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Preparation of thermally stable ALD modified specific crystal face CeO2 carrier loaded Pd three-way catalyst

A catalyst and nano-catalyst technology, applied in catalyst activation/preparation, physical/chemical process catalyst, metal/metal oxide/metal hydroxide catalyst, etc. Can not achieve accurate inhibition of noble metal sintering and other problems, to achieve good catalytic activity and high temperature resistance, noble metal dispersion, good catalytic activity and thermal stability.

Pending Publication Date: 2020-07-31
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this study cannot precisely control the cladding thickness, and the structure of the oxide-metal interface has different forces, so it cannot accurately suppress the sintering of noble metals.
Although the thermal stability of the three-way catalyst is improved to a certain extent, its catalytic activity is also very different
Emiel J.M.Hensen (Applied Catalysis B: Environmental 243 (2019) 36-46) found that CeO 2 The influence of exposing different facets on the catalytic activity of CO proves the difference in catalytic performance of different active facets, but the high temperature treatment easily leads to deformation of the facets, which affects its thermal stability

Method used

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  • Preparation of thermally stable ALD modified specific crystal face CeO2 carrier loaded Pd three-way catalyst
  • Preparation of thermally stable ALD modified specific crystal face CeO2 carrier loaded Pd three-way catalyst
  • Preparation of thermally stable ALD modified specific crystal face CeO2 carrier loaded Pd three-way catalyst

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] (1) Preparation of CeO by hydrothermal synthesis 2 Nano stave. The specific process is: at room temperature, mix 38.4g NaOH and 2.98g CeCl 3 ·7H 2 O was dissolved in 70ml and 10ml of deionized water respectively, and magnetically stirred for 0.5h at a speed of 800r / min to obtain NaOH solution (A) and CeCl 3 Solution (B), quickly add B to A, adjust the pH value to 12.5-12.8, CeCl 3 The concentration is 0.2mol / L, the speed is adjusted to 1000r / min, stirred for 1h, then put it into a polytetrafluoroethylene lining, and finally put it into a reaction kettle, and put it in an oven at 140°C for 24h. The samples were washed with deionized water and centrifuged until Cl-free -, and the filtrate was neutral, dried in an oven at 80°C for 12h, then placed in a muffle furnace, raised from room temperature to 500°C at a heating rate of 5°C / min and kept at this temperature for 4h, to obtain two Ceria nanorod support (CeO 2 -rod).

[0034] (2) Loading of ceria nanorod carrier: ...

Embodiment 2

[0036] Aging of 1# catalyst sample: Take a certain amount of 1# catalyst sample and place it in a muffle furnace, raise the temperature from room temperature to 1000°C at a rate of 5°C / min in an air atmosphere, and keep it warm for 5 hours. Recorded as 2# catalyst sample (a-Pd / CeO 2 -r).

Embodiment 3

[0038] (1) Unscrew the gas cylinder, turn on the computer, connect the device and open the control software, put 1g Pd / CeO 2 -r The catalyst is loaded into the reaction bottle of the sample compartment, the vacuum pump parameters are set, the hand valve of the vacuum pump is manually opened, and vacuum is carried out until the vacuum degree reaches a stable level. Set the temperature of the precursor TMA and the distilled water of the precursor, set the temperature of the reaction pipeline and the temperature of the reaction chamber, after the temperature reaches the set value, open the manual valve of the precursor, and use the control software to open the pneumatic valve to start the ALD cycle.

[0039] (2) Carry out 10cycles of Al on 1# catalyst sample 2 o 3 TLC touch up. The modified catalyst sample is recorded as 3# catalyst sample (10Al-Pd / CeO 2 -r).

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Abstract

The invention discloses preparation of a thermally stable ALD modified specific crystal face CeO2 carrier loaded Pd three-way catalyst, and belongs to the field of catalytic chemistry and nanoscience.The preparation method comprises the following steps: (1) weighing a certain amount of a cerium precursor and a sodium hydroxide precipitant into a beaker, dissolving, reacting, transferring a mixedsolution into a self-pressure reaction kettle, and carrying out hydrothermal reaction for 24 hours; and (2) washing, drying and grinding a reacted mixed solution into powder, putting the powder into amuffle furnace, and roasting for 4-6 hours at the temperature of 500-1000 DEG C to obtain cerium dioxide carriers with different morphologies; (3) mixing the prepared cerium dioxide carriers with a noble metal solution by an impregnation method to finally obtain a supported noble metal cerium-based catalyst; and (4) coating 5 to 20 cycles of Al2O3 through an atomic layer deposition (ALD) technology. The obtained catalyst has high catalytic activity and high-temperature thermal stability.

Description

technical field [0001] The present invention utilizes ALD technology to expose specific crystal face CeO 2 Carrier Supported Pd Catalyst Pd / CeO 2 Surface modification is carried out to improve its three-way catalytic performance. The invention relates to a preparation method of a Pd-based three-way catalyst with high performance, and belongs to the field of industrial catalysis. Background technique [0002] Exhaust gas from motor vehicles seriously endangers the environment and human health. People's awareness of environmental protection has gradually strengthened, and the government has also formulated increasingly strict vehicle exhaust emission standards. On December 23, 2016, the Ministry of Environmental Protection announced the National 6 emission standard, in which from July 1, 2020, all light vehicles sold and registered should comply with National 6b. Compared with the National V emission standards, the National VI emission standards have significantly lower po...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63B01J37/08B01J37/10B01J37/02B01D53/94B01D53/56B01D53/62B01D53/72C23C16/40C23C16/455
CPCB01J23/63B01J23/002B01J37/08B01J37/10B01J37/0201B01D53/945C23C16/45525C23C16/403B01J35/396B01J35/40Y02T10/12
Inventor 张桂臻李文胜何洪徐亚蒙何泽源
Owner BEIJING UNIV OF TECH