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CN-122006692-A - Anti-degradation automobile exhaust purification three-way catalyst and preparation method thereof

CN122006692ACN 122006692 ACN122006692 ACN 122006692ACN-122006692-A

Abstract

The anti-degradation three-way catalyst for purifying automobile tail gas comprises a carrier and a coating coated on the carrier, wherein the coating comprises a lower layer and an upper layer, the lower layer comprises lanthanum-aluminum composite oxide, a first cerium-zirconium composite oxide and a strontium-containing compound, and the upper layer comprises lanthanum-aluminum composite oxide, a second cerium-zirconium composite oxide and a strontium-containing compound; A preparation method of an anti-degradation three-way catalyst for purifying automobile exhaust comprises the steps of firstly, coating a lower coating, namely weighing lanthanum-aluminum composite oxide and first cerium-zirconium composite oxide, adding deionized water into a strontium compound to uniformly stir the lanthanum-aluminum composite oxide, the first cerium-zirconium composite oxide and the strontium compound to obtain first slurry, and secondly, coating an upper coating, namely weighing lanthanum-aluminum composite oxide and second cerium-zirconium composite oxide. According to the invention, the strontium-containing compound is introduced into the coating, so that the dispersity of noble metal in the catalyst is improved, the agglomeration and inactivation of high Wen Xiagui metal are delayed, and the phase change of lanthanum-aluminum oxide can be effectively inhibited, thereby improving the thermal stability of the catalyst.

Inventors

  • HU LIHUA
  • WANG XIANFU
  • WU XIAOMIN
  • Tan shan
  • SUN LINGCHAO
  • LIU YONGMEI
  • ZHANG FUMIN
  • WANG LONG
  • Qi Ruhui
  • MENG QINGHUA
  • Sun Qinlei
  • WANG HAIYAN
  • ZHAO KUN
  • LI MIN

Assignees

  • 山东艾泰克环保科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. The anti-degradation three-way catalyst for purifying automobile tail gas is characterized by comprising a carrier and a coating coated on the carrier, wherein the coating comprises a lower layer and an upper layer, the lower layer comprises lanthanum-aluminum composite oxide, a first cerium-zirconium composite oxide and a strontium-containing compound, and the upper layer comprises lanthanum-aluminum composite oxide, a second cerium-zirconium composite oxide and a strontium-containing compound.
  2. 2. The three-way catalyst for purifying automobile exhaust with resistance to deterioration according to claim 1, wherein the lower layer has a Pt content of 0-120 g/ft 3, a Pd content of 0-120 g/ft 3, and the upper layer has a Rh content of 0.1-20 g/ft 3.
  3. 3. The three-way catalyst for purifying automobile exhaust, as claimed in claim 1, wherein the lanthanum-aluminum composite oxide comprises 1 to 20wt% of lanthanum oxide and 80 to 99wt% of aluminum oxide in percentage by mass.
  4. 4. The three-way catalyst for purifying automobile exhaust, as claimed in claim 1, wherein the first cerium-zirconium composite oxide and the second cerium-zirconium composite oxide comprise 10wt% to 75wt% of ZrO2, 20wt% to 80wt% of CeO2 and 1wt% to 12wt% of transition metal oxide, and the transition metal oxide is one or more selected from La 2 O 3 、Y 2 O 3 、Pr 6 O 11 、Nd 2 O 3 .
  5. 5. The three-way catalyst for purifying automobile exhaust with resistance to deterioration as set forth in claim 1, wherein the strontium compound is one or more of strontium nitrate, strontium acetate, strontium chloride and strontium hydroxide.
  6. 6. The degradation-resistant three-way catalyst for automobile exhaust purification according to claim 1, wherein the lower layer comprises 20-80% by weight of lanthanum-aluminum composite oxide, 20-80% by weight of first cerium-zirconium composite oxide and 0.01-5% by weight of strontium compound.
  7. 7. The three-way catalyst for purifying automobile exhaust, as claimed in claim 1, wherein the upper layer comprises 20-80% by weight of lanthanum-aluminum composite oxide, 20-80% by weight of second cerium-zirconium composite oxide and 0.01-5% by weight of strontium compound.
  8. 8. The degradation-resistant automobile exhaust purification three-way catalyst according to claim 1, wherein the coating amount of the under-coating layer is 80-140 g/L.
  9. 9. The degradation-resistant automobile exhaust purification three-way catalyst according to claim 1, wherein the coating amount of the upper layer coating is 60-120 g/L.
  10. 10. A method for preparing a degradation-resistant three-way catalyst for purifying automobile exhaust gas, comprising the following steps of: Firstly, coating a lower coating, namely weighing lanthanum-aluminum composite oxide and first cerium-zirconium composite oxide according to a mass ratio of 2:8-8:2, wherein a strontium compound is 0.01% -5%, adding deionized water into the lanthanum-aluminum composite oxide, the first cerium-zirconium composite oxide and the strontium compound, stirring uniformly to obtain a first slurry, dripping at least one precursor solution of Pt and Pd into the first slurry, stirring uniformly to obtain lower coating slurry, coating the lower coating slurry on a carrier according to a mass ratio of 80-140 g/L, and finally drying and roasting to obtain a first semi-finished product; And step two, coating an upper coating, namely weighing lanthanum-aluminum composite oxide and second cerium-zirconium composite oxide according to a mass ratio of 2:8-8:2, wherein a strontium compound is 0.01% -5%, adding deionized water into the lanthanum-aluminum composite oxide, the second cerium-zirconium composite oxide and the strontium compound, uniformly stirring to obtain a first slurry, dropwise adding a precursor solution of Rh into the second slurry, uniformly stirring to obtain a lower coating slurry, coating the lower coating slurry on a carrier according to a mass ratio of 60-120 g/L, and finally drying and roasting to obtain a catalyst finished product.

Description

Anti-degradation automobile exhaust purification three-way catalyst and preparation method thereof Technical Field The invention relates to the technical field of automobile exhaust treatment, in particular to a degradation-resistant three-way catalyst for automobile exhaust purification and a preparation method thereof. Background With the rapid development of the automobile industry, the exhaust emission of the motor vehicle has become one of the important sources of atmospheric pollution, and the effective purification of pollutants such as carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NO x) in the exhaust is one of the key subjects in the current environmental protection field. The performance of the three-way catalyst as a core component for purifying automobile exhaust directly determines the exhaust treatment efficiency, however, in the actual use process, the existing three-way catalyst is in a high-temperature and complex working condition environment for a long time, so that the problems of deterioration such as noble metal agglomeration and carrier oxide phase change are easy to occur, the activity of the catalyst is reduced, the service life is shortened, and the increasingly strict exhaust emission standard is difficult to stably meet. To solve the problem, the stability of the catalyst is improved in the industry by optimizing coating components, improving preparation process and the like. For example, CN112221494A (Li Dacheng et al) discloses a method for preparing a catalyst by forming Pt-O bonds or Pt-O-Ce bonds by an impregnation method, which maintains the oxidation state of Pt to stabilize Pt, and additionally, pt, pd, alkaline earth metals and the like are co-impregnated with a modified alumina, and the addition of alkaline earth metals can improve the thermal stability of the catalyst. CN110404536a (Han Tianpeng et al) discloses a method for preparing a Pt/CeZr catalyst powder with high uniformity and purity, which improves the dispersibility of Pt, forms Pt-O bond and Pt-O-Ce bond, and improves the thermal stability of the catalyst. CN119633817a discloses a method for preparing a catalyst from Pd and MgO-Al 2O3, which can improve uniformity of Pd dispersion and ensure thermal stability of the catalyst. In addition, the La salt is impregnated in the outer layer of the catalyst, so that the sintering resistance of the catalyst is further improved. The patent provides a method for improving the dispersion uniformity of noble metal and enhancing the thermal stability of a catalyst by adding strontium element into the catalyst. Disclosure of Invention In order to solve the problems, the invention aims to provide a degradation-resistant three-way catalyst for purifying automobile exhaust and a preparation method thereof. In order to achieve the aim, the technical scheme of the invention is that the anti-degradation three-way catalyst for purifying the automobile tail gas comprises a carrier and a coating coated on the carrier, wherein the coating comprises a lower layer and an upper layer, the lower coating comprises lanthanum-aluminum composite oxide, a first cerium-zirconium composite oxide and a strontium-containing compound, and the upper layer comprises lanthanum-aluminum composite oxide, a second cerium-zirconium composite oxide and a strontium-containing compound. Further, the Pt content is 0-120 g/ft 3 in the lower layer, the Pd content is 0-120 g/ft 3, and the Rh content is 0.1-20 g/ft 3 in the upper layer. Further, the lanthanum-aluminum composite oxide comprises 1-20wt% of lanthanum oxide and 80-99wt% of aluminum oxide in percentage by mass. Further, the first cerium-zirconium composite oxide and the second cerium-zirconium composite oxide comprise 10-75wt% of ZrO2, 20-80wt% of CeO2 and 1-12wt% of transition metal oxide according to mass percentage, wherein the transition metal oxide is one or more selected from the group consisting of the following materials. Further, the strontium compound is one or more of strontium nitrate, strontium acetate, strontium chloride and strontium hydroxide. Further, the lower layer comprises 20-80 wt% of lanthanum-aluminum composite oxide, 20-80 wt% of first cerium-zirconium composite oxide and 0.01-5% of strontium compound according to mass percent. Further, the upper layer comprises 20-80 wt% of lanthanum-aluminum composite oxide, 20-80 wt% of second cerium-zirconium composite oxide and 0.01-5% of strontium compound in percentage by mass. Further, the coating amount of the lower coating is 80-140 g/L. Further, the coating amount of the upper layer coating is 60-120 g/L. The invention also provides a preparation method of the anti-degradation automobile exhaust purification three-way catalyst, which comprises the following steps: Firstly, coating a lower coating, namely weighing lanthanum-aluminum composite oxide and first cerium-zirconium composite oxide according to a mass ratio of 2:8-8:2, wherein a strontium compound is 0.01% -5%