Method for preparing two-dimensional carbon film by gallium-based alloy room temperature phase transition reducing carbon oxide

Abstract

The application discloses a method for preparing a two-dimensional carbon film by reducing carbon oxides through phase transition of a gallium-based alloy at room temperature, and comprises the following steps: step S1, adding mixed metal particles containing metallic gallium into a sealed container and sealing the container; step S2, removing air in the container and replacing it with high-purity CO or CO2 gas; step S3, continuously stirring or oscillating; step S4, converting the mixed metal particles containing metallic gallium into a liquid phase at room temperature; during the liquid phase conversion of the metal particles, the CO or CO2 gas is reduced to carbon material and covers the surface of the liquid metal; and step S5, peeling off the two-dimensional carbon film, thereby obtaining the two-dimensional carbon film. The method can directly convert CO or CO2 gas into a two-dimensional carbon film with excellent performance at room temperature, can solve the environmental problem, and can realize simple preparation of the two-dimensional carbon film, so the method has a wide application prospect.

Description

Technical Field

[0001] This invention relates to a negative carbon technology, specifically to a method for preparing two-dimensional carbon thin films by room temperature phase change reduction of carbon oxides using gallium-based alloys. Background Technology

[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.

[0003] Greenhouse gas emissions and global warming have become significant common problems, with carbon dioxide (CO2) being one of the most prevalent and widely distributed greenhouse gases. Negative CO2 emission technologies and functional applications are effective strategies for stabilizing the climate, ensuring energy supply, and reducing fossil fuel use. Converting CO2 into solid products or value-added chemicals allows it to be reused as fuel or used as important raw materials for chemical and electronic devices. Therefore, the ability to reverse-convert CO2 into carbon-containing functional materials with lower energy consumption has become an emerging research focus in related fields. As the largest air pollutant emitted, CO can be oxidized into CO2 through the oxidation of H₂O radicals, and effective methods for its control urgently need to be developed.

[0004] Two-dimensional carbon thin films possess excellent electrical, thermal, and mechanical properties, and have broad application prospects in cutting-edge fields such as flexible electronics and all-carbon circuits. Currently, the main methods for preparing two-dimensional carbon thin films include thermal decomposition of silicon carbide, exfoliation, oriented epiphytic methods, and chemical vapor deposition (CVD). The most commonly used and readily available method is chemical vapor deposition (CVD). However, CVD requires high temperature and high pressure conditions, and also needs to utilize various energy sources such as heating, plasma excitation, or light radiation, making the preparation process relatively complex.

[0005] Liquid metals, typically gallium-based low-melting-point alloys, are novel functional materials with unique physical and chemical behaviors. They possess characteristics such as safety and non-toxicity, high boiling point, high reflectivity, low electrical resistance, high flexibility, fluidity, and self-healing, and remain liquid at room temperature. These properties enable them to overcome many traditional technological bottlenecks and find wide application in numerous fields. In particular, room-temperature liquid metals spontaneously and instantaneously oxidize on their surfaces in environments containing trace amounts of oxygen, forming a thin layer of metal oxides approximately 1-3 nm thick, thereby altering their surface properties. The surface of room-temperature liquid metals is highly sensitive to foreign matter, and its surface structure and properties are largely dependent on the external environment. Based on this, gallium-based alloys exhibit excellent surface chemical activity after the liquid phase transition, providing a good platform and opportunity for the decomposition and functionalization of oxygen-containing carbon dioxide molecules. Summary of the Invention

[0006] The purpose of this invention is to address the problems of large-scale emissions of polluting gases CO and CO2 and the harsh production conditions of two-dimensional carbon thin films by providing a method for preparing two-dimensional carbon thin films by room temperature phase change reduction of carbon oxides with gallium-based alloys. This method can reduce CO and CO2 at room temperature and simultaneously generate carbon and gallium oxides with two-dimensional carbon nanostructures.

[0007] The technical solution of the present invention is as follows:

[0008] A method for preparing two-dimensional carbon thin films by room temperature phase transition reduction of carbon oxide with gallium-based alloys includes the following steps:

[0009] Step S1: Add gallium-containing mixed metal particles to the container and seal it;

[0010] Step S2: Remove the air from the container and replace it with high-purity CO or CO2 gas (99.99% purity);

[0011] Step S3: Stir continuously at 25-200℃; metals that can melt into a liquid state at 25-200℃ are considered to be liquid metals.

[0012] Step S4: Gallium-containing mixed metal particles are transformed into a liquid phase, and CO or CO2 gas is reduced to a two-dimensional carbon film that covers the surface of the liquid metal.

[0013] Step S5: After the gallium-containing mixed metal particles have completely melted, i.e., after the reaction is complete, the liquid metal and the two-dimensional carbon film are separated using conventional solid-liquid separation methods to obtain the two-dimensional carbon film. For example, this can be used for filtration or to extract the liquid metal using a syringe.

[0014] According to a preferred embodiment, the gallium-containing mixed metal particles include gallium metal particles and particles of one or more of indium, tin, bismuth, germanium, nickel, and silicon.

[0015] According to a preferred embodiment, in step S1, the diameter of the gallium-containing mixed metal particles is 1.0-5.0 mm. Within this particle diameter range, the melting rate of the particles is suitable, ensuring the reduction effect. Below this particle diameter range, the particles are difficult to prepare, resulting in higher costs; above this particle diameter range, the melting rate of the particles is too slow, leading to poor reduction effects.

[0016] According to a preferred embodiment, the gallium, indium, tin, bismuth, germanium, nickel, and silicon particles are high-purity metals with a purity of 99.9%.

[0017] According to a preferred embodiment, the mass ratio of gallium in the gallium-containing mixed metal particles is 30-95%, and gallium-based alloys exceeding this ratio will not be able to remain liquid at room temperature.

[0018] Compared with existing technologies, the advantages of this invention are:

[0019] 1. A method for preparing two-dimensional carbon thin films by room temperature phase change reduction of carbon oxides using gallium-based alloys. The gallium-containing mixed metal particles of this application utilize their high surface activity during the continuous melting and mixing process to form a liquid metal, enabling them to spontaneously decompose CO or CO2 gas at room temperature and generate two-dimensional carbon thin films and gallium oxide. The operation steps are simple, the reaction conditions are mild and easy to achieve, and two-dimensional carbon thin films can be prepared in the next step at room temperature. Only a simple separation step is needed to obtain pure two-dimensional carbon thin films. This method not only realizes the decomposition and functional transformation of atmospheric pollutants CO and CO2, but also achieves the simple preparation of high-performance two-dimensional carbon thin films.

[0020] 2. This patent has timely and systematically studied and guided the research on the synthesis strategies, surface activity, and carbon dioxide decomposition applications of room temperature liquid metals, providing new approaches for multiple fields such as energy, environment, chemical industry, electronics, and nanomaterials, and also providing new ideas and foundations for the special functional applications of room temperature liquid metals. Attached Figure Description

[0021] Figure 1 A flowchart for the room-temperature phase transition reduction of carbon oxides by gallium-based alloys to prepare two-dimensional carbon thin films.

[0022] Figure 2 This is a graph showing the analytical data of the solid product from Example 1;

[0023] Figure 3 This is a graph showing the analytical data of the solid product in Example 2. Detailed Implementation

[0024] The features and performance of the present invention will be further described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the methods mentioned in this application are all conventional methods in the art; and unless otherwise specified, the experimental materials used in this application are all commercially available.

[0025] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0026] Example 1: Method for preparing two-dimensional carbon thin films by room temperature phase transition reduction of CO2 with gallium-based alloys

[0027] The steps are as follows:

[0028] Step S1: Add 20g of gallium-containing mixed metal particles to a 50ml glass reaction flask, and then seal it with a sealing cap;

[0029] The gallium-containing mixed metal particles include gallium metal particles and indium metal particles, with a mass fraction of 75.5% for gallium metal particles and 24.5% for indium metal particles. After the two metal particles are mixed, gallium-based liquid metal can be gradually generated at room temperature.

[0030] Step S2: Use a multi-channel gas controller to remove air from the reaction flask and replace it with high-purity CO2 gas (99.9% purity);

[0031] Step S3: Stir continuously using a magnetic stirrer at room temperature. Stirring causes the mixed metal particles to continuously mix and melt to generate gallium-based liquid metal, and continuously exposes the more active surface of the gallium-based liquid metal, which spontaneously reacts with CO2 gas to form a black shell. At the same time, the black shell on the surface of the gallium-based liquid metal is continuously peeled off to restore the surface activity of the gallium-based liquid metal.

[0032] Step S4: Gallium-containing mixed metal particles are transformed into gallium-based liquid metal under stirring at room temperature, and CO2 gas is reduced to a two-dimensional carbon film that covers the surface of the gallium-based liquid metal.

[0033] Step S5: After the gallium-containing mixed metal particles have completely melted, use a syringe to extract the gallium-based liquid metal to obtain a two-dimensional carbon thin film.

[0034] like Figure 2 The figure shown is a graph of data analyzed from the solid products after the reaction. Figure 2 (a) shows the Raman scattering pattern of the products after the reaction of gallium-based liquid metal with carbon dioxide, exhibiting obvious C(D) and C(G) scattering peaks in Ga2O3 and carbon materials. This confirms that gallium-based liquid metal can directly decompose carbon dioxide, mainly forming Ga2O3 and two-dimensional carbon thin films after decomposition.

[0035] like Figure 2 As shown in (b), XPS spectral analysis and fitting were performed on the product stripped after the reaction of gallium-based liquid metal with carbon dioxide. The results show that the XPS spectrum can be fitted into four subpeaks at 287.39 eV, 285.02 eV, 286.53 eV, 289.07 eV, and 291.87 eV, corresponding to C=C, CC, CO, C=O, and π-π* satellite bond peaks, respectively. This indicates that carbon materials mainly composed of C=C and CC bonds are formed during carbon dioxide decomposition, while CO and C=O bonds are adsorbed simultaneously. This further confirms that gallium-based liquid metal (eGaIn) can directly decompose carbon dioxide and reverse its formation to form a two-dimensional carbon film.

[0036] like Figure 2(ce) shows the microstructure and elemental distribution of the products after the reaction of gallium-based liquid metal with carbon dioxide. The results show that the reduced carbon and Ga2O3 cover the surface of the liquid metal to form a core-shell structure. The shell layer has obvious distribution of Ga, O and C elements, but the distribution of In element is less. This indicates that during the reduction process, the Ga element on the surface of the liquid metal reacts with carbon oxide. The role of In is mainly to promote the rapid liquid phase transformation of alloy particles at room temperature.

[0037] Example 2: Method for preparing two-dimensional carbon thin films by room temperature phase transition reduction of CO using gallium-based alloys

[0038] The steps are as follows:

[0039] Step S1: Add 20g of gallium-containing mixed metal particles to a 50ml glass reaction flask, and then seal it with a sealing cap;

[0040] The gallium-containing mixed metal particles include gallium metal particles and indium metal particles, with a mass fraction of 75.5% for gallium metal particles and 24.5% for indium metal particles. After the two metal particles are mixed, gallium-based liquid metal can be gradually generated at room temperature.

[0041] Step S2: Use a multi-channel gas controller to remove air from the reaction flask and replace it with high-purity CO gas (99.9% purity);

[0042] Step S3: Stir continuously using a magnetic stirrer at room temperature. Stirring causes the mixed metal particles to continuously mix and melt to generate gallium-based liquid metal, and continuously exposes the more active surface of the gallium-based liquid metal, which spontaneously reacts with CO gas to form a black shell. At the same time, the black shell on the surface of the gallium-based liquid metal is continuously peeled off to restore the surface activity of the gallium-based liquid metal.

[0043] Step S4: Gallium-containing mixed metal particles are transformed into gallium-based liquid metal under stirring at room temperature, and CO gas is reduced to a two-dimensional carbon film that covers the surface of the gallium-based liquid metal.

[0044] Step S5: After the gallium-containing mixed metal particles have completely melted, use a syringe to draw out the gallium-based liquid metal to obtain a two-dimensional carbon thin film.

[0045] like Figure 3 The figure shown is a graph of data analyzed from the solid products after the reaction. Figure 3 (a) shows the Raman scattering pattern of the products after the reaction of gallium-based liquid metal with CO, exhibiting obvious C(D) and C(G) scattering peaks in Ga2O3 and carbon materials. This confirms that gallium-based liquid metal can directly decompose carbon monoxide, mainly forming Ga2O3 and two-dimensional carbon thin films after decomposition.

[0046] like Figure 3(b) shows the XRD analysis of the stripped products after the reaction. The product of the reaction between gallium-based liquid metal and carbon monoxide exhibits a diffraction peak of Ga2O3 (311). In addition, diffraction bulges appear at the C (111) and C (416) positions. This confirms that gallium-based liquid metal can directly decompose carbon monoxide, and the decomposition mainly forms Ga2O3 and two-dimensional carbon films.

[0047] Figure 3 (c) and Figure 3 (d) shows the XPS spectrum of the product stripped from gallium-based liquid metal after reaction with carbon monoxide. The results indicate that Ga is mainly present as Ga in the stripped mixed product. 3+ In exists in its oxidized form, and also in small amounts of metallic gallium. In is mainly present as In. 3+ It exists in the oxidized form, as well as indium metal. This is mainly because after gallium reacts with carbon monoxide on the surface of gallium-based liquid metal (eGaIn), a mixed shell of Ga2O3 and two-dimensional carbon thin film is formed, and a small amount of liquid metal also adheres when the shell is peeled off.

[0048] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for preparing two-dimensional carbon thin films by room temperature phase transition reduction of carbon oxides with gallium-based alloys, characterized in that, Includes the following steps: Step S1: Add gallium-containing mixed metal particles to the container and seal it; Step S2: Remove the air from the container and replace it with CO or CO2 gas with a purity of 99.99%; Step S3: Continue stirring or shaking; Step S4: Gallium-containing mixed metal particles are transformed into a liquid phase, and CO or CO2 gas is reduced to a two-dimensional carbon film that covers the surface of the liquid metal. Step S5: Separate the liquid metal and the two-dimensional carbon film to obtain the two-dimensional carbon film; In step S1, the gallium-containing mixed metal particles include gallium metal particles and indium metal particles; The mass ratio of gallium in the gallium-containing mixed metal particles is 30-95%.

2. The method for preparing two-dimensional carbon thin films by room temperature phase transition reduction of carbon oxide with gallium-based alloys according to claim 1, characterized in that, In step S1, the diameter of the gallium-containing mixed metal particles is 1.0-5.0 mm.

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