阅读说明：本技术 一种石墨烯复合二氧化硅电化学电极的制备方法 (Preparation method of graphene composite silicon dioxide electrochemical electrode ) 是由 谢逾群 万端极 刘德富 于 2019-08-02 设计创作，主要内容包括：本发明涉及一种石墨烯复合二氧化硅电化学电极的制备方法。包括步骤(1)二氧化硅纳米改性载体的制备：步骤(2)石墨烯电极的制备。在本制备方法中,通过创造高温无氧的条件,使碳源在二氧化硅纳米改性载体上分解再重组,在电极上形成一层石墨烯层。使用本方法所制备的石墨烯电极,电阻低,寿命长,稳定性好,抗氧化性与耐腐蚀性能力都比较强；作为电极反应灵敏,制备方案高效、安全。有效解决现有工艺制备电极不经济、不安全、寿命短、稳定性差等问题。(The invention relates to a preparation method of a graphene composite silicon dioxide electrochemical electrode. The preparation method comprises the following steps of (1) preparation of the silicon dioxide nano modified carrier: and (3) preparing the graphene electrode in the step (2). In the preparation method, a carbon source is decomposed and recombined on the silicon dioxide nano modified carrier by creating a high-temperature oxygen-free condition, and a graphene layer is formed on an electrode. The graphene electrode prepared by the method has low resistance, long service life, good stability and stronger oxidation resistance and corrosion resistance; the electrode has sensitive reaction, and the preparation scheme is efficient and safe. Effectively solves the problems of uneconomic, unsafe, short service life, poor stability and the like of the electrode prepared by the prior art.)

1. A preparation method of a graphene composite silicon dioxide electrochemical electrode is characterized by comprising the following steps:

step (1) preparation of silicon dioxide nano modified carrier:

dissolving vinyl trimethoxy silane in absolute ethyl alcohol and uniformly stirring;

step (1.2) adding a solid silicon dioxide carrier into the solution obtained in the step (1.1) and adjusting the pH value by using ammonia water;

step (1.3) reacting the solution obtained in step (1.2) for a period of time under the condition of constant temperature;

step (1.4), the reacted silicon dioxide nano modified carrier is placed in a constant temperature drying oven to be dried;

step (2) preparation of graphene electrodes:

step (2.1) placing the silicon dioxide nano modified carrier obtained in the step (1) into a clean quartz boat;

step (2.2) pushing the quartz boat filled with the silicon dioxide nano modified carrier into the middle of a tubular muffle furnace;

step (2.3), setting the temperature and time of the muffle furnace, carrying out temperature programming, and introducing nitrogen gas;

step (2.4) after the muffle furnace reaches the set temperature, closing the nitrogen, simultaneously introducing the petroleum waste heated to the preset temperature into the tubular muffle furnace, and starting timing to perform reaction;

closing the petroleum waste control pipe valve and the muffle furnace after the reaction is finished, and introducing nitrogen;

and (2.6) cooling the muffle furnace to room temperature under the condition of filling nitrogen, and taking out the quartz boat in the tube to obtain the silicon dioxide nano modified composite electrode with the surface attached with the graphene layer.

2. The method for preparing the graphene composite silicon dioxide electrochemical electrode according to claim 1, wherein the ratio of the amount of the vinyltrimethoxysilane to the absolute ethyl alcohol in the step (1.1) is 1g to 5 ml.

3. The method for preparing the graphene composite silica electrochemical electrode according to claim 1, wherein the pH value is adjusted to 9-11 in the step (1.2).

4. The preparation method of the graphene composite silicon dioxide electrochemical electrode according to claim 1, wherein the reaction temperature in the step (1.3) is 38-42 ℃, the reaction time is 2-3h, and the reaction is carried out under stirring.

5. The method for preparing the graphene composite silicon dioxide electrochemical electrode as claimed in claim 1, wherein the temperature of the drying box in the step (1.4) is 110-120 ℃, and the drying time is 10-12 h.

6. The method for preparing the graphene composite silicon dioxide electrochemical electrode as claimed in claim 1, wherein the nitrogen gas introduction rate in the steps (2.3) and (2.5) is 150-200 mL/min.

7. The method for preparing the graphene composite silicon dioxide electrochemical electrode as claimed in claim 1, wherein the muffle furnace temperature in the step (2.4) is set to 900-.

8. The preparation method of the graphene composite silica electrochemical electrode according to claim 1, wherein the reaction time in the step (2.4) is 35-40 min.

9. The preparation method of the graphene composite silica electrochemical electrode according to claim 1, wherein the cooling time of the muffle furnace in the step (2.6) is 4-5 hours to room temperature.

Technical Field

The invention relates to a preparation method of a thermal cracking graphene nano-modified composite silicon dioxide nano-modified electrode, in particular to a production process for preparing a graphene material by taking a silicon dioxide nano-modified material as a carrier and petroleum waste as a raw material and then compounding the graphene material on the carrier to form an electrochemical electrode.

Background

The following electrochemical electrodes are commonly used:

(1) a platinum electrode, one of the common working electrodes. A diameter of platinum wire and copper wire are typically welded together, with the entire platinum wire (with one end exposed) and a distance above the copper and platinum wire interface being coated with epoxy. The bare end of the platinum wire can be repeatedly and uniformly rubbed on the polishing paper for polishing before each use, so that the reproducibility of the electrode can be ensured. However, such electrodes have a low working potential, usually 1.6V, and are very easily oxidized, so that manual correction is required when they are used.

(2) Copper electrode, one of the common working electrodes. But not strong corrosion resistance and easy generation of Cu₂0 and CuO/Cu (OH)₂The mixture of (2) passivates the surface of the copper electrode, and has low working voltage and poor oxidation resistance.

(3) Lead dioxide titanium-based electrode. The electrode is coated with SnCl by electroplating₄、Sb₂O₃Lead dioxide is plated on the titanium-based matrix which is prepared into mixed solution with butanol, so that the titanium-based matrix has better conductivity and higher stability to strong acid. However, the redox potential is as high as 2.8V, the lead dioxide titanium-based electrode is easy to oxidize to form a loose structure, and the loose structure electrode causes large deviation of the detection result, so that the accuracy of the detection result can be ensured only by regenerating the electrode or frequently replacing the electrode during use, and the coating process is complex and has high cost, so that the problem of matrix passivation cannot be fundamentally solved.

(4) A synthetic diamond boron based electrode. Using boron-doped diamond (BDD) film as electrode material, and the special sp of the BDD film³The bond structure and the conductivity of the bond structure endow the diamond film electrode with excellent electrochemical properties, such as a wide electrochemical potential window, lower background current, better physical and chemical stability, low adsorption property and the like, but the electrode is quite complex to manufacture and quite expensive. Typically one small electrode plate is around $ 5-8 million.

(5) A graphene electrode. One preparation method comprises the following steps: dissolving lithium iron phosphate and polyvinylidene fluoride in a solvent N # methyl pyrrolidone to form a mixed solution, and stirring the mixed solution in a stirrer for 2 to 6 hours; coating the stirred mixed solution on a positive electrode substrate, and drying and rolling at a drying temperature of more than 100 ℃; and spin-coating single-layer graphene on a positive electrode substrate with a positive electrode material at a temperature of more than 100 ℃ by molecular beam epitaxy to obtain the conductive substrate of the multilayer composite film electrode. The method has the defects that the preparation method is complex, the process is complicated, the required electrode can be obtained by multiple steps, single-layer graphene needs to be purchased additionally, and the like.

Key materials for this study

Graphene (Graphene) is a new material composed of carbon atoms hybridized in sp2 to form a honeycomb structure with a thickness of only one carbon atom in a two-dimensional plane. Due to the uniqueness of the structure, the material has excellent optical, electrical and mechanical properties, has important application prospects in the aspects of chemistry, materials, physics, biology, environment, energy and the like, and is considered to be a revolutionary material in the future. Meanwhile, the method for preparing graphene is usually a chemical vapor Deposition method (CVD for short). The CVD method is that organic and small molecules are used as a carbon source, graphene is generated on the surface of a certain template in a high-temperature and low-pressure environment, and specifically the carbon source is adsorbed on the surface of a metal substrate at a certain temperature and pressure; the adsorbed carbon source is pyrolyzed at high temperature, and carbon atoms are subjected to nucleation reconstruction on the surface of the metal matrix; the graphene growth nuclei grow gradually in the subsequent growth process, and finally contact with the boundaries of adjacent growth nuclei to form a crystal boundary.

Pure silicon dioxide is colorless, solid at normal temperature and has a chemical formula of SiO₂And is insoluble in water. Insoluble in acid, and the silicon dioxide material has the advantages of stable chemical property, high heat conductivity coefficient, small thermal expansion coefficient, good wear resistance and the like.

Disclosure of Invention

To overcome the problems and disadvantages of the prior art, it is an object of the present invention to manufacture a working electrode having excellent conductivity and strong oxidation resistance. The electrode has the characteristics of long service life, good stability, and strong oxidation resistance and corrosion resistance.

In order to achieve the purpose, the invention adopts the technical scheme that: a preparation method of a graphene composite silicon dioxide electrochemical electrode is characterized by comprising the following steps:

step (1) preparation of silicon dioxide nano modified carrier:

dissolving vinyl trimethoxy silane in absolute ethyl alcohol and uniformly stirring;

step (1.2) adding a solid silicon dioxide carrier into the solution obtained in the step (1.1) and adjusting the pH value by using ammonia water;

step (1.3) reacting the solution obtained in step (1.2) for a period of time under the condition of constant temperature;

step (1.4), the reacted silicon dioxide nano modified carrier is placed in a constant temperature drying oven to be dried;

step (2) preparation of graphene electrodes:

step (2.1) placing the silicon dioxide nano modified carrier obtained in the step (1) into a clean quartz boat;

step (2.2) pushing the quartz boat filled with the silicon dioxide nano modified carrier into the middle of a tubular muffle furnace;

step (2.3), setting the temperature and time of the muffle furnace, carrying out temperature programming, and introducing nitrogen gas;

step (2.4) after the muffle furnace reaches the set temperature, closing the nitrogen, simultaneously introducing the petroleum waste heated to the preset temperature into the tubular muffle furnace, and starting timing to perform reaction;

closing the petroleum waste control pipe valve and the muffle furnace after the reaction is finished, and introducing nitrogen;

and (2.6) cooling the muffle furnace to room temperature under the condition of filling nitrogen, and taking out the quartz boat in the tube to obtain the silicon dioxide nano modified composite electrode with the surface attached with the graphene layer.

Further, the ratio of the amount of vinyltrimethoxysilane used in the step (1.1) to the amount of absolute ethyl alcohol is 1g:5 ml.

Further, the pH value is adjusted to 9-11 in the step (1.2).

Further, the reaction temperature of the step (1.3) is 38-42 ℃, the reaction time is 2-3h, and the reaction is carried out under the stirring condition.

Further, the temperature of the drying box in the step (1.4) is 110-120 ℃, and the drying time is 10-12 h.

Further, the nitrogen gas introduction rate in the step (2.3) and the step (2.5) is 150-200 mL/min.

Further, in the step (2.4), the temperature of the muffle furnace is set to be 900-.

Further, the reaction time of the step (2.4) is 35-40 min.

And (3) further, cooling the muffle furnace for 4-5 hours to room temperature in the step (2.6).

The invention has the beneficial effects that: the invention comprehensively adopts the traditional top-down method, improves the process, and has innovation and advancement. The invention discloses a preparation method of a thermal cracking graphene nano modified composite silicon dioxide nano modified electrode, which decomposes and recombines a carbon source on a silicon dioxide nano modified carrier by creating a high-temperature oxygen-free condition to form a graphene layer on the electrode. The graphene electrode prepared by the method has low resistance, long service life, good stability and stronger oxidation resistance and corrosion resistance; the electrode has sensitive reaction, and the preparation scheme is efficient and safe. Effectively solves the problems of uneconomic, unsafe, short service life, poor stability and the like of the electrode prepared by the prior art.

The electrode adopts high-inertia material silicon dioxide to carry out nano modification as a carrier, then uses waste containing carbon in petroleum processing as a raw material, adopts a thermal cracking method to prepare graphene, and compounds the graphene with the silicon dioxide nano modified material carrier after the graphene is modified, thereby forming the electrochemical working electrode with excellent conductivity and strong oxidation resistance.

Compared with the traditional method for producing graphene, the method avoids the multi-step synthesis method of chemical intercalation in the conventional micro-nano material processing. The graphene nanocomposite is synthesized by using low-price multi-carbon chain-containing waste in petroleum processing as a raw material through a thermal cracking reaction one-step method, and has the advantages of low raw material cost, high strong oxidation resistance, good stability and high SOD detection accuracy.

Detailed Description

The present invention will be described in further detail with reference to examples for the purpose of facilitating understanding and practice of the invention by those of ordinary skill in the art, and it is to be understood that the present invention has been described in the illustrative embodiments and is not to be construed as limited thereto.