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CN-121972192-A - Supported catalyst based on carrier modification and preparation method and application thereof

CN121972192ACN 121972192 ACN121972192 ACN 121972192ACN-121972192-A

Abstract

The invention discloses a carrier-modified supported catalyst and a preparation method and application thereof, and relates to the technical field of supported catalysts, wherein the supported catalyst comprises an inert ceramic material and catalyst powder coated on the inert ceramic material, the catalyst powder comprises a modified carrier and an active component loaded on the modified carrier, the modified carrier comprises a carrier material and a modifier, the carrier is one or more of pure alumina or an aluminum-based composite material, the modifier is a mixture formed by an M source and a P source, the modified carrier is prepared by carrying out surface modification on the carrier through the mixture formed by the M source and the P source, the carrier is an M 3 (PO 4 ) δ carrier or an M 3 (PO 4 ) δ carrier, and the active component comprises noble metal particles dispersed in the modified carrier material. The catalyst can be directly applied to three-way catalysis of motor vehicles, and the catalyst prepared by the method disclosed by the invention takes the natural gas vehicle equivalent ratio combustion reaction as an application case, so that the light-off performance and the durability can be effectively improved.

Inventors

  • XIANG YI
  • LI DACHENG
  • WANG YUN
  • CHEN QIZHANG
  • DU HONGYI
  • XIAO YONGLI
  • He Lincong
  • Zhang Zizhan
  • LI YANG
  • ZHANG HAIYANG
  • XIE KAI
  • ZHOU ZHENGHONG

Assignees

  • 中自科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260227

Claims (11)

  1. 1. A supported catalyst based on modification of a support, characterized in that: The catalyst powder comprises an inert ceramic material and catalyst powder coated on the inert ceramic material, wherein the catalyst powder comprises a modified carrier and an active component loaded on the modified carrier; The modified carrier comprises a carrier material and a modifier, wherein the carrier material is one or more of pure alumina or an aluminum-based composite material, and the modifier is a mixture formed by an M source and a P source; The M source comprises any one or more combinations of alkali metal, alkaline earth metal, transition metal or rare earth metal, and the P source comprises any one or more combinations of phosphorus oxide, orthophosphoric acid, phosphorous acid, hypophosphorous acid, hypophosphite and halide; The active component comprises a noble metal composition dispersed on the surface of a modified support material.
  2. 2. The supported catalyst of claim 1, wherein the molar ratio of M δ+ to PO 4 3- in the mixture of M source and P source is 1 (0.36-1.5) such that M δ+ forms M 3 (PO 4 ) δ substantially.
  3. 3. The supported catalyst based on carrier modification according to claim 1, wherein the mass percentage of M 3 (PO 4 ) δ on the modified carrier is 0.1-30 wt% of the total carrier.
  4. 4. The supported catalyst based on the modification of the carrier according to claim 1, wherein the carrier material is Al 2 O 3 , and the Al 2 O 3 content is 40% or more of the total amount of the carrier material; or the carrier material is an aluminum-based composite material and comprises Al2O3 and is formed by the Al2O3 and one or more components selected from rare earth oxide, alkaline earth oxide, silicon oxide, titanium oxide and zirconium oxide.
  5. 5. The supported catalyst according to claim 1, wherein the noble metal composition is based on Pd and contains Pt and/or Rh, and wherein the noble metal source in the noble metal composition comprises any one or more of Pt/Pd/Rh oxide, chloride, nitrate, acetate, and acetylacetonate.
  6. 6. The supported catalyst based on carrier modification according to claim 1, wherein the loading of noble metal in the supported catalyst is 15g/ft 3 ~80g/ft 3 , and taking 50g/ft 3 as an example, the ratio of Pt/Pd/Rh is (0-15): (25:50): (0-10).
  7. 7. A method for preparing the supported catalyst based on modification of a carrier according to any one of claims 1 to 6, comprising the steps of: (1) Under the acidic condition, the M source and the P source are jointly immersed on the carrier powder, and the carrier powder is dried and roasted after standing and ageing to obtain a modified carrier; (2) Adding the modified carrier into a noble metal impregnating solution for loading to obtain catalyst powder; (3) Mixing and ball milling the catalyst powder and the binder solution to obtain slurry, coating the slurry on a ceramic material, drying, roasting and aging to obtain the supported catalyst.
  8. 8. The method for preparing a supported catalyst based on modification of claim 7, wherein in step (1), the acidic condition is obtained by dispersing an acidic substance in water to form an acidic solution, and the acidic substance comprises any one or more of HCOOH, CH 3 COOH、HNO 3 、HCl、H 3 PO 4 , and H 2 SO 4 .
  9. 9. The method for preparing a supported catalyst based on modification of a carrier according to claim 7, wherein the calcination temperature is 500 ℃ to 900 ℃ when preparing the modified carrier and the supported catalyst.
  10. 10. The preparation method of the supported catalyst based on the modification of the carrier according to claim 7, wherein in the step (3), the loading amount of the slurry is 50-150 g/L.
  11. 11. The use of a supported catalyst based on a modification of a support according to any one of claims 1 to 6 or prepared by a preparation method according to any one of claims 7 to 10, characterized in that the supported catalyst is used for purifying exhaust gas from an internal combustion engine of a motor vehicle by equivalent ratio combustion.

Description

Supported catalyst based on carrier modification and preparation method and application thereof Technical Field The invention relates to the technical field of supported catalysts, in particular to a supported catalyst based on carrier modification and a preparation method and application thereof. Background Noble metal (Pt/Pd/Rh) catalysts have become the core of a variety of important catalytic systems due to their excellent redox properties. But the full representation of the catalytic conversion performance is highly dependent on the supported carrier material. The aluminum-based composite material mainly comprising Al 2O3 is an ideal carrier platform for loading noble metals by virtue of high specific surface area, controllable pore canal structure and proper interaction with active components, and is widely applied to some key environmental protection catalytic fields: 1) Stoichiometric three-way catalyst (TWC) In the purification reaction of the equivalent ratio combustion exhaust gas of the internal combustion engine of the motor vehicles such as gasoline vehicles, natural gas (CNG) and motorcycles, the catalyst needs to cooperatively and efficiently catalyze CO, HC and oxidation and reduction of NO x under the air-fuel ratio close to the stoichiometric ratio. The aluminum-based carrier, in particular to an aluminum-based composite material modified by rare earth (Ce, la and the like), not only provides a highly dispersed environment for noble metal nano particles, but also can effectively buffer fluctuation of an air-fuel ratio window by oxygen storage/release capability (OSC), thereby widening a triple effect window and meeting the current severe emission standards of national VI/European VI and the like. 2) Lean burn oxidation catalyst Under lean conditions, such as Diesel Oxidation Catalysts (DOC) and natural gas lean-burn engine oxidation catalysts (MOC). The aluminum-based carrier, especially gamma-Al 2O3 with a certain high thermal stability, has surface acid sites which are helpful for adsorption and activation of long-chain HC, and improves the overall purification efficiency. 3) Volatile Organic Compound (VOC) catalytic oxidation catalyst In the treatment of industrial waste gas, the noble metal/aluminum-based catalyst has high low-temperature activity and low ignition temperature, has oxidizing capability on various VOCs (such as benzene series, esters and aldehyde ketones), and can modulate the electronic state and the surface property of the carrier of the noble metal by designing a specific aluminum-based composite carrier aiming at different VOC components and complex working conditions, thereby enhancing the activity, the selectivity and the poisoning resistance of the catalyst. However, despite the wide spread use of noble metal/aluminum based catalysts, there are still challenges in sustaining: 1. The surface property of the traditional pure alumina or alkali/alkaline earth/rare earth metal modified alumina carrier mainly takes the effect of alumina as an inert support carrier, has single function and insufficient oxidation-reduction performance, and is difficult to construct an efficient multifunctional active site. 2. The doped metal in the carrier can not form a solid solution structure with strong interaction with alumina, and the surface of the carrier is easy to be hydroxylated and rapidly sintered and deactivated in a high-temperature vapor environment. 3. The lack of the redox sites that produce strong interactions with the noble metal results in insufficient light-off activity at low temperatures and poor high temperature durability of the catalyst. In addition, in recent years, the price of noble metals (Pt, pd, rh) has been increasing, and market demands have been decreasing. Therefore, the development of new carrier materials is becoming the core of cost reduction and synergy. In order to break through the limitations, researchers have developed various strategies to improve catalytic performance, with phosphorus/phosphate modification techniques being of great interest due to their high temperature stability, electronic structure regulation and surface acidity. For example, a mesoporous metal phosphate catalyst (CN 120205183A) with high crystallinity, large specific surface and good thermal stability is prepared by using phosphoric acid as a phosphorus source to modify inorganic metal salt, a Ni-based catalyst is prepared by using organic phosphine modified alumina, the metal-carrier interaction of a carrier AlPO x-Al2O3 and Ni is enhanced (CN 117816208A), and a phosphorus compound is adopted to modify the carrier to load active metal, so that the surface acidity of the carrier is optimized, and the thermal stability of the catalyst is further improved (CN 120695857A). However, existing phosphorus/phosphate modification techniques are contradictory and tend to sacrifice catalytic activity and support texture as stability is sought. Therefore, a strategy for synergistic