Porous carbon composite material

Abstract

According to the porous carbon composite material, MOF immobilization is achieved through the extremely high specific surface area and the high porosity of porous carbon, the conductive performance of the MOFs material is effectively improved through the porous carbon, and in addition, the porous carbon material with the millimeter-level thickness and the high specific surface area is obtained through multiple times of electro-deposition-roasting-chambering treatment.

Description

Technical Field

[0001] This invention belongs to the field of novel carbon composite material preparation, and particularly relates to a method for preparing a high specific surface area porous carbon material for water purification. Background Technology

[0002] Due to their high specific surface area, high porosity, high organic content, and controllable structure, MOFs can be used to construct nanoporous carbon materials with highly tunable structural properties. As a result, MOFs have become excellent precursors / templates for the preparation of NPCs, and the porous carbon materials prepared in this way almost perfectly inherit the framework structure of the precursors.

[0003] Generally, the preparation of porous carbon materials using MOFs mainly involves wet chemical methods and high-temperature calcination methods. The wet chemical method utilizes the instability of MOFs in solvents. Firstly, solvent molecules may replace organic ligands in the MOFs to coordinate with the central metal / metal cluster. Secondly, solvent molecules may attack the framework structure of the MOFs. Both results cause the original framework structure of the MOFs to collapse, forming a new framework structure, thus preparing MOF derivatives. The high-temperature calcination method involves preparing nanocomposites in a tubular furnace with a protective atmosphere by changing the protective atmosphere conditions and adjusting the heating rate. Generally, using nitrogen or argon as the protective atmosphere yields metallic or porous carbon nanomaterials, while using oxygen or air as the protective atmosphere yields metal oxides. Therefore, the chosen calcination temperature, calcination time, heating rate, and atmospheric conditions all affect the final product. Furthermore, multi-level nanostructured materials can be obtained by selecting different calcination temperatures and atmospheric conditions. For example, CN104229768A describes a method for preparing porous carbon with a three-dimensional structure, where zinc nitrate hexahydrate and terephthalic acid are mixed in a basic ratio of 3 mol:1 mol. The mixture is then shaken and heated at 120-150℃ for 4-6 hours. The resulting white powder (MOF-5) is filtered and dried in a desiccator for 12 hours. Finally, MOF-5 is placed in a tube furnace and calcined at 900-1000℃ under nitrogen for 1 hour. After natural cooling, the black three-dimensional porous carbon material is removed, exhibiting a specific surface area exceeding 1000 m²g⁻¹. This method for producing porous carbon requires no precursors and is simple and convenient. The synthesized porous carbon material possesses a perfect three-dimensional porous structure and good electrical conductivity and thermal stability.

[0004] Due to their high specific surface area, ability to provide unsaturated metal active sites, simple and easy synthesis methods, and diverse structures, MOFs can be directly used as electrocatalytic materials. However, researchers have discovered that by combining MOFs with materials exhibiting good conductivity, such as graphene and carbon nanotubes, and by converting the organic ligands and central metal ions in the MOFs into inorganic functionalized materials, the synergistic effect between the composite materials can preserve the original framework morphology of the MOFs while utilizing the excellent conductivity of the conductive materials, effectively compensating for the shortcomings of single-phase materials in practical applications. For example, CN105845458A discloses a graphene-activated metal-organic framework electrode material and its preparation and application. The preparation method includes: adding a soluble salt containing metal ions and an organic ligand to a solvent, maintaining the reaction temperature at 100℃-150℃ for 24-30 hours to obtain a MOF structured material; ultrasonically dispersing the MOF structured material in a solvent, then adding graphene, and reacting for 10-60 minutes to obtain a graphene-activated MOF electrode material. The metal-organic framework material described in this invention has advantages such as porosity, large specific surface area, tunable structure, and structural diversity, and the material preparation process is simple. When used as a supercapacitor electrode material, it exhibits excellent cycle stability and high discharge specific capacity, with a specific capacitance as high as 280 F / g, and good stability.

[0005] Based on the above understanding, in existing technologies for preparing porous carbon using MOFs as templates, the MOF is usually prepared first, followed by the porous carbon. Methods for preparing MOFs typically include diffusion, solvothermal (hydrothermal), and electrochemical methods. The electrochemical method utilizes electrolysis to induce electrode reactions in an electrolyte containing organic ligands, allowing crystals to grow continuously. Electrochemical technology can be used for large-scale industrial production of MOF powders. Compared to solvothermal synthesis, this method has the advantages of lower reaction temperature and faster synthesis rate. For example, CN114369854A discloses a universal and efficient method for preparing metal-organic framework (MOF) films. This method includes: electrodepositing a highly active metal layer as a substrate modification layer to provide active sites for MOF film nucleation and growth, enhancing the interaction between the MOF and the substrate; and using cathodic electrodeposition to prepare a uniform and continuous MOF film on the modified substrate surface. The preparation method described in this invention is not limited by conductive substrates. It not only effectively solves the problems of incompatibility between MOFs and substrate surfaces and the difficulty of heterogeneous nucleation, but also significantly improves the shortcomings of MOFs themselves, such as poor conductivity and structural instability. The preparation method of this invention is simple, efficient, and widely applicable, enabling industrial-scale promotion. The MOF films prepared by this method not only exhibit excellent rate discharge performance and cycle stability in supercapacitors, but also show promising application prospects in batteries, catalysis, and sensors.

[0006] However, as those skilled in the art know, the poor conductivity of MOFs limits their use in electrochemistry. For example, when MOFs are deposited on a conductive material substrate by electrochemical methods, the conductivity decreases linearly as the MOF grows and its thickness increases. This leads to a decrease in the MOF deposition rate, making it impossible to obtain a thick MOF layer, which is usually on the micrometer scale. This means that it is impossible to obtain a thick porous carbon layer by electrochemically preparing MOF-derived porous carbon, i.e., it is impossible to obtain millimeter-scale porous carbon on a conductive substrate.

[0007] Furthermore, water resources are the foundation of all human activities, and with the rapid progress of human civilization, water pollution has become increasingly severe globally. Currently, the main cause of water pollution is the large-scale discharge of industrial and agricultural wastewater, as well as domestic sewage, into water bodies without proper treatment. Industrial methods for treating phenolic wastewater mainly include physical, biochemical, and chemical methods. Chemical methods primarily rely on the reaction of coagulants or oxidants with phenolic pollutants to achieve purification. Commonly used methods include coagulation sedimentation and various advanced oxidation processes (AOPs). AOPs have received increasing research and attention in the field of industrial water treatment. Through various activation methods and the synergistic effect of oxidants to generate free radicals, most organic pollutants can be completely degraded into CO2 and H2O. This method has a fast reaction rate and is effective against many pollutants. Phenolic pollutants are broadly applicable and can be completely mineralized, thus requiring no further treatment. Furthermore, the process is simple and is gradually becoming a research hotspot in the industry. Depending on the catalytic conditions, advanced oxidation methods can be categorized into Fenton oxidation, ozone oxidation, electrochemical oxidation, photocatalytic oxidation, and the recently emerging persulfate-based advanced oxidation technology. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a porous carbon composite material and its preparation method. The composite material is used as a base component for porous carbon-bimetallic materials in water purification. The bimetallic and MOF-derived porous carbon possesses fundamental characteristics such as unsaturated metal active sites, diverse and controllable structures that are easily modified, high specific surface area, and simple synthesis methods. In the water purification process, the extremely high specific surface area and porosity of the porous carbon are used to immobilize MOFs, and the porous carbon effectively improves the electrical conductivity of MOF materials. Furthermore, multiple electrodeposition-calcination-pore expansion treatments yield millimeter-thick porous carbon materials with high specific surface area, providing an application basis for electrode catalytic oxidation and degradation of wastewater. Specifically…

[0009] A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole expansion treatment to obtain substrate GR-1PC Graphite Rod-1 Porous Carbon; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-xPC, x=3~4; The process parameters for the first and second Ni-MOF layers deposited on the surface are consistent. Conductive graphite rods and GR-1PC are used as cathodes, and inert conductive metal materials are used as anodes. The electrodes are immersed in an electrolyte and constant voltage electrodeposition is performed at a voltage of -7V to -3V for 15-20 minutes at room temperature. The electrolyte consists of 0.3-0.5mM nickel chloride, 0.1-0.2M potassium nitrate, 0.5-1mM trimesic acid, 2-5ml ethanol, 0.3-0.5mM triethylmethylammonium chloride, 0.5-1g P123 surfactant, and deionized water. The electrolyte is prepared by stirring thoroughly for 5-10 minutes. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: Increase the temperature to 600-650℃ at 5-7℃ / min, hold for 1-2 hours, then increase the temperature to 900-920℃ at 10-12℃ / min, hold for 4-5 hours, and allow to cool naturally. The process parameters for the first and second pore-expanding treatments are the same. The pore-expanding step involves using a deionized aqueous solution of 0.3-0.5M HCl and 0.1-0.2g sodium dodecylbenzenesulfonate as the pore-expanding solution, and the pore-expanding method is ultrasonic immersion. The immersion time is 5-7 minutes, the ultrasonic frequency is 10-20KHZ, and the temperature is 25-30℃.

[0010] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0011] Degreasing solution: Na3PO4 6-10g / L, sodium carbonate 10-12g / L, temperature 70-75℃, time 10-12min, hydrochloric acid concentration 15-20wt.%, time 3-5min, temperature room temperature.

[0012] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is blower drying at 100-120°C.

[0013] The roasting atmosphere is an inert gas, such as nitrogen or argon.

[0014] The final obtained porous carbon composite material uses a conductive material as a substrate, on which high-surface-area porous carbon is deposited. The specific surface area of ​​the porous carbon is 1700-1900 m². 2 / g, total pore volume is 1.3-2.7cm³ 3 / g, micropore volume 0.65-0.93 cm³ 3 / g, wherein the thickness of the porous carbon material is 1-5mm; Furthermore, the conductive materials of the present invention include, but are not limited to, one of graphite carbon rods, carbon nanotube rods, graphene rods, carbon cloth, carbon fiber, nickel foam, and titanium foam, as long as they have feasible conductivity.

[0015] The preparation process of this invention can be briefly described as follows: pretreatment of the conductive substrate, electrochemical deposition of MOF on the surface of the conductive substrate, raising the pH value of the cathode surface by applying current, deprotonating the neutral organic ligand in the alkaline environment and combining with metal ions to form MOF crystals, and increasing the local pH value near the cathode surface by triethylmethylammonium chloride, thereby causing the deprotonation of trimesic acid, which then combines with metal salts such as nickel or cobalt to form crystal nuclei, thereby forming a Ni-MOF layer on the surface of the conductive substrate. This method is simple to prepare, with low voltage, low temperature and short time. In addition, during the electrodeposition process, an appropriate surfactant should be added to improve the wetting effect (contact surface) between the conductive metal or the subsequent porous carbon (GR-1PC, GR-2PC, GR-3PC, GraphiteRod-X Porous Carbon) and the electrolyte.

[0016] Then, using Ni-MOFs as templates, high-temperature calcination under nitrogen or argon atmospheres is performed. The resulting Ni-porous material inherits the high specific surface area and uniform pore structure of MOFs. Compared to the original MOF, the specific surface area is significantly increased after calcination in an inert atmosphere. The calcination temperature program is as follows: heating at 5-7℃ / min to 600-650℃, holding for 1-2 hours, then heating at 10-12℃ / min to 900-920℃, holding for 4-5 hours, and then naturally cooling. Nitrogen calcination is preferred here, as it can modify the carbon material; nitrogen doping can improve the electrical conductivity and wettability of porous carbon. When preparing porous carbon-bimetallic MOF water purification materials, the hybridization of the p orbitals of the doped nitrogen atoms with the d orbitals of the metal catalyst atoms increases the binding energy, improves the stability of the water purification material, and the increased conductivity enhances the electron transport rate, thereby improving the catalytic activity.

[0017] The porous carbon bottom layer obtained by nitrogen calcination contains a large number of metal ions, or metal oxides, such as nickel oxide. This can lead to the blockage of the pores by the metal oxides. The metal oxides are removed by pore expansion, thereby further increasing the specific surface area of ​​the porous carbon material. The pore expansion method is to use a deionized aqueous solution of 0.3-0.5M HCl and 0.1-0.2g sodium dodecylbenzenesulfonate as the pore expansion solution. The pore expansion method is ultrasonic immersion for 5-7 minutes, with an ultrasonic frequency of 10-20KHZ and a temperature of 25-30℃. The oxides remaining after calcination are removed by corrosion. Then, the expanded material is washed and dried.

[0018] A porous carbon material, GR-1PC, with a nitrogen-doped porous carbon surface exhibiting extremely high conductivity, was obtained through an electrodeposition-calcination-pore-expansion process. This process involved depositing MOF on the substrate and repeating the deposition, calcination, and pore-expansion steps to obtain GR-xPC, a porous carbon material with x=3~4. This effectively avoids the technical problem of MOF conductivity decreasing with thickness, which prevents the achievement of millisecond-level porous carbon. The final porous carbon material obtained has a specific surface area of ​​1700-1900 m². 2 / g, total pore volume is 1.3-2.7cm³ 3 / g, micropore volume 0.65-0.93 cm³ 3 / g, wherein the thickness of the porous carbon material is 1-5mm.

[0019] Based on the preparation of the porous carbon described above, bimetallic MOF materials are deposited on its surface for water purification.

[0020] A method for preparing a carbon-based water purification material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole expansion treatment to obtain substrate GR-1PC Graphite Rod-1 Porous Carbon; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) The third deposition, third calcination and third pore expansion steps are used to obtain porous carbon material GR-3PC; (8) Using GR-3PC as the working electrode, a bimetallic MOF layer is electrodeposited on its surface, and then a fourth calcination treatment is performed to obtain the water purification material; The process parameters for the first, second, and third Ni-MOF layers deposited on the surface are consistent. The substrate to be treated is used as the cathode, and the inert conductive metal material is used as the anode. The substrate is immersed in an electrolyte and constant voltage electrodeposition is used. The voltage is -7V to -3V, the time is 15-20min, and the temperature is at room temperature. The electrolyte is composed of 0.3-0.5mM nickel chloride, 0.1-0.2M potassium nitrate, 0.5-1mM trimesic acid, 2-5ml ethanol, 0.3-0.5mM triethylmethylammonium chloride, 0.5-1g P123 surfactant, and deionized water. The electrolyte is prepared by stirring thoroughly for 5-10min. The first, second, third, and fourth temperature-controlled roasting processes were identical, and the temperature-controlled steps were as follows: Increase the temperature to 600-650℃ at 5-7℃ / min, hold for 1-2 hours, then increase the temperature to 900-920℃ at 10-12℃ / min, hold for 4-5 hours, and allow to cool naturally. The process parameters for the first, second, and third pore-expanding treatments are the same as those for the second pore-expanding treatment. The pore-expanding step involves using a deionized aqueous solution of 0.3-0.5M HCl and 0.1-0.2g sodium dodecylbenzenesulfonate as the pore-expanding solution, and the pore-expanding method is ultrasonic immersion. The immersion time is 5-7 minutes, the ultrasonic frequency is 10-20KHZ, and the temperature is 25-30℃. The electrodeposited bimetallic MOF layer: using GR-3PC as the cathode and an inert conductive metal material as the anode, immersed in an electrolyte, constant voltage electrodeposition is performed at a voltage of -7V to -3V for 15-20 minutes at room temperature. The electrolyte consists of 0.2-0.4mM ferric chloride, 0.1-0.2mM manganese chloride, 0.1-0.2M potassium nitrate, 0.5-1mM trimesic acid, 2-5ml ethanol, 0.3-0.5mM triethylmethylammonium chloride, 0.5-1g P123 surfactant, and deionized water. After stirring thoroughly for 5-10 minutes, the electrolyte is used. After electrodeposition, the material is washed with deionized water and dried under programmed temperature rise to obtain the Fe-Mn bimetallic porous carbon catalyst.

[0021] The Fe-Mn bimetallic porous carbon material was subjected to adsorption and catalytic oxidation tests using the advanced oxidation method. In short, this invention generates SO4 by activating persulfate PMS with the composite material. •− To oxidize and degrade organic pollutants, relative to •OH, SO4 •− It has a higher redox potential and is applicable to a wider pH range, exhibiting strong oxidizing ability in both acidic and alkaline environments.

[0022] Activity testing process: The catalytic oxidation of phenol was carried out in a 100 mL screw-top flask. Phenol solution and Fe-Mn bimetallic porous carbon (excluding conductive substrates such as carbon rods) were added to the screw-top flask and ultrasonically dispersed for 0.5 h. The mixture was stirred at 800 rpm. Timing was started after the addition of potassium peroxymonosulfonate (PMS), and 0.5 mL samples were taken at intervals. Each sample was filtered through a 0.22 μm filter membrane and mixed with 0.5 mL of methanol to quench free radicals and terminate the reaction. The mixture was then transferred to a liquid chromatography vial and analyzed by Ultimate 3000 high-performance liquid chromatography (HPLC). The chromatographic column was C18, the UV lamp wavelength was set to 270 nm, and the mobile phase consisted of 40% acetonitrile and 60% deionized water at a flow rate of 1 mL / min.

[0023] Adsorption test: The adsorption test was carried out in a 250 mL screw-top bottle. 0.005 g of catalyst was dispersed in a 0.02 g / L phenol solution and placed on a magnetic stirrer at a speed of 500 rpm. Samples were taken at intervals, each time 0.5 mL. The sample was filtered through a 0.22 μm filter membrane and mixed with 0.5 mL of methanol. The mixture was then transferred to a liquid chromatography vial for liquid chromatography analysis.

[0024] Beneficial technical effects: (1) This invention fully utilizes the advantages of electrochemical deposition in preparing MOFs, preparing MOF layers under low temperature, low pressure, and low time consumption conditions, and using these layers as porous carbon templates. Through calcination and pore expansion, porous carbon with high specific surface area is obtained. The porous carbon has high conductivity. This is then used as a substrate in a cyclic electrodeposition-calcination-pore expansion process, ultimately yielding millimeter-scale porous carbon materials. The obtained porous material is a three-dimensional framework porous carbon with a specific surface area of ​​1700-1900 m². 2 / g, total pore volume is 1.3-2.7cm³ 3 / g, micropore volume 0.65-0.93 cm³ 3 / g, the thickness of the porous carbon material is 1-5mm, and its high specific surface area gives it a high adsorption and water purification capacity.

[0025] (2) Using the above porous material as the substrate, a bimetallic water purification material is prepared. The manganese-iron bimetals work together to activate PMS, promote the generation of more free radicals, and thus improve the water purification effect. Attached Figure Description

[0026] Appendix Figure 1 SEM image of porous carbon material prepared in Example 2 of this invention.

[0027] Appendix Figure 2 Figure 5 shows the bimetallic water purification material prepared in Example 5 of this invention (before calcination). Detailed Implementation Example 1

[0028] A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole enlargement treatment to obtain substrate GR-1PC; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; The process parameters for the first and second Ni-MOF layers deposited on the surface are consistent. Conductive graphite rods and GR-1PC are used as cathodes, and inert conductive metal materials are used as anodes. The materials are immersed in an electrolyte and constant voltage electrodeposition is performed at -7V for 15 minutes at room temperature. The electrolyte consists of 0.3mM nickel chloride, 0.1M potassium nitrate, 0.5mM trimesic acid, 2ml ethanol, 0.3mM triethylmethylammonium chloride, 0.5g P123 surfactant, and deionized water. The solution is stirred thoroughly for 5 minutes before being used as the electrolyte. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: The temperature was increased to 600℃ at 5℃ / min and held for 1 hour. Then the temperature was increased to 900℃ at 10℃ / min and held for 4 hours. The temperature was then allowed to cool naturally. The calcination atmosphere was nitrogen. The process parameters for the first and second pore-expanding treatments are the same. The pore-expanding step uses a deionized aqueous solution of 0.3M HCl and 0.1g sodium dodecylbenzenesulfonate as the pore-expanding solution. The pore-expanding method is ultrasonic immersion, with an immersion time of 5 minutes, an ultrasonic frequency of 10KHZ, and a temperature of 25℃.

[0029] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0030] Degreasing solution: Na3PO4 6g / L, sodium carbonate 10g / L, temperature 70℃, time 10min, hydrochloric acid concentration 15wt.%, time 3min, temperature room temperature.

[0031] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 100°C forced air drying.

[0032] Example 2 A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole enlargement treatment to obtain substrate GR-1PC; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-3PC; The process parameters for the first and second Ni-MOF layers deposited on the surface are consistent. Conductive graphite rods and GR-1PC are used as cathodes, and inert conductive metal materials are used as anodes. The electrodes are immersed in an electrolyte and constant voltage electrodeposition is performed at -5V for 17.5 min at room temperature. The electrolyte consists of 0.4 mM nickel chloride, 0.15 M potassium nitrate, 0.75 mM trimesic acid, 3.5 ml ethanol, 0.4 mM triethylmethylammonium chloride, 0.75 g P123 surfactant, and deionized water. The electrolyte is prepared by stirring for 7.5 min. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: The temperature was increased to 625℃ at 6℃ / min and held for 1.5h, then increased to 910℃ at 11℃ / min and held for 4.5h, and then cooled naturally. The calcination atmosphere was nitrogen. The process parameters for the first and second pore-expanding treatments are the same. The pore-expanding step uses a deionized aqueous solution of 0.4MHCl and 0.15g sodium dodecylbenzenesulfonate as the pore-expanding solution. The pore-expanding method is ultrasonic immersion, with an immersion time of 6 minutes, an ultrasonic frequency of 15KHZ, and a temperature of 27.5℃.

[0033] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0034] Degreasing solution: Na3PO4 8g / L, sodium carbonate 11g / L, temperature 72.5℃, time 11min, hydrochloric acid concentration 17.5wt.%, time 4min, temperature room temperature.

[0035] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 110°C forced air drying.

[0036] Example 3 A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole expansion treatment to obtain substrate GR-1PC Graphite Rod-1 Porous Carbon; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-4PC; The process parameters for the first and second Ni-MOF layers deposited on the surface are consistent. Conductive graphite rods and GR-1PC are used as cathodes, and inert conductive metal materials are used as anodes. The electrodes are immersed in an electrolyte and constant voltage electrodeposition is performed at -3V for 20 minutes at room temperature. The electrolyte consists of 0.5mM nickel chloride, 0.2M potassium nitrate, 1mM trimesic acid, 5ml ethanol, 0.5mM triethylmethylammonium chloride, 1g P123 surfactant, and deionized water. The electrolyte is stirred thoroughly for 10 minutes. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: The temperature was increased to 650℃ at 7℃ / min and held for 2 hours. Then the temperature was increased to 920℃ at 12℃ / min and held for 5 hours. The temperature was then allowed to cool naturally. The calcination atmosphere was nitrogen. The process parameters for the first and second pore-expanding treatments are the same. The pore-expanding step uses a deionized aqueous solution of 0.5MHCl and 0.2g sodium dodecylbenzenesulfonate as the pore-expanding solution. The pore-expanding method is ultrasonic immersion, with an immersion time of 7 minutes, an ultrasonic frequency of 20KHZ, and a temperature of 30℃.

[0037] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0038] Degreasing solution: Na3PO4 10g / L, sodium carbonate 12g / L, temperature 75℃, time 12min, hydrochloric acid concentration 20wt.%, time 5min, temperature room temperature.

[0039] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 120°C forced air drying.

[0040] Example 4 A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole enlargement treatment to obtain substrate GR-1PC; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-3PC; (8) Using GR-3PC as the working electrode, a bimetallic MOF layer is electrodeposited on its surface, and then a fourth calcination treatment is performed to obtain the water purification material.

[0041] The surface deposition of the Ni-MOF layer uses the same process parameters, with conductive graphite rods and GR-1PC as cathodes and inert conductive metal materials as anodes, immersed in an electrolyte. Constant voltage electrodeposition is used, with a voltage of -5V and a time of 17.5min at room temperature. The electrolyte consists of 0.4mM nickel chloride, 0.15M potassium nitrate, 0.75mM trimesic acid, 3.5ml ethanol, 0.4mM triethylmethylammonium chloride, 0.75g P123 surfactant, and deionized water. The electrolyte is prepared by stirring thoroughly for 7.5min. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: The temperature was increased to 625℃ at 6℃ / min and held for 1.5h, then increased to 910℃ at 11℃ / min and held for 4.5h, and then cooled naturally. The calcination atmosphere was nitrogen. The pore-expansion process parameters are consistent. The pore-expansion step is to use a deionized aqueous solution of 0.4M HCl and 0.15g sodium dodecylbenzenesulfonate as the pore-expansion solution. The pore-expansion method is ultrasonic immersion, the immersion time is 6min, the ultrasonic frequency is 15KHZ, and the temperature is 27.5℃.

[0042] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0043] Degreasing solution: Na3PO4 8g / L, sodium carbonate 11g / L, temperature 72.5℃, time 11min, hydrochloric acid concentration 17.5wt.%, time 4min, temperature room temperature.

[0044] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 110°C forced air drying.

[0045] The electrodeposited bimetallic MOF layer was prepared by using GR-3PC as the cathode and an inert conductive metal material as the anode, immersed in an electrolyte, and electrodeposited at a constant voltage of -7V for 15 minutes at room temperature. The electrolyte consisted of 0.2mM ferric chloride, 0.1mM manganese chloride, 0.1M potassium nitrate, 0.5mM trimesic acid, 2ml ethanol, 0.3mM triethylmethylammonium chloride, 0.5g P123 surfactant, and deionized water. The solution was stirred thoroughly for 5 minutes before being used as the electrolyte. After electrodeposition, the material was washed with deionized water and dried under programmed temperature rise to obtain the Fe-Mn bimetallic porous carbon catalyst.

[0046] Example 5 A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole enlargement treatment to obtain substrate GR-1PC; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-3PC; (8) Using GR-3PC as the working electrode, a bimetallic MOF layer is electrodeposited on its surface, and then a fourth calcination treatment is performed to obtain the water purification material.

[0047] The surface deposition of the Ni-MOF layer uses the same process parameters, with conductive graphite rods and GR-1PC as cathodes and inert conductive metal materials as anodes, immersed in an electrolyte. Constant voltage electrodeposition is used, with a voltage of -5V and a time of 17.5min at room temperature. The electrolyte consists of 0.4mM nickel chloride, 0.15M potassium nitrate, 0.75mM trimesic acid, 3.5ml ethanol, 0.4mM triethylmethylammonium chloride, 0.75g P123 surfactant, and deionized water. The electrolyte is prepared by stirring thoroughly for 7.5min. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: The temperature was increased to 625℃ at 6℃ / min and held for 1.5h, then increased to 910℃ at 11℃ / min and held for 4.5h, and then cooled naturally. The calcination atmosphere was nitrogen. The pore-expansion process parameters are consistent. The pore-expansion step is to use a deionized aqueous solution of 0.4M HCl and 0.15g sodium dodecylbenzenesulfonate as the pore-expansion solution. The pore-expansion method is ultrasonic immersion, the immersion time is 6min, the ultrasonic frequency is 15KHZ, and the temperature is 27.5℃.

[0048] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0049] Degreasing solution: Na3PO4 8g / L, sodium carbonate 11g / L, temperature 72.5℃, time 11min, hydrochloric acid concentration 17.5wt.%, time 4min, temperature room temperature.

[0050] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 110°C forced air drying.

[0051] The electrodeposited bimetallic MOF layer was prepared by using GR-3PC as the cathode and an inert conductive metal material as the anode, immersed in an electrolyte, and electrodeposited at a constant voltage of -5V for 17.5 min at room temperature. The electrolyte consisted of 0.3 mM ferric chloride, 0.15 mM manganese chloride, 0.15 M potassium nitrate, 0.75 mM trimesic acid, 3.5 ml ethanol, 0.4 mM triethylmethylammonium chloride, 0.75 g P123 surfactant, and deionized water. After stirring thoroughly for 7.5 min, the electrolyte was used as the electrodeposit. After electrodeposition, the material was washed with deionized water and dried under programmed temperature rise to obtain the Fe-Mn bimetallic porous carbon catalyst.

[0052] Example 6 A method for preparing a porous carbon material includes the following steps: (1) A first Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) First programmed temperature rise roasting treatment; (3) First hole enlargement treatment to obtain substrate GR-1PC; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-3PC; (8) Using GR-3PC as the working electrode, a bimetallic MOF layer is electrodeposited on its surface, and then a fourth calcination treatment is performed to obtain the water purification material.

[0053] The surface deposition of the Ni-MOF layer uses the same process parameters, with conductive graphite rods and GR-1PC as cathodes and inert conductive metal materials as anodes, immersed in an electrolyte. Constant voltage electrodeposition is used, with a voltage of -5V and a time of 17.5min at room temperature. The electrolyte consists of 0.4mM nickel chloride, 0.15M potassium nitrate, 0.75mM trimesic acid, 3.5ml ethanol, 0.4mM triethylmethylammonium chloride, 0.75g P123 surfactant, and deionized water. The electrolyte is prepared by stirring thoroughly for 7.5min. The first and second programmed temperature-increasing roasting processes are identical, and the programmed temperature-increasing steps are as follows: The temperature was increased to 625℃ at 6℃ / min and held for 1.5h, then increased to 910℃ at 11℃ / min and held for 4.5h, and then cooled naturally. The calcination atmosphere was nitrogen. The pore-expansion process parameters are consistent. The pore-expansion step is to use a deionized aqueous solution of 0.4M HCl and 0.15g sodium dodecylbenzenesulfonate as the pore-expansion solution. The pore-expansion method is ultrasonic immersion, the immersion time is 6min, the ultrasonic frequency is 15KHZ, and the temperature is 27.5℃.

[0054] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0055] Degreasing solution: Na3PO4 8g / L, sodium carbonate 11g / L, temperature 72.5℃, time 11min, hydrochloric acid concentration 17.5wt.%, time 4min, temperature room temperature.

[0056] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 110°C forced air drying.

[0057] The electrodeposited bimetallic MOF layer was prepared by using GR-3PC as the cathode and an inert conductive metal material as the anode, immersed in an electrolyte, and electrodeposited at a constant voltage of -3V for 20 minutes at room temperature. The electrolyte consisted of 0.4mM ferric chloride, 0.1-0.2mM manganese chloride, 0.2M potassium nitrate, 1mM trimesic acid, 5ml ethanol, 0.5mM triethylmethylammonium chloride, 1g P123 surfactant, and deionized water. The solution was stirred thoroughly for 10 minutes and then used as the electrolyte. After electrodeposition, the material was washed with deionized water and dried under programmed temperature rise to obtain the Fe-Mn bimetallic porous carbon catalyst.

[0058] The specific surface area of ​​Examples 2 and 5 was characterized. Example 2: The specific surface area of ​​porous carbon is 1803 m². 2 / g, total pore volume is 2.70cm³ 3 / g, micropore volume 0.92 cm³ 3 / g, as attached Figure 1 As shown; the specific surface area of ​​the bimetallic porous carbon in Example 5 is 1675 m². 2 / g, total pore volume is 1.33cm³ 3 / g, micropore volume 0.68 cm³ 3 / g; It can be seen that in Example 5, without pore-expansion treatment, the specific surface area and pore volume are significantly reduced, but this also indirectly shows that the bimetallic component can be uniformly dispersed in porous carbon; In addition, as shown in the appendix Figure 2 As shown, electrochemical MOF deposition on porous carbon results in a significant coating on the porous layer surface.

[0059] Comparative Example 1 A method for preparing a porous carbon material includes the following steps: (1) A Ni-MOF layer is deposited on the surface of a conductive graphite rod as a substrate; (2) Programmed heating and roasting treatment; (3) Hole enlargement treatment, drying and washing to obtain substrate GR-1PC; The Ni-MOF layer process uses conductive graphite rods and GR-1PC as cathodes and inert conductive metal materials as anodes, respectively, immersed in an electrolyte. Constant voltage electrodeposition is employed at a voltage of -5V for 120 minutes at room temperature. The electrolyte consists of 0.4mM nickel chloride, 0.15M potassium nitrate, 0.75mM trimesic acid, 3.5ml ethanol, 0.4mM triethylmethylammonium chloride, 0.75g P123 surfactant, and deionized water. The mixture is stirred thoroughly for 7.5 minutes to obtain the electrolyte. The roasting process, including the programmed temperature rise steps, is as follows: The temperature was increased to 625℃ at 6℃ / min and held for 1.5h, then increased to 910℃ at 11℃ / min and held for 4.5h, and then cooled naturally. The calcination atmosphere was nitrogen. The pore-expanding process involves using a deionized aqueous solution of 0.4M HCl and 0.15g sodium dodecylbenzenesulfonate as the pore-expanding solution, and ultrasonic immersion for 6 minutes at a frequency of 15kHz and a temperature of 27.5℃.

[0060] The graphite rod is subjected to degreasing, washing, and activation treatments in sequence. The degreasing solution used is a mixture of sodium phosphate and sodium carbonate. The washing is done with deionized water. The activation is done with hydrochloric acid aqueous solution.

[0061] Degreasing solution: Na3PO4 8g / L, sodium carbonate 11g / L, temperature 72.5℃, time 11min, hydrochloric acid concentration 17.5wt.%, time 4min, temperature room temperature.

[0062] After pore enlargement, the process includes washing and drying. The washing is deionized washing, and the drying is 110°C forced air drying.

[0063] The thickness of the carbon rod to the outermost porous carbon material obtained in Example 2 was 2.37 mm. In Comparative Example 1, the electrodeposition time was extended to 120 min, but the thickness of the porous carbon obtained was only about 600-700 micrometers. Obviously, simply extending the time cannot obtain a thick layer of porous carbon material.

[0064] Adsorption experiments were conducted on the materials of Examples 2 and 4. The porous carbon material of Example 2 showed an adsorption capacity of more than 72.1% for phenol, while the adsorption capacity of Example 5 decreased to 59.3% due to the reduction in surface area and pore volume. The catalytic performance was tested under the following conditions: phenol concentration of 0.03 g / L, PMS concentration of 2.1 g / L, and composite material dosage of 0.1 g / L (the weight of the conductive carbon rod substrate is not included in the composite material, only the weight of the porous carbon or bimetallic porous carbon). The carbon material obtained in Example 2 achieved a phenol removal rate of 78.3% after 10 minutes. In comparison, the bimetallic material obtained in Example 5 achieved a phenol removal rate of 99.9% within 3 minutes.

[0065] Then, using the material obtained in Example 5 as the substrate, the phenol removal rates at pH=2, pH=7, and pH=11 for 2.5 min were tested and found to be 95.3%, 94.1%, and 94.8%, respectively. It can be seen that the composite material of the present invention has extremely high catalytic effect across the entire pH range.

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A porous carbon composite material, wherein a conductive material is used as a substrate, and high-surface-area porous carbon is deposited on its surface, wherein the specific surface area of ​​the porous carbon is 1700-1900 m². 2 / g, total pore volume is 1.3-2.7cm³ 3 / g, micropore volume 0.65-0.93 cm³ 3 / g, wherein the thickness of the porous carbon material is 1-5mm; The porous carbon composite material was prepared by the following method: (1) A first Ni-MOF layer is deposited on the surface of a conductive material as a substrate; (2) First programmed heating and roasting treatment; (3) First hole expansion treatment to obtain substrate GR-1PC Graphite Rod-1 Porous Carbon; (4) Deposit a second Ni-MOF layer on the GR-1PC surface; (5) Second-stage temperature-increasing roasting treatment; (6) Second hole enlargement treatment to obtain substrate GR-2PC; (7) Repeat the above deposition, calcination and pore expansion steps to obtain porous carbon material GR-xPC, x=3~4; The process parameters for the first and second Ni-MOF layer depositions are consistent. Conductive graphite rods and GR-1PC are used as cathodes, and inert conductive metal materials are used as anodes. The layers are immersed in an electrolyte and constant voltage electrodeposition is employed at -7V to -3V for 15-20 minutes at room temperature. The electrolyte consists of 0.3-0.5mM nickel chloride, 0.1-0.2M potassium nitrate, 0.5-1mM trimesic acid, 2-5ml ethanol, 0.3-0.5mM triethylmethylammonium chloride, 0.5-1g P123 surfactant, and deionized water. The solution is stirred thoroughly for 5-10 minutes before use. The process for the first and second programmed temperature-increase roasting treatments is the same, and the programmed temperature-increase steps are as follows: Increase the temperature to 600-650℃ at 5-7℃ / min, hold for 1-2 hours, then increase the temperature to 900-920℃ at 10-12℃ / min, hold for 4-5 hours, and allow to cool naturally. The process parameters for the first and second pore enlargement treatments are the same. The pore enlargement step involves using a deionized aqueous solution of 0.3-0.5MHCl and 0.1-0.2g sodium dodecylbenzenesulfonate as the pore enlargement solution. The pore enlargement method is ultrasonic immersion, with an immersion time of 5-7 minutes, an ultrasonic frequency of 10-20KHZ, and a temperature of 25-30℃. The process after pore enlargement includes washing and drying. The washing is deionized washing, and the drying is forced air drying at 100-120°C.

2. The porous carbon composite material as described in claim 1, characterized in that... The conductive material is one of the following: graphite carbon rod, carbon nanotube rod, graphene rod, carbon cloth, carbon fiber, nickel foam, and titanium foam.

3. The porous carbon composite material as described in claim 1, characterized in that... The roasting atmosphere is an inert gas, such as nitrogen or argon.

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