Graphene-supported silica composite material, its preparation method and application

Abstract

The present invention provides a graphene-supported silica composite material, a preparation method thereof and an application thereof. The preparation method includes: S1, preparing a sodium silicate solution; S2, preparing a graphene oxide dispersion; S3, forming a mixed solution of graphene oxide and sodium silicate; S4, dropwise adding the mixed solution of graphene oxide and sodium silicate into an ammonium bicarbonate solution; S5, adding a reducing agent into the mixed solution obtained in step S4; S6, filtering to obtain a solid mixture, and washing and drying the solid mixture; and S7, performing high-temperature treatment on the dried solid mixture. In the composite material prepared by the method of the present invention, silica is attached to the surface of graphene. Therefore, in addition to being able to exert the low heat generation performance of silica, it can also prevent graphene from undergoing secondary agglomeration in rubber. As a rubber filler, the composite material has more excellent processing performance, and its fluidization mechanical properties are also significantly improved, and it can improve the compression heat generation and mechanical properties of rubber.

Description

Technical Field

[0001] The present invention belongs to the technical field of graphene nanomaterials, and particularly relates to a graphene-supported silica composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Graphene is a new material with a single-layer flaky structure composed of carbon atoms. It is a planar film with a hexagonal honeycomb lattice formed by carbon atoms in sp 2 hybrid orbitals, and is a two-dimensional material with a thickness of only one carbon atom. Due to the many excellent physical and chemical properties of graphene, it is widely used in energy storage materials, environmental engineering, and sensitive sensing, and is known as "black gold" or "the king of new materials". Moreover, its potential application prospects are vast. Currently, it has become the focus of attention and research hotspot around the world. In particular, the excellent properties of graphene have realized great prospects for the development of high-performance and multifunctional polymer nanocomposites. However, precisely due to the flaky structure of graphene, it is very easy to agglomerate in polymer materials such as rubber. The agglomerated graphene will form stress concentration points, affecting the performance of the composite material.

[0003] Silica, commonly known as white carbon black, is a white, non-toxic, amorphous white powder with a size of 10 - 40 nm. It has a very large specific surface area and a large number of hydroxyl functional groups, which can greatly reduce the compression heat generation of rubber and is an important filler in rubber composite materials. However, due to the poor strength of white carbon black, the strength of the prepared rubber composite material is also poor.

[0004] Existing research and literature have all reported technical solutions of using graphene and white carbon black as fillers for rubber. The dispersion of graphene in rubber is the key to preparing high-performance rubber composite materials. If the dispersion of the filler is very poor, it is difficult to have good use value. Therefore, solving the dispersion of graphene and white carbon black in the rubber matrix has become the key to their being good rubber fillers.

[0005] Therefore, how to obtain a method that can better disperse graphene and white carbon black uniformly in the rubber matrix and give full play to the reinforcement of graphene and the low heat generation performance of white carbon black is the focus of attention of many current researchers and institutions. Summary of the Invention

[0006] The present invention aims to provide a graphene-supported silica material, a preparation method thereof, and an application as a rubber filler.

[0007] The present invention provides a method for preparing a graphene-supported silica composite material, comprising: S1, dissolving sodium silicate in water to prepare a sodium silicate solution; S2, dispersing graphene oxide in water to prepare a graphene oxide dispersion; S3, adding the graphene oxide dispersion to the sodium silicate solution, and then performing a dispersion treatment to form a mixed solution of graphene oxide and sodium silicate; S4, dropwise adding the mixed solution of graphene oxide and sodium silicate into an ammonium bicarbonate solution, and continuously stirring during the dropping process; S5, adding a reducing agent to the mixed solution obtained in the S4 step; S6, filtering the mixed solution after the reaction in the S5 step to obtain a solid mixture, and washing and drying the solid mixture; and S7, performing a high-temperature treatment on the dried solid mixture, the temperature of the high-temperature treatment being 200-800 °C, preferably 260 °C, and the time of the high-temperature treatment being 1-6 h, preferably 2 h.

[0008] According to an embodiment of the present invention, in the S1 step, the concentration of the sodium silicate solution is 1-10 wt%, preferably 5 wt%.

[0009] According to another embodiment of the present invention, in the S2 step, the concentration of the graphene oxide dispersion is 0.1-2 wt%, preferably 1 wt%; preferably, the sheet diameter of the graphene oxide is 2-15 microns, and the sheet thickness of the graphene oxide is 0.7-10 nanometers; preferably, the oxygen content of the graphene oxide is 20-60 wt%.

[0010] According to another embodiment of the present invention, in the S3 step, the mass ratio of the graphene oxide to the sodium silicate is 0.1-10:100.

[0011] According to another embodiment of the present invention, in the S4 step, the concentration of the ammonium bicarbonate is 1-10 wt%; the molar ratio of the ammonium bicarbonate to the sodium silicate is 2.0-3.0:1.

[0012] According to another embodiment of the present invention, in the S5 step, the reducing agent is selected from one or more of vitamin C, hydrazine hydrate, sodium borohydride, hydrogen, ammonia, vitamin C, potassium hydroxide, sodium oxide, dimethylhydrazine, hydroquinone, hydroiodic acid, and phenylhydrazine.

[0013] According to another embodiment of the present invention, the reducing agent is vitamin C, and the mass ratio of the vitamin C to the graphene oxide is 0.5-3:1; the temperature for the vitamin C to reduce the graphene oxide is 50-90 °C, preferably 80 °C; the time for the vitamin C to reduce the graphene oxide is 0.5-4 h, preferably 1 h.

[0014] According to another embodiment of the present invention, during the filtration and washing in step S6, the pH value of the solid-liquid mixture is 5-7.

[0015] The present invention also provides a graphene-supported silica composite material prepared by the above method.

[0016] The present invention further provides an application of the graphene-supported silica composite material as a rubber filler.

[0017] In the composite material prepared by the method of the present invention, silica is attached to the surface of graphene. Therefore, in addition to exerting the low heat build-up performance of silica, it can also separate the sheet-like graphene and prevent its secondary aggregation in rubber. As a rubber filler, this composite material has more excellent processing performance and significantly improved fluidization mechanical properties compared to the rubber compound prepared by directly adding graphene and silica to rubber. It can improve the compression heat build-up and mechanical properties of rubber, and is particularly suitable for tire rubber. And in the method of the present invention, the production route of preparing silica by the existing precipitation method is basically not changed, the equipment modification is small, the production cost will not increase, and the process is simple with high economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the graphene-supported silica of the present invention.

[0019] Figure 2 It is a scanning electron microscope image of the graphene-supported silica prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The technical solutions of the present invention will be further described below through specific examples. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0021] The preparation method of the graphene-supported silica composite material of the present invention includes: S1, dissolving sodium silicate in water to prepare a sodium silicate solution; S2, dispersing graphene oxide in water to prepare a graphene oxide dispersion; S3, adding the graphene oxide dispersion to the sodium silicate solution, and then performing a dispersion treatment to form a mixed solution of graphene oxide and sodium silicate; S4, dropping the mixed solution of graphene oxide and sodium silicate into an ammonium bicarbonate solution, and continuously stirring during the dropping process; S5, adding a reducing agent to the mixed solution obtained in step S4; S6, filtering the mixed solution after the reaction in step S5 to obtain a solid mixture, and washing and drying the solid mixture; and S7, performing a high-temperature treatment on the dried solid mixture, the temperature of the high-temperature treatment is 200-800 °C, preferably 260 °C, and the time of the high-temperature treatment is 1-6 h, preferably 2 h.

[0022] In step S1, the concentration of the sodium silicate solution is 1 to 10 wt%. If the concentration of the sodium silicate solution is too low (below 1 wt%), the subsequent reaction efficiency will be low; if the concentration is too high (above 10 wt%), the sodium silicate cannot completely react in the subsequent reaction, resulting in unnecessary waste. An appropriate concentration range can be selected according to specific circumstances, such as but not limited to 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 10 wt%, etc. Preferably, the concentration of sodium silicate is 5 wt%.

[0023] In step S2, the concentration of the graphene oxide dispersion is 0.1 to 2 wt%. If the concentration of graphene oxide in the dispersion is below 0.1 wt%, the subsequent reaction efficiency will be low; if the concentration is above 2 wt%, the graphene oxide cannot completely react in the subsequent reaction, resulting in unnecessary waste. Preferably, the concentration of graphene oxide in the dispersion is 1 wt%. The sheet diameter of graphene oxide in the dispersion is 2 to 15 microns. If the sheet diameter of graphene oxide is greater than 15 microns, the dispersion effect is not good; however, the sheet diameter of graphene oxide can be lower, but based on cost considerations, the sheet diameter of graphene oxide in the dispersion is selected to be above 2 microns. The sheet thickness of graphene oxide in the dispersion is 0.7 to 10 nanometers. If the sheet thickness is greater than 10 nanometers, the number of layers of graphene oxide is relatively large, so it cannot play a strengthening role. Graphene oxide with a thickness below 0.7 nanometers can still achieve the object of the present invention, but the cost is too high. Based on cost considerations, it is preferred that the sheet thickness of graphene oxide is above 0.7 nanometers. Those skilled in the art can select any value within the above range according to actual needs, such as but not limited to 1 nanometer, 2 nanometers, 3 nanometers, 4 nanometers, 5 nanometers, 6 nanometers, 7 nanometers, 8 nanometers, 9 nanometers, 10 nanometers, etc. Specific layers of graphene can also be selected, such as 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, 9 layers, 10 layers, 11 layers, 12 layers, 13 layers, 14 layers, 15 layers, 16 layers, 17 layers, 18 layers, 19 layers, 20 layers, etc. The oxygen content of graphene oxide in the dispersion is 20 to 60 wt%. When the oxygen content in graphene oxide is below 20 wt%, its dispersion performance in the dispersion is not good; if the oxygen content of graphene oxide is too high, the price is relatively high, and in addition, it cannot be achieved technically. Therefore, it is preferred that the oxidation amount of graphene oxide is between 20 wt% and 60 wt%. Those skilled in the art can select any value within the above range according to actual needs, such as but not limited to 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, etc.

[0024] In step S3, the mass ratio of graphene oxide to sodium silicate is 0.1-10:100. When the mass ratio of graphene oxide to sodium silicate is lower than 0.1:100, the content of graphene in the composite material is too low, and the enhancement effect of graphene is not obvious; if the mass ratio of graphene oxide to sodium silicate is higher than 1:100, graphene cannot be fully dispersed during the formation of the composite material, which will also reduce the performance of the composite material. Those skilled in the art can select any value within the above range according to actual needs, such as but not limited to 0.1:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, 1.5:100, 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100, 5:100, 5.5:100, 6:100, 6.5:100, 7:100, 7.5:100, 8:100, 8.5:100, 9:100, 9.5:100, 10:100, etc.

[0025] In step S4, the concentration of ammonium bicarbonate is 1-10 wt%. When the concentration of ammonium bicarbonate is lower than 1 wt%, the subsequent reaction will be incomplete; when the concentration of ammonium bicarbonate in the solution is higher than 10 wt%, the graphene oxide in the solution will agglomerate. Therefore, the concentration of ammonium bicarbonate can be selected as any value within the above range, such as but not limited to 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc. The mass of the ammonium bicarbonate solution is calculated according to the molar mass of sodium silicate contained in the sodium silicate solution, and the molar ratio of ammonium bicarbonate to sodium silicate is 2.0-3.0:1. When the molar ratio of ammonium bicarbonate to sodium silicate is lower than 2.0:1, the reaction is incomplete; when the molar ratio of ammonium bicarbonate to sodium silicate is higher than 3.0:1, ammonium hydrogen silicate is excessive, resulting in waste.

[0026] In step S5, graphene oxide is preliminarily reduced. The reducing agent is selected from one or more of vitamin C, hydrazine hydrate, sodium borohydride, hydrogen, ammonia, vitamin C, potassium hydroxide, sodium oxide, dimethylhydrazine, p-benzenediol, hydroiodic acid, phenylhydrazine. When the reducing agent is vitamin C, the mass ratio of vitamin C to graphene oxide is 0.5-3:1. The temperature for vitamin C to reduce graphene oxide is 50-90 °C, preferably 80 °C. The time for vitamin C to reduce graphene oxide is 0.5-4 h, preferably 1 h. The above reaction conditions are the preferred parameters for the reaction of vitamin C and graphene oxide. When other reducing agents are selected, those skilled in the art can select appropriate mass ratios, reaction temperatures, times, etc. according to the types of reducing agents.

[0027] In step S6, the pH value of the solid-liquid mixture during filtration and washing is 5-7. The filtration can be suction filtration. The suction filtration process can be as follows: the mixed solution after the reaction in step S5 is processed to obtain a solid mixture, the filter cake is added to an excessive amount of water again, while stirring, dilute hydrochloric acid is added dropwise to adjust the pH value to 5-7. The excessive water is 5-20 times the mass of the filter cake. The molar mass of the dilute hydrochloric acid is 0.1-2 mol / L. The dilute hydrochloric acid can be one or several of dilute sulfuric acid, dilute nitric acid, and acetic acid. The purpose of the above steps is to wash the solid mixture, and after washing, the solid mixture is dried. The drying treatment can be one or several of blast drying, vacuum drying, and freeze drying. When using blast drying, the drying temperature is 60-120 °C, preferably 80 °C. The drying time is 2 h-10 h, preferably 6 h. Spray drying can also be carried out. When spray drying, the pH value of the solution containing the solid mixture can be adjusted between 5-7, and then the mixed solution is directly spray dried. The drying temperature of spray drying is 100-200 °C, preferably 150 °C.

[0028] In step S7, the dried solid mixture is subjected to high-temperature treatment. During the high-temperature treatment process, graphene oxide will be further reduced. The temperature of the high-temperature treatment is 200-800 °C. If the temperature of the high-temperature treatment is higher than 800 °C, graphene will be decomposed, and if the temperature is lower than 200 °C, the moisture in silica white cannot be completely removed. Preferably, it is 260 °C. The time of the high-temperature treatment is 1-6 h. If the treatment time is too long, graphene is prone to decomposition, and if the time is too short, the moisture in silica white cannot be completely removed.

[0029] The present invention also discloses a graphene-supported silica composite material prepared by the above method. The microscopic schematic diagram of the graphene-supported silica composite material prepared by the method of the present invention is as Figure 1 shown, that is, silica white particles 2 are supported on the surface of graphene sheets 1. Therefore, in addition to being able to exert the low heat generation performance of silica white, it can also separate the sheet-like graphene and prevent its secondary aggregation in rubber. The graphene-supported silica composite material prepared by the above method can be used as a rubber filler. As a rubber filler, this composite material has more excellent processing performance and significantly improved fluidization mechanical properties compared with the rubber compound prepared by directly adding graphene and silica white to rubber. It can improve the compression heat generation and mechanical properties of rubber, and is especially suitable for tire rubber. And in the method of the present invention, the production route of preparing silica white by the existing precipitation method is basically not changed, the equipment modification is small, the production cost will not increase, and the process is simple with high economic value.

[0030] Example 1

[0031] (1) Add water into the reaction kettle, use an oil bath to heat and control the temperature of the water at 80 °C, add powdered instant sodium silicate, and prepare a sodium silicate solution with a concentration of 5 wt%. During the whole process of preparing the sodium silicate solution, the temperature is maintained at 80 °C.

[0032] (2) Take graphene oxide accounting for 2% of the mass of sodium silicate, add it into deionized water, and stir at high speed for 2 h. The graphene oxide is 10 layers, with a sheet diameter of 2 microns and an oxygen content of 30 wt%.

[0033] (3) Disperse the treated graphene oxide into the sodium silicate solution, and homogenize the mixed solution using a high-pressure homogenizer. The homogenization pressure is 800 bar, and the homogenization time is 1 h.

[0034] (4) Take ammonium bicarbonate, add it into water, and heat to 30 °C to prepare a 2.4 mol / L ammonium bicarbonate solution.

[0035] (5) Slowly add the prepared mixed solution of graphene oxide and sodium silicate into the ammonium bicarbonate solution drop by drop using a peristaltic pump, and continuously stir.

[0036] (6) Add 1 wt% aqueous solution of vitamin C into the reactants in step (5), heat with an oil bath to 80 °C, and react for 1 h.

[0037] (7) Filter the product in step (6) by suction filtration. Add the filter cake into excessive water, stir until it is completely dispersed, and adjust the pH value to 7 with 1 mol / L dilute hydrochloric acid.

[0038] (8) Filter the mixture with the adjusted pH value by suction filtration, and dry the filter cake in a blast drying oven at 80 °C for 6 h.

[0039] (9) Heat-treat the dried solid at 260 °C for 2 h to obtain the graphene-supported silica material.

[0040] Example 2

[0041] Except that the mass of graphene oxide in step (2) is 4 wt% of the mass of sodium silicate, other steps are the same as those in Example 1.

[0042] Example 3

[0043] (1) Add water into the reaction kettle, use an oil bath to heat and control the temperature of the water at 80 °C, add powdered instant sodium silicate, and prepare a sodium silicate solution with a concentration of 5 wt%. During the whole process of preparing the sodium silicate solution, the temperature is maintained at 80 °C.

[0044] (2) Take graphene oxide accounting for 2 wt% of the mass of sodium silicate, add it into deionized water, and stir at high speed for 2 h. The graphene oxide is 10 layers, with a sheet diameter of 2 microns and an oxygen content of 30 wt%.

[0045] (3) Add the processed graphene oxide dispersion to the sodium silicate solution, and use high-speed stirring to process the mixed solution for 2 h at a rotation speed of 3000 r / min.

[0046] (4) Take ammonium bicarbonate and add it to water, heat it to 30 °C, and prepare a 2.4 mol / L ammonium bicarbonate solution.

[0047] (5) Gradually add the prepared mixed solution of graphene oxide and sodium silicate to the ammonium bicarbonate solution using a peristaltic pump, and continuously stir.

[0048] (6) Add 1 wt% aqueous solution of vitamin C to the reactants in step (5), heat in an oil bath to 60 °C, react for 3 h, and then adjust the pH value to 7 with dilute hydrochloric acid.

[0049] (7) Spray-dry the mixture with the adjusted pH value, and the drying temperature is 120 °C.

[0050] (8) Heat-treat the dried solid at 400 °C for 2 h to obtain the graphene-supported silica material.

[0051] Example 4

[0052] Except that the mass of graphene oxide in step (2) is 4 wt% of the mass of sodium silicate, other steps are the same as in Example 3.

[0053] Comparative Example 1

[0054] This comparative example refers to Example 1, and the difference is that steps (2) and (3) are absent.

[0055] Comparative Example 2

[0056] This comparative example refers to Example 1, and the differences are: steps (2) and (3) are absent, and 2 wt% of graphene oxide based on the mass of sodium silicate is directly mixed with the solid obtained in step (7) and then step (8) is carried out.

[0057] Comparative Example 3

[0058] This comparative example refers to Example 3, and the difference is that steps (2) and (3) are absent.

[0059] Comparative Example 4

[0060] This comparative example refers to Example 3, and the differences are: steps (2) and (3) are absent, and 2 wt% of graphene oxide based on the mass of sodium silicate is directly mixed with the solid obtained in step (7) and then step (8) is carried out.

[0061] Perform electron microscopy scanning on the composite material prepared in Example 1, and the photo is as Figure 2 shown. FromFigure 2 It can be seen that the silica is loaded on the surface of the graphene sheets. This proves that the method of the present invention can indeed load the silica on the surface of the graphene sheets, thereby fully utilizing the low heat build-up performance of the silica and preventing the agglomeration of the graphene.

[0062] The rubber compounds were prepared using the composite materials prepared in Examples 1-4 and Comparative Examples 1-4, and the prepared rubber compounds were tested.

[0063] The preparation method is as follows:

[0064] The formulation is as follows: smoked sheet rubber (3#), 70 g; cis-butadiene rubber (BR9000), 30 g, graphene-supported silica, 100 g; Si69, 1 g; zinc oxide, 5 g; stearic acid, 2 g; antioxidant (RD), 3.5 g; antioxidant (4020), 2 g; microcrystalline wax, 1 g; accelerator (D), 2.1 g; accelerator (CZ) 2 g; sulfur, 4 g.

[0065] This formulation was prepared according to the following preparation method:

[0066] (1) Adjust the roll gap to 1 mm, add the smoked sheet rubber and cis-butadiene rubber, then break the rubber once without wrapping it around the roll, and then wrap the rubber compound around the roll.

[0067] (2) Slowly and evenly add sulfur. When the sulfur is mixed, make a 3 / 4 cut from both ends of the roll every 20 s, and make 6 cuts (alternate cuts are regarded as one cut). The operation time is 4 min.

[0068] (3) Evenly add zinc oxide, make a 3 / 4 cut from both ends of the roll every 20 s, and make 2 cuts. The operation time is 1.5 min.

[0069] (4) Evenly add stearic acid, make a 3 / 4 cut from both ends of the roll every 20 s, and make 2 cuts. The operation time is 1.5 min.

[0070] (5) Add 1 / 3 of the silica, make a 3 / 4 cut from both ends of the roll every 20 s, and make 4 cuts. The operation time is 5 min.

[0071] (6) Add 1 / 3 of the silica, make a 3 / 4 cut from both ends of the roll every 20 s, and make 4 cuts. The operation time is 5 min.

[0072] (7) After adding 1 / 3 of the silica, add the activator PEG4000, make a 3 / 4 cut from both ends of the roll every 20 s, and make 6 cuts. The operation time is 8.5 min.

[0073] (8) Slowly and evenly cover the accelerator on the rubber and add it. After all the materials are mixed, make a 3 / 4 cut with a cutter at both ends of the roller alternately every 20 s, make 4 cuts, and the operation time is 3.5 min.

[0074] (9) Cut the rubber sheet from the rubber mixing mill and wrap it in a triangular shape 3 times. The operation time is 1.5 min.

[0075] (10) Cut the rubber sheet from the rubber mixing mill, adjust the roller gap to 2 mm, and pass the rubber compound through the roller 3 times without wrapping the roller. The operation time is 1 min.

[0076] (11) Cut the rubber compound from the rubber sheet. Total operation time: 31.5 min.

[0077] (12) Remove the rubber sheet and make marks in the direction of sheet extrusion.

[0078] The rubber compound can be subjected to relevant processing performance and mechanical property tests after being placed at room temperature for 24 hours. The test results are shown in Table 1:

[0079] Table 1 Variation of processing performance and mechanical properties of graphene-loaded silica rubber with reaction conditions

[0080]

[0081] The vulcanization time T90 represents: the time required for the rubber compound to rise from the start of heating to 90% of the maximum torque, and m:s represents that the unit of time is minutes and seconds.

[0082] From the results of the above-mentioned examples and comparative examples, it can be seen that the silica obtained by the method of the present invention has excellent processing performance in tire rubber, and the mechanical properties of the vulcanized rubber also increase significantly. The method provided by the present invention is simple, does not require the addition of silane coupling agents or other additives, does not increase the production cost, and has good technical economy. The comparative example did not adopt the solution of the present invention, so the excellent effects of the present invention could not be achieved.

[0083] The applicant declares that the present invention uses the above-mentioned examples to illustrate the detailed method of the present invention, but the present invention is not limited to the above-mentioned detailed method, that is, it does not mean that the present invention must rely on the above-mentioned detailed method to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and disclosure scope of the present invention. The following further describes the present invention through specific examples. However, these examples are only exemplary and do not constitute any limitation to the protection scope of the present invention.

Claims

1. A method for preparing a graphene-supported silica composite material, characterized in that, Including: S1, dissolving sodium silicate in water to prepare a sodium silicate solution; S2, dispersing graphene oxide in water to prepare a graphene oxide dispersion; S3, adding the graphene oxide dispersion to the sodium silicate solution, and then performing a dispersion treatment to form a mixed solution of graphene oxide and sodium silicate; S4, dropwise adding the mixed solution of graphene oxide and sodium silicate to an ammonium bicarbonate solution, and continuously stirring during the dropping process; S5, adding a reducing agent to the mixed solution obtained in step S4; S6, filtering the mixed solution after the reaction in step S5 to obtain a solid mixture, and washing and drying the solid mixture; and S7, performing a high-temperature treatment on the dried solid mixture, the temperature of the high-temperature treatment is 200 - 800 °C, and the time of the high-temperature treatment is 1 - 6 h; In step S1, the concentration of the sodium silicate solution is 1 - 10 wt%; In step S2, the concentration of the graphene oxide dispersion is 0.1 - 2 wt%, the sheet diameter of the graphene oxide is 2 - 15 microns, and the oxygen content of the graphene oxide is 20 - 60 wt%; In step S3, the mass ratio of the graphene oxide to the sodium silicate is 0.1 - 10:100; In step S4, the concentration of the ammonium bicarbonate is 1 - 10 wt%, and the molar ratio of the ammonium bicarbonate to the sodium silicate is 2.0 - 3.0:1; Wherein, the silica white particles in the graphene-supported silica composite material are loaded on the surface of the graphene sheets.

2. The preparation method according to claim 1, characterized in that, In step S1, the concentration of the sodium silicate solution is 5 wt%.

3. The preparation method according to claim 1, characterized in that, In step S2, the concentration of the graphene oxide dispersion is 1 wt%.

4. The preparation method according to claim 1, wherein, In step S5, the reducing agent is selected from one or more of vitamin C, hydrazine hydrate, sodium borohydride, hydrogen, ammonia, potassium hydroxide, sodium oxide, dimethylhydrazine, hydroquinone, hydroiodic acid, phenylhydrazine.

5. The preparation method according to claim 4, characterized in that The reducing agent is vitamin C, the mass ratio of the vitamin C to the graphene oxide is 0.5 - 3:1; the temperature for the vitamin C to reduce the graphene oxide is 50 - 90 °C; the time for the vitamin C to reduce the graphene oxide is 0.5 - 4 h.

6. The preparation method according to claim 5, characterized in that, The temperature for the vitamin C to reduce the graphene oxide is 80 °C; the time for the vitamin C to reduce the graphene oxide is 1 h.

7. The preparation method according to claim 1, characterized in that, In step S6, the pH value of the solid-liquid mixture during the filtration and washing is 5 - 7.

8. The preparation method according to claim 1, characterized in that, In step S7, the temperature of the high-temperature treatment is 260 °C, and the time of the high-temperature treatment is 2 h.

9. A graphene-supported silica composite material, characterized in that, The composite material is prepared by the method according to any one of claims 1 - 8.

10. Use of the graphene-supported silica composite material according to claim 9 as a rubber filler.

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