Three-dimensional graphene / metal composite material, preparation method and application thereof

Abstract

This invention discloses a three-dimensional graphene / metal composite material, its preparation method, and its application. The preparation method includes: laser treatment of a benzoxazine compound to obtain three-dimensional graphene; and electroplating with a mixture containing acetate, an organic solvent, and water as the electroplating solution, using the three-dimensional graphene as the working electrode, and applying a current density of 0.1 mA / cm². 2 ~3mA / cm 2 Electroplating was performed under specific conditions to obtain a three-dimensional graphene / metal composite material. The three-dimensional graphene / metal composite material prepared by this invention retains the porous structure of three-dimensional graphene and has excellent electrical conductivity, showing great promise for applications in electrochemical sensors, catalysis, supercapacitors, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a three-dimensional graphene / metal composite material, its preparation method, and its application. Background Technology

[0002] Graphene, a highly promising two-dimensional nanomaterial, possesses excellent mechanical strength, electrical conductivity, and thermal conductivity, making it widely applicable across various fields. Two-dimensional graphene is the fundamental building block of other carbon materials; its stacked 3D porous electrodes exhibit high porosity, which helps increase the contact area between the carbon structure and the electrolyte, enhancing bilayer capacitance and pseudocapacitance effects, thereby promoting charge transfer. This leads to its wide application in supercapacitors, electrochemical sensors, catalysis, and other fields. Commonly used 3D graphene preparation methods include self-assembly and template methods. The resulting three-dimensional graphene structures generally depend on the choice of template or container, leading to complex preparation processes and poor conductivity.

[0003] Laser-induced graphene (LIG) uses resins such as polyimide and polybenzoxazine as precursors to prepare three-dimensional porous graphene frameworks in a one-step laser-induced process, showing promising industrial application prospects in catalytic electrodes, supercapacitors, and adsorption. However, this method can only be used to prepare multilayer graphene, and the conductivity and catalytic activity of the materials are difficult to meet the requirements of practical applications. To achieve high-performance applications, it is often combined with metals and metal oxides. In-situ doping with metal salts can achieve uniform dispersion of metals in LIG, but the morphology and content of the metals are often difficult to control. Electrochemical deposition on the LIG surface can better preserve the porous structure of LIG while obtaining porous composite materials with high conductivity and high catalytic activity. However, due to insufficient wettability between the electroplating solution and LIG, the electroplating solution cannot completely wet the LIG surface when electroplating in commonly used aqueous solutions, resulting in metal particles being unable to enter the internal pore structure of LIG. In addition, the metal particles deposited in aqueous solutions are large and easily block the pore structure of LIG, thus affecting subsequent performance (Composites Communications 32 (2022) 101187). Summary of the Invention

[0004] The main objective of this invention is to provide a three-dimensional graphene / metal composite material, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a method for preparing a three-dimensional graphene / metal composite material, comprising:

[0007] Three-dimensional graphene was prepared by laser treatment of benzoxazine compounds;

[0008] Furthermore, an electroplating solution comprising acetate, organic solvent, and water was used, with the three-dimensional graphene as the working electrode, and a current density of 0.1 mA / cm² was applied. 2 ~3mA / cm 2 Electroplating was performed under specific conditions to obtain a three-dimensional graphene / metal composite material.

[0009] The present invention also provides a three-dimensional graphene / metal composite material prepared by the aforementioned preparation method, wherein the three-dimensional graphene / metal composite material comprises three-dimensional graphene and nano-sized metal particles; the metal particles are loaded on the internal pores or external surface of the three-dimensional graphene.

[0010] This invention also provides the application of the aforementioned three-dimensional graphene / metal composite material in the preparation of electrochemical sensors or in the detection of glucose.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] (1) The electroplating solution of the present invention uses an organic solvent / water composite solvent, which can greatly enhance the conductivity of the solution, thereby improving the electroplating efficiency and avoiding the problem of long electroplating time when using pure organic solution. In addition, the combination of organic solvent and water reduces the surface energy of the solution and enhances the wettability of the electroplating solution with three-dimensional graphene, thereby enabling metal nanoparticles to be uniformly loaded on the surface of three-dimensional graphene.

[0013] (2) This invention uses three-dimensional graphene as a conductive framework. By controlling the concentration of the electroplating solution and the current density, the nano-sized metal particles are uniformly loaded on the graphene surface. While enhancing the conductivity and catalytic activity of the material, it has almost no impact on the structural integrity, porosity and material density of the three-dimensional structure. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram illustrating the preparation of a three-dimensional graphene / metal composite material in a typical embodiment of the present invention;

[0016] Figures 2a-2b This is a SEM image of the three-dimensional porous graphene prepared in Example 1 of this invention;

[0017] Figure 3This is the Raman spectrum of the three-dimensional porous graphene prepared in Example 1 of this invention;

[0018] Figure 4 This is a conductivity diagram of the electroplating solution in Embodiment 1 of the present invention;

[0019] Figures 5a-5b This is a SEM image of the three-dimensional graphene / metal composite material prepared in Example 1 of this invention;

[0020] Figures 6a-6b This is a SEM image of the three-dimensional graphene / metal composite material prepared in Example 3 of this invention;

[0021] Figure 7 This is the XRD pattern of the three-dimensional graphene / metal composite material prepared in Example 1 of this invention;

[0022] Figure 8 This is a CV diagram of the three-dimensional graphene / metal composite material prepared in Example 1 of this invention catalyzing the oxidation of glucose;

[0023] Figure 9 This is a graph showing the change of electrochemical current over time when the three-dimensional graphene / metal composite material prepared in Example 1 of this invention catalyzes the oxidation of glucose.

[0024] Figure 10 This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 1 of this invention;

[0025] Figure 11 This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 2 of this invention;

[0026] Figure 12 This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 3 of this invention;

[0027] Figures 13a-13b This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 4 of this invention;

[0028] Figure 14 This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 5 of this invention;

[0029] Figures 15a-15b This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 6 of this invention;

[0030] Figures 16a-16b This is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 7 of this invention;

[0031] Figures 17a-17bThis is a SEM image of the three-dimensional graphene / metal composite material prepared in Comparative Example 8 of this invention. Detailed Implementation

[0032] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0033] Specifically, as one aspect of the technical solution of this invention, a method for preparing a three-dimensional graphene / metal composite material includes:

[0034] Three-dimensional graphene was prepared by laser treatment of benzoxazine compounds;

[0035] Furthermore, an electroplating solution comprising acetate, organic solvent, and water was used, with the three-dimensional graphene as the working electrode, and a current density of 0.1 mA / cm² was applied. 2 ~3mA / cm 2 Electroplating was performed under specific conditions to obtain a three-dimensional graphene / metal composite material.

[0036] In some preferred embodiments, the benzoxazine compound comprises a benzoxazine monomer and / or a benzoxazine monomer derivative; the benzoxazine compound is a liquid material.

[0037] Furthermore, the benzoxazine compounds are fusible and soluble non-polymeric molecules.

[0038] Furthermore, the benzoxazine compound is a benzoxazine compound with high carbon-forming ability.

[0039] In some preferred embodiments, the preparation method includes: reacting a mixed reaction system containing a phenolic source, an amine source, paraformaldehyde and / or formaldehyde at 70-120°C for 4-8 hours to obtain the benzoxazine monomer.

[0040] Furthermore, the phenol source has a structure as shown in formula (I):

[0041]

[0042] R1, R2, R3, and R4 are each independently selected from any one of hydrogen atom, hydroxyl group, carboxyl group, nitro group, halogen, substituted or unsubstituted alkyl group, olefin group, ester group, alkoxy group, phenyl group, and naphthyl group.

[0043] Furthermore, the amine source has a structure as shown in formula (II):

[0044] H2N-R5

[0045] Equation (II)

[0046] R5 is selected from substituted or unsubstituted phenyl, furfuryl or naphthyl.

[0047] Furthermore, the molar ratio of the functional groups of the phenolic source, amine source and polyoxymethylene and / or formaldehyde is 1:0.5 to 2:1 to 5.

[0048] In some preferred embodiments, the preparation method includes reacting the benzoxazine monomer with any one of an acyl halide, an alcohol, or a haloalkane to obtain the benzoxazine monomer derivative.

[0049] Furthermore, the acyl halide has a structure as shown in formula (III):

[0050]

[0051] Wherein, X is selected from chlorine, bromine or iodine, and R6 is selected from substituted or unsubstituted alkyl, alkoxy, phenyl or naphthyl.

[0052] Furthermore, the alcohol or haloalkane has a structure as shown in formula (IV):

[0053] X-R7

[0054] Formula (IV)

[0055] Wherein, X is selected from hydroxyl, chlorine, bromine or iodine, and R7 is selected from substituted or unsubstituted alkyl, alkoxy, phenyl or naphthyl.

[0056] In some preferred embodiments, the laser light source used for the laser processing includes a CO2 laser with a laser power of 2.5W to 15W.

[0057] In some preferred embodiments, the laser processing uses a scanning speed of 6–40 cm / s and a Z-axis defocusing distance of 0–7 mm.

[0058] In some preferred embodiments, the three-dimensional graphene has a porous structure, and the pores contained in the three-dimensional graphene have a pore size of 5 to 20 μm.

[0059] In some preferred embodiments, the preparation method specifically includes: using a laser to perform laser patterning on benzoxazine compounds to obtain patterned three-dimensional graphene.

[0060] Furthermore, the patterned three-dimensional graphene contains electrode structures comprising any one or more of the following: straight lines, curves, polygons, circles, rings, and sectors.

[0061] In some preferred embodiments, the preparation method specifically includes: mixing an organic solvent and water uniformly at room temperature, then adding acetate and dissolving it by ultrasonication, followed by standing treatment, and separating the obtained supernatant as an electroplating solution.

[0062] In some preferred embodiments, the organic solvent includes any one or a combination of two or more of ethanol, acetonitrile, and acetone, but is not limited thereto.

[0063] In some preferred embodiments, the water is deionized water, but is not limited thereto.

[0064] In some preferred embodiments, the acetate includes any one or a combination of two or more of copper acetate (such as anhydrous copper acetate, copper acetate monohydrate), nickel acetate, ferric acetate, and cobalt acetate, and is not limited thereto.

[0065] In some preferred embodiments, the volume ratio of organic solvent to water in the electroplating solution is 1:0.2 to 1:4.

[0066] Furthermore, the volume ratio of organic solvent to water in the electroplating solution is 1:0.2 to 1:1.

[0067] In some preferred embodiments, the concentration of acetate in the electroplating solution is 0.05 g / 100 mL to 1 g / 100 mL.

[0068] Furthermore, the concentration of acetate in the electroplating solution is 0.05 g / 100 mL to 0.5 g / 100 mL.

[0069] In some preferred embodiments, the current density is 0.2 mA / cm². 2 ~2mA / cm 2 .

[0070] In some preferred embodiments, the preparation method specifically includes: using the three-dimensional graphene as the working electrode, a Cu sheet or graphite sheet electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode, followed by electroplating in the electroplating solution to obtain a three-dimensional graphene / metal composite material; wherein the area of ​​the auxiliary electrode is more than three times the area of ​​the working electrode.

[0071] In some preferred embodiments, the preparation method further includes washing and drying the obtained product after the electroplating process is completed.

[0072] Furthermore, acetonitrile and water are used for washing.

[0073] In some more specific embodiments, the preparation method of the three-dimensional graphene / metal composite material includes the following steps:

[0074] (1) A three-dimensional porous graphene conductive framework (i.e., the aforementioned three-dimensional graphene, denoted as LIG) was obtained by laser treatment of benzoxazine compounds. The laser source used for laser treatment was a CO2 laser with a laser power of 2.5W to 10W, a scanning speed of 6 to 30cm / s, and a Z-axis defocusing distance of 0 to 7mm.

[0075] (2) Prepare the electroplating solution using a mixture of organic solvent and water in a volume ratio of 1:0 to 1:1. Then add acetate to the mixture at a concentration of 0.05 g / 100 mL to 0.5 g / 100 mL and sonicate at room temperature for 5 minutes until completely dissolved. Let the electroplating solution stand at room temperature for 2 to 5 days and use the supernatant as the final electroplating solution.

[0076] (3) During electroplating, LIG ​​is used as the working electrode, Cu sheet or graphite electrode as the auxiliary electrode, and Ag / AgCl electrode as the reference electrode. The area of ​​the auxiliary electrode must be at least three times the area of ​​the working electrode. The electroplating current density is 0.2 mA / cm². 2 ~2mA / cm 2 The electroplating time is 0.5h to 3h.

[0077] (4) The electroplated LIG was rinsed with a large amount of acetonitrile and water, and then placed in a vacuum drying oven at 60°C for 1 hour to obtain a three-dimensional graphene / metal composite material.

[0078] Preferably, a laser is used to pattern benzoxazine compounds to obtain three-dimensional graphene with patterned conductive networks. The patterned graphene contains any one or more combinations of electrode structures such as straight lines, curves, polygons, circles, rings, and fan shapes.

[0079] Preferably, the organic solvent is any one or a combination of two or more of ethanol, acetonitrile, and acetone.

[0080] Preferably, the acetate is any one or a combination of two or more of copper acetate, nickel acetate, ferric acetate, and cobalt acetate.

[0081] In this invention, the solution used in the electroplating process is an acetate solution, and the solvent is an organic solvent / water composite solvent. This significantly enhances the conductivity of the solution, thereby improving electroplating efficiency and avoiding the long plating time problem encountered with pure organic solutions. Furthermore, the combination of the organic solvent and water lowers the surface energy of the solution, enhancing the wettability of the electroplating solution with LIG. This allows the metal nanoparticles to be uniformly loaded on the LIG surface with almost no impact on the porous structure inside the LIG. The resulting composite material retains the porous structure of LIG and possesses excellent conductivity, promising to play an important role in electrochemical sensors, catalysis, and supercapacitors.

[0082] Another aspect of the present invention provides a three-dimensional graphene / metal composite material prepared by the aforementioned preparation method, wherein the three-dimensional graphene / metal composite material comprises three-dimensional graphene and nano-sized metal particles; the metal particles are loaded on the internal pores or external surface of the three-dimensional graphene.

[0083] Furthermore, the particle size of the metal particles is 100–500 nm.

[0084] Furthermore, the content of metal particles in the three-dimensional graphene / metal composite material is 10-70 wt%.

[0085] Another aspect of the present invention provides the application of the aforementioned three-dimensional graphene / metal composite material in the preparation of electrochemical sensors or in the detection of glucose.

[0086] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0087] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0088] The electrochemical catalytic performance testing methods for the composite materials in the following examples are as follows:

[0089] Cyclic voltammetry (CV) curve testing: Electrochemical catalytic performance was tested in a 1M KOH solution with a glucose concentration of 1mM. The working electrode (LIG-Cu) had an area of ​​1.5 x 1 cm. 2 The counter electrode is a graphite sheet electrode (2×2cm). 2 The reference electrode was an Ag / AgCl electrode. The voltage scan range was 0–0.8 V, and the scan rate was 40 mV / s.

[0090] Chronocurrent response test: The test was conducted in a 1M KOH solution with stirring using a magnetic stirrer. The potential was controlled at 0.5V during the test, and timing began after the current stabilized. At fixed time points, a glucose aqueous solution of a certain concentration was added to the electrolyte using a pipette, and the current change was detected. All other test conditions were the same as for CV.

[0091] Example 1

[0092] Preparation of benzoxazine compounds:

[0093] 1.0 mol of propyl gallate, 2.0 mol of furfurylamine, and 5.0 mol of paraformaldehyde were reacted at 80 °C for 5 hours using dioxane as a solvent to obtain a pale yellow, transparent solution. Unreacted reactants were removed by washing with saturated sodium carbonate solution and water. Finally, the solvent was removed using a rotary evaporator to obtain the benzoxazine monomer product.

[0094]

[0095] Preparation of three-dimensional graphene / metal composite materials:

[0096] 1) In the control software of the laser engraving system (Universal, VLS 3.50), the scanning area was set to a rectangle (1.5 x 1 cm), the laser power to 7.5 W, the scanning speed to 19 cm / s, and the Z-axis distance to 3 mm. Based on these conditions, the benzoxazine monomer product was laser-processed to obtain a three-dimensional porous graphene structure (denoted as LIG). The SEM image of the prepared LIG is shown below. Figures 2a-2b As shown, the Raman spectrum is as follows: Figure 3 As shown;

[0097] 2) Prepare the electroplating solution using a mixture of acetonitrile and water at a volume ratio of 3:2. After thoroughly mixing the acetonitrile and water, add copper acetate monohydrate at a concentration of 0.15 g / 100 mL. Sonicate the solution until the copper acetate monohydrate is completely dissolved. Let the solution stand at room temperature for 72 hours; a small amount of precipitate will appear at the bottom. Collect the supernatant as the final electroplating solution. The conductivity of the electroplating solution with different acetonitrile to water volume ratios is shown in the figure below. Figure 4 As shown;

[0098] 3) The electroplating equipment used, such as Figure 1 As shown, LIG ​​is the working electrode (1.5×1cm), Cu sheet (5×5cm) is the counter electrode, and Ag / AgCl electrode is the reference electrode. The distance between the working electrode and the counter electrode is 5cm. Electroplating is performed at room temperature, and the area of ​​Cu sheet is 5 times the area of ​​LIG.

[0099] 4) Before electroplating, immerse the working electrode in the electroplating solution for 30 minutes to ensure the solution fully wets the electrode. Then, apply an electric current for electrodeposition at a current density of 1 mA / cm². 2 The deposition time was 2 hours. After electroplating, the LIG electrode was thoroughly rinsed with acetonitrile and water, and then vacuum dried at 60°C for 1 hour in a vacuum drying oven to obtain a three-dimensional graphene / metal composite material. The SEM image of the three-dimensional graphene / metal composite material is shown below. Figures 5a-5b As shown, the XRD pattern is as follows Figure 7 As shown.

[0100] The three-dimensional graphene / metal composite material prepared in this embodiment was subjected to electrochemical catalytic performance testing. The CV curve for catalytic oxidation of glucose is shown in the figure below. Figure 8 As shown in the figure; the change of electrochemical current over time during the catalytic oxidation of glucose is shown in the figure. Figure 9 As shown, the glucose detection sensitivity in 0.1M KOH solution is 11900 μA / (mM·cm). 2 The detection limit is 0.79 μM.

[0101] Example 2

[0102] Preparation of benzoxazine compounds:

[0103] 1.0 mol of catechol, 2.0 mol of aniline, and 5.0 mol of paraformaldehyde were reacted at 80 °C for 5 hours using dioxane as a solvent to obtain a yellow, transparent solution. Unreacted reactants were removed by washing with saturated sodium carbonate solution and water. Finally, the solvent was removed using a rotary evaporator to obtain the benzoxazine monomer product.

[0104]

[0105] Preparation of three-dimensional graphene / copper composite materials:

[0106] 1) The scanning area was set to a rectangle (1.5×1cm), the laser power to 7.5W, the scanning speed to 19cm / s, and the Z-axis distance to 3mm. Based on these conditions, a three-dimensional porous graphene structure (denoted as LIG) was obtained by laser processing of the benzoxazine monomer product.

[0107] 2) The electroplating solution is a mixture of ethanol and water, with a volume ratio of ethanol to water of 3:2. After mixing the ethanol and water thoroughly, add copper acetate monohydrate at a concentration of 0.15 g / 100 mL. Sonicate the solution until the copper acetate monohydrate is completely dissolved. Let the solution stand at room temperature for 72 hours. A small amount of precipitate will appear at the bottom of the solution; collect the supernatant, which is the final electroplating solution.

[0108] 3) The electroplating equipment used, such as Figure 1As shown, LIG ​​is the working electrode (1.5×1cm), Cu sheet (5×5cm) is the counter electrode, and Ag / AgCl electrode is the reference electrode. The distance between the working electrode and the counter electrode is 5cm. Electroplating is performed at room temperature, and the area of ​​Cu sheet is 10 times the area of ​​LIG.

[0109] 4) Before electroplating, immerse the working electrode in the electroplating solution for 30 minutes to ensure the solution fully wets the electrode. Then, apply an electric current for electrodeposition at a current density of 0.33 mA / cm². 2 The deposition time was 2 hours. After electroplating, the LIG electrode was thoroughly rinsed with acetonitrile and water, and then vacuum-dried at 60°C for 1 hour in a vacuum drying oven to obtain a three-dimensional graphene / copper composite material. In 0.1 MkOH solution, the glucose detection sensitivity was 2096 μA / (mM·cm⁻¹). 2 The detection limit is 0.86 μM.

[0110] Example 3

[0111] Preparation of benzoxazine compounds:

[0112] 1.0 mol pyrogallol, 2.0 mol aniline, and 5.0 mol paraformaldehyde were reacted in ethyl acetate at 70°C for 5 hours. After cooling to room temperature, a large amount of white powder precipitated. The product was washed with hot ethanol, filtered, and dried to obtain a light yellow powder.

[0113]

[0114] 1.0 mol of the pale yellow powder product was dissolved in chloroform, and 1.2 mol of triethylamine was added as an acid-binding agent. 1.2 mol of nonanoyl chloride was then slowly added dropwise to the above solution, and the reaction was carried out in an ice-water bath for 6 hours. The resulting solution was washed with 1.0 mol of hydrochloric acid aqueous solution and deionized water, respectively. Finally, the solvent was removed by rotation to obtain a yellow, transparent nonanoyl chloride-modified benzoxazine monomer, i.e., a benzoxazine compound.

[0115]

[0116] Preparation of three-dimensional graphene / copper composite materials:

[0117] 1) The scanning area was set to a rectangle (1.5×1cm), the laser power to 7.5W, the scanning speed to 19cm / s, and the Z-axis distance to 3mm. Based on these conditions, a three-dimensional porous graphene structure (denoted as LIG) was obtained by laser processing of benzoxazine compounds.

[0118] 2) The electroplating solution is a mixture of ethanol and water, with a volume ratio of ethanol to water of 3:2. After mixing the ethanol and water thoroughly, add copper acetate monohydrate at a concentration of 0.15 g / 100 mL. Sonicate the solution until the copper acetate monohydrate is completely dissolved. Let the solution stand at room temperature for 72 hours. A small amount of precipitate will appear at the bottom of the solution; collect the supernatant, which is the final electroplating solution.

[0119] 3) The electroplating equipment used, such as Figure 1 As shown, LIG ​​is the working electrode (1.5×1cm), Cu sheet (5×5cm) is the counter electrode, and Ag / AgCl electrode is the reference electrode. The distance between the working electrode and the counter electrode is 5cm. Electroplating is performed at room temperature, and the area of ​​Cu sheet is 10 times the area of ​​LIG.

[0120] 4) Before electroplating, immerse the working electrode in the electroplating solution for 30 minutes to ensure the solution fully wets the electrode. Then, apply an electric current for electrodeposition at a current density of 0.67 mA / cm². 2 The deposition time was 2 hours. After electroplating, the LIG electrode was thoroughly rinsed with acetonitrile and water, and then vacuum dried at 60°C for 1 hour in a vacuum drying oven to obtain a three-dimensional graphene / metal composite material. The SEM image of the three-dimensional graphene / metal composite material is shown below. Figures 6a-6b As shown. In 0.1M KOH solution, the glucose detection sensitivity is 4261 μA / (mM·cm). 2 The detection limit is 0.91 μM.

[0121] Comparative Example 1

[0122] In Comparative Example 1, copper was electroplated onto the LIG surface using a commonly used CuSO4 aqueous solution, with a CuSO4 concentration of 0.16 M, an H2SO4 concentration of 0.1 M, and a current density of 10 mA / cm². 2 The electroplating time was 2 hours. The remaining experimental methods and conditions in this comparative example were the same as in Example 1.

[0123] Electroplating in an aqueous CuSO4 solution resulted in a very fast deposition rate and a dense coating due to the excellent conductivity of the solution. However, the relatively large metal particles and the limited wettability of the aqueous solution to LIG resulted in only a uniform metal layer covering the LIG surface. This blocked the pore structure of the LIG, preventing the full utilization of its internal structure. (SEM image attached.) Figure 10 Because copper is in bulk and isolates the solution from the internal LIG, it has virtually no catalytic function. In 0.1 M KOH solution, the glucose detection sensitivity is 25.3 μA / (mM·cm⁻¹). 2 The detection limit is 12.6 μM.

[0124] Comparative Example 2

[0125] In Comparative Example 2, copper was electroplated onto the LIG surface using a commonly used aqueous solution of Cu(CH3COO)2, with a Cu(CH3COO)2 concentration of 0.15 g / 100 mL and a current density of 1 mA / cm². 2 The electroplating time was 2 hours. The remaining experimental methods and conditions in this embodiment were the same as those in the above embodiments.

[0126] Electroplating was performed in an aqueous solution of Cu(CH3COO)2. This solution exhibited good conductivity and a fast deposition rate. However, the resulting metal particles were relatively large, and the aqueous solution had limited wettability on the LIG. Consequently, the coating was uniformly distributed on the LIG surface, clogging the LIG's pore structure and preventing the full utilization of its internal pore structure. (SEM images are shown below.) Figure 11 In 0.1M KOH solution, the detection sensitivity for glucose is 253 μA / (mM·cm). 2 The detection limit is 5.7 μM.

[0127] Comparative Example 3

[0128] The method is the same as in Example 1, except that the water in the electroplating solution is replaced with acetonitrile. Electroplating is performed in a pure acetonitrile solution. The copper acetate concentration is 0.15 g / 100 mL, and the current density is 1 mA / cm². The microstructure of the material after 2 hours of electroplating is as follows. Figure 12 As shown, due to the low conductivity of the solution, the copper deposition rate was low; after 2 hours of electroplating, only a small amount of copper particles were deposited on the LIG surface. In 0.1 MkOH solution, the glucose detection sensitivity was 472 μA / (mM·cm⁻¹). 2 The minimum detection limit is 3.6 μM. To further increase the deposition of copper particles, the electroplating time needs to be extended (more than 10 hours).

[0129] Comparative Example 4

[0130] The method is the same as in Example 1, except that the volume ratio of acetonitrile to water in the electroplating solution is 1:10. The concentration of copper acetate is 0.15 g / 100 mL, and the current density is 1 mA / cm². 2 The microstructure of the material after 2 hours of electroplating is as follows: Figures 13a-13b As shown, due to the large volume of water in the solution and its high conductivity (~450 μS / cm), the copper deposition rate during electroplating is very fast. After 2 hours of electroplating, a large amount of copper is deposited on the LIG surface, with almost no copper particles inside. In 0.1 MkOH solution, the glucose detection sensitivity is 57 μA / (mM·cm). 2 The detection limit is 9.4 μM.

[0131] Comparative Example 5

[0132] The method is the same as in Example 1, except that the concentration of copper acetate in the electroplating solution is 0.05 g / 100 mL. The current density is 1 mA / cm², and the microstructure of the material after 2 hours of electroplating is as follows. Figure 14 As shown, due to the low concentration of copper acetate in the solution, the copper deposition rate was low, and only a small amount of copper particles were deposited on the LIG surface after 2 hours of electroplating (e.g., Figure 14 As shown in the figure, the copper particles on the surface are relatively loose. In 0.1M KOH solution, the glucose detection sensitivity is 159 μA / (mM·cm⁻¹). 2 The detection limit is 5.4 μM.

[0133] Comparative Example 6

[0134] The method is the same as in Example 1, except that the concentration of copper acetate in the electroplating solution is 1.5 g / 100 mL. The current density is 1 mA / cm², and the microstructure of the material after 2 hours of electroplating is as follows. Figures 15a-15b As shown, after 2 hours of electroplating, a layer of copper particles is deposited on the LIG surface (e.g. Figures 15a-15b As shown in the image, the particle diameter is 0.5–1 μm. The cross-sectional image shows a small amount of Cu particles generated inside the LIG pores. In 0.1 M KOH solution, the glucose detection sensitivity is 6457 μA / (mM·cm⁻¹). 2 The detection limit is 2.4 μM.

[0135] Comparative Example 7

[0136] The method is the same as in Example 1, except that the current density is 0.05 mA / cm². 2 The electrolyte concentration was 0.15 g / 100 mL. The microstructure of the material after electroplating for 2 hours is as follows. Figures 16a-16b As shown, due to the low concentration of copper acetate in the solution, the copper deposition rate was low. After 2 hours of electroplating, only a very small amount of copper particles were deposited on the LIG surface, and the particle distribution was uneven (e.g., ...). Figures 16a-16b As shown in the cross-sectional image, no copper particles were found inside the LIG pores. In 0.1 M KOH solution, the glucose detection sensitivity was 59 μA / (mM·cm⁻¹). 2 The detection limit is 15.6 μM.

[0137] Comparative Example 8

[0138] The method is the same as in Example 1, except that the current density is 5 mA / cm². 2 The electrolyte concentration was 0.15 g / 100 mL. The microstructure of the material after electroplating for 2 hours is as follows. Figures 17a-17b As shown, due to the high deposition current density, the copper deposition rate is very fast. After 2 hours of electroplating, a large number of copper particles are deposited on the LIG surface (e.g., Figures 17a-17bAs shown in the diagram, the cross-sectional view reveals almost no particle deposition inside. Furthermore, the copper particles deposited at this current density exhibit a loose, porous, dendritic structure, possibly due to the hydrogen evolution reaction occurring at the cathode at the higher current density, generating a large amount of hydrogen gas. In 0.1 MkOH solution, the glucose detection sensitivity is 568 μA / (mM·cm). 2 The detection limit is 4.1 μM.

[0139] Example 4

[0140] 1) In the control software of the laser engraving system (Universal, VLS 3.50), the scanning area was set to a rectangle (1.5×1cm), the laser power to 2.5W, the scanning speed to 6cm / s, and the Z-axis distance to 0mm. Based on the above conditions, benzoxazine compounds (the benzoxazine compounds in Example 1) were laser-processed to obtain a three-dimensional porous graphene structure (denoted as LIG).

[0141] 2) Prepare the electroplating solution using a mixture of acetone and water at a volume ratio of 10:1. After thoroughly mixing the acetone and water, add nickel acetate at a concentration of 0.05 g / 100 mL. Sonicate the solution until the nickel acetate is completely dissolved.

[0142] 3) The electroplating equipment used, such as Figure 1 As shown, LIG ​​is the working electrode (1.5×1cm), graphite electrode (5×5cm) is the counter electrode, and Ag / AgCl electrode is the reference electrode. The distance between the working electrode and the counter electrode is 5cm. Electroplating is performed at room temperature, and the area of ​​the Cu sheet is 5 times the area of ​​the LIG.

[0143] 4) Before electroplating, immerse the working electrode in the electroplating solution for 30 minutes to ensure the solution fully wets the electrode. Then, apply an electric current for electrodeposition at a current density of 1 mA / cm². 2 The deposition time was 2 hours. After electroplating, the LIG electrode was thoroughly rinsed with acetonitrile and water, and then vacuum dried at 60°C for 1 hour in a vacuum drying oven to obtain a three-dimensional graphene / metal composite material.

[0144] Example 5

[0145] 1) In the control software of the laser engraving system (Universal, VLS 3.50), the scanning area was set to a rectangle (1.5 × 1 cm), the laser power to 15 W, the scanning speed to 40 cm / s, and the Z-axis distance to 7 mm. Based on the above conditions, benzoxazine compounds (the benzoxazine compounds in Example 1) were laser-processed to obtain a three-dimensional porous graphene structure (denoted as LIG).

[0146] 2) Prepare the electroplating solution using a mixture of acetonitrile and water at a volume ratio of 1:4. After thoroughly mixing the acetonitrile and water, add ferric acetate at a concentration of 1 g / 100 mL. Sonicate the solution until the ferric acetate is completely dissolved.

[0147] 3) The electroplating equipment used, such as Figure 1 As shown, LIG ​​is the working electrode (1.5×1cm), Cu sheet (5×5cm) is the counter electrode, and Ag / AgCl electrode is the reference electrode. The distance between the working electrode and the counter electrode is 5cm. Electroplating is performed at room temperature, and the area of ​​Cu sheet is 5 times the area of ​​LIG.

[0148] 4) Before electroplating, immerse the working electrode in the electroplating solution for 30 minutes to ensure the solution fully wets the electrode. Then, apply an electric current for electrodeposition at a current density of 1 mA / cm². 2 The deposition time was 2 hours. After electroplating, the LIG electrode was thoroughly rinsed with acetonitrile and water, and then vacuum dried at 60°C for 1 hour in a vacuum drying oven to obtain a three-dimensional graphene / metal composite material.

[0149] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0150] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing a three-dimensional graphene / metal composite material, characterized in that, include: Three-dimensional graphene was prepared by laser treatment of benzoxazine compounds; wherein the three-dimensional graphene has a porous structure and the pore size of the pores contained in the three-dimensional graphene is 5~20 μm. Furthermore, an electroplating solution comprising acetate, organic solvent, and water was used, with the three-dimensional graphene as the working electrode, and a current density of 0.1 mA / cm² was applied. 2 ~3 mA / cm 2 Electroplating is performed under the following conditions to obtain a three-dimensional graphene / metal composite material; wherein, the volume ratio of organic solvent to water in the electroplating solution is 1:0.2 to 1:4; the concentration of acetate in the electroplating solution is 0.05g / 100mL to 1g / 100mL; the acetate includes any one or a combination of two of anhydrous copper acetate and copper acetate monohydrate; The three-dimensional graphene / metal composite material includes three-dimensional graphene and nano-sized metal particles; the metal particles are loaded on the internal pores or external surface of the three-dimensional graphene; the particle size of the metal particles is 100~500 nm; the three-dimensional graphene / metal composite material includes a three-dimensional graphene / copper composite material; the content of metal particles in the three-dimensional graphene / metal composite material is 10~70 wt%.

2. The preparation method according to claim 1, characterized in that: The benzoxazine compounds include benzoxazine monomers and / or benzoxazine monomer derivatives; the benzoxazine compounds are liquid materials.

3. The preparation method according to claim 1, characterized in that: The laser source used in the laser processing includes a CO2 laser with a laser power of 2.5W to 15W.

4. The preparation method according to claim 1, characterized in that: The laser processing uses a scanning speed of 6~40cm / s and a Z-axis defocusing distance of 0~7mm.

5. The preparation method according to claim 1, characterized in that, Specifically, it includes: Patterned three-dimensional graphene was prepared by laser patterning of benzoxazine compounds. The patterned three-dimensional graphene contains electrode structures that include any one or more of the following: straight lines, curves, polygons, circles, rings, and sectors.

6. The preparation method according to claim 1, characterized in that, Specifically, it includes: The organic solvent and water were mixed evenly at room temperature, then acetate was added and dissolved by ultrasonication. After standing, the supernatant was separated and used as the electroplating solution.

7. The preparation method according to claim 1, characterized in that: The organic solvent includes any one or a combination of two or more of ethanol, acetonitrile, and acetone.

8. The preparation method according to claim 1, characterized in that: The water is deionized water.

9. The preparation method according to claim 1, characterized in that: The volume ratio of organic solvent to water in the electroplating solution is 1:0.2 to 1:

1.

10. The preparation method according to claim 1, characterized in that: The concentration of acetate in the electroplating solution is 0.05 g / 100 mL to 0.5 g / 100 mL.

11. The preparation method according to claim 1, characterized in that: The current density is 0.2 mA / cm². 2 ~2 mA / cm 2 .

12. The preparation method according to claim 1, characterized in that, Specifically, it includes: Using the three-dimensional graphene as the working electrode, a Cu sheet or graphite electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode, electroplating is then performed in the electroplating solution to obtain a three-dimensional graphene / metal composite material; wherein the area of ​​the auxiliary electrode is more than three times the area of ​​the working electrode.

13. The preparation method according to claim 1, characterized in that, Also includes: After the electroplating process is completed, the obtained product is washed and dried.

14. A three-dimensional graphene / metal composite material prepared by any one of claims 1-13.

15. The application of the three-dimensional graphene / metal composite material of claim 14 in the preparation of electrochemical sensors or in the detection of glucose.

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