Biomass carbon-based composite catalyst and preparation method and application thereof
By preparing a biomass carbon-based Fe-MOF-5 catalyst, the problem of water generation as a side reaction in the two-electron oxygen reduction reaction of existing electrode materials was solved, the yield and selectivity of hydrogen peroxide were improved, and sustainable green synthesis and environmental remediation were realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2023-05-05
- Publication Date
- 2026-06-19
AI Technical Summary
Existing electrode materials generate water as a side reaction in the two-electron oxygen reduction reaction, which reduces the yield of hydrogen peroxide, is costly, and has limited sources, making it difficult to achieve sustainable large-scale synthesis.
Based on biomass materials, a biomass-based carbon-based Fe-MOF-5 catalyst was prepared through a composite Zn-Fe bimetallic MOF catalyst and a simple carbonization process. This catalyst increases oxygen-containing functional groups and electrocatalytic active sites, and is used for electrochemical two-electron oxygen reduction reactions.
It improves the production efficiency and selectivity of hydrogen peroxide, has good economic and environmental benefits, and is suitable for sustainable green synthesis of hydrogen peroxide and environmental remediation.
Smart Images
Figure CN116497396B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new electrocatalytic materials technology, and more specifically, to a novel biomass carbon-based composite catalyst, its preparation method, and its application. Background Technology
[0002] Hydrogen peroxide, as an environmentally friendly strong oxidant, is one of the most important chemicals of the 21st century. Its reaction products are only water and oxygen. Hydrogen peroxide can also serve as an ideal energy carrier for petroleum or hydrogen because it can be used to generate electricity in fuel cells. It is widely used in the chemical industry and energy and environmental fields.
[0003] The electrochemical synthesis of hydrogen peroxide using the two-electron oxygen reduction (OR) technique involves an electrolytic cell and electrodes. Oxygen or dissolved oxygen adsorbed on the cathode surface gains electrons, triggering a redox reaction that synthesizes hydrogen peroxide in situ. The two-electron OR method can be performed under ambient temperature and pressure, and uses only oxygen as the initial feedstock, making the process more environmentally friendly and safer. Currently, electrode materials for the two-electron OR reaction to synthesize hydrogen peroxide mainly include noble metals and carbon-based materials. However, the two-electron OR process is accompanied by a four-electron OR side reaction that generates water, reducing the yield of hydrogen peroxide. Furthermore, these electrode materials are expensive and have limited availability, hindering the sustainable large-scale synthesis of hydrogen peroxide. Biochar (BCs), derived from biomass, is widely available and inexpensive. Using waste biomass as a carbon-based material to prepare cathode catalysts for in-situ electrochemical synthesis of hydrogen peroxide offers significant economic and environmental benefits and has great potential as a replacement for the aforementioned non-renewable carbon-based materials. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for preparing a biomass carbon-based composite catalyst. The prepared biomass carbon-based composite catalyst has excellent catalytic performance and is beneficial to promoting the production of hydrogen peroxide.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] A method for preparing a biomass carbon-based composite catalyst includes the following steps:
[0007] S1. Pre-treatment of natural biomass materials: Pre-impregnating the pre-treated biomass materials;
[0008] S2. The biomass material is immersed in a mixed solution, and the biomass material and the mixed solution undergo a hydrothermal reaction. The biomass material is then washed and vacuum dried to obtain the biomass-based material.
[0009] S3. Carbonize the biomass-based material to obtain a biomass-carbon-based composite catalyst.
[0010] Preferably, the natural biomass material is at least one of poplar, pine, paulownia, fir, oak, birch, eucalyptus, straw, bamboo, sugarcane bagasse, and reed.
[0011] Preferably, the pretreatment method for natural biomass materials is as follows: the natural biomass materials are cut perpendicular to the growth direction, ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities, and then air-dried to obtain pretreated biomass materials.
[0012] Preferably, the mixed solution comprises an iron-containing compound, a zinc-containing compound, an organic acid, and an organic solvent, and the method for preparing the mixed solution is as follows:
[0013] The organic acid is dissolved in an organic solvent to form a first solution;
[0014] Iron-containing organic compounds and zinc-containing organic compounds are dissolved in an organic solvent to form a second solution;
[0015] The second solution is mixed with the first solution to form a mixed solution.
[0016] Preferably, the mass-to-volume ratio of organic acid to organic solvent in the mixed solution is 1~2:20~100 g / mL.
[0017] Preferably, the molar ratio of iron ions, zinc ions and organic acids in the mixed solution is 1:2~50:2~10.
[0018] Preferably, the iron-containing compound is at least one of dicyclopentadiene iron, ferric citrate, ferric acetylacetone, ferric glycine, ferric chloride, ferric nitrate, and ferric acetate; the zinc-containing compound is at least one of zinc carbonate, zinc sulfide, zinc sulfate, and zinc nitrate; the organic acid is at least one of isophthalic acid, terephthalic acid, benzoic acid, oxalic acid, formic acid, oxalic acid, and acetic acid; and the organic solvent is at least one of acetone, methanol, ethanol, cyclochloropropane, sulfolane, N,N-dimethylformamide, butyl acetate, methylpyrrolidone, propyl propionate, and dichloromethane.
[0019] Preferably, in step S1, the pre-impregnation time is 12~72 h;
[0020] In step S2, the impregnation temperature is 100℃~150℃ and the impregnation time is 12~72 h; the hydrothermal reaction temperature is 90℃~150℃ and the hydrothermal reaction time is 12~72 h; the vacuum drying temperature is 80℃~130℃.
[0021] In step S3, the carbonization temperature is 700~1500℃ and the carbonization time is 2~10 h.
[0022] A biomass carbon-based composite catalyst is prepared by any of the above-described methods for preparing biomass carbon-based composite catalysts.
[0023] Preferably, the biomass carbon-based composite catalyst is used as the cathode catalyst layer in the electrochemical two-electron oxygen reduction reaction to produce hydrogen peroxide.
[0024] Compared with existing technologies, this invention selects natural biomass materials as carbon precursor materials for the electrochemical two-electron oxygen reduction reaction to produce hydrogen peroxide. Biomass carbon-based cathode material, biomass-based Fe-MOF-5, is prepared through a composite Zn-Fe bimetallic MOF catalyst and a simple carbonization process. By introducing Fe-MOF-5, the oxygen-containing functional groups of the biomass carbon, the active sites of the electrocatalytic reaction, and the two-electron oxygen reduction selectivity are increased, which is beneficial to promoting the production of hydrogen peroxide and has great application prospects in the sustainable green synthesis of hydrogen peroxide and environmental remediation. Attached Figure Description
[0025] Figure 1 This is a flowchart of a method for preparing a biomass carbon-based composite catalyst.
[0026] Figure 2 This is a schematic diagram of a method for preparing biomass carbon-based composite catalysts.
[0027] Figure 3 This is a scanning electron microscope image of biomass-based Fe-MOF-5.
[0028] Figure 4 Scanning electron microscope image of biomass carbon-based Fe-MOF-5.
[0029] Figure 5 This is a comparison of the electrochemical performance of the biomass carbon-based Fe-MOF-5 composite catalyst with other catalysts.
[0030] Figure 6 This is a comparison chart of hydrogen peroxide production between the biomass carbon-based Fe-MOF-5 composite catalyst and other catalysts. Detailed Implementation
[0031] The biomass carbon-based composite catalyst of the present invention, its preparation method, and its application will be further described below with reference to the accompanying drawings and specific embodiments.
[0032] Please see Figure 1 and Figure 2 This invention discloses a method for preparing a biomass carbon-based composite catalyst, which includes the following steps:
[0033] S1. Pre-treatment of natural biomass materials: Pre-impregnating the pre-treated biomass materials;
[0034] S2. The biomass material is immersed in a mixed solution, and the biomass material and the mixed solution undergo a hydrothermal reaction. The biomass material is then washed and vacuum dried to obtain the biomass-based material.
[0035] S3. Carbonize the biomass-based material to obtain a biomass-carbon-based composite catalyst.
[0036] This invention prepares biomass-based Fe-MOF-5 material by pre-treating natural biomass materials, pre-impregnating the pre-treated biomass materials, immersing the biomass materials in a mixed solution under high-temperature conditions for an extended period, and then subjecting the biomass materials and the mixed solution to a hydrothermal reaction under high-temperature conditions. The biomass materials are then repeatedly washed with organic solvents and vacuum dried to obtain the final biomass-based Fe-MOF-5 composite catalyst. The biomass-based Fe-MOF-5 material is then carbonized under high-temperature conditions.
[0037] Specifically, in step S1, the natural biomass material is at least one of poplar, pine, paulownia, fir, oak, birch, eucalyptus, straw, bamboo, sugarcane bagasse, and reed.
[0038] The pretreatment method for natural biomass materials is as follows: the natural biomass materials are cut perpendicular to the growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities, and then air-dried to obtain pretreated biomass materials. In this invention, ultrasonic cleaning with anhydrous ethanol not only unblocks the pores of the biomass materials, but also allows the energy generated by the ultrasound to partially damage the cell walls of the fibers, which is beneficial for subsequent catalyst composites.
[0039] In step S2, an organic acid is first dissolved in an organic solvent to form a first solution. Then, an iron-containing organic compound and a zinc-containing organic compound are dissolved in the organic solvent to form a second solution. The second solution is then mixed with the first solution to form a mixed solution. The pretreated biomass material is pre-impregnated in the first solution, and then impregnated for an extended period in the mixed solution under high temperature conditions. The biomass material is then repeatedly washed with an organic solvent and vacuum dried. There are various methods for forming the mixed solution; in this invention, it is preferred to use an iron-containing compound, a zinc-containing compound, and an organic acid dissolved in an organic solvent to form the mixed solution.
[0040] The iron-containing compound is at least one of dicyclopentadiene iron, ferric citrate, ferric acetylacetone, ferric glycine, ferric chloride, ferric nitrate, and ferric acetate; the zinc-containing compound is at least one of zinc carbonate, zinc sulfide, zinc sulfate, and zinc nitrate; the organic acid is at least one of isophthalic acid, terephthalic acid, benzoic acid, oxalic acid, formic acid, and acetic acid; and the organic solvent is one of acetone, methanol, ethanol, cyclochloropropane, sulfolane, N,N-dimethylformamide, butyl acetate, methylpyrrolidone, propyl propionate, and dichloromethane.
[0041] This invention involves vacuum drying natural biomass materials after multiple impregnations and washes. After pre-impregnation in a first solution for 12-72 hours, the biomass materials are impregnated in a mixed solution at 100℃-150℃ for 12-72 hours. Then, the biomass materials and the mixed solution undergo a hydrothermal reaction at 90℃-150℃ for 12-72 hours. After multiple washes, the biomass materials are vacuum dried at 80℃-130℃ to prepare biomass-based Fe-MOF-5 materials. Scanning electron microscopy images of the biomass-based Fe-MOF-5 are shown below. Figure 3 As shown.
[0042] This invention utilizes the abundant carboxyl groups provided by organic acids, which enhance the hydrophilicity of the material and combine with the hydroxyl groups present in the biomass material, enabling Fe-MOF-5 to grow better in situ within the cell lumen of the biomass material. Furthermore, after a hydrothermal reaction, terephthalic acid coordinates with metal ions Zn and Fe, forming an in-situ structure of alternating coordination of Zn, Fe, and terephthalic acid within the pores of the wood block.
[0043] The mass-to-volume ratio of organic acid to organic solvent in the mixed solution is 1~2:20~100 g / mL, and the molar ratio of iron ions, zinc ions and organic acid in the mixed solution is 1:2~50:2~10.
[0044] In step S3, the treated biomass-based Fe-MOF-5 material is carbonized at a high temperature of 700~1500℃ for 2~10 h to finally obtain a biomass carbon-based Fe-MOF-5 composite catalyst. The scanning electron microscope image of the biomass carbon-based Fe-MOF-5 is shown below. Figure 4 As shown.
[0045] The preparation method of the biomass carbon-based composite catalyst of the present invention is to prepare biomass carbon-based cathode material through a simple one-step carbonization process. The preparation method is simple. By introducing Fe-MOF-5, the oxygen-containing functional groups of carbon in biomass material, the active sites of electrocatalytic reaction and the two-electron oxygen reduction selectivity are increased, which is conducive to promoting the production of hydrogen peroxide. It has great application prospects in sustainable green synthesis of hydrogen peroxide and environmental remediation.
[0046] Example 1
[0047] Natural poplar wood was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural poplar biomass material. 1.0 g of benzoic acid was dissolved in 35 ml of N,N-dimethylformamide solution, and then the natural poplar biomass material was added until submerged, and impregnated under vacuum for 72 h.
[0048] Add 2.97 g zinc sulfate, 0.70 g acetylacetone iron, and 35 ml N,N-dimethylformamide solution and stir to mix. Then, vacuum impregnate at 100 °C for 24 h. After that, place the biomass material and the mixed solution into a high-pressure reactor and hydrothermally react at 110 °C for 36 h. After natural cooling, take out the biomass material and place it in 35 ml N,N-dimethylformamide solution for ultrasonic cleaning for 30 min, then ultrasonic cleaning with 50 ml dichloromethane for 30 min, then soak in dichloromethane for 24 h, and then vacuum dry at 80 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0049] The biomass-based Fe-MOF-5 material obtained above was heated to 1200 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 5 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0050] Example 2
[0051] Natural pine wood was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural pine biomass material. 2.0 g of isophthalic acid was dissolved in 25 ml of sulfolane solution, and then the natural pine biomass material was added until submerged and impregnated under vacuum for 12 h.
[0052] Add 5.05g zinc sulfide, 0.50g ferric citrate, and 25ml sulfolane solution and stir to mix. Then, vacuum impregnate at 120℃ for 48h. After that, place the biomass material and the mixed solution into a high-pressure reactor and hydrothermally react at 110℃ for 24h. After natural cooling, take out the biomass material and ultrasonically clean it in 25ml sulfolane solution for 30min, then ultrasonically clean it in 35ml dichloromethane for 30min, then soak it in dichloromethane for 24h, and then vacuum dry it at 100℃ to obtain the natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0053] The biomass-based Fe-MOF-5 material obtained above was heated to 1000 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 7 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0054] Example 3
[0055] Natural paulownia wood was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural paulownia biomass material. 1.5 g of terephthalic acid was dissolved in 30 ml of methylpyrrolidone solution by stirring, and then the natural paulownia biomass material was added until submerged, and impregnated under vacuum for 24 h.
[0056] Add 7.58 g zinc nitrate, 0.6 g iron glycine, and 30 ml methylpyrrolidone solution and stir to mix. Then, vacuum impregnate at 90 °C for 45 h. After that, place the biomass material and the mixed solution into a high-pressure reactor and hydrothermally react at 120 °C for 24 h. After natural cooling, take out the biomass material and place it in 30 ml methylpyrrolidone solution for ultrasonic cleaning for 30 min, then ultrasonic cleaning with 45 ml dichloromethane for 30 min, then soak in dichloromethane for 24 h, and then vacuum dry at 90 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0057] The biomass-based Fe-MOF-5 material obtained above was heated to 900 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 2 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0058] Example 4
[0059] Natural cedar wood was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural cedar biomass material. 1.2 g of oxalic acid was dissolved in 60 ml of butyl acetate amine solution by stirring, and then the natural cedar biomass material was added until submerged, and vacuum impregnated for 12 h.
[0060] Add 16.84 g of zinc carbonate, 1.00 g of dicyclopentadiene iron, and 60 ml of butyl acetate solution and stir to mix. Then, vacuum impregnate at 115 °C for 36 h. After that, place the biomass material and its mixed solution into a high-pressure reactor and hydrothermally react at 100 °C for 72 h. After natural cooling, take out the biomass material and place it in 60 ml of butyl acetate solution for ultrasonic cleaning for 30 min, then ultrasonic cleaning with 30 ml of dichloromethane for 30 min, then soaking in dichloromethane for 24 h, and then vacuum drying at 110 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0061] The biomass-based Fe-MOF-5 material obtained above was heated to 1100 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 3 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0062] Example 5
[0063] Natural oak was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural oak biomass material. 1.2 g of formic acid was added to 55 ml of propyl propionate solution and stirred until dissolved. The natural oak biomass material was then added to the solution until submerged and impregnated under vacuum for 12 h.
[0064] Add 8.43 g zinc nitrate, 0.8 g iron acetylacetone, and 55 ml propyl propionate solution and stir to mix. Then, vacuum impregnate at 140 °C for 24 h. After that, place the biomass material and its mixed solution into a high-pressure reactor and hydrothermally react at 130 °C for 48 h. After natural cooling, take out the biomass material and place it in 55 ml propyl propionate solution for ultrasonic cleaning for 30 min, then ultrasonic cleaning with 60 ml dichloromethane for 30 min, then soak in dichloromethane for 24 h, and then vacuum dry to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0065] The biomass-based Fe-MOF-5 material obtained above was heated to 700 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 8 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0066] Example 6
[0067] Natural birch wood was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural birch biomass material. 1.0 g of terephthalic acid was dissolved in 20 ml of N,N-dimethylformamide solution by stirring, and then the natural birch biomass material was added until submerged, and vacuum impregnated for 36 h.
[0068] Then, 30.32 g of zinc sulfide, 0.9 g of ferric citrate, and 20 ml of N,N-dimethylformamide solution were added and stirred. The mixture was then vacuum impregnated at 130 °C for 36 h. After that, the biomass material and its mixed solution were placed in a high-pressure reactor and hydrothermally reacted at 140 °C for 36 h. After natural cooling, the biomass material was taken out and ultrasonically cleaned in 20 ml of N,N-dimethylformamide solution for 30 min, followed by ultrasonic cleaning with 40 ml of dichloromethane for 30 min. After that, it was soaked in dichloromethane for 24 h and then vacuum dried at 120 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0069] The biomass-based Fe-MOF-5 material obtained above was heated to 1500 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 9 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0070] Example 7
[0071] Natural eucalyptus wood was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural eucalyptus biomass. 1.0 g of isophthalic acid was dissolved in 60 ml of methylpyrrolidone solution by stirring, and then the natural eucalyptus biomass was added until submerged, and impregnated under vacuum for 12 h.
[0072] Add 9.85 g zinc sulfide, 0.5 g iron acetylacetonate, and 60 ml methylpyrrolidone solution and stir to mix. Then, vacuum impregnate at 120 °C for 24 h. After that, place the biomass material and its mixed solution in a high-pressure reactor and hydrothermally react at 140 °C for 72 h. After natural cooling, take out the biomass material and place it in 60 ml methylpyrrolidone solution for ultrasonic cleaning for 30 min, then ultrasonic cleaning with 60 ml dichloromethane for 30 min, then soak in dichloromethane for 24 h, and then vacuum dry at 130 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0073] The biomass-based Fe-MOF-5 material obtained above was heated to 1300 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 10 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0074] Example 8
[0075] Natural bamboo was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural bamboo biomass material. 1.0 g of isophthalic acid was dissolved in 50 ml of methylpyrrolidone solution by stirring, and then the natural eucalyptus biomass material was added until submerged and impregnated under vacuum for 24 h.
[0076] Then, 9.56 g of zinc sulfide, 0.68 g of acetylacetone iron, and 35 ml of methylpyrrolidone solution were added and stirred. The mixture was then vacuum impregnated at 130 °C for 48 h. After that, the biomass material and its mixed solution were placed in a high-pressure reactor and hydrothermally reacted at 130 °C for 72 h. After natural cooling, the biomass material was removed and ultrasonically cleaned in 60 ml of methylpyrrolidone solution for 30 min, followed by ultrasonic cleaning in 60 ml of dichloromethane for 30 min. After that, it was soaked in dichloromethane for 24 h and then vacuum dried at 130 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0077] The biomass-based Fe-MOF-5 material obtained above was heated to 1300 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 10 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0078] Example 9
[0079] Natural straw was cut perpendicular to its growth direction, then ultrasonically washed with anhydrous ethanol and deionized water to remove surface impurities and air-dried to obtain natural straw biomass material. 1.5 g of terephthalic acid was dissolved in 45 ml of methylpyrrolidone solution by stirring, and then the natural paulownia biomass material was added until submerged, and vacuum impregnated for 48 h.
[0080] Add 8.00 g zinc nitrate, 0.7 g iron glycine, and 30 ml methylpyrrolidone solution and stir to mix. Then, vacuum impregnate at 90 °C for 45 h. After that, place the biomass material and its mixed solution into a high-pressure reactor and hydrothermally react at 120 °C for 24 h. After natural cooling, take out the biomass material and place it in 30 ml methylpyrrolidone solution for ultrasonic cleaning for 30 min, then ultrasonic cleaning with 45 ml dichloromethane for 30 min, then soak in dichloromethane for 24 h, and then vacuum dry at 90 °C to obtain natural biomass material with in-situ grown Zn-Fe bimetallic MOF, namely biomass-based Fe-MOF-5 material.
[0081] The biomass-based Fe-MOF-5 material obtained above was heated to 900 °C at a heating rate of 5 °C / min under an Ar atmosphere of 100 ml / min and held at that temperature for 2 h. Then it was cooled to room temperature to obtain a biomass carbon-based Fe-MOF-5 composite catalyst.
[0082] like Figure 5 and Figure 6 As shown, the biomass carbon-based Fe-MOF-5 composite catalyst prepared by the method of this invention has electrochemical performance and hydrogen peroxide production that are far superior to other catalysts.
[0083] In summary, this invention selects natural biomass materials as carbon precursors for the electrochemical two-electron oxygen reduction reaction to produce hydrogen peroxide. A biomass-based carbon cathode material, biomass-based Fe-MOF-5, was prepared via a composite Zn-Fe bimetallic MOF catalyst and a simple carbonization process. By introducing Fe-MOF-5, the oxygen-containing functional groups of the biomass carbon, the active sites for electrocatalytic reactions, and the two-electron oxygen reduction selectivity are increased, which is beneficial for promoting hydrogen peroxide production and has great application potential in sustainable green synthesis of hydrogen peroxide and environmental remediation.
[0084] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit disclosed in the present invention should fall within the patent scope covered by the present invention.
Claims
1. A method for preparing a biomass carbon-based composite catalyst, characterized in that, Includes the following steps: S1. Pre-treat natural biomass materials by pre-impregnating the pre-treated biomass materials in the first solution; S2. The biomass material is immersed in the mixed solution, and the biomass material and the mixed solution undergo a hydrothermal reaction. The biomass material is then washed and vacuum dried to obtain biomass-based Fe-MOF-5 material. S3. Carbonize the biomass-based material at 700~1500℃ to obtain a biomass carbon-based Fe-MOF-5 composite catalyst; The mixed solution comprises iron-containing compounds, zinc-containing compounds, organic acids, and organic solvents. The method for preparing the mixed solution is as follows: The organic acid is dissolved in an organic solvent to form a first solution; Iron-containing organic compounds and zinc-containing organic compounds are dissolved in an organic solvent to form a second solution; The second solution is mixed with the first solution to form a mixed solution; The mass-to-volume ratio of organic acid to organic solvent in the mixed solution is 1~2:20~100 g / mL; The molar ratio of iron ions, zinc ions and organic acids in the mixed solution is 1:2~50:2~10; The iron-containing compound is at least one of dicyclopentadiene iron, ferric citrate, ferric acetylacetone, ferric glycine, ferric chloride, ferric nitrate, and ferric acetate; the zinc-containing compound is at least one of zinc carbonate, zinc sulfide, zinc sulfate, and zinc nitrate; the organic acid is at least one of isophthalic acid, terephthalic acid, benzoic acid, oxalic acid, formic acid, oxalic acid, and acetic acid; and the organic solvent is at least one of acetone, methanol, ethanol, cyclochloropropane, sulfolane, N,N-dimethylformamide, butyl acetate, methylpyrrolidone, propyl propionate, and dichloromethane. Natural biomass materials include at least one of the following: poplar, pine, paulownia, fir, oak, birch, eucalyptus, straw, bamboo, sugarcane bagasse, and reed.
2. The method of claim 1, wherein the biomass carbon-based composite catalyst is prepared by the steps of: The pretreatment method for natural biomass materials is as follows: cut the natural biomass materials perpendicular to the growth direction, ultrasonically wash them with anhydrous ethanol and deionized water to remove surface impurities, and then air dry them naturally to obtain pretreated biomass materials.
3. The method for preparing the biomass carbon-based composite catalyst according to claim 1, characterized in that, In step S1, the pre-impregnation time is 12~72 h; In step S2, the impregnation temperature is 100℃~150℃ and the impregnation time is 12~72 h; the hydrothermal reaction temperature is 90℃~150℃ and the hydrothermal reaction time is 12~72 h; the vacuum drying temperature is 80℃~130℃. In step S3, the carbonization time is 2~10 h.
4. A biomass carbon-based composite catalyst, characterized by, The biomass carbon-based composite catalyst is prepared by the method described in any one of claims 1 to 3 and serves as the cathode catalyst layer in the electrochemical two-electron oxygen reduction reaction to generate hydrogen peroxide.