WO2018006827A1

WO2018006827A1 - Composite material comprising graphite coated on surface of manganese oxide and preparation method therefor

Info

Publication number: WO2018006827A1
Application number: PCT/CN2017/091848
Authority: WO
Inventors: 张启辉
Original assignee: 深圳市知赢科技有限公司
Priority date: 2016-07-05
Filing date: 2017-07-05
Publication date: 2018-01-11
Also published as: CN106159289A

Abstract

Provided are a composite material comprising graphite coated on a surface of a manganese oxide and a preparation method therefor. The method comprises: mixing a manganese oxide powder, a carbon source and water until uniform so as to obtain a mixture; and under oxygen-free conditions and under conditions of an atmospheric pressure kept at 2-15 Mpa and a constant temperature of 300ºC-500ºC, heating the mixture and irradiating same using electromagnetic waves, and keeping the temperature for 5-20 hours so as to obtain a powder of the composite material. The composite material overcomes the following problems: a poor electrical conductivity of a manganese oxide, a short service life, a low catalytic efficiency and many side reactions.

Description

Composite material coated with graphite on manganese oxide surface and preparation method thereof

[0001] The present invention relates to the field of composite materials, and in particular to a composite material coated with graphite on a surface of manganese oxide and a preparation method thereof.

Background technique

[0002] A metal air battery is a semi-fuel cell in which a positive electrode consumes oxygen, a negative electrode consumes a metal, and a current is generated by a redox reaction. According to the type of metal consumed by the negative electrode, it is classified into a lithium air battery, an aluminum air battery, a magnesium air battery, and a zinc air battery. Among them, lithium air battery and aluminum air battery are recognized as the battery of choice for the endurance power of pure electric vehicles due to their huge specific energy (8.1kwh/kg) and the convenience of mechanical charging. Received widespread attention. However, since current metal air batteries use precious metals as catalysts, the cost is high and it is difficult to be accepted by the market. Therefore, a series of controlled experiments were carried out using MnO ₂ as a catalyst. The results show that the catalytic activity of MnO ₂ is second only to CoTMPP in the following four common catalysts (Pt, Mn0 ₂ , CoTMPP, LaNiO ₃ ). The advantages of manganese oxide are low price, abundant reserves and environmental friendliness; however, it has the disadvantages of poor conductivity, low catalytic efficiency, many side reactions, and short life. As a catalyst for a metal air battery, it has no practical value. At present, in order to improve the performance of manganese oxide, it is proposed to mount nano manganese oxide on carbon. The use of nanomaterials has a large specific surface area and a quantum effect that increases the catalytic efficiency. However, there has been no improvement in the problems of the service life, conductivity, and side reactions of manganese oxide. During the catalysis process, the nano-n Ο Ο 表面 on the surface may cause side reactions due to excessive activity, resulting in ΜηΟΟΗ, reducing catalytic efficiency and service life. technical problem

[0003] The main object of the present invention is to provide a composite material coated with graphite on a surface of manganese oxide and a preparation method thereof, which overcome the problems of poor conductivity, short service life, low catalytic efficiency and many side reactions of manganese oxide. Problem solution

Technical solution

[0004] The present invention provides a composite material coated with graphite on the surface of manganese oxide, the surface of the manganese oxide is coated with a graphite layer, and the mass ratio of the manganese oxide to the graphite is 1: X, wherein 0.01≤Χ≤1 . [0005] Further, the manganese oxide includes MnO, Mn0 ₂ , Mn ₂ 0 ₃ , Mn ₃ 0 ₄ , Mn ₂ 0 ₅

ΜηΟ

₂ 0 ₇ one or more of them.

Further, a metal compound is further included, and the metal compound is coated on the surface of the manganese oxide.

[0007]

The present invention also provides a method for preparing a composite material coated with graphite on a surface of manganese oxide, comprising the steps of:

[0009] mixing manganese oxide powder, carbon source and water in a container to obtain a mixture;

[0010] Under anaerobic conditions, the gas pressure is maintained at 2-15 MPa, and the temperature is maintained at a constant temperature of 300 ° C to 500 ° C. The mixture is heated and irradiated with electromagnetic waves at a constant temperature of 5-20 Torr to obtain a powder of the composite material.

[0011] Further, the method further includes: grinding, removing iron, and sieving the obtained composite powder.

[0012] Further, in the container, the manganese oxide powder, the carbon source and the water are uniformly mixed, and the step of obtaining the mixture further comprises:

[0013] The stirring power of the vessel was set to 5-80 kW/m 3 and the temperature was set to 50-85 °C.

[0014] Further, the carbon source is an organic substance.

[0015] Further, the carbon source includes one or more of glucose, maltose, sucrose, lactose, and starch.

[0016] Further, the anaerobic condition is nitrogen or an inert gas atmosphere.

[0017] Further, the electromagnetic wave includes one or more of microwave, medium wave, long wave, short wave, laser, infrared, ultraviolet, visible light, alpha ray, beta ray, gamma ray, sound wave, ultrasonic wave, and infrasound wave.

Advantageous effects of the invention

Beneficial effect

[0018] The composite material coated with graphite on the surface of manganese oxide provided by the invention and the preparation method thereof have the following beneficial effects:

[0019] The composite material coated with graphite on the surface of manganese oxide provided by the invention and the preparation method thereof, coated with graphite on the surface of manganese oxide, utilizing the conductivity and hydrophobicity of graphite, improving the catalytic effect of the composite material and improving the composite The conductivity of the material; the use of electromagnetic waves and the combination of heating not only accelerates the formation of the composite, but also avoids the pyrolysis of manganese oxide, and the electromagnetic waves can also activate the powder. Granular surface, avoiding agglomeration of powder material; heat treatment of manganese oxide in an oxygen-free atmosphere can distort the internal lattice of manganese oxide, form holes of oxygen atoms and improve the conductivity of manganese oxide, shorten the electrons in redox reaction The path of the transfer reduces the internal resistance; the surface of the manganese oxide powder particles is coated with a plurality of graphite crystallites to form a plurality of catalytic active sites; and the majority of the manganese oxide powder is rolled into a piece, and a catalytically active network is formed therein. The catalytic efficiency can be improved; the surface of the manganese oxide is coated with a protective layer of graphite, so that it is difficult to generate a MnOOH by side reaction to ensure the stability of the manganese oxide; the hydrophobicity of the graphite is favorable to form a gas-liquid-solid three-phase interface, which is favorable for solid-liquid gas. Three-phase catalysis.

Brief description of the drawing

DRAWINGS

1 is a schematic flow chart of a method for preparing a composite material coated with graphite on a surface of a manganese oxide according to an embodiment of the present invention [0021]

[0022] The implementation, functional features, and advantages of the present invention will be further described with reference to the accompanying drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] It is to be understood that the specific embodiments described herein are merely illustrative of the invention.

[0024] In the embodiment of the present invention, a composite material coated with graphite on a surface of a manganese oxide is provided, wherein a surface of the manganese oxide is coated with a graphite layer, and the mass ratio of the manganese oxide to the graphite is 1: X, wherein 0.01≤X ≤1.

[0025] Manganese oxide has poor conductivity, low catalytic efficiency, many side reactions, and short life. The surface of the manganese oxide is coated with a graphite layer, and the conductivity and hydrophobicity of the graphite are utilized to enhance the catalytic effect of the composite material. Improve the conductivity of the composite material; the surface of the manganese oxide powder particles is coated with a plurality of graphite crystallites to form a plurality of catalytic active points; most of the manganese oxide powder is rolled into a piece, and a catalytic active network is formed inside, thereby improving Catalytic efficiency; The surface of manganese oxide is coated with a protective layer of graphite, so it is difficult to generate MnOOH by side reaction to ensure the stability of manganese oxide; graphite hydrophobicity is favorable to form a gas-liquid-solid three-phase interface, which is beneficial to solid-liquid three-phase catalytic.

Further, the above manganese oxide includes, but is not limited to, MnO, Mn0 ₂ , Mn ₂ 0 ₃ , Mn ₃ 0 ₄ , Mn ₂ O 5 , MnO.

₂ 0 ₇ one or more of them. Further, a metal compound is further included, and the metal compound is coated on the surface of the manganese oxide powder. The composition of the metal compound is M ₂ O _x , M(OH) _x or MO(OH) _x , wherein M is a metal element, wherein 1≤X≤7, and at least one metal element in the metal compound, the metal compound may also A mixture of a plurality of metal compounds.

[0028] Further, the metal element is a metal element of the fourth and fifth periods of the periodic table of the chemical elements.

[0029] coating the surface of the manganese oxide powder with a metal compound not only increases the conductivity of the manganese oxide, but also forms a plurality of catalytic active sites; the manganese oxide powder is rolled into a sheet, and a catalytically active network is formed therein. The catalytic efficiency can be improved; the surface of the manganese oxide has a protective layer of a metal compound, and it is difficult to generate a side reaction to form MnOOH, thereby ensuring the stability of the manganese oxide and prolonging the service life of the manganese oxide.

[0030] The metal oxide may be coated on the surface of the manganese oxide powder together with carbon, thereby improving the electrical conductivity, catalytic efficiency, and prolonging the service life of the composite material.

[0031] Referring to FIG. 1, a method for preparing a composite material coated with graphite on a surface of manganese oxide is provided in the embodiment of the present invention, which includes the following steps:

[0032] Step S1, mixing manganese oxide powder, carbon source and water in a vessel to obtain a mixture; the vessel may be a reaction vessel.

[0033] Step S2, under an anaerobic condition, the air pressure is maintained at 2-15 MPa, and the temperature is maintained at a constant temperature of 300 ° C to 500 ° C. The mixture is heated and irradiated with electromagnetic waves at a constant temperature of 5-20 Torr to obtain a powder of the composite material. Body, a catalyst with good electrical conductivity, long service life, high catalytic efficiency and few side reactions.

[0034] Electromagnetic waves and heating cause the carbon source to form graphite and coat the surface of the manganese oxide powder to form a composite material. The use of electromagnetic waves and heating means not only accelerates the formation process of the composite material, but also avoids the high temperature decomposition of manganese oxide. The same electromagnetic wave can also activate the surface of the powder particles to avoid agglomeration of the powder material. Under the anaerobic atmosphere The heat treatment of manganese oxide can distort the internal lattice of the manganese oxide, form holes of oxygen atoms and improve the conductivity of the manganese oxide, shorten the path of electron transfer in the redox reaction, and reduce the internal resistance. In this embodiment, this step is implemented in an electric resistance furnace.

[0035] Further, after obtaining the powder of the composite material, the method further comprises: grinding, removing iron and sieving the obtained composite material powder.

[0036] Further, in the above step S1, the manganese oxide powder, the carbon source and the water are uniformly mixed in the container, and the step of obtaining the mixture further comprises: [0037] The stirring power of the vessel was set to 5 to 80 kW/m 3 and the temperature was set to 50 to 85 °C. In this embodiment, the container is a reaction kettle.

[0038] Further, the carbon source is an organic substance. The organic substance may be either water-soluble or insoluble in water. In the present embodiment, a water-soluble organic substance is preferred.

Further, the above carbon source includes one or more of glucose, maltose, sucrose, lactose, and starch. In the present embodiment, sucrose and glucose are preferred as the starting materials for the preparation.

[0040] Further, the above oxygen-free condition is a nitrogen gas or an inert gas atmosphere; heat treatment of the manganese oxide in an oxygen-free atmosphere may cause lattice distortion inside the manganese oxide, form holes of oxygen atoms, and improve conductivity of the manganese oxide. , shorten the path of electron transfer in the redox reaction, reduce internal resistance.

[0041] Further, the electromagnetic wave includes microwave, medium wave, long wave, short wave, laser, infrared, ultraviolet

One or more of visible light, alpha ray, beta ray, gamma ray, sound wave, ultrasonic wave, and infrasound wave.

[0042] In order to further explain the preparation method in the embodiments of the present invention, the following specific embodiments are proposed.

[0043] In a first embodiment, a composite material coated with graphite on the surface of a manganese oxide powder is prepared. The mass ratio of manganese oxide to graphite is: ι:χ, χ=ο.οι. The specific steps of preparation are:

(1) 10000 g of manganese oxide powder, 250 g of glucose and 5 L of water were uniformly mixed using a reaction vessel to obtain a mixture.

[0045] (2) The stirring power of the reaction vessel was set to 5 kW / m 3 and stirred, the temperature was set to 50 ° C;

[0046] (3) under a nitrogen atmosphere, the above mixture was placed in an electric resistance furnace, the temperature was raised to 300 ° C, while maintaining the furnace gas pressure of 2 MPa; and the ultrasonic wave, the constant temperature of 5 hours, A powder material is obtained.

[0047] (4) The powder material is ground, iron-removed, and sieved to obtain a powder material coated with graphite on the surface of the manganese oxide powder.

[0048] In the second embodiment, a composite material coated with graphite on the surface of the manganese oxide powder is prepared. The mass ratio of manganese oxide to graphite is: ι:χ, χ=ι. The specific steps of preparation are:

(1) 1000 g of manganese trioxide powder, 2380 g of sucrose, and 10 L of water were uniformly mixed using a reaction vessel to obtain a mixture.

[0050] (2) The stirring power of the reaction vessel was set to 80 kW / m 3 and stirred, the temperature was set to 85 ° C;

[0051] (3) placing the above mixture in an electric resistance furnace under an argon atmosphere, raising the temperature to 500 ° C, while maintaining The pressure in the furnace is 15 MPa; and the α-ray is activated, and the temperature is kept for 20 hours to obtain a powder material.

[0052] (4) The powder material is ground, iron-removed, and sieved to obtain a powder material in which graphite is coated on the surface of the manganese oxide.

[0053] In a third embodiment, a composite material coated with graphite on the surface of the manganese oxide powder is prepared. The mass ratio of manganese oxide to graphite is 1:X, X=0.5. The specific steps of preparation are:

(1) Using a reaction vessel, 5000 g of dimanganese trioxide powder, 6250 g of maltose, and 20 L of water were uniformly mixed to obtain a mixture.

[0055] (2) The stirring power of the reaction vessel was set to 45 kW / m 3 and stirred, the temperature was set to 68 ° C;

[0056] (3) In an oxygen-free atmosphere, the above mixture was placed in an electric resistance furnace, the temperature was raised to 450 ° C, while the pressure in the furnace was maintained at 8 MPa; and the ultrasonic wave was started, and the temperature was kept for 13 hours. , get the powder material.

[0057] (4) The powder material is ground, iron-removed, and sieved to obtain a powder material coated with graphite on the surface of the manganese oxide.

[0058] In summary, the composite material of the manganese oxide surface coated with graphite provided in the embodiment of the present invention and the preparation method thereof are coated with graphite on the surface of the manganese oxide, and the conductivity and hydrophobicity of the graphite are utilized to improve The catalytic effect of the composite material and the conductivity of the composite material; the use of electromagnetic waves and the heating method can not only accelerate the formation process of the composite material, but also avoid the high temperature decomposition of manganese oxide, and the electromagnetic wave can also activate the surface of the powder particle. To avoid agglomeration of the powder material; heat treatment of manganese oxide in an oxygen-free atmosphere can distort the internal lattice of the manganese oxide, form holes of oxygen atoms and improve the conductivity of the manganese oxide, and shorten the electron transfer in the redox reaction. Path, reduce internal resistance; Manganese oxide powder particles are coated with a plurality of graphite crystallites to form a plurality of catalytic active sites; most of the manganese oxide powder is rolled into a piece, and a catalytic active network is formed inside, thereby improving catalysis Efficiency; the surface of manganese oxide is coated with a protective layer of graphite, so it is difficult to produce side reactions. MnOOH ensures the stability of manganese oxide; graphite hydrophobicity is favorable to form a gas-liquid-solid three-phase interface, which is beneficial to three-phase catalysis of solid-liquid gas.

[0059]

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the present specification and the drawings are directly or indirectly Other related technical fields are equally included in the scope of patent protection of the present invention.

Claims

Claim

[Claim 1] A composite material coated with graphite on a surface of a manganese oxide, characterized in that a surface of a manganese oxide is coated with a graphite layer, and a mass ratio of the manganese oxide to graphite is 1: X, wherein 0.01 ≤ X ≤ 1 =

[Claim 2] The composite material according to claim 1, wherein the manganese oxide comprises Mn

0, one or more of Mn0 ₂ , Mn ₂ 0 ₃ , Mn ₃ 0 ₄ , Mn ₂ 0 ₅ , MnO ₃ and Mn ₂ 0 ₇ .

[Claim 3] The composite material according to claim 1, further comprising a metal compound coated on the surface of the manganese oxide.

[Claim 4] A method of preparing the composite material according to any of claims 1-3, comprising the steps of:

In the vessel, the manganese oxide powder, the carbon source and the water are uniformly mixed to obtain a mixture; under an anaerobic condition, the air pressure is maintained at 2-15 MPa, and the temperature is maintained at a constant temperature of 300 ° C to 500 ° C, and the mixture is heated and used. Electromagnetic wave irradiation, constant temperature 5-20 hours, to obtain a composite powder.

[Claim 5] The method according to claim 4, further comprising: grinding, removing iron, and sieving the obtained composite powder.

[Claim 6] The method according to claim 4, wherein the step of uniformly mixing the manganese oxide powder, the carbon source and the water in the container to obtain the mixture further comprises:

The stirring power of the vessel was set to 5-80 kW/m 3 and the temperature was set to 50-85 °C.

[Clave 7] The method according to claim 4, wherein the carbon source is an organic substance.

[Claim 8] The method according to claim 7, wherein the carbon source comprises one or more of glucose, maltose, sucrose, lactose, and starch.

[Claim 9] The method according to claim 4, wherein the anaerobic condition is nitrogen or an inert gas atmosphere.

[Claim 10] The method according to claim 4, wherein the electromagnetic wave comprises microwave, medium wave, long wave, short wave, laser, infrared, ultraviolet, visible light, alpha ray, beta ray, gamma ray, sound wave One or more of ultrasonic waves and infrasound waves.