A method for preparing porous carbon based on physical activation, porous carbon and its applications

Abstract

This invention relates to the field of carbon material preparation technology, and discloses a method for preparing porous carbon based on physical activation, porous carbon, and its applications. The method includes: heat-treating a carbonaceous precursor to obtain a carbonized material; heating to an activation temperature under an inert atmosphere, and conducting an activation reaction between a main activator and the carbonized material in a reactor to obtain the porous carbon; and removing impurities and drying the reaction tail gas obtained after the activation reaction to obtain gas I that can be recycled back to the reactor to participate in the activation reaction. This invention provides a method for preparing atmosphere-suppressed physically activated porous carbon based on tail gas recirculation, which can solve the problems of high cost and low safety of exogenous suppressing gases.

Description

Technical Field

[0001] This invention relates to the field of carbon material preparation technology, specifically to a method for preparing porous carbon based on physical activation, porous carbon, and its applications. Background Technology

[0002] Existing physical activation methods (such as steam or CO2 activation) are clean and low-cost, but they suffer from the drawback of difficulty in controlling the reaction rate. As the activation level increases, micropores tend to expand and collapse, forming medium- to large pores, making it difficult to obtain high-density ultramicropores (<1 nm). In addition, physical activation usually introduces a large number of oxygen-containing functional groups into the carbon surface, reducing the conductivity of the material and its cycling stability in organic electrolytes.

[0003] Existing improvement methods typically involve adjusting activation temperature or time, regulating the flow rate of physical activators, and pre-treatment of raw materials. This not only increases production costs or time, but some of these methods may also pose safety hazards.

[0004] Existing processes typically introduce external inert gases to regulate the concentration of physical activators within the furnace, thereby controlling the gasification reaction rate of the carbide. However, the consumption of external high-purity inert gases significantly increases production costs, and the inert gases only serve a physical dilution function, failing to effectively suppress the etching reaction from a chemical equilibrium perspective. Their effect in preventing micropore expansion and collapse is limited, making it difficult to obtain ultra-microporous structures with extremely narrow distributions.

[0005] In addition, some studies have attempted to suppress the activation reaction by introducing high-purity hydrogen to achieve precise pore formation. However, this approach has many problems in practical applications. For example, the preparation and storage costs of high-purity hydrogen are extremely high, and there are significant safety hazards under high-temperature activation conditions, with the risk of explosion. Furthermore, relying solely on external gas regulation does not achieve energy and component recycling, resulting in high overall energy consumption and failing to meet the requirements of green production. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of existing technologies, such as the difficulty in accurately controlling the micropore size distribution of porous carbon materials, high surface oxygen content, poor conductivity, and the cumbersome and energy-intensive physical activation method.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for preparing porous carbon based on physical activation, the method comprising: (1) Heat-treat the carbonaceous precursor to obtain carbonized material; (2) Under an inert atmosphere, the temperature is raised to the activation temperature, and the main activator and the carbonized material are activated in a reactor to obtain the porous carbon. The conditions of the activation reaction are controlled such that the volume concentration of the reducing gas in the reactor is 15-75 wt%; and the gasification and ablation rate of the carbide is 0.3 wt% / min-1.0 wt% / min. The reaction tail gas obtained after the activation reaction is subjected to impurity removal and drying treatment to obtain gas I that can be recycled back to the reactor to participate in the activation reaction; the volumetric flow rate of gas I accounts for 10-60% of the total gas volumetric flow rate entering the reactor. The conditions for the impurity removal and drying process are controlled such that the content of reducing gas in gas I is not less than 50 wt% and the water content in gas I is not more than 5 wt%. The main activator is selected from at least one of water vapor, carbon dioxide, and oxygen.

[0008] A second aspect of the invention provides porous carbon prepared by the method described in the first aspect.

[0009] A third aspect of the present invention provides the application of the porous carbon described in the second aspect in the field of electrochemical energy storage devices or the environmental field.

[0010] This invention addresses the technical problems of existing physical activation technologies, such as difficulty in precisely controlling reaction rates, easy expansion and collapse of micropores, and cumbersome and energy-intensive related improvement processes. It provides a method for preparing atmosphere-suppressed physically activated porous carbon based on tail gas recirculation and reinjection.

[0011] The present invention has at least the following beneficial effects: 1) The method for preparing porous carbon based on physical activation provided by this invention can solve the problem of the difficulty in accurately controlling the micropore size distribution.

[0012] 2) The method for preparing porous carbon based on physical activation provided by this invention can solve the problems of high oxygen content and poor conductivity on the surface of carbon materials.

[0013] 3) The method for preparing porous carbon based on physical activation provided by this invention can solve the problems of high cost and low safety of exogenous suppressant gas.

[0014] 4) The method for preparing porous carbon based on physical activation provided by this invention is low in cost, simple in process, and easy to scale up. Attached Figure Description

[0015] Figure 1 These are Raman images of the porous carbon prepared in Examples 1-4 and Comparative Examples 1-3 of the present invention; Figure 2 These are X-ray diffraction analysis patterns of porous carbon prepared in Examples 1-4 and Comparative Examples 1-3 of the present invention; Figure 3This is a flowchart of the preparation of porous carbon based on physical activation according to the present invention.

[0016] Explanation of reference numerals in the attached figures 1. Carbonaceous precursor raw materials; 2. Main activator source; 3. High-temperature activation reactor; 4. Porous carbon products; 5. Exhaust gas; 6. Exhaust gas purification and drying system; 7. Control valve; Detailed Implementation The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] As previously stated, a first aspect of the present invention provides a method for preparing porous carbon based on physical activation, the method comprising: (1) Heat-treat the carbonaceous precursor to obtain carbonized material; (2) Under an inert atmosphere, the temperature is raised to the activation temperature, and the main activator and the carbonized material are activated in a reactor to obtain the porous carbon. The conditions of the activation reaction are controlled such that the volume concentration of the reducing gas in the reactor is 15-75 wt%; and the gasification and ablation rate of the carbide is 0.3 wt% / min-1.0 wt% / min. The reaction tail gas obtained after the activation reaction is subjected to impurity removal and drying treatment to obtain gas I that can be recycled back to the reactor to participate in the activation reaction; the volumetric flow rate of gas I accounts for 10-60% of the total gas volumetric flow rate entering the reactor. The conditions for the impurity removal and drying process are controlled such that the content of reducing gas in gas I is not less than 50 wt% and the water content in gas I is not more than 5 wt%. The main activator is selected from at least one of water vapor, carbon dioxide, and oxygen.

[0018] In this invention, the volume concentrations mentioned are all based on the total volume of gas excluding protective gas (i.e., inert atmosphere).

[0019] This invention provides an activation process that utilizes the tail gas (rich in reducing gases) generated during the reaction for "self-inhibition," and its reaction principle is as follows: The main physical activation reaction is an endothermic and reversible reaction:

[0020]

[0021] According to the principles of chemical thermodynamics and kinetics, an increase in the partial pressure of reaction products (H2 and CO) will significantly inhibit the rate of forward gasification reaction. This invention increases the product concentration at the reaction interface by reinjecting tail gas containing high concentrations of H2 and CO, thereby reducing the gasification reaction rate of the carbon material. This causes the etching reaction to occur preferentially at the defect sites and pore edges of carbon, avoiding excessive ablation and collapse of the micropore walls, and achieving precise control of the micropore diameter.

[0022] Preferably, the activation reaction is controlled such that the volume concentration of the reducing gas in the reactor is 50-70 vol%. The inventors of this invention have discovered that, under this preferred condition, by reinjecting gas I containing high concentrations of H2 and CO, the product concentration at the reaction interface is increased, thereby reducing the gasification reaction rate of the carbide. This causes the etching reaction to preferentially occur at carbon defect sites and pore edges, avoiding excessive ablation and collapse of the micropore walls, and achieving precise control of the micropore diameter.

[0023] Preferably, the volumetric flow rate of gas I accounts for 20-50% of the total gas volumetric flow rate entering the reactor. In this preferred embodiment, the porous carbon provided by the present invention has an extremely narrow micropore distribution and a low surface oxygen content.

[0024] Preferably, the carbonaceous precursor is crushed and sieved to 100-300 mesh before undergoing the heat treatment.

[0025] Preferably, the heat treatment is a pre-oxidation treatment and / or a carbonization treatment.

[0026] Preferably, the pre-oxidation treatment conditions include: a temperature of 100-200℃ and a time of 60-180 min.

[0027] More preferably, the pre-oxidation treatment conditions include: selecting three temperatures within a temperature range of 100-200℃ for heating treatment, with each temperature having a treatment time of 20-60 minutes independently.

[0028] Preferably, the carbonization conditions include a temperature of 350-750℃ and a time of 30-60 minutes.

[0029] More preferably, the carbonaceous precursor is a heavy oil processing by-product; the heavy oil processing by-product is selected from at least one of petroleum coke, delayed coke, catalytic slurry, vacuum residue, or bitumen.

[0030] Preferably, the injection flow rate of the main activator is 0.5-2.0 L / min relative to 10g of the carbonized material.

[0031] In a preferred embodiment, the main activator is water vapor and carbon dioxide in a volume ratio of 1:1.

[0032] In a preferred embodiment, the heating rate is 5-10 °C / min.

[0033] Preferably, after the activation reaction has been carried out for 10-30 minutes, the gas I after the impurity removal and drying treatment is recycled back into the reactor.

[0034] In a preferred embodiment, the activation reaction conditions include: an activation temperature of 750-950°C and an activation time of 60-180 min.

[0035] Preferably, the reducing gas contains hydrogen and / or carbon monoxide.

[0036] According to one specific embodiment, the method for preparing the porous carbon based on physical activation includes: (1) The carbon precursor is subjected to pre-oxidation or carbonization treatment to obtain carbonized material; (2) Place the carbonized material in the reactor, heat it to the activation temperature under an inert atmosphere, and introduce the main activator to start the pore-forming reaction; The reaction tail gas containing reducing gases discharged from the reactor is collected, filtered, condensed and dehydrated, and then partially or completely mixed with fresh main activator and reinjected into the reactor to control the partial pressure of reducing gases in the reactor and maintain the activation reaction in a kinetically inhibited state until the reaction ends. After the reaction is completed and cooled, the porous carbon is obtained by washing and drying.

[0037] Preferably, the washing process includes: sequentially performing acid washing with dilute hydrochloric acid to remove ash and washing with deionized water 5-10 times.

[0038] Preferably, the drying conditions include a temperature of 100-130℃ and a time of 12-24h.

[0039] like Figure 3 As shown, according to one specific embodiment, the method for preparing the porous carbon based on physical activation includes: In a high-temperature activation reactor, carbonaceous precursor raw materials utilize steam, CO2, or oxygen as the main activator source. The exhaust gas (containing reducing components such as H2 and CO) generated during the activation reaction is recovered and purified through a tail gas purification and drying system before being reinjected into the reactor in a specific ratio via a regulating valve, creating an "in-situ self-suppressive" dynamic equilibrium atmosphere. This atmosphere, on the one hand, utilizes the principle of chemical equilibrium shift to reduce the ablation rate of the carbon material, achieving precise modification of the micropore size; on the other hand, it utilizes the reducing components to purify and deoxygenate the carbon framework in situ. The porous carbon product provided by this invention features an extremely narrow micropore distribution, high graphitization degree, and low surface oxygen content, making it suitable for applications in supercapacitors, lithium-ion battery anodes, and pollutant adsorption and degradation.

[0040] As previously stated, a second aspect of the present invention provides porous carbon prepared by the method described in the first aspect.

[0041] Preferably, the specific surface area of ​​the porous carbon is 950-2500 m². 2 / g, micropore volume ratio >60%, average pore size is 1.2-2.0 nm.

[0042] More preferably, the total pore volume of the porous carbon is 0.4-1.1 cm³. 3 / g, micropore volume is 0.35-0.80cm³ 3 / g, with a total oxygen content of 1.5-2.9wt%.

[0043] As previously stated, the third aspect of the present invention provides the application of the porous carbon described in the second aspect in the field of electrochemical energy storage devices or the environmental field.

[0044] Preferably, the electrochemical energy storage device is a supercapacitor electrode material and / or a lithium-sodium ion battery anode material.

[0045] Preferably, the environmental field is the field of pollutant adsorption and / or the field of electrocatalytic materials for pollutant degradation.

[0046] Preferably, the porous carbon, conductive agent, and binder are mixed and coated onto a current collector to form an electrode sheet. The electrode sheet can be assembled into a supercapacitor in an aqueous electrolyte or an organic electrolyte, and its specific capacitance and cycle stability are tested at current densities of 0.1-50 A / g.

[0047] Preferably, the conductive agent is acetylene black.

[0048] Preferably, the adhesive is polytetrafluoroethylene.

[0049] More preferably, the mass ratio of the porous carbon, the conductive agent, and the binder is 8:1:1.

[0050] Preferably, the porous carbon can be used for the adsorption of volatile organic compounds or as a cathode material for the electrocatalytic degradation of pollutants. For example, in adsorption tests, the porous carbon can be tested for its adsorption capacity for iodine, methylene blue, or low-concentration CO2; or in an electrocatalytic system, using the porous carbon as a gas diffusion electrode, its efficiency in degrading phenol wastewater by electroreducing oxygen to generate oxygen-active species can be tested.

[0051] The present invention will be described in detail below through embodiments. Unless otherwise specified, all instruments and materials used in the following embodiments are commercially available products.

[0052] The room temperature or normal temperature mentioned in this article means 25±2℃.

[0053] Heavy oil and petroleum coke: purchased from China Petroleum Jinzhou Petrochemical Company.

[0054] Dilute hydrochloric acid: concentration 10wt%.

[0055] Example 1 (1) Raw material processing: Heavy oil petroleum coke (i.e. carbonaceous precursor) is selected as raw material, crushed by a pulverizer and screened to obtain 200-mesh fine powder, and carbonized at 600℃ for 1 hour under nitrogen protection (i.e. heat treatment) to obtain carbonized material; (2) Activation process: Weigh 10 g of carbonized material and place it in a rotary kiln. Under N2 atmosphere (i.e., inert atmosphere), heat it to 850℃ (i.e. activation temperature) at a heating rate of 5℃ / min. Introduce pure water vapor (i.e., main activator, liquid water vaporization, injection flow rate of 1.0 L / min) to start the activation reaction. After reacting for 15 minutes, the tail gas circulation pump was turned on, and the reflux ratio was adjusted. The tail gas (i.e., gas I, with an H2 content of 65 vol% and a water content of 3 wt%) after condensation and dehydration was reinjected into the inlet at a flow rate of 300 mL / min to mix with fresh water vapor. The volume concentration of H2 (i.e., reducing gas) in the furnace atmosphere was controlled to be approximately 60 vol% and the gasification ablation rate was 0.5 wt% / min. This state was maintained for 90 minutes of activation. Post-processing: After stopping heating and shutting off circulation, the product was naturally cooled to room temperature under nitrogen protection. It was then washed with dilute hydrochloric acid to remove ash, washed with deionized water 8 times until neutral, and dried at 120℃ for 18 hours to obtain porous carbon.

[0056] Example 2 The process is the same as in Example 1, except that in this example, The main activator is carbon dioxide, and the injection flow rate is 500 mL / min; The exhaust gas after condensation and dehydration (i.e., gas I) contains 65% CO and 3% water. The volume concentration of CO (i.e., reducing gas) in the furnace atmosphere is controlled to be approximately 60 wt%; the gasification and ablation rate is 0.5 wt% / min. The remaining steps are the same as in Example 1, and porous carbon is obtained.

[0057] Example 3 The process is the same as in Example 1, except that in this example, The main activator is a mixture of water vapor and carbon dioxide (in a 1:1 ratio), and the injection flow rate is 500 mL / min. The exhaust gas after condensation and dehydration (i.e., gas I) contains 65% H2 and CO, and has a water content of 3 wt%. The volume concentrations of H2 and CO (i.e., reducing gases) in the furnace atmosphere were controlled to be approximately 60 wt%; the gasification ablation rate was 0.5 wt% / min. The remaining steps are the same as in Example 1, and porous carbon is obtained.

[0058] Example 4 The process is the same as in Example 1, except that in this example, The exhaust gas after condensation and dehydration (i.e., gas I, with an H2 content of 75% and a water content of 3%; the volumetric flow rate of gas I accounts for 55% of the total gas volumetric flow rate entering the reactor) The remaining steps are the same as in Example 1, and porous carbon is obtained.

[0059] Example 5 The process is the same as in Example 1, except that in this example, The volume concentration of H2 (i.e., reducing gas) in the furnace atmosphere was controlled to be approximately 45 wt%; the gasification ablation rate was 0.8 wt% / min. The remaining steps are the same as in Example 1, and porous carbon is obtained.

[0060] Example 6 The process is the same as in Example 1, except that in this example, The volume concentration of H2 (i.e., reducing gas) in the furnace atmosphere was controlled to be approximately 75 wt%; the gasification ablation rate was 0.3 wt% / min. The remaining steps are the same as in Example 1, and porous carbon is obtained.

[0061] Comparative Example 1 The same procedure as in Example 1 was used, except that tail gas recirculation was not performed in this comparative example. Specifically, (1) Raw material processing: Heavy oil petroleum coke (i.e. carbonaceous precursor) is selected as raw material, crushed by a pulverizer and screened to obtain 200-mesh fine powder, and carbonized at 600℃ for 1 hour under nitrogen protection to obtain carbonized material; (2) Activation process: Weigh 10 g of carbonized material and place it in a rotary kiln. Under N2 atmosphere (i.e., inert atmosphere), heat it to 850℃ (i.e. activation temperature) at a heating rate of 5℃ / min. Introduce pure water vapor (i.e., main activator, liquid water vaporization, injection flow rate of 1.0 L / min) to start the activation reaction. Maintain this state for 90 min. Post-processing: After natural cooling, the product was acid-washed with dilute hydrochloric acid to remove ash, washed 8 times with deionized water until neutral, and dried at 120℃ for 18 hours to obtain porous carbon.

[0062] Comparative Example 2 The process is the same as in Example 2, except that tail gas recirculation is not performed in this comparative example. Specifically, (1) Raw material processing: Heavy oil petroleum coke (i.e. carbonaceous precursor) is selected as raw material, crushed by a pulverizer and screened to obtain 200-mesh fine powder, and carbonized at 600℃ for 1 hour under nitrogen protection to obtain carbonized material; (2) Activation process: Weigh 10 g of carbonized material and place it in a rotary kiln. Under N2 atmosphere (i.e., inert atmosphere), heat it to 850℃ (i.e. activation temperature) at a heating rate of 5℃ / min. Introduce carbon dioxide (i.e., main activator, injection flow rate of 500mL / min) to start the activation reaction. Maintain this state for 90min. Post-processing: After natural cooling, the product was acid-washed with dilute hydrochloric acid to remove ash, washed 8 times with deionized water until neutral, and dried at 120℃ for 18 hours to obtain porous carbon.

[0063] Comparative Example 3 The same procedure as in Example 3 was used, except that tail gas recirculation was not performed in this comparative example. Specifically, (1) Raw material processing: Heavy oil petroleum coke (i.e. carbonaceous precursor) is selected as raw material, crushed by a pulverizer and screened to obtain 200-mesh fine powder, and carbonized at 600℃ for 1 hour under nitrogen protection to obtain carbonized material; (2) Activation process: Weigh 10 g of carbonized material and place it in a rotary kiln. Under N2 atmosphere (i.e., inert atmosphere), heat it to 850℃ (i.e., activation temperature) at a heating rate of 5℃ / min. Introduce a mixture of water vapor and carbon dioxide in a ratio of 1:1 (i.e., main activator, injection flow rate of 500 mL / min) to start the activation reaction. Maintain this state for 90 min. Post-processing: After natural cooling, the product was acid-washed with dilute hydrochloric acid to remove ash, washed 8 times with deionized water until neutral, and dried at 120℃ for 18 hours to obtain porous carbon.

[0064] Test case X-ray diffraction and Raman analysis were performed on the porous carbon obtained from petroleum coke in Examples 1-4 and Comparative Examples 1-3.

[0065] The Raman analysis method was as follows: a laser Raman spectrometer was used, with an excitation wavelength of 532 nm and a scanning range of 500-3500 cm⁻¹. -1 Through I D / I G The strength ratio is used to evaluate the degree of defects and graphitization level of a material.

[0066] Raman results Figure 1 As shown. By Figure 1 The results show that, in Examples 1-3, I D / I G The lower intensity ratio and sharper G peak indicate that the reducing components reinjected through the exhaust gas achieved in-situ purification and deoxidation of the carbon skeleton, significantly reducing structural defects and improving the degree of graphitization.

[0067] The X-ray diffraction analysis method is as follows: an X-ray diffractometer (XRD) is used with a Kα ray source, the scanning speed is 5° / min, and the scanning range 2θ is 10-70°.

[0068] The X-ray diffraction analysis results are shown below. Figure 2 As shown. By Figure 2 The results show that the 002 diffraction peaks near 2θ 26° in Examples 1-3 are clearer and have higher intensity than those in the comparative examples, proving that the excessive ablation of the pore walls is effectively avoided under the kinetic suppression atmosphere, and the orderly stacking of the porous carbon microcrystalline structure is maintained.

[0069] The BET specific surface area, yield, average pore size, total pore volume, elemental analysis, and electrical conductivity of the petroleum coke porous carbon obtained in the above embodiments and comparative examples were measured using a nitrogen adsorption-desorption apparatus. The test results are shown in Table 1.

[0070] The nitrogen adsorption-desorption method was as follows: a fully automated specific surface area and porosity analyzer was used to conduct nitrogen physical adsorption-desorption tests at 77 K. The specific surface area of ​​the sample was calculated using the BET equation, the total pore volume was taken as the adsorption amount at a relative pressure P / P0 = 0.99, and the pore size distribution was analyzed using the QSDFT model.

[0071] The formula for calculating yield is: Yield (%) = M 多孔碳 / M 碳前驱体 ×100%. Where M 多孔碳 For the final quality of the porous carbon, M 多孔碳 The mass of the original heavy oil processing byproducts.

[0072] The formula for calculating the percentage of micropore volume is: percentage of micropore volume (%) = micropore volume / total pore volume × 100%.

[0073] The elemental analysis method is as follows: the sample is accurately measured using an elemental analyzer under high-temperature combustion conditions, and the total oxygen content of the sample is directly measured by a thermal conductivity detector.

[0074] The conductivity measurement method is as follows: place the sample in a pressure powder resistivity tester and measure its ohmic value under a pressure of 10 MPa. Calculate the conductivity based on the cross-sectional area and thickness of the sample.

[0075] Table 1

[0076] Table 2

[0077] As shown in Table 1, Examples 1-3 using the tail gas recirculation reinjection process of this invention exhibited significantly higher porous carbon yields than Comparative Examples 1-3 (all yields were below 20%), which did not employ the reinjection process. Furthermore, the average pore size was successfully controlled within a narrow distribution range of 1.22-1.38 nm, effectively preventing excessive ablation and pore collapse of the micropores. Although Comparative Examples 1-3 possessed higher BET specific surface areas, the lack of a reducing gas's "self-inhibiting" effect led to excessively rapid gasification and ablation rates of the carbonized material, resulting in pore sizes generally increasing to 2.11 nm and above, with extremely low yields.

[0078] Furthermore, when the reinjection volume is too large (as in Example 4) or the concentration of reducing gas in the furnace is too high or too low (Examples 5 and 6), the average pore size increases to varying degrees or the yield decreases, demonstrating the key role of the specific reaction conditions described in this invention in controlling the pore size.

[0079] Further analysis based on the data in Table 2 shows that the electrical conductivity of the porous carbon prepared in Examples 1-3 remains at 2.82 Scm. -1 The results are significantly superior to those of Comparative Examples 1-3. This is attributed to the in-situ purification and deoxygenation of the carbon skeleton by the high concentration of H2 and CO in the exhaust gas at high temperatures, which reduces the content of oxygen-containing functional groups on the surface, thereby improving the conductivity of the material and making it more suitable for electrochemical energy storage fields such as batteries.

[0080] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing porous carbon based on physical activation, characterized in that, The method includes: (1) Heat-treat the carbonaceous precursor to obtain carbonized material; (2) Under an inert atmosphere, the temperature is raised to the activation temperature, and the main activator and the carbonized material are activated in a reactor to obtain the porous carbon. The conditions of the activation reaction are controlled such that the volume concentration of the reducing gas in the reactor is 15-75 wt%; and the gasification and ablation rate of the carbide is 0.3 wt% / min-1.0 wt% / min. The reaction tail gas obtained after the activation reaction is subjected to impurity removal and drying treatment to obtain gas I that can be recycled back to the reactor to participate in the activation reaction; the volumetric flow rate of gas I accounts for 10-60% of the total gas volumetric flow rate entering the reactor. The conditions for the impurity removal and drying process are controlled such that the content of reducing gas in gas I is not less than 50 wt% and the water content in gas I is not more than 5 wt%. The main activator is selected from at least one of water vapor, carbon dioxide, and oxygen.

2. The method according to claim 1, characterized in that, The activation reaction is controlled such that the volume concentration of the reducing gas in the reactor is 50-70% v%. And / or, the volumetric flow rate of gas I accounts for 20-50% of the total gas volumetric flow rate entering the reactor.

3. The method according to claim 1, characterized in that, The heat treatment is a pre-oxidation treatment and / or a carbonization treatment.

4. The method according to claim 3, characterized in that, The pre-oxidation treatment conditions include: a temperature of 100-200℃ and a time of 60-180 min; And / or, the carbonization treatment conditions include: a temperature of 350-750°C and a time of 30-60 min.

5. The method according to claim 1, characterized in that, The carbonaceous precursor is a byproduct of heavy oil processing; the heavy oil processing byproduct is selected from at least one of petroleum coke, delayed coke, catalytic slurry, vacuum residue, or bitumen.

6. The method according to any one of claims 1-5, characterized in that, The injection flow rate of the main activator is 0.5-2.0 L / min; And / or, the heating rate is 5-10 °C / min; And / or, the activation reaction conditions include: an activation temperature of 750-950℃ and an activation time of 60-180 min.

7. The method according to any one of claims 1-5, characterized in that, The reducing gas contains hydrogen and / or carbon monoxide.

8. Porous carbon prepared by the method according to any one of claims 1-7.

9. The porous carbon according to claim 8, characterized in that, The specific surface area of ​​the porous carbon is 950-2500 m². 2 / g, micropore volume ratio >60%, average pore size is 1.2-2.0 nm.

10. The application of the porous carbon according to claim 8 or 9 in the field of electrochemical energy storage devices or the environmental field.

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