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A kind of ceria-based catalyst and its preparation method and application

A cerium oxide and catalyst technology, which is applied in the field of catalysts for the selective catalytic reduction of nitrogen oxides by ammonia, can solve the problems of decreased removal rate of nitrogen oxides, collapse of molecular sieve framework, lack of acidic sites, etc., to increase the interaction force , Increase the concentration of oxygen vacancies, promote the effect of adsorption and activation

Active Publication Date: 2021-03-30
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the biggest disadvantage of molecular sieve catalysts is that they are prone to dealumination under high-temperature hydrothermal conditions, resulting in the collapse of the molecular sieve framework and the loss of acidic sites, resulting in a rapid decline in the removal rate of nitrogen oxides.

Method used

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  • A kind of ceria-based catalyst and its preparation method and application
  • A kind of ceria-based catalyst and its preparation method and application
  • A kind of ceria-based catalyst and its preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Example 1: CeO 2 Preparation of / HAT heterostructure catalyst

[0037] Dissolve halloysite in ultrapure water, and use a rotary evaporator to draw a vacuum (vacuum degree of 0.05 MPa) until bubbles appear on the liquid surface, and it is kept under this condition for one hour. The above operation was repeated three times and then centrifuged, and dried at 80° C. for 12 hours to obtain halloysite after pretreatment. Weigh 0.5g halloysite and 1.74g Ce(NO 3 ) 3 ·6H 2 O was dispersed in 45 mL of ultrapure water and stirred for 1.5 hours. Then, 0.3 g of citric acid and 0.2 g of hexamethylenediamine were sequentially added to the above solution and stirred for 1 h respectively to obtain a precursor for hydrothermal reaction. The above precursors were transferred to a hydrothermal reactor and hydrothermally treated at 190 °C for 15 h. After the reaction, the solid product was collected by centrifugation. The product was washed 5 times with ultrapure water and dried in a...

Embodiment 2

[0039] Example 2: CeO 2 Preparation of / HAT heterostructure catalyst

[0040] Dissolve halloysite in ultrapure water, and use a rotary evaporator to draw a vacuum (vacuum degree of 0.07 MPa) until bubbles appear on the liquid surface, and it is kept under this condition for one hour. The above operation was repeated three times, then centrifuged, and dried at 95° C. for 10 h to obtain halloysite after pretreatment. Weigh 0.5g halloysite and 1.74g Ce(NO 3 ) 3 ·6H 2 O was dispersed in 45 mL of ultrapure water and stirred for 1 hour. Then, 0.3 g of citric acid and 0.2 g of hexamethylenediamine were sequentially added to the above solution and stirred for 1.5 h respectively to obtain a precursor for hydrothermal reaction. The above precursor was transferred to a hydrothermal reactor and hydrothermally treated at 180 °C for 20 h. After the reaction, the solid product was collected by centrifugation. The product was washed three times with ultrapure water and dried in an oven...

Embodiment 3

[0041] Example 3: CeO 2 Preparation of / HAT heterostructure catalyst

[0042] Dissolve halloysite in ultra-pure water, use a rotary evaporator to draw a vacuum (vacuum degree is 0.09MPa) until bubbles appear on the liquid surface, and keep under this condition for one hour. The above operation was repeated three times and then centrifuged, and dried at 110° C. for 8 hours to obtain halloysite after pretreatment. Weigh 0.5g halloysite and 1.74g Ce(NO 3 ) 3 ·6H 2 O was dispersed in 45 mL ultrapure water and stirred for 2 hours. Then, 0.3 g of citric acid and 0.2 g of hexamethylenediamine were sequentially added to the above solution and stirred for 1.5 h respectively to obtain a precursor for hydrothermal reaction. The above precursor was transferred to a hydrothermal reactor and hydrothermally treated at 200 °C for 10 h. After the reaction, the solid product was collected by centrifugation. The product was washed 6 times with ultrapure water and dried in an oven at 90 °C...

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Abstract

The invention discloses a cerium dioxide-based catalyst, which is mainly composed of Ce, Al, Si and O. The invention further discloses a preparation method of the cerium dioxide-based catalyst. The preparation method is simple in process and easy to operate and implement. The cerium dioxide-based catalyst disclosed by the invention can be applied to selective catalytic reduction of nitrogen oxideby ammonia gas, has excellent nitrogen oxide reduction capability and nitrogen selectivity, is wide in a reaction activity window, and has good sulfur dioxide poisoning resistance and hydrothermal stability. When the cerium dioxide-based heterostructure catalyst prepared by the method is used for treating nitrogen oxide in waste gas, the defects that a traditional vanadium-based catalyst has toxicaction on a human body and causes secondary pollution to the environment can be effectively overcome, and the cerium dioxide-based heterostructure catalyst has the advantages of economical efficiency, environmental friendliness and easiness in industrialization.

Description

technical field [0001] The invention relates to the field of catalysts for the selective catalytic reduction of nitrogen oxides by ammonia, in particular to a ceria-based heterostructure catalyst, a preparation method thereof and an application in the selective catalytic reduction of nitrogen oxides by ammonia. Background technique [0002] Diesel vehicles have been widely used at home and abroad because of their good economy, high fuel efficiency and high output power. However, diesel vehicles produce increasingly serious nitrogen oxides (NO x ) emissions, will cause a series of environmental problems such as acid rain, smog, photochemical smog, and an increase in the concentration of the near-ground ozone layer. my country's plan advocates the concept of green, clearly pointing out that by 2020, nitrogen oxide emissions will be reduced by 15% compared with 2015. In addition, the newly issued "Urban Vehicle Diesel Engine Exhaust Pollutant Emission Limits and Measurement M...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J23/10B01D53/94B01D53/56B01J35/02
CPCB01D53/56B01D53/9418B01D2251/2062B01D2257/40B01D2258/01B01J35/023Y02T10/12Y02A50/20
Inventor 李素静陈靓李伟王俏丽王晓祥马赫遥
Owner ZHEJIANG UNIV