A hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam self-supporting polyborate and its preparation method and application

Abstract

The present invention provides a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam-supported poly(phenylborate) and its preparation method and application. The preparation method of the bifunctional catalytic electrode comprises the following steps: 1) Pretreating nickel foam as a self-supporting substrate; 2) Electro-polymerizing the pretreated nickel foam in an electrolyte containing organic phenylboronic acid to form an organic phenylboronic acid polymer film on the surface of the carrier; 3) Immersing the nickel foam electro-deposited with the organic phenylboronic acid polymer film in a metal salt precursor solution, and forming nickel foam-supported poly(phenylborate) by adsorption self-assembly as the hydrogen evolution and oxygen evolution bifunctional catalytic electrode. The preparation method of forming nickel foam-supported poly(phenylborate) by adsorption self-assembly according to the present invention is applicable to self-supporting systems of various metal transition metal phenylborate polymers such as ruthenium borate, iron borate, cobalt borate, and nickel borate. The corresponding electrodes have excellent hydrogen evolution and oxygen evolution bifunctional electrocatalytic performance and stability under alkaline conditions. The hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam-supported poly(phenylborate) provided by the present invention has the advantages of simple and convenient preparation method, low cost, suitability for large-scale preparation, and excellent performance, and has broad application prospects in large-scale industrial water electrolysis.

Description

Technical Field

[0001] The present invention relates to the field of preparation and application of electrocatalytic electrodes, and particularly to the preparation of a self-supported hydrogen evolution and oxygen evolution bifunctional catalytic electrode on nickel foam and the application of this electrode in hydrogen evolution and oxygen evolution of water electrolysis, belonging to the field of electrocatalysis. Background Art

[0002] Water electrolysis for hydrogen production is considered a promising method to solve environmental problems and energy crises. Water electrolysis is a combination of two half-reactions: the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. However, these reactions do not occur spontaneously thermodynamically, and the theoretical potential required to initiate water electrolysis is 1.23 V. Due to energy losses during the energy conversion process, more additional potential than the theoretical value needs to be provided. To meet the requirements of industrial water electrolysis to reduce the overpotential and energy loss during the water electrolysis process, electrocatalytic electrodes are required to have characteristics such as high catalytic activity, high conductivity, high stability, etc., and are also beneficial to mass transfer during the hydrogen evolution and oxygen evolution processes and the release of non-disturbed gases.

[0003] Currently, the electrocatalytic electrodes applied to industrial water electrolysis mainly use the most advanced materials such as platinum, ruthenium / iridium and their oxides loaded as efficient electrocatalysts for hydrogen evolution or oxygen evolution. However, due to their insufficient global reserves, high cost, high overpotential at high current densities, and lack of stability, the large-scale industrial application of these precious materials has limitations. In recent years, people have vigorously developed various efficient hydrogen evolution and oxygen evolution electrocatalysts to replace the existing noble metal catalysts. However, most of the reported catalysts can only show certain catalytic activity and stability for HER or OER unidirectionally, which makes the structure of industrial integrated electrolyzers complex. To simplify the electrolyzer and reduce the overall cost of industrial applications, the development of a bifunctional electrocatalytic electrode that can catalyze both the HER process and the OER process is still the key to promoting large-scale industrial water electrolysis for hydrogen production and accelerating the rapid development of the hydrogen economy.

[0004] Recently, some studies have shown that transition metal borates (TM-Bi) have certain catalytic activity for both HER and OER.

[0005] Based on the above, the inventors of the present application have invented an electrocatalytic electrode with a simple preparation method but high efficiency in catalyzing the hydrogen evolution reaction and the oxygen evolution reaction, which can be used for industrial water electrolysis. Summary of the Invention

[0006] The present invention provides a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on self-supported polybenzeneborate on nickel foam, its preparation and application. The preparation method of this bifunctional catalytic electrode is simple, convenient, low-cost, suitable for large-scale preparation, has excellent electrocatalytic performance for hydrogen evolution and oxygen evolution, and has broad application prospects in large-scale industrial water electrolysis. The present invention is mainly realized by the following technical solutions:

[0007] A preparation method of a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam-supported polybenzeneborate, characterized by specifically comprising the following steps:

[0008] 1) Pretreatment of nickel foam: First, ultrasonically clean nickel foam in acetone solution, ethanol, and deionized water for 15 minutes respectively, and collect the obtained nickel foam for standby.

[0009] 2) Electro-deposition of organic benzeneboric acid polymer film: Dissolve the organic benzeneboric acid compound in an aqueous solution, fully stir to form a homogeneous aqueous solution of organic benzeneboric acid as the electrolyte for electro-polymerization. Use the treated nickel foam as the working electrode and the counter electrode respectively, and the saturated calomel electrode as the reference electrode. In-situ electro-deposit the organic benzeneboric acid polymer film PAB / NF on the nickel foam electrode by an electrochemical method. After electro-deposition, take out the nickel foam, rinse it with water, and dry it in vacuum for standby.

[0010] 3) Preparation of hydrogen evolution and oxygen evolution bifunctional catalytic electrode: Cut the nickel foam electro-deposited with the organic benzeneboric acid polymer film into an appropriate size, immerse it in an aqueous solution of a metal salt precursor with a concentration of 0.01% - 0.05%, and let it stand at room temperature for 6 - 24 h for adsorption self-assembly. Take out the nickel foam and rinse it repeatedly with deionized water, and dry it to obtain a hydrogen evolution and oxygen evolution bifunctional catalytic electrode PABM / NF (M is Ru, Fe, Co or Ni) based on nickel foam-supported polybenzeneborate. Preferably, in the step 2), the organic benzeneboric acid compound is 4-aminobenzeneboric acid or 3-aminobenzeneboric acid.

[0011] Preferably, in the step 2), the aqueous solution is 0.5 - 1 M H2SO4 or 0.5 - 1 M HNO3 or 0.5 - 1 M KOH aqueous solution.

[0012] Preferably, in the step 2), the concentration of the aqueous solution of the organic benzeneboric acid compound is 0.01 - 0.5 M.

[0013] Preferably, in the step 2), the electrochemical method uses cyclic voltammetry, the cyclic potential range is -0.2 - 0.8 V, and the number of cycles is 5 - 50.

[0014] Preferably, in the step 2), the electrochemical method uses constant current method, the current density is 0.05 - 5 mA cm -2 , and the polymerization time is 5 - 30 min.

[0015] Preferably, in the step 2), the electrochemical method uses constant potential method, the polarization potential is 0.2 - 0.8 V, and the polymerization time is 5 - 30 min.

[0016] Preferably, in the step 2), the electrochemical method uses pulsed current method, the current density is 0.05 - 5 mA cm-2 The power-on time and power-off time are 1:1, the frequency is 10 Hz, and the polymerization time is 5 - 30 min.

[0017] Preferably, in the step 3), the metal salt precursor aqueous solution is an aqueous solution of ruthenium chloride, nickel chloride, cobalt chloride, or iron chloride, or the corresponding sulfate or nitrate aqueous solution.

[0018] The present invention provides a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam self-supporting polymerized phenylborate prepared by the above preparation method.

[0019] The present invention provides an application of a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam self-supporting polymerized phenylborate in electrocatalytic hydrogen evolution, oxygen absorption, and water electrolysis. Compared with the prior art, the present invention has the following advantages:

[0020] The hydrogen evolution and oxygen evolution bifunctional catalytic electrode provided by the present invention is prepared by a simple method of electrodeposition and self-assembly. The process is simple and convenient, and suitable for large-scale production. At the same time, due to the high conductivity of nickel foam, the composite structure of a unique polymer thin film combined with a transition metal borate polymer nanostructure, the fast electron and mass transfer rates, and the promoting effect of the Lewis acid behavior exhibited by borate ions on the adsorption of oxygen-containing intermediates that exhibit Lewis base behavior similar to having lone pair electrons, the prepared PAB-M / NF self-supporting catalytic electrode exhibits excellent bifunctional catalytic activities for HER and OER, and has broad application prospects in the field of industrial water electrolysis.

[0021] Description of the drawings of the specification

[0022] Figure 1 Schematic diagram of the preparation process of the hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam self-supporting polymerized phenylborate of the present invention.

[0023] Figure 2 LSV polarization curve of hydrogen evolution and oxygen evolution of the hydrogen evolution and oxygen evolution bifunctional catalytic electrode PAB-M / NF based on nickel foam self-supporting polymerized phenylborate of the present invention in 1 M KOH.

[0024] Figure 3 Hydrogen evolution LSV polarization curve of the highly efficient hydrogen evolution and oxygen evolution bifunctional catalytic electrode with nickel foam self-supporting of the present invention before and after 1000 CV cycles in 1 M KOH solution.

[0025] Figure 4 Oxygen evolution LSV polarization curve of the highly efficient hydrogen evolution and oxygen evolution bifunctional catalyst with nickel foam self-supporting prepared by the present invention before and after 1000 CV cycles in 1 M KOH solution.

[0026] Figure 5Experimental curve of the stability test for the electrolysis of water using PAB-Ru / NF as both the cathode and the anode (1.0 M KOH solution, current density 10 mA cm -2 ). Specific implementation mode

[0027] The content of the present invention will be described in more detail with reference to the following examples, but this does not limit the scope of protection of the claims of the present invention.

[0028] Example 1

[0029] 1) Pretreatment of nickel foam: Nickel foam was ultrasonically cleaned in acetone solution, ethanol, and deionized water for 15 minutes respectively, and the obtained nickel foam was collected for later use.

[0030] 2) Electrodeposition of aminophenylboronic acid: The treated nickel foam with appropriate size (1×2 cm in this example 2 ) was used as the working electrode and the counter electrode, and the saturated calomel electrode was used as the reference electrode. 1.4 mL of concentrated sulfuric acid was dissolved in 48.6 mL of deionized water, and 4.0 g of aminophenylboronic acid was added and stirred for half an hour to form a homogeneous aqueous solution, obtaining the electrolyte solution. The current density was controlled at 3 mA cm -2 , and the in-situ electrodeposition was carried out on the nickel foam electrode for 15 min by the constant current method. Then, the nickel foam was taken out, rinsed with water, and dried in a vacuum drying oven at 60 °C.

[0031] 3) Preparation of PAB-Ru / NF: The nickel foam with electrodeposited aminophenylboronic acid was immersed in 50 ml of aqueous solution containing 10 mg of ruthenium chloride, and left standing at room temperature for 8 h for adsorption self-assembly. The nickel foam was taken out, repeatedly rinsed with deionized water, and then dried, finally obtaining the nickel foam self-supported polymer borate ruthenium electrode, denoted as PAB-Ru / NF.

[0032] Example 2

[0033] 1) Pretreatment of nickel foam: Nickel foam was ultrasonically cleaned in acetone solution, ethanol, and deionized water for 15 minutes respectively, and the obtained nickel foam was collected for later use.

[0034] 2) Electrodeposition of aminophenylboronic acid: The treated nickel foam with appropriate size (1×2 cm in this example 2 ) was used as the working electrode and the counter electrode, and the saturated calomel electrode was used as the reference electrode. 1.8 mL of concentrated sulfuric acid was dissolved in 48.2 mL of deionized water, and 2.7 g of aminophenylboronic acid was added and stirred for half an hour to form a homogeneous aqueous solution, obtaining the electrolyte solution. The current density was controlled at 2 mA cm -2 , and the in-situ electrodeposition was carried out on the nickel foam electrode for 15 min by the constant current method. Then, the nickel foam was taken out, rinsed with water, and dried in a vacuum drying oven at 60 °C.

[0035] 3) Preparation of PAB-Ni / NF: The nickel foam electro-deposited with aminophenylboronic acid was immersed in 50 ml of aqueous solution containing 20 mg of nickel chloride, and left standing for 8 h at room temperature for adsorption self-assembly. Then the nickel foam was taken out and repeatedly rinsed with deionized water, and then dried. Finally, a nickel foam self-supporting polymer nickel borate electrode was obtained, denoted as PAB-Ni / NF.

[0036] Example 3

[0037] 1) Pretreatment of nickel foam: The nickel foam was ultrasonically cleaned in acetone solution, ethanol and deionized water for 15 minutes respectively, and the obtained nickel foam was collected for standby.

[0038] 2) Electro-deposition of aminophenylboronic acid: The treated nickel foam with appropriate size (1×2 cm in this example 2 ) was used as the working electrode and the counter electrode, and the saturated calomel electrode was used as the reference electrode. 3.0 g of aminophenylboronic acid was added to 50 mL of 1 M KOH, and after stirring for half an hour, a uniform aqueous solution was formed to prepare the electrolyte. Cyclic voltammetry was used, and the cyclic potential range was -0.2 to 0.8 V, with 10 cycles. Then, the nickel foam was taken out, rinsed with water, and dried in a vacuum drying oven at 60 °C.

[0039] 3) Preparation of PAB-Co / NF: The nickel foam electro-deposited with aminophenylboronic acid was immersed in 50 ml of aqueous solution containing 20 mg of cobalt nitrate, and left standing for 12 h at room temperature for adsorption self-assembly. Then the nickel foam was taken out and repeatedly rinsed with deionized water, and then dried. Finally, a nickel foam self-supporting polymer cobalt borate electrode was obtained, denoted as PAB-Co / NF.

[0040] Example 4

[0041] 1) Pretreatment of nickel foam: The nickel foam was ultrasonically cleaned in acetone solution, ethanol and deionized water for 15 minutes respectively, and the obtained nickel foam was collected for standby.

[0042] 2) Electro-deposition of aminophenylboronic acid: The treated nickel foam with appropriate size (1×2 cm in this example 2 ) was used as the working electrode and the counter electrode, and the saturated calomel electrode was used as the reference electrode. 3.0 g of aminophenylboronic acid was added to 50 mL of 0.5 M HNO3, and after stirring for half an hour, a uniform aqueous solution was formed to prepare the electrolyte. Pulse current method was used, the current density was 3 mA cm -2 , the on-time and off-time were 1:1, the frequency was 10 Hz, and the polymerization time was 25 min. Then, the nickel foam was taken out, rinsed with water, and dried in a vacuum drying oven at 60 °C.

[0043] 3) Preparation of PAB-Fe / NF: The nickel foam electro-deposited with aminophenylboronic acid was immersed in 50 ml of aqueous solution containing 15 mg of iron nitrate, and left standing for 24 h at room temperature for adsorption self-assembly. Then the nickel foam was taken out and repeatedly rinsed with deionized water, and then dried. Finally, the self-supporting polymer iron borate electrode of nickel foam was obtained, denoted as PAB-Fe / NF.

[0044] Comparative example

[0045] The pretreated nickel foam was electro-deposited with aminophenylboronic acid by referring to the same steps and conditions of nickel foam pretreatment and aminophenylboronic acid electro-deposition in Example 1, and labeled as PAB / NF.

[0046] The hydrogen evolution and oxygen evolution catalytic performances of the electrode materials in Examples 1-4 and the comparative example were evaluated at room temperature by a CHI 660D electrochemical test system (Shanghai Chenhua). A graphite rod and a saturated calomel electrode (SCE) were used as the auxiliary electrode and the reference electrode respectively, and the prepared self-supporting nickel foam electrode was used as the working electrode. The prepared samples were directly used as the working electrode without any treatment. The contact area between the working electrode and the electrolyte was 1 cm 2 . The test electrolyte was 1 M KOH aqueous solution. The scanning rate of linear sweep voltammetry (LSV) was 2 mV / s. The potentials of all measured electrocatalysts were converted to the overpotential relative to the reversible hydrogen electrode (RHE): E(RHE) = E(SCE) + (0.059 × pH) + 0.241. All LSV curves were not corrected for iR.

[0047] Figure 2 a is the LSV polarization curve of the self-supporting nickel foam electrode prepared in Examples 1-4 and the comparative example for hydrogen evolution in 1 M KOH. Figure 2 b is the LSV polarization curve of the self-supporting nickel foam electrode prepared in Examples 1-4 and the comparative example for oxygen evolution in 1 M KOH. As Figure 2 a and Figure 2 b show, the self-supporting electrodes of metal transition metal borate polymers formed by adsorption self-assembly based on polyaminophenylboronic acid all have good hydrogen evolution and oxygen evolution catalytic activities. In the 1 M KOH solution, the hydrogen evolution overpotentials η 10 of the PAB-Ru / NF, PAB-Ni / NF, PAB-Co / NF, and PAB-Fe / NF electrodes prepared in Examples 1-4 are 24, 161, 209, and 98 mV respectively, and the oxygen evolution overpotentials η 10 are 204, 302 (20 mA cm -2 )), 274, and 244 mV respectively. Among the prepared catalytic electrodes, PAB-Ru / NF has the best hydrogen evolution and oxygen evolution catalytic performance, and its performance is even better than that of most reported bifunctional hydrogen evolution and oxygen evolution catalytic materials.

[0048] Meanwhile, 1000 CV cycles were performed at a scan rate of 10 mV s -1 in 1 M KOH solution, and the LSV polarization curves before and after the cycles were measured and compared to evaluate the stability of the electrode. Figure 3 Hydrogen evolution LSV polarization curves of PAB-Ru / NF (a), PAB-Ni / NF (b), PAB-Co / NF (c) and PAB-Fe / NF (d) prepared in Examples 1-4 before and after 1000 CV cycles in 1 M KOH solution. Figure 4 Oxygen evolution LSV polarization curves of PAB-Ru / NF (a), PAB-Ni / NF (b), PAB-Co / NF (c) and PAB-Fe / NF (d) prepared in Examples 1-4 before and after 1000 CV cycles in 1 M KOH solution. Figure 3 and Figure 4 The test results show that the self-supported high-efficiency hydrogen and oxygen evolution bifunctional catalytic electrode made of nickel foam proposed in the present invention has excellent stability during hydrogen and oxygen evolution catalysis in 1 M KOH solution.

[0049] The overall hydrolysis performance of PAB-Ru / NF prepared in Test Example 1 was tested to investigate its potential industrial application. At room temperature (25 °C), PAB-Ru / NF was used as both the cathode and the anode for overall hydrolysis in an electrolytic cell with 1 M KOH. The test shows that PAB-Ru / NF exhibits excellent overall hydrolysis performance and can drive a current density of 10 mA cm -2 at a low cell voltage of 1.519 V. Figure 5 The long-term stability test experimental curve of the PAB-Ru / NF / / PAB-Ru / NF electrolytic device at a current density of 10 mA cm -2 . As Figure 5 shown, during continuous operation of up to 72000 s, the current density shown by the PAB-Ru / NF / / PAB-Ru / NF electrolytic device hardly decays, showing stable long-term durability, indicating that the polymer film / transition metal borate polymer composite catalytic electrode prepared by the strategy of electrodeposition and electrostatic self-assembly proposed in the present invention has very excellent durability and good industrial application prospects.

Claims

1. A preparation method of a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam self-supporting polyborate, characterized in that, Specifically, it includes the following steps: 1) Pretreatment of nickel foam: First, ultrasonically clean nickel foam in acetone solution, ethanol, and deionized water for 15 minutes respectively, and collect the obtained nickel foam for standby; 2) Electro-deposition of organic phenylboronic acid polymer film: Dissolve the organic phenylboronic acid compound in an aqueous solution, stir well to form a homogeneous aqueous solution of organic phenylboronic acid as the electrolyte for electro-polymerization; Use the treated nickel foam as the working electrode and the counter electrode respectively, and the saturated calomel electrode as the reference electrode; Adopt an electrochemical method to in-situ electro-deposit an organic phenylboronic acid polymer film PAB / NF on the nickel foam electrode; After electro-deposition, take out the nickel foam, rinse it with water, and dry it in vacuum for standby; 3) Preparation of hydrogen evolution and oxygen evolution bifunctional catalytic electrode: Cut the nickel foam electro-deposited with the organic phenylboronic acid polymer film into appropriate sizes, immerse it in an aqueous solution of metal salt precursor with a concentration of 0.01% - 0.05%, and let it stand at room temperature for 6 - 24 h for adsorption self-assembly. Take out the nickel foam and rinse it repeatedly with deionized water, and obtain a hydrogen evolution and oxygen evolution bifunctional catalytic electrode PAB-M / NF based on self-supporting polymerized phenylborate on nickel foam after drying, where M is Ru, Fe, Co, or Ni.

2. The preparation method of the bifunctional catalytic electrode according to claim 1, wherein: In step 2), the organic phenylboronic acid compound is 4-aminophenylboronic acid or 3-aminophenylboronic acid.

3. The preparation method of the bifunctional catalytic electrode according to claim 1, wherein: In step 2), the aqueous solution is 0.5 - 1M H2SO4 or 0.5 - 1M HNO3 or 1M KOH aqueous solution.

4. The preparation method of the bifunctional catalytic electrode according to claim 1, characterized in that: In step 2), the concentration of the homogeneous aqueous solution of organic phenylboronic acid is 0.01 - 0.5M.

5. The preparation method of the bifunctional catalytic electrode according to claim 1, characterized in that: In step 2), the electrochemical method uses cyclic voltammetry, the cyclic potential range is -0.2 - 0.8V, and the number of cycles is 5 - 50.

6. The preparation method of the bifunctional catalytic electrode according to claim 1, characterized in that: In the step 2), the electrochemical method adopts the constant current method, and the current density is 0.05 - 5 mA·cm -2 , and the electro-deposition time is 5 - 30 min.

7. The preparation method of the bifunctional catalytic electrode according to claim 1, wherein: In step 2), the electrochemical method uses potentiostatic method, the polarization potential is 0.2 - 0.8V, and the electro-deposition time is 5 - 30 min.

8. The preparation method of the bifunctional catalytic electrode according to claim 1, characterized in that: In step 2), the electrochemical method uses the pulsed current method, and the current density is 1-5 mA·cm -2 , the on-time and off-time of the current are 1:1, the frequency is 10 Hz, and the electrodeposition time is 5-30 min.

9. The preparation method of the bifunctional catalytic electrode according to claim 1, characterized in that: In step 3), the aqueous solution of metal salt precursor is ruthenium chloride, nickel chloride, cobalt chloride, or iron chloride or their corresponding sulfate and nitrate aqueous solutions.

10. A bifunctional catalytic electrode prepared by the preparation method of a hydrogen evolution and oxygen evolution bifunctional catalytic electrode based on nickel foam self-supporting polyborate as described in any one of claims 1 to 9, characterized in that The bifunctional catalytic electrode has excellent HER and OER electrocatalytic performance and stability, and can be used as a hydrogen evolution and oxygen evolution catalytic electrode for industrial water electrolyzers.

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