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A gas diffusion electrode and its preparation method

A gas diffusion electrode and gas diffusion layer technology, applied in the direction of electrodes, electrode shapes/types, electrolysis components, etc., can solve the problems of difficult gas-liquid-solid three-phase reaction balance, weak electrode mechanical strength, and difficulty in industrialized production, etc. The effect of reducing the ability of hydrogen peroxide side reaction, excellent water pressure resistance, and improving electrocatalytic ability

Active Publication Date: 2017-04-05
BEIJING UNIV OF CHEM TECH
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Problems solved by technology

[0014] 2) During the electrochemical reaction of the oxygen cathode, due to the influence of the electrocatalytic mechanism of the catalyst, there will be a certain degree of side reaction of two electrons, which will generate a certain amount of HO 2 - , its existence has a certain etching ability to carbon materials, which has a negative impact on the structure, life and electrochemical performance of the electrode;
[0015] 3) The electrochemical reaction process of the oxygen cathode is actually a gas-liquid-solid multi-phase catalytic reaction process, and the gas-liquid-solid three-phase reaction balance is difficult to control, which will affect the electrocatalytic efficiency of the oxygen cathode
[0016] 4) The mechanical strength of the oxygen cathode is low, the installation is difficult, and it is difficult to meet the needs of large-scale industrial production;
[0017] 5) The slurry dispersion process and film formation process of the oxygen cathode are complicated, and the drying requirements are high, so it is difficult to obtain an electrode with a good surface state and no cracks
[0018] At present, around the above difficulties, researchers from various countries have carried out a lot of work. Among them, in Japanese Patent Laid-Open No. 2007-327092, AB-6 carbon black is used as the hydrophobic carbon black, and AB-12 carbon black is used as the hydrophilic carbon black. , the gas diffusion electrode was prepared with silver powder as a catalyst, and a gas diffusion electrode with strong water pressure resistance and slow deterioration rate was obtained; Japanese Patent Laid-Open No. 2004-300451 used AB-6 carbon black as hydrophobic carbon black, and silver-plated The metal mesh is used as the catalyst layer. After the dispersion, filtration and drying steps of hydrophobic carbon black and binder, the silver-plated metal mesh is hot-pressed to prepare a gas diffusion electrode with stable performance, but the electrode is difficult Meet the requirements of industrial production of large electrodes; the patent CN101736360A discloses a gas diffusion electrode with a silver-plated nickel mesh as a support, and a silver-plated nickel mesh placed between the gas diffusion layer and the catalytic layer, but the electrode has its own mechanical The strength is weak, the surface of the electrode is prone to cracks during the production process, and it is difficult to demould during the hot pressing stage, and it is also difficult to meet the requirements of industrial production

Method used

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  • A gas diffusion electrode and its preparation method
  • A gas diffusion electrode and its preparation method
  • A gas diffusion electrode and its preparation method

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Embodiment 1

[0039] The carbon black with high graphitization degree used is obtained by graphitizing carbon black (Vulcan XC-72) in a high-temperature graphitization furnace at 2700°C for 6-10 h. The Raman spectrum for testing the degree of graphitization is as follows: figure 2 As shown, its Raman spectrum I D / I G 0.67, silver-plated nickel foam was prepared by electroplating, nickel foam was purchased from Heze Tianyu Technology Development Co., Ltd., acidified carbon black with high graphitization degree was prepared by heating graphitized carbon black in nitric acid (68% mass fraction) at 120°C ) solution was condensed and refluxed for 6-10 h.

[0040] 1) Weigh 0.4~2g high graphitization degree carbon black and disperse it in isopropanol aqueous solution containing 0.4~1g triton, in which isopropanol is 40mL, water is 10~25mL, and then the slurry solution is ultrasonically sheared After cutting for 60 minutes, add 1-2 g of polytetrafluoroethylene emulsion (D-110) with a mass fract...

Embodiment 2

[0045] The high graphitization degree carbon black used is obtained by graphitizing carbon black (Vulcan XC-72) at 2600°C for 2 to 15 hours, and its Raman spectrum I D / I G The silver-plated nickel foam is prepared by electroplating. The nickel foam is purchased from Heze Tianyu Science and Technology Development Co., Ltd. The acidified carbon black with high graphitization degree is obtained by heating graphitized carbon black at 140°C in nitric acid (mass fraction: 68%) obtained by condensing and refluxing in the solution for 6 to 10 hours.

[0046] 1) Weigh 1~3g high graphitization degree carbon black and disperse it in isopropanol aqueous solution containing 0.4~3g triton, in which isopropanol is 40mL, water is 4~16mL, and then the slurry solution is ultrasonically sheared After cutting for 60 minutes, add 0.4 to 1.5 g of polytetrafluoroethylene emulsion (D-110) with a mass fraction of 60%, and continue to shear and disperse for 10 minutes. After the dispersion is complet...

Embodiment 3

[0051] The high graphitization degree carbon black used is obtained by graphitizing carbon black (Vulcan XC-72) in a high temperature graphitization furnace at 2900°C for 2 to 15 hours, and its Raman spectrum I D / I G 0.3 to 0.6, silver-plated nickel foam is prepared by electroplating, and the nickel foam is purchased from Heze Tianyu Technology Development Co., Ltd. The acidified carbon black with high graphitization degree is prepared by heating graphitized carbon black at 160°C in nitric acid (mass fraction: 68%) obtained by condensing and refluxing the solution for 6-10 hours.

[0052] 1) Weigh 2-4g high graphitization degree carbon black and disperse it in isopropanol aqueous solution containing 2.5-4g triton, in which isopropanol is 40mL, water is 20-40mL, and then the slurry solution is ultrasonically sheared After cutting for 60 minutes, add 1.8 to 4 g of polytetrafluoroethylene emulsion (D-110) with a mass fraction of 60%, and continue to shear and disperse for 10 mi...

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Abstract

Provided are a gas diffusion electrode and a preparation method thereof. The gas diffusion electrode comprises a current collector 1, a gas diffusion layer 2, a gas catalysis layer 3 coated on the gas diffusion layer, and a liquid guide layer 4 located on the gas catalysis layer. The gas diffusion layer comprises highly-graphitized carbon black and polytetrafluoroethylene, and the gas catalysis layer comprises a catalyst, acidified highly-graphitized carbon black and polytetrafluoroethylene; the highly-graphitized carbon black has a peak intensity ratio I D / I G between 0.3 and 1.0 in the Raman spectrum, and the degrees of graphitization in the gas diffusion layer and the gas catalysis layer may be the same or different. The gas diffusion electrode has good corrosion resistance and excellent and stable electrochemical performance in alkali solutions, thus it is suitable for electrolytic reactions in the chlor-alkali industry.

Description

technical field [0001] The application belongs to the field of chemical industry, and in particular relates to a gas diffusion electrode suitable for chlor-alkali industry and a preparation method thereof. Background technique [0002] The chlor-alkali industry is a basic chemical industry that plays an important role in promoting the development of the national economy. At the same time, the chlor-alkali industry is a high-energy-consuming industry, and reducing the energy consumption of the chlor-alkali industry to the greatest extent has always been a subject of concern to all countries. [0003] In recent years, the ionic membrane salt electrolysis method, which replaces the hydrogen evolution cathode with the oxygen cathode, has gradually gained attention, and its essence is to replace the hydrogen evolution reaction with the oxygen reduction reaction. The reaction formula of the traditional ionic membrane alkali production method using the hydrogen evolution electrode...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25B11/08C25B11/03
CPCC25B1/46C25B11/031C25B11/043
Inventor 王峰曹寅亮刘景军李志林
Owner BEIJING UNIV OF CHEM TECH
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