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B-doped Cu-SSZ-13 molecular sieve as well as preparation method and application thereof

A cu-ssz-13 and molecular sieve technology, applied in the field of denitration catalysts, can solve the problems of weakened catalytic activity and low conversion rate

Active Publication Date: 2021-12-28
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

A large number of studies have shown that in the NH3-SCR reaction, the selectivity of Cu-SSZ-13 molecular sieve to N2 is close to 100% in a wide temperature range, however The conversion rate of NOx is still low at low temperature (200~550℃), and the catalytic activity is weakened after high temperature hydrothermal treatment

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  • B-doped Cu-SSZ-13 molecular sieve as well as preparation method and application thereof
  • B-doped Cu-SSZ-13 molecular sieve as well as preparation method and application thereof
  • B-doped Cu-SSZ-13 molecular sieve as well as preparation method and application thereof

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preparation example Construction

[0033] The invention provides a kind of preparation method of B-doped Cu-SSZ-13 molecular sieve, comprising the following steps:

[0034] Template agent, silicon source, aluminum source, alkali metal hydroxide, boron source and water are mixed to obtain initial sol; the consumption of described silicon source is SiO 2 In terms of moles, the amount of the aluminum source is Al 2 o 3 In terms of moles, the template agent, alkali metal hydroxide, Al 2 o 3 , SiO 2 The molar ratio with water is 0-0.2:0.2-0.7:0.2:1:15-80; B and SiO in the boron source 2 The molar ratio is less than 0.8;

[0035]performing a crystallization reaction on the initial sol, and performing a first roasting on the solid product obtained by the crystallization reaction to obtain a B-doped SSZ-13 molecular sieve;

[0036] mixing the B-doped SSZ-13 molecular sieve with a solution containing ammonium ions, performing ammonium ion exchange, and performing a second roasting on the molecular sieve obtained a...

Embodiment 1

[0065] According to template agent, KOH, Al 2 o 3 , SiO 2 1. The molar ratio of B and water in the boron source is 0.2:0.2:0.2:1:0.32:40. Dissolve 1g of Y (Si / Al=17) molecular sieve in 10mL of deionized water, then add 0.34g of KOH into the system and stir 5 minutes, continue to add 2.5g templating agent TMAdaOH (25%) and 0.41g Al(OH) to the solution 3 , and finally add 0.12gNaB to it 4 o 7, after stirring at room temperature for 2 h, the obtained sol was transferred to a polytetrafluoroethylene-lined stainless steel reactor and crystallized at 150 °C for 5 days. After the crystallization is completed, cool to room temperature, wash thoroughly with deionized water and dry, and then bake at 550°C for 6 hours to remove the template agent to obtain the original powder of B / Al-SSZ-13.

[0066] Take 2 g of B / Al-SSZ-13 raw powder and add it to 100 mL of deionized water, then add 8 g of ammonium nitrate, stir for 6 h in a water bath at 80 °C for ammonium ion exchange, and repeat...

Embodiment 2

[0069] The difference with embodiment 1 is only to add 0.29g NaB 4 o 7 , B and SiO in the boron source 2 The molar ratio is 0.8 to obtain Cu-B / Al-SSZ-13 molecular sieve.

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Abstract

The invention provides a B-doped Cu-SSZ-13 molecular sieve as well as a preparation method and application thereof, and belongs to the technical field of denitration catalysts. According to the invention, by introducing B atoms, different framework aluminum distributions are generated through induction, and the content of aluminum pairs in a double-six-membered ring is obviously increased, so that the content of active sites of bivalent copper ions connected to the aluminum pairs is increased in a copper ion loading process, and the catalytic activity of the catalyst is enhanced. Moreover, in the crystallization process of the molecular sieve, framework aluminum preferentially falls into an eight-membered ring on a CHA cage under the adjusting action of B, and compared with a double-six-membered ring, the eight-membered ring on the CHA cage is more open in space and is more beneficial to uniform distribution of Al atoms, so that distortion of an aluminum-oxygen tetrahedron is reduced under a hydrothermal condition, and the hydrothermal stability of the molecular sieve is greatly improved.

Description

technical field [0001] The invention relates to the technical field of denitrification catalysts, in particular to a B-doped Cu-SSZ-13 molecular sieve and its preparation method and application. Background technique [0002] NO x It is one of the main pollutants of automobile exhaust, which has brought great harm to the atmospheric environment and human health. Heavy-duty diesel vehicles, which account for 7.8% of the car population, emit 69% of NO x , this is because the diesel engine works at a higher air-fuel ratio. Under this lean combustion condition, although the combustion efficiency is the highest and the fuel consumption is low, it is accompanied by a large amount of NO x generation. In 2020, the National Sixth Automobile Exhaust Emission Standard will require diesel vehicle NO x Emissions put forward higher requirements, therefore, control and eliminate NO in diesel vehicle exhaust x become crucial. Diesel vehicle exhaust NO x The removal of carbon dioxide i...

Claims

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Application Information

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IPC IPC(8): B01J29/76B01D53/94B01D53/56
CPCB01J29/76B01D53/9413B01D2258/012Y02T10/12Y02A50/20
Inventor 焦卫勇樊卫斌吕文婷董梅白璞李延峰薛海霞
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI