ZnCo (OH) F-S / NF electrocatalytic hydrogen evolution electrode and preparation method thereof
By growing cobalt hydroxide on foam nickel and doping ZnCo(OH)F-S/NF catalytic electrodes with Zn cations and F and S anions, the problem of low catalytic activity of electrolytic hydrogen production catalyst in alkaline electrolyte is solved, and the catalytic activity of electrolytic water hydrogen production catalyst is achieved. The efficient catalytic performance of cobalt hydroxide reduces production energy consumption.
Patent Information
- Application Number
- CN202411556471.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-04
- Publication Date
- 2025-01-03
Smart Images
Figure CN119243245A_ABST
Abstract
Description
Technical Field
[0001] The invention discloses a method for preparing an anion-cation co-doped fluorinated hydroxycobalt electrocatalytic hydrogen evolution catalytic electrode, which belongs to the field of energy conversion. Background Art
[0002] The massive consumption of traditional fossil fuels has led to the continuous aggravation of environmental problems, so people are in urgent need of finding sustainable clean energy. Hydrogen energy has the characteristics of high energy density and environmental friendliness, and is considered to be an important part of the future energy structure. Among the many methods for obtaining hydrogen energy, water electrolysis hydrogen production technology has received widespread attention. This method is simple to operate and environmentally friendly, so electrocatalytic hydrogen evolution is considered to be a technology with great application prospects. Precious metals such as platinum (Pt) and ruthenium (Ru) and their compounds have high theoretical activity, but due to low reserves and high prices, the development of large-scale economic hydrogen production is seriously hindered. Therefore, the development of high catalytic activity, low price and stable catalysts is a hot topic in the field of water electrolysis hydrogen production today. At present, most of the reports on non-precious metal hydrogen evolution catalysts in existing domestic and foreign invention patents use sulfides, selenides, carbides, nitrides, phosphides, etc. of iron, cobalt, nickel, molybdenum, and tungsten. These catalysts generally have good catalytic activity in acidic electrolytes, but poor performance in alkaline electrolytes. Generally reach 10mA / cm 2 The overpotential required for the current density is more than 100mV; the Tafel slope is more than 90mV / dec, which greatly increases the production energy consumption. Summary of the invention
[0003] In order to solve the above problems, the present invention provides a method for preparing a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode. The electrode is prepared by a method combining hydrothermal reaction and room temperature liquid impregnation.
[0004] A method for preparing a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode is carried out according to the following steps:
[0005] 1. Dissolve ammonium fluoride and urea in water respectively to prepare a 0.01 mol / L ammonium fluoride solution and a 0.012 mol / L urea solution, and mix the two solutions to obtain a solution A;
[0006] 2. Add cobalt nitrate hexahydrate and zinc nitrate hexahydrate into solution A and stir evenly to form solution B. The total concentration of cobalt nitrate and zinc nitrate in the obtained solution B is 0.075 mol / L. ;
[0007] 3. Transfer the mixed solution B to the reactor, add a piece of nickel foam, seal it and perform hydrothermal reaction at a temperature of 90-120°C for 5-10h to obtain ZnCo(OH)F / NF;
[0008] Fourth, sodium sulfide nonahydrate is dissolved in water to prepare a sodium sulfide solution with a concentration of 0.1 mol / L, and the ZnCo(OH)F / NF obtained in the third step is immersed in the sodium sulfide solution at room temperature for 0.5 to 3 hours, and then taken out, washed and dried to obtain a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode.
[0009] Compared with the existing technology, the invention has the following beneficial effects: the preparation method is simple, highly repeatable, and suitable for popularization and application; different from the chemical composition of the catalyst reported in the past, the obtained catalytic electrode uses cobalt hydroxide as the main component, is doped with Zn cations and F and S anions, and is directly grown on nickel foam for catalytic hydrogen evolution electrode; the catalytic hydrogen evolution electrode has excellent catalytic performance in alkaline electrolyte, reaching 10 mA / cm 2 The overpotential required for the catalytic current density is 55mV, and the Tafel slope is 56.9mV / dec, which is comparable to the currently commonly used precious metal platinum catalyst (37mV, 52.3mV / dec), and is superior to most of the reported non-precious metal hydrogen evolution catalysts. It also solves the problem of low catalytic activity of water electrolysis hydrogen production catalysts in alkaline electrolytes. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.
[0011] Figure 1 : XRD pattern of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 of the present invention;
[0012] Figure 2 : Scanning electron microscope image of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 of the present invention;
[0013] Figure 3 : EDS element distribution diagram of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 of the present invention;
[0014] Figure 4 : LSV polarization curves of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 of the present invention, the Co(OH)F / NF catalytic electrode prepared in Comparative Example 1, and the commercial Pt / C electrode in alkaline 1M KOH solution;
[0015] Figure 5: Tafel slope graph of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 of the present invention, the Co(OH)F / NF catalytic electrode prepared in Comparative Example 1, and the commercial Pt / C electrode in alkaline 1M KOH solution;
[0016] Figure 6 : LSV polarization curves of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 of the present invention before and after 3000 cycles in an alkaline 1 mol / L KOH solution. DETAILED DESCRIPTION
[0017] In order to better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments, but the content of the present invention is not limited to the following embodiments.
[0018] In the following examples, unless otherwise specified, the reagents are all commercially available chemical reagents.
[0019] Embodiment 1:
[0020] A method for preparing a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode, the preparation method is as follows:
[0021] (1) Weigh 0.37 g of ammonium fluoride and 0.75 g of urea, add them into a beaker containing 30 mL of water, and stir vigorously for 10 min to obtain a mixed solution A.
[0022] (2) Weigh 0.62 g of cobalt nitrate hexahydrate and 0.04 g of zinc nitrate hexahydrate, add them to mixed solution A, and stir vigorously for 10 min to obtain mixed solution B.
[0023] (3) The mixed solution B was transferred to a 50 mL reactor, and a piece of nickel foam was added to carry out a hydrothermal reaction. The temperature of the hydrothermal reaction was 100°C and the reaction time was 8 hours. After the hydrothermal reaction was completed, the reactor was naturally cooled to room temperature. The nickel foam in the reactor was then taken out, rinsed with water and anhydrous ethanol, and placed in a vacuum drying oven at 60°C for 6 hours to obtain ZnCo(OH)F / NF.
[0024] (4) Weigh 0.4804 g of sodium sulfide nonahydrate and add it to a beaker containing 20 mL of water and stir vigorously for 10 min. Add the dried ZnCo(OH)F / NF to the solution and react for 2 h, then take it out, rinse it with water and anhydrous ethanol, and place the nickel foam in a vacuum drying oven at 60° C. and dry it for 6 h to obtain ZnCo(OH)FS / NF.
[0025] Embodiment 2:
[0026] A method for preparing a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode, the preparation method is as follows:
[0027] (1) Weigh 0.37 g of ammonium fluoride and 0.75 g of urea, add them into a beaker containing 30 mL of water, and stir vigorously for 10 min to obtain a mixed solution A.
[0028] (2) Weigh 0.63 g of cobalt nitrate hexahydrate and 0.03 g of zinc nitrate hexahydrate, add them to mixed solution A, and stir vigorously for 10 min to obtain mixed solution B.
[0029] (3) The mixed solution B was transferred to a 50 mL reactor, and a piece of nickel foam was added to carry out a hydrothermal reaction. The temperature of the hydrothermal reaction was 100°C and the reaction time was 8 hours. After the hydrothermal reaction was completed, the reactor was naturally cooled to room temperature. The nickel foam in the reactor was then taken out, rinsed with water and anhydrous ethanol, and placed in a vacuum drying oven at 60°C for 6 hours to obtain ZnCo(OH)F / NF.
[0030] (4) Weigh 0.4804 g of sodium sulfide nonahydrate and add it to a beaker containing 20 mL of water and stir vigorously for 10 min. Add the dried ZnCo(OH)F / NF to the solution and react for 2 h, then take it out, rinse it with water and anhydrous ethanol, and place the nickel foam in a vacuum drying oven at 60° C. and dry it for 6 h to obtain ZnCo(OH)FS / NF.
[0031] Embodiment 3:
[0032] A method for preparing a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode, the preparation method is as follows:
[0033] (1) Weigh 0.37 g of ammonium fluoride and 0.75 g of urea, add them into a beaker containing 30 mL of water, and stir vigorously for 10 min to obtain a mixed solution A.
[0034] (2) Weigh 0.62 g of cobalt nitrate hexahydrate and 0.04 g of zinc nitrate hexahydrate, add them to mixed solution A, and stir vigorously for 10 min to obtain mixed solution B.
[0035] (3) The mixed solution B was transferred to a 50 mL reactor, and a piece of nickel foam was added to carry out a hydrothermal reaction. The temperature of the hydrothermal reaction was 100°C and the reaction time was 8 hours. After the hydrothermal reaction was completed, the reactor was naturally cooled to room temperature. The nickel foam in the reactor was then taken out, rinsed with water and anhydrous ethanol, and placed in a vacuum drying oven at 60°C for 6 hours to obtain ZnCo(OH)F / NF.
[0036] (4) Weigh 0.4804 g of sodium sulfide nonahydrate and add it to a beaker containing 20 mL of water and stir vigorously for 10 min. Add the dried ZnCo(OH)F / NF to the solution and react for 1 h, then take it out and rinse it with water and anhydrous ethanol. Place the nickel foam in a vacuum drying oven at 60° C. and dry it for 6 h to obtain ZnCo(OH)FS / NF.
[0037] Embodiment 4:
[0038] A method for preparing a ZnCo(OH)FS / NF hydrogen evolution catalytic electrode, the preparation method is as follows:
[0039] (1) Weigh 0.37 g of ammonium fluoride and 0.75 g of urea, add them into a beaker containing 30 mL of water, and stir vigorously for 10 min to obtain a mixed solution A.
[0040] (2) Weigh 0.62 g of cobalt nitrate hexahydrate and 0.04 g of zinc nitrate hexahydrate, add them to mixed solution A, and stir vigorously for 10 min to obtain mixed solution B.
[0041] (3) The mixed solution B was transferred to a 50 mL reactor, and a piece of nickel foam was added to carry out a hydrothermal reaction. The temperature of the hydrothermal reaction was 120°C and the reaction time was 5 hours. After the hydrothermal reaction was completed, the reactor was naturally cooled to room temperature. The nickel foam in the reactor was then taken out, rinsed with water and anhydrous ethanol, and dried in a vacuum drying oven at 60°C for 6 hours to obtain ZnCo(OH)F / NF.
[0042] (4) Weigh 0.4804 g of sodium sulfide nonahydrate and add it to a beaker containing 20 mL of water and stir vigorously for 10 min. Add the dried ZnCo(OH)F / NF to the solution and react for 2 h, then take it out, rinse it with water and anhydrous ethanol, and place the nickel foam in a vacuum drying oven at 60° C. and dry it for 6 h to obtain ZnCo(OH)FS / NF.
[0043] Comparative Example 1:
[0044] A method for preparing a Co(OH)F / NF hydrogen evolution catalytic electrode that is not doped with Zn ions and S ions, wherein the preparation method is as follows:
[0045] (1) Use an electronic balance to weigh 0.37 g of ammonium fluoride and 0.75 g of urea, add them into a beaker containing 30 mL of water, and stir vigorously for 10 min to obtain a mixed solution A.
[0046] (2) Using an electronic balance, weigh 0.66 g of cobalt nitrate hexahydrate, add it to mixed solution A, and stir vigorously for 10 min to obtain mixed solution B.
[0047] (3) The mixed solution B was transferred to a 50 mL reactor, and a piece of nickel foam was added to conduct a hydrothermal reaction. The temperature of the hydrothermal reaction was 100°C and the reaction time was 8 hours. After the hydrothermal reaction was completed, the reactor was naturally cooled to room temperature. The nickel foam in the reactor was then taken out, rinsed with water and anhydrous ethanol, and dried in a vacuum drying oven at 60°C for 6 hours to obtain Co(OH)F / NF.
[0048] Figure 1 This is the XRD pattern of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1. It can be clearly observed from the XRD pattern that in addition to the obvious Ni diffraction peaks (2θ=44.507°, 51.846°, 76.370°) corresponding to the (111), (200), and (220) crystal planes (PDF: 04-0850), the other diffraction peaks of the synthesized ZnCo(OH)FS / NF sample can all correspond to the standard card spectrum of Co(OH)F (PDF: 50-0827).
[0049] Figure 2 The SEM photographs of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 at different magnifications show that the ZnCo(OH)FS sample constructed on nickel foam under this condition presents a three-dimensional flower-like structure composed of clustered nanoneedles growing vertically on the nickel foam substrate.
[0050] Figure 3 This is the EDS element distribution diagram of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1. It can be found from the spectrum that Zn, Co, and S elements are evenly distributed on the nickel foam.
[0051] The electrochemical performance test process of ZnCo(OH)FS / NF hydrogen evolution catalytic electrode is as follows:
[0052] The nickel foam was cut into a size of 1cm×0.5cm and clamped in an electrode clamp to obtain a working electrode. The hydrogen evolution reaction (HER) by water electrolysis was carried out using a three-electrode test system. The carbon rod was used as the counter electrode, the mercury / mercuric oxide electrode was used as the reference electrode, and the Chenhua CHI660e electrochemical workstation was used for the test. The electrolyte tested was 1mol / L KOH.
[0053] Figure 4 The LSV polarization curves of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1, the Co(OH)F / NF catalytic electrode prepared in Comparative Example 1, and the commercial Pt / C electrode are shown in the figure. 2The overpotential corresponding to the current density is an evaluation parameter. The overpotential corresponding to Co(OH)F / NF in the comparative example is 193mV, while the overpotential corresponding to ZnCo(OH)FS / NF prepared in Example 1 is 55mV, which is better than the samples prepared in other examples. And this sample is only 18mV lower than the Pt / C noble metal catalyst with the best catalytic performance at present. This performance is better than most of the electrolytic water hydrogen evolution catalysts currently reported internationally.
[0054] Figure 5 The Tafel slope diagram of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1, the Co(OH)F / NF catalytic electrode prepared in Comparative Example 1, and the commercial Pt / C electrode. It can be seen from the figure that the Tafel slope of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 is only 56.9 mV / dec, which is much lower than that of the Co(OH)F / NF catalytic electrode prepared in Comparative Example 1 (136.1 mV / dec), and is close to that of the Pt / C catalytic electrode (52.3 mV / dec). Therefore, the ZnCo(OH)FS / NF catalytic electrode has a faster kinetic process and has excellent HER catalytic activity in alkaline electrolytes.
[0055] Figure 6 The LSV polarization curve of the ZnCo(OH)FS / NF catalytic electrode prepared in Example 1 before and after cycling. It can be seen from the figure that before and after 3000 CV cycles, the overpotential of the catalytic electrode only increased by 10 mV, proving that it has excellent electrochemical stability.
Claims
1. A method for preparing a ZnCo(OH)FS / NF electrocatalytic hydrogen evolution electrode, characterized in that: Follow these steps:
1. Dissolve ammonium fluoride and urea in water respectively to prepare a 0.01 mol / L ammonium fluoride solution and a 0.012 mol / L urea solution, and mix the two solutions to obtain a solution A; 2. Add cobalt nitrate hexahydrate and zinc nitrate hexahydrate into solution A and stir evenly to form solution B; 3. Adding the solution B into a hydrothermal reactor, and then adding nickel foam to carry out a hydrothermal reaction, and washing and drying the product to obtain ZnCo(OH)F / NF; Fourth, sodium sulfide nonahydrate is dissolved in water to prepare a sodium sulfide solution with a concentration of 0.1 mol / L, and the ZnCo(OH)F / NF obtained in the third step is immersed in the sodium sulfide solution at room temperature for 0.5 to 3 hours, and then taken out, washed and dried to obtain the electrocatalytic hydrogen evolution electrode.
2. The method for preparing a ZnCo(OH)FS / NF electrocatalytic hydrogen evolution electrode according to claim 1, characterized in that: The molar ratio of the cobalt nitrate hexahydrate to the zinc nitrate hexahydrate in step 2 is 1:(0.01-0.09), and the total concentration of the cobalt nitrate and the zinc nitrate in the prepared solution is 0.075 mol / L.
3. The method for preparing a ZnCo(OH)FS / NF electrocatalytic hydrogen evolution electrode according to claim 1, characterized in that The hydrothermal reaction temperature in step 3 is 90-120° C., and the reaction time is 5-10 hours.