Three-dimensional bio-based hierarchical pore nanocarbon water photovoltaic power generation material and preparation method and application thereof

Abstract

The invention discloses a three-dimensional bio-based hierarchical pore nanocarbon water photovoltaic power generation material as well as a preparation method and application of the three-dimensional bio-based hierarchical pore nanocarbon water photovoltaic power generation material. The specific technical scheme of the preparation method comprises the following steps: firstly, preparing an acetic acid solution containing chitosan, glucose and borax, and standing the solution at room temperature for 24 hours; then, freeze-drying the precursor solution, and pre-carbonizing xerogel in a drying oven for a certain time; and finally, adding a certain amount of water into the pre-carbonized dry gel, putting the pre-carbonized dry gel into a reaction kettle with a polytetrafluoroethylene lining, reacting for a certain time at a certain temperature, dialyzing the obtained wet gel, and drying at normal temperature and normal pressure to prepare the nano carbon aerogel with the hierarchical pore structure. The nano carbon aerogel has good hydrophilicity, abundant surface charges and a hierarchical pore structure, and is a low-cost and excellent water evaporation induced power generation material.

Description

Technical Field

[0001] This invention belongs to the field of novel power generation technology, and specifically discloses a three-dimensional bio-based hierarchical porous nanocarbon water photovoltaic power generation material, its preparation method and application. Background Technology

[0002] By 2025, the global population will exceed 8 billion. Rapid population growth and rapid industrialization have exacerbated electricity consumption, leading to severe power shortages. Evaporation-induced power generation (EEG) is a green power generation technology developed in recent years. This technology utilizes the interaction between water and material surfaces to induce electricity, offering a significant opportunity to address the power shortage. Existing EEG materials mainly include carbon-based materials (such as carbon black, graphene, and carbon nanotubes), metal-based materials (such as metal-organic frameworks, MXene, hydrotalcite, zeolite, and alumina), and biomass-based materials (such as wood, cellulose, and chitosan). Among these, carbon-based materials show promising application prospects in EEG due to their abundant sources, tunable surface properties, and excellent stability. EEG is based on the double-layer theory; therefore, the surface properties of the material (such as surface functional groups, wettability, and zeta potential) and pore structure (micron- and nano-scale channels) are crucial factors affecting its EEG performance. In existing research, the most common carbon-based materials are carbon black, carbon nanotubes, and graphene. Most studies focus on controlling the surface structure of carbon-based materials to enhance their water evaporation-induced power generation performance, with very little research on the water evaporation-induced power generation performance of carbon aerogels. This is because carbon aerogels typically originate from the carbonization of precursors in an inert atmosphere. This high-temperature carbonization results in poor hydrophilicity, low surface functional group density, and difficulty in controlling the pore structure, further hindering their suitability as water evaporation-induced power generation materials. Summary of the Invention

[0003] The purpose of this invention is to provide a three-dimensional bio-based hierarchical porous nanocarbon water photovoltaic power generation material, its preparation method and application, to endow carbon aerogel with water evaporation-induced power generation performance, and to use it as a water photovoltaic power generation device to generate electricity to alleviate power shortage.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a three-dimensional bio-based hierarchical porous nanocarbon-water photovoltaic material includes the following steps: S1: Chitosan, mono / disaccharide and boron-based crosslinking agent are dissolved sequentially in 0.2 mol / L acetic acid solution, and the solution is allowed to stand at room temperature for 24 h; S2: Freeze-dry the precursor solution prepared in S1 to obtain a dry gel, and pre-carbonize the dry gel in an oven for a certain time. S3: Add a certain amount of water to the pre-carbonized dry gel and place it in a reaction vessel with a polytetrafluoroethylene liner. React at a certain temperature for a certain time. Dialyze the obtained wet gel and dry it at room temperature and pressure to prepare a nano-carbon aerogel with a hierarchical porous structure.

[0005] Further, in step S1, the chitosan is α, β, or γ type chitosan with a deacetylation degree ≥75%, the monosaccharide is glucose or fructose, the disaccharide is sucrose or lactose, and the boron-based crosslinking agent includes inorganic boron compounds such as borax and organic boron crosslinking agents such as borate esters and phenylboronic acid; the concentrations of chitosan, monosaccharides, disaccharides, and crosslinking agents are 5~20 g / L, 60~300 g / L, and 2.5~7.5 g / L, respectively.

[0006] Furthermore, in step S2, the freezing method is direct freezing, freeze-thaw cycle freezing, or unidirectional freezing, the freeze-drying time is 24~72 h, and the pre-carbonization temperature is 60~120℃ for 2~6 h.

[0007] Furthermore, in step S3, the hydrothermal reaction temperature is 180 ℃~240 ℃, and the reaction time is 4 h~12 h.

[0008] A three-dimensional bio-based hierarchical porous nanocarbon aerogel prepared by any of the above preparation methods.

[0009] An application of a bio-based hierarchical porous carbon nanogel, as described above, as a material for water evaporation-induced power generation.

[0010] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The bio-based hierarchical porous carbon nanogel prepared by this invention has water evaporation-induced power generation performance, which proves the feasibility of bio-based carbon aerogel as a water evaporation-induced power generation material. It can be used as a water photovoltaic power generation device to generate electricity and alleviate the power shortage.

[0011] 1. Compared with other water evaporation-induced power generation materials, the main raw materials selected in this invention are derived from waste biomass or biomass derivatives, which have advantages such as low cost, wide availability, renewability and environmental friendliness.

[0012] 2. The bio-based hierarchical porous carbon nanogel prepared by this invention is assembled from carbon nanoparticles and has a hierarchical pore structure of macropore-mesopore-micropore, high content of surface functional groups, good hydrophilicity and excellent mechanical properties.

[0013] 3. The bio-based hierarchical porous carbon nanogel prepared by this invention has good power generation performance, with a maximum voltage of 0.35V and a maximum current of 700 nA. Attached Figure Description

[0014] Figure 1 SEM image of CSCA-1 in Example 1 Figure 2 The images shown are (a) an optical photograph, (b) an FTIR image, and (c) a Raman image of CSCA-1 in Example 1. Figure 3 The open-circuit voltage of CSCA-1 in Example 1 is (a) in NaCl solutions of different concentrations and (b) in deionized water. Detailed Implementation

[0015] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto. It should be noted that those skilled in the art can easily understand the structural design principle of the present invention, and those skilled in the art can make any modifications or alterations to the present invention, but other instances obtained without creative effort are all within the scope of protection of the present invention.

[0016] This invention discloses a three-dimensional bio-based hierarchical porous carbon nanotube aerogel, its preparation method, and its application. Using chitosan, mono / disaccharides, and boron-based crosslinking agents as the main raw materials, a hierarchical porous carbon nanotube aerogel composed of carbon nanoparticles with good hydrophilicity, high functional group density, and tunable pore structure is prepared by freeze-drying-hydrothermal method, which gives it good water evaporation-induced power generation performance.

[0017] Example 1 Step 1: Add a certain amount of chitosan to 18 mL of 0.2 mol / L acetic acid solution to make its concentration 10 g / L. After it is fully dissolved, add 2.25 g of glucose to make its concentration 110 g / L. After it is completely dissolved, add 2 mL of 50 g / L borax solution and sonicate to make it completely dissolved. Let the resulting mixed solution stand at room temperature for 24 h. Step 2: Freeze-dry the precursor solution prepared in Step 1, and pre-carbonize the resulting dry gel in an oven at 80°C for 4 h. Step 3: Add a certain amount of water to the pre-carbonized dry gel to make the dry gel saturated with water, and place the obtained wet gel in a reaction vessel with a polytetrafluoroethylene liner. React at 200℃ for 10 h. Dialyze the obtained wet gel in ethanol for 3 days, wash it with distilled water, and dry it at room temperature and pressure. Name the prepared hierarchical porous nanocarbon aerogel CSCA-1.

[0018] Example 2 Step 1: Add a certain amount of chitosan to 18 mL of 0.2 mol / L acetic acid solution to make its concentration 10 g / L. After it is fully dissolved, add 2.25 g of glucose to make its concentration 110 g / L. After it is completely dissolved, add 2 mL of 25 g / L borax solution and sonicate to make it completely dissolved. Let the resulting mixed solution stand at room temperature for 24 h. Step 2: Freeze-dry the precursor solution prepared in Step 1, and pre-carbonize the resulting dry gel in an oven at 80°C for 4 h. Step 3: Add a certain amount of water to the pre-carbonized dry gel to make the dry gel saturated with water, and place the obtained wet gel in a reaction vessel with a polytetrafluoroethylene liner. React at 200℃ for 10 h. Dialyze the obtained wet gel in ethanol for 3 days, wash it with distilled water, and dry it at room temperature and pressure. Name the prepared hierarchical porous nanocarbon aerogel CSCA-2.

[0019] Example 3 Step 1: Add a certain amount of chitosan to 18 mL of 0.2 mol / L acetic acid solution to make its concentration 10 g / L. After it is fully dissolved, add 2.25 g of glucose to make its concentration 110 g / L. After it is completely dissolved, add 2 mL of 50 g / L borax solution and sonicate to make it completely dissolved. Let the resulting mixed solution stand at room temperature for 24 h. Step 2: Freeze-dry the precursor solution prepared in Step 1, and pre-carbonize the resulting dry gel in an oven at 80°C for 4 h. Step 3: Add a certain amount of water to the pre-carbonized dry gel to make the dry gel saturated with water, and place the obtained wet gel in a reaction vessel with a polytetrafluoroethylene liner. React at 200℃ for 4 h. Dialyze the obtained wet gel in ethanol for 3 days, wash it with distilled water, and dry it at room temperature and pressure. Name the prepared hierarchical porous nanocarbon aerogel CSCA-3.

[0020] Example 4 Step 1: Add a certain amount of chitosan to 18 mL of 0.2 mol / L acetic acid solution to make its concentration 10 g / L. After it is fully dissolved, add 2.25 g of glucose to make its concentration 110 g / L. After it is completely dissolved, add 2 mL of 50 g / L 1,4-phenylenediboric acid solution and sonicate to make it completely dissolved. Let the resulting mixed solution stand at room temperature for 24 h. Step 2: Freeze-dry the precursor solution prepared in Step 1, and pre-carbonize the resulting dry gel in an oven at 80°C for 4 h. Step 3: Add a certain amount of water to the pre-carbonized dry gel to make the dry gel saturated with water, and place the obtained wet gel in a reaction vessel with a polytetrafluoroethylene liner. React at 200℃ for 12 h. Dialyze the obtained wet gel in ethanol for 3 days, wash it with distilled water, and dry it at room temperature and pressure. Name the prepared hierarchical porous nanocarbon aerogel CSCA-4.

[0021] Example 5 Step 1: Add a certain amount of chitosan to 18 mL of 0.2 mol / L acetic acid solution to make its concentration 10 g / L. After it is fully dissolved, add 2.25 g of sucrose to make its concentration 110 g / L. After it is completely dissolved, add 2 mL of 25 g / L borax solution and sonicate to make it completely dissolved. Let the resulting mixed solution stand at room temperature for 24 h. Step 2: Freeze-dry the precursor solution prepared in Step 1, and pre-carbonize the resulting dry gel in an oven at 80°C for 4 h. Step 3: Add a certain amount of water to the pre-carbonized dry gel to make the dry gel saturated with water, and place the obtained wet gel in a reaction vessel with a polytetrafluoroethylene liner. React at 200℃ for 10 h. Dialyze the obtained wet gel in ethanol for 3 days, wash it with distilled water, and dry it at room temperature and pressure. Name the prepared hierarchical porous nanocarbon aerogel CSCA-5. Figure 1 The image shows a SEM image of CSCA-1 in Example 1. The surface of the CSCA-1 sample has a macroporous structure with a size of about 30~50 μm. It can also be seen that the carbon aerogel is assembled from carbon nanoparticles with a size of 50~100 nm. These nanoparticles stack together to form mesoporous and microporous structures.

[0023] Figure 2 For example, (a) an optical photograph, (b) an FTIR image, and (c) a Raman image of CSCA-1 in Example 1, from... Figure 2 As can be seen from (a), the CSCA sample can withstand a weight exceeding 200 times its own mass. Figure 2 As can be seen in (b), the surface of CACA-1 contains oxygen-containing functional groups such as C=O and COC, as well as C=C functional groups, indicating that the precursor underwent an aromatization reaction during the hydrothermal process. From Figure 2 (c) It can be seen that the ID / IG value of the CSCA-1 sample is 0.65, indicating that the degree of graphitization of the sample prepared by hydrothermal carbonization is low.

[0024] Figure 3For example 1, the open-circuit voltage of CSCA-1 (a) in NaCl solutions of different concentrations and the open-circuit current in deionized water are calculated. Figure 3 As shown in (a), the CSCA-1 sample possesses water evaporation power generation performance. The open-circuit voltage of the fabricated device in deionized water is stable at 353 mV, and the open-circuit current is stable at 6.5 μA. Figure 3 (b) As the NaCl concentration increases, the water evaporation-induced power generation performance improves. When the NaCl concentration is 7wt%, the open circuit voltage is the highest (430mV), which is 20% higher than that in deionized water.

Claims

1. A method for preparing a three-dimensional bio-based hierarchical porous nanocarbon-water photovoltaic material, characterized in that, Includes the following steps: S1: Chitosan, mono / disaccharide and boron-based crosslinking agent are dissolved sequentially in 0.2 mol / L acetic acid solution, and the solution is allowed to stand at room temperature for 24 h; S2: Freeze-dry the precursor solution prepared in S1 to obtain a dry gel, and pre-carbonize the dry gel in an oven for a certain time. S3: Add a certain amount of water to the pre-carbonized dry gel and place it in a reaction vessel with a polytetrafluoroethylene liner. React at a certain temperature for a certain time. Dialyze the obtained wet gel and dry it at room temperature and pressure to prepare a nano-carbon aerogel with a hierarchical porous structure.

2. The method for preparing three-dimensional bio-based hierarchical porous nanocarbon-water photovoltaic materials according to claim 1, characterized in that, In step S1, the chitosan is α, β, or γ type chitosan with a deacetylation degree ≥75%. The monosaccharide is glucose or fructose, and the disaccharide is sucrose or lactose. The boron-based crosslinking agent includes inorganic boron compounds such as borax and organic boron crosslinking agents such as borate esters and phenylboronic acid. The concentrations of chitosan, monosaccharides, disaccharides, and crosslinking agents are 5~20 g / L, 60~300 g / L, and 2.5~7.5 g / L, respectively.

3. The method for preparing three-dimensional bio-based hierarchical porous nanocarbon-water photovoltaic materials according to claim 2, characterized in that, In step S2, the freezing method is direct freezing, freeze-thaw cycle freezing, or unidirectional freezing, the freeze-drying time is 24~72 h, and the pre-carbonization temperature is 60~120℃ for 2~6 h.

4. The preparation method of the three-dimensional bio-based hierarchical porous nanocarbon-water photovoltaic material according to claim 3, characterized in that, In step S3, the hydrothermal reaction temperature is 180 ℃~240 ℃, and the reaction time is 4 h~12 h.

5. A three-dimensional bio-based hierarchical porous nanocarbon aerogel prepared by any one of the preparation methods described in claims 1-4.

6. The application of the bio-based hierarchical porous nanocarbon aerogel as described in claim 5 as a material for water evaporation-induced power generation.

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