Layered C60 crystalline network material as well as preparation method and application thereof

Abstract

The invention discloses a layered C60 crystalline network material as well as a preparation method and application thereof, and belongs to the technical field of preparation of layered C60 network materials. The preparation method of the layered C60 crystalline network material comprises the following steps: placing a magnesium raw material on one side of a quartz tube, placing C60 powder on the other side of the quartz tube, roasting in a vacuum atmosphere, and crystallizing to generate Mg4C60 crystals; the preparation method comprises the following steps: uniformly mixing an aqueous solution of inorganic acid with a polar solution of salicylic acid to obtain a mixed solution, and adding Mg4C60 crystals into the mixed solution for etching and coordination reaction to obtain the layered C60 crystalline network material. Based on the convection type chemical vapor transport method, Mg4C60 crystals can be synthesized in a high-quality and large-batch mode, the yield can reach the gram level, and the layered C60 crystalline network material of a multi-layer structure can be prepared according to the method.

Description

Technical Field

[0001] This invention relates to layered C 60 In the field of network material preparation technology, more specifically, it relates to a layered C 60 Crystalline network materials, their preparation methods, and applications. Background Technology

[0002] Carbon is one of the most abundant elements on Earth, playing a vital role in everything from the origin of life to the development of modern industry. Due to its ability to form various types of hybrid chemical bonds (sp, sp², and sp³), carbon possesses a unique capacity to combine with a wide range of elements, resulting in a vast array of carbon-based compounds. Carbon exists in nature in three distinct allotropes: graphite, diamond, and amorphous carbon, whose chemical and physical properties have been extensively studied and understood. Currently, the synthesis of novel carbon allotropes is attracting significant attention, with discoveries such as carbon nanotubes, disordered carbon, graphite, graphynylene, and fullerenes. These new forms of carbon have triggered substantial advances in scientific and technological research, driving the development of numerous derivatives, devices, and applications. Recently, Hou et al. and Meirzadeh et al. achieved carbon synthesis by mimicking the hexagonal structure of graphene. 60 Periodic covalent bonds of molecules were used to successfully prepare monolayer and bilayer C4 molecules, respectively. 60 Network. And for multi-layered C... 60 Methods for preparing these networks remain poorly understood. This research gap limits the scope of research on C... 60 A deeper understanding of the structure and properties of materials at the three-dimensional scale.

[0003] The entire production process includes two steps: Mg intercalation into C 60 Network synthesis (i.e., Mg4C) 60 ) and subsequent Mg removal. This two-dimensional C 60 Networked nanosheets exhibit unexpected semiconductor behavior and enhanced heat transfer properties, as well as a variety of potential applications, such as batteries and catalysis. To advance the development and application of these materials, a key step lies in the efficient, large-scale synthesis of Mg4C. 60 Crystals and subsequent Mg removal.

[0004] To prepare Mg4C 60 Crystals, existing methods involve using C 60 The mixture of Mg powder and Mg evaporates simultaneously in the high-temperature zone and crystallizes in the low-temperature zone. Figure 1 (a) In the reaction process, metallic Mg acts as a charge donor to stimulate C. 60 The molecules are covalently bonded. However, at the same temperature, Mg and C... 60 The significant difference in thermal volatility between them essentially hinders Mg4C 60The ideal stoichiometric vapor for crystallization. Therefore, simultaneous vaporization within the same temperature range is not advisable. To date, this traditional chemical vapor transport method suffers from low yields and small crystal quantities, making it unsuitable for widespread application. Furthermore, most C... 60 The combination of raw materials and Mg involves side reactions, leading to C 60 The utilization rate is low. Summary of the Invention

[0005] To address the above problems, this invention provides a layered C 60 Crystalline network materials, their preparation methods, and applications: Based on the convective chemical vapor transport method of this invention, Mg4C can be synthesized in high-quality, large-scale quantities. 60 Crystals can be produced in gram quantities, and layered C crystals with multi-layered structures can be prepared according to the method of this invention. 60 Crystalline network materials.

[0006] The first objective of this invention is to provide a layered C 60 The preparation method of crystalline network materials includes the following steps: The magnesium raw material is placed on one side of the quartz tube, and C... 60 The powder was placed on the other side of the quartz tube and calcined under a vacuum atmosphere, allowing the magnesium raw material and C to react. 60 Volatilization, magnesium and C 60 First, the components are vaporized to produce steam, then the steam is transported by convection diffusion, and crystallization produces Mg4C. 60 Crystal.

[0007] An aqueous solution of an inorganic acid is mixed thoroughly with a polar solution of salicylic acid to obtain a mixed solution. Mg4C 60 Crystals are added to a mixed solution for etching and coordination reactions. During the etching and coordination reactions, Mg4C... 60 After acid etching, the Mg ions released from the crystal are removed by coordination with salicylate ions, yielding layered C. 60 Crystalline network materials.

[0008] During etching and coordination reactions, the inorganic acid can be hydrochloric acid, sulfuric acid, or nitric acid. The removal of Mg is achieved by using the inorganic acid in combination with salicylic acid. If other coordination acids are used, they will not dissolve under the conditions of this system and subsequent preparation cannot be carried out.

[0009] In a preferred embodiment of the present invention, magnesium raw material and C 60 The mass ratio of the powder is 1:2~2.5.

[0010] In a preferred embodiment of the present invention, the volatilization temperature of the magnesium raw material is 600℃~620℃; C 60 The evaporation temperature of the powder is 500℃~520℃.

[0011] In a preferred embodiment of the present invention, Mg4C 60 The ratio of crystals to mixed solution is 2 mg to 2.5 mg: 1 ml.

[0012] In the mixed solution, the molar ratio of inorganic acid to salicylic acid is 1:1 to 1.5.

[0013] In a preferred embodiment of the present invention, the inorganic acid is nitric acid and the polar solvent is methylpyrrolidone.

[0014] In a preferred embodiment of the present invention, the etching and coordination reactions are carried out at room temperature for 72-78 hours.

[0015] In a preferred embodiment of the present invention, the calcination time is 20h to 30h.

[0016] In a preferred embodiment of the present invention, the magnesium raw material is a magnesium block. This is because Mg and SiO2 in the quartz tube will undergo a side reaction. Using a magnesium block reduces the direct contact between magnesium and the quartz tube, thereby reducing the side reaction.

[0017] A second objective of this invention is to provide a layered C obtained by the above-described preparation method. 60 Crystalline network materials.

[0018] A third objective of this invention is to provide the above-mentioned layered C 60 Application of crystalline network materials in electrochemical energy storage.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a convective gas-phase transport method, which involves evaporating a Mg source and a C source on both sides of a vacuum quartz tube. 60 Powder, Mg4C was produced in one step 60 Gram-scale production of crystals. Traditional chemical vapor transport methods involve reacting Mg with C... 60 After mixing, the mixture undergoes gas-phase volatilization on one side, while Mg and C... 60 The volatile properties are significantly different, and they are inherently unsuitable for volatilization under the same chemical environment. Therefore, traditional preparation methods can only produce small amounts and small particles of Mg4C. 60 Crystal. According to the preparation method of this invention, Mg4C... 60 The production volume of crystals is far greater than that of traditional chemical vapor transport methods, and also with Mg4C 60 Using crystals as precursors, a combination of acid etching and coordination strategy—specifically, the use of a mixed solution of inorganic acid and salicylic acid—was employed to controllably remove magnesium, yielding three-dimensional layered C4 crystals. 60 network. Attached Figure Description

[0020] Figure 1To synthesize Mg4C 60 A schematic diagram of the crystal, where a represents a synthesis method reported in the prior art; b represents the preparation of Mg4C based on convective gas-phase transport in this invention. 60 A schematic diagram of the crystal formation process.

[0021] Figure 2 The images show the vacuum quartz tube before and after synthesis, where a is before synthesis and b is after synthesis.

[0022] Figure 3 Mg4C synthesized in Example 1 60 Crystal structure and optical photographs of the crystal, where a is the crystal structure along the b-axis, b is the crystal structure along the a-axis, and c is Mg₄C with a scale bar of 1 cm. 60 Crystal optical image, d is Mg4C with a scale bar of 20 μm. 60 Crystallographic optical microscope image.

[0023] Figure 4 To prepare Mg4C 60 Characterization data of the crystal. Where 'a' represents Mg₄C with a scale bar of 200 μm. 60 Scanning electron microscope image; b is Mg4C with a scale bar of 100 μm. 60 Scanning electron microscope image; c is the elemental mapping distribution, including elements C, Mg, and O; d is the prepared Mg4C. 60 Energy spectrum curve of the crystal; e represents Mg4C 60 Powder XRD pattern of crystal; f represents Mg4C 60 Raman spectral data of the crystal.

[0024] Figure 5 Mg4C 60 Crystal-derived layered C 60 Characterization data of crystalline network materials. Where 'a' represents layered C with a scale bar of 200 μm. 60 Scanning electron microscope image of crystalline network material; b is layered C with a scale bar of 20 μm. 60 Scanning electron microscope (SEM) image of the crystalline network material; c is the mapping distribution of element C; d is the mapping distribution of element Mg; e is the prepared layered C 60 Energy spectroscopy curves of crystalline network materials; f represents layered C 60 Powder XRD curves of crystalline network materials.

[0025] Figure 6 For layered C 60 Performance data of Na / Cl2 cells with crystalline networks. Where 'a' represents the assembled Na / Cl2 cell at 100 mA g. -1 The following is a description of deep charge and discharge; b is a layered C 60 Crystalline network and original C60 Powder performance comparison; c is layered C 60 Crystalline network and primitive C 60 Rate performance of powder. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that in the preparation of Mg4C 60 When crystallizing, the C used 60 The powder is a single-molecule crystal, while the final product is a layered C 60 The crystalline network material is a polymer.

[0028] Example 1 Step 1: Weigh out approximately 60mg of magnesium and 120mg of C. 60 The powder is in a quartz tube, such as Figure 2 As shown, after vacuum sealing, the tube is transferred to a multi-zone tube furnace, where C is heated under a vacuum atmosphere. 60 Powder in 10 o The temperature was increased to 510℃ at a heating rate of C / min, and the magnesium raw material was heated at 10... o After heating at a rate of C / min to 600℃ and calcining for 24 hours, a large amount of black Mg4C was found inside the quartz tube. 60 Crystals, such as Figure 2 As shown, each quartz tube contains no less than 50 mg of crystals.

[0029] Step 2: After the reaction is complete, unreacted C is still observed. 60 Molecular crystals exist, can be recycled and reused, and the C after reuse... 60 Molecular crystals can still grow high-quality Mg4C. 60 Crystal.

[0030] Step 3: Prepare 50 ml of 2M nitric acid aqueous solution and 50 ml of 2M salicylic acid methylpyrrolidone solution, mix them to obtain a mixed solution.

[0031] Step 4: Add 200mg of Mg4C 60 The crystals were placed in a mixed solution and reacted at room temperature for 3 days.

[0032] Step 5: Wash the reaction product three times with deionized water, then three times with anhydrous ethanol. Finally, place the product in a vacuum drying oven and dry it at 60°C for 12 hours to obtain layered C. 60 Crystalline network materials.

[0033] Example 2 Step 1: Weigh out approximately 60mg of magnesium and 150mg of C. 60 The powder was placed in a quartz tube, vacuum sealed, and then transferred to a multi-zone tube furnace. Under a vacuum atmosphere, C... 60 Powder in 10 o The temperature was increased to 500℃ at a heating rate of C / min, and the magnesium raw material was heated at 10... o After heating at a rate of C / min to 610℃ and calcining for 30 hours, a large amount of black Mg4C was found inside the quartz tube. 60 Crystal.

[0034] Step 2: After the reaction is complete, unreacted C is still observed. 60 Molecular crystals exist, can be recycled and reused, and the C after reuse... 60 Molecular crystals can still grow high-quality Mg4C. 60 Crystal.

[0035] Step 3: Prepare 50 ml of 2M sulfuric acid aqueous solution and 50 ml of 3M salicylic acid N,N-dimethylformamide solution, mix them to obtain a mixed solution.

[0036] Step 4: Add 250mg of Mg4C 60 The crystals were placed in a mixed solution and reacted at room temperature for 78 hours.

[0037] Step 5: Wash the reaction product three times with deionized water, then three times with anhydrous ethanol. Finally, place the product in a vacuum drying oven and dry it at 60°C for 12 hours to obtain layered C. 60 Crystalline network materials.

[0038] Example 3 Step 1: Weigh out approximately 60 mg of magnesium and 140 mg of C. 60 The powder was placed in a quartz tube, vacuum sealed, and then transferred to a multi-zone tube furnace. Under a vacuum atmosphere, C... 60 Powder in 10 o The temperature was increased to 520℃ at a heating rate of C / min, and the magnesium raw material was subjected to a heating rate of 10... o After heating at a rate of C / min to 620℃ and calcining for 20 hours, a large amount of black Mg4C was found inside the quartz tube. 60 Crystal.

[0039] Step 2: After the reaction is complete, unreacted C is still observed. 60 Molecular crystals exist, can be recycled and reused, and the C after reuse... 60 Molecular crystals can still grow high-quality Mg4C. 60 Crystal.

[0040] Step 3: Prepare 50 ml of 2M hydrochloric acid aqueous solution and 50 ml of 2.5M salicylic acid methylpyrrolidone solution, mix them to obtain a mixed solution.

[0041] Step 4: Add 230mg of Mg4C 60 The crystals were placed in a mixed solution and reacted at room temperature for 76 hours.

[0042] Step 5: Wash the reaction product three times with deionized water, then three times with anhydrous ethanol. Finally, place the product in a vacuum drying oven and dry it at 60°C for 12 hours to obtain layered C. 60 Crystalline network materials.

[0043] Gram-sized Mg4C can be prepared according to the preparation methods of Examples 1 to 3. 60 The crystals exhibit near 100% Mg removal efficiency in subsequent steps. Example 1 is used as an example to illustrate the preparation of Mg4C. 60 Crystalline and layered C 60 The crystalline network material was characterized.

[0044] Mg4C prepared in Example 1 60 The crystal underwent a series of structural characterizations. For example... Figure 3 a and b in Mg4C 60 Crystal structure, in this polymer sheet, C 60 Unit cells are interconnected along the b-axis via [2+2] cycloaddition reactions, while individual C-C bonds connect units along the a-axis. In a single unit cell, each C... 60 The molecule is bonded to four Mg counterions through a mechanism intermediate between ionic and covalent bonds. For example... Figure 3 As shown in c, Mg4C is synthesized based on magnesium blocks. 60 The crystals can be prepared in large quantities at the gram level and exhibit a good hexagonal morphology under an optical microscope. Figure 3 The structure in d) conforms to its theoretical hexagonal bond structure.

[0045] A series of spectroscopic tests and electron microscopy characterizations were used to test the prepared Mg4C 60 Crystals. For example... Figure 4 As shown in a, Mg4C 60 The crystals can reach the scale of hundreds of micrometers. Furthermore, as shown in Figure b, the crystals exhibit a well-defined hexagonal morphology, consistent with theoretical values ​​(C).60 The hexagonal bond configuration corresponds to this. Elemental analysis of a local area of ​​the crystal revealed a uniform distribution of Mg and C. Figure 4 c). Corresponding energy spectrum curve test ( Figure 4 In the formula d), the atomic percentages of Mg and C are 6.35 at% and 90.65 at%, respectively, which are close to its theoretical chemical formula Mg₄C₂. 60 The stoichiometric ratio was determined. The observed presence of oxygen was due to surface oxidation. Powder XRD analysis was also performed to verify the crystallinity and phase purity of the crystals. Before powder XRD analysis, the crystals were thoroughly ground for at least 5 minutes to ensure homogeneity. Figure 4 As shown in Figure e, the diffraction peaks are consistent with the simulation data, and no additional impurities were found. The diffraction peak at 10.39 belongs to the (200) crystal plane, indicating that Mg4C 60 The interlayer spacing is 8.47 Å. In Raman spectroscopy, such as Figure 4 As shown in f, Mg4C 60 At 913, 978 and 1429 cm -1 The vibration peak at that location belongs to C 60 The bridging bond between subunits, and the pentagonal stretching mode (Ag) 2 This is consistent with previously reported results. These tests all demonstrate the successful preparation of Mg4C using the convection vapor deposition method. 60 Crystal.

[0046] The layered C prepared in Example 1 60 A series of structural characterizations were performed on the crystalline network material. For example... Figure 5 As shown in a and b, after the reaction of salicylic acid and nitric acid mixed solution, C 60 The crystalline network material exhibits a distinct layered structure. This structural transformation is primarily attributed to the complete removal of Mg during the reaction. Corresponding elemental analysis and energy dispersive spectroscopy (EDS) curves indicate that ( Figure 5 The resulting layered C (c, d, and e) 60 The crystalline network material showed a high carbon content (93.57%), but no magnesium content was detected, confirming the presence of layered carbon. 60 The pure carbon characteristics of the crystalline network material were observed. Powder XRD analysis was also performed. Figure 5 The derived peaks at 8.94° and 19.30° in f are respectively layered C 60 The (200) and (400) crystal planes at the crystalline network material. The regular appearance of these two diffraction peaks indicates the prepared layered C 60 The material exhibits a highly ordered crystal structure with a calculated interlayer spacing of approximately 0.99 nm. These results demonstrate that layered C can be successfully prepared through a controllable Mg removal process.60 Crystalline network materials.

[0047] Prepared C 60 The crystalline network material exhibits typical layered structure characteristics, with an interlayer spacing measured to be 0.99 nm. 60 The molecules, as structural building blocks, possess excellent redox activity, and this layered structure can provide storage space for alkali metal ions. The structural characteristics of this material are similar to graphite, suggesting potential applications in metal-ion batteries. Simultaneously, the layered C... 60 C in crystalline network materials 60 Structural units can combine with metals, such as Pt and Pd, and can serve as supports for metal catalysts. 60 It is an excellent charge donor and acceptor, and can promote charge transfer in catalytic reactions. Therefore, this layered C 60 Crystalline network materials have potential applications in electrochemical energy storage and electrocatalysis.

[0048] To further verify layered C 60 The application potential of crystalline network materials, this invention will utilize layered C 60 Crystalline networks are applied in the field of Na / Cl2 batteries. For example... Figure 6 As shown in a, at 100 mA g -1 Under deep charge and discharge conditions, its capacity can reach up to 1120 mAh g. -1 At the same time, their coulombic efficiencies are also close to 100%. (This is in contrast to the molecular C...) 60 In comparison, layered C 60 Crystalline networks have higher capacity ( Figure 6 (b) in the text. And, from... Figure 6 As can be seen from 'c', layered C 60 Crystalline networks also exhibit good rate performance.

[0049] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0050] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A layered C 60 method of making a crystalline network material, characterized in that, The method comprises the following steps: A magnesium raw material is placed on one side of a quartz tube, and C 60 powder is placed on the other side, and firing is performed under a vacuum atmosphere, so that the magnesium raw material and C 60 are volatilized, and the magnesium and C 60 are vaporized separately to produce vapor, and the vapor is diffusively transported by convection to produce Mg4C 60 crystals; The aqueous solution of inorganic acid is mixed with the polar solution of salicylic acid to obtain a mixed solution, and Mg4C 60 The crystal is added to the mixed solution to perform etching and coordination reaction. During the etching and coordination reaction, Mg4C 60 After the Mg in the crystal is etched by the acid, the released Mg ions are removed by coordination with salicylate to obtain layered C 60 crystalline network material.

2. The layered C 60 Method for the preparation of a crystalline network material, characterized in that, Magnesium raw material and C 60 The mass ratio of the powder is 1:2-2.

5.

3. The layered C 60 Method for the preparation of a crystalline network material, characterized in that, The volatilization temperature of the magnesium raw material is 600°C to 620°C; C 60 The volatilization temperature of the powder is 500°C to 520°C.

4. The layered C 60 Method for the preparation of a crystalline network material, characterized in that, Mg4C 60 The ratio of the crystal and the mixed solution was 2 mg - 2.5 mg: 1 ml; The molar ratio of the inorganic acid to the salicylic acid in the mixed solution is 1:1-1.

5.

5. The layered C 60 Method for the preparation of a crystalline network material, characterized in that, The inorganic acid is nitric acid, and the polar solution is methylpyrrolidone.

6. The layered C 60 Method for the preparation of a crystalline network material, characterized in that, The etching and coordination reaction are carried out at room temperature for 72-78 hours.

7. The layered C 60 Method for the preparation of a crystalline network material, characterized in that, The calcination time is 20-30 hours.

8. A layered CxHyNz material prepared according to the method of any one of claims 1 to 7. 60 crystalline network material.

9. A layered C 60 Use of crystalline state network materials in electrochemical energy storage.

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