Carbon-based non-metal catalyst, preparation method thereof and application of carbon-based non-metal catalyst in fuel cell cathode

Abstract

The invention provides a carbon-based nonmetal catalyst, a preparation method thereof and application of the carbon-based nonmetal catalyst in a fuel cell cathode, and relates to the technical field of fuel cell catalysts. The preparation method provided by the invention comprises the following steps: mixing a molecular sieve, a carbon source, a nitrogen source and concentrated sulfuric acid in a liquid environment, and evaporating to dryness to obtain a composite precursor; calcining the composite precursor in nitrogen at the temperature of 600-900 DEG C, and etching in a sodium hydroxide solution at the temperature of 70-90 DEG C to obtain a composite intermediate; and calcining the composite intermediate in ammonia gas at 600-900 DEG C, and cooling to obtain the carbon-based nonmetal catalyst. By adopting the molecular sieve as the template agent and co-doping the nitrogen element and the sulfur element on the carbon material with the molecular sieve skeleton, the catalyst has high specific surface area and unique pore structure of the molecular sieve, can improve the catalytic activity, does not need to use noble metal materials, and reduces the manufacturing cost; and the risk that metal active sites are poisoned can also be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell catalysts, and in particular to a carbon-based non-metallic catalyst and a preparation method thereof and application in a fuel cell cathode. Background Art

[0002] Fuel cells are a very promising clean energy source with the advantage of high energy efficiency. However, they are limited by the slow action of the cathode oxygen reduction reaction. Currently, most of the catalysts on the market use precious metal Pt as cathode catalysts. Because of this, the large-scale application of fuel cells is limited. To solve this problem, researchers have shifted their attention to how to reduce or eliminate the use of precious metals. Carbon-based non-metallic catalysts are a type of catalyst that does not require the use of metals. The catalyst can be made more active through methods such as heteroatom doping and manufacturing defects.

[0003] Xia Baoyu et al. (Tian X, Zhao X, Su YQ, et al. Engineering bunched Pt-Ni alloy nanocages for efficient oxygen reduction in practical fuel cells SI.pdf[J]. Science, 2019, 366(6467): 850-856. DOI: 10.1126 / science.aaw7493.) reported a catalyst for the cathode of a fuel cell, which is a one-dimensional bundled platinum-nickel alloy nanocage with a platinum shell structure. The catalyst has high activity and reduces the amount of platinum, but it is still impossible to completely avoid the use of precious metals; Liang Shuang et al. (Liang, S, et al., Highly Stable Co Single Atom Confined in Hierarchical Carbon Molecular Sieveas Efficient Electrocatalysts in Metal–Air Batteries. Advanced Energy Materials, 2022.12(11)) doped non-precious metal Co into carbon molecular sieves. Thanks to the unique pores of carbon molecular sieves, the Co-doped carbon molecular sieves obtained higher oxygen reduction activity, but their limiting current density did not reach the level of platinum-based catalysts; Han-Ik Joh (Lee HR, Han S, Lee JY, et al. Effect of pre-annealing on chemical configuration and heteroatom doping of highly active carbon catalysts for the oxygen reduction reaction[J]. Journal of Industrial and Engineering Chemistry, 2023, 128: 542-549. DOI: 10.1016 / j.jiec.2023.08.019.) et al. reported a heteroatom-doped graphene oxide catalyst that can carry out oxygen reduction reactions without using metals, providing a new choice for fuel cell cathode catalysts.

[0004] Although the above catalysts have shown certain potential in the field of fuel cell cathode catalysts, they each have some shortcomings. Although platinum-nickel alloy nanocages reduce the amount of platinum used, they still cannot get rid of the dependence on precious metals and are costly; although Co-doped carbon molecular sieves improve oxygen reduction activity, their limiting current density has not yet reached the standard of platinum-based catalysts; and although heteroatom-doped graphene oxide provides a new direction for metal-free catalysts, the complexity of its preparation process and long-term stability still need further exploration and optimization. Therefore, in the research and development of fuel cell cathode catalysts, continuous exploration and innovation are still needed to seek more efficient, stable and cost-effective catalyst materials. Therefore, it is urgent to provide a solution to improve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a carbon-based non-metallic catalyst, a preparation method thereof and an application in a fuel cell cathode. By using a molecular sieve as a template, nitrogen and sulfur elements are co-doped on a carbon material having a molecular sieve skeleton. It not only has a high specific surface area and a unique pore structure of the molecular sieve, but also can improve the catalytic activity. There is no need to use precious metal materials, which reduces the manufacturing cost and can also avoid the risk of poisoning of metal active sites.

[0006] In a first aspect, the present invention provides a method for preparing a carbon-based non-metallic catalyst, comprising: mixing a molecular sieve, a carbon source, a nitrogen source and concentrated sulfuric acid in a liquid environment and then evaporating the mixture to obtain a composite precursor; calcining the composite precursor under nitrogen at 600°C-900°C, and then etching the composite precursor in a sodium hydroxide solution at 70°C-90°C to obtain a composite intermediate; calcining the composite intermediate under ammonia at 600°C-900°C and then cooling the composite intermediate to obtain a carbon-based non-metallic catalyst.

[0007] Optionally, when the molecular sieve, the carbon source, the nitrogen source and the concentrated sulfuric acid are mixed in a liquid environment, the molecular sieve, the carbon source and the nitrogen source are dispersed in the liquid environment in advance, and then the concentrated sulfuric acid is added for mixing.

[0008] Optionally, the molecular sieve comprises MCM-48.

[0009] Optionally, the carbon source includes one of sucrose, glucose, starch, and glucosamine hydrochloride.

[0010] Optionally, the nitrogen source includes one of urea and melamine.

[0011] Optionally, the mass ratio of the carbon source to the nitrogen source is 1:(0.1-2).

[0012] Optionally, the preparation method of the molecular sieve includes: mixing and dissolving hexadecyltrimethyl sodium bromide and sodium hydroxide to obtain a mixed solution; adding a silicon source to the mixed solution for hydrothermal reaction, and then separating, drying and calcining to obtain the molecular sieve.

[0013] Optionally, the silicon source includes one of silica sol and tetraethyl orthosilicate.

[0014] Optionally, the mass ratio of the silicon source to the hexadecyltrimethyl sodium bromide is 1:(0.2-0.8).

[0015] Optionally, the mass ratio of the silicon source to the sodium hydroxide is 1:(0.02-0.1).

[0016] Optionally, the pH of the mixed solution is 12.5-14.

[0017] Optionally, a silicon source is added into the mixed solution, and a hydrothermal reaction is carried out at 140° C.-160° C.

[0018] Optionally, a silicon source is added into the mixed solution for hydrothermal reaction for 20 h to 28 h.

[0019] Optionally, after separation and drying, the molecular sieve is calcined at 400°C-700°C.

[0020] Optionally, after separation and drying, the temperature is increased at a rate of 2°C / min-8°C / min and kept warm for calcination to obtain the molecular sieve.

[0021] Optionally, after the molecular sieve, the carbon source, the nitrogen source and the concentrated sulfuric acid are mixed in a liquid environment, they are kept warm at 90° C.-110° C. and 140° C.-160° C. independently for 5 h-8 h.

[0022] Optionally, under a nitrogen atmosphere, the composite precursor is heated to 600° C.-900° C. at a rate of 1° C. / min-10° C. / min.

[0023] Optionally, under an ammonia atmosphere, the composite intermediate is heated to 600° C.-900° C. at a rate of 1° C. / min-10° C. / min.

[0024] Optionally, the concentration of the sodium hydroxide solution is 1 mol / L-3 mol / L.

[0025] Optionally, etching is performed in the sodium hydroxide solution for 10 h to 14 h.

[0026] Optionally, the etching is performed in the sodium hydroxide solution and then dried.

[0027] In a second aspect, the present invention also provides a carbon-based non-metallic catalyst prepared by any of the above optional preparation methods.

[0028] In a third aspect, the present invention also provides a use of a carbon-based non-metallic catalyst prepared by any of the above optional preparation methods in a cathode of a fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A flowchart of a method for preparing a carbon-based non-metallic catalyst provided by the present invention;

[0030] Figure 2 This is a SEM characterization image of the carbon-based non-metallic catalyst prepared in Example 1 of the present invention at a magnification of 50K;

[0031] Figure 3 This is a TEM characterization image of the carbon-based non-metallic catalyst prepared in Example 1 of the present invention when the scale is 10 nm;

[0032] Figure 4 is an XRD characterization diagram of the carbon-based non-metallic catalyst prepared in Example 1 of the present invention;

[0033] Figure 5 The linear sweep voltammogram of the carbon-based non-metallic catalyst prepared in Example 1 of the present invention;

[0034] Figure 6 This is a comparison chart of the activities of the carbon-based non-metallic catalyst prepared in Example 1 of the present invention and the Pt / C catalyst after being poisoned by methanol. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with general skills in the field to which the present invention belongs.

[0036] See also Figure 1 The present invention provides a method for preparing a carbon-based non-metallic catalyst, comprising the following steps:

[0037] S1, mixing molecular sieve, carbon source, nitrogen source and concentrated sulfuric acid in a liquid environment and evaporating to dryness to obtain a composite precursor;

[0038] S2, calcining the composite precursor at 600° C.-900° C. under nitrogen, and etching in a sodium hydroxide solution at 70° C.-90° C. to obtain a composite intermediate;

[0039] S3. The composite intermediate is calcined at 600° C.-900° C. under ammonia gas and then cooled to obtain a carbon-based non-metallic catalyst.

[0040] In fact, in step S1, the molecular sieve can be used as a template, a carbon layer can be covered on its surface, and nitrogen and sulfur elements can be introduced, so as to form a carbon-based skeleton material with a molecular sieve structure. In addition, by using concentrated sulfuric acid, not only sulfur elements can be introduced, but also the dehydration of concentrated sulfuric acid can be used to promote the covering and forming of carbon source and nitrogen source on the surface of the molecular sieve.

[0041] In fact, calcination in a high-temperature nitrogen atmosphere in step S2 is helpful to form a composite carbon skeleton on the surface of the molecular sieve. At the same time, the nitrogen atmosphere can not only protect the carbon, but also further dope the nitrogen element. After calcination and forming, etching in a sodium hydroxide solution can remove the molecular sieve template used, so that the composite carbon skeleton has a pore structure similar to that of the molecular sieve.

[0042] In fact, calcination under a nitrogen atmosphere in step S3 can further improve the bonding quality of nitrogen elements, sulfur elements and the carbon skeleton in the composite carbon skeleton. In addition, a secondary nitrogen doping treatment can be performed, and a graphene oxide layer can be formed at the edge of the catalyst skeleton, thereby presenting a structure in which graphene oxide and graphite coexist, and a state in which defects and pores coexist. This is beneficial for the catalyst to expose more active sites and enhance the uniformity of the distribution of active sites, and can significantly enhance the catalytic stability and anti-toxicity.

[0043] In some embodiments, when performing step S1 to mix the molecular sieve, the carbon source, the nitrogen source and the concentrated sulfuric acid in a liquid environment, the molecular sieve, the carbon source and the nitrogen source are dispersed in the liquid environment in advance, and then the concentrated sulfuric acid is added for mixing. In fact, by pre-mixing the molecular sieve, the carbon source and the nitrogen source, it is beneficial to improve the dispersion uniformity of the molecular sieve, the carbon source and the nitrogen source, and then after adding the concentrated sulfuric acid, it is beneficial to use the concentrated sulfuric acid to pre-carbonize the dehydration of the carbon source and the nitrogen source, so that the carbon material and the nitrogen element are covered and doped on the surface of the molecular sieve.

[0044] In a further embodiment, the molecular sieve used includes MCM-48. In fact, MCM-48 molecular sieve has a high specific surface area and a unique pore structure. The carbon-based non-metallic catalyst prepared by using MCM-48 molecular sieve as a template can inherit the pore structure of MCM-48, thereby improving the uniformity and number of active sites on the catalyst surface, which is conducive to improving the catalytic activity.

[0045] Specifically, the preparation method of MCM-48 molecular sieve includes: mixing and dissolving hexadecyl trimethyl sodium bromide and sodium hydroxide to obtain a mixed solution; adding a silicon source to the mixed solution for hydrothermal reaction, separating, drying, and roasting to obtain a molecular sieve. In fact, MCM-48 molecular sieve can also be synthesized using commercial products or other conventional methods in the laboratory.

[0046] In fact, when preparing MCM-48 molecular sieve, the silicon source used includes one of silica sol and ethyl orthosilicate, and the mass ratio of silicon source, hexadecyltrimethyl sodium bromide and sodium hydroxide in the mixed solution is 1: (0.2-0.8): (0.2-0.8). In addition, the pH of the prepared mixed solution is 12.5-14.

[0047] In some embodiments, when preparing MCM-48 molecular sieve, hexadecyltrimethyl sodium bromide and sodium hydroxide are mixed and dissolved in deionized water to prepare a mixed solution, and the amount of deionized water required is sufficient to completely dissolve hexadecyltrimethyl sodium bromide and sodium hydroxide.

[0048] In fact, when preparing MCM-48 molecular sieve, the silicon source is added to the mixed solution and hydrothermally reacted at 140°C-160°C for 20h-28h, then separated and dried and calcined at 400°C-700°C to obtain MCM-48 molecular sieve. Specifically, the silicon source and the mixed solution can be hydrothermally reacted in a high-pressure reactor, and after separation and drying, the temperature can be raised to 400°C-700°C at a rate of 2°C / min-8°C / min in a muffle furnace in an air atmosphere and calcined at a constant temperature.

[0049] In fact, the carbon source and nitrogen source used in step S1 can be organic reagents commonly used in the art, which must contain sufficient nitrogen and carbon elements. In addition, in order to reduce the preparation cost, the carbon source is preferably one of sucrose, glucose, starch, and glucosamine hydrochloride, and the nitrogen source is preferably one of urea and melamine.

[0050] In some embodiments, in step S1, the mass ratio of the carbon source to the nitrogen source is 1:(0.1-2). In fact, by adjusting the amount of the nitrogen source, the amount of nitrogen doping on the prepared carbon-based non-metallic catalyst can be adjusted, so that the catalytic activity of the catalyst can be dynamically regulated.

[0051] In fact, when the molecular sieve, the carbon source, the nitrogen source and the concentrated sulfuric acid are mixed in a liquid environment in step S1, the liquid environment used can be deionized water. In addition, after mixing, they are kept warm at 90°C-110°C and 140°C-160°C for 5h-8h independently of each other, which is conducive to the concentrated sulfuric acid to uniformly pre-carbonize the carbon source and the nitrogen source and form a uniform carbonization precursor on the surface of the molecular sieve.

[0052] In some embodiments, when performing step S2, the composite precursor is heated to 600°C-900°C at a rate of 1°C / min-10°C / min in a nitrogen atmosphere. Specifically, the composite precursor can be transferred to the furnace of a tube furnace in advance, and the tube furnace is gas-displaced with nitrogen, and then the tube furnace is uniformly heated, and the calcined product is cooled to room temperature and etched in a sodium hydroxide solution with a concentration of 1mol / L-3mol / L and 70°C-90°C, so that the molecular sieve template in the product can be removed and dried to obtain a pure composite intermediate.

[0053] In some embodiments, when performing step S3, the composite intermediate is heated to 600°C-900°C at a rate of 1°C / min-10°C / min in an ammonia atmosphere.

[0054] The present invention also provides a carbon-based non-metallic catalyst prepared by the preparation method in any of the above embodiments, comprising a carbon skeleton and doped nitrogen and sulfur elements, wherein the doped nitrogen element has a mass fraction of 2%-8% and the doped sulfur element has a mass fraction of 0.5%-2%. In addition, the carbon skeleton has a molecular sieve morphology.

[0055] Example 1

[0056] This embodiment 1 provides a method for preparing a carbon-based non-metallic catalyst, comprising the following steps:

[0057] S0, 9.85g of hexadecyltrimethylammonium bromide and 1.78g of sodium hydroxide were stirred and dissolved in 120mL of deionized water to prepare a mixed solution; 20g of tetraethyl orthosilicate was added to the mixed solution and stirred for 3h, then reacted in a hydrothermal reactor at 150°C for 24h, taken out, filtered and rinsed with deionized water until the washing liquid was neutral, dried in an oven at 80°C to constant weight, and then transferred to a muffle furnace, the muffle furnace was heated to 650°C at a rate of 5°C / min and calcined for 3h, and cooled to room temperature with the furnace to obtain MCM-48 molecular sieve;

[0058] S1. Add 2g MCM-48 molecular sieve, 1g glucosamine hydrochloride and 1.5g urea into 10mL deionized water and stir to mix, then add 2mL 98% concentrated sulfuric acid and stir to mix for pre-carbonization, keep in an oven at 100°C for 6h, then keep in an oven at 150°C for 6h, and cool to room temperature to obtain a composite precursor;

[0059] S2. Grind and crush the composite precursor and place it in the furnace of a tube furnace. In a nitrogen atmosphere, heat the tube furnace to 900°C at a rate of 5°C / min and keep it warm for 2 hours, then cool it to room temperature with the furnace, add 100mL of 2mol / L sodium hydroxide solution to the resulting product, etch it in an 80°C water bath for 12 hours, separate it by suction, and dry it in an 80°C oven to constant weight to obtain a composite intermediate;

[0060] S3. The composite intermediate is placed in the furnace of a tubular furnace. In an ammonia atmosphere, the tubular furnace is heated to 900°C at a rate of 5°C / min and kept warm for 2 hours. After cooling to room temperature, the composite intermediate is ground to obtain a carbon-based non-metallic catalyst.

[0061] Example 2

[0062] This embodiment 2 provides a method for preparing a carbon-based non-metallic catalyst, which is different from embodiment 1 in that in step S0, 11.46 g of hexadecyltrimethylammonium bromide and 2.13 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucosamine hydrochloride, and 1 g of urea are added to 10 mL of deionized water.

[0063] Example 3

[0064] This Example 3 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 32.45 g of hexadecyltrimethylammonium bromide and 6.21 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water.

[0065] Example 4

[0066] This Example 4 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 7.63 g of hexadecyltrimethylammonium bromide and 1.78 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and calcined in a muffle furnace at 650° C. for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucosamine hydrochloride, and 1.5 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 900° C. for 3 h.

[0067] Example 5

[0068] This Example 5 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 6.99 g of hexadecyltrimethylammonium bromide and 2.13 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucose, and 1.5 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 900° C. for 3 h.

[0069] Example 6

[0070] This Example 6 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 10.54 g of hexadecyltrimethylammonium bromide and 1.56 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of sucrose, and 1.5 g of urea are added to 10 mL of deionized water.

[0071] Example 7

[0072] This Example 7 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 11.89 g of hexadecyltrimethylammonium bromide and 2.01 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and calcined in a muffle furnace at 650° C. for 2 h, and in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of starch, and 1.5 g of urea are added to 10 mL of deionized water.

[0073] Example 8

[0074] This Example 8 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 8.34 g of hexadecyltrimethylammonium bromide and 1.92 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and calcined in a muffle furnace at 600° C. for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucosamine hydrochloride, and 1.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 850° C. for 2 h.

[0075] Example 9

[0076] This Example 9 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 12.02 g of hexadecyltrimethylammonium bromide and 1.67 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is raised to 600°C in a muffle furnace at a rate of 3°C / min and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucose, and 1.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 850°C for 2 h.

[0077] Example 10

[0078] This embodiment 10 provides a method for preparing a carbon-based non-metallic catalyst, which is different from embodiment 1 in that in step S0, 7.21 g of hexadecyltrimethylammonium bromide and 2.25 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is increased to 600°C at a rate of 3°C / min in a muffle furnace and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of sucrose, and 1.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 850°C for 2 h.

[0079] Embodiment 11

[0080] This Example 11 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 9.15 g of hexadecyltrimethylammonium bromide and 1.54 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is raised to 600°C in a muffle furnace at a rate of 3°C / min and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of starch, and 1.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 850°C for 2 h.

[0081] Example 12

[0082] This Example 12 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 10.12 g of hexadecyltrimethylammonium bromide and 2.30 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is raised to 600°C in a muffle furnace at a rate of 5°C / min and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucosamine hydrochloride, and 1 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 800°C for 3 h.

[0083] Embodiment 13

[0084] This Example 13 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 12.27 g of hexadecyltrimethylammonium bromide and 1.89 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is raised to 600°C in a muffle furnace at a rate of 5°C / min and calcined for 3 hours, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucose, and 1 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 800°C for 3 hours.

[0085] Embodiment 14

[0086] This Example 14 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 8.87 g of hexadecyltrimethylammonium bromide and 2.07 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is raised to 550°C at a rate of 5°C / min in a muffle furnace and calcined for 3 hours; in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of sucrose, and 1 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 800°C for 2 hours.

[0087] Embodiment 15

[0088] This Example 15 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 7.58 g of hexadecyltrimethylammonium bromide and 1.71 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is raised to 550°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of starch, and 1 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 800°C for 2 h.

[0089] Example 16

[0090] This Example 16 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 9.43 g of hexadecyltrimethylammonium bromide and 1.62 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the mixture is heated to 550°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h. In step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucosamine hydrochloride, and 1.0 g of melamine are added to 10 mL of deionized water, and the mixture is kept warm in a muffle furnace at 750°C for 2 h in steps S2 and S3.

[0091] Embodiment 17

[0092] This Example 17 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 11.23 g of hexadecyltrimethylammonium bromide and 2.21 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the mixture is heated to 550°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h. In step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucose, and 1.0 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 750°C for 2 h.

[0093] Embodiment 18

[0094] This Example 18 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 7.98 g of hexadecyltrimethylammonium bromide and 1.97 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is increased to 550°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h; in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of sucrose, and 1.0 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 750°C for 2 h.

[0095] Embodiment 19

[0096] This Example 19 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 8.56 g of hexadecyltrimethylammonium bromide and 1.59 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is increased to 700°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h; in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucosamine hydrochloride, and 1.0 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 750°C for 2 h.

[0097] Embodiment 20

[0098] This Example 20 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 35.67 g of hexadecyltrimethylammonium bromide and 5.33 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is increased to 700°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of glucose, and 0.5 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 650°C for 2 h.

[0099] Embodiment 21

[0100] This Example 21 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 29.89 g of hexadecyltrimethylammonium bromide and 7.41 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is increased to 700°C at a rate of 5°C / min in a muffle furnace and calcined for 2 h, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of sucrose, and 0.5 g of urea are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 650°C for 2 h.

[0101] Embodiment 22

[0102] This Example 22 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 24.87 g of hexadecyltrimethylammonium bromide and 7.09 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is increased to 700°C at a rate of 3°C / min in a muffle furnace and calcined for 3 hours; in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of starch, and 0.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 650°C for 2 hours.

[0103] Embodiment 23

[0104] This Example 23 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 31.23 g of hexadecyltrimethylammonium bromide and 6.17 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water, and the temperature is increased to 700°C at a rate of 3°C / min in a muffle furnace and calcined for 3 h; in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of sucrose, and 0.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 650°C for 2 h.

[0105] Embodiment 24

[0106] This Example 24 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that in step S0, 27.34 g of hexadecyltrimethylammonium bromide and 7.58 g of sodium hydroxide are stirred and dissolved in 120 mL of deionized water to prepare a mixed solution, and then 20 g of nano-silicon dioxide is added to the mixed solution, and the temperature is increased to 700°C at a rate of 3°C / min in a muffle furnace and calcined for 3 hours, in step S1, 2 g of MCM-48 molecular sieve, 1.5 g of starch, and 0.5 g of melamine are added to 10 mL of deionized water, and in steps S2 and S3, the mixture is kept warm in a muffle furnace at 650°C for 2 hours.

[0107] Comparative Example 1

[0108] This comparative example 1 provides a method for preparing a carbon-based non-metallic catalyst, which is different from Example 1 in that, in step S3, the tubular furnace is heated to 900° C. at a rate of 5° C. / min under an argon atmosphere and kept warm for 2 hours.

[0109] Comparative Example 2

[0110] This comparative example 2 provides a method for preparing a carbon-based non-metallic catalyst, which is different from that of Example 1 in that 2 mL of 98% concentrated sulfuric acid is not added for pre-carbonization in step S1.

[0111] Comparative Example 3

[0112] This comparative example 3 provides a method for preparing a carbon-based non-metallic catalyst, which is different from that of example 1 in that no MCM-48 molecular sieve is added in step S1.

[0113] Performance Testing

[0114] The catalytic performance of the carbon-based non-metallic catalysts prepared in Examples 1 to 24 and Comparative Examples 1 to 3 was evaluated, including: taking 2.5 mg of the carbon-based non-metallic catalyst, 250 μL of deionized water, 750 μL of anhydrous ethanol solution and 50 μL of Nafion solution (perfluororesin solution) to prepare an Ink solution, and using a pipette to transfer 32 μL of the Ink solution to a rotating ring disk electrode, using 0.1 mol / L potassium hydroxide solution as an electrolyte, and detecting the limiting current density at a rotation speed of 1600 rpm, a scanning frequency of 10 mV / s, and a scanning range of 0-1.1 V relative to the hydrogen electrode. The results are shown in Table 1.

[0115] The carbon-based non-metallic catalyst prepared in Example 1 was observed using a scanning electron microscope at a magnification of 50K, and its SEM image is as follows: Figure 2 The carbon-based non-metallic catalyst prepared in Example 1 was observed using a transmission electron microscope at a scale of 10 nm, and its TEM image is as shown Figure 3 As shown; the carbon-based non-metallic catalyst prepared in Example 1 was characterized by XRD as shown Figure 4 The carbon-based non-metal catalyst prepared in Example 1 was subjected to a linear voltammetric sweep test as shown in Figure 5 As shown; the carbon-based non-metallic catalyst prepared in Example 1 and the Pt / C catalyst (purchased from Suzhou Shengernuo Technology Co., Ltd., model SPT20X) were tested for activity after methanol poisoning, as shown Figure 6 shown.

[0116] Table 1 Limiting current density results

[0117]

[0118]

[0119] from Figure 2 and Figure 3 It can be seen that the carbon-based non-metallic catalyst prepared in Example 1 has a graphite-like structure, and a spirally curved pore wall structure of MCM-48 molecular sieve can be observed, which indicates that the synthesized carbon-based non-metallic catalyst has a molecular sieve structure. Figure 4 It can be seen that the 002 and 001 planes of graphite can be observed at 24.7° and 43.7°, respectively, and a broad diffraction peak similar to graphene oxide appears at 10.9°. Figure 5 It can be seen that the limiting current density of the carbon-based non-metallic catalyst prepared in Example 1 is -6.2 mA / cm 2 , half-wave potential is 0.77V, and starting potential is 0.91V. Figure 6 It can be seen that the carbon-based non-metallic catalyst prepared in Example 1 has excellent resistance to methanol toxicity.

[0120] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A method for preparing a carbon-based non-metallic catalyst, characterized in that: include: A molecular sieve, a carbon source, a nitrogen source and concentrated sulfuric acid are mixed in a liquid environment and evaporated to obtain a composite precursor; the composite precursor is calcined at 600°C-900°C in nitrogen and then etched in a sodium hydroxide solution at 70°C-90°C to obtain a composite intermediate; the composite intermediate is calcined at 600°C-900°C in ammonia and then cooled to obtain a carbon-based non-metallic catalyst.

2. The preparation method according to claim 1, characterized in that: When the molecular sieve, the carbon source, the nitrogen source and the concentrated sulfuric acid are mixed in a liquid environment, the molecular sieve, the carbon source and the nitrogen source are dispersed in the liquid environment in advance, and then the concentrated sulfuric acid is added for mixing; wherein: the molecular sieve comprises MCM-48; and / or the carbon source comprises one of sucrose, glucose, starch, and glucosamine hydrochloride; and / or the nitrogen source comprises one of urea and melamine; and / or the mass ratio of the carbon source to the nitrogen source is 1:(0.1-2).

3. The preparation method according to claim 1 or 2, characterized in that: The preparation method of the molecular sieve comprises: mixing and dissolving hexadecyltrimethyl sodium bromide and sodium hydroxide to obtain a mixed solution; adding a silicon source into the mixed solution for hydrothermal reaction, and then separating, drying and roasting to obtain the molecular sieve.

4. The preparation method according to claim 3, characterized in that: The silicon source includes one of silica sol and tetraethyl orthosilicate; and / or, the mass ratio of the silicon source to the hexadecyltrimethyl sodium bromide is 1:(0.2-0.8); and / or, the mass ratio of the silicon source to the sodium hydroxide is 1:(0.02-0.1); and / or, the pH of the mixed solution is 12.5-14.

5. The preparation method according to claim 3, characterized in that: Add the silicon source into the mixed solution and carry out a hydrothermal reaction at 140°C-160°C; and / or, add the silicon source into the mixed solution and carry out a hydrothermal reaction for 20h-28h; and / or, after separation and drying, calcine at 400°C-700°C to obtain the molecular sieve; and / or, after separation and drying, heat at a rate of 2°C / min-8°C / min and keep warm and calcine to obtain the molecular sieve.

6. The preparation method according to claim 1, characterized in that: After the molecular sieve, carbon source, nitrogen source and concentrated sulfuric acid are mixed in a liquid environment, they are kept warm at 90° C.-110° C. and 140° C.-160° C. independently for 5 h-8 h.

7. The preparation method according to claim 1, characterized in that: In a nitrogen atmosphere, the composite precursor is heated to 600°C-900°C at a rate of 1°C / min-10°C / min; and / or, in an ammonia atmosphere, the composite intermediate is heated to 600°C-900°C at a rate of 1°C / min-10°C / min.

8. The preparation method according to claim 1, characterized in that: When etching in a sodium hydroxide solution at 70° C.-90° C., the method includes: the concentration of the sodium hydroxide solution is 1 mol / L-3 mol / L; and / or, etching in the sodium hydroxide solution for 10 h-14 h; and / or, drying after etching in the sodium hydroxide solution.

9. A carbon-based non-metallic catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of a carbon-based non-metallic catalyst prepared by the preparation method according to any one of claims 1 to 8 in a cathode of a fuel cell.

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