A porous carbon electrode material of a bio-based monopyrrole precursor and a preparation method and application thereof

Abstract

The application discloses a kind of porous carbon electrode materials of bio-based monopyrrole precursor and its preparation method and application, first step is to a certain proportion of aldehyde and pyrrole under acidic conditions, filter washes and dries, and carbon material precursor A is obtained;Second step is to the carbon material precursor A prepared with a certain proportion of activating agent under nitrogen atmosphere high-temperature activation, sufficient washing, freeze-drying, and the porous carbon electrode material of bio-based monopyrrole precursor is obtained.The porous carbon electrode material of bio-based monopyrrole precursor prepared by the application has high specific surface area, good conductivity, stable physical and chemical properties, stronger gas-liquid permeability and adjustable pore structure, and is expected to be applied in lithium battery, adsorbent, catalyst carrier, wastewater treatment agent and the like.

Description

Technical Field

[0001] This invention belongs to the field of bio-based porous carbon materials, specifically relating to a porous carbon electrode material based on a bio-based monoporphyrin precursor, its preparation method, and its application. Background Technology

[0002] The choice of negative electrode material directly affects the energy density of a battery. Among the diverse range of negative electrode materials, porous carbon materials constitute a large proportion, including graphite, graphene, carbon nanotubes, activated carbon, and carbon fibers. However, most of these carbon materials are high-value-added products of fossil fuels, and they have some drawbacks in actual production, including high cost, complex structure, and cumbersome preparation, which hinders the large-scale production of advanced battery materials.

[0003] Biomass and its derivatives possess advantages such as low cost, large reserves, and green sustainability, and are widely used as precursors for the production of carbon materials. In particular, through the design of bio-based precursors, bio-based porous carbon materials can possess high specific surface area, good electrical conductivity, stable physicochemical properties, strong gas-liquid permeability, and tunable pore structure. These characteristics make them promising for applications in energy storage and conversion, catalysts, and adsorption separation.

[0004] As a negative electrode material in batteries, bio-based porous carbon materials can accommodate more ions and provide higher capacity due to their high specific surface area; their complex multidimensional porous structure provides effective diffusion channels and shorter diffusion distances; therefore, they are widely used in ion batteries and supercapacitors, and have better electrochemical performance than traditional graphite carbon.

[0005] The main structure of porphyrin molecules consists of four pyrroles linked by methylene groups. They are a class of compounds with large molecular weights, highly conjugated systems, and significant biological representativeness. A porphyrin monomer refers to a porphyrin molecule containing only one porphyrin host, exhibiting excellent chemical and thermal stability. Furfural and 5-hydroxymethylfurfural are highly attractive biomass platform compounds, derived from the hydrolysis products of hemicellulose and cellulose, respectively. Vanillin is an organic compound extracted from vanilla beans (a member of the Rutaceae family) and is widely used in the food, beverage, cosmetic, daily chemical, and pharmaceutical industries. Cinnamaldehyde is a yellow, viscous liquid, abundant in plants such as cinnamon. Naturally occurring cinnamaldehyde is always in the trans configuration; the molecule consists of an acrolein atom linked to a phenyl group, thus it can be considered an acrolein derivative. This invention uses any one of furfural, vanillin, cinnamaldehyde, and 5-hydroxymethylfurfural as raw materials to react with pyrrole to prepare a bio-based monoporphyrin precursor, and uses it as a raw material to prepare porous carbon materials. This invention has certain theoretical guidance and application significance for promoting the advancement of biomass battery anode materials. Summary of the Invention

[0006] Technical problem solved: This invention provides a porous carbon electrode material with a bio-based monoporphyrin precursor, its preparation method and application. The precursor with a monoporphyrin structure is prepared from bio-based raw materials, and then activated at high temperature with potassium hydroxide or sodium hydroxide to produce a porous carbon material with rich pores. The abundant pores provide effective ion diffusion channels, and its high specific surface area allows for more ion binding sites, thereby improving capacity.

[0007] Technical Solution: A method for preparing porous carbon electrode material based on bio-based monoporphyrin precursors: Step 1: Mix aldehydes and pyrroles in a molar ratio of 1:(1-1.1), then disperse the resulting mixture in an acidic liquid, reflux under nitrogen protection for 8-14 hours, cool to room temperature, filter, wash and dry to obtain carbon material precursor A; Step 2: In a nitrogen atmosphere, react carbon material precursor A with an activator at a mass ratio of (1-3):1, activate at 700-900℃ for 3-5 hours, wash and dry to obtain porous carbon electrode material based on bio-based monoporphyrin precursors.

[0008] Preferably, the aldehydes mentioned above are any one of furfural, vanillin, cinnamaldehyde, and 5-hydroxymethylfurfural.

[0009] Preferably, the pH of the acidic liquid is ≤5.

[0010] Preferably, the acidic liquid is propionic acid or hydrochloric acid.

[0011] Preferably, the activator is potassium hydroxide or sodium hydroxide.

[0012] Preferably, the mass ratio of the carbon material precursor A to the activator is 1:2.

[0013] Preferably, the reaction temperature of the above-mentioned activation stage is 800°C.

[0014] The above preparation method yields a porous carbon electrode material based on a bio-based monoporphyrin precursor.

[0015] Application of the above materials in electrode preparation.

[0016] Beneficial effects: (1) The bio-based monoporphyrin precursor in this invention exhibits a smooth spherical morphology under scanning electron microscopy, with electron-donating porphyrin groups containing large π bonds as structural units, rich in active sites, possessing abundant pore structure and good stability. Using this as a precursor, porous carbon materials with nanoscale mesopores are prepared, exhibiting high specific surface area. (2) The preparation process of this invention is simple, the reaction is controllable, and the obtained product has stable properties and certain utilization value. (3) The porous carbon electrode material with the bio-based monoporphyrin precursor exhibits high capacity retention and cycling stability under high current density. This research has a good promoting significance for the high-value-added utilization of bio-based materials. Attached Figure Description

[0017] Figure 1 The infrared spectra of furfural, pyrrole, and precursor A in Examples 1-4 are shown.

[0018] In the infrared spectrum of furfural, 1667 cm⁻¹ -1 The characteristic absorption peak of the aldehyde group appears. Comparison of the infrared spectra of furfural, pyrrole, and precursor A shows that the characteristic absorption peak of the aldehyde group in the original furfural structure (1667 cm⁻¹) is present. -1 The value disappears at 1547 cm⁻¹ in the infrared spectrum of bio-based porphyrin precursor A. -1 and 1460cm -1 Characteristic vibrational peaks of C=C and CH on the porphyrin macrocycle appeared at 3110 cm⁻¹. -1 A broad peak appeared at the location, indicating unsaturated CH vibrations on the porphyrin macrocycle.

[0019] Figure 2 The NMR spectrum of the bio-based monoporphyrin carbon source shows that the three peaks at 110.2, 129.4 and 151.3 ppm correspond to the porphyrin macrocycle, while the peak at 171.7 ppm is attributed to the carbon of the conjugated ring that was bridged after the reaction.

[0020] Figure 3 SEM image of carbon material precursor A, the first step product.

[0021] Figure 4 This is an SEM image of the porous carbon electrode material, the product of the second step.

[0022] Figure 5 The capacity retention rate is the result of 4000 cycles under a high-density current of 10A / g.

[0023] Figure 6 The coulombic efficiency stability was determined under a high-density current of 10 A / g for 10,000 cycles. Detailed Implementation

[0024] All parts not described herein are the same as or can be implemented using existing technologies. The following are preferred embodiments of the present invention, but the present invention is not limited to the following limited embodiments, and any slight modifications to the embodiments shall also be considered within the scope of protection of the present invention.

[0025] Example 1

[0026] Step 1: Add furfural (60 mmol) and pyrrole (60 mmol) to 1200 mL of propionic acid at a 1:1 molar ratio. Reflux at 140 °C for 8 h under a nitrogen atmosphere. Cool to room temperature, filter, wash, and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react carbon material precursor A obtained in the previous step with potassium hydroxide at a mass ratio of 2:1. Activate at 700 °C for 5 h, wash, and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0027] Example 2

[0028] Step 1: Add furfural (60 mmol) and pyrrole (60 mmol) to 1200 mL of hydrochloric acid (pH 3-4) at a 1:1 molar ratio. Reflux at 140 °C for 10 h under a nitrogen atmosphere. Cool to room temperature, filter, wash, and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react carbon material precursor A obtained in the previous step with sodium hydroxide at a mass ratio of 2:1. Activate at 800 °C for 4 h, wash, and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0029] Example 3

[0030] Step 1: Add furfural (60 mmol) and pyrrole (66 mmol) to 1200 mL of propionic acid at a molar ratio of 1:1.1. Recycle at 140 °C for 14 h under a nitrogen atmosphere. Cool to room temperature, filter, wash and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react carbon material precursor A obtained in the previous step with potassium hydroxide at a mass ratio of 2:1. Activate at 900 °C for 3 h, wash and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0031] Example 4

[0032] Step 1: Add furfural (60 mmol) and pyrrole (60 mmol) to 1200 mL of propionic acid at a 1:1 molar ratio. Reflux at 140 °C for 10 h under a nitrogen atmosphere. Cool to room temperature, filter, wash, and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react the carbon material precursor A obtained in the previous step with potassium hydroxide at a mass ratio of 2:1. Activate at 800 °C for 4 h, wash, and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0033] The yield data of precursor A in the first step and porous carbon material in the second step of Examples 1-4 are shown in the table below:

[0034] Table 1. Step-by-step yield data

[0035] Example 1 81.20％ 44.26％ Example 2 89.35％ 52.60％ Example 3 90.81％ 56.50％ Example 4 89.63％ 60.06％

[0036] Analysis of specific surface area, pore volume, pore size and electrochemical performance of porous carbon materials

[0037] Based on the yield of each embodiment, Example 4, which has the highest yield of porous carbon, was selected for adsorption performance testing.

[0038] The specific surface area and pore volume of carbon materials are key performance indicators of porous carbon anode materials. Test results show that the porous carbon prepared by this method has excellent performance and a larger specific surface area than that of porous carbon prepared by direct carbonization of biomass such as coconut shells, making it suitable for anode material applications in water-based batteries.

[0039] The carbon material obtained in Example 4 exhibits the following test results regarding its charge-discharge cycle stability under high current density: Figure 5 and Figure 6 , Figure 5 The results show that the battery anode made of porous carbon electrode material still retains 88.47% of its charge specific capacity after 4000 cycles under a high-density current of 10 A / g. Figure 6 This indicates that under a high-density current of 10 A / g, the coulombic efficiency remains within a small range close to 100% after 10,000 cycles.

[0040] Table 2. Specific surface area, pore volume, and pore size analysis data of porous carbon materials in Example 4.

[0041]

[0042] Example 5

[0043] Step 1: Add furfural (60 mmol) and pyrrole (60 mmol) to 1000 mL of hydrochloric acid (pH 1-2) at a 1:1 molar ratio. Reflux at 140 °C for 10 h under a nitrogen atmosphere. Cool to room temperature, filter, wash, and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react the carbon material precursor A obtained in the previous step with potassium hydroxide at a mass ratio of 2:1. Activate at 800 °C for 4 h, wash, and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0044] Example 6

[0045] Step 1: Vanillin (60 mmol) and pyrrole (60 mmol) were added to 1200 mL of hydrochloric acid (pH 4-5) at a 1:1 molar ratio. The mixture was refluxed at 140 °C for 10 h under a nitrogen atmosphere. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, the carbon material precursor A obtained in the previous step was reacted with potassium hydroxide at a mass ratio of 2:1. The mixture was activated at 800 °C for 4 h, washed, and dried to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0046] Example 7

[0047] Step 1: Cinnamaldehyde (60 mmol) and pyrrole (60 mmol) were added to 1200 mL of propionic acid at a 1:1 molar ratio. The mixture was refluxed at 140 °C for 10 h under a nitrogen atmosphere. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, carbon material precursor A obtained in the previous step was reacted with potassium hydroxide at a mass ratio of 2:1. The mixture was activated at 800 °C for 4 h, washed, and dried to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

[0048] Example 8

[0049] Step 1: Add 60 mmol of 5-hydroxymethylfurfural and 60 mmol of pyrrole to 1200 mL of propionic acid at a 1:1 molar ratio. Reflux at 140 °C for 10 h under a nitrogen atmosphere. Cool to room temperature, filter, wash, and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react the carbon material precursor A obtained in the previous step with potassium hydroxide at a mass ratio of 2:1. Activate at 800 °C for 4 h, wash, and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

Claims

1. A method for preparing porous carbon electrode materials based on bio-based monoporphyrin precursors, characterized in that, Step 1: Add 60 mmol of furfural and 60 mmol of pyrrole to 1200 mL of propionic acid at a 1:1 molar ratio. Reflux at 140 °C for 10 h under a nitrogen atmosphere. Cool to room temperature, filter, wash, and dry to obtain carbon material precursor A. Step 2: Under a N2 atmosphere, react the carbon material precursor A obtained in the previous step with potassium hydroxide at a mass ratio of 2:

1. Activate at 800 °C for 4 h, wash, and dry to obtain a porous carbon electrode material with a bio-based monoporphyrin precursor.

2. The porous carbon electrode material of the bio-based monoporphyrin precursor prepared by the preparation method of claim 1.

3. The use of the material described in claim 2 in the preparation of electrodes.

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