Preparation method of mesoporous hollow sphere-shaped tungsten carbide

A hollow spherical, tungsten carbide technology, applied in the direction of carbide, tungsten/molybdenum carbide, etc., can solve problems such as difficult structural transformation

Active Publication Date: 2012-07-04
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high hardness and high thermal stability of tungsten carbide, it is very difficult to carry out structural transformation of tungsten carbide after forming.

Method used

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  • Preparation method of mesoporous hollow sphere-shaped tungsten carbide
  • Preparation method of mesoporous hollow sphere-shaped tungsten carbide
  • Preparation method of mesoporous hollow sphere-shaped tungsten carbide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] At room temperature, add 5g of ammonium metatungstate to 10ml of deionized water, and disperse by ultrasonication for 5 minutes. Take 250ml of absolute ethanol and pour it into a glass container, then put the glass container filled with absolute ethanol into the ultrasonic wave, and fix it after the ethanol liquid level in the glass container is higher than the ultrasonic medium liquid level. Add the ammonium metatungstate solution dropwise to absolute ethanol at a rate of 3 s at a rate of 5 μl / drop; when the ammonium metatungstate droplet is dropped into ethanol, precipitation occurs after instant granulation, and continues to be dispersed by ultrasound. After filtration, carry out vacuum drying at 40°C to obtain white solid ammonium metatungstate particles, in the volume ratio of 1:1.1 CO / H 2 The obtained ammonium metatungstate crystals were carbonized under atmosphere. According to the 2°C / min program, the temperature was raised to 750°C and kept for 8 hours. Obtai...

Embodiment 2

[0028] At room temperature, add 15g of ammonium metatungstate to 10ml of deionized water, and disperse by ultrasonication for 20 minutes. Take 200ml of absolute ethanol and pour it into a glass container, then put the glass container filled with absolute ethanol into the ultrasonic wave, and fix it after the ethanol liquid level in the glass container is higher than the ultrasonic medium liquid level. Add the ammonium metatungstate solution dropwise to absolute ethanol at 2 μl / drop, with an interval of 4 seconds between each drop; when the ammonium metatungstate droplet is dropped into ethanol, precipitation occurs after instant granulation, and continues to be dispersed by ultrasonication. After filtration, carry out vacuum drying at 45°C to obtain white solid ammonium metatungstate particles, in the volume ratio of 1:1.8 CO / H 2 The obtained ammonium metatungstate crystals were carbonized under atmosphere. According to the 3°C / min program, the temperature was raised to 750°C...

Embodiment 3

[0030] At room temperature, add 20g of ammonium metatungstate to 10ml of deionized water, and disperse by ultrasonication for 30 minutes. Take 250ml of absolute ethanol and pour it into a glass container, then put the glass container filled with absolute ethanol into the ultrasonic wave, and fix it after the ethanol liquid level in the glass container is higher than the ultrasonic medium liquid level. Add the ammonium metatungstate solution dropwise to absolute ethanol at 1 μl / drop, with an interval of 2 seconds between each drop; when the ammonium metatungstate droplet is dropped into ethanol, precipitation occurs after instant granulation, and continues to be dispersed by ultrasonication. After filtration, carry out vacuum drying at 60°C to obtain white solid ammonium metatungstate particles, in the volume ratio of 1:2.5 CO / H 2 The obtained ammonium metatungstate crystals were carbonized under atmosphere. According to the 10°C / min program, the temperature was raised to 900°...

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Abstract

The invention discloses a preparation method of mesoporous hollow sphere-shaped tungsten carbide. The preparation method comprises the following steps: (1) preparing 30%-70% ammonium metatungstate solution at room temperature; (2) fixing a glass container with absolute ethanol in an ultrasonic apparatus, adding the ammonium metatungstate solution obtained in the step (1) at the speed of 1-5 mu l / drop at an interval of 2-8 seconds per drop in the absolute ethanol in the presence of ultrasonic, immediately pelleting and then generating precipitate, dispersing the precipitate by continuous ultrasonic action, and then obtaining ammonium metatungstate particles by filtration and vacuum drying; and (3) carbonizing the obtained metatungstate particles at the atmosphere of CO / H2, and then obtaining the mesoporous hollow sphere-shaped tungsten carbide. The preparation method is simple to operate, the used solvent is clean and environment-friendly, and the prepared metatungstate particles consist of nano tungsten carbide particles.

Description

(1) Technical field [0001] The invention relates to a preparation method of tungsten carbide, in particular to a preparation method of mesoporous hollow spherical tungsten carbide. (2) Background technology [0002] Because the surface electron layer of tungsten carbide (WC) is similar to that of platinum (Pt), it has Pt-like catalytic activity in some reactions. Applications are also getting a lot of attention. Since the 1960s, it has been reported that it has good catalytic activity in the reactions of cyclohexane dehydrogenation and ethylbenzene dehydrogenation to styrene. Tungsten carbide not only has the potential to replace platinum and other noble metal catalysts, but also has strong acid resistance and good thermal stability, which makes it possible to use it as a high-performance catalyst. [0003] In various catalytic reactions, solid catalysts are widely used, and all aspects of the performance of solid catalysts determine the reaction conversion efficiency. Tu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B31/34C01B32/949
Inventor 马淳安陈赵扬赵峰鸣
Owner ZHEJIANG UNIV OF TECH
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