A carbon-silicon oxide nanocomposite material based on clay minerals and its preparation method and application

Abstract

The present invention relates to a carbon-silicon oxide nanocomposite material based on clay minerals and its preparation method and application, belonging to the technical field of inorganic nanomaterials. The method for preparing a carbon-silicon oxide nanocomposite material based on clay minerals provided by the present invention comprises the following steps: (1) carbonizing a carbon-containing clay mineral in an inert atmosphere to obtain a composite of carbon and clay minerals; (2) grinding the composite of carbon and clay minerals to obtain a ground product; (3) subjecting the ground product to acid treatment, followed by washing and drying to obtain a carbon-silicon oxide nanocomposite material. The prepared nanocomposite material has a large specific surface area, a multi-level pore structure, a hydrophobic surface, good adsorption properties, contains carbon and silicon elements, has high carbon-silicon interface stability, and has good ion / electron transmission performance. It has a wide range of application value in the fields of organic pollutant treatment and lithium-ion batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic nanomaterials, and in particular to a carbon-silicon oxide nanocomposite material based on clay minerals, and a preparation method and application thereof. Background Art

[0002] Carbon-silicon oxide nanocomposites possess a large specific surface area, corrosion resistance, and thermal stability, and are widely used in a variety of fields, including adsorption, catalysis, and microwave absorbing materials. Furthermore, carbon-silicon oxides, containing both silicon and carbon, exhibit excellent silicon-carbon interface stability, making them suitable precursors for silicon-carbon nanocomposites and, in turn, for applications in lithium-ion batteries.

[0003] Currently, methods for preparing carbon-silicon oxide nanocomposites include vapor deposition, magnesium thermal reduction, and mechanical alloying. However, these methods all have drawbacks, such as expensive raw materials, high costs, complex preparation processes, and long production cycles, which hinder the large-scale production and practical application of carbon-silicon oxide nanocomposites. Therefore, it is imperative to find a simple, low-cost, and efficient new method for preparing carbon-silicon oxide nanocomposites. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of existing technologies by providing a clay mineral-based carbon-silicon oxide nanocomposite material, its preparation method, and its application. The present invention utilizes a simple preparation method and readily available raw materials. The resulting carbon-silicon oxide nanocomposite material exhibits a hierarchical pore structure, a hydrophobic surface, and excellent interfacial stability. The material has high application value in pollutant remediation and lithium batteries.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a method for preparing a carbon-silicon oxide nanocomposite material based on clay minerals, comprising the following steps:

[0007] (1) carbonizing a carbonaceous clay mineral in an inert atmosphere to obtain a clay mineral composite; the carbonaceous clay mineral is a natural carbonaceous clay mineral or a clay mineral modified by organic matter; the natural carbonaceous clay mineral includes black talc;

[0008] (2) grinding the clay mineral composite obtained in step (1) to obtain a ground product; the grinding method is ball milling;

[0009] (3) treating the ground product obtained in step (2) with acid, washing it, and drying it to obtain a carbon-silicon oxide nanocomposite material; during the acid treatment, the volume concentration of the acid in the acid solution is 5-20%.

[0010] Clay minerals are abundant mineral resources in my country. They possess a natural nanostructure, a large theoretical specific surface area, and adsorb a large amount of exchangeable cations, making them commonly used as adsorbents for organic pollutants. This method uses carbonaceous clay minerals as raw materials to prepare carbon-silicon oxide nanocomposites. This method can fully utilize the natural carbonaceous clay mineral black talc, as well as organically modified clay minerals obtained by processing natural carbonaceous or carbon-free clay minerals, or discarded clay minerals after adsorbing organic pollutants, thereby realizing the resource utilization of clay minerals and discarded clay minerals.

[0011] By carbonizing the above-mentioned carbon-containing clay minerals in an inert atmosphere, the carbon-containing components therein can be converted into stable carbon sheets, which together with the clay mineral components form a composite of carbon and clay minerals. By ball milling, the shear force of the ball milling can peel off the carbon sheets and clay minerals, increasing the specific surface area of ​​the clay minerals and allowing the acid solution of the subsequent acid treatment to fully contact the clay minerals; at the same time, the impact force of the ball milling can refine the clay mineral sheets and make their particle size reach hundreds of nanometers. Compared with other grinding methods, more surfaces and end faces can be exposed, which is also conducive to acid treatment. If grinding is not performed, the Al in the clay minerals will 3+ The cations cannot be fully dissolved, the carbon-silicon oxide nanocomposite structure cannot be completely formed, and the material adsorption performance is poor.

[0012] Finally, the ground product undergoes acid treatment: using at least one of hydrochloric acid, sulfuric acid, and nitric acid within the concentration range of the aforementioned acid solutions, the cations in the clay mineral's octahedral sheets are dissolved, forming a porous nano-silicon dioxide structure. The carbon sheets, however, are retained due to their excellent acid resistance. After washing and drying, a carbon-silicon oxide nanocomposite material is formed. If the acid concentration is too low, the cations in the octahedral sheets are difficult to dissolve, and a porous structure with a large specific surface area cannot be obtained. If ball milling, acid treatment, and carbonization are performed first, the carbon-containing components in the carbonaceous clay mineral are lost, and the carbon-silicon oxide nanocomposite material cannot be obtained.

[0013] The above method realizes the resource utilization of clay minerals and can prepare nano-composite materials with large specific surface area, corrosion resistance and good thermal stability. The nano-composite materials are mainly composed of carbon-silicon oxide: they have a multi-level pore structure of micropores and mesopores, a large specific surface area, and good adsorption properties, and can also be used as a carrier to load active components; because they contain both silicon and carbon elements, they also have good silicon-carbon interface stability, and can be used as a precursor of silicon-carbon nano-composite materials, with wide application value.

[0014] Preferably, in step (1), the carbonization temperature is 500-800°C and the carbonization time is 2-5 hours. In an inert atmosphere, at this carbonization temperature and time, the natural organic matter or adsorbed organic matter in the carbonaceous clay mineral can be fully carbonized and converted into carbon sheets with good acid resistance, which serve as the carbon source for the nanocomposite material. If the carbonization is insufficient, the carbon sheets cannot be formed.

[0015] Preferably, in step (1), the organic matter in the organic-modified clay mineral includes an organic dye and an organic surfactant. The organic dye and organic surfactant include dyes such as crystal violet, methylene blue, and malachite blue, and surfactants such as hexadecyltrimethylammonium bromide and hexadecyltrimethoxysilane, all of which are common types of organic pollutants. The raw materials for the preparation of the present invention can be obtained by recycling waste clay minerals that have adsorbed the organic pollutants, or by directly introducing the organic matter into the clay mineral.

[0016] Preferably, in step (1), in the clay mineral modified by organic matter, the mass ratio of clay mineral to organic matter is 1: (0.05-2). Adjustment of this ratio can change the carbon-silicon ratio in the nanocomposite material, making it suitable for different application scenarios. If the proportion of organic matter is high, the carbon content in the carbon-silicon oxide nanocomposite material will increase, which is beneficial for its application in lithium-ion batteries. However, if the proportion of organic matter is too low, the carbon content will be low, which is not conducive to broadening its application; if the proportion of organic matter is too high, it may exceed the adsorption range of clay minerals. Furthermore, if the organic precursor is selected from organic matter containing heteroatoms such as N, S, and P, a carbon-silicon oxide nanocomposite material doped with heteroatoms (such as N, S, and P) can be obtained, which can meet different application requirements.

[0017] Further preferably, in the step (1), the clay mineral modified by organic matter includes at least one of montmorillonite, palygorskite, kaolinite, sepiolite, talc, black talc, illite, saponite, serpentine, chlorite, nickel talc, nickel saponite, zinc saponite, iron saponite, nickel serpentine, manganese chlorite, and nickel chlorite. The clay mineral is a hydrous silicate mineral containing aluminum and magnesium, which can provide a silicon oxide source for the nanocomposite material. The clay mineral modified by organic matter in step (1) can be obtained by directly introducing organic matter (carbon source) into carbon-containing or carbon-free clay minerals for modification, or can be obtained by further treating clay minerals (carbon-containing or carbon-free) that have been acid-treated, heat-treated, organically modified, or mechanically treated with organic matter.

[0018] Preferably, in step (2), the ball-to-material ratio of the ball milling is (10-60):1. At this ball-to-material ratio, the clay mineral can expose a larger surface area. If the ball-to-material ratio is too small, the carbon sheet cannot be fully separated from the clay mineral, and the subsequent acid treatment cannot fully dissolve the cations, affecting the preparation effect; if the ball-to-material ratio is too large, the material loss is large. Preferably, the grinding ball is made of one of agate, stainless steel, zirconia, and corundum.

[0019] Further preferably, in step (2), the ball milling speed is 100-700 rpm and the ball milling time is 2-20 hours. At a ball-to-material ratio of (10-60):1, the ball milling speed and time can ensure that the clay minerals are fully separated from the carbon sheets, and refine the clay minerals and increase their specific surface area, facilitating efficient subsequent acid treatment.

[0020] Preferably, in step (3), the acid treatment temperature is 60-90°C and the acid treatment time is 1-24h. Under such conditions, the strong acid solution can partially or completely dissolve the Al in the octahedral sheets of the clay mineral silicate layered structure. 3+ Mg 2+ The remaining silicon-oxygen tetrahedral sheets are stacked on the surface and end faces, and between the end faces to form a large number of pore structures, thereby obtaining porous silicon oxide, while retaining the acid-resistant carbon sheet to form a carbon-silicon oxide nanocomposite material.

[0021] Furthermore, by regulating the volume concentration of the acid and the acid treatment time within a certain range, the content of the metal oxide in the nanocomposite material can be controlled to obtain a carbon-silicon oxide nanocomposite material containing or without metal oxides:

[0022] Preferably, under the above acid treatment conditions, when the volume concentration of the acid is greater than 10% and less than or equal to 20%, the Al in the octahedral sheets of the clay mineral can be fully dissolved. 3+ Mg 2+ The carbon-silicon oxide nanocomposite material without metal oxides is prepared by dissolving the octahedral cations thoroughly, which is conducive to the formation of the mesoporous structure of the silicon oxide and has a good adsorption effect.

[0023] Further preferably, in step (3), the acid treatment temperature is 60-90° C., the acid treatment time is 1-4 hours, and the volume concentration of the acid in the acid solution is 5-10%, thereby preparing a carbon-silicon oxide nanocomposite material containing metal oxides. When the volume concentration of the acid is adjusted to 5-10% and the acid treatment time is 1-4 hours, the cations in the clay mineral octahedral sheets are not completely dissolved, and the prepared carbon-silicon oxide nanocomposite material contains a small amount of metal oxide (such as at least one of Al2O3, MgO, Fe2O3, NiO, Ti2O, and CuO). The reducible metal oxide can regulate the electronic state and catalytic activity of the metal nanoparticles, which is beneficial to improving the catalytic performance and selectivity of the target product.

[0024] In the second aspect, the present invention provides a carbon-silicon oxide nanocomposite material prepared by the above-mentioned method for preparing a carbon-silicon oxide nanocomposite material based on clay minerals. The carbon-silicon oxide nanocomposite material provided by the present invention has a large specific surface area, which can reach up to 446m 2 / g, and has a multi-level porous structure of micropores and mesopores. At the same time, the surface is hydrophobic, and the carbon-silicon interface is highly stable. It has good adsorption properties and ion / electron transport properties, and has broad application potential.

[0025] In a third aspect, the present invention provides the application of the above-mentioned carbon-silicon oxide nanocomposite material in the treatment of organic pollutants and lithium-ion batteries. Preferably, it can be used as an adsorbent or catalyst carrier for volatile organic pollutants. The carbon-silicon oxide nanocomposite material provided by the present invention shows good performance in the field of organic matter treatment, and can be used as a volatile pollutant adsorption material, or as a carrier to load active components and be used as a catalyst; at the same time, it can be used as a raw material for the preparation of silicon-carbon nanocomposite materials, which are precursors of lithium battery negative electrode materials, and used in the preparation of lithium-ion battery negative electrode materials. It has fast ion / electron transmission and low tap density, and the assembled battery shows good electrochemical lithium storage performance.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention can prepare carbon-silicon oxide nanocomposites using natural carbon-containing clay minerals or discarded organically modified clay minerals as raw materials. The preparation method is simple, environmentally friendly, and easily scalable, meeting various application needs while also providing a new method for resource utilization of clay minerals. The resulting carbon-silicon oxide nanocomposites have a large specific surface area, a multi-level pore structure, and a hydrophobic surface, exhibiting excellent adsorption properties. They also contain carbon and silicon elements, resulting in a highly stable carbon-silicon interface and excellent ion / electron transport properties, making them widely applicable in the treatment of organic pollutants and lithium-ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is an X-ray diffraction pattern of a carbon-silicon oxide nanocomposite material without metal oxide;

[0029] Figure 2 is the pore size distribution diagram of carbon-silicon oxide nanocomposite without metal oxide;

[0030] Figure 3 is a nitrogen adsorption-desorption curve of a carbon-silicon oxide nanocomposite material without metal oxide;

[0031] Figure 4 is the SEM-EDS image of carbon-silicon oxide nanocomposite containing metal oxide;

[0032] Figure 5 is the breakthrough curve of benzene adsorption on carbon-silicon oxide nanocomposites without metal oxides;

[0033] Figure 6 A diagram showing the catalytic degradation of toluene by a platinum-carbon-silicon oxide catalyst prepared from a carbon-silicon oxide nanocomposite material free of metal oxides;

[0034] Figure 7 The effect of three-cycle catalytic degradation of toluene by platinum-carbon-silicon oxide catalyst prepared from carbon-silicon oxide nanocomposites containing metal oxides;

[0035] Figure 8 This is the X-ray diffraction pattern of the composite product of Comparative Example 1. DETAILED DESCRIPTION

[0036] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below with reference to specific examples. The experimental methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used are commercially available unless otherwise specified.

[0037] Example 1

[0038] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention, wherein the preparation method of the carbon-silicon oxide nanocomposite material of this embodiment comprises the following steps:

[0039] (1) Dry montmorillonite adsorbed with crystal violet dye was placed in a tube furnace (mass ratio of clay mineral to organic matter was 1:0.05) and carbonized at 700°C in a flowing nitrogen stream for 3 h to obtain a carbon / montmorillonite composite.

[0040] (2) The carbon / montmorillonite composite was added to a ball mill containing grinding balls to a ball-to-material ratio of 10:1, and ball milled at 700 rpm for 10 h to obtain a ball-milled product;

[0041] (3) The ball-milled product was placed in 20% by volume hydrochloric acid, heated in a water bath at 80° C. for 1 h, then washed with ultrapure water until neutral, centrifuged, and dried to obtain a carbon-silicon oxide nanocomposite material free of metal oxides.

[0042] The obtained nanocomposite materials were analyzed by X-ray diffraction spectroscopy (XRD). Figure 1 It can be seen that, in addition to the characteristic peak of quartz, there is only a peak around 22.5°, which is caused by the presence of amorphous silica.

[0043] The pore size distribution of the obtained nanocomposite material is shown in Figure 2 The pore size is mainly distributed in the micropore and mesopore levels, and the material has a multi-level pore structure with both micropores and mesopores. In summary, it can be seen that a carbon-silicon oxide nanocomposite material without metal oxides has been successfully prepared.

[0044] The nitrogen adsorption-desorption curves of the obtained nanocomposite materials are shown in Figure 2. Figure 3 The curve of the obtained nanocomposite material belongs to type IV isotherm with H3 hysteresis loop, which further illustrates that the carbon-silicon oxide nanocomposite material contains mesopores; the rapid increase of nitrogen adsorption in the low-pressure zone indicates that the material contains a large number of micropores.

[0045] The specific surface area of ​​the material was calculated based on BET and is 410 m 2 / g, with a large specific surface area and good adsorption performance.

[0046] Example 2

[0047] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention, wherein the preparation method of the carbon-silicon oxide nanocomposite material of this embodiment comprises the following steps:

[0048] (1) Dry palygorskite adsorbed with methylene blue dye was placed in a tube furnace (mass ratio of clay minerals to organic matter was 1:0.1) and carbonized at 800°C in a flowing nitrogen stream for 2 h to obtain a carbon / palygorskite composite.

[0049] (2) adding the carbon / palygorskite composite to a ball mill containing grinding balls to a ball-to-material ratio of 20:1, and ball milling at 400 rpm for 8 h to obtain a ball-milled product;

[0050] (3) The ball-milled product was placed in 10% by volume hydrochloric acid, heated in a water bath at 80° C. for 1 h, then washed with ultrapure water until neutral, centrifuged, and dried to obtain a carbon-silicon oxide nanocomposite material containing metal oxides.

[0051] The obtained nanocomposite materials were analyzed by SEM-EDS. Figure 4 It can be seen that in addition to carbon, silicon, and oxygen, there are also small amounts of aluminum, magnesium, and iron. Carbon-silicon oxide nanocomposites containing metal oxides have been successfully prepared.

[0052] The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite material was calculated by BET method to be 390 m 2 / g, with a large specific surface area and good adsorption performance.

[0053] Example 3

[0054] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention, wherein the preparation method of the carbon-silicon oxide nanocomposite material of this embodiment comprises the following steps:

[0055] (1) Dry montmorillonite adsorbed with crystal violet dye was placed in a tube furnace (mass ratio of clay minerals to organic matter was 1:0.5) and carbonized at 700°C in a flowing nitrogen stream for 3 h to obtain a carbon / montmorillonite composite.

[0056] (2) The carbon / montmorillonite composite was added to a ball mill containing grinding balls to a ball-to-material ratio of 20:1, and ball milled at 500 rpm for 10 h to obtain a ball-milled product;

[0057] (3) The ball-milled product was placed in 7.3% hydrochloric acid, heated in a water bath at 80°C for 4 h, then washed with ultrapure water until neutral, centrifuged, and dried to obtain a carbon-silicon oxide nanocomposite material containing metal oxides. The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite material was calculated by the BET method to be 446 m 2 / g, with a large specific surface area and good adsorption performance.

[0058] Example 4

[0059] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention, wherein the preparation method of the carbon-silicon oxide nanocomposite material of this embodiment comprises the following steps:

[0060] (1) Dry black talc was placed in a tube furnace and carbonized at 500°C in a flowing nitrogen stream for 5 h to obtain a carbon-talc composite;

[0061] (2) The carbon-talc composite was added to a ball mill containing grinding balls to a ball-to-material ratio of 60:1, and ball milled at 700 rpm for 2 h to obtain a ball-milled product;

[0062] (3) The ball-milled product was placed in 11% nitric acid by volume, heated in a water bath at 60° C. for 24 h, then washed with ultrapure water until neutral, centrifuged, and dried to obtain a carbon-silicon oxide nanocomposite material free of metal oxides.

[0063] The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite material was calculated by BET method to be 226 m 2 / g, with a large specific surface area and good adsorption performance.

[0064] Example 5

[0065] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention, wherein the preparation method of the carbon-silicon oxide nanocomposite material of this embodiment comprises the following steps:

[0066] (1) Dry nickel talc adsorbed with the surfactant cetyltrimethylammonium bromide was placed in a tube furnace (the mass ratio of clay minerals to organic matter was 1:2) and carbonized at 800°C in a flowing nitrogen stream for 2 h to obtain a carbon / nickel talc composite.

[0067] (2) The carbon / nickel talc composite was added to a ball mill containing grinding balls to a ball-to-material ratio of 60:1, and the mixture was ball-milled at 100 rpm for 20 h to obtain a ball-milled product;

[0068] (3) The ball-milled product was placed in 5% by volume sulfuric acid, heated in a water bath at 90° C. for 2 h, then washed with ultrapure water until neutral, centrifuged, and dried to obtain a carbon-silicon oxide nanocomposite material containing metal oxides.

[0069] The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite material was calculated by BET method to be 380 m 2 / g, with a large specific surface area and good adsorption performance.

[0070] Example 6

[0071] The only difference between Example 6 and Example 3 is that the ball-to-material ratio in step (2) is 10:1.

[0072] The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite containing metal oxides was calculated by BET method to be 348 m 2 / g, with a large specific surface area and good adsorption performance.

[0073] Example 7

[0074] The only difference between Example 7 and Example 3 is that the volume concentration of hydrochloric acid in step (3) is 5% and the acid treatment time is 3 hours.

[0075] The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite containing metal oxides was calculated by BET method to be 382 m 2 / g, with a large specific surface area and good adsorption performance.

[0076] Example 8

[0077] An embodiment of the application of the carbon-silicon oxide nanocomposite material of the present invention to the treatment of organic pollutants is to use it as an adsorbent for volatile organic pollutants.

[0078] The carbon-silicon oxide nanocomposite material without metal oxide prepared in Example 1 was used for benzene adsorption experiment. The breakthrough curve of benzene adsorption was as follows: Figure 5 The static adsorption capacity of the material for benzene is 324 mg / g, and the dynamic adsorption capacity is 180 mg / g.

[0079] The carbon-silicon oxide nanocomposite material prepared in Example 2 was used in a toluene dynamic adsorption experiment, and the dynamic saturated adsorption capacity of the material for toluene was 152 mg / g.

[0080] The prepared carbon-silicon oxide nanocomposite material has a good adsorption effect on volatile organic pollutants benzene and toluene.

[0081] Example 9

[0082] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention is applied to the treatment of organic pollutants, in which the application mode is to be used as a catalyst carrier.

[0083] The carbon-silicon oxide nanocomposite material containing no metal oxides prepared in Example 1 was used as a carrier, and platinum nanoparticles were loaded thereon by an impregnation method to prepare a platinum-carbon-silicon oxide catalyst.

[0084] The catalyst was used in an experiment to catalyze the degradation of volatile organic compound toluene under the following conditions: toluene concentration of 1000 ppm, gas flow rate of 80 mL / min, and gas hourly space velocity of 60000 mL / (g·h).

[0085] The effect of the catalytic degradation of toluene by the above platinum-carbon-silicon oxide catalyst is as follows: Figure 6 The results showed that the platinum-carbon-silicon oxide catalyst could achieve a toluene conversion rate of 90% at 200°C and had a good catalytic degradation effect on toluene.

[0086] Example 10

[0087] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention is applied to the treatment of organic pollutants, in which the application mode is to be used as a catalyst carrier.

[0088] The carbon-silicon oxide nanocomposite material containing metal oxides prepared in Example 3 was used as a carrier, and platinum nanoparticles were loaded by an impregnation method to prepare a platinum-carbon-silicon oxide catalyst.

[0089] The catalyst was used in an experiment to catalyze the degradation of volatile organic compound toluene under the following conditions: toluene concentration of 1000 ppm, gas flow rate of 80 mL / min, and gas hourly space velocity of 60000 mL / (g·h).

[0090] The effect of catalytic degradation of toluene by the three cycles of the platinum-carbon-silicon oxide catalyst is as follows: Figure 7 Results showed that the platinum-carbon-silicon oxide catalyst achieved a 90% toluene conversion rate at 205°C, demonstrating excellent catalytic degradation of toluene. Furthermore, due to the large surface area and abundant anchoring sites of the carbon-silicon oxide support, the loaded platinum was highly dispersed and further reduced to platinum nanoparticles during the catalytic experiment, resulting in improved performance after three cycles of testing.

[0091] Example 11

[0092] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention is applied to the treatment of organic pollutants, in which the application mode is to be used as a catalyst carrier.

[0093] The carbon-silicon oxide nanocomposite material containing metal oxides prepared in Example 5 was used as a carrier, and platinum nanoparticles were loaded by an impregnation method to prepare a platinum-carbon-silicon oxide catalyst.

[0094] The catalyst was used in an experiment to catalyze the degradation of volatile organic compound toluene under the following conditions: toluene concentration of 1000 ppm, gas flow rate of 80 mL / min, and gas hourly space velocity of 60000 mL / (g·h).

[0095] The catalyst was used in an experiment to catalyze the degradation of volatile organic compound toluene. A toluene conversion rate of 90% was achieved at 193° C., showing a good catalytic degradation effect on toluene.

[0096] Example 12

[0097] An embodiment of the carbon-silicon oxide nanocomposite material of the present invention being applied to a lithium electronic battery comprises the following steps:

[0098] (1) The carbon-silicon oxide nanocomposite material without metal oxide prepared in Example 1 was used as a precursor, and mixed with a metal reducing agent (magnesium powder) and sodium chloride in a mass ratio of 1:0.8:3;

[0099] (2) The mixture was placed in a tube furnace, inert gas was introduced, and the temperature was slowly raised to 650°C, kept at this temperature for 5 h, and then naturally cooled to room temperature;

[0100] (3) After cooling, washing with dilute hydrochloric acid for 5 h, then washing with ultrapure water until neutral, and vacuum drying to obtain a silicon / silicon carbide / carbon nanocomposite material;

[0101] (4) The prepared silicon / silicon carbide / carbon nanocomposite material is used to prepare the negative electrode of a lithium-ion battery, and then assembled into a lithium-ion battery.

[0102] Silicon carbide and the composite of carbon and silicon make the material highly stable in structure, and the carbon therein has a high degree of graphitization, the material has good electrical conductivity, and the assembled battery exhibits good electrochemical lithium storage performance.

[0103] Example 13

[0104] The only difference between Example 13 and Example 1 is that the mass ratio of clay mineral to organic matter is 1:0.01.

[0105] The specific surface area of ​​the obtained carbon-silicon oxide nanocomposite material was calculated by BET method to be 417 m 2 / g, and has good adsorption performance; but its conductivity is poor and it cannot be used in the preparation of negative electrode precursors for lithium-ion batteries.

[0106] Example 14

[0107] The only difference between Example 14 and Example 5 is that the volume concentration of sulfuric acid in step (3) is 15%, and a carbon-silicon oxide nanocomposite material free of metal oxides is prepared.

[0108] A platinum-carbon-silicon oxide catalyst was prepared by impregnation-loading platinum nanoparticles onto the carbon-silicon oxide nanocomposite containing metal oxides prepared in this example. The catalyst was used to catalyze the degradation of the volatile organic compound toluene under the following conditions: a toluene concentration of 1000 ppm, a gas flow rate of 80 mL / min, and a gas hourly space velocity of 60,000 mL / (g·h).

[0109] In the experiment of catalytic degradation of volatile organic compound toluene, a toluene conversion rate of 90% was achieved at 198°C, and the catalytic performance was slightly lower than that of the carbon-silicon oxide nanocomposite material containing metal oxide as a carrier in Example 5 (compared with the results of Example 11).

[0110] Comparative Example 1

[0111] The only difference between Comparative Example 1 and Example 1 is that the ball milling in step (2) is removed, and the carbon / montmorillonite composite is directly subjected to acid treatment to obtain a composite product.

[0112] The obtained composite product was analyzed by X-ray diffraction spectroscopy (XRD). Figure 7.Depend on Figure 8 It can be seen that: the product still has obvious diffraction peaks of montmorillonite, and it is impossible to obtain a carbon-silicon oxide nanocomposite material.

[0113] The specific surface area of ​​the product was only 33 m 2 / g, the specific surface area is small; in the benzene adsorption experiment, the adsorption capacity of the composite product for benzene is 25.6 mg / g, and the adsorption performance is poor.

[0114] Comparative Example 2

[0115] The difference between Comparative Example 2 and Example 1 is only in the preparation sequence: step (2) ball milling and step (3) acid treatment, washing and drying are first performed, and then step (1) high temperature carbonization is performed to obtain a composite product.

[0116] The carbon-containing components in the obtained composite product are lost, and the carbon-silicon oxide nanocomposite material cannot be obtained.

[0117] Comparative Example 3

[0118] The only difference between Comparative Example 3 and Example 1 is that the ball-to-material ratio in step (2) ball milling is 5:1.

[0119] The obtained composite product was analyzed by X-ray diffraction spectroscopy (XRD). The product had obvious diffraction peaks of montmorillonite at around 2θ=6° and 20°, and no carbon-silicon oxide nanocomposite material could be obtained.

[0120] Comparative Example 4

[0121] The only difference between Comparative Example 4 and Example 1 is that the ball-to-material ratio in step (2) ball milling is 100:1.

[0122] After ball milling, a large amount of ball milling products adhere to the grinding balls and inner walls, causing unnecessary and large losses.

[0123] Comparative Example 5

[0124] The only difference between Comparative Example 5 and Example 1 is that hydrochloric acid with a volume concentration of 1% is used in step (3).

[0125] The obtained composite product was analyzed by X-ray diffraction spectroscopy (XRD). The product had obvious diffraction peaks of montmorillonite at around 2θ=6° and 20°, and no carbon-silicon oxide nanocomposite material could be obtained.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a carbon-silicon oxide nanocomposite material based on clay minerals, characterized in that: The preparation method consists of the following steps: (1) Carbonizing a carbonaceous clay mineral in an inert atmosphere to obtain a clay mineral composite; the carbonaceous clay mineral is a natural carbonaceous clay mineral or an organic-modified clay mineral; the natural carbonaceous clay mineral includes black talc; the carbonization temperature is 500-800°C, and the carbonization time is 2-5 hours; in the organic-modified clay mineral, the mass ratio of clay mineral to organic matter is 1:(0.05-2); (2) Grinding the clay mineral composite obtained in step (1) to obtain a ground product; the grinding method is ball milling; the ball-to-material ratio of the ball milling is (10-60):1, the ball milling speed is 100-700 rpm, and the ball milling time is 2-20 hours; (3) treating the ground product obtained in step (2) with acid, then washing and drying to obtain the carbon-silicon oxide nanocomposite material; in the acid treatment, the volume concentration of the acid in the acid solution is 5-20%, the acid treatment temperature is 60-90° C., the acid treatment time is 1-24 h, and the acid is at least one of hydrochloric acid, sulfuric acid and nitric acid.

2. The method for preparing a carbon-silicon oxide nanocomposite material based on clay minerals according to claim 1, characterized in that: In step (1), the clay mineral modified by organic matter includes at least one of montmorillonite, palygorskite, kaolinite, sepiolite, talc, illite, saponite, serpentine and chlorite.

3. The method for preparing a carbon-silicon oxide nanocomposite material based on clay minerals according to claim 1, characterized in that: In step (3), the acid treatment time is 1-4 hours, and the volume concentration of the acid in the acid solution is 5-10%, thereby preparing a carbon-silicon oxide nanocomposite material containing metal oxides.

4. The carbon-silicon oxide nanocomposite material prepared according to the method for preparing a clay mineral-based carbon-silicon oxide nanocomposite material according to any one of claims 1 to 3.

5. Use of the carbon-silicon oxide nanocomposite material according to claim 4 in the treatment of organic pollutants.

6. Use of the carbon-silicon oxide nanocomposite material according to claim 4 in lithium electronic batteries.

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