum sol, polyethylene glycol, nitric acid and La that average molecular weight is 20000xSr(1-x)MnyCo(1-y)O3Type calcium titanium Mine composite oxides and Bi-Ni bimetallic-modified hydrotalcite Derived Mixed Oxides, and whole raw materials are added to quality It is equivalent to and plans in outer 10~15 times of catalyst coatings gross mass of the deionized water of preparation, be sufficiently stirred uniformly suspended to be formed Liquid；The suspension is ground to median to be in 1.0~1.2 micron ranges on wet grinding mill, it then will grinding Suspension afterwards stirs 16 at 60~80 DEG C~for 24 hours to get to outer catalyst coatings slurry；
The 400 mesh cordierite honeycomb ceramics carriers that step 5 has applied interior catalyst coatings are immersed in 60~80 DEG C described outer to urge Change in coating paste, after slurry promotes all ducts full of carrier naturally, carrier is taken out from slurry, is blown off in duct Residual fluid, dry 6~12h at 90~110 DEG C, then 2~4h is roasted at 500~600 DEG C；Complete outer catalyst coatings Coating has finally obtained the double coated catalysts of the diesel engine based on hydrotalcite Derived Oxides.
6. the purposes of the double coated catalysts of a kind of diesel engine based on hydrotalcite Derived Oxides, it is characterized in that: by claim 5 The double coated catalysts of diesel engine based on hydrotalcite Derived Oxides made from the preparation method are packaged, and will be after encapsulation Catalyst be installed in the exhaust duct of diesel engine, pass through the NOx pollution in NOx absorption-reduction reaction purification diesel engine exhaust Object.
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CN111841572A (en) * 2020-08-06 2020-10-30 合肥神舟催化净化器股份有限公司 High-acidity single-coating perovskite-based ammonia oxidation catalyst for diesel engine and preparation and application methods thereof
CN112076741A (en) * 2020-09-18 2020-12-15 宁夏大学 Novel CeO2/Bi2O4Composite visible light catalyst and preparation method thereof
CN112076741B (en) * 2020-09-18 2023-04-14 宁夏大学 CeO (CeO) 2 /Bi 2 O 4 Composite visible light catalyst and preparation method thereof
CN112221511A (en) * 2020-10-13 2021-01-15 天津大学 Ternary metal oxide based diesel particulate oxidation catalyst and preparation method thereof
CN112221511B (en) * 2020-10-13 2022-07-19 天津大学 Ternary metal oxide based diesel particulate oxidation catalyst and preparation method thereof

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