High specific surface area tungsten carbide microspheres and load type catalyst and their preparation methods

A supported catalyst and tungsten carbide microsphere technology, applied in the field of material science, can solve the problem of not fully meeting the requirements of catalytic materials, and achieve the effects of aerobic reduction catalytic activity, cost reduction, and uniform particle size distribution.

Inactive Publication Date: 2009-04-29
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The method is to react tungsten powder or tungsten oxide precursor with a mixture of carbon-containing gas and hydrogen at high temperature [SantosJ.B.O., et al.J.Catal., 2002(210): 1-6.], The specific surface area of ​​tungsten carbide prepared by this method is higher than that of the high-temperature solid-state method, but it still cannot fully meet the requirements of catalytic materials.

Method used

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  • High specific surface area tungsten carbide microspheres and load type catalyst and their preparation methods
  • High specific surface area tungsten carbide microspheres and load type catalyst and their preparation methods

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Dissolve 3.0g of glucose in 40ml of water, add 0.85g of ammonium metatungstate under strong stirring, continue stirring and mixing evenly, then transfer to a 50ml hydrothermal reaction kettle. Keep the temperature at 180° C. for 48 hours in a temperature-programmed oven, and cool to room temperature naturally. Filter, wash with water and alcohol, and dry under vacuum at 80°C to obtain a tan tungsten carbide precursor.

[0031] Take 2.0g tungsten carbide precursor in a boat, place it in a high-temperature tube furnace, under the protection of nitrogen, heat up to 1000°C at 5°C / min, and then feed a mixture of nitrogen and hydrogen (V N2 / V H2 =3:1, v=50ml / min) for 5 hours, cooled to obtain tungsten carbide microspheres.

Embodiment 2

[0033] Dissolve 2.0 g and 0.9 g of sucrose and ammonium metatungstate in 20 ml of water respectively, mix the two solutions evenly under stirring, and transfer them into a 50 ml hydrothermal reaction kettle. Keep the temperature at 150° C. for 10 hours in a temperature-programmed oven, and cool to room temperature naturally. Filter, wash with water and alcohol, and dry under vacuum at 80°C to obtain a tan tungsten carbide precursor.

[0034]Take 1.0 g of tungsten carbide precursor in a boat, place it in a high-temperature tube furnace, under the protection of nitrogen, heat up to 1100 °C at 3 °C / min, and then feed a mixture of nitrogen and hydrogen (V N2 / V H2 =2:1, v=30ml / min) for 10 hours, cooled to obtain tungsten carbide microspheres. attached figure 1 The scanning electron microscope image of tungsten carbide microspheres prepared by this method shows that the product is a regular spherical shape with a particle size of about 1 μm and uniform distribution.

Embodiment 3

[0036] Dissolve 3.0 grams of glucose in 40ml of water, add 0.45g of pertungstic acid solution under strong stirring, continue to stir and mix evenly, then transfer to a 50ml hydrothermal reaction kettle. Keep the temperature at 180° C. for 48 hours in a temperature-programmed oven, and cool to room temperature naturally. Filter, wash with water and alcohol, and dry under vacuum at 80°C to obtain a tan tungsten carbide precursor.

[0037] Take 2.5g tungsten carbide precursor in a boat, place it in a high-temperature tube furnace, under the protection of nitrogen, heat up to 1400°C at 5°C / min, then feed a mixture of nitrogen and acetylene (V N2 / V C2H2 =4:1, v=50ml / min) for 8 hours, cooled to obtain tungsten carbide microspheres.

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Abstract

The invention discloses a tungsten carbide micro-ball with high specific area, a load-typed catalyst and a preparation method thereof. The preparation method used for the tungsten carbide micro-ball with high specific area comprises the steps as follows: (1) carbon sources and tungsten sources are used for synthesizing a precursor of the tungsten carbide micro-ball by a water-heating method; and (2) under reduction gas, the precursor obtained in step (1) is disposed at high temperature so as to obtain the tungsten carbide micro-ball. The preparation method used for the load-typed catalyst comprises the steps as follows: the prepared tungsten carbide micro-ball is taken and arranged in a beaker; solvent is added into the beaker and dispersed by ultrasonic; under the mixing process, precursor of the active metal with suitable quantity is added into the beaker and dispersed by ultrasonic; the pH value is adjusted to more than 10 by NaOH solution; the beaker is arranged in a microwave oven subsequently, alternatively heated and cooled to room temperature; the pH value is then adjusted to 2-3 by HCl solution; and the solution is mixed, filtrated, dried and grinded subsequently so as to prepare the load-typed catalyst. The prepared tungsten carbide micro-ball has uniform distribution of particle size and high specific surface area; the load-typed catalyst has synergistic effect, structural effect and better oxygen reduction catalytic activity.

Description

technical field [0001] The invention relates to the field of material science, in particular to a preparation method of tungsten carbide microspheres with a high specific surface area and a supported catalyst with tungsten carbide microspheres as a carrier. Background technique [0002] As early as 1781, Scheele first discovered tungsten carbide, and it was not until more than a hundred years later that Henri Moissan synthesized tungsten carbide artificially. Tungsten carbide is an interstitial compound formed by interstitial carbon atoms in the tungsten lattice. This carbide material has unique physical and chemical properties. Their properties combine the properties of three types of materials: covalent compounds, ionic crystals and transition metals. They have the high strength, hardness and brittleness of covalent compounds, the high melting point and simple crystal structure of ionic crystals, and their electrical and magnetic properties are similar to metals [Jiang G....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J35/08B01J35/10B01J32/00B01J27/22
Inventor 沈培康王毅宋树芹
Owner SUN YAT SEN UNIV
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