ZSM-5 molecular sieve limited rhodium monatomic catalyst and preparation method thereof

A technology of ZSM-5 and molecular sieve, which is applied in the field of ZSM-5 molecular sieve-limited rhodium single-atom catalysts and its preparation, can solve the problems of poor high-temperature stability of single-atom rhodium catalysts, low utilization rate of rhodium, and high preparation costs, and achieve simple preparation methods , reduce the preparation cost and improve the utilization rate

Active Publication Date: 2018-04-10
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the technical problems of high preparation cost of conventional rhodium-based catalysts, low utilization rate of rhodium, and poor high-temperature stability of single-atom rhodium catalysts in the prior art, the present invention provides a catalyst with high catalytic activity, good thermal stability and sufficient energy Utilizing ZSM-5 molecular sieves per rhodium atom to limit rhodium single-atom catalysts and its preparation method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Dissolve 19.3mL of tetraethyl orthosilicate, 0.53g of sodium metaaluminate, and 13.2g of tetrapropylammonium hydroxide in 100mL of deionized water, adjust the pH to 13 with sodium hydroxide, rotate at 200rpm, and at 50°C, magnetically After stirring for 30 min, a gel was obtained. Dissolve 0.11 g of rhodium dicarbonyl acetylacetonate in 10 mL of deionized water, slowly add dropwise to the above gel at 0.03 mL / s, and magnetically stir at 100 °C for 2 h at 500 rpm. The obtained gel was transferred to a hydrothermal kettle, crystallized at 120 °C for 10 h, the solid was collected, and washed with deionized water until the filtrate was neutral. The solid sample was placed in a high-temperature furnace and treated at 150° C. for 2 hours under a carbon monoxide atmosphere to obtain a single-atom rhodium catalyst defined by ZSM-5.

[0020] Catalytic performance evaluation: The reaction was carried out in a fixed-bed reactor with continuous sampling, the reaction temperature w...

Embodiment 2

[0022] Dissolve 5.13g of fumed silica, 0.89g of aluminum isopropoxide, and 9.3g of tetrapropylammonium hydroxide into 150mL of deionized water, adjust the pH to 10 with sodium hydroxide, and stir magnetically at 80°C at 600rpm After 60 min, a gel was obtained. Dissolve 0.22 g of potassium hexachlororhodium in 10 mL of deionized water, slowly add it dropwise to the above gel at 0.05 mL / s, and stir magnetically at 100 °C for 4 h at 600 rpm. The obtained gel was transferred to a hydrothermal kettle, crystallized at 100 °C for 24 h, the solid was collected, and washed with deionized water until the filtrate was neutral. The solid sample was placed in a high-temperature furnace and treated at 100°C under an ethylene atmosphere for 4 hours to obtain a single-atom rhodium catalyst defined by ZSM-5.

[0023] Catalytic performance evaluation: The reaction was carried out in a fixed-bed reactor with continuous sampling, the reaction temperature was 700°C, and the raw material gas consi...

Embodiment 3

[0025] Dissolve 7ml of silica gel (30wt%), 1.62g of aluminum nitrate, and 6.5g of cetyltrimethylammonium bromide into 120mL of deionized water, adjust the pH to 12 with sodium hydroxide, and rotate at 300rpm at 60°C. Stir magnetically for 30 min to obtain a gel. Dissolve 0.057g of tris(ethylenediamine)rhodium trichloride in 10mL of deionized water, slowly add it dropwise to the gel in step 1 at 0.03mL / s, and stir magnetically at 100°C for 3 h at 300rpm . The obtained gel was transferred to a hydrothermal kettle, crystallized at 120 °C for 12 h, the solid was collected, and washed with deionized water until the filtrate was neutral. The solid sample was placed in a high-temperature furnace and treated at 180° C. for 3 h under a propylene atmosphere to obtain a single-atom rhodium catalyst defined by ZSM-5.

[0026] Catalytic performance evaluation: The reaction was carried out in a fixed-bed reactor with continuous sampling, the reaction temperature was 700°C, and the raw mat...

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PUM

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Abstract

The invention relates to a preparation method of a ZSM-5 molecular sieve limited rhodium monatomic catalyst. The technical problems that in the prior art, the precious metal catalyst preparation costis high, the atom utilization rate is low, and the high-temperature reaction stability is poor are solved. The ZSM-5 molecular sieve limited rhodium monatomic catalyst is obtained through the steps that a rhodium-containing radical group is dispersed in a ZSM-5 molecular sieve through one-step crystallization, calcination is conducted in a fixed atmosphere in a high temperature furnace, the rhodium radical group can be promoted to be decomposed into rhodium atoms, and single atoms in the molecular sieve are dispersed. Accordingly, the catalyst preparation method is simple, the utilization rateof the precious metal rhodium is increased, the preparation cost of the rhodium-based catalyst is lowered, the stability of the rhodium atoms is improved, and the service life of the catalyst is prolonged. The catalyst has the channel confinement effect and the size effect simultaneously, the pyrolysis capacity of methane in the active site can be improved, and a methane synthesis gas reaction can be greatly promoted.

Description

technical field [0001] The invention relates to the technical fields of natural gas chemical industry and coal chemical industry, in particular to a ZSM-5 molecular sieve limited rhodium single-atom catalyst and a preparation method thereof. Background technique [0002] With the successful exploitation of combustible ice and shale gas, the utilization of natural gas resources has attracted increasing attention. At present, the relatively mature technology of methane utilization is to convert it into synthesis gas. The processes for converting natural gas into synthesis gas include steam reforming, carbon dioxide reforming and partial methane oxidation. For the three reaction noble metal catalysts, they all have good catalytic effects, especially rhodium-based catalysts, which have anti-sintering and anti-carbon deposition properties that transition metals do not have. However, precious metal resources are scarce and expensive, resulting in high catalyst preparation costs....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/44B01J37/03B01J37/10B01J37/08G01N31/10
CPCB01J29/44B01J37/036B01J37/08B01J37/10B01J2229/186G01N31/10
Inventor 丁传敏王俊文贾艳明郭松松薛亚楠高志婷
Owner TAIYUAN UNIV OF TECH
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