Method for preparing mesoporous needle-shaped tungsten carbide

A tungsten carbide and needle-like technology is applied in the field of preparation of mesoporous needle-like tungsten carbide, which can solve the problems of hard agglomeration and the decrease of catalyst active surface, and achieve the effects of high specific surface area, reduction of phase-forming temperature, and increase of catalytic activity.

Inactive Publication Date: 2011-06-29
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Nowadays, the preparation of nano-tungsten carbide mostly adopts the method of polymerizing and separating organic matter. During this period, not only will organic molecules be introduced and excess carbon will be left in the later reaction, resulting in a decline in the active surface of the catalyst, but also hard agglomeration during the calcination process.

Method used

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  • Method for preparing mesoporous needle-shaped tungsten carbide
  • Method for preparing mesoporous needle-shaped tungsten carbide
  • Method for preparing mesoporous needle-shaped tungsten carbide

Examples

Experimental program
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Embodiment 1

[0036] Control the ambient temperature at 10°C, take 10g each of ammonium metatungstate and ammonium carbonate, put them into a mortar and mix them evenly, after grinding for 3 minutes, pour the mixed powder into an open culture vessel, add 200ml of deionized water, and stir with a glass rod for 3 After standing for 18 hours, it was centrifuged, washed three times with deionized water, and dried at room temperature. The obtained ammonium metatungstate crystals are needle-shaped elongated crystals. The obtained ammonium metatungstate crystal was photographed, and the figure 1 It can be seen that the obtained crystals are needle-like elongated crystals. And do AFM atomic force scanning probe to analyze the surface morphology, by figure 2 It can be seen that the surface is smooth and the crystallization is ideal. Then CO, H with a volume ratio of 1:2 2 The mixed gas is a reducing carbonization gas, and it is carbonized at 800 °C for 4 hours in a one-step method with a progra...

Embodiment 2

[0038] Control the ambient temperature at 10°C, take 10g of ammonium metatungstate and 5g of ammonium carbonate, put them into a mortar and mix them evenly, after grinding for 3 minutes, pour the mixed powder into an open culture vessel, add 180ml of deionized water, and oscillate ultrasonically for 3 minutes , after standing for 24 hours, centrifuged, washed three times with deionized water, and dried at room temperature. The obtained ammonium metatungstate crystals are needle-shaped elongated crystals. Then CO, H with a volume ratio of 1:2 2 The mixed gas is a reducing carbonization gas, and the carbonization is carried out at 800°C for 4 hours at a temperature of 6°C / min as a programmed temperature rise rate in a one-step method to obtain mesoporous acicular tungsten carbide. The average length of mesoporous acicular tungsten carbide is 1.2mm.

Embodiment 3

[0040] Control the ambient temperature at 15°C, take 10g of ammonium metatungstate and 5g of ammonium carbonate, put them into a mortar and mix them evenly, after grinding for 3 minutes, pour the mixed powder into an open culture vessel, add 180ml of deionized water, and oscillate ultrasonically for 3 minutes , after standing for 24 hours, centrifuged, washed three times with deionized water, and dried at room temperature. The obtained ammonium metatungstate crystals are needle-shaped elongated crystals. Then CO, H with a volume ratio of 1:2 2 The mixed gas is a reducing carbonization gas, and it is carbonized at 800 °C for 2 hours at a temperature of 6 °C / min as a temperature program in a one-step method to obtain mesoporous needle-shaped tungsten carbide. The average length of mesoporous acicular tungsten carbide is 1.3mm.

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Abstract

The invention discloses a method for preparing mesoporous needle-shaped tungsten carbide. The preparation method comprises the following steps of: controlling the ambient temperature to be 10-30 DEG C; adding deionized water into ammonium meta-tungstate and ammonium carbonate which has a mass ratio of 1:0.75-2, for preparing a precursor culture solution in which the total mass fraction of the ammonium meta-tungstate and the ammonium carbonate is 2.5-50 wt%; stirring the precursor culture solution for 1-15 minutes, then placing the precursor culture solution in an open system for 2-24 hours, and obtaining self-growing ammonium meta-tungstate needle-shaped crystal after centrifuging and drying; and carrying out one-step reduction and carbonization of the self-growing ammonium meta-tungstateneedle-shaped crystal in a hydrogen-rich atmosphere, and thus obtaining the mesoporous needle-shaped tungsten carbide. The mesoporous needle-shaped tungsten carbide prepared by the preparation methodis formed by the piling of nano-tungsten carbide grains, has controllable crystal length, well-developed aperatures, is simply prepared and operated and can be well used in the crystallization field.

Description

(1) Technical field [0001] The invention relates to a preparation method of tungsten carbide, in particular to a preparation method of mesoporous acicular tungsten carbide formed by stacking nanometer tungsten carbide particles. (2) Background technology [0002] As a non-precious metal catalytic material with excellent performance, tungsten carbide (WC) has been widely used in catalysis since it was reported in the 1960s that it had good catalytic activity for cyclohexane dehydrogenation and ethylbenzene dehydrogenation to styrene. Potential is in the spotlight. Literature reports pointed out that the surface electron layer of WC is similar to platinum (Pt), and has Pt-like catalytic activity in some reactions. WC not only has the characteristics of replacing platinum and other noble metal catalysts and good anti-poisoning ability, but also has strong acid resistance and good electrocatalytic activity. However, how to further improve the catalytic activity of WC is one of...

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
Owner ZHEJIANG UNIV OF TECH
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