Catalyst and preparation method and application thereof

A catalyst and template technology, applied in catalyst activation/preparation, molecular sieve catalysts, chemical instruments and methods, etc., can solve the problem of poor propylene selectivity and thermal stability, catalyst stability and catalytic efficiency need to be improved, metal atom sintering Reunion, etc.

Active Publication Date: 2019-11-22
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the catalyst exhibits excellent catalytic properties such as hydrogenation and dehydrogenation, the propylene selectivity and thermal stability are poor
Preparation of supported bimetallic catalysts by alloying design by compounding platinum with various metal elements (such as tin, gallium, copper, zinc, etc.) strategy, but the stability and catalytic efficiency of this type of catalyst still need to be improved
[0004] In addition, when people prepare metal-supported molecular sieve catalysts by in-situ synthesis methods, they all use the calcination-reduction process: that is, they are first calcined in air or oxygen to remove organic substances such as templates and ligands, and then reduced to zero in a hydrogen atmosphere. However, during the calcination-reduction process, metal atoms are easily sintered and agglomerated in the molecular sieve, and the size of the metal becomes larger

Method used

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  • Catalyst and preparation method and application thereof
  • Catalyst and preparation method and application thereof
  • Catalyst and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0152] The synthesis ratio of PtZnx@S-1-H(x=0~4) catalyst is SiO 2 :TPAOH:H 2 O:A([Pt(NH 2 CH 2 CH 2 NH 2 ) 2 ]Cl 2 ):B([Zn(NH 2 CH 2 CH 2 NH 2 ) 3 ](OAc) 2 )=1:0.4:35:A:B (A=2.25×10 -3 , A / B=1 / 1, 1 / 2, 1 / 3, 1 / 4, without adding B and without adding A), the specific synthesis steps are as follows:

[0153] 1) Mix 13g TPAOH solution with 15g deionized water, stir at 25°C for 1 hour to dilute;

[0154] 2) 0.024g PtCl 2 Add to 0.15ml of ethylenediamine and water mixed solution (volume ratio of ethylenediamine and water is 0.15:1), stir at 60°C for 1 hour to PtCl 2 After complete dissolution, [Pt(NH 2 CH 2 CH 2 NH 2 ) 2 ]Cl 2 solution; 0.02g, 0.039g, 0.059g, 0.078g of zinc acetate dihydrate (corresponding to Pt / Zn molar ratios of 1 / 1, 1 / 2, 1 / 3 and 1 / 4, respectively) were added to 0.3ml of ethylene dihydrate In the mixed solution of amine and water (the volume ratio of ethylenediamine and water is 0.3:1), after stirring at 25°C for 1 hour, [Zn(NH 2 CH 2 CH 2 ...

Embodiment 2

[0166] The propane dehydrogenation reaction of the catalyst is carried out under the reaction pressure of 0.1MPa in a quartz tube fixed-bed reactor with an inner diameter of 20 mm. Before the dehydrogenation reaction, mix 0.3g of catalyst (25-40 mesh) with 1g of quartz sand, under the condition of reaction temperature of 550°C, in 10ml / min of H 2 Flow down and reduce for 1h, then add propane volume fraction and be the propane / nitrogen mixed gas of 25% to react, the flow of mixed gas is 40ml / min (C 3 h 8 / N 2 =10 / 30ml min -1 ). Among them, the PtZnx@S-1-H catalyst is the catalyst prepared in Example 1.

[0167] The catalytic reaction of propane dehydrogenation in Fig. 4 demonstrates that, Figure 4A is the conversion rate of propane on various catalysts; Figure 4B propylene selectivity on various catalysts; Figure 4C It is the long-term stability test results of PDH conversion on PtZn4@S-1-H and Pt@S-1-H catalysts. It can be seen from the figure that Pt@S-1-H has a hi...

Embodiment 3

[0186] In addition, the proportion of PtZn4@S-1-H catalyst synthesized by other raw materials is SiO 2 :TPAOH:H 2 O:([Pt(NH 2 CH 2 CH 2 NH 2 ) 2 ] 2+ ):([Zn(NH 2 CH 2 CH 2 NH 2 ) 3 ](NO 3 ) 2 )=1:0.25:30:4.5×10 -3 :1.8×10 -2 , the specific synthesis steps are as follows:

[0187] 1) Mix 8.1g of TPAOH solution with 13g of deionized water, and stir at 60°C for 0.5 hours to dilute;

[0188] 2) Add 0.093g of chloroplatinic acid hexahydrate to 0.3ml of a mixed solution of ethylenediamine and water (the volume ratio of ethylenediamine and water is 0.15:1), and stir at 25°C for 5 hours to obtain [ Pt(NH 2 CH 2 CH 2 NH 2 ) 2 ] 2+ solution; 0.21g of zinc nitrate hexahydrate was added to a mixed solution of 0.6ml of ethylenediamine and water (the volume ratio of ethylenediamine and water was 0.3:1), and after stirring for 1 hour at 60°C, [Zn (NH 2 CH 2 CH 2 NH 2 ) 2 ](NO 3 ) 2 solution.

[0189] 3) Add the complex solution obtained in step 2) to the soluti...

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Abstract

The invention discloses a catalyst as well as a preparation method and application thereof. The catalyst comprises a carrier and an active component, the carrier is a pure silicon molecular sieve, andthe active element in the active component comprises Pt,wherein Pt is loaded in the carrier in the form of a sub-nano Pt cluster (the number of Pt atoms in the cluster is 1-10, and the average numberof Pt atoms is 3), zn is linked with the carrier through a Zn-O-Si bond in the form of unit point + divalent Zn ions, and is connected with the platinum cluster through a Zn-O-Pt bond. The preparation method of the catalyst adopts the direct hydrogen reduction, the prepared catalyst encapsulates the sub-nano platinum clusters and the unit point Zn <2 +> ions into a pure silicon molecular sieve, and the catalyst is applied to the propane dehydrogenation catalytic reaction and shows the performance far higher than that of other catalysts.

Description

technical field [0001] The application relates to a catalyst and its preparation method and application, belonging to the field of catalysts. Background technique [0002] Propylene is one of the most important feedstocks in global business, vital to the production of a wide range of valuable chemicals, commodities and fuels. Due to the scarcity of fossil fuels and the discovery of shale gas, propane dehydrogenation (PDH) is gaining popularity and is considered as a more promising method to meet the growing global demand for propylene. Platinum-based catalysts are widely used in industrial PDH processes, but platinum-based catalysts often suffer from rapid deactivation and unsatisfactory propylene selectivity. The size of metal nanoparticles is a key factor affecting the conversion of PDH, and reducing the particle size is beneficial to expose more metal active sites, thereby increasing the conversion rate of propane. Al 2 o 3 , SiO 2 etc. are the most commonly used car...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/035B01J37/10B01J37/18C07C5/333C07C11/06
CPCB01J29/0354B01J37/0009B01J37/0018B01J37/10B01J2229/18C07C5/3337C07C11/06Y02P20/52
Inventor 于吉红孙启明王宁
Owner JILIN UNIV
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