CN110854395A - Preparation method and application of nitrogen-doped porous biomass carbon - Google Patents
Preparation method and application of nitrogen-doped porous biomass carbon Download PDFInfo
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- CN110854395A CN110854395A CN201911187871.8A CN201911187871A CN110854395A CN 110854395 A CN110854395 A CN 110854395A CN 201911187871 A CN201911187871 A CN 201911187871A CN 110854395 A CN110854395 A CN 110854395A
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- H—ELECTRICITY
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Abstract
The application belongs to the field of fuel cell electro-catalytic materials, and particularly relates to a preparation method and application of nitrogen-doped porous biomass carbon. The preparation method provided by the invention comprises the following steps: sequentially adding the biomass chitosan in inert gas and CO2And NH3Carrying out pyrolysis in the atmosphere to obtain nitrogen-doped porous biomass carbon; wherein in the presence of inert gas, CO2And NH3The temperature rise rate of the pyrolysis in the atmosphere is 3-7 ℃/min, 8-15 ℃/min and 8-15 ℃/min in sequence, the temperature rise end point temperature is 400-600 ℃, 700-800 ℃ and 700-900 ℃ in sequence, and the heat preservation time is 1-3 h, 1-8 h and 1-8 h in sequence. According to the invention, by optimally designing the appropriate pyrolysis temperature and pyrolysis atmosphere, the prepared nitrogen-doped porous biomass carbon has very excellent electrocatalytic oxygen reduction performance, stability and methanol resistance, and has a wide application prospect in the field of electrocatalytic materials of fuel cells.
Description
Technical Field
The invention belongs to the field of electrocatalytic materials of fuel cells, and particularly relates to a preparation method and application of nitrogen-doped porous biomass carbon.
Background
With the increasing environmental pollution problem and the increasing consumption of traditional fossil fuels, the development of clean, efficient and sustainable energy becomes an important research topic for today's scientists. The fuel cell is a device capable of directly converting chemical energy of fuel into electric energy, has the advantages of high energy conversion efficiency, rich fuel source, low pollution and the like, and becomes a novel green energy technology with the greatest development prospect. Nowadays, with the rapid development of new energy automobile industry, people are urgently needed to develop a green, environment-friendly, economical and practical high-performance fuel cell for automobile power. Among them, the electrocatalyst is a key part of the fuel cell, and the current electrocatalyst for cathode oxygen reduction reaction in the fuel cell is mainly based on the noble metal platinum-based catalyst, but unfortunately, the platinum has limited reserves on the earth, is expensive at scrupulously and respectfully, and has a large loading on the cathode. In addition, platinum-based materials are limited by other factors, such as reduced performance and poor stability due to methanol poisoning, which greatly impede the commercialization of fuel cells. Therefore, the composite material electrocatalyst which is low in preparation cost and has good catalytic activity, stability and methanol resistance has important significance for rapidly realizing large-scale commercial application of fuel cells.
In recent years, with the continuous development of material science, more and more carbon materials with high electrochemical performance are reported, such as graphene, carbon nanotubes, ultrathin carbon nanosheets, super conductive carbon black, hollow carbon spheres and the like. These carbon materials can be directly applied to the cathode reaction of a fuel cell by using the doping atoms N, S, P and B as an electrocatalyst, and can also be used as a carrier for some metals, metal oxides, metal sulfides and the like. At present, the electrocatalytic oxygen reduction performance of some non-noble metal doped carbon materials exceeds that of a platinum-based catalyst, the price of the platinum-based catalyst is lower than that of platinum, but the price of the platinum-based catalyst is still higher, and the preparation process is complex and is not suitable for large-scale commercial application.
Nearly 1400 billion worldwide of waste biomass from agriculture and forestry every year, and how to make reasonable use of this biomass has become a research hotspot. Compared with other carbon materials which are still in research level, the preparation process of the biomass carbon is simple, low in cost and sustainable. Therefore, the development of a biomass carbon material suitable for use as a fuel cell catalyst is of great importance in the realization of recycling of waste biomass and large-scale commercialization of fuel cells.
Disclosure of Invention
In view of the above, the invention aims to provide a preparation method and application of nitrogen-doped porous biomass carbon, and the nitrogen-doped porous biomass carbon prepared by the method has excellent electrocatalytic oxygen reduction performance, stability and methanol resistance, and has a wide application prospect in the field of electrocatalytic materials of fuel cells.
The invention provides a preparation method of nitrogen-doped porous biomass carbon, which comprises the following steps:
sequentially placing the biomass chitosan in inert gas atmosphere and CO2Atmosphere and NH3Carrying out pyrolysis in the atmosphere to obtain nitrogen-doped porous biomass carbon;
wherein the heating rate of pyrolysis in the inert gas atmosphere is 3-7 ℃/min, the temperature of the heating end point is 400-600 ℃, and the heat preservation time is 1-3 h;
in the CO2The temperature rise rate of pyrolysis in the atmosphere is 8-15 ℃/min, the temperature rise end point temperature is 700-800 ℃, and the heat preservation time is 1-8 h;
in the NH3The temperature rise rate of pyrolysis in the atmosphere is 8-15 ℃/min, the temperature rise end point temperature is 700-900 ℃, and the heat preservation time is 1-8 h.
Preferably, the heating rate of the pyrolysis in the inert gas atmosphere is 5-6 ℃/min, the temperature of the heating end point is 500-550 ℃, and the heat preservation time is 2-2.5 h.
Preferably, in said CO2The temperature rise rate for pyrolysis in the atmosphere is 10-12 ℃/min.
Preferably, in said NH3The temperature rise rate for pyrolysis in the atmosphere is 10-12 ℃/min.
Preferably, the relative molecular mass of the biomass chitosan is 300000-1000000 Da.
Preferably, the particle size of the biomass chitosan is more than 400 meshes.
Preferably, the biomass chitosan is dried and ball milled before being pyrolyzed.
Preferably, the drying temperature is 70-90 ℃; the drying time is 12-48 h;
the diameter of the grinding body of the ball mill is 2-4 mm; the rotating speed of the ball mill is 400-600 revolutions per minute; the ball milling time is 10-20 h.
The invention provides catalyst ink which comprises a catalyst and a membrane solution, wherein the catalyst comprises nitrogen-doped porous biomass carbon prepared by the preparation method in the technical scheme.
The invention provides a fuel cell, and a catalyst adopted by the fuel cell comprises nitrogen-doped porous biomass carbon prepared by the preparation method in the technical scheme.
Compared with the prior art, the invention provides a preparation method and application of nitrogen-doped porous biomass carbon. The preparation method provided by the invention comprises the following steps: sequentially placing the biomass chitosan in inert gas atmosphere and CO2Atmosphere and NH3Carrying out pyrolysis in the atmosphere to obtain nitrogen-doped porous biomass carbon; wherein the heating rate of pyrolysis in the inert gas atmosphere is 3-7 ℃/min, the temperature of the heating end point is 400-600 ℃, and the heat preservation time is 1-3 h; in the CO2The temperature rise rate of pyrolysis in the atmosphere is 8-15 ℃/min, the temperature rise end point temperature is 700-800 ℃, and the heat preservation time is 1-8 h; in the NH3The temperature rise rate of pyrolysis in the atmosphere is 8-15 ℃/min, the temperature rise end point temperature is 700-900 ℃, and the heat preservation time is 1-8 h. According to the preparation method provided by the invention, proper pyrolysis temperature and pyrolysis atmosphere are optimally designed, so that biomass chitosan is firstly pyrolyzed into biomass carbon coarse material in inert gas atmosphere; then passing through CO2The biomass carbon coarse material is etched by violent reaction with carbon, so that the biomass carbon coarse material generates a large amount of microporous structures, and the surface area of the biomass carbon coarse material is increased; thereafter using NH3And weak reaction with carbon is continuously carried out, so that the surface area and the pore structure of the biomass carbon coarse material are further improved, and nitrogen supplement is carried out on the biomass carbon coarse material. Compared with the prior art, the method has the advantage that the method is carried out in a single activation atmosphere (CO)2Or NH3) Or compared with the biomass carbon material prepared by pyrolysis in inert atmosphere, the nitrogen-doped porous biomass carbon prepared by the invention has higher surface area and more developed pore structure, and the stability and methanol resistance are obviously improved and improvedThe catalyst has more excellent electrocatalytic oxygen reduction performance in alkaline electrolyte, so the catalyst has very wide application prospect in the field of electrocatalytic materials of fuel cells.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a TEM image of nitrogen-doped porous biomass carbon provided in example 4 of the present invention;
FIG. 2 shows N of the products of examples 1 and 4 and comparative examples 1 to 42Adsorption and desorption curve graphs;
FIG. 3 is a BJH pore size distribution diagram of articles of examples 1 and 4 and comparative examples 1-4 provided by the invention;
FIG. 4 is a graph comparing the electrocatalytic oxygen reduction capacity of the articles of example 1 provided by the present invention with the articles of comparative examples 1-4;
FIG. 5 is a graph comparing the electrocatalytic oxygen reduction capacity of the articles of examples 1-5 provided by the present invention;
FIG. 6 is a graph comparing the electrocatalytic oxygen reduction capacity of articles of examples 4, 6, and 7 provided by the present invention;
FIG. 7 is a graph comparing the stability of articles of examples 1, 4 provided by the present invention with a commercial platinum carbon electrocatalyst;
figure 8 is a graph comparing the methanol resistance of the articles of examples 1 and 4 provided by the present invention with a commercial platinum carbon electrocatalyst.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a preparation method of nitrogen-doped porous biomass carbon, which comprises the following steps:
sequentially placing the biomass chitosan in inert gas atmosphere and CO2Atmosphere and NH3And carrying out pyrolysis in the atmosphere to obtain the nitrogen-doped porous biomass carbon.
In the preparation method provided by the invention, firstly, the biomass chitosan is pyrolyzed in an inert gas atmosphere. Wherein the relative molecular mass of the biomass chitosan is preferably 300000-1000000 Da, and specifically can be 300000Da, 350000Da, 400000Da, 450000Da, 500000Da, 550000Da, 594000Da, 600000Da, 650000Da, 700000Da, 750000Da, 800000Da, 850000Da, 900000Da, 950000Da or 1000000 Da; the particle size of the biomass chitosan is preferably more than 400 meshes; the deacetylation degree of the biomass chitosan is preferably 80-95%. In the present invention, the biomass chitosan is preferably dried and ball-milled before being pyrolyzed. The particle size of the biomass chitosan before ball milling is preferably 200-300 meshes; the drying temperature is preferably 70-90 ℃, and specifically can be 70 ℃, 75 ℃, 80 ℃, 85 ℃ or 90 ℃; the drying time is preferably 12-48 h, and specifically can be 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, 44h or 48 h; the diameter of the grinding body of the ball mill is preferably 2-4 mm, and specifically can be 2mm, 2.5mm, 3mm, 3.5mm or 4 mm; the rotation speed of the ball milling is preferably 400-600 revolutions/min, and specifically can be 400 revolutions/min, 450 revolutions/min, 500 revolutions/min, 550 revolutions/min or 600 revolutions/min; the ball milling time is preferably 10-20 h, and specifically can be 10h, 12h, 15h, 17h or 20 h.
In the preparation method provided by the invention, during the pyrolysis process in the inert gas atmosphere, the inert gas is preferably argon; the temperature rise starting temperature of the pyrolysis is room temperature, the temperature rise rate of the pyrolysis is 3-7 ℃/min, preferably 5-6 ℃/min, and more preferably 5 ℃/min; the temperature rise end point temperature of the pyrolysis is 400-600 ℃, preferably 500-550 ℃, and more preferably 500 ℃; the thermal insulation time of the pyrolysis is 1-3 h, preferably 2-2.5 h, and more preferably 2 h; the equipment used for pyrolysis is preferably a slow pyrolysis furnace.
In the preparation method provided by the invention, after the thermal insulation hydrolysis of the biomass chitosan in the inert gas atmosphere is finished, the hydrolysis is continued in CO2The pyrolysis is carried out in an atmosphere. Wherein in the CO2The temperature rise starting temperature for pyrolysis in the atmosphere is the heat preservation temperature for pyrolysis in the inert gas atmosphere (namely, the temperature rise end temperature for pyrolysis in the inert gas atmosphere), and the temperature rise rate for pyrolysis is 8-15 ℃/min, preferably 10-12 ℃/min, and more preferably 10 ℃/min; the temperature rise end point temperature of the pyrolysis is 700-800 ℃, and specifically can be 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃ or 800 ℃; the thermal insulation time of the pyrolysis is 1-8 h, and specifically can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8 h; the apparatus used for the pyrolysis preferably follows the slow pyrolysis furnace that is preferably used when the pyrolysis is carried out in an inert gas atmosphere.
In the preparation method provided by the invention, the biomass chitosan is in the CO2After the thermal decomposition in the atmosphere is finished, continuously adding NH3The pyrolysis is carried out in an atmosphere. Wherein in the NH3The temperature rise starting temperature for pyrolysis in the atmosphere is at the CO2The temperature for carrying out pyrolysis in the atmosphere is kept at a temperature, wherein the temperature rise rate of the pyrolysis is 8-15 ℃/min, preferably 10-12 ℃/min, and more preferably 10 ℃/min; the temperature rise end point of the pyrolysis is 700-900 ℃, specifically 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃, 800 ℃, 810 ℃, 820 ℃, 830 ℃, 840 ℃, 850 ℃, 860 ℃, 870 ℃, 880 ℃, 890 ℃ or 900 ℃; the thermal insulation time of the pyrolysis is 1-8 h, and specifically can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8 h. In the present invention, if at NH3Temperature of the end point of temperature rise for pyrolysis in the atmosphere and the CO2The heat preservation temperature for pyrolysis in the atmosphere is consistent, and the heat preservation pyrolysis is directly carried out without a temperature rise process. In the present invention, the equipment used for the pyrolysis is preferably used for CO2A slow pyrolysis furnace is preferably used when the pyrolysis is carried out in an atmosphere.
In the preparation method provided by the invention, the biomass chitosan is in NH3And after the thermal hydrolysis in the atmosphere is finished, obtaining the nitrogen-doped porous biomass carbon.
According to the preparation method provided by the invention, proper pyrolysis temperature and pyrolysis atmosphere are optimally designed, so that biomass chitosan is firstly pyrolyzed into biomass carbon coarse material in inert gas atmosphere; then passing through CO2The biomass carbon coarse material is etched by violent reaction with carbon, so that the biomass carbon coarse material generates a large amount of microporous structures, and the surface area of the biomass carbon coarse material is increased; thereafter using NH3And weak reaction with carbon is continuously carried out, so that the surface area and the pore structure of the biomass carbon coarse material are further improved, and nitrogen supplement is carried out on the biomass carbon coarse material. Compared with the prior art, the method has the advantage that the method is carried out in a single activation atmosphere (CO)2Or NH3) Or compared with a biomass carbon material prepared by pyrolysis in an inert atmosphere, the nitrogen-doped porous biomass carbon prepared by the method has higher surface area and more developed pore structure, the stability and methanol resistance are obviously improved, and the nitrogen-doped porous biomass carbon has more excellent electrocatalytic oxygen reduction performance in alkaline electrolyte, so that the nitrogen-doped porous biomass carbon has very wide application prospect in the field of electrocatalytic materials of fuel cells.
The invention also provides a catalyst ink comprising a catalyst and a membrane solution. Wherein, the catalyst comprises the nitrogen-doped porous biomass carbon prepared by the preparation method in the technical scheme; the membrane solution is preferably a Nafion membrane solution, and the concentration of the Nafion membrane solution is preferably 3-7 wt%, and specifically can be 3 wt%, 4 wt%, 5 wt%, 6 wt% or 7 wt%; the preferable dosage ratio of the catalyst to the membrane solution is (8-15) mg:100 μ L, specifically 8mg:100 μ L, 9mg:100 μ L, 10mg:100 μ L, 11mg:100 μ L, 12mg:100 μ L, 13mg:100 μ L, 14mg:100 μ L or 15mg:100 μ L. In the invention, the catalyst ink further comprises a diluent, wherein the diluent comprises water and/or ethanol, preferably comprises water and ethanol, and the volume ratio of the water to the ethanol is (0.5-2): 1, more preferably 1: 1; the dosage ratio of the diluent to the catalyst is preferably 2mL: (8 to 15) mg, specifically 2mL:8mg, 2mL:9mg, 2mL:10mg, 2mL:11mg, 2mL:12mg, 2mL:13mg, 2mL:14mg or 2mL:15 mg.
The nitrogen-doped porous biomass carbon prepared by the method is added into the catalyst ink provided by the invention, so that the catalyst ink also has excellent electro-catalytic oxygen reduction performance, stability and methanol resistance, and has wide application prospect in the field of fuel cell electro-catalytic materials.
The invention also provides a fuel cell, and the catalyst adopted by the fuel cell comprises the nitrogen-doped porous biomass carbon prepared by the preparation method in the technical scheme. The fuel cell provided by the invention adopts the nitrogen-doped porous biomass carbon prepared by the invention as a catalyst, so that the electrochemical performance of the fuel cell is very excellent.
For the sake of clarity, the following examples are given in detail.
In the following examples and comparative examples of the present invention, the biomass chitosan used was purchased from national pharmaceutical group chemical agents, ltd, and had a degree of deacetylation of 80 to 95% and a particle size of 200 to 300 mesh relative to a molecular mass of 594000 Da.
Example 1
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2The temperature of the atmosphere reaches 800 ℃ at the heating rate of 10 ℃/min and is kept for 2 h; finally converted into NH3Keeping the atmosphere at 800 ℃ for 2h to obtain the nitrogen-doped porous biomass carbon which is marked as N/C800-800Or N/C800-800(CO2-NH3)。
Example 2
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2Keeping the atmosphere at 700 ℃ at the heating rate of 10 ℃/min for 2 h; finally converted into NH3Keeping the atmosphere at 700 ℃ for 2h to obtain the nitrogen-doped porous biomass carbon which is marked as N/C700-700。
Example 3
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2Keeping the atmosphere at 700 ℃ at the heating rate of 10 ℃/min for 2 h; finally converted into NH3The temperature of the atmosphere reaches 800 ℃ at the heating rate of 10 ℃/min and is kept for 2h, and the nitrogen-doped porous biomass carbon can be obtained and is recorded as N/C700-800。
Example 4
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, firstly, heating to 500 ℃ at a heating rate of 5 ℃/min under inert atmosphere Ar, and keeping2 h; then, it is converted into CO2Keeping the atmosphere at 700 ℃ at the heating rate of 10 ℃/min for 2 h; finally converted into NH3The temperature of the atmosphere reaches 900 ℃ at the heating rate of 10 ℃/min and is kept for 2h, and the nitrogen-doped porous biomass carbon can be obtained and is recorded as N/C700-90Or N/C700-9004h or N/C700-900(CO2-NH3)。
The Transmission Electron Microscope (TEM) observation of the nitrogen-doped porous biomass carbon prepared by the present invention is shown in fig. 1, and fig. 1 is a TEM image of the nitrogen-doped porous biomass carbon provided in example 4 of the present invention.
Example 5
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2The temperature of the atmosphere reaches 800 ℃ at the heating rate of 10 ℃/min and is kept for 2 h; finally converted into NH3The temperature of the atmosphere reaches 900 ℃ at the heating rate of 10 ℃/min and is kept for 2h, and the nitrogen-doped porous biomass carbon can be obtained and is recorded as N/C800-900。
Example 6
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2Keeping the atmosphere at 700 ℃ at the heating rate of 10 ℃/min for 1 h; finally converted into NH3The atmosphere was at 10 deg.CThe temperature rise rate of/min reaches 900 ℃ and is kept for 1h, and then the nitrogen-doped porous biomass carbon can be obtained, which is marked as N/C700-900-2h。
Example 7
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2Keeping the atmosphere at 700 ℃ at the heating rate of 10 ℃/min for 4 h; finally converted into NH3The temperature of the atmosphere reaches 900 ℃ at the heating rate of 10 ℃/min and is kept for 4h, and the nitrogen-doped porous biomass carbon can be obtained, and is marked as N/C700-900-8h。
Comparative example 1
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; and then, keeping the temperature at 800 ℃ at a heating rate of 10 ℃/min for 2h to obtain the nitrogen-doped porous biomass carbon, which is recorded as N/C (Ar-Ar).
Comparative example 2
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into CO2The temperature of the atmosphere reaches 800 ℃ at the heating rate of 10 ℃/min and is kept for 2h, and the nitrogen-doped porous biomass carbon can be obtained and is marked as N/C (Ar-CO)2)。
Comparative example 3
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into NH3The temperature of the atmosphere reaches 800 ℃ at the heating rate of 10 ℃/min and is kept for 2h, and the nitrogen-doped porous biomass carbon can be obtained and is marked as N/C (Ar-NH)3)。
Comparative example 4
(1) Pretreatment: placing the biomass chitosan in an oven at 80 ℃ for 24h, and removing water in the biomass; in order to make the distribution of the biological chitosan particles more uniform, the dried biological chitosan particles are placed in a ball mill for ball milling for 15 hours, the milling bodies are agate balls with the diameter of 3mm and 50 balls, and the particle size of the biological chitosan after ball milling is larger than 400 meshes.
(2) Pyrolysis and carbonization: placing 5g of pretreated chitosan in a slow pyrolysis furnace, and firstly, keeping the chitosan at 500 ℃ for 2h at a heating rate of 5 ℃/min in an inert atmosphere Ar; then, it is converted into NH3The temperature of the atmosphere reaches 800 ℃ at the heating rate of 10 ℃/min and is kept for 2h, and finally the atmosphere is converted into CO2Keeping the atmosphere at 800 ℃ for 2h to obtain the nitrogen-doped porous biomass carbon which is marked as N/C (NH)3-CO2)。
Evaluation of Effect
1) Microstructure
Nitrogen-doped porous biomass prepared in examples 1 and 4 and comparative examples 1 to 4Carbon by N2And (5) characterizing an adsorption and desorption curve, and the result is shown in figures 2-3. Wherein, FIG. 2 is N of the products of examples 1 and 4 and comparative examples 1 to 4 provided by the present invention2Adsorption and desorption curve graphs; FIG. 3 is a BJH pore size distribution diagram of products of examples 1 and 4 and comparative examples 1-4 provided by the invention.
As can be seen from FIGS. 2 to 3, the N/C prepared in example 1800-800S ofBET＝792m2The content of mesopores is obviously improved by taking micropores as main components; N/C prepared in example 4700-900S ofBET＝982m2The content of mesopores is obviously improved by taking micropores as main components; s of N/C (Ar-Ar) prepared in comparative example 1BET＝224m2The/g is mainly micropore, and no mesopore is observed; N/C (Ar-CO) prepared in comparative example 22) S ofBET＝677m2The concentration of the mesoporous material is determined by the concentration of the mesoporous material; N/C (Ar-NH) prepared in comparative example 33) S ofBET＝456m2The concentration of the mesoporous material is determined by the concentration of the mesoporous material; s of N/C (Ar-Ar) prepared in comparative example 4BET＝718m2In terms of/g, the micropores are dominant, and the appearance of a small amount of mesopores is observed.
2) Electrochemical performance
2.1) preparation of test electrodes: adding 12mg of porous biomass carbon powder into 2mL of mixed solution (water: ethanol in a volume ratio of 1:1) for ultrasonic treatment for 30min, adding 100 mu L of Nafion membrane solution with a mass fraction of 5%, and continuing ultrasonic treatment for 30min to obtain the catalyst ink. 10 mul of catalyst ink was dropped onto the surface of platinum carbon electrode to prepare the working electrode.
2.2) carrying out electrocatalytic oxygen reduction performance test on the prepared porous biomass carbon, wherein the specific test process comprises the following steps: testing of working electrode at O by rotating disk electrode and electrochemical workstation2Electrocatalytic oxygen reduction performance at 1600rpm rotation in saturated 0.1M KOH electrolyte. The test results are shown in fig. 4, 5 and 6. Wherein, FIG. 4 is a graph comparing the electrocatalytic oxygen reduction capacity of the product of example 1 provided by the present invention with the products of comparative examples 1-4; FIG. 5 is a graph comparing the electrocatalytic oxygen reduction capacity of the articles of examples 1-5 provided by the present invention; FIG. 6 is a drawing of a product of examples 4, 6 and 7 according to the inventionGraph comparing electrocatalytic oxygen reduction capacity. The specific analysis content of the test results is as follows:
the half-wave potential and the limiting current density are main standards for evaluating the electro-catalytic oxygen reduction performance of the material. As shown in FIG. 4, the electrocatalytic redox energies of example 1 and comparative examples 1, 2, 3 and 4. N/C (Ar-Ar), N/C (Ar-NH)3)、N/C(CO2-Ar)、N/C(NH3-CO2) And N/C800-800(CO2-NH3) Half-wave potential E of1/20.544, 0.673, 0.833, 0.838 and 0.860Vvs RHE, respectively; the limiting current densities are-2.178, -2.790, -4.023, -4.009 and-4.579 mA/cm2. By CO2-NH3The electrochemical performance of the nitrogen-doped porous biomass carbon obtained by the combination is obviously improved. To further optimize the materials, the nitrogen-doped porous biomass carbons obtained in examples 1, 2, 3, 4 and 5 were further tested for electrocatalytic oxygen reduction performance to determine the effect of calcination temperature. The test results are shown in FIG. 5, N/C700-700, N/C700-800, N/C700-900, and N/C800-800 (N/C)800-800(CO2-NH3) Same material) and the half-wave potential of N/C800-900 is 0.597, 0.796, 0.884, 0.860, 0.870 and 0.861V vs RHE; the limiting current density is-2.401, -3.245, -4.813, -4.579, -4.620 and-5.020 mA/cm2. Finally, the effect of calcination time on the electrochemical performance of the material was investigated, as shown in FIG. 6, where CO is present2-NH3When the combined mixing time is 4 hours, the nitrogen is doped with the porous biomass carbon N/C700-9004h (and N/C)700-900Being the same material) is optimal.
2.3) N/C prepared in examples 1 and 4800-800And N/C700-900And carrying out stability and methanol resistance tests on the catalyst and a commercial platinum-carbon electrocatalyst, wherein the specific test process comprises the following steps: using i-t mode of operation with the working electrode at O2The saturated 0.1M KOH electrolyte was held at 900rpm rotation, where the methanol tolerance test was 10mL of methanol added after 200s of run. The test results are shown in fig. 7 and 8. Wherein, FIG. 7 is a graph comparing the stability of the articles of examples 1 and 4 provided by the present invention with a commercial platinum carbon electrocatalyst; FIG. 8 shows the products of examples 1 and 4 and commercial Pt-C materials according to the present inventionComparative plot of methanol resistance of electrocatalyst.
As can be seen from fig. 7 and 8, the stability and methanol resistance of the prepared nitrogen-doped porous biomass carbon of the present invention are far superior to those of commercial platinum carbon. Among them, the excellent electrocatalytic oxygen reduction performance of nitrogen-doped porous biomass carbon may be related to the developed pore structure thereof.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A preparation method of nitrogen-doped porous biomass carbon comprises the following steps:
sequentially placing the biomass chitosan in inert gas atmosphere and CO2Atmosphere and NH3Carrying out pyrolysis in the atmosphere to obtain nitrogen-doped porous biomass carbon;
wherein the heating rate of pyrolysis in the inert gas atmosphere is 3-7 ℃/min, the temperature of the heating end point is 400-600 ℃, and the heat preservation time is 1-3 h;
in the CO2The temperature rise rate of pyrolysis in the atmosphere is 8-15 ℃/min, the temperature rise end point temperature is 700-800 ℃, and the heat preservation time is 1-8 h;
in the NH3The temperature rise rate of pyrolysis in the atmosphere is 8-15 ℃/min, the temperature rise end point temperature is 700-900 ℃, and the heat preservation time is 1-8 h.
2. The method according to claim 1, wherein the temperature rise rate of the pyrolysis in the inert gas atmosphere is 5 to 6 ℃/min, the temperature rise end point temperature is 500 to 550 ℃, and the holding time is 2 to 2.5 hours.
3. The method of claim 1, wherein the CO is present in the reaction mixture2The temperature rise rate for pyrolysis in the atmosphere is 10-12 ℃/min.
4. The method of claim 1, wherein the NH is present3The temperature rise rate for pyrolysis in the atmosphere is 10-12 ℃/min.
5. The method according to claim 1, wherein the relative molecular mass of the biomass chitosan is 300000-1000000 Da.
6. The method of claim 1, wherein the biomass chitosan has a particle size of > 400 mesh.
7. The method of claim 1, wherein the biomass chitosan is dried and ball milled before being pyrolyzed.
8. The preparation method according to claim 7, wherein the drying temperature is 70-90 ℃; the drying time is 12-48 h;
the diameter of the grinding body of the ball mill is 2-4 mm; the rotating speed of the ball mill is 400-600 revolutions per minute; the ball milling time is 10-20 h.
9. A catalyst ink comprising a catalyst and a membrane solution, wherein the catalyst comprises the nitrogen-doped porous biomass carbon prepared by the preparation method of any one of claims 1 to 8.
10. A fuel cell, characterized in that the catalyst used by the fuel cell comprises the nitrogen-doped porous biomass carbon prepared by the preparation method of any one of claims 1 to 8.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104525110A (en) * | 2014-12-18 | 2015-04-22 | 华中科技大学 | Nitrogen-enriched active biomass coke and preparation method thereof |
| CN105932234A (en) * | 2016-05-05 | 2016-09-07 | 华东师范大学 | Doped porous carbon spheres used for negative electrode material of sodium ion battery and preparation method for doped porous carbon spheres |
| CN106660009A (en) * | 2014-08-23 | 2017-05-10 | 恩特格里斯公司 | Microporous carbon adsorbent from natural carbohydrates |
| CN106672963A (en) * | 2015-11-09 | 2017-05-17 | 中国石油化工股份有限公司 | Active carbon and preparation method thereof |
| CN106881138A (en) * | 2017-03-12 | 2017-06-23 | 西北师范大学 | A kind of preparation method of nitrogen-phosphor codoping multiporous biological matter C catalyst |
| CN108232369A (en) * | 2017-12-29 | 2018-06-29 | 华南理工大学 | A kind of integrated form flexible electrode of biomass derived and preparation method thereof |
| CN108579790A (en) * | 2018-05-25 | 2018-09-28 | 万华化学集团股份有限公司 | A kind of preparation method of porous C catalyst of N doping and preparation method thereof and β-isophorone |
| CN109790034A (en) * | 2016-09-26 | 2019-05-21 | 迪睿合株式会社 | Porous carbon material and its manufacturing method and synthetic reaction catalyst |
| CN110467182A (en) * | 2019-09-07 | 2019-11-19 | 北方民族大学 | A kind of multi-stage porous carbon sill and its preparation method and application based on reaction template |
-
2019
- 2019-11-28 CN CN201911187871.8A patent/CN110854395A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106660009A (en) * | 2014-08-23 | 2017-05-10 | 恩特格里斯公司 | Microporous carbon adsorbent from natural carbohydrates |
| CN104525110A (en) * | 2014-12-18 | 2015-04-22 | 华中科技大学 | Nitrogen-enriched active biomass coke and preparation method thereof |
| CN106672963A (en) * | 2015-11-09 | 2017-05-17 | 中国石油化工股份有限公司 | Active carbon and preparation method thereof |
| CN105932234A (en) * | 2016-05-05 | 2016-09-07 | 华东师范大学 | Doped porous carbon spheres used for negative electrode material of sodium ion battery and preparation method for doped porous carbon spheres |
| CN109790034A (en) * | 2016-09-26 | 2019-05-21 | 迪睿合株式会社 | Porous carbon material and its manufacturing method and synthetic reaction catalyst |
| CN106881138A (en) * | 2017-03-12 | 2017-06-23 | 西北师范大学 | A kind of preparation method of nitrogen-phosphor codoping multiporous biological matter C catalyst |
| CN108232369A (en) * | 2017-12-29 | 2018-06-29 | 华南理工大学 | A kind of integrated form flexible electrode of biomass derived and preparation method thereof |
| CN108579790A (en) * | 2018-05-25 | 2018-09-28 | 万华化学集团股份有限公司 | A kind of preparation method of porous C catalyst of N doping and preparation method thereof and β-isophorone |
| CN110467182A (en) * | 2019-09-07 | 2019-11-19 | 北方民族大学 | A kind of multi-stage porous carbon sill and its preparation method and application based on reaction template |
Non-Patent Citations (1)
| Title |
|---|
| CHENG BIN-HAI等: "Recent developments of post-modification of biochar for electrochemical energy storage", 《BIORESOURCE TECHNOLOGY》 * |
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