阅读说明：本技术 一种利用黏土矿物制备碳化硅纳米材料、含碳化硅纳米复合材料的方法及应用 (Method for preparing silicon carbide nano material and silicon carbide-containing nano composite material by using clay mineral and application ) 是由 朱润良 陈情泽 杜静 何宏平 朱建喜 何秋芝 杨奕煊 魏洪燕 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种利用黏土矿物制备碳化硅纳米材料、含碳化硅纳米复合材料的方法及应用。该方法包括：将黏土矿物-碳复合物在还原剂的作用下发生还原反应,制得所述碳化硅纳米材料、含碳化硅纳米复合材料。本发明制备的碳化硅纳米材料、含碳化硅纳米复合材料具有大比表面积和多级孔结构,通过调节有机前驱体中碳的含量能得到碳化硅纳米材料和含有碳化硅的纳米复合材料。此外,改变有机黏土矿物类型可调控碳化硅纳米材料和含碳化硅纳米复合材料的形貌。该方法所用原料丰富,价格低廉,制备过程简单可控,易于大规模制备；产物的成分可调,形貌可控,可满足多种应用需求。(The invention discloses a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by using clay minerals and application thereof. The method comprises the following steps: and performing reduction reaction on the clay mineral-carbon composite under the action of a reducing agent to prepare the silicon carbide nano material and the silicon carbide-containing nano composite material. The silicon carbide nano material and the silicon carbide-containing nano composite material prepared by the invention have large specific surface area and a multi-level pore structure, and the silicon carbide nano material and the silicon carbide-containing nano composite material can be obtained by adjusting the carbon content in the organic precursor. In addition, the change of the type of the organic clay mineral can regulate and control the shapes of the silicon carbide nano material and the silicon carbide-containing nano composite material. The method has the advantages of abundant raw materials, low cost, simple and controllable preparation process, and easy large-scale preparation; the product has adjustable components and controllable appearance, and can meet various application requirements.)

1. The method for preparing the silicon carbide nano material and the silicon carbide-containing nano composite material by utilizing the clay mineral is characterized by comprising the following steps of: and performing reduction reaction on the clay mineral-carbon composite under the action of a reducing agent to prepare the silicon carbide nano material and the silicon carbide-containing nano composite material.

2. The method of claim 1, wherein the reduction reaction is performed in a closed oxygen-free environment,

preferably, the temperature of the reduction reaction is 550-1000 ℃, and the heat preservation time is 3-20 h.

3. The method of claim 1, wherein the reducing agent is a metal powder;

preferably, the metal includes at least one of magnesium, aluminum, zinc, sodium, potassium, and calcium.

4. The method of claim 1, further comprising mixing the clay mineral-carbon complex, the reducing agent and the metal inorganic salt uniformly before the reduction reaction,

preferably, the metal inorganic salt includes at least one of sodium chloride, potassium chloride, lithium chloride and calcium chloride;

more preferably, the mass ratio of the clay mineral-carbon composite to the metal inorganic salt is 1: 4-40.

5. The method according to claim 1, wherein the clay mineral-carbon composite is prepared by: under the protection of inert gas, carrying out high-temperature carbonization reduction reaction on the organic clay mineral to prepare the clay mineral-carbon composite.

6. The method as claimed in claim 5, wherein the temperature of the high temperature carbonization-reduction reaction is 500-1000 ℃ and the time is 0.5-24 h;

preferably, the high-temperature carbonization reduction reaction is carried out under the protection of argon.

7. The method according to claim 5, wherein the organo clay mineral is obtained by compounding organic substances and clay mineral substances through an ion exchange reaction or a melt polymerization manner;

preferably, the mass ratio of the clay mineral substances to the organic matters is 1: 0.1-5.

8. The method of claim 7, wherein the clay mineral species comprises at least one of a clay mineral and a modification product of a clay mineral;

preferably, the clay mineral comprises at least one of montmorillonite, vermiculite, biotite, muscovite, illite, sepiolite, palygorskite, kaolinite and halloysite;

preferably, the clay mineral modification product comprises a modification treatment product obtained by subjecting the clay mineral to at least one of heat treatment, acid treatment, organic modification and inorganic modification;

preferably, the organic matter comprises at least one of cationic organic matter containing benzene ring and non-ionic organic matter;

more preferably, the cationic organic compound containing benzene ring comprises at least one of methylene blue, rhodamine B and gentian violet; the non-ionic organic substance includes at least one of glucose and acrylonitrile.

9. The method of claim 1, comprising: adjusting the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite to prepare a silicon carbide nano material or a silicon carbide-containing nano composite material;

preferably, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted by adjusting the mass ratio of the clay mineral to the organic matter in the clay mineral;

more preferably, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted to be 1: 0.1-0.3, preparing the silicon carbide nano material;

preferably, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted to be less than 1: 0.3 or more than 1:0.1, and preparing the silicon carbide-containing nano composite material.

10. Use of the silicon carbide nanomaterial and silicon carbide-containing nanocomposite prepared according to the method of any one of claims 1 to 9 in the field of catalyst supports, microwave absorption or composites.

Technical Field

The invention relates to the technical field of inorganic nano materials, in particular to a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by using clay minerals and application of the silicon carbide-containing nano composite material.

Background

The nano silicon carbide has larger specific surface area, wide band gap, excellent thermal conductivity and corrosion resistance, and is widely applied to various fields, such as catalyst carriers, luminescent materials, wave-absorbing materials and the like. The traditional preparation method of the nano silicon carbide mainly comprises a chemical vapor deposition method, a shape memory synthesis method and an arc discharge method. For example, Meng and coworkers are SiCl in the gas phase₄And CCl₄One-dimensional nano silicon carbide materials (Meng et al, Crystal. growth.2000,209:801-806) were prepared as silicon source and carbon source. The Ledoux project group prepared high surface area silicon carbide porous materials using SiO vapor and activated carbon at 1010-. Seeger and its combinationThe authors used a mixture of silicon and graphite as the starting material, a graphite plate as the electrode, and the mixture of silicon and graphite was excited by the transfer of electrons from the anode and evaporated on the cathode under a helium atmosphere of 53Kpa at a voltage of 220V and a current of 40A to form nanowhiskers (Seeger al., adv. Mater.2000,12(4): 279-) -282).

However, these methods have some disadvantages, such as the use of toxic reagents, high equipment requirements, insufficient contact of raw materials, low reaction yield, high cost, time consumption, etc., and are difficult to realize in large-scale production. Therefore, it is necessary to find a new method for preparing nano silicon carbide, which is economical, efficient and simple.

In view of this, the invention is particularly proposed.

Disclosure of Invention

The present invention aims at overcoming the demerits of available technology, and provides process of preparing nanometer silicon carbide material and nanometer composite silicon carbide material with clay mineral and its application.

The invention is realized by the following steps:

in a first aspect, an embodiment of the present invention provides a method for preparing a silicon carbide nanomaterial and a silicon carbide-containing nanocomposite material from clay minerals, including: the clay mineral-carbon composite is subjected to a reduction reaction under the action of a reducing agent to prepare a silicon carbide nano material and a silicon carbide-containing nano composite material.

The inventor has long practiced and proposed a method for preparing silicon carbide nano-material and silicon carbide-containing nano-composite material by using clay mineral, which comprises the following steps: the clay mineral-carbon composite is subjected to a reduction reaction under the action of a reducing agent to prepare a silicon carbide nano material and a silicon carbide-containing nano composite material. In the reduction reaction process, the reducing agent firstly reduces silicon-oxygen tetrahedron in the clay mineral-carbon composite into silicon nano-crystals, then the high-activity silicon nano-crystals are combined with carbon particles in the clay mineral-carbon composite to generate the silicon carbide nano-material, and meanwhile, if the silicon nano-crystals and/or the carbon nano-particles which are not combined in the reduction reaction process exist, the silicon nano-crystals and/or the carbon nano-particles can be combined with the silicon carbide nano-material to generate the silicon carbide-containing nano-composite material. The whole reaction effectively avoids the problems of poor contact with silicon, uneven distribution and the like caused by an additional carbon material through the in-situ reaction of carbon atoms and silicon atoms in the clay mineral-carbon compound, simplifies the traditional preparation process, and obtains the silicon carbide material with large specific surface area and a hierarchical pore structure.

The method provided by the embodiment of the invention overcomes the defects in the existing preparation process of the silicon carbide nano material that independent silicon source and carbon source are used as raw materials, and the silicon source or the carbon source with a specific shape (such as sheet shape, tubular shape and the like) is required to be used as a precursor to effectively regulate and control the shape of the silicon carbide, but the silicon source with a certain shape and the carbon source with a certain shape are mixed, so that the uniform dispersion of the silicon and carbon atom layers is difficult to realize, the reaction is uneven, the structure and the shape of the finally obtained product are difficult to control, the raw materials are expensive, the preparation is complex and the like. According to the method provided by the invention, the clay minerals are used as precursors, the organic clay minerals have a template effect on the synthetic silicon carbide material, and the silicon carbide nano materials and the silicon carbide-containing nano composite materials with different morphologies are obtained by using different types of clay minerals. The method has the advantages of rich raw materials, low price and simple and controllable preparation process, and provides a new method for preparing the silicon carbide nano material and the silicon carbide-containing nano composite material and a new thought for efficiently utilizing clay mineral resources with high value.

In an alternative embodiment, the reduction reaction is carried out in a closed oxygen-free environment;

preferably, the temperature of the reduction reaction is 550-.

The embodiment of the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by utilizing clay minerals, wherein a reduction reaction is carried out in a closed oxygen-free environment to prevent raw materials from being oxidized, meanwhile, the reaction is carried out at the temperature of 550-plus 1000 ℃, if the temperature is too low, silicon carbide materials (such as the silicon carbide nano material and the silicon carbide-containing nano composite material) cannot be obtained, and if the reaction temperature is higher than the temperature, other impurity phases can be generated to reduce the purity of the silicon carbide materials.

In an alternative embodiment, the reducing agent is a metal powder;

preferably, the metal includes at least one of magnesium, aluminum, zinc, sodium, potassium, and calcium.

In an optional embodiment, the method further comprises the steps of uniformly mixing the clay mineral-carbon composite, the reducing agent and the metal inorganic salt before the reduction reaction;

preferably, the metal inorganic salt includes at least one of sodium chloride, potassium chloride, lithium chloride and calcium chloride;

more preferably, the mass ratio of the clay mineral-carbon composite to the metal inorganic salt is 1: 4-40.

The embodiment of the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by using clay minerals, which further comprises the following steps: the clay mineral-carbon composite, the reducing agent and the metal inorganic salt are uniformly mixed, on one hand, the metal inorganic salt absorbs excessive heat released in the thermal reduction reaction of the metal powder of the reducing agent and prevents the over-high temperature of the system, so that the generation of high-temperature phases (such as mullite, cordierite and the like) is inhibited, and on the other hand, the metal inorganic salt serves as a separant and prevents generated silicon carbide materials (such as silicon carbide nano materials and silicon carbide-containing nano composite materials) from aggregating and combining into bulk crystals.

In an alternative embodiment, the clay mineral-carbon composite is prepared by the following method: under the protection of inert gas, the organic clay mineral is subjected to high-temperature carbonization reduction reaction to prepare the clay mineral-carbon composite.

The embodiment of the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by utilizing clay minerals, wherein the clay mineral-carbon composite is prepared by carrying out high-temperature carbonization reduction reaction on organic clay minerals. In the process of air-isolated carbonization, organic matters in the organic clay are converted into carbon materials which are uniformly dispersed in clay minerals, and carbon and silicon are contacted on an atom level, so that the generation of silicon carbide in subsequent reactions is facilitated.

In an alternative embodiment, the organic clay mineral is obtained by compounding organic matters and clay mineral substances through an ion exchange reaction or a melt polymerization manner;

preferably, the mass ratio of the clay mineral substances to the organic substances in the organic clay mineral is 1: 0.1-5.

In an optional embodiment, the temperature of the high-temperature carbonization-reduction reaction is 500-;

preferably, the high-temperature carbonization reduction reaction is carried out under the protection of argon.

The embodiment of the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by utilizing clay minerals, wherein the temperature of high-temperature carbonization reduction reaction is controlled to be 500-; if the reaction temperature is high, high-temperature phases (such as mullite and olivine) are generated, impurities which are difficult to remove are contained in the reaction end product, the reaction time is prolonged, and energy is wasted.

In an alternative embodiment, the clay mineral species comprises at least one of a clay mineral and a modified product of a clay mineral;

preferably, the clay mineral includes at least one of montmorillonite, vermiculite, biotite, muscovite, illite, sepiolite, palygorskite, kaolinite, and halloysite;

preferably, the clay mineral modification product includes a clay mineral modification treatment product obtained by subjecting the clay mineral to at least one of heat treatment, acid treatment, organic modification and inorganic modification.

In an alternative embodiment, the organic substance includes at least one of a cationic organic substance containing a benzene ring and a non-ionic organic substance;

preferably, the cationic organic matter containing benzene ring comprises at least one of methylene blue, rhodamine B and gentian violet;

preferably, the non-ionic organic substance includes at least one of glucose and acrylonitrile.

The embodiment of the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by utilizing clay minerals, wherein the high-temperature carbonization reduction reaction takes a clay mineral-carbon composite as a reaction raw material, the clay mineral-carbon composite is prepared by carrying out high-temperature carbonization reduction reaction on organic clay minerals, and the reason for carrying out the high-temperature carbonization reduction reaction takes the organic clay minerals loaded with organic matters as precursors is as follows: on one hand, the organic clay minerals have a template effect on the synthetic silicon carbide material, and the silicon carbide materials with different morphologies are obtained by using different types of clay minerals; on the other hand, by simply regulating and controlling the content of the organic matters in the precursor, silicon carbide-containing nanocomposites (such as at least one of carbon-silicon carbide nanocomposites, silicon-silicon carbide nanocomposites and carbon-silicon carbide nanocomposites) with different proportions can be obtained. Further, if the precursor is an organic substance containing heteroatoms such as N, P, S, the silicon carbide nano composite material doped with hetero atoms (such as N, P, S) can be obtained to meet various application requirements; more importantly, in the process of air-isolated carbonization, the organic matters are converted into the carbon material in situ, so that the problems of poor contact with silicon, uneven distribution and the like caused by the addition of the carbon material are effectively solved, the organic matters in the precursor organic clay mineral are converted into the carbon material uniformly dispersed in the clay mineral, and the carbon and the silicon are contacted on an atom level, so that the generation of the silicon carbide material in the subsequent reaction is facilitated.

In an alternative embodiment, the method comprises the following steps: adjusting the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite to prepare the silicon carbide nano material or the silicon carbide-containing nano composite material;

preferably, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted by adjusting the mass ratio of the clay mineral to the organic matter in the organic clay mineral;

more preferably, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted to be 1: 0.1-0.3, preparing the silicon carbide nano material;

preferably, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted to be less than 1: 0.3 or more than 1:0.1, and preparing the silicon carbide-containing nano composite material.

The embodiment of the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by utilizing clay minerals, which takes organic clay minerals loaded with organic matters as precursors, adjusts the mass ratio of the clay minerals and carbon in a clay mineral-carbon composite by adjusting the mass ratio of the clay minerals and the organic matters in the organic clay minerals, and can adjust and control the mass ratio of the clay minerals and the carbon in the clay mineral-carbon composite to adjust and control the composition of products.

As a preferred embodiment in the embodiment of the present invention, the mass ratio of the clay mineral to the carbon in the clay mineral-carbon composite is adjusted to 1: 0.1-0.3, the silicon carbide nano material is prepared, because in the proportion range, silicon-oxygen tetrahedron in the clay mineral-carbon composite is reduced into silicon nano crystal, and the high-activity silicon nano crystal is combined with carbon in the clay mineral-carbon composite to generate the silicon carbide nano material.

As another preferred embodiment in the embodiment of the present invention, the mass ratio of the clay mineral and the carbon in the clay mineral-carbon composite is adjusted to be less than 1: 0.3 or more than 1:0.1, and preparing to obtain the silicon carbide-containing nanocomposite material, wherein the silicon carbide-containing nanocomposite material comprises: at least one of a composite material containing silicon carbide and silicon, a composite material containing silicon carbide and carbon, and a composite material containing silicon carbide and silicon and carbon. This is because when the mass ratio of clay mineral and carbon in the clay mineral-carbon composite is less than 1: 0.3 or more than 1:0.1, reducing silicon-oxygen tetrahedron in the clay mineral-carbon composite into silicon nano-crystals, wherein the silicon nano-crystals can not be completely combined with carbon in the clay mineral-carbon composite to generate a silicon carbide nano-material, and the un-combined carbon nano-crystals or silicon nano-crystals are combined with the silicon carbide nano-material to form the silicon carbide-containing nano-composite material.

In an optional embodiment, further comprising post-processing: soaking in dilute acid for 5-10min, washing with ultrapure water to neutrality, centrifuging, and drying;

preferably, the dilute acid comprises any one of dilute hydrochloric acid and dilute hydrofluoric acid.

In a second aspect, the embodiment of the present invention further provides an application of the silicon carbide nanomaterial and the silicon carbide-containing nanocomposite material prepared by the above method in the fields of catalyst carriers, microwave absorption or composite materials.

The invention has the following beneficial effects:

the invention provides a method for preparing a silicon carbide nano material and a silicon carbide-containing nano composite material by using clay minerals and application thereof. According to the invention, the clay mineral-carbon composite is subjected to a reduction reaction under the action of a reducing agent to prepare the silicon carbide nano material and the silicon carbide-containing nano composite material. In the reduction reaction process, the reducing agent firstly reduces silicon-oxygen tetrahedron in the clay mineral-carbon composite into silicon nano-crystals, then the high-activity silicon nano-crystals are combined with carbon particles in the clay mineral-carbon composite to generate the silicon carbide nano-material, and meanwhile, if the silicon nano-crystals and/or the carbon nano-particles which are not combined in the reduction reaction process exist, the silicon nano-crystals and/or the carbon nano-particles can be combined with the silicon carbide nano-material to generate the silicon carbide-containing nano-composite material. The whole reaction effectively avoids the problems of poor contact with silicon, uneven distribution and the like caused by an additional carbon material through the in-situ reaction of carbon atoms and silicon atoms in the compound, so that the prepared product is expected to be applied to the fields of catalyst carriers, microwave absorption, composite materials and the like.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is an X-ray diffraction pattern of the product prepared in example 1;

FIG. 2 is a scanning electron microscope photograph of the product prepared in example 1;

FIG. 3 is a transmission electron microscope photograph of the product prepared in example 1;

FIG. 4 is a high resolution X-ray photoelectron spectrum of Si2p of the product prepared in example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The features and properties of the present invention are described in further detail below with reference to examples.