A platinum-nickel catalyst gas diffusion electrode and its preparation method and application

Abstract

The present invention provides a platinum-nickel catalyst gas diffusion electrode, its preparation method and application, belonging to the technical field of electrode materials. First, a conductive material and a polymer are dispersed in ethanol to obtain a dispersion liquid, and then the dispersion liquid is coated on a Ni mesh and subjected to calcination treatment to obtain a gas diffusion layer electrode. Then, the gas diffusion layer electrode is placed in an electrolyte for electrodeposition, and then calcination treatment is carried out to obtain the platinum-nickel catalyst gas diffusion electrode. The platinum-nickel catalyst gas diffusion electrode prepared by the present invention effectively solves the problem of slow kinetics of the 2e- electrochemical oxygen reduction reaction under neutral conditions, reduces the usage amount of noble metals, increases the production of hydrogen peroxide, shows high catalytic activity and stability, and can also remove harmful substances such as malachite green in water bodies.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode materials, and in particular, to a platinum-nickel catalyst gas diffusion electrode, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen peroxide (H2O2) is one of the most important and fundamental chemicals, and it is widely used in different industries, including paper and pulp manufacturing, disinfection, wastewater treatment, and chemical synthesis. However, the current industrial method for large-scale production of H2O2 is the anthraquinone cycle process. This traditional method consumes a large amount of H2 and other types of energy, generates a large amount of organic waste, and requires a complex separation process to obtain high-purity H2O2 for use. In addition, the anthraquinone cycle process requires centralized large-scale infrastructure to be realized, which requires the transportation and storage of high-concentration H2O2, and the risk factor is very high. To overcome this limitation, it is urgent to find alternative strategies for synthesizing H2O2 to reduce energy consumption, waste, production costs, and safety issues.

[0003] Electrochemical oxygen reduction reaction (ORR) electrochemically synthesizes H2O2 through a 2e - transfer process. Compared with the traditional anthraquinone process, it can be realized under mild reaction conditions using green reaction precursors (such as air and water), which has attracted extensive attention from researchers. During the process of electrochemically synthesizing H2O2 by the oxygen reduction reaction, the selectivity of the catalyst, the mass transfer of oxygen, and the electron transfer at the cathode reaction interface are three important factors for realizing the efficient production of H2O2. Unfortunately, at normal temperature and pressure, the solubility of oxygen in water is as low as 8 mg / L, ORR is controlled by oxygen mass transfer, and the electrode overflow problem leads to slow 2e - ORR reaction kinetics. Therefore, it is of great significance to develop a platinum-nickel catalyst gas diffusion electrode to improve the electro-synthesis efficiency of H2O2. Summary of the Invention

[0004] The purpose of the present invention is to provide a platinum-nickel catalyst gas diffusion electrode, a preparation method thereof, and an application thereof to solve the technical problem of low electro-synthesis efficiency of H2O2 in the prior art.

[0005] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a preparation method of a platinum-nickel catalyst gas diffusion electrode, including the following steps:

[0007] Placing the gas diffusion layer electrode in an electrolyte for electrodeposition, and then performing a calcination treatment to obtain the platinum-nickel catalyst gas diffusion electrode;

[0008] The preparation method of the gas diffusion layer electrode includes the following steps:

[0009] (1)Disperse the conductive material and the polymer in ethanol to obtain a dispersion liquid;

[0010] (2)Coat the dispersion liquid on a Ni mesh, and then perform a calcination treatment to obtain a gas diffusion layer electrode.

[0011] Further, in the step (1), the conductive material includes one or more of acetylene black, graphene, graphite powder, carbon nanotubes, and MXenes; the polymer is perfluorosulfonic acid or polytetrafluoroethylene.

[0012] Further, the mass ratio of the conductive material to the polymer is 2 - 10:1 - 5; the solid-liquid ratio of the polymer to ethanol is 1 - 5 g:10 - 100 mL.

[0013] Further, in the step (2), the temperature of the calcination treatment is 300 - 500 °C, and the time of the calcination treatment is 20 - 180 min.

[0014] Further, the electrolyte is prepared by mixing potassium chloroplatinate and nickel salt in ethylene glycol, wherein the molar ratio of potassium chloroplatinate to nickel salt is 1 - 3:1 - 10; the molar volume ratio of potassium chloroplatinate to ethylene glycol is 1 - 3 mmol:800 - 1200 mL; the nickel salt includes one or more of nickel sulfate, nickel nitrate, nickel acetate, nickel acetylacetonate, and nickel chloride.

[0015] Further, the voltage range of the electrodeposition is -1.5 - 1.2 V, the scanning rate is 10 - 200 mV / s, and the number of scanning cycles is 100 - 500 cycles.

[0016] Further, after the electrodeposition, the calcination treatment is carried out under a gas atmosphere condition, and the gas atmosphere includes one or more of hydrogen, nitrogen, and argon.

[0017] Further, the temperature of the calcination treatment is 650 °C - 950 °C, and the time of the calcination treatment is 20 - 120 min.

[0018] The present invention provides a platinum-nickel catalyst gas diffusion electrode.

[0019] The present invention provides an application of the platinum-nickel catalyst gas diffusion electrode in improving the H2O2 production rate and removing malachite green in water bodies.

[0020] The beneficial effects of the present invention:

[0021] (1) The gas diffusion electrode of the platinum-nickel catalyst prepared by the present invention first grafts polytetrafluoroethylene (PTFE) onto the conductive material through calcination treatment to form a three-dimensional cross-linked porous structure, and uses the good hydrophobic effect of PTFE to coat a hydrophobic and breathable layer on the surface of the Ni mesh. Then, using the good electrochemical properties of Pt-Ni, it is loaded on the surface by electrodeposition. After calcination, the electrode forms a gas-liquid-solid three-phase reaction interface in the electrolyte, providing sufficient channels to accelerate the gas transmission rate, thereby improving the reactivity and stability of the reaction.

[0022] (2) In the gas diffusion electrode of the platinum-nickel catalyst prepared by the present invention, the loading amount of Pt-Ni is 2-10 mg / cm 2 , effectively solving the problem of slow kinetics of the 2e - electrochemical oxygen reduction reaction under neutral conditions, reducing the usage amount of precious metals, increasing the production of hydrogen peroxide, and showing high catalytic activity and stability.

[0023] (3) The gas diffusion electrode of the platinum-nickel catalyst prepared by the present invention realizes the removal of harmful substances such as malachite green in water. The decolorization rate of malachite green can reach 91.39% at 10 minutes, thus achieving the effect of on-line generating H2O2 and reducing water pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a relationship curve graph of the concentration and time of generating H2O2 by the gas diffusion electrode of the platinum-nickel catalyst prepared in Example 1 under neutral conditions;

[0025] Figure 2 It is a relationship curve graph of the absorbance and time of malachite green in water by the gas diffusion electrode of the platinum-nickel catalyst prepared in Example 1 under neutral conditions. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention provides a preparation method of a gas diffusion electrode of a platinum-nickel catalyst, including the following steps:

[0027] Place the gas diffusion layer electrode in the electrolyte for electrodeposition, and then perform calcination treatment to obtain the gas diffusion electrode of the platinum-nickel catalyst;

[0028] The preparation method of the gas diffusion layer electrode includes the following steps:

[0029] (1) Disperse the conductive material and the polymer in ethanol to obtain a dispersion;

[0030] (2) Coat the dispersion on the Ni mesh, and then perform calcination treatment to obtain the gas diffusion layer electrode.

[0031] In the present invention, the Ni mesh preferably uses a Ni mesh with a mesh number of 10 to 100 meshes, and before use, it is preferably ultrasonically decontaminated with acetone, ethanol, and deionized water.

[0032] In the present invention, in the step (1), the conductive material includes one or more of acetylene black, graphene, graphite powder, carbon nanotubes, and MXenes, preferably one or more of acetylene black, graphene, graphite powder, and carbon nanotubes, and further preferably one or more of acetylene black, graphene, and graphite powder; the polymer is perfluorosulfonic acid or polytetrafluoroethylene, preferably polytetrafluoroethylene.

[0033] In the present invention, the mass ratio of the conductive material to the polymer is 2 to 10:1 to 5, preferably 3 to 8:3, and further preferably 4 to 7:3; the solid-liquid ratio of the polymer to ethanol is 1 to 5 g:10 to 100 mL, preferably 3 g:20 to 80 mL, and further preferably 3 g:50 mL.

[0034] In the present invention, in the step (1), dispersing the conductive material and the polymer in ethanol is preferably carried out at 60 to 80 °C, and further preferably at 70 °C.

[0035] In the present invention, it is preferred to coat the dispersion on the Ni mesh by brushing or rolling, and the coating thickness of the dispersion is 0.01 to 3 mm, preferably 1 to 2 mm, and further preferably 2 mm.

[0036] In the present invention, in the step (2), the temperature of the calcination treatment is 300 to 500 °C, preferably 350 to 450 °C, and further preferably 350 °C; the time of the calcination treatment is 20 to 180 min, preferably 50 to 150 min, and further preferably 60 to 120 min.

[0037] In the present invention, the electrolyte is prepared by mixing potassium chloroplatinate and nickel salt in ethylene glycol, wherein the molar ratio of potassium chloroplatinate to nickel salt is 1 to 3:1 to 10, preferably 2:5 to 8, and further preferably 2:6; the molar volume ratio of potassium chloroplatinate to ethylene glycol is 1 to 3 mmol:800 to 1200 mL, preferably 2 mmol:900 to 1100 mL, and further preferably 2 mmol:1000 mL; the nickel salt includes one or more of nickel sulfate, nickel nitrate, nickel acetate, nickel acetylacetonate, and nickel chloride, preferably one or more of nickel sulfate, nickel nitrate, nickel acetate, and nickel acetylacetonate, and further preferably one or more of nickel sulfate, nickel nitrate, and nickel acetate.

[0038] In the present invention, the voltage range for electrodeposition is -1.5 to 1.2 V, preferably -1.5 to 1.0 V, and more preferably -1.0 to 0.5 V; the scanning rate is 10 to 200 mV / s, preferably 50 to 150 mV / s, and more preferably 50 mV / s; the number of scanning cycles is 100 to 500 cycles, preferably 200 to 400 cycles, and more preferably 300 cycles.

[0039] In the present invention, after electrodeposition, the calcination treatment is carried out under a gas atmosphere condition, and the gas atmosphere includes one or more of hydrogen, nitrogen, and argon, preferably a hydrogen / argon mixture, nitrogen, or argon, and more preferably nitrogen or argon.

[0040] In the present invention, the temperature of the calcination treatment is 650 °C to 950 °C, preferably 700 °C to 900 °C, and more preferably 750 °C to 850 °C; the time of the calcination treatment is 20 to 120 min, preferably 40 to 100 min, and more preferably 60 to 80 min.

[0041] The present invention provides a platinum-nickel catalyst gas diffusion electrode.

[0042] In the present invention, the loading amount of Pt-Ni in the platinum-nickel catalyst gas diffusion electrode is 2 to 10 mg / cm 2 .

[0043] The present invention provides an application of a platinum-nickel catalyst gas diffusion electrode in improving the H2O2 production rate and removing malachite green in water.

[0044] The technical solutions provided by the present invention are described in detail below with reference to the examples, but they should not be construed as limiting the protection scope of the present invention.

[0045] Example 1

[0046] 1 g of acetylene black and 0.6 g of polytetrafluoroethylene were dispersed in 10 mL of ethanol, heated to 70 °C to obtain a uniform dispersion, and then the dispersion was brushed onto a Ni mesh with a mesh number of 50, the brushing thickness was 2 mm, and after drying, it was placed in a muffle furnace and calcined at 350 °C for 120 min to prepare a gas diffusion layer electrode.

[0047] Using the gas diffusion layer electrode as the working electrode, place it in the electrolyte solution, which is prepared by mixing 0.2 mmol of potassium chloroplatinate and 0.6 mmol of nickel sulfate in 100 mL of ethylene glycol. Use an electrochemical workstation for cyclic voltammetry electrodeposition. Set the voltage range to -1.0 V to 0.5 V, the scanning rate to 50 mV / s, and the number of scanning cycles to 300. After the electrodeposition is completed, perform a calcination treatment on the electrode in a nitrogen atmosphere. The calcination temperature is 850 °C and the calcination time is 60 min, then the platinum-nickel catalyst gas diffusion electrode can be obtained. The Pt-Ni loading amount in the platinum-nickel catalyst gas diffusion electrode prepared in Example 1 is 4 mg / cm 2 。

[0048] Example 2

[0049] Disperse 1 g of acetylene black and 0.1 g of polytetrafluoroethylene in 20 mL of ethanol, heat to 80 °C to obtain a uniform dispersion, then brush the dispersion onto a Ni mesh with a mesh size of 10, and the brushing thickness is 1 mm. After drying, place it in a muffle furnace and calcine at 350 °C for 60 min to prepare the gas diffusion layer electrode.

[0050] Using the gas diffusion layer electrode as the working electrode, place it in the electrolyte solution, which is prepared by mixing 0.2 mmol of potassium chloroplatinate and 0.1 mmol of nickel nitrate in 120 mL of ethylene glycol. Use an electrochemical workstation for cyclic voltammetry electrodeposition. Set the voltage range to -1.0 V to 0.5 V, the scanning rate to 200 mV / s, and the number of scanning cycles to 100. After the electrodeposition is completed, perform a calcination treatment on the electrode in an argon atmosphere. The calcination temperature is 950 °C and the calcination time is 30 min, then the platinum-nickel catalyst gas diffusion electrode can be obtained. The Pt-Ni loading amount in the platinum-nickel catalyst gas diffusion electrode prepared in Example 2 is 2 mg / cm 2 。

[0051] Example 3

[0052] Disperse 0.7 g of acetylene black and 0.2 g of polytetrafluoroethylene in 50 mL of ethanol, heat to 60 °C to obtain a uniform dispersion, then brush the dispersion onto a Ni mesh with a mesh size of 100, and the brushing thickness is 3 mm. After drying, place it in a muffle furnace and calcine at 300 °C for 80 min to prepare the gas diffusion layer electrode.

[0053] Using the gas diffusion layer electrode as the working electrode, it was placed in the electrolyte solution, which was prepared by mixing 0.2 mmol of potassium chloroplatinate and 1 mmol of nickel acetylacetonate in 80 mL of ethylene glycol. A cyclic voltammetry electrodeposition was carried out using an electrochemical workstation. The voltage range was set from -1.5 V to 1.0 V, the scanning rate was 100 mV / s, and the number of scanning cycles was 500. After the electrodeposition, the electrode was calcined in a hydrogen / argon mixed gas atmosphere. The calcination temperature was 650 °C and the calcination time was 60 min, thus obtaining the platinum-nickel catalyst gas diffusion electrode. The Pt-Ni loading in the platinum-nickel catalyst gas diffusion electrode prepared in Example 3 was 10 mg / cm 2 .

[0054] Performance verification

[0055] Using the platinum-nickel catalyst gas diffusion electrode prepared in Example 1 as the cathode and a Pt sheet as the anode, under the working of a 10 V DC power supply, the content of H2O2 was detected, and at the same time, malachite green in the water body could be removed.

[0056] Figure 1 It is a relationship curve graph of the concentration and time of H2O2 generated by the platinum-nickel catalyst gas diffusion electrode prepared in Example 1. From Figure 1 it can be obtained that when using the platinum-nickel catalyst gas diffusion electrode prepared in Example 1, the concentration of H2O2 generated increases with time, and 42 mg / L of H2O2 can be generated in 20 min.

[0057] Figure 2 It is a relationship curve graph of the absorbance and time of malachite green in the water body by the platinum-nickel catalyst gas diffusion electrode prepared in Example 1 under neutral conditions. From Figure 2 it can be obtained that when using the platinum-nickel catalyst gas diffusion electrode prepared in Example 1, the absorbance of malachite green increases with time, and the decolorization rate of malachite reaches 91.39% at 10 min.

[0058] From the above examples, it can be seen that the present invention provides a platinum-nickel catalyst gas diffusion electrode, its preparation method and application. First, the conductive material and the polymer are dispersed in ethanol to obtain a dispersion liquid, and then the dispersion liquid is coated on the Ni mesh and calcined to obtain the gas diffusion layer electrode. Then, the gas diffusion layer electrode is placed in the electrolyte solution for electrodeposition, and then calcined, thus obtaining the platinum-nickel catalyst gas diffusion electrode. The platinum-nickel catalyst gas diffusion electrode prepared by the present invention effectively solves the problem of slow kinetics of the 2e - electrochemical oxygen reduction reaction under neutral conditions, and reduces the usage amount of precious metals, increases the production of hydrogen peroxide, shows high catalytic activity and stability, and can also remove harmful substances such as malachite green in the water body.

[0059] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a platinum-nickel catalyst gas diffusion electrode, characterized in that, It includes the following steps: Place the gas diffusion layer electrode in the electrolyte for electrodeposition, and then perform calcination treatment to obtain the platinum-nickel catalyst gas diffusion electrode; The preparation method of the gas diffusion layer electrode includes the following steps: (1) Disperse the conductive material and the polymer in ethanol to obtain a dispersion; (2) Coat the dispersion on the Ni mesh, and then perform calcination treatment to obtain the gas diffusion layer electrode; The electrolyte is prepared by mixing potassium chloroplatinate and nickel salt in ethylene glycol, where the molar ratio of potassium chloroplatinate to nickel salt is 1-3:1-10; the molar volume ratio of potassium chloroplatinate to ethylene glycol is 1-3 mmol: 800-1200 mL; The voltage range of the electrodeposition is -1.5 to 1.2 V, the scanning rate is 10 to 200 mV / s, and the number of scanning cycles is 100 to 500 cycles; After electrodeposition, the temperature of the calcination treatment is 650°C to 950°C, and the time of the calcination treatment is 20 to 120 min.

2. The preparation method of a platinum-nickel catalyst gas diffusion electrode according to claim 1, characterized in that, In the step (1), the conductive material includes one or more of acetylene black, graphene, graphite powder, carbon nanotubes, and MXenes; the polymer is perfluorosulfonic acid or polytetrafluoroethylene.

3. The preparation method of a platinum-nickel catalyst gas diffusion electrode according to claim 2, characterized in that, The mass ratio of the conductive material to the polymer is 2-10:1-5; the solid-liquid ratio of the polymer to ethanol is 1-5 g:10-100 mL.

4. The preparation method of a platinum-nickel catalyst gas diffusion electrode according to claim 2 or 3, characterized in that, In the step (2), the temperature of the calcination treatment is 300 to 500°C, and the time of the calcination treatment is 20 to 180 min.

5. A method for preparing a platinum-nickel catalyst gas diffusion electrode according to any one of claims 1 to 3, characterized in that, The nickel salt includes one or more of nickel sulfate, nickel nitrate, nickel acetate, nickel acetylacetonate, and nickel chloride.

6. The preparation method of a platinum-nickel catalyst gas diffusion electrode according to claim 1 or 2 or 3, characterized in that, After electrodeposition, the calcination treatment is carried out under a gas atmosphere condition, and the gas atmosphere includes one or more of hydrogen, nitrogen, and argon.

7. The platinum-nickel catalyst gas diffusion electrode prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the platinum-nickel catalyst gas diffusion electrode according to claim 7 in improving the H2O2 yield and removing malachite green in water bodies.

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