CN111974390B - Catalyst for diesel vehicle tail gas and preparation process and application thereof - Google Patents

Catalyst for diesel vehicle tail gas and preparation process and application thereof Download PDF

Info

Publication number
CN111974390B
CN111974390B CN202010848605.1A CN202010848605A CN111974390B CN 111974390 B CN111974390 B CN 111974390B CN 202010848605 A CN202010848605 A CN 202010848605A CN 111974390 B CN111974390 B CN 111974390B
Authority
CN
China
Prior art keywords
slurry
oxide
catalyst
water
salt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010848605.1A
Other languages
Chinese (zh)
Other versions
CN111974390A (en
Inventor
樊蓉蓉
李兆强
王艳
张丞
王雨
丁智勇
王荣
郭欣
康娜
刘威
宋静
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Baotou Rare Earth Research Institute
Ruike Rare Earth Metallurgy and Functional Materials National Engineering Research Center Co Ltd
Original Assignee
Baotou Rare Earth Research Institute
Ruike Rare Earth Metallurgy and Functional Materials National Engineering Research Center Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Baotou Rare Earth Research Institute, Ruike Rare Earth Metallurgy and Functional Materials National Engineering Research Center Co Ltd filed Critical Baotou Rare Earth Research Institute
Priority to CN202010848605.1A priority Critical patent/CN111974390B/en
Publication of CN111974390A publication Critical patent/CN111974390A/en
Application granted granted Critical
Publication of CN111974390B publication Critical patent/CN111974390B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/652—Chromium, molybdenum or tungsten
    • B01J23/6527—Tungsten
    • 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
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
    • 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
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0213—Preparation of the impregnating solution
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/082—Decomposition and pyrolysis
    • B01J37/088—Decomposition of a metal salt
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The invention discloses a catalyst for diesel vehicle tail gas, a preparation process and application thereof. The preparation process comprises the following steps: (1) Mixing the oxide slurry with a tungstate to form a first slurry; adding a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt to the first slurry to form a second slurry; (2) Mixing the second slurry, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt to obtain a third slurry; (3) Mixing the third slurry with a binder to obtain a fourth slurry; loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain a catalyst; wherein the oxide slurry contains alumina and at least one oxide selected from cerium oxide and zirconium oxide. The catalyst obtained by the method has lower ignition temperature after being subjected to high-temperature treatment.

Description

Catalyst for diesel vehicle tail gas and preparation process and application thereof
Technical Field
The invention relates to a catalyst for diesel vehicle tail gas, a preparation process and application thereof.
Background
Diesel exhaust contains a large amount of carbon monoxide, nitrogen oxides and hydrocarbons, which are the main sources of atmospheric pollution. Diesel Oxidation Catalysts (DOC) are key cores of diesel exhaust gas treatment systems, which can be applied to the oxidation of carbon monoxide and hydrocarbons. Up to now, diesel Oxidation Catalysts (DOC) on the market have the problems of large noble metal consumption and poor high temperature resistance and aging resistance. Therefore, the use level of noble metal is reduced, and the improvement of the high temperature and aging resistance of the catalyst is of great significance.
CN1935370a discloses a preparation method of a three-way catalyst for purifying automobile exhaust by using liquefied petroleum gas as fuel. The method comprises the following steps: (1) Immersing the cordierite honeycomb ceramic carrier in the coating water slurry, drying, roasting, and coating the coating on the cordierite honeycomb ceramic; the coating water slurry is cerium-zirconium solid solution, rare earth oxide, aluminum oxide, tackifier and water. (2) The cordierite honeycomb ceramic carrier containing the coating is immersed in aqueous solution containing palladium salt, rhodium salt, nickel salt and cerium salt by adopting an isovolumetric immersion method, dried and roasted, and then reduced by hydrogen to prepare the catalyst. The catalyst is not suitable for purifying tail gas of diesel vehicles, and has poor high temperature resistance and aging resistance, and the light-off temperature is increased after high temperature treatment.
CN107649126a discloses a double-base noble metal DOC catalyst for purifying diesel exhaustIs prepared by the preparation method of (1). The method comprises the following steps: (1) Mixing alumina powder or/and modified alumina powder, cerium-zirconium oxide or/and modified cerium-zirconium oxide according to a certain proportion, preparing the mixed powder into slurry, and putting the slurry into a ball mill or a sand mill for grinding; (2) The noble metal pt salt solution and the pd salt solution are treated with HAC or NH 3 ·H 2 O adjusting the pH value of the slurry, diluting the noble metal salt solution by deionized water respectively, fully stirring the noble metal salt solution, slowly dropwise adding the noble metal pt salt solution into the pd salt solution, and keeping the pd salt solution in a stirring state all the time; fully stirring the two noble metal salt solutions after the dripping is finished; (3) Slowly dripping the solution containing two noble metal salts into the slurry prepared in the step (1) with a certain mass, wherein the slurry is always in a stirring state; and (3) aging to obtain the pt-pd slurry containing the double-base noble metal, namely the DOC catalyst containing the double-base noble metal. The catalyst obtained by the method has poor high temperature resistance and aging resistance, and the light-off temperature is increased after high temperature treatment.
Disclosure of Invention
In view of the above, in one aspect, the present invention provides a process for preparing a catalyst for diesel exhaust, where the catalyst obtained by the process has a lower light-off temperature after being subjected to high temperature treatment. In another aspect, the invention provides a catalyst for diesel vehicle exhaust. In yet another aspect, the invention provides the use of a composition.
In one aspect, the invention provides a preparation process of a catalyst for diesel vehicle exhaust, which comprises the following steps:
(1) Mixing the oxide slurry with a tungstate to form a first slurry; adding a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt to the first slurry to form a second slurry;
(2) Mixing the second slurry, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt to obtain a third slurry;
(3) Mixing the third slurry with a binder to obtain a fourth slurry; loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain a catalyst;
wherein the oxide slurry contains alumina and at least one oxide selected from cerium oxide and zirconium oxide.
According to the preparation process of the invention, preferably, the amount of the tungstate is 0.5 to 5wt% of the total mass of the oxide in the oxidant slurry, based on the tungsten trioxide; the tungstate is selected from one or more of ammonium tungstate, ammonium meta-tungstate or ammonium paratungstate.
According to the production process of the present invention, preferably, the oxide slurry contains alumina, zirconia and ceria, and the mass ratio of the ceria, zirconia and alumina is (0.01 to 0.07): 0.04 to 0.09): 1, and the mass ratio of the ceria and zirconia is (1 to 4): 2 to 5.
According to the preparation process of the present invention, preferably, a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt is added to the first slurry to form a second slurry;
based on the substrate of the cordierite honeycomb ceramic carrier, the loading amount of platinum element is 8-25 g/ft 3 The load of palladium element is 3-12 g/ft 3 The method comprises the steps of carrying out a first treatment on the surface of the The mass ratio of the platinum element to the palladium element is (1-4): 1; wherein the platinum element is calculated by a platinum simple substance, and the palladium element is calculated by a palladium simple substance.
According to the preparation process of the invention, preferably, the lanthanum element is used in an amount of 0.5 to 5wt% based on the total mass of the oxides in the oxidant slurry; the amount of yttrium element is 0.5 to 5 weight percent of the total mass of the oxide in the oxidant slurry based on yttrium oxide.
According to the preparation process of the present invention, preferably, the water-soluble zirconium salt is used in an amount of 1 to 7wt% based on the total mass of the oxides in the oxidizer slurry, based on the zirconia.
According to the preparation process of the present invention, preferably, the binder is one or more selected from the group consisting of alumina sol, pseudo-boehmite, silica sol, cellulose, citric acid, polyvinyl alcohol, and polyethylene glycol;
the drying temperature is 90-130 ℃ and the drying time is 2-6 h; roasting temperature is 500-800 ℃ and roasting time is 2-6 h;
the total loading of each element in the fourth slurry on the cordierite honeycomb ceramic carrier is 150-180 g/L, calculated as oxide.
The invention also provides a preparation process of the catalyst, which comprises the following steps:
(1) Mixing the oxide slurry with a tungstate to form a first slurry; adding a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt to the first slurry to form a second slurry;
(2) Mixing the second slurry, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt to obtain a third slurry;
(3) Mixing the third slurry with a binder to obtain a fourth slurry; loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain a roasting product;
(4) Treating the roasting product at 700-1000 ℃ for 1-8 h to obtain a catalyst;
wherein the oxide slurry contains alumina and at least one oxide selected from cerium oxide and zirconium oxide.
On the other hand, the invention provides a catalyst for diesel vehicle exhaust, which is obtained by the preparation process;
the corresponding temperatures of the fresh catalyst, the aged catalyst and the catalyst after high-temperature treatment for the CO conversion rate of 50 percent are 140-180 ℃, 140-180 ℃ and 140-180 ℃ respectively;
fresh catalyst, aged catalyst and catalyst pair C after high temperature treatment 3 H 6 The corresponding temperatures are 180-195 ℃, 170-195 ℃ and 170-195 ℃ when the conversion rate is 50%;
the test was carried out in a fixed bed reactor under the following reaction conditions: co=200 ppm, C 3 H 6 ＝180ppm、NO＝500ppm、CO 2 ＝10vol％、O 2 ＝10vol％，H 2 O＝7vol％、N 2 To balance the gas, the total flow is 550ml/min and the airspeed is 80000h -1 The method comprises the steps of carrying out a first treatment on the surface of the The reaction temperature interval is 100-500 ℃; the aging conditions are as follows: h 2 O=10vol%, space velocity 60000h -1 The aging temperature is 650 ℃ and the aging time is 100 hours; the high temperature treatment conditions are as follows: roasting at 800 deg.c for 3 hr.
In yet another aspect, the present invention provides a use of a composition comprising a tungstate, a water-soluble lanthanum salt, a water-soluble yttrium salt, and a water-soluble zirconium salt for reducing the light-off temperature of a catalyst for diesel exhaust after high temperature treatment; the high temperature treatment conditions are as follows: high-temperature treatment is carried out for 1-8 h at 700-1000 ℃.
The catalyst for diesel vehicle tail gas prepared by the method has lower ignition temperature, and the ignition temperature of the catalyst can be further reduced after hydrothermal aging or high-temperature treatment. The applicant has unexpectedly found that the addition of water-soluble lanthanum salts, water-soluble yttrium salts, tungstates and water-soluble zirconium salts during the preparation of the catalyst gives catalysts having lower light-off temperatures after high temperature treatment.
Detailed Description
The present invention will be further described with reference to specific examples, but the scope of the present invention is not limited thereto.
< method for producing catalyst >
The preparation method of the catalyst comprises the following steps: (1) a step of preparing a slurry of the supported catalytically active element; (2) a step of preparing a supporting slurry containing an auxiliary agent; (3) a step of preparing a catalyst. In addition, the invention can also comprise the following steps: (4) a step of high-temperature treatment. The catalyst of the invention is suitable for treating tail gas of diesel vehicles.
Step of preparing a slurry carrying catalytically active elements
Mixing the oxide slurry with a tungstate to form a first slurry; a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt is added to the first slurry to form a second slurry. According to one embodiment of the invention, an oxide slurry is mixed with a tungstate to form a first slurry; a solution containing a water-soluble palladium salt is added to the first slurry to form a second slurry. According to another embodiment of the invention, an oxide slurry is mixed with a tungstate to form a first slurry; a solution containing a water-soluble platinum salt is added to the first slurry to form a second slurry. According to yet another embodiment of the invention, an oxide slurry is mixed with a tungstate to form a first slurry; a solution containing a water-soluble palladium salt and a water-soluble platinum salt is added to the first slurry to form a second slurry.
The oxide slurry is formed from an oxide and water. The oxide contains alumina and at least one oxide selected from cerium oxide and zirconium oxide. In certain embodiments, the oxides comprise alumina, ceria, and zirconia. The oxide may be composed of alumina, ceria, and zirconia. According to a preferred embodiment of the present invention, the oxide may consist of a solid solution of alumina and cerium zirconium. The mass ratio of cerium oxide to aluminum oxide may be (0.01 to 0.07): 1; preferably (0.02-0.06): 1; more preferably (0.03-0.05): 1. The mass ratio of zirconia to alumina may be (0.04 to 0.09): 1; preferably (0.05 to 0.09): 1; more preferably (0.06-0.08): 1. The mass ratio of cerium oxide to zirconium oxide can be (1-4): 2-5; preferably (1-3) is (2-4); more preferably (2-3) to (3-4). Thus being beneficial to reducing the ignition temperature of the catalyst and improving the ageing resistance and high temperature resistance of the catalyst.
The solids content of the oxide slurry may be 25 to 45wt%; preferably 30 to 40wt%; more preferably 33 to 37wt%. The average value of the particle size of the solid particles in the oxide slurry may be 1 to 10 μm; preferably 3 to 8 μm; more preferably 4 to 7. Mu.m.
The tungstate may be one or more selected from ammonium tungstate, ammonium meta-tungstate, and ammonium paratungstate. Preferably, the tungstate is ammonium metatungstate. The dosage of the tungstate is 0.5 to 5 weight percent of the total mass of the oxide in the oxidant slurry based on the tungsten trioxide; preferably 1 to 4 wt.%; more preferably 1 to 3wt%.
The mass fraction of solute in the solution containing the water-soluble palladium salt and/or the water-soluble platinum salt may be 10 to 25wt%; preferably 15 to 25 wt.%; more preferably 15 to 20wt%. The water-soluble palladium salt and/or the water-soluble platinum salt may be a nitrate salt, such as palladium nitrate, platinum nitrate. Taking a substrate of the cordierite honeycomb ceramic carrier as a reference, and taking a platinum simple substance as a reference, wherein the loading amount of platinum element is 8-25 g/ft 3 The method comprises the steps of carrying out a first treatment on the surface of the Preferably 8 to 20g/ft 3 The method comprises the steps of carrying out a first treatment on the surface of the More preferably 13 to 18g/ft 3 . Carried by cordierite honeycomb ceramicsThe matrix of the body is used as a reference, and the load of palladium element is 3-12 g/ft based on the palladium simple substance 3 The method comprises the steps of carrying out a first treatment on the surface of the Preferably 5 to 10g/ft 3 The method comprises the steps of carrying out a first treatment on the surface of the More preferably 7 to 10g/ft 3 . The mass ratio of the platinum element to the palladium element may be (1-4): 1; preferably (1-3): 1; more preferably (2-3): 1. Thus being beneficial to reducing the ignition temperature of the catalyst and improving the ageing resistance and high temperature resistance of the catalyst.
Step of preparing a supporting slurry containing an auxiliary agent
And mixing the second slurry, the water-soluble lanthanum salt, the water-soluble yttrium salt and the water-soluble zirconium salt to obtain a third slurry.
The dosage of lanthanum element is 0.5-5 wt% of the total mass of oxide in the oxidant slurry based on lanthanum oxide; preferably 1 to 4 wt.%; more preferably 1 to 3wt%. The amount of yttrium element is 0.5 to 5 weight percent of the total mass of oxide in the oxidant slurry based on yttrium oxide; preferably 1 to 4 wt.%; more preferably 1 to 3wt%. The lanthanum element is calculated by lanthanum oxide, the yttrium element is calculated by yttrium oxide, and the mass ratio of the lanthanum element to the yttrium element can be 1 (0.5-2); preferably 1 (0.5-1.5); more preferably 1 (1) to 1.5). Thus being beneficial to reducing the ignition temperature of the catalyst and improving the ageing resistance and high temperature resistance of the catalyst.
The water-soluble lanthanum salt and the water-soluble yttrium salt can be nitrate, sulfate, acetate or chloride. Examples of water-soluble lanthanum salts, water-soluble yttrium salts include, but are not limited to: lanthanum chloride, yttrium chloride, lanthanum nitrate, yttrium nitrate, lanthanum oxide, and yttrium oxide.
The water-soluble zirconium salt can be selected from one or more of zirconium acetate, zirconium nitrate and zirconium chloride; zirconium acetate is preferred. The dosage of the water-soluble zirconium salt is 1 to 7 weight percent of the total mass of the oxide in the oxidant slurry based on the zirconium oxide; preferably 2 to 6 wt.%; more preferably 2 to 4wt%. The mass fraction of the solute in the water-soluble zirconium salt can be 15-30wt%; preferably 17 to 25 wt.%; more preferably 20 to 25wt%. Thus being beneficial to reducing the ignition temperature of the catalyst and improving the ageing resistance and high temperature resistance of the catalyst.
Step of preparing catalyst
Mixing the third slurry with a binder to obtain a fourth slurry; and loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain the catalyst.
The binder may be one or more selected from aluminum sol, pseudo-boehmite, silica sol, cellulose, citric acid, polyvinyl alcohol, polyethylene glycol. Preferably, the binder is selected from one or more of an alumina sol, pseudo-boehmite, silica sol. More preferably, the binder is an aluminum sol. The amount of the binder is 45-75wt% of the mass of the oxide in the oxide slurry; preferably 50 to 70 wt.%; more preferably 55 to 65wt%.
The drying temperature can be 90-130 ℃; preferably 100 to 130 ℃; more preferably 100 to 120 ℃. The drying time can be 2-6 hours; preferably 2 to 5 hours; more preferably 2 to 4 hours.
The roasting temperature can be 500-750 ℃; preferably 500 to 700 ℃; more preferably 500 to 600 ℃. The roasting time can be 2-6 hours, preferably 2-5 hours; more preferably 2 to 4 hours.
The total load of each element in the fourth slurry on the cordierite honeycomb ceramic carrier is 150-180 g/L calculated by oxide; preferably 150 to 170g/L; more preferably 155 to 165g/L.
High temperature treatment step
The preparation process of the catalyst of the invention can comprise the following steps:
(1) Mixing the oxide slurry with a tungstate to form a first slurry; adding a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt to the first slurry to form a second slurry;
(2) Mixing the second slurry, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt to obtain a third slurry;
(3) Mixing the third slurry with a binder to obtain a fourth slurry; loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain a roasting product;
(4) And (3) treating the roasting product at a high temperature of 700-1000 ℃ for 1-8 h to obtain the catalyst.
Wherein the oxide slurry contains alumina and at least one oxide selected from cerium oxide and zirconium oxide.
Steps (1) to (4) are as described above. In step (5), the temperature of the high temperature treatment may be 700 to 1000 ℃, preferably 800 to 950 ℃, more preferably 800 to 900 ℃. The time of the high temperature treatment may be 1 to 8 hours, preferably 1 to 6 hours, more preferably 2 to 5 hours. This is advantageous in reducing the light-off temperature of the catalyst.
< catalyst >
The catalyst of the invention is prepared by the process. The corresponding temperature of the fresh catalyst for CO conversion is 140-180 ℃ when the CO conversion is 50%; preferably 150-180 ℃; more preferably 160 to 170 ℃. The temperature corresponding to the aged catalyst when the CO conversion rate is 50% is 140-180 ℃; preferably 160-175 ℃; more preferably 160 to 165 ℃. The corresponding temperature of the catalyst after high temperature treatment is 140-180 ℃ when the CO conversion rate is 50%; preferably 150 to 175 ℃; more preferably 155 to 165 ℃. Fresh catalyst pair C 3 H 6 The corresponding temperature is 180-195 ℃ when the conversion rate is 50%; preferably 185-195 ℃; more preferably 185 to 190 ℃. Catalyst pair C in aged state 3 H 6 The corresponding temperature is 170-195 ℃ when the conversion rate is 50%; preferably 180-190 ℃; more preferably 180 to 185 ℃. Catalyst pair C after high temperature treatment 3 H 6 The corresponding temperature is 170-195 ℃ when the conversion rate is 50%; preferably 180-190 ℃; more preferably 180 to 185 ℃.
The test conditions were as follows:
the test was carried out in a fixed bed reactor under the following reaction conditions: co=200 ppm, C 3 H 6 ＝180ppm、NO＝500ppm、CO 2 ＝10vol％、O 2 ＝10vol％，H 2 O＝7vol％、N 2 To balance the gas, the total flow is 550ml/min and the airspeed is 80000h -1 The method comprises the steps of carrying out a first treatment on the surface of the The reaction temperature interval is 100-500 ℃.
Aging conditions: h 2 O=10vol%, space velocity 60000h -1 The aging temperature is 650 ℃, and the aging time is 100 hours;
high temperature treatment conditions: roasting at 800 deg.c for 3 hr.
< use of composition >
The invention also provides the application of the composition in reducing the light-off temperature of the catalyst after high-temperature treatment. The composition comprises tungstate, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt. In certain embodiments, the composition consists of a tungstate salt, a water-soluble lanthanum salt, a water-soluble yttrium salt, and a water-soluble zirconium salt.
The high temperature treatment condition is that the high temperature treatment is carried out for 1 to 8 hours at the temperature of 700 to 1000 ℃. Preferably at a high temperature of 800 to 950 ℃ for 1 to 6 hours. More preferably at 800 to 900 ℃ for 2 to 5 hours.
The tungstate may be one or more selected from ammonium tungstate, ammonium meta-tungstate, and ammonium paratungstate. Preferably, the tungstate is ammonium metatungstate. The dosage of the tungstate is 0.5 to 5 weight percent of the total mass of the oxide in the oxidant slurry based on the tungsten trioxide; preferably 1 to 4 wt.%; more preferably 1 to 3wt%.
The dosage of lanthanum element is 0.5-5 wt% of the total mass of oxide in the oxidant slurry based on lanthanum oxide; preferably 1 to 4 wt.%; more preferably 1 to 3wt%. The amount of yttrium element is 0.5 to 5 weight percent of the total mass of oxide in the oxidant slurry based on yttrium oxide; preferably 1 to 4 wt.%; more preferably 1 to 3wt%. The lanthanum element is calculated by lanthanum oxide, the yttrium element is calculated by yttrium oxide, and the mass ratio of the lanthanum element to the yttrium element can be 1 (0.5-2); preferably 1 (0.5-1.5); more preferably 1 (1) to 1.5). Thus being beneficial to reducing the ignition temperature of the catalyst and improving the ageing resistance and high temperature resistance of the catalyst.
The water-soluble lanthanum salt and the water-soluble yttrium salt can be nitrate, sulfate, acetate or chloride. Examples of water-soluble lanthanum salts, water-soluble yttrium salts include, but are not limited to: lanthanum chloride, yttrium chloride, lanthanum nitrate, yttrium nitrate, lanthanum oxide, and yttrium oxide.
The water-soluble zirconium salt can be selected from one or more of zirconium acetate, zirconium nitrate and zirconium chloride; zirconium acetate is preferred. The dosage of the water-soluble zirconium salt is 1 to 7 weight percent of the total mass of the oxide in the oxidant slurry based on the zirconium oxide; preferably 2 to 6 wt.%; more preferably 2 to 4wt%. The mass fraction of the solute in the water-soluble zirconium salt can be 15-30wt%; preferably 17 to 25 wt.%; more preferably 20 to 25wt%. Thus being beneficial to reducing the ignition temperature of the catalyst and improving the ageing resistance and high temperature resistance of the catalyst.
In certain embodiments, the method specifically comprises the following steps:
(1) Mixing the oxide slurry with a tungstate to form a first slurry; adding a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt to the first slurry to form a second slurry;
(2) Mixing the second slurry, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt to obtain a third slurry;
(3) Mixing the third slurry with a binder to obtain a fourth slurry; and loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain the catalyst.
In certain embodiments, the method specifically comprises the following steps:
(1) Mixing the oxide slurry with a tungstate to form a first slurry; adding a solution containing a water-soluble palladium salt and/or a water-soluble platinum salt to the first slurry to form a second slurry;
(2) Mixing the second slurry, water-soluble lanthanum salt, water-soluble yttrium salt and water-soluble zirconium salt to obtain a third slurry;
(3) Mixing the third slurry with a binder to obtain a fourth slurry; loading the fourth slurry on a cordierite honeycomb ceramic carrier, and then drying and roasting to obtain a roasting product;
(4) And (3) treating the roasting product at a high temperature of 700-1000 ℃ for 1-8 h to obtain the catalyst.
The parameters of the steps and the parameters of the raw materials are as described above.
The following raw materials are introduced:
the content of zirconium in the cerium-zirconium solid solution was 60wt% (calculated as zirconium oxide), and the content of cerium was 40wt% (calculated as cerium oxide).
The mass fraction of palladium element in the palladium nitrate solution is 17.4wt%.
The mass fraction of platinum element in the platinum nitrate solution was 17.7wt%.
The mass fraction of zirconium acetate in the zirconium acetate solution was 22wt%.
Example 1
766g of alumina, 87g of cerium-zirconium solid solution and water were uniformly mixed to form a mixed slurry (solid content: 35 wt%); the mixed slurry was ball-milled until the average particle size of the solid particles in the mixed slurry was 5 μm, to obtain an oxide slurry. 23g of ammonium metatungstate was added to the oxide slurry to form a first slurry. 13g of a palladium nitrate solution and 25.6g of a platinum nitrate solution were added dropwise to the first slurry in a stirred state, respectively, to obtain a second slurry.
To the second slurry, 53g of lanthanum nitrate, 68g of yttrium nitrate and 318g of zirconium acetate solution were added to obtain a third slurry.
500g of an alumina sol was added to the third slurry to obtain a fourth slurry. Immersing the cordierite honeycomb ceramic carrier into the fourth slurry, taking out, and purging the excess slurry; drying at 110deg.C for 3 hr, and calcining at 550deg.C for 3 hr to obtain catalyst (calculated as oxide, catalyst loading of 160g/L; total load of palladium element and platinum element of 25 g/ft) 3 The palladium element is calculated as palladium simple substance, and the platinum element is calculated as platinum simple substance).
Example 2
766g of alumina, 87g of cerium-zirconium solid solution and water were uniformly mixed to form a mixed slurry (solid content: 35 wt%); the mixed slurry was ball-milled until the average particle size of the solid particles in the mixed slurry was 5 μm, to obtain an oxide slurry. 23g of ammonium metatungstate was added to the oxide slurry to form a first slurry. 13g of a palladium nitrate solution and 25.6g of a platinum nitrate solution were added dropwise to the first slurry in a stirred state, respectively, to obtain a second slurry.
To the second slurry, 53g of lanthanum nitrate, 68g of yttrium nitrate and 318g of zirconium acetate solution were added to obtain a third slurry.
500g of an alumina sol was added to the third slurry to obtain a fourth slurry. Immersing the cordierite honeycomb ceramic carrier into the fourth slurry, taking out, and purging the excess slurry; and then drying for 3 hours at 110 ℃, and roasting the dried cordierite honeycomb ceramic for 3 hours at 550 ℃ to obtain a roasting product.
And (3) placing the roasting product in a muffle furnace, and roasting for 3 hours at 800 ℃ to obtain the catalyst. T of the catalyst 50 (CO) 160 ℃; t (T) 50 (C 3 H 6 ) Is 181 ℃.
Comparative example 1
Uniformly mixing 894g of aluminum oxide, 99g of cerium-zirconium solid solution and water to form mixed slurry (the solid content is 35 wt%); the mixed slurry was ball-milled until the average particle size of the solid particles in the mixed slurry was 5 μm, to obtain an oxide slurry. 13g of a palladium nitrate solution and 25.6g of a platinum nitrate solution were added dropwise to the oxide slurry in a stirred state, respectively, to obtain a first slurry.
500g of an alumina sol was added to the first slurry to obtain a second slurry. Immersing the cordierite honeycomb ceramic carrier into the second slurry, taking out, and purging the excess slurry; drying at 110deg.C for 3 hr, and calcining at 550deg.C for 3 hr to obtain catalyst (calculated as oxide, catalyst loading of 160g/L; total load of palladium element and platinum element of 25 g/ft) 3 The palladium element is calculated as palladium simple substance, and the platinum element is calculated as platinum simple substance).
Comparative example 2
809g of alumina, 94g of cerium-zirconium solid solution and water were uniformly mixed to form a mixed slurry (solid content: 35 wt%); the mixed slurry was ball-milled until the average particle size of the solid particles in the mixed slurry was 5 μm, to obtain an oxide slurry. 13g of a palladium nitrate solution and 25.6g of a platinum nitrate solution were added dropwise to the oxide slurry in a stirred state, respectively, to obtain a first slurry.
To the first slurry, 53g of lanthanum nitrate and 68g of yttrium nitrate were added to obtain a second slurry.
500g of an alumina sol was added to the second slurry to obtain a third slurry. Immersing the cordierite honeycomb ceramic carrier into the third slurry, taking out, and purging the excess slurry; drying at 110deg.C for 3 hr, and calcining at 550deg.C for 3 hr to obtain catalyst (calculated as oxide, catalyst loading of 160g/L; total load of palladium element and platinum element of 25 g/ft) 3 The palladium element is calculated as palladium simple substance, and the platinum element is calculated as platinum simple substance).
Experimental example
The catalysts prepared in the above examples and comparative examples were tested for CO and C 3 H 6 The temperature corresponding to 50% conversion.
The test was carried out in a fixed bed reactor under the following reaction conditions: co=200 ppm, C 3 H 6 ＝180ppm、NO＝500ppm、CO 2 ＝10vol％、O 2 ＝10vol％，H 2 O＝7vol％、N 2 To balance the gas, the total flow is 550ml/min and the airspeed is 80000h -1 The method comprises the steps of carrying out a first treatment on the surface of the The reaction temperature interval is 100-500 ℃.
Aging conditions: h 2 O=10vol%, space velocity 60000h -1 The aging temperature is 650 ℃, and the aging time is 100h.
High temperature treatment conditions: the high temperature treatment is carried out in a muffle furnace and roasting is carried out at 800 ℃ for 3 hours. The test results are shown in Table 1.
TABLE 1
Figure BDA0002643964600000141
The present invention is not limited to the above-described embodiments, and any modifications, improvements, substitutions, and the like, which may occur to those skilled in the art, fall within the scope of the present invention without departing from the spirit of the invention.

Claims (1)

1. The preparation process of the catalyst for the tail gas of the diesel vehicle is characterized by comprising the following steps of:
766g of alumina, 87g of cerium-zirconium solid solution and water were uniformly mixed to form a mixed slurry with a solid content of 35 wt%; wherein, in the cerium-zirconium solid solution, the content of zirconium is 60wt percent calculated by zirconia; the content of cerium was 40wt% based on cerium oxide;
ball milling the mixed slurry until the average granularity of solid particles in the mixed slurry is 5 mu m, so as to obtain oxide slurry;
adding 23g of ammonium metatungstate to the oxide slurry to form a first slurry; respectively dropwise adding 13g of palladium nitrate solution and 25.6g of platinum nitrate solution into the first slurry in a stirring state to obtain second slurry; wherein the mass fraction of palladium element in the palladium nitrate solution is 17.4wt%, and the mass fraction of platinum element in the platinum nitrate solution is 17.7wt%;
adding 53g of lanthanum nitrate, 68g of yttrium nitrate and 318g of zirconium acetate solution to the second slurry to obtain a third slurry; wherein the mass fraction of the zirconium acetate solution is 22wt%;
adding 500g of aluminum sol into the third slurry to obtain fourth slurry;
immersing the cordierite honeycomb ceramic carrier into the fourth slurry, taking out, and purging the excess slurry; drying at 110 ℃ for 3 hours, and roasting the dried cordierite honeycomb ceramic at 550 ℃ for 3 hours to obtain a roasting product;
and (3) placing the roasting product in a muffle furnace, and roasting for 3 hours at 800 ℃ to obtain the catalyst.
CN202010848605.1A 2020-08-21 2020-08-21 Catalyst for diesel vehicle tail gas and preparation process and application thereof Active CN111974390B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010848605.1A CN111974390B (en) 2020-08-21 2020-08-21 Catalyst for diesel vehicle tail gas and preparation process and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010848605.1A CN111974390B (en) 2020-08-21 2020-08-21 Catalyst for diesel vehicle tail gas and preparation process and application thereof

Publications (2)

Publication Number Publication Date
CN111974390A CN111974390A (en) 2020-11-24
CN111974390B true CN111974390B (en) 2023-06-02

Family

ID=73443666

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010848605.1A Active CN111974390B (en) 2020-08-21 2020-08-21 Catalyst for diesel vehicle tail gas and preparation process and application thereof

Country Status (1)

Country Link
CN (1) CN111974390B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114849697B (en) * 2022-05-23 2023-10-27 东风汽车集团股份有限公司 Catalyst based on three-way catalyst ceramic carrier and preparation method thereof
CN117414821B (en) * 2023-12-08 2024-03-15 中自环保科技股份有限公司 High-temperature-resistant sintering Pt-based three-way catalyst and preparation method thereof

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110152721A (en) * 2019-06-25 2019-08-23 无锡威孚环保催化剂有限公司 The preparation method of wall-flow particulate trap catalyst

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000024518A (en) * 1998-07-10 2000-01-25 Tokyo Roki Co Ltd Production of catalyst device
CN101912775A (en) * 2010-09-03 2010-12-15 中国汽车技术研究中心 Selective catalyst for removing oxynitrides from tail gases of diesel vehicles and preparation method thereof
CN102580733A (en) * 2011-12-15 2012-07-18 无锡威孚环保催化剂有限公司 Method for preparing Pd-only catalyst used for tail gas purification of universal minitype petrol engines
CN104941677B (en) * 2014-12-18 2019-05-31 华东理工大学 A kind of coating material of high stability and the preparation method of Vehicle Exhaust Gas Cleaning Catalysts
CN105251485A (en) * 2015-11-04 2016-01-20 浙江达峰汽车技术有限公司 Motor vehicle exhaust purification catalyst and production process thereof
CN105233820A (en) * 2015-11-04 2016-01-13 浙江达峰汽车技术有限公司 High-stability catalyst for purifying tail gas of gasoline car and preparation method thereof
CN109621952B (en) * 2019-02-11 2021-09-03 无锡威孚环保催化剂有限公司 Catalyst for gasoline engine tail gas particulate matter filter and preparation method thereof
CN111375403A (en) * 2020-03-26 2020-07-07 包头稀土研究院 Catalyst for treating motor vehicle tail gas and preparation method and application thereof

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110152721A (en) * 2019-06-25 2019-08-23 无锡威孚环保催化剂有限公司 The preparation method of wall-flow particulate trap catalyst

Also Published As

Publication number Publication date
CN111974390A (en) 2020-11-24

Similar Documents

Publication Publication Date Title
US6069111A (en) Catalysts for the purification of exhaust gas and method of manufacturing thereof
US3615166A (en) Catalysts for purification of waste gases containing oxides of nitrogen
CN111974390B (en) Catalyst for diesel vehicle tail gas and preparation process and application thereof
CN112076803B (en) Ammonia oxidation catalyst, preparation method and application
CN102909020B (en) Sulfur-resistant catalytic-combustion catalyst and preparation method thereof
CN113304745B (en) Pt-Pd-Rh ternary catalyst and preparation method thereof
US4996180A (en) Catalyst of copper oxide and ceria
JPS6291244A (en) Catalyst for purifying exhaust gas
CN109482226A (en) One-step method prepares transition metal modified molecular sieve integral type catalyst and method
JP7187654B2 (en) Exhaust gas purification catalyst composition and automobile exhaust gas purification catalyst
Papadakis et al. Development of high performance, Pd-based, three way catalysts
CN111957312B (en) Catalyst for motor vehicle tail gas and preparation method and application thereof
WO2022143265A1 (en) Noble metal single atom supported three-way catalyst and preparation method therefor and use thereof
CN116510747B (en) Three-way catalyst and preparation method thereof
WO2006095392A1 (en) Process for producing catalyst for discharge gas treatment
CN113019411B (en) Boron nitride supported platinum-based catalyst for low-temperature selective catalytic oxidation of ammonia, preparation method and application thereof
CN112246251B (en) Natural gas automobile exhaust purification catalyst and preparation method thereof
CN112316961B (en) Automobile exhaust treatment catalyst and preparation method thereof
JP3161113B2 (en) Exhaust gas purification catalyst
JP5030573B2 (en) Composite oxide powder and method for producing the same
JPH0398644A (en) Preparation of catalyst for purifying exhaust gas
CN114247450A (en) Catalytic composition, catalyst layer, catalytic device and gas treatment system
CN112808270A (en) High-durability Pt-based integral three-way catalyst for gasoline vehicles, and preparation method and application thereof
JP3156577B2 (en) Material for exhaust gas purification catalyst and method for producing the same
JPS6054730A (en) Catalyst for purifying exhaust gas

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant