阅读说明：本技术 一种真空合成二硫化钼的方法 (Method for synthesizing molybdenum disulfide in vacuum ) 是由 王飞 陈钰臻 陆从理 杨斌 刘大春 徐宝强 邓勇 曲涛 田阳 熊恒 郁青春 蒋 于 2021-08-18 设计创作，主要内容包括：本发明公开一种真空合成二硫化钼的方法,将MoO-(3)粉末和S粉混合均匀后放到石英管中,将石英管在真空度为2～20Pa条件下,用封管机进行密封,将密封后的石英管进行热处理,冷却后取出石英管,石英管内产物为MoS-(2),收率最高可达91.89％,可直接用作润滑剂；本发明采用真空合成的方式将氧化钼硫化为二硫化钼,该方法同时可以用于过渡金属氧化物的硫化,具有成本低、流程短、操作简便、收率高,对环境污染小的优点。(The invention discloses a method for synthesizing molybdenum disulfide in vacuum, which is to mix MoO 3 Uniformly mixing the powder and the S powder, placing the mixture into a quartz tube, sealing the quartz tube by using a tube sealing machine under the condition that the vacuum degree is 2-20 Pa, carrying out heat treatment on the sealed quartz tube, cooling and taking out the quartz tube, wherein the product in the quartz tube is MoS 2 The yield can reach 91.89% at most, and the product can be directly used as lubricant; the method adopts a vacuum synthesis mode to sulfurize molybdenum oxide into molybdenum disulfide, can be used for sulfurizing transition metal oxides, and has the advantages of low cost, short flow, simple and convenient operation, high yield and small environmental pollution.)

1. A method for synthesizing molybdenum disulfide in vacuum is characterized by comprising the following specific steps:

adding MoO₃Uniformly mixing the powder and the S powder, placing the mixture into a quartz tube, sealing the quartz tube by using a tube sealing machine under the condition that the vacuum degree is 2-20 Pa, carrying out heat treatment on the sealed quartz tube, cooling and taking out the quartz tube, wherein the product in the quartz tube is MoS₂。

2. The method for vacuum synthesis of molybdenum disulfide as claimed in claim 1, wherein MoO₃The purity of the powder is 99.95 percent, and the S powder is industrial sulfur powder.

3. The method for vacuum synthesis of molybdenum disulfide as claimed in claim 1, wherein MoO₃The mass ratio of the powder to the S powder is 1: 1-3.

4. The method for synthesizing molybdenum disulfide under vacuum according to claim 1, wherein the sealing pressure of the quartz tube is 2-20 Pa, and the inner diameter of the quartz tube is 10-30 mm.

5. The method for synthesizing molybdenum disulfide in vacuum according to claim 1, wherein the heat treatment is carried out by heating to 500-600 ℃ and then holding for 10-30 min.

Technical Field

The invention relates to a method for synthesizing molybdenum disulfide in vacuum, belonging to the technical field of vacuum metallurgy.

Background

The transition metal sulfide has a crystal structure similar to that of graphene and a band gap structure which is not contained in graphene, so that the transition metal sulfide has unique physical, chemical and photoelectric properties and becomes a research hotspot in new materials. Molybdenum disulfide can still keep better lubricating property under the environmental conditions of high temperature, high pressure and high-speed rotation, is known as lubricant king, and is widely applied to high and new technical fields of aerospace, military industry, nuclear industry and the like. The industrial production of molybdenum disulfide is mainly a chemical synthesis method, the raw materials used are different, generally ammonium molybdate is used as raw material, the ammonium molybdate is vulcanized and converted into ammonium thiomolybdate, and then MoS is prepared by thermal decomposition of the ammonium thiomolybdate₂In addition, molybdenum trioxide can be directly reacted with industrial sulfur powder to generate MoS₂And the like.

The patent with application number 201410314766.7 takes ammonium molybdate as a raw material and thiourea as a sulfur source to carry out vulcanization to generate MoS₃Precipitating, centrifuging, and thermally decomposing to obtain MoS₂The production process is long, the preparation conditions are severe, and the size and the shape of the product are difficult to regulate and control, so that the method is not suitable for large-scale production and application.

HL A et al utilize molybdenum trioxide to directly react with industrial sulfur powder, and free MoO in the product₃With incompletely vulcanised MoO₂Becomes main impurities, and the sulfur content is unstable, so that the content ratio of Mo and S is unstable, and the subsequent use of the product is influenced to a certain extent. Meanwhile, no matter what method, the method can cause a great amount of loss of raw materials, doping of components in the product,Low yield, complex collection process, great environmental pollution, high production cost and the like.

Disclosure of Invention

Aiming at the problems and the defects in the prior art, the invention provides a method for synthesizing molybdenum disulfide in vacuum, which takes molybdenum oxide (99.95%) and industrial sulfur powder as raw materials, uniformly mixes the raw materials according to a certain proportion, then puts the raw materials into a quartz tube, seals the quartz tube under the vacuum condition, and then heats the quartz tube to directly obtain the product molybdenum disulfide.

A method for synthesizing molybdenum disulfide in vacuum comprises the following specific steps:

(1) adding MoO₃Uniformly mixing the powder and the S powder;

(2) putting the powder obtained in the step (1) into a quartz tube, and sealing the quartz tube by using a tube sealing machine under the condition that the vacuum degree is 2-20 Pa;

(3) carrying out heat treatment on the sample obtained in the step (2), cooling and taking out the quartz tube, wherein the product in the quartz tube is MoS₂。

The MoO₃The purity of the powder is 99.95 percent; the S powder is industrial sulfur powder.

The MoO₃The mass ratio of the powder to the S powder is 1: 1-3.

When the quartz tube is sealed, the pressure is 2-20 Pa, and the inner diameter of the quartz tube is 10-30 mm.

The heat treatment is carried out by heating to 500-600 ℃ and then preserving the heat for 10-30 min.

According to the formula of vapor pressure and temperature of a substance: lg (P/kPa) ═ a 10³*T^-1+B*lgT+c*10^-3+ D, calculating the volatilization temperature of molybdenum trioxide under the condition of 1-120 Pa, as shown in FIG. 1, it is known that the temperature required for the molybdenum trioxide to volatilize increases significantly with the increase of the saturated vapor pressure, and when the pressure is 2-20 Pa, the corresponding volatilization temperature is: 890K to 950K; it is known that vacuum conditions can significantly reduce the temperature required for the reaction.

Utilizing Factsage to calculate MoO under the condition of 10Pa₃The binary equilibrium phase diagram-S, as shown in FIG. 2, shows the reaction temperature for producing molybdenum disulfide at 10PaAbout 700K to 1490K, and is required to participate in the reaction MoO₃The mass ratio of S to S is: the ratio of the molybdenum disulfide to the water is 1: 0.125-9, so that gas-solid reaction is carried out to generate molybdenum disulfide under the condition of setting the pressure to be 2-20 Pa, and the reaction temperature can be set to be 500-600 ℃.

Meanwhile, according to the binary equilibrium phase diagram, under the condition that S participates in less reaction, MoO is generated₂、MoS₃The intermediate products are stored under vacuum condition, the reaction temperature is set to be 500-600 ℃, and MoO is controlled₃The mass ratio of the powder to the S powder is 1: 1-3, and the reaction under the conditions is as follows: MoO₃+3.5S(g)＝MoS₂+1.5SO₂(g) The sulfur powder is quickly volatilized to be changed into gas under the vacuum condition, so that the reaction heat preservation time can be controlled within 10-30 min, the molybdenum trioxide is completely vulcanized into the molybdenum disulfide, no intermediate product is generated, and the vacuum sealing can obtain higher yield at lower temperature and shorter heat preservation time.

The invention has the advantages that the process flow is simple, the operation is convenient, the vulcanization process is carried out in a closed quartz tube, the process can realize the full reaction of molybdenum oxide and sulfur, the use amount of industrial sulfur powder is greatly reduced, and MoS is generated₂No new impurity is generated in the process, and the product quality is high. Because the reaction is carried out under the vacuum condition, the reaction temperature of the raw materials is obviously reduced, and the method has the advantages of economy, environmental protection, high reaction speed, low energy consumption and the like; from the analysis of the principle of vulcanization, the raw material used in this method is not limited to molybdenum trioxide, but can be used for the vulcanization of transition metal oxides such as tungsten trioxide.

Drawings

FIG. 1 is MoO₃The relationship of saturated vapor pressure to temperature;

FIG. 2 shows MoO₃And a binary equilibrium phase diagram of S under the condition of 10 Pa;

figure 3 is the XRD pattern of the product of example 1.

Detailed Description

The invention will be further illustrated with reference to specific examples, but the scope of the invention is not limited thereto.

Example 1

A method for synthesizing molybdenum disulfide in vacuum comprises the following specific steps:

(1) mixing raw materials: weighing MoO according to the mass ratio of 1:1₃Weighing the powder and S powder, uniformly mixing the weighed raw materials to prepare a plurality of parts of mixed powder; wherein MoO₃The purity of the powder is 99.95 percent, and the sulfur powder is industrial sulfur powder;

(2) vacuum tube sealing: respectively putting a plurality of parts of powder obtained in the step (1) into a plurality of quartz tubes, wherein the inner diameter of each quartz tube is 10mm, and sealing the quartz tubes by using a tube sealing machine under the condition of 10Pa of vacuum degree;

(3) putting the sample obtained in the step (2) into an internal heating type vacuum furnace, heating to 500 ℃ under the pressure of 10Pa, preserving the heat for 30min, and taking out a quartz tube after cooling; the MoS obtained₂The product mass was 0.89g, and the yield was 80.18%.

FIG. 3 is the XRD pattern of the product of step (3) in this example, from which the characteristic peaks and MoS of the product can be seen₂Complete match, which indicates MoO in the vacuum vulcanization process₃All converted into MoS₂. The prepared molybdenum disulfide is widely used for lubricants, lithium battery super capacitors, photocatalysts, synthetic nano composite materials and the like.

Example 2

A method for synthesizing molybdenum disulfide in vacuum comprises the following specific steps:

(1) mixing raw materials: weighing MoO according to the mass ratio of 1:2₃Weighing the raw materials and uniformly mixing the raw materials with the S powder to prepare a plurality of parts of mixed powder; wherein MoO₃The purity of the powder is 99.95 percent, and the sulfur powder is industrial sulfur powder;

(2) vacuum tube sealing: respectively putting a plurality of parts of powder obtained in the step (1) into a plurality of quartz tubes, wherein the inner diameter of each quartz tube is 30mm, and sealing the quartz tubes by using a tube sealing machine under the condition of vacuum degree of 2 Pa;

(3) putting the sample obtained in the step (2) into an internal heating type vacuum furnace, heating to 550 ℃ under the pressure of 2Pa, preserving the heat for 20min, and taking out a quartz tube after cooling; the resulting condensate MoS₂The product mass was 0.96g, and the yield was 86.48%.

Example 3

A method for synthesizing molybdenum disulfide in vacuum comprises the following specific steps:

(1) mixing raw materials: weighing MoO according to the mass ratio of 1:3₃Weighing the raw materials and uniformly mixing the raw materials with the S powder to prepare a plurality of parts of mixed powder; wherein MoO₃The purity of the powder is 99.95 percent, and the sulfur powder is industrial sulfur powder;

(2) vacuum tube sealing: respectively putting a plurality of parts of powder obtained in the step (1) into a plurality of quartz tubes, wherein the inner diameter of each quartz tube is 20mm, and sealing by using a tube sealing machine; wherein the quartz tube is sealed under the condition of vacuum degree of 20 Pa;

(3) putting the sample obtained in the step (2) into an internal heating type vacuum furnace, heating to 600 ℃ under the pressure of 20Pa, preserving the heat for 10min, and taking out a quartz tube after cooling; the resulting condensate MoS₂The product mass was 1.02g, and the yield was 91.89%.

Comparative example 1

Now will MoO₃Weighing raw material MoO and S powder according to the mass ratio of 1:5₃Mixing with S powder, directly placing into an open graphite crucible, placing the graphite crucible into a vacuum furnace at 10Pa, heating to 800 deg.C, and keeping the temperature for 60min to obtain MoO powder₂And MoS₂The mixture weighed 0.55g, and the yield was 49.54%.

Comparative example 2

Preparation of MoS by traditional vapor deposition method₂Adding MoO₃Weighing the powder and S powder according to the mass ratio of 1:10, respectively placing the raw materials in two temperature regions of 800 ℃ and 180 ℃, and simultaneously introducing H₂Ar creates reducing atmosphere, and the temperature is kept for 90min at the set temperature to generate MoS₂The mass of the product was 0.76g, and the yield was 68.46%.

In summary, the yields of the products of examples 1-3 of the present invention are higher than those of comparative examples 1 and 2, and MoO is used in the present invention₃After being uniformly mixed with S, the mixture is placed in a quartz tube for vacuum sealing and is roasted in a resistance furnace, the reaction temperature is effectively reduced under the vacuum condition, the raw materials are all reacted without adding excessive sulfur powder, and the product of the embodiment is MoS₂High purity and impurityLess, fine in granularity and without further impurity removal treatment.