Aptes modified cfp anode material and method for water oxidation electro-synthesis of h2o2 using the same
By introducing APTES on the surface of carbon fiber paper to form SAMs and adjusting the binding energy between the active sites and water oxidation intermediates, the problems of high 2e-WOR overpotential or low yield in the existing electrochemical synthesis of H2O2 were solved, and efficient H2O2 production was achieved.
Patent Information
- Application Number
- CN202310090976.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-01-19
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2043-01-19
AI Technical Summary
In existing electrochemical methods for synthesizing H2O2, the two-electron water oxidation reaction (2e-WOR) at the anode has a high overpotential or a low H2O2 yield, and the application of carbon-based catalysts and metal oxides generally has problems, which limits the efficient production of H2O2.
3-Aminopropyl-3-ethoxysilane (APTES) was used to modify the surface of carbon fiber paper (CFP) to form self-assembled monolayers (SAMs). Specific functional groups were introduced into the CFP anode material to regulate the binding energy between the active sites and the water oxidation intermediate *OH, thereby improving the selectivity and yield of H2O2.
By modifying the CFP anode material with APTES, the selectivity and yield of H2O2 were significantly improved, and efficient water oxidation electrosynthesis of H2O2 was achieved, which has good stability and application prospects.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of electrochemical technology, and in particular relates to an APTES-modified CFP anode material and a method for electrosynthesizing H2O2 by water oxidation using the same. Background Art
[0002] H2O2 is one of the most important basic chemicals in modern chemical industry, sustainable energy conversion / storage, and environmental remediation, playing a vital role in production and daily life. According to statistics, the global demand for H2O2 exceeds 3 million tons per year. The anthraquinone process is the most mature method for producing H2O2. Currently, 90% of the world's H2O2 production uses the anthraquinone process, with product concentrations reaching 70 wt.%. However, the anthraquinone process produces a large amount of waste, requires complex, large-scale infrastructure, consumes a lot of energy, and has cumbersome separation and purification procedures. In addition, the transportation and storage of H2O2 pose safety risks, making decentralized H2O2 production more attractive.
[0003] Electrochemical synthesis of H2O2 is a method for decentralized production of H2O2 with good application prospects. It has obvious advantages such as simple equipment, controllable production scale, and mild process conditions. The production process is green and environmentally friendly, using electricity generated by sustainable energy as energy and H2O / O2 as raw materials. The electrochemical synthesis of H2O2 can be carried out through two pathways: the two-electron oxygen reduction reaction (2e-ORR, Formula 1) at the cathode and the two-electron water oxidation reaction (2e-WOR, Formula 2) at the anode. Since the reaction potential of 2e-WOR is higher than that of the four-electron water oxidation reaction (OER, Formula 3), water oxidation to produce H2O2 is not thermodynamically dominant. At present, research on the electrochemical synthesis of H2O2 mainly focuses on 2e-ORR. In recent years, it has been found that CO3 2- / HCO 3- Electrolytes can improve the performance of 2e-WOR, and many carbon-based catalysts and metal oxides have been developed, including BDD, PTFE-coated CFP, ZnO, and CaSnO3. However, their applications generally suffer from high overpotential or low H2O2 yield.
[0004] O2+2H + +2e － →H2O2, E o =0.67V vs.SHE, (1);
[0005] 2H2O→H2O2+2H + +2e － , E o =1.76V vs.SHE, (2);
[0006] 2H2O→O2+4H + +4e －, E o =1.23V vs.SHE, (3);
[0007] *+H2O→OH*+(H + +e - ), (4);
[0008] OH*+H2O→H2O2+(H + +e - )+*, (5);
[0009] OH*→O*+(H + +e - ) (6)
[0010] O*+H2O→OOH*+(H + +e - ) (7)
[0011] OOH*→*+O2+(H + +e - ) (8)
[0012] *Indicates a smooth catalyst surface.
[0013] Self-assembled monolayers (SAMs) can form strong chemical bonds with substrates, spontaneously forming on solid substrates at solid-liquid or solid-gas interfaces. This process simultaneously introduces specific functional groups onto the substrate surface. Because SAMs have limited effects on the intrinsic properties of substrates, SAM modification is often used to study the influence of functional groups on reaction processes. Combining SAMs with electrochemical H2O2 synthesis would open new avenues for H2O2 synthesis and hold great research value. Summary of the Invention
[0014] In view of this, in order to further explore the process of combining SAMs with electrochemical synthesis of H2O2, the present invention provides an APTES-modified CFP anode material and a method for electrosynthesizing H2O2 by water oxidation using the same. By using a SAMs - 3-aminopropyl-3-ethoxysilane (APTES) to modify carbon fiber paper (CFP), specific functional groups are introduced on its surface to obtain a modified CFP anode material. The anode material can adjust the binding energy between the active site and the water oxidation intermediate *OH, thereby improving the selectivity and yield of 2e-WOR electrosynthesis of H2O2.
[0015] In order to achieve the above technical objectives, the technical solutions adopted in this application are as follows:
[0016] In a first aspect, the present invention provides an APTES-modified CFP anode material, which is obtained by depositing 3-aminopropyl-3-ethoxysilane (APTES) on the surface of an oxidized carbon fiber paper (CFP).
[0017] Furthermore, the oxidized carbon fiber paper is obtained by oxidizing the carbon fiber paper with an acidic oxidant.
[0018] Furthermore, the preparation method of the oxidized carbon fiber paper includes: immersing the carbon fiber paper in an acidic oxidant, oxidizing the carbon fiber paper at 50-60° C. for 2-3 hours, and then washing the carbon fiber paper with deionized water and drying it.
[0019] Furthermore, the acidic oxidant is selected from concentrated nitric acid with a mass concentration of 50-60%, concentrated sulfuric acid with a mass concentration of 98%, or a mixture of concentrated sulfuric acid with a mass concentration of 98% and H2O2 solution with a mass concentration of 30% in a volume ratio of 7:3.
[0020] Furthermore, the carbon fiber paper is pretreated before oxidation treatment, which includes: cutting the carbon fiber paper into small pieces of 1×2 cm, ultrasonically cleaning them in 0.5M NaOH solution, 0.5M H2SO4 solution, ethanol and deionized water for 20 to 30 minutes, and then drying them.
[0021] Furthermore, the control parameters of the drying are: vacuum 100-133 Pa, temperature 70-80° C., and drying time not less than 10 hours.
[0022] Furthermore, the step of depositing 3-aminopropyl-3-ethoxysilane (APTES) on the surface of the oxidized carbon fiber paper (CFP) comprises:
[0023] The oxidized carbon fiber paper was placed vertically in a hydrothermal reactor. An open glass bottle containing APTES was placed in the hydrothermal reactor. The hydrothermal reactor was then filled with protective gas and sealed.
[0024] Heat the hydrothermal reactor to 160-200°C, keep it warm for 1-10 hours, and then cool it naturally to room temperature;
[0025] The carbon fiber paper on which 3-aminopropyl-3-ethoxysilane was deposited was taken out and dried to obtain the product.
[0026] Preferably, the hydrothermal reactor is heated to 175-190° C., kept warm for 3.5-4.5 hours, and then naturally cooled to room temperature.
[0027] Furthermore, the control parameters of the drying are: vacuum 100-133 Pa, temperature 50-60° C., and drying time 2-3 h.
[0028] In a second aspect, the present invention provides the use of the above-mentioned anode material in electro-oxidation catalytic reactions.
[0029] In a third aspect, the present invention provides a method for electrosynthesizing H2O2 by water oxidation, which uses the above-mentioned anode material. The method includes: using the anode material as the anode and a platinum sheet as the cathode, electrolyzing and preparing H2O2 in an electrolyte, and the reaction equation is: 2H2O→H2O2+H2.
[0030] Furthermore, the electrolyte is a K2CO3 solution with a concentration of 1 to 4 M, preferably a 4 M K2CO3 solution.
[0031] The present invention develops an APTES-CFP material, which has the property that APTES molecules self-assemble on the CFP surface to form a monolayer film. The material can be used as an anode material for electro-oxidation catalytic reactions. When participating in the electro-synthesis of H2O2 by water oxidation, the selectivity and yield of H2O2 can be improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Figure 1 These are microscopic morphologies of APTES-CFP obtained in Example 1 of the present invention, wherein Figure a is a SEM image, Figure b is an EDS image, and Figure c is an AFM image.
[0033] Figure 2 Figure 2 shows the effects of different reaction times and reaction temperatures on the selectivity of H2O2 in Example 2 of the present invention, wherein Figure a shows the effects of different reaction times, and Figure b shows the effects of different reaction temperatures.
[0034] Figure 3 The effects of different electrolyte concentrations on the H2O2 generation rate (Figure a) and selectivity (Figure b) in Example 3 of the present invention, as well as the stability of the APTES-modified electrode (Figure c). DETAILED DESCRIPTION
[0035] In the description of the present invention, it should be noted that if specific conditions are not specified in the examples, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.
[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, which are intended to explain the present invention rather than to limit it.
[0037] Example 1
[0038] This embodiment provides an APTES-modified CFP anode material, which is obtained by depositing 3-aminopropyl-3-ethoxysilane (APTES) on the surface of oxidized carbon fiber paper (CFP). The specific preparation method is as follows:
[0039] 1) CFP preprocessing
[0040] The CFP was cut into small pieces of 1×2 cm, ultrasonically cleaned in 0.5 M NaOH, 0.5 M H2SO4, ethanol and deionized water for 30 min in sequence, and then dried in a vacuum oven at 80 °C overnight.
[0041] 2) Oxidation treatment of CFP
[0042] The CFP obtained in step 1) is oxidized in 60% concentrated HNO3 at 60°C for 3 hours. The CFP is then thoroughly rinsed with deionized water and dried overnight in a vacuum oven at 80°C at a vacuum of 100-133 Pa. The concentrated HNO3 strong acid oxidant in this step can also be replaced with 98% concentrated sulfuric acid or a mixture of 98% concentrated sulfuric acid and 30% H2O2 solution in a volume ratio of 7:3.
[0043] 3) APTES-modified CFP
[0044] The CFP obtained in step 2) is placed vertically in a hydrothermal reactor with a volume of 50 mL and an inner lining of polytetrafluoroethylene, and a glass bottle with a volume of 2 mL containing 100 μL APTES is placed in the reactor. Fill the reactor with argon, and then tighten the stainless steel shell cover. Place the entire hydrothermal reactor in an oven and heat it to 180°C. After storing for 4 hours, cool it naturally to room temperature. Take out the CFP, dry it in a vacuum oven at 60°C for 2 hours, remove the excess APTES on the CFP, and obtain APTES-modified CFP (APTES-CFP). The micromorphology of the material is shown in the figure below. Figure 1 As shown, Figure a is the SEM image, Figure b is the EDS image, and Figure c is the AFM image, indicating that APTES successfully modified the CFP material.
[0045] Example 2
[0046] This example investigates the effects of APTES-CFP obtained at different reaction times and reaction temperatures in step 3) of Example 1 on the electrosynthesis of H2O2 by water oxidation. The specific operations of steps 1) to 3) are the same as those in Example 1. Then, the APTES-CFP materials obtained at different reaction times and reaction temperatures are used as anodes and platinum sheets are used as cathodes to electrolyze H2O2 in a 1M K2CO3 solution. The voltage used is 2.8 V, and the electrolysis is terminated when the total reaction charge reaches 10C or the electrolysis time reaches 10 min.
[0047] Among them, when examining the effect of the reaction time (2h, 3h, 4h, 6h, 8h) in step 3), the reaction temperature adopted was 160°C; when examining the effect of the reaction temperature (140°C, 160°C, 180°C, 200°C), the reaction time adopted was 4h.
[0048] Determination of H2O2 concentration: After the electrolysis reaction is complete, take 0.5 mL of electrolyte and add 0.5 mL of 3M H2SO4 to acidify it. Then, add 0.5 mL of 0.05M potassium titanium oxalate solution. After standing for 10 minutes, measure the absorbance and convert the H2O2 concentration according to the standard curve.
[0049] The results are as follows Figure 2 As shown, it is shown that when the reaction time is about 4 hours and the reaction temperature is about 180°C, it is the optimal preparation condition for APTES-modified CFP. Therefore, the present invention preferably heats the hydrothermal reactor to 175-190°C and keeps it warm for 3.5-4.5 hours.
[0050] Example 3
[0051] This example investigates the effect of varying K2CO3 electrolyte concentrations on the electrochemical synthesis of H2O2 using an APTES-CFP electrode. Using the optimal APTES-modified CFP preparation conditions obtained in Example 2 and following the procedure of Example 1, an APTES-CFP electrode was prepared as the anode, and a platinum sheet as the cathode. H2O2 was electrochemically synthesized in K2CO3 solutions of varying concentrations. Electrolysis was terminated when the total reaction charge reached 10C or the electrolysis time reached 10 minutes.
[0052] Determination of H2O2 concentration: After the reaction is complete, take 0.5 mL of electrolyte and add 0.5 mL of 3M H2SO4 to acidify. Then, add 0.5 mL of 0.05M potassium titanium oxalate solution. After standing for 10 minutes, measure the absorbance and convert the H2O2 concentration according to the standard curve.
[0053] The results are as follows Figure 3 As shown in the figure, it is shown that with the increase of K2CO3 concentration, the generation rate and selectivity of H2O2 increase accordingly. The maximum generation rate can reach 80μmol L -1 min -1 cm -2 (Figure a), and the selectivity can reach 83% (Figure b). In addition, the electrode can operate stably for up to 12 hours (Figure c), showing good practical application prospects.
[0054] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.
Claims
1. APTES modified CFP anode material, characterized by: It is obtained by depositing 3-aminopropyl-3-ethoxysilane on the surface of oxidized carbon fiber paper; The method of depositing 3-aminopropyl-3-ethoxysilane on the surface of the oxidized carbon fiber paper comprises: The oxidized carbon fiber paper was placed vertically in a hydrothermal reactor. An open glass bottle containing APTES was placed in the hydrothermal reactor. The hydrothermal reactor was then filled with protective gas and sealed. Heat the hydrothermal reactor to 175-190°C, keep it warm for 3.5-4.5 hours, and then cool it naturally to room temperature; The carbon fiber paper on which 3-aminopropyl-3-ethoxysilane was deposited was taken out and dried to obtain the product.
2. The APTES-modified CFP anode material according to claim 1, characterized in that: The oxidized carbon fiber paper is obtained by oxidizing the carbon fiber paper with an acidic oxidant.
3. The APTES-modified CFP anode material according to claim 1 or 2, characterized in that: The preparation method of the oxidized carbon fiber paper comprises: immersing the carbon fiber paper in an acidic oxidant, oxidizing the carbon fiber paper at 50-60° C. for 2-3 hours, and then washing the carbon fiber paper with deionized water and drying it.
4. The APTES-modified CFP anode material according to claim 3, characterized in that: The acidic oxidant is selected from concentrated nitric acid with a mass concentration of 50-60%, concentrated sulfuric acid with a mass concentration of 98%, or a mixture of concentrated sulfuric acid with a mass concentration of 98% and H2O2 solution with a mass concentration of 30% in a volume ratio of 7:
3.
5. The APTES-modified CFP anode material according to claim 1, characterized in that: The carbon fiber paper was pretreated before oxidation treatment. The pretreatment included cutting the carbon fiber paper into small pieces of 1×2 cm, ultrasonically cleaning them in 0.5 M NaOH, 0.5 M H2SO4, ethanol and deionized water for 20 to 30 min, and then drying them.
6. Use of the anode material according to any one of claims 1 to 5 in the 2e-WOR electrosynthesis of H2O2 reaction.
7. A method for electrosynthesis of H2O2 by water oxidation, characterized in that: The anode material according to any one of claims 1 to 5 is used, and the method comprises: using the anode material as an anode and a platinum sheet as a cathode, and performing electrolysis in an electrolyte to prepare H2O2, and the reaction equation is: 2H2O → H2O2 + H2.
8. The method for electrosynthesis of H2O2 by water oxidation according to claim 7, characterized in that: The electrolyte is a K2CO3 solution with a concentration of 1-4M.