N and P co-doped porous carbon based on enteromorpha as well as preparation method and application of N and P co-doped porous carbon

Abstract

The invention discloses N and P co-doped porous carbon based on enteromorpha as well as a preparation method and application of the N and P co-doped porous carbon. Biomass and a chemical activator are uniformly mixed by using a microwave-assisted pre-oxidation treatment means, and oxygen-containing functional groups are introduced into the surface and pore structure of a carbon material, so that the specific surface area of a porous carbon product is increased, the temperature in the carbonization process is reduced, and the problem that the pore structure of the carbon material is easy to collapse and damage at a high temperature is solved; an ultrasonic treatment means is used for pickling, so that the problem that impurities and an activating agent are not thoroughly removed is effectively solved; the P element is doped in the phosphoric acid impregnation process, the enteromorpha contains rich N element, and the conductivity of the porous carbon can be effectively improved through co-doping of N and P.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon material preparation, and in particular to N and P co-doped porous carbon based on enteromorpha, and a preparation method and application thereof. Background Art

[0002] The excessive growth of marine algae such as Enteromorpha has seriously affected the local marine ecological environment and ecological service functions, causing huge economic losses. In 2008 alone, the direct losses and removal costs caused by the green tide in Qingdao amounted to 1.3 billion yuan. The green tide has gradually evolved into a normalized marine disaster in the Yellow Sea of ​​my country. At present, biomass raw materials are one of the important carbon sources for the preparation of porous carbon materials. Therefore, using algae biomass such as Enteromorpha as raw materials and preparing high-value porous carbon materials through technical means is a way to "turn waste into treasure". There are many traditional methods for preparing bio-based porous carbon, including high-temperature carbonization, activation, acid leaching and pickling, which have problems such as high cost, uneven pore size distribution, low biomass utilization, unfavorable large-scale production, and poor properties of carbon material products. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention provides an N, P co-doped porous carbon based on Enteromorpha, and a preparation method and application thereof.

[0005] In a first aspect, the present invention provides a method for preparing N and P co-doped porous carbon based on Enteromorpha, comprising the following steps:

[0006] (a) subjecting Enteromorpha powder and an activator to microwave-assisted preoxidation treatment in a high-temperature microwave device to obtain preoxidized powder;

[0007] (b) adding a phosphoric acid solution into deionized water in which the pre-oxidized powder is dispersed, and then freeze-drying the mixture to obtain a biomass precursor;

[0008] (c) carbonizing the biomass precursor in an inert gas to obtain a carbonized sample;

[0009] (d) dispersing the carbonized sample into a pickling solution and performing ultrasonic-assisted pickling to obtain a pickled sample.

[0010] Furthermore, the method also includes washing and vacuum drying the acid-washed sample in step (e) to obtain a porous carbon sample.

[0011] Furthermore, the enteromorpha powder is obtained by grinding and sieving the washed and dried enteromorpha.

[0012] Furthermore, the activator is bicarbonate, and the bicarbonate includes one or both of NaHCO3 and KHCO3.

[0013] Furthermore, the high-temperature microwave equipment includes one of a microwave sintering furnace, a microwave tube furnace, a microwave ashing furnace, and a microwave reactor.

[0014] Furthermore, the power of the high-temperature microwave equipment is above 1000W.

[0015] Furthermore, the carbonization temperature of the carbonization treatment in step (c) is 500-900° C., and the carbonization time is 1-3 hours.

[0016] Furthermore, the pickling solution in step (d) includes at least one of hydrochloric acid, nitric acid and sulfuric acid.

[0017] Furthermore, in step (d), the ultrasonic-assisted pickling time is 5 to 20 minutes.

[0018] In a second aspect, the present invention proposes porous carbon prepared by the method proposed in the first aspect of the present invention.

[0019] In a third aspect, the present invention proposes the use of the porous carbon prepared by the preparation method proposed in the first aspect of the present invention or the porous carbon proposed in the second aspect of the present invention in catalyst carriers, hydrogen storage materials, and electrode materials.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The present invention utilizes microwave-assisted pre-oxidation treatment to uniformly mix biomass and chemical activators, introduces oxygen-containing functional groups on the surface and in the pore structure of carbon materials, increases the specific surface area of ​​porous carbon products, reduces the temperature of the carbonization process, and solves the problem that the pore structure of carbon materials is prone to collapse and damage at high temperatures; utilizes ultrasonic treatment to perform acid washing, effectively solving the problem of incomplete removal of impurities and activators; and incorporates P elements through a phosphoric acid impregnation process. Enteromorpha itself is rich in N elements, and co-doping of N and P can effectively improve the conductivity of porous carbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0023] Figure 1 This is a flow chart of the preparation method of high-stability mesoporous carbon of the present invention;

[0024] Figure 2 This is a flowchart of the method for preparing high-stability mesoporous carbon of the present invention;

[0025] Figure 3The present invention is a flow chart of the method for preparing the catalyst;

[0026] Figure 4 A low-magnification scanning electron microscope image of the porous carbon prepared in Example 1 of the present invention;

[0027] Figure 5 A high-magnification scanning electron microscope image of the porous carbon prepared in Example 1 of the present invention;

[0028] Figure 6 A low-magnification transmission electron microscopy image of the porous carbon prepared in Example 1 of the present invention;

[0029] Figure 7 A high-magnification transmission electron microscopy image of the porous carbon prepared in Example 1 of the present invention;

[0030] Figure 8 This is an EDS element mapping diagram of the porous carbon prepared in Example 1 of the present invention;

[0031] Fig. 9 The infrared spectrum of the porous carbon prepared in Example 1 of the present invention;

[0032] Fig.10 The X-ray photoelectron spectrum of the porous carbon prepared in Example 1 of the present invention;

[0033] Fig.11 X-ray diffraction spectrum of porous carbon prepared in Example 1 of the present invention

[0034] Fig.12 The Raman spectrum of the porous carbon prepared in Example 1 of the present invention;

[0035] Fig.13 It is a N2 adsorption-desorption constant temperature curve diagram of the porous carbon prepared in Example 1, Comparative Examples 1 and 2 of the present invention;

[0036] Fig.14 The BET pore size distribution diagram of the porous carbon prepared in Example 1 of the present invention;

[0037] Fig.15 The cyclic voltammetry curves of the catalysts prepared from porous carbon of Example 1 and Comparative Example 2 of the present invention are shown;

[0038] Fig.16 Polarization curves of catalysts prepared from porous carbon according to Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0040] The following describes a method for preparing N and P co-doped porous carbon based on Enteromorpha according to an embodiment of the present invention with reference to the accompanying drawings.

[0041] like Figure 1 and Figure 2 As shown, the preparation method of N and P co-doped porous carbon based on Enteromorpha of the present invention comprises the following steps:

[0042] (a) subjecting Enteromorpha powder and an activator to microwave-assisted preoxidation treatment in a high-temperature microwave device to obtain preoxidized powder;

[0043] (b) adding a phosphoric acid solution into deionized water in which the pre-oxidized powder is dispersed, and then freeze-drying the mixture to obtain a biomass precursor;

[0044] (c) carbonizing the biomass precursor in an inert gas to obtain a carbonized sample;

[0045] (d) dispersing the carbonized sample into a pickling solution, and performing ultrasonic-assisted pickling to obtain a pickled sample;

[0046] (e) The acid-washed sample is washed and vacuum-dried to obtain a porous carbon sample.

[0047] In step (a), the Enteromorpha powder is obtained by grinding and sieving the washed and dried Enteromorpha. Specifically, fresh Enteromorpha is naturally obtained from the ocean, washed with distilled water to remove excess seawater, and then dried; after drying, an appropriate amount of Enteromorpha is weighed and ground and crushed in an agate mortar, and the Enteromorpha powder is sieved through a 150-mesh standard sieve.

[0048] The activator is bicarbonate, and the bicarbonate includes one or both of NaHCO3 and KHCO3. The mass ratio of Enteromorpha powder to bicarbonate is 1:1 to 1:5. In some embodiments, the mass ratio of Enteromorpha powder to bicarbonate is 1:1, 1:2, 1:3, 1:4, 1:5, or a value within a range consisting of any two values.

[0049] During microwave-assisted pre-oxidation treatment, enteromorpha powder and bicarbonate are placed in a crucible, and then the crucible is placed in a high-temperature microwave device, and microwave-assisted pre-oxidation treatment is performed for 0.5 to 1.5 hours at a power of more than 1000W in an air atmosphere to ensure complete pre-oxidation. Pre-oxidation treatment is performed by microwave-assisted technology to introduce oxygen-containing functional groups on the surface and pore structure of carbon materials, effectively reducing the carbonization temperature and increasing the specific surface area and stability.

[0050] In some embodiments, the power of the high temperature microwave device is 1000 W, 1500 W, 1800 W, 2000 W or other suitable values. The high temperature microwave device includes one of a microwave sintering furnace, a microwave tube furnace, a microwave ashing furnace and a microwave reactor.

[0051] In step (b), the mass ratio of Enteromorpha powder to the solute in the phosphoric acid solution is 1:1 to 1:4. In some embodiments, the mass ratio of Enteromorpha powder to the solute in the phosphoric acid solution is 1:1, 1:2, 1:3, 1:4, or a value within a range consisting of any two values. The mass concentration of the phosphoric acid solution is 40% to 60%. In some embodiments, the mass concentration of the phosphoric acid solution is 40%, 50%, 60%, or a value within a range consisting of any two values.

[0052] The purpose of impregnation with phosphoric acid solution is to dope P element. Enteromorpha itself contains rich N element. N and P co-doping can effectively improve the conductivity of porous carbon. The specific process is to first disperse the pre-oxidized powder into deionized water, then add phosphoric acid solution, acid impregnate for more than 2 hours, and then dry in a freeze dryer for more than 48 hours.

[0053] The carbonization temperature of the carbonization treatment described in step (c) is 500°C to 900°C, and the carbonization time is 1 to 3 hours to ensure that the biomass is completely carbonized. The inert gas is nitrogen or argon, and the flow rate of the inert gas during the carbonization process is 15 to 30 mL / min. In some embodiments, the carbonization temperature is 500°C, 600°C, 700°C, 800°C, 900°C, or a value within the range of any two numerical values. In some embodiments, the carbonization time is 1h, 2h, 3h, or a value within the range of any two numerical values.

[0054] Step (d) is an ultrasonic-assisted pickling process, and the specific process is that after the carbonization is completed and cooled to room temperature, the carbonized sample is dispersed in the pickling solution, stirred and mixed evenly to form a slurry, and the slurry is subjected to ultrasonic-assisted pickling treatment for 5 to 20 minutes at a power of more than 300 W in an air atmosphere. The pickling by ultrasound effectively solves the problem of incomplete removal of impurities and activators.

[0055] In some embodiments, the pickling solution includes at least one of hydrochloric acid, nitric acid, and sulfuric acid. It is understandable that the pickling solution may also be other suitable acidic solutions.

[0056] In some embodiments, the ultrasonic assisted pickling time is 5 min, 10 min, 15 min, 20 min, or a value within a range consisting of any two values.

[0057] In some embodiments, the ultrasonic assisted pickling power is 300 W, 500 W, 700 W, 900 W or other suitable values.

[0058] The porous carbon of the present invention is prepared by the preparation method of the N and P co-doped porous carbon based on Enteromorpha of the present invention.

[0059] The porous carbon of the present invention can be applied to catalyst carriers, hydrogen storage materials and electrode materials.

[0060] In some embodiments, the porous carbon of the present invention is used as a catalyst support, such as Figure 3 As shown, the preparation method of the catalyst comprises the following steps:

[0061] The porous carbon is dispersed into an ethanol solution, and a noble metal precursor is added and mixed evenly;

[0062] A reducing agent and a charged surfactant are added, and a reduction reaction is performed with the assistance of ultrasound. The catalyst sample is washed by centrifugation and dried in vacuum to obtain the catalyst sample.

[0063] The porous carbon is the porous carbon proposed in the present invention or the porous carbon prepared by the preparation method of N and P co-doped porous carbon based on Enteromorpha in the present invention. The mass fraction of the ethanol solution is 1% to 30%. In some embodiments, the mass fraction of the ethanol solution is 1%, 5%, 10%, 15%, 20%, 25%, 30% or a value within the range of any two values.

[0064] The noble metal precursor includes a precursor of platinum, gold, iridium, or rubidium, for example, chloroplatinic acid, chloroauric acid, chloroiridic acid, or other suitable noble metal precursors. The mass fraction of the noble metal precursor is 20% to 80%. In some embodiments, the mass fraction of the noble metal precursor is 20%, 40%, 60%, 80%, or a value within a range consisting of any two values.

[0065] The reducing agent includes one or more of HCHO, HCOONa, Na2SO3, and NaBH4; the charged surfactant includes one or more of quaternary ammonium salt, PPh3, PVP, and PVA, wherein PPh3 is triphenylphosphine, PVP is polyvinyl pyrrolidone, and PVA is polyvinyl alcohol.

[0066] The ultrasonic power is 50W, 100W, 200W or other suitable values. After the reduction reaction is completed, the product is washed by centrifugation for multiple times and vacuum dried at 60°C to 80°C for 8 to 12 hours to ensure that the drying is complete. Deionized water and / or ethanol solution are used for washing the product.

[0067] Example 1

[0068] (1) Fresh Enteromorpha was washed with distilled water to remove excess seawater and then dried. Then 100 g of the dried Enteromorpha was weighed and ground in an agate mortar for 30 min. Enteromorpha powder was sieved through a 150-mesh standard sieve. 1 g of Enteromorpha powder, 1 g of NaHCO3, and 2 g of KHCO3 were weighed and put into a crucible, placed in a microwave reactor, and microwave-assisted pre-oxidation was performed at a power of 1500 W for 1 h to obtain pre-oxidized powder.

[0069] (2) adding the oxidized pre-powder into 20 mL of distilled water, and then adding phosphoric acid with a mass concentration of 50%, the mass ratio of the powder to the solute in the phosphoric acid solution being 1:1.2, and then drying in a freeze dryer for 48 hours to obtain a biomass precursor;

[0070] (3) The obtained biomass precursor was placed in a high-temperature tube furnace, N2 atmosphere, carbonized and activated at 700°C, with a heating rate of 3°C / min and a N2 flow rate of 20 mL / min. After carbonization for 2 h, it was cooled to room temperature to obtain a carbonized sample;

[0071] (4) The carbonized sample was placed in a 50 mL beaker, and 40 mL of a 2 mol / L HCl solution was added. The mixture was stirred and mixed evenly. The slurry was subjected to ultrasonic-assisted pickling treatment for 15 min at a power of 300 W. The pickled sample was washed with an ethanol aqueous solution for multiple times until the pH value became 6 to remove residual activators and impurities, and then vacuum dried at 60 ° C for 12 h to obtain a porous carbon sample.

[0072] Comparative Example 1

[0073] (1) Wash the fresh Enteromorpha with distilled water to remove excess seawater and then dry it. Then weigh 100 g of the dried Enteromorpha and grind it in an agate mortar for 30 min. Then sieve the Enteromorpha powder through a 150-mesh standard sieve.

[0074] (2) Adding Enteromorpha powder to 20 mL of distilled water, and then adding phosphoric acid with a mass concentration of 50%, the mass ratio of the powder to the solute in the phosphoric acid solution is 1:1.2, and then drying in a freeze dryer for 48 hours to obtain a biomass precursor;

[0075] (3) The obtained biomass precursor was placed in a high-temperature tube furnace, N2 atmosphere, carbonized and activated at 700°C, with a heating rate of 3°C / min and a N2 flow rate of 20 mL / min. After carbonization for 2 h, it was cooled to room temperature to obtain a carbonized sample;

[0076] (4) The carbonized sample was placed in a 50 mL beaker, and 40 mL of a 2 mol / L HCl solution was added. The mixture was stirred and mixed evenly. The slurry was subjected to ultrasonic-assisted pickling treatment for 15 min at a power of 300 W. The pickled sample was washed with an ethanol aqueous solution for multiple times until the pH value became 6 to remove residual activators and impurities, and then vacuum dried at 60 ° C for 12 h to obtain a porous carbon sample.

[0077] Comparative Example 2

[0078] (1) Fresh Enteromorpha was washed with distilled water to remove excess seawater and then dried. Then 100 g of the dried Enteromorpha was weighed and ground in an agate mortar for 30 min. Enteromorpha powder was sieved through a 150-mesh standard sieve. 1 g of Enteromorpha powder, 1 g of NaHCO3, and 2 g of KHCO3 were weighed and put into a crucible, placed in a microwave reactor, and microwave-assisted pre-oxidation was performed at a power of 1500 W for 1 h to obtain pre-oxidized powder.

[0079] (2) adding the oxidized pre-powder into 20 mL of distilled water, and then drying in a freeze dryer for 48 h to obtain a biomass precursor;

[0080] (3) The obtained biomass precursor was placed in a high-temperature tube furnace, N2 atmosphere, carbonized and activated at 700°C, with a heating rate of 3°C / min and a N2 flow rate of 20 mL / min. After carbonization for 2 h, it was cooled to room temperature to obtain a carbonized sample;

[0081] (4) The carbonized sample was placed in a 50 mL beaker, and 40 mL of a 2 mol / L HCl solution was added. The mixture was stirred and mixed evenly. The slurry was subjected to ultrasonic-assisted pickling treatment for 15 min at a power of 300 W. The pickled sample was washed with an ethanol aqueous solution for multiple times until the pH value became 6 to remove residual activators and impurities, and then vacuum dried at 60 ° C for 12 h to obtain a porous carbon sample.

[0082] Test Example 1

[0083] The porous carbon prepared in Example 1 was tested by low-magnification scanning electron microscopy, high-magnification scanning electron microscopy, low-magnification transmission electron microscopy and high-magnification transmission electron microscopy, respectively. The results are as follows: Figures 4 to 7 As shown in the figure, it can be seen that the porous carbon sample presents an ordered porous morphology structure with a uniform pore size structure and belongs to the mesoporous size, which is conducive to the subsequent preparation of hydrogen fuel cell catalysts and provides more reaction active sites for redox reactions.

[0084] Test Example 2

[0085] The porous carbon prepared in Example 1 was subjected to EDS analysis test, and the results are as follows: Figure 8 As shown, it can be seen from the figure that the porous carbon contains elements such as C, O, N, and P, and the porous carbon prepared by the present invention has successfully incorporated N and P elements.

[0086] The porous carbon prepared in Example 1 was tested by infrared spectroscopy. The results are as follows: Fig. 9 As shown, it can be seen from the figure that the porous carbon contains vibration peaks such as C=C, C=O, CN, CP, etc., indicating that the material contains elements such as N and P.

[0087] The porous carbon prepared in Example 1 was tested by X-ray photoelectron spectroscopy. The results are as follows: Fig.10 As shown, it can be seen from the figure that the porous carbon has obvious C1s, O1s, N2p, and P2p related peaks, indicating that the porous carbon structure prepared by the present invention is doped with N and P elements.

[0088] Test Example 3

[0089] The porous carbon prepared in Example 1 was subjected to an X-ray diffraction test, and the test results are as follows: Fig.11 As shown, it can be seen from the figure that porous carbon has obvious (002) and (100) diffraction peaks, indicating that porous carbon is an amorphous material, and amorphous materials have unique properties such as isotropy, defect distribution, and structural flexibility.

[0090] The porous carbon prepared in Example 1 was tested by Raman spectroscopy. Fig.12 As shown in the figure, it can be seen that the porous carbon has obvious D and G peaks, I D / I G The value is 1.21, indicating that the porous carbon material has very high porosity and rich defect density.

[0091] Test Example 4

[0092] The porous carbon prepared in Example 1, Comparative Example 1 and Comparative Example 2 was subjected to nitrogen adsorption and desorption tests. The test results are as follows: Fig.13 As shown in the figure, it can be seen that the porous carbon prepared in Example 1 of the present invention has the highest specific surface area of ​​679.9 m 3 / g, the specific surface areas of the products obtained in Comparative Example 1 and Comparative Example 2 were 468.9m 3 / g and 644.0m 3 / g, indicating that the samples obtained after microwave-assisted pre-oxidation treatment have better pore structure and specific surface area.

[0093] Test Example 5

[0094] The pore size distribution and thermal stability of the porous carbon samples prepared in Example 1, Comparative Example 1 and Comparative Example 2 were tested respectively. The test results are shown in Table 1 and Fig.14 As shown, Fig.14 This is a pore size distribution curve of the porous carbon prepared in Example 1.

[0095] <![CDATA[Specific surface area (m 3 / g)]]> Average pore size (nm) Thermal stability(℃) Example 1 679.9 22.7 ＞500 Comparative Example 1 468.9 31.0 ＞450 Comparative Example 2 644.0 23.1 ＞500

[0096] According to the above table, the porous carbon prepared in Example 1 has a higher specific surface area than that in Comparative Example 1 and Comparative Example 2, and the porous carbon prepared in Example 1 has a higher thermal stability.

[0097] Test Example 6

[0098] Catalysts were prepared using the porous carbon prepared in Example 1, Comparative Example 1 and Comparative Example 2 as carriers, and the prepared catalysts were used as anode catalysts to prepare membrane electrodes.

[0099] The specific preparation process of the catalyst is as follows: weigh 500 mg of the porous carbon sample, disperse it in 100 ml of a 50% ethanol-water solution, add 335 mg of chloroplatinic acid, and stir to dissolve and mix for 20 minutes; then add 1 g of NaBH4 reducing agent and an appropriate amount of 0.5 g of charged surfactant PVA; carry out a reduction reaction with the assistance of 200 W ultrasonic waves to prepare a porous carbon@Pt catalyst, wash it by centrifugation with deionized water three times, and vacuum dry it at 60°C for 12 hours to obtain a catalyst sample.

[0100] The specific preparation process of the working electrode is as follows: 5 mg of catalyst is weighed with an electronic balance, 45 mg of 5% Nafion, 3 ml of ultrapure water, and 3 ml of isopropanol are added to the catalyst, and then ultrasonicated with a power of 300 W for 30 min to fully mix the slurry. During the ultrasonication process, the water bath temperature is maintained at about 20 ° C; according to the range of the catalyst loading on the electrode surface of 100 μg / cm 2 , take an appropriate amount of the dispersed slurry and evenly apply it to the smooth and clean surface of the disk electrode twice, and let it dry completely naturally as the working electrode.

[0101] The membrane electrode prepared by using the catalyst of the porous carbon as the carrier of Example 1 and Comparative Example 2 was used as the working electrode. At 25°C, in the three-electrode system, 0.1 mol / L HClO4 saturated with N2 was used as the electrolyte, and the temperature was 0-1.2 V. RHE Scanning range, 50mV / s speed rate, test cyclic voltammetry performance. Test results are as follows Fig.15 As shown in the figure, it can be seen that the precious metal catalysts prepared in Example 1 and Comparative Example 2 both have obvious redox catalytic performance, but the catalyst oil prepared in Example 1 has a larger electrochemical active area than that prepared in Comparative Example 2. The experimental results show that the porous carbon material doped with P element has better electrical conductivity and has a better catalytic effect in the catalytic reaction process.

[0102] The membrane electrode prepared by using the catalyst of the porous carbon as the carrier of Example 1 and Comparative Example 1 as the working electrode, high O2 was introduced into the 0.1 mol / L HCIO4 aqueous solution, and the purge was carried out for at least 30 min to achieve oxidation saturation; in the three-electrode system, at 25 ° C, the ring electrode speed was 1500 r / min, and the temperature was between 0.2 and 1.2 V. RHE In the potential scanning range, scan forward at a speed of 10mV / s and record the polarization curve and 0.9V RHE The test results are as follows: Fig.16 As shown in the figure, it can be seen that the catalyst prepared with the porous carbon as the carrier in Example 1 has a RHE 5.23mA / cm 2 Current density, while Comparative Example 1 at 0.9V RHE Only 2.69mA / cm 2 The experimental results show that after microwave-assisted pre-oxidation treatment, oxygen-containing functional groups can be introduced into the porous carbon and the specific surface area can be increased, so that the corresponding porous carbon-based catalyst has stronger catalytic activity.

[0103] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", "some examples", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms may be for different embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0104] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0105] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing N and P co-doped porous carbon based on Enteromorpha, characterized in that: The following steps are involved: (a) subjecting Enteromorpha powder and an activator to microwave-assisted preoxidation treatment in a high-temperature microwave device to obtain preoxidized powder; (b) adding a phosphoric acid solution into deionized water in which the pre-oxidized powder is dispersed, and then freeze-drying the mixture to obtain a biomass precursor; (c) carbonizing the biomass precursor in an inert gas to obtain a carbonized sample; (d) dispersing the carbonized sample into a pickling solution and performing ultrasonic-assisted pickling to obtain a pickled sample.

2. The preparation method according to claim 1, characterized in that The step also includes washing and vacuum drying the acid-washed sample to obtain a porous carbon sample.

3. The preparation method according to claim 1, characterized in that: The enteromorpha powder is obtained by grinding and sieving the washed, dried enteromorpha.

4. The preparation method according to claim 1, characterized in that: The activator is bicarbonate, and the bicarbonate includes one or two of NaHCO3 and KHCO3.

5. The preparation method according to claim 1, characterized in that: The high-temperature microwave equipment includes one of a microwave sintering furnace, a microwave tube furnace, a microwave ashing furnace, and a microwave reactor. The power of the high-temperature microwave equipment is above 1000W.

6. The preparation method according to claim 1, characterized in that: The carbonization temperature of the carbonization treatment in step (c) is 500-900° C., and the carbonization time is 1-3 hours.

7. The preparation method according to claim 1, characterized in that: The pickling solution in step (d) includes at least one of hydrochloric acid, nitric acid and sulfuric acid.

8. The preparation method according to claim 1, characterized in that: The ultrasonic-assisted pickling time in step (d) is 5 to 20 minutes.

9. A porous carbon, characterized in that: The method is prepared by any one of claims 1 to 8.

10. Use of the porous carbon prepared by the preparation method according to any one of claims 1 to 8 or the porous carbon according to claim 9 in catalyst carriers, hydrogen storage materials and electrode materials.

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