Photocatalytic metal-molecular sieve composite catalyst and preparation method thereof

A composite catalyst and molecular sieve technology, which is applied in molecular sieve catalysts, physical/chemical process catalysts, chemical instruments and methods, etc., can solve the problems of high photon energy and inability to directly use solar energy, and achieve low equipment requirements and low photon Low energy threshold and low solvent pollution

Inactive Publication Date: 2012-08-22
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although people have made great progress in using photocatalytic conversion of methane under mild conditions, so far, the highest conversion rate of methane is only 5.9%; in addition, the photon energy required to drive photocatalytic methane conversion is too high ( Ultraviolet light with a wavelength of less than 270 nanometers), which cannot directly use the energy of sunlight reaching the earth's surface (the shortest wavelength is greater than 290 nanometers)

Method used

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  • Photocatalytic metal-molecular sieve composite catalyst and preparation method thereof
  • Photocatalytic metal-molecular sieve composite catalyst and preparation method thereof
  • Photocatalytic metal-molecular sieve composite catalyst and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0039] Dissolve 0.1g of sodium metaaluminate in 20mL of deionized water, add 8mL of tetrapropylammonium hydroxide (TPAOH, 25wt%) and 7mL of tetrapropylammonium hydroxide (TPAOH, 25wt%) and 7mL of ethyl orthosilicate to the solution, and stir at room temperature for 12 hours until the solution is clear . The obtained solution was transferred to a stainless steel reactor with a polytetrafluoroethylene liner, and placed in an oven at 180°C for crystallization in a static state. After 8 days, the reactor was taken out and naturally cooled to room temperature. The product obtained in the reactor was filtered, washed ultrasonically and then dried at 110°C. Put the dried white powder in a high-temperature tube furnace, slowly raise the temperature (2°C / min) to 600°C for 10 hours in an oxygen atmosphere, and then cool naturally to room temperature to obtain a sodium microporous molecular sieve (NaZSM-5 ).

[0040] Weigh 5g of the powder and disperse it in 200mL ammonium chloride sol...

Embodiment 2

[0046] Under argon protection, 1.0 g of metal-molecular sieve composite photocatalyst was evenly spread in a closed quartz reactor (reactor volume: 25 cm 3 ), then the reaction system was evacuated, and 1000 μmol of high-purity methane gas (>99.995%) was introduced to test the photocatalytic performance, and the catalytic product was collected online by gas chromatography for quantitative analysis. Such as Figure 4 Shown is the change curve of the amount of methane conversion with the light time at room temperature. It can be seen that the photocatalyst has a good catalytic methane conversion effect under different ultraviolet light source (high pressure mercury lamp or outdoor sunlight) irradiation conditions. For example, using a high-pressure mercury lamp as an irradiation source, each gram of catalyst per hour can catalyze 10.2 μmol of methane.

[0047] The molar ratio of the catalyst components prepared in this embodiment is Zn 0.7 AlSi 15 o 32 or CD 0.7 AlSi 15 o...

Embodiment 3

[0050] Under argon protection, 1.0 g of metal-molecular sieve composite photocatalyst was evenly spread in a closed quartz reactor (reactor volume: 25 cm 3 ), then the reaction system was evacuated, and 1000 μmol of high-purity oxygen (>99.99%) was introduced. After contacting at room temperature for 1 hour, remove excess oxygen, take 50 mg of catalyst in a hand box and seal it in a paramagnetic tube for magnetic measurement.

[0051] The molar ratio of the catalyst components prepared in this embodiment is Zn 0.7 AlSi 15 o 32 or CD 0.7 AlSi 15 o 32 , with a complete MFI molecular sieve configuration, after one hour of ultraviolet light irradiation, each gram of the catalyst can produce 3.7X 10 16 a monovalent metal zinc ion or cadmium ion.

[0052] Such as Figure 6 Shown are the electron spin resonance spectra of the catalyst before and after exposure to oxygen. It can be clearly seen from the spectra that after mutual contact, each oxygen molecule captures a single ...

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Abstract

The invention provides a photocatalytic metal-molecular sieve composite catalyst and a preparation method thereof, and belongs to the technical field of methane catalysis. The catalyst prepared by the method can generate a large quantity of stable monovalent metal cations (Zn+ or Cd+) through ultraviolet radiation, thus the catalyst has extremely high photocatalytic methane conversion activity; and driven by sunlight, the catalyst can efficiently catalyze methane to couple thereby producing ethane and meanwhile generate equimolar hydrogen under normal temperature and normal pressure. Comparedwith the existing methane conversion photocatalyst, the catalyst has the advantages of the highest methane conversion ratio (23.5%), the highest ethane selectivity (99.7%), the minimum photon energy requirement (wavelength is less than 390nm) and the like.

Description

technical field [0001] The invention relates to a catalyst in the technical field of methane catalysis and a preparation method thereof, in particular to a metal-molecular sieve composite catalyst with high-efficiency photocatalytic methane conversion performance and a preparation method thereof. Background technique [0002] Methane is the main component of natural gas and is abundant in reserves. As a potentially important carbon source, methane can replace dwindling petroleum resources for chemical production. However, the chemical properties of methane are very stable, so it cannot be directly used as a raw material for chemical production. To convert methane into more active derivatives, various catalytic methane conversion strategies and corresponding catalysts have been developed. At present, the existing strategies mainly use thermal energy to drive the catalytic reaction, such as steam methane reforming to synthesis gas and methane coupling to ethane under anaerob...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J29/40C07C2/76C07C9/06
CPCY02P20/10
Inventor 陈接胜李路李国栋王开学
Owner SHANGHAI JIAO TONG UNIV
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