In-situ growth graphene / MOF composite microrod and preparation method thereof
Graphene and MOFs were compounded by in-situ growth method to prepare graphene/MOF composite microrods, which solved the insufficient performance problems of graphene and MOFs in practical applications, and achieved efficient preparation of materials and multifunctional expansion.
Patent Information
- Application Number
- CN202510309400.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-17
- Publication Date
- 2025-06-24
Smart Images
Figure CN120192541A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of graphene composite materials, and particularly relates to an in-situ grown graphene / MOF composite micro-rod and a preparation method thereof. Background Art
[0002] Due to its excellent electrical, mechanical and thermal properties, graphene has become a research focus in the field of materials science. However, graphene often faces problems such as agglomeration and sheet stacking in practical applications, significantly limiting the full play of its properties. Metal-organic frameworks (MOFs) are a class of materials with highly ordered pore structures and tunable chemical properties, and have attracted much attention due to their potential in fields such as gas storage, catalysis and separation. However, the relatively low conductivity and stability of MOFs themselves limit their practical application scope. Summary of the Invention
[0003] The purpose of the present invention is to propose an in-situ grown graphene / MOF composite micro-rod and a preparation method thereof in view of the above deficiencies of the prior art.
[0004] The first object of the present invention is to provide a preparation method of an in-situ grown graphene / MOF composite micro-rod, comprising the following steps:
[0005] Step S1: Inject a mixed slurry composed of graphene oxide and an organic small molecule ligand into a rotating turntable containing a metal salt solution coagulation bath through a syringe to obtain a composite gel micro-rod suspension;
[0006] Step S2: Perform a hydrothermal reaction on the composite gel micro-rod suspension, and then naturally cool it to room temperature;
[0007] Step S3: Filter the micro-rod slurry cooled in Step S2, wash it with a volatile organic solvent to obtain a graphene / MOF composite micro-rod mixed slurry, and then dry and grind it to obtain a graphene / MOF composite micro-rod.
[0008] Further, in Step S1, the mixed slurry is obtained by liquid-liquid mixing of a graphene oxide solution and an organic small molecule ligand dispersion and ultrasonic vibration dispersion; wherein the solvent in the graphene oxide solution is one of water, N,N-dimethylformamide, and N-methyl-2-pyrrolidone, and the concentration is 5-45 mg / ml.
[0009] Further, the organic ligand in the organic small molecule ligand dispersion is one of 2-methylimidazole, 2,6-naphthalenedicarboxylic acid, terephthalic acid, and 2,5-dihydroxyterephthalic acid, the solvent is one of water, ethanol, methanol, and N,N-dimethylformamide, and the concentration is 0.01-45 mol / L.
[0010] Furthermore, the molar ratio of graphene oxide to the organic small molecule ligand is 1:3 - 12.
[0011] Furthermore, in step S1, the metal salt in the metal salt solution coagulation bath is one of Zn 2+ , Co 2+ , Ni 2+ , Fe 3+ , Cu 2+ , Zr 4+ , and the corresponding solvent is one of water, ethanol, methanol, and N, N - dimethylformamide or a mixture of two of them.
[0012] Furthermore, in step S1, the syringe is a screw - threaded syringe with a volume of 5 - 100 ml, the matching needle is a 100 - 200 mm long needle, the inner diameter of the needle is between 50 - 550 μm, and the injection speed is controlled between 0.1 - 3.0 ml / min.
[0013] Furthermore, in step S2, a hydrothermal reaction is carried out at 60 - 150 °C for 3 - 24 hours, and then it is naturally cooled to room temperature.
[0014] Furthermore, the volatile organic solvent is acetone, and it is filtered and washed with a 200 - 1000 - mesh filter screen, and the filtration and washing are repeated 2 - 4 times.
[0015] Furthermore, in step S3, drying is to transfer it to a polytetrafluoroethylene container and dry it in an oven at 60 - 120 °C; grinding is to quickly grind it with a micro - grinder for 5 - 120 seconds, and then the corresponding graphene / MOF composite micro - rods can be obtained;
[0016] The graphene / MOF composite micro - rod mixed slurry is a suspension obtained after filtration and washing with acetone and adding 10 - 150 ml of acetone.
[0017] The second object of the present invention is to provide an in - situ grown graphene / MOF composite micro - rod prepared by the above - mentioned preparation method.
[0018] By compounding graphene with MOFs, the present invention can effectively make up for the deficiencies of the two and form a new composite material - graphene / MOF composite micro - rods. This composite structure can not only effectively inhibit the agglomeration and accumulation of graphene, but also utilize the porous structure and chemical tunability of MOFs to endow the material with more extensive functions and application potential.
[0019] The preparation of graphene / MOF composite micro-rods has important scientific significance and broad application prospects. First, the diversity of MOFs enables the structure and properties of this composite material to be highly adjustable. By selecting different metal ions and organic ligands, MOFs with specific pore sizes, surface properties, and functions can be designed. By adjusting the concentrations of small molecule ligands and metal salts, the preparation of RGO / MOF composite micro-rods with different loadings can be achieved, thereby realizing the precise regulation of the properties of the composite material. Second, the introduction of graphene can significantly improve the conductivity and mechanical strength of MOFs, broadening their application scope in electronic devices, sensors, and energy storage devices. In addition, the unique "scallion roll"-like axially oriented close-packed structure of the graphene-based micro-rod framework not only promotes the uniform dispersion and stable binding of MOFs but also endows the material with excellent ionic conductivity. This graphene / MOF composite micro-rod material shows great application potential in fields such as catalyst carriers, gas separation, and energy storage materials.
[0020] The RGO / MOF composite micro-rods prepared in this invention are obtained through an in-situ growth reaction by combining the wet spinning, hydrothermal reaction, and solvent exchange processes, achieving the growth of MOFs on two-dimensional graphene nanosheets while co-assembling with graphene on the one-dimensional framework of the micro-rods, realizing the uniform and firm loading of MOFs in the space of graphene-based micro-rods, and greatly enriching the types of graphene-based one-dimensional assembled materials. Description of the Drawings
[0021] Figure 1 SEM photograph of RGO / ZIF-8 composite micro-rods;
[0022] Figure 2 X-ray diffraction pattern of RGO / ZIF-8 composite micro-rods;
[0023] Figure 3 N2 adsorption-desorption isotherm and pore size distribution curve graph of pure RGO micro-rods, pure ZIF-8 particles, and RGO / ZIF-8 composite micro-rods;
[0024] Figure 4 Impedance spectrum graph of lithium metal half-cells assembled with pure ZIF-8 and RGO / ZIF-8 composite electrodes;
[0025] Figure 5 Coulombic efficiency graph of pure ZIF-8, pure RGO, and RGO / ZIF-8 composite electrodes;
[0026] Figure 6 Galvanostatic charge-discharge curves of pure ZIF-8 and RGO / ZIF-8 composite electrodes;
[0027] Figure 7 SEM photograph of RGO / ZIF-67 composite micro-rods;
[0028] Figure 8 This is the X-ray diffraction pattern of RGO / ZIF-67 composite microrods;
[0029] Figure 9 This is a scanning electron microscope photo of RGO / NiFe MOFs composite microrods;
[0030] Figure 10 This is the X-ray diffraction pattern of RGO / NiFe MOFs composite microrods. DETAILED DESCRIPTION
[0031] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0032] Example 1
[0033] The in-situ growth RGO / MOF composite microrod preparation process, here is the RGO / ZIF-8 composite microrod preparation, the specific process is as follows:
[0034] First, prepare the graphene oxide / 2-methylimidazole composite slurry, weigh 11.9g of 2-methylimidazole with an electronic balance, add it to a test tube containing 10ml of deionized water, and ultrasonically vibrate until it is completely dissolved. Subsequently, slowly pour the solution into 100ml of graphene oxide solution with a concentration of 11.9mg / ml, and ultrasonically vibrate again to ensure uniform mixing to prepare a composite slurry for use. At the same time, weigh 5.39g of Zn(NO3)2.6H2O, dissolve it in a mixed solution consisting of 200ml of deionized water and 300ml of ethanol to prepare a coagulation bath solution.
[0035] Place a crystallization dish with a diameter of 180 mm on an automatic horizontal turntable, add about 100 ml of coagulation bath solution, and adjust the rotation speed to 110 - 160 rpm. Use a plastic syringe to extract about 15 ml of pre - mixed and homogeneous graphene oxide / 2 - methylimidazole composite slurry. After switching to a long injection needle with a length of 120 - 180 mm, adjust the needle direction to be tangent to the rotation direction of the turntable. The inner diameter of the needle is between 50 - 350 μm, and control the injection speed at 0.5 - 2 ml / min. Under the combined action of shear force, ion cross - linking and coordination, graphene oxide and 2 - methylimidazole small molecule ligands cross - link and coordinate with zinc ions in the coagulation bath in the solution to self - assemble into composite gel micro - rods. Transfer the obtained mixed solution of gel micro - rods to a 500 - ml autoclave and carry out a hydrothermal reaction at 85 - 150 °C for 12 hours. After the reaction is completed, cool it naturally to room temperature. Filter the cooled micro - rods with gauze and rinse them repeatedly with acetone. Then redisperse them in a small amount of acetone and dry them in an oven at 80 - 120 °C. After drying, use a micro - grinder to grind them quickly for 10 - 60 seconds to obtain RGO / ZIF - 8 composite micro - rod powder.
[0036] As Figure 1 shown, the scanning electron microscope (SEM) results indicate that the prepared RGO / MOF composite material is overall in the shape of micro - rods, with a diameter range of 30 - 100 μm, and has a typical flaky wrinkled structure of graphene (RGO) on the surface. MOF particles are evenly distributed on the RGO micro - rod framework, with uniform particle size (about 50 - 300 nm) and no obvious agglomeration phenomenon. This indicates that the tight composite of RGO and MOF has been successfully achieved by the in - situ growth method.
[0037] The corresponding X - ray powder diffraction (XRD) pattern ( Figure 2 ) shows that the diffraction peaks of the RGO / MOF composite material are highly consistent with the simulated standard diffraction peaks of ZIF - 8, further confirming that the MOF particles in the composite material are ZIF - 8 particles with high crystallinity.
[0038] In addition, the N adsorption - desorption isotherm and pore size distribution curve ( Figure 3 ) show that the specific surface area of the RGO / ZIF - 8 composite micro - rod is significantly higher than that of the pure RGO micro - rod and slightly lower than that of the pure ZIF - 8. This indicates that the in - situ introduction of MOF effectively inhibits the agglomeration and stacking of graphene, and at the same time realizes the precise regulation of pore size.
[0039] Impedance test ( Figure 4) showed that the internal resistance of the RGO / ZIF-8 microrod-based composite electrode was significantly lower than that of the pure ZIF-8-based electrode, indicating that the graphene microrod framework structure constructed an excellent electron transport network, significantly reduced the interface resistance and charge transfer impedance, thereby greatly improving the electrode conductivity and improving the overall electrochemical performance.
[0040] like Figure 5 As shown, the RGO / ZIF-8 microrod-based composite electrode exhibits higher and more stable coulombic efficiency compared to the pure RGO electrode and the pure ZIF-8 electrode. This indicates that the composite material has higher charge transfer efficiency and better cycle stability during the charge and discharge process. The high conductivity of RGO and the porous structure of ZIF-8 work synergistically to provide a stable channel for ion transport while maintaining the integrity of the electrode structure, significantly reducing the energy loss in the electrochemical reaction.
[0041] In addition, the cycle performance test ( Figure 6 ) showed that the specific capacity of the RGO / ZIF-8 microrod-based composite electrode was significantly higher than that of the pure ZIF-8 electrode and remained stable after more than 10 cycles. This shows that the composite material not only has a high energy storage capacity, but also exhibits excellent cycle stability. The conductive network of RGO synergizes with the high specific surface area and porous properties of ZIF-8, enabling the composite microrods to efficiently store and release lithium ions while avoiding electrode structure collapse or active material shedding, further revealing the significant structural advantages and electrochemical performance advantages of RGO / ZIF-8 composite microrods in energy storage devices.
[0042] Example 2
[0043] Here is the preparation of RGO / ZIF-67 composite microrods. The specific process is as follows:
[0044] First, prepare the graphene oxide / 2-methylimidazole composite slurry, weigh 0.66g of 2-methylimidazole with an electronic balance, add it to a test tube containing 3ml of deionized water, and ultrasonically vibrate until it is completely dissolved. Subsequently, slowly pour the solution into 20ml of 6.2mg / ml graphene oxide solution, and ultrasonically vibrate again to ensure uniform mixing to prepare a composite slurry for use. At the same time, weigh 0.55g of Co(NO3)2.6H2O, dissolve it in a mixture of 200ml of deionized water and 300ml of ethanol to prepare a coagulation bath solution.
[0045] Place a crystallization dish with a diameter of 150 mm on an automatic horizontal turntable, add about 50 ml of coagulation bath solution, and adjust the rotation speed to 130 - 150 rpm. Use a plastic syringe to draw about 10 ml of pre - mixed and homogeneous graphene oxide / 2 - methylimidazole composite slurry. After switching to a long injection needle with a length of 120 - 180 mm, adjust the needle direction to be tangent to the rotation direction of the turntable. The inner diameter of the needle is between 100 - 250 μm, and control the injection speed at 0.5 - 1.5 ml / min. Under the combined action of shear force, ion cross - linking, and coordination, graphene oxide and 2 - methylimidazole small - molecule ligands cross - link and coordinate with cobalt ions in the coagulation bath in the solution to self - assemble into composite gel micro - rods. Transfer the obtained mixture of gel micro - rods to a 200 - ml autoclave and carry out a hydrothermal reaction at 90 °C for 12 hours. After the reaction is completed, cool it naturally to room temperature. Filter the cooled micro - rods with gauze, rinse them repeatedly with acetone, then redisperse them in a small amount of acetone and dry them in an oven at 80 - 120 °C. After drying, use a micro - grinder to grind quickly for 10 - 60 seconds to obtain RGO / ZIF - 67 composite micro - rod powder.
[0046] Figure 7 Figure 4 is the scanning electron microscope (SEM) photograph of RGO / ZIF - 67 composite micro - rods. Figure 7 It can be seen that the results of scanning electron microscopy (SEM) show that the prepared RGO / MOF composite material is overall in the shape of micro - rods, with a diameter range of 5 - 15 μm, and has a typical flaky wrinkled structure of graphene (RGO) on the surface. MOF particles are evenly distributed on the RGO micro - rod framework, with uniform particle size (about 50 - 350 nm) and no obvious agglomeration phenomenon. This indicates that the tight composite of RGO and MOF has been successfully achieved by the in - situ growth method.
[0047] Figure 8 Figure 5 is the X - ray diffraction pattern of RGO / ZIF - 67 composite micro - rods. Figure 8 It can be seen that the diffraction peaks of the RGO / MOF composite material are highly consistent with the simulated standard diffraction peaks of ZIF - 67, further confirming that the MOF particles in the composite material are highly crystalline ZIF - 67 nanoparticles.
[0048] Example 3
[0049] Here is the preparation of RGO / NiFe MOFs composite micro - rods, and the specific process is as follows:
[0050] First, prepare the graphene oxide / 1,4-naphthalene dicarboxylic acid composite slurry, weigh 0.5g of 1,4-naphthalene dicarboxylic acid with an electronic balance, add it to a test tube containing 4ml of N, N-dimethylformamide (DMF), and ultrasonically vibrate until it is completely dissolved. Subsequently, slowly pour the solution into 15ml of 7.1mg / ml graphene oxide solution, and ultrasonically vibrate again to ensure uniform mixing to prepare a composite slurry for use. At the same time, weigh 0.1g of Fe(NO3)3.9H2O and 0.4g of Ni(Ac)2, dissolve them in a mixture of 37.5ml of deionized water and 37.5ml of ethanol to prepare a coagulation bath solution.
[0051] Place a 180mm diameter crystallization dish on an automatic horizontal turntable, add about 50ml of coagulation bath solution, and adjust the speed to 100-120rpm. Use a plastic syringe to extract about 10ml of pre-mixed graphene oxide / 2-methylimidazole composite slurry, switch to a 120-180mm long injection needle, adjust the needle direction to be tangent to the direction of rotation of the turntable, the inner diameter of the needle is between 150-200μm, and the injection speed is controlled at 1.0-1.5ml / min. Under the combined action of shear force, ionic crosslinking and coordination, graphene oxide and 1,4-naphthalene dicarboxylic acid small molecule ligands crosslink and coordinate self-assemble with metal ions in the coagulation bath in the solution to form composite gel microrods. The resulting gel microrod mixture was transferred to a 200ml reactor and subjected to hydrothermal reaction at 80℃ for 12 hours. After the reaction was completed, it was naturally cooled to room temperature. The cooled microrods were filtered with gauze, rinsed repeatedly with acetone, and then redispersed in a small amount of acetone and dried in an oven at 80-120° C. After drying, the RGO / NiFe MOFs composite microrod powder was obtained by rapid grinding with a micro grinder for 10-60 seconds.
[0052] Figure 9 This is a scanning electron microscope photo of RGO / NiFe MOFs composite microrods. Figure 9 It can be seen that the MOF particles in the prepared RGO / MOF composite microrod material present a uniform nanosphere morphology without obvious agglomeration, with a diameter range of 400-500nm, and the sheet-like wrinkled graphene (RGO) uniformly wraps the MOF nanoparticles. This shows that the close compound of RGO and MOF was successfully achieved through the in-situ growth method.
[0053] Figure 10 is the X-ray diffraction pattern of RGO / NiFe MOFs composite microrods. Figure 10 It can be seen that the diffraction peaks of the RGO / MOF composite material coincide with those of the standard NiFe MOFs, further confirming that the MOF spherical nanoparticles in the composite material are NiFe MOFs nanoparticles.
[0054] For those not covered above, the prior art shall apply.
[0055] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the technical field to which the present invention pertains may make various modifications or supplements to the specific embodiments described, or use similar means for substitution, without departing from the direction of the present invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent substitution, improvement, etc. made to the above embodiments based on the technical essence of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for preparing in-situ grown graphene / MOF composite microrods, characterized in that: The following steps are involved: Step S1: injecting a mixed slurry consisting of graphene oxide and organic small molecule ligands into a rotating turntable containing a metal salt solution coagulation bath through a syringe to obtain a composite gel microrod suspension; Step S2: subjecting the composite gel microrod suspension to a hydrothermal reaction, followed by natural cooling to room temperature; Step S3: Filter the cooled microrod slurry obtained in step S2, wash it with a volatile organic solvent to obtain a graphene / MOF composite microrod mixed slurry, and then dry and grind it to obtain graphene / MOF composite microrods.
2. The preparation method according to claim 1, characterized in that: In step S1, the mixed slurry is obtained by liquid-liquid mixing of a graphene oxide solution and an organic small molecule ligand dispersion, and then dispersing the mixture by ultrasonic vibration; wherein the solvent in the graphene oxide solution is one of water, N,N-dimethylformamide, and N-methyl-2-pyrrolidone, and the concentration is 5-45 mg / ml.
3. The preparation method according to claim 2, characterized in that: The organic ligand in the organic small molecule ligand dispersion is one of 2-methylimidazole, 2,6-naphthalene dicarboxylic acid, terephthalic acid, and 2,5-dihydroxyterephthalic acid, and the solvent is one of water, ethanol, methanol, and N,N-dimethylformamide, and the concentration is 0.01-45 mol / L.
4. The preparation method according to claim 1, characterized in that: The molar ratio of graphene oxide to the organic small molecule ligand is 1:3-12.
5. The preparation method according to claim 1, characterized in that: In step S1, the metal salt in the metal salt solution coagulation bath is Zn 2+ 、Co 2+ 、Ni 2+ , Fe 3+ , Cu 2+ 、Zr 4+ The corresponding solvent is one of water, ethanol, methanol, N, N-dimethylformamide or a mixture of two of them.
6. The preparation method according to claim 1, characterized in that: In step S1, the needle tube is a screw-mouth needle tube with a volume of 5-100 ml, the matching needle is a 100-200 mm long needle, the inner diameter of the needle is between 50-550 μm, and the injection speed is controlled between 0.1-3.0 ml / min.
7. The preparation method according to claim 1, characterized in that: In step S2, a hydrothermal reaction is carried out at 60-150° C. for 3-24 hours, followed by natural cooling to room temperature.
8. The preparation method according to claim 1, characterized in that: The volatile organic solvent is acetone, which is filtered and washed with a 200-1000 mesh filter screen, and the filtering and washing are repeated 2-4 times.
9. The preparation method according to claim 1, characterized in that: In step S3, drying is performed by transferring the obtained graphene to a polytetrafluoroethylene container and drying the obtained graphene in an oven at 60-120° C.; grinding is performed by rapidly grinding the obtained graphene using a micro grinder for 5-120 seconds to obtain the corresponding graphene / MOF composite microrods; The graphene / MOF composite microrod mixed slurry is a suspension obtained after acetone filtering and washing and adding 10-150 ml of acetone.
10. An in-situ grown graphene / MOF composite microrod prepared by the preparation method according to any one of claims 1 to 9.