Electrochemical generation device and method for preparing hydrogen peroxide

Abstract

The invention relates to an electrochemical generation device and a method for preparing hydrogen peroxide, the electrochemical generation device comprises an electrolysis module, and the electrolysis module comprises an electrolytic tank, an anode and an amphiphilic cathode; the amphiphilic cathode comprises a carbon felt substrate and active components loaded on the carbon felt substrate, and the active components comprise oxidized carbon black and polytetrafluoroethylene. According to the electrochemical generation device, under the condition that gas compression equipment is not additionally arranged, the interface mass transfer and three-phase interface catalytic performance of the amphiphilic cathode in the electrocatalytic oxygen reduction process is effectively improved, the electrode catalytic efficiency is improved, meanwhile, electrode surface denaturation and inactivation are reduced, and the yield of hydrogen peroxide is effectively improved.

Description

Technical Field

[0001] The present disclosure relates to environment, energy and electrochemical synthesis, and in particular, to an electrochemical generating device and a method for preparing hydrogen peroxide. Background Art

[0002] Hydrogen peroxide is one of the 100 most important chemicals currently. It has extremely high application value in the fields of bleaching and chemical synthesis, and can also be used as a potential energy carrier. It is crucial to produce hydrogen peroxide in an efficient, stable and low-energy manner. At present, the mainstream production process of hydrogen peroxide is the anthraquinone method. The disadvantages are that the method is complicated, there are hidden dangers in storage and transportation safety, there is pollution in the synthesis process, and the product contains organic residues. Therefore, electrochemical hydrogen peroxide preparation technology has attracted much attention as a green and clean alternative, and it is expected to make up for the shortcomings of the anthraquinone method in the hydrogen peroxide industry chain. However, in the current electrocatalytic system, the cathode oxygen reduction reaction is subject to the oxygen mass transfer efficiency and conversion efficiency, and the hydrogen peroxide output is low. Traditional hydrogen peroxide generators require external gas compression equipment to supply oxygen, while the gas diffusion electrode (GDE) has a small oxygen diffusion coefficient, a low gas conversion rate (less than 1%), a complex device and a high preparation cost, and there is a problem of energy waste. Amphiphilic gas active diffusion electrodes do not require additional aeration equipment. However, due to the complexity of the three-phase oxygen reduction reaction, there are problems with the balance and control of the few hydrophilic reaction active sites on the electrode and the hydrophobic gas channels that promote oxygen mass transfer. How to enhance the three-phase interface reaction activity while improving the oxygen mass transfer efficiency has become the key point of the problem. Summary of the invention

[0003] The purpose of the present disclosure is to provide an electrochemical generator and a method for preparing hydrogen peroxide, which can improve the interfacial mass transfer and three-phase interfacial catalytic performance of an amphiphilic cathode during the electrocatalytic oxygen reduction process, enhance the electrode catalytic efficiency, reduce electrode surface denaturation and deactivation, and effectively improve the yield of the product.

[0004] In order to achieve the above-mentioned objectives, the first aspect of the present disclosure provides an electrochemical generating device, which includes an electrolysis module, the electrolysis module comprises an electrolytic cell, an anode and an amphiphilic cathode; the amphiphilic cathode comprises a carbon felt substrate and oxidized carbon black and polytetrafluoroethylene loaded on the carbon felt substrate.

[0005] Optionally, in the amphiphilic cathode, the loading amount of the active component is 0.5 to 3 mg / cm 2 .

[0006] Optionally, the method for preparing the amphiphilic cathode comprises the following steps:

[0007] S1: mixing oxidized carbon black, polytetrafluoroethylene and a solvent to form a slurry;

[0008] S2: using the slurry to perform a drip coating process, a drying process and a first calcination process on the carbon felt after the hydrophilic pretreatment.

[0009] Optionally, in step S1, the mass ratio of the polytetrafluoroethylene to the oxidized carbon black is 0.2 to 2.5:1, preferably 0.6 to 1.8:1; the solvent includes water and an organic solvent, and the organic solvent is selected from one or more of ethanol, acetone and N,N-dimethylformamide.

[0010] Optionally, the mass content of oxygen in the oxidized carbon black is 1.0 to 7.5%, preferably 3.9 to 6.8%.

[0011] Optionally, in step S2, the concentration of the slurry is 0.0005-0.03 g / mL, preferably 0.002-0.005 g / mL; the drop coating process includes applying the slurry at a rate of 5-20 uL / cm 2 The amount of drop coating is added to the carbon oxide felt, and the drop coating amount is preferably 10 to 15 uL / cm 2 , the dripping treatment and the drying treatment are repeated 1 to 10 times, preferably 3 to 5 times;

[0012] The conditions of the first calcination treatment include: the temperature of the first calcination is 300-400° C., preferably 300-320° C.; the time of the first calcination is 0.25-1 h, preferably 0.3-0.6 h; and the first calcination is performed under an inert atmosphere.

[0013] Optionally, the electrochemical generating device further comprises an ultrasonic module, and the electrolysis module is located in the ultrasonic field of the ultrasonic module.

[0014] Optionally, the lower part of the amphiphilic cathode is placed in an electrolyte, and the upper part is in contact with an oxygen-containing gas; the oxygen-containing gas includes air; the material of the anode is selected from one or more of metals, metal oxides and carbon-based materials, the metal includes one or more of platinum, titanium and stainless steel; the metal oxide includes one or more of titanium oxide, tin oxide and nickel oxide; the carbon-based material is selected from one or more of carbon rods, carbon felt and carbon cloth.

[0015] A second aspect of the present disclosure provides a method for preparing hydrogen peroxide using the electrochemical generator described in the first aspect of the present disclosure.

[0016] Optionally, the preparation conditions include: ultrasonic power of 100 to 900 W, preferably 400 to 700 W; and electrolysis at a temperature of 10 to 30° C., preferably 15 to 25° C.

[0017] Through the above technical scheme, the electrolysis module of the electrochemical generating device disclosed in the present invention uses an amphiphilic cathode with higher porosity and more two-electron oxygen reduction reaction active sites. Without adding an external gas compression device, the interfacial mass transfer and catalytic performance of the amphiphilic cathode in the electrocatalytic oxygen reduction process are effectively improved, the excessive adhesion of gas to the active sites is avoided, the three-phase interface catalytic efficiency is improved, and at the same time, the denaturation and deactivation of the electrode surface is reduced, effectively increasing the yield of hydrogen peroxide.

[0018] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0020] Figure 1 It is a schematic diagram of an electrochemical generating device according to one embodiment of the present disclosure.

[0021] Figure 2 4 is a comparison chart of the hydrogen peroxide yields of the electrochemical generators F1 and F8 disclosed in the present invention.

[0022] Figure 3 Graph showing the electrochemical stability of the electrochemical generator F1 of the present disclosure. DETAILED DESCRIPTION

[0023] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0024] A first aspect of the present disclosure provides an electrochemical generating device, which includes an electrolysis module, wherein the electrolysis module includes an electrolytic cell, an anode, and an amphiphilic cathode; the amphiphilic cathode includes a carbon felt substrate and an active component loaded on the carbon felt substrate, wherein the active component includes oxidized carbon black and polytetrafluoroethylene.

[0025] The electrolysis module of the electrochemical generator disclosed in the present invention uses an amphiphilic cathode with higher porosity and more two-electron oxygen reduction reaction active sites. Without adding gas compression equipment, the interfacial mass transfer and catalytic performance of the amphiphilic cathode in the electrocatalytic oxygen reduction process are effectively improved, the electrode catalytic efficiency is improved, and at the same time, the denaturation and deactivation of the electrode surface are reduced, thereby effectively increasing the yield of hydrogen peroxide.

[0026] According to one embodiment of the present disclosure, in the amphiphilic cathode, the loading amount of the active component is 0.5 to 20 mg / cm 2 , preferably 0.5 to 10 mg / cm2 , more preferably 0.5 to 3 mg / cm 2 The above-mentioned implementation is conducive to the prepared amphiphilic cathode having higher electrochemical activity and smaller overpotential, which further makes the yield of hydrogen peroxide higher.

[0027] According to one embodiment of the present disclosure, a method for preparing an amphiphilic cathode comprises the following steps:

[0028] S1: mixing oxidized carbon black, polytetrafluoroethylene and a solvent to form a slurry;

[0029] S2: using the slurry to perform a drip coating process, a drying process and a first calcination process on the carbon felt after the hydrophilic pretreatment.

[0030] According to one embodiment of the present disclosure, in step S1, the mass ratio of polytetrafluoroethylene to the oxidized carbon black is 0.2 to 2.5:1, preferably 0.6 to 1.8:1; the solvent includes water and an organic solvent, and the organic solvent is selected from one or more of ethanol, acetone and N,N-dimethylformamide. In the solvent, the mass fraction of the organic solvent is not particularly limited, and the oxidized carbon black and polytetrafluoroethylene are uniformly dispersed in the solvent. The above-mentioned embodiment is conducive to the obtained amphiphilic cathode having higher electrochemical activity and smaller overpotential, which further makes the yield of hydrogen peroxide higher.

[0031] According to an embodiment of the present disclosure, the mass content of oxygen in the oxidized carbon black is 1.0 to 7.5%, preferably 3.9 to 6.8%. The above embodiment is conducive to the prepared amphiphilic cathode having higher electrochemical activity and smaller overpotential, further making the yield of hydrogen peroxide higher.

[0032] According to an embodiment of the present disclosure, in step S1, the oxidized carbon black is subjected to a second calcination treatment by placing the carbon black in air; the conditions of the second calcination treatment include: the second calcination temperature is 200-650°C, preferably 500-600°C; the second calcination time is 0.5-2.5h, preferably 1-2h. The above embodiment is conducive to the prepared amphiphilic cathode having higher electrochemical activity and smaller overpotential, further making the yield of hydrogen peroxide higher.

[0033] According to one embodiment of the present disclosure, in step S2, the hydrophilic pretreatment includes subjecting the carbon felt to a third calcination treatment in an air atmosphere, wherein the temperature of the third calcination is 300 to 500°C, and the time of the third calcination is 0.5 to 3 hours; the concentration of the slurry is 0.0005 to 0.03 g / mL, preferably 0.002 to 0.005 g / mL; the drip coating treatment includes applying the slurry at a rate of 5 to 20 uL / cm 2The amount of drop coating is added to the carbon oxide felt, and the drop coating amount is preferably 10 to 15 uL / cm 2 , the drip coating process and the drying process are repeated 1 to 10 times, preferably 3 to 5 times; the conditions of the first calcination process include: the temperature of the first calcination is 300 to 400°C, preferably 300 to 320°C; the time of the first calcination is 0.25 to 1h, preferably 0.3 to 0.6h; the first calcination is carried out under an inert atmosphere. The inert atmosphere includes one or more of nitrogen and argon. The above-mentioned embodiment is conducive to the prepared amphiphilic cathode having higher electrochemical activity and smaller overpotential, which further makes the yield of hydrogen peroxide higher.

[0034] According to one embodiment of the present disclosure, the electrochemical generating device also includes an ultrasonic module, and the electrolytic module is in the ultrasonic field of the ultrasonic module; the ultrasonic module includes a flow trough, and the flow trough includes a medium inlet and a medium outlet. The temperature of the medium in the flow trough is kept constant, and the temperature can be 10 to 30°C; the lower part of the electrolytic cell is in the flow trough.

[0035] According to one embodiment of the present disclosure, the lower part of the amphiphilic cathode is placed in an electrolyte, and the upper part is in contact with an oxygen-containing gas; the oxygen-containing gas includes air; the material of the anode is selected from one or more of metals, metal oxides and carbon-based materials, and the metal includes one or more of platinum, titanium and stainless steel; the metal oxide includes one or more of titanium oxide, tin oxide and nickel oxide; the carbon-based material is selected from one or more of carbon rods, carbon felt and carbon cloth.

[0036] A second aspect of the present disclosure provides a method for preparing hydrogen peroxide using the electrochemical generator described in the first aspect of the present disclosure.

[0037] According to one embodiment of the present disclosure, the preparation conditions include: ultrasonic power of 100 to 900 W, preferably 400 to 700 W; electrolysis is carried out at a temperature of 10 to 30° C., preferably 15 to 25° C.

[0038] According to one embodiment of the present disclosure, the electrochemical generating device can also be used to prepare water.

[0039] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0040] The polytetrafluoroethylene used in the examples and comparative examples of the present application is a product purchased from Innochem with the brand number 9002-84-0 (the mass fraction of polytetrafluoroethylene is 60%). Unless otherwise specified, the reagents used in the present disclosure are all commercially available products.

[0041] The mass content of oxygen in oxidized carbon black was tested by XPS, the instrument model was PHI 5600;

[0042] The electrochemical performance was carried out on a CHI 760D electrochemical workstation.

[0043] Preparation Example 1

[0044] The carbon black was placed in air and calcined at temperatures of 450°C and 550°C for 1.5 hours to obtain oxidized carbon black with oxygen contents of 2.34% and 4.58%.

[0045] Example 1

[0046] In this embodiment, oxidized carbon black with an oxygen content of 4.58% was used;

[0047] S1: polytetrafluoroethylene and oxidized carbon black were mixed with 5 mL of water and 15 mL of ethanol in a mass ratio of 1.2:1 to form a slurry;

[0048] S2: placing a carbon felt with a thickness of 2 mm in an air atmosphere and calcining it at a temperature of 400° C. for 1.5 h to obtain a carbon felt after hydrophilic pretreatment;

[0049] The hydrophilic pretreated carbon felt was placed in a watch glass as a substrate, and a slurry with a concentration of 0.0035 g / mL was added at a rate of 10 uL / cm 2 The coating amount was drop-coated on the oxidized carbon felt and dried at 80°C for 10 min. The drop-coating and drying processes were repeated 4 times, and then calcined to obtain an amphiphilic cathode.

[0050] The calcination treatment in S2 is carried out under an inert atmosphere of nitrogen, the calcination time is 0.5 h, and the calcination temperature is 300°C.

[0051] Example 2

[0052] The method of this embodiment is the same as that of embodiment 1, except that oxidized carbon black having an oxygen content of 2.34% is used.

[0053] Example 3

[0054] The method of this embodiment is the same as that of Embodiment 1, except that in step S1, the mass ratio of polytetrafluoroethylene to oxidized carbon black is 2.4:1.

[0055] Example 4

[0056] The method of this embodiment is the same as that of embodiment 1, except that in step S2, 0.0015 g / mL slurry is dripped at 20 uL / cm 2 And dry, repeat 2 times.

[0057] Example 5

[0058] The method of this embodiment is the same as that of embodiment 1, except that in step S2, the calcination time is 0.5 h and the calcination temperature is 340°C.

[0059] Comparative Example 1

[0060] In this comparative example, carbon black was used to replace oxidized carbon black.

[0061] S1: Mix polytetrafluoroethylene and carbon black with 5 mL of water and 15 mL of ethanol in a mass ratio of 1.2:1 to form a slurry;

[0062] S2: placing the carbon felt with a thickness of 2 mm in an air atmosphere and calcining it at a temperature of 400° C. for 1.5 h to obtain the carbon felt after hydrophilic pretreatment;

[0063] The hydrophilic pretreated carbon felt was placed in a surface dish as a substrate, and 10 uL / cm2 of slurry with a concentration of 0.0035 g / mL was added dropwise. 2 The process of drying, drip coating and drying was repeated 4 times, and then calcined to obtain an amphiphilic cathode.

[0064] The drying temperature is 80°C and the drying time is 10 min. The calcination treatment in S2 is carried out under an inert atmosphere of nitrogen. The calcination time is 0.5 h and the calcination temperature is 300°C.

[0065] Reaction Examples 1 to 6

[0066] The amphiphilic cathodes prepared in Examples 1 to 5 and Comparative Example 1 are respectively assembled into electrochemical generating devices F1 to F6, wherein the anode of the electrochemical generating device is a platinum wire; the electrochemical generating device comprises an electrolysis module and an ultrasonic module, wherein the electrolysis module comprises an electrolytic cell, an anode, and the amphiphilic cathodes in Examples 1 to 5 and Comparative Example 1; the lower part of the amphiphilic cathode is placed in the electrolyte, and the upper part is in contact with the air; the ultrasonic module comprises a flow tank, the flow tank comprises a medium inlet and a medium outlet, a flowing ultrasonic field is formed in the flow tank, and the lower part of the electrolytic cell is in the flow tank;

[0067] The electrochemical generator was used to prepare hydrogen peroxide in a 0.1 M NaOH solution, with the circulating water temperature maintained at 25° C. and the ultrasonic power at 600 W. The yield of hydrogen peroxide at a voltage of 1.7 V is listed in Table 1.

[0068] Reaction Example 7

[0069] The amphiphilic cathode prepared in Example 1 was assembled into an electrochemical generator F1 to prepare hydrogen peroxide in a 0.1M NaOH solution, with the circulating water temperature maintained at 40°C and the ultrasonic power at 800 W. The yield of hydrogen peroxide at a voltage of 1.7 V is listed in Table 1.

[0070] Reaction Example 8

[0071] The amphiphilic cathodes prepared in Example 1 were respectively assembled into electrochemical generating devices F8, and the difference between the electrochemical generating devices F8 and F1 was that F8 did not include an ultrasonic module;

[0072] The electrochemical generator F8 was placed in a 0.1M NaOH solution to prepare hydrogen peroxide, the circulating water temperature was maintained at 25°C, and the ultrasonic power was 600 W. The yield of hydrogen peroxide at a voltage of 1.7 V is listed in Table 1.

[0073] Test Case

[0074] The catalytic performance of the amphiphilic cathodes of Examples 1 to 5 and Comparative Example 1 was tested. The test method used was to use a platinum wire as a counter electrode, test the hydrogen peroxide yield at a constant voltage of 1.7 V, and titrate the amount of product hydrogen peroxide using potassium permanganate titration; using a saturated calomel electrode as a reference electrode, without iR compensation, the test current density was 10 mA / cm 2 The overpotential under the condition is calculated, and the results are listed in Table 1; at the same time, the carbon felts without drip coating treatment and the carbon felts after drip coating treatment and the first calcination treatment of Examples 1 to 5 and Comparative Example 1 are weighed, and the loading amount of the active components is calculated, and the results are listed in Table 1.

[0075] Table 1

[0076]

[0077] According to the data in Table 1, the electrochemical device disclosed in the present invention has good electrochemical activity and can improve the yield of hydrogen peroxide.

[0078] By comparing Reaction Example 1 and Reaction Example 2, it can be seen that within the preferred oxygen content range of the oxidized carbon black disclosed in the present invention, the prepared amphiphilic cathode has higher electrochemical activity, smaller overpotential, and higher yield of hydrogen peroxide. At the same time, the amphiphilic cathode in Reaction Example 1 has no significant change in voltage during constant current operation and has good stability. By comparing Reaction Example 1 and Reaction Example 3, it can be seen that within the preferred mass ratio range of the oxidized carbon black to polytetrafluoroethylene disclosed in the present invention, the prepared amphiphilic cathode has higher electrochemical activity, smaller overpotential, and higher yield of hydrogen peroxide. High; by comparing reaction examples 1, 4 and 5, it can be seen that within the preferred drip coating conditions and the first calcination conditions of the present invention, the prepared amphiphilic cathode has higher electrochemical activity, smaller overpotential, and higher yield of hydrogen peroxide; by comparing reaction examples 1 and 7, it can be seen that within the preferred ultrasonic conditions of the present invention, the yield of hydrogen peroxide is higher; by comparing reaction examples 1 and 8, it can be seen that when the electrochemical device of the present invention includes an ultrasonic module, the electrochemical activity of the amphiphilic cathode is higher, the overpotential is smaller, and the yield of hydrogen peroxide is higher.

[0079] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0080] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0081] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. An electrochemical generating device, characterized in that: The electrochemical generating device comprises an electrolysis module, wherein the electrolysis module comprises an electrolytic cell, an anode and an amphiphilic cathode; The amphiphilic cathode comprises a carbon felt substrate and an active component supported on the carbon felt substrate, wherein the active component comprises oxidized carbon black and polytetrafluoroethylene.

2. The electrochemical generator according to claim 1, wherein: In the amphiphilic cathode, the loading amount of the active component is 0.5 to 3 mg / cm 2 .

3. The electrochemical generating device according to claim 1 or 2, wherein: The method for preparing the amphiphilic cathode comprises the following steps: S1: mixing oxidized carbon black, polytetrafluoroethylene and a solvent to form a slurry; S2: using the slurry to perform a drip coating process, a drying process and a first calcination process on the carbon felt after the hydrophilic pretreatment.

4. The electrochemical generating device according to claim 3, wherein: In step S1, the mass ratio of the polytetrafluoroethylene to the oxidized carbon black is 0.2 to 2.5:1, preferably 0.6 to 1.8:1; the solvent includes water and an organic solvent, and the organic solvent is selected from one or more of ethanol, acetone and N,N-dimethylformamide.

5. The electrochemical generating device according to claim 3, wherein: The mass content of oxygen in the oxidized carbon black is 1.0 to 7.5%, preferably 3.9 to 6.8%.

6. The electrochemical generating device according to claim 3, wherein: In step S2, the concentration of the slurry is 0.0005-0.03 g / mL, preferably 0.002-0.005 g / mL; the drop coating process includes applying the slurry at a rate of 5-20 uL / cm 2 The amount of drop coating is added to the carbon oxide felt, and the drop coating amount is preferably 10 to 15 uL / cm 2 , the dripping treatment and the drying treatment are repeated 1 to 10 times, preferably 3 to 5 times; The conditions of the first calcination treatment include: the temperature of the first calcination is 300-400° C., preferably 300-320° C.; the time of the first calcination is 0.25-1 h, preferably 0.3-0.6 h; and the first calcination is performed under an inert atmosphere.

7. The electrochemical generating device according to claim 1, wherein: The electrochemical generating device further comprises an ultrasonic module, and the electrolysis module is located in the ultrasonic field of the ultrasonic module.

8. The electrochemical generating device according to claim 1, wherein: The lower part of the amphiphilic cathode is placed in the electrolyte, and the upper part is in contact with the oxygen-containing gas; the oxygen-containing gas includes air; the material of the anode is selected from one or more of metals, metal oxides and carbon-based materials, the metal includes one or more of platinum, titanium and stainless steel; the metal oxide includes one or more of titanium oxide, tin oxide and nickel oxide; the carbon-based material is selected from one or more of carbon rods, carbon felt and carbon cloth.

9. A method for preparing hydrogen peroxide using the electrochemical generator according to any one of claims 1 to 8.

10. The method for preparing hydrogen peroxide according to claim 9, wherein: The preparation conditions include: ultrasonic power of 100-900W, preferably 400-700W; electrolysis is carried out at a temperature of 10-30°C, preferably 15-25°C.

Images