A trimetallic phosphide, its preparation method and application

Abstract

This invention discloses a trimetallic phosphide, its preparation method, and its application, belonging to the field of electrolytic hydrogen production technology. The trimetallic phosphide is prepared using a stainless steel mesh as a substrate and an electrochemical deposition method. The metals in the electrodeposition solution during electrochemical deposition are cerium, iron, and nickel. The trimetallic phosphide prepared by this invention can be used as a high-performance water electrolysis catalyst that simultaneously optimizes reaction kinetics and reaction thermodynamics. It still has good catalytic effect, activity, and stability under alkaline conditions.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic hydrogen production technology, and particularly relates to a trimetallic phosphide, its preparation method and application. Background Technology

[0002] In today's energy-scarce world, researchers working on hydrogen evolution electrocatalysts (HER) have been diligently searching for a more affordable, readily available, safe, environmentally friendly, and highly efficient catalyst that maintains high stability even in complex environmental reactions. This would facilitate the industrialization of hydrogen production through water electrolysis, helping researchers obtain environmentally friendly energy and effectively addressing the energy and environmental problems caused by fossil fuel shortages and their use. Currently, known catalysts can be broadly categorized into three main types: The first type consists of noble metal catalysts, such as Pt, Ru, and Pd. These metals possess high stability and, due to their excellent catalytic activity and conductivity, have been favored by researchers. However, their high cost has prevented their industrial application. The second type comprises transition metal-based catalysts, which are less expensive than the aforementioned noble metals, developed through long-term experimental research. These catalysts can be further subdivided based on their chemical characteristics and the ratio of their components, including alloys, phosphides, sulfides, nitrides, and carbides. They also exhibit good hydrogen evolution reaction activity. These metal catalysts offer numerous advantages, including lower cost, easily controllable shape, and adjustable proportions, and demonstrate excellent catalytic performance regardless of the electrolyte solution in which they are placed. The third type is non-metallic catalysts. Currently, in addition to combining and doping metallic and non-metallic elements, various improvements have been made to the processing methods. The preparation methods used by those skilled in the art to synthesize transition metal catalysts are usually hydrothermal or calcination methods, introducing sulfur or phosphorus sources. These methods take a long time to prepare catalysts, have high trial and error costs, and are also prone to generating gases that pollute the environment, posing a potential safety threat to experimental personnel.

[0003] Meanwhile, existing transition metal phosphides have some defects under alkaline conditions (for example, the catalytic effect, activity and stability of transition metal phosphides under alkaline conditions cannot meet the requirements), which prevents them from meeting the needs of commercialization and large-scale production.

[0004] Therefore, it is necessary to find a water electrolysis hydrogen production material that is most cost-effective, has the simplest synthesis method, and has excellent catalytic performance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a trimetallic phosphide, its preparation method, and its application. The trimetallic phosphide of this invention can serve as a high-performance water electrolysis catalyst that simultaneously optimizes reaction kinetics and reaction thermodynamics.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions of the present invention:

[0008] This invention provides a method for preparing trimetallic phosphides, using stainless steel mesh as a substrate and electrochemical deposition to prepare trimetallic phosphides;

[0009] The metals in the electrodeposition solution during electrochemical deposition are cerium (Ce), iron (Fe), and nickel (Ni). Further, the molar ratio of Ce, Fe, Ni, and phosphorus is 0.75:21.5:30:(10-40), preferably 0.75:21.5:30:30.

[0010] Furthermore, the electrochemical deposition process employs cyclic voltammetry, with the voltage set from -1.2V to -0.6V.

[0011] Furthermore, the method for preparing the trimetallic phosphide includes the following steps:

[0012] Pre-treatment of stainless steel mesh;

[0013] Electrochemical deposition was performed on the pretreated stainless steel mesh using a cyclic voltammetry method with a voltage range of -1.2V to -0.6V.

[0014] Furthermore, the pretreatment process for the stainless steel mesh is as follows:

[0015] Cut the stainless steel mesh into 1cm×2.5cm pieces, sand them with sandpaper, place the sanded stainless steel mesh in hydrochloric acid and sonicate for 30 minutes, then sonicate with anhydrous ethanol and water for 20 minutes each, and finally dry.

[0016] Furthermore, the stainless steel mesh has a mesh count of 600-2000, preferably 600, 1200, 1400 or 2000, and more preferably 1400.

[0017] Furthermore, the pretreatment process for the stainless steel mesh is as follows:

[0018] Prepare a 1400-mesh stainless steel mesh and cut it into 1cm x 2.5cm pieces as the conductive substrate. To ensure the generation of more active sites, use 400-mesh sandpaper to polish the conductive substrate stainless steel mesh. First, immerse the polished stainless steel mesh in a 3mol / L hydrochloric acid solution and sonicate for 30 minutes to remove inorganic impurities and oxidized parts from the surface. Then, place the treated substrate in anhydrous ethanol and sonicate for 20 minutes to remove organic impurities from the conductive substrate. Finally, place the treated substrate in deionized water and sonicate for 20 minutes. Finally, remove it and dry it in a vacuum drying oven for later use.

[0019] Furthermore, the number of electrochemical deposition cycles is 14-42 cycles (CV), preferably 14 cycles, 28 cycles, 35 cycles or 42 cycles, more preferably 35 cycles.

[0020] Furthermore, the phosphorus (P) source in the electrolyte during electrochemical deposition is NaH2PO2·H2O.

[0021] Furthermore, to prevent the deposited iron from oxidizing in the air, a drying process is performed after the electrochemical deposition is completed.

[0022] Furthermore, the electrochemical deposition process is as follows:

[0023] 0.75 mmol Ce(NO3)2·6H2O, 21.5 mmol FeSO4·7H2O, 30 mmol Ni(NO3)2·6H2O, 30 mmol NH4F and 30 mmol NaH2PO2·H2O were dissolved in 50 mL of deionized water to prepare the electrodeposition solution.

[0024] Electrochemical deposition was performed on the pretreated stainless steel mesh using a cyclic voltammetry method with a voltage range of -1.2V to -0.6V. The mesh was then dried after electrochemical deposition.

[0025] This invention utilizes the combined action of multiple transition metals and phosphorus (P) to obtain trimetallic phosphides that exhibit stronger catalytic performance compared to single-metal doping or bimetallic phosphides. Ce, as one of the most abundant rare earth metals, possesses a unique orbital structure, exhibiting not only strong oxyphilicity but also excellent electrical conductivity. In this invention, the addition of Ce enhances the catalyst's hydrogen evolution reaction (HER). In the trimetallic phosphides of this invention, the roles of metals and phosphorus are both distinct and synergistic; the ratio of metals to phosphorus affects the catalytic activity of the catalyst.

[0026] The second technical solution of the present invention:

[0027] The present invention also provides a trimetallic phosphide prepared by the above method, which can be used as a high-performance water electrolysis catalyst that simultaneously optimizes reaction kinetics and reaction thermodynamics.

[0028] The third technical solution of the present invention:

[0029] The present invention also provides the application of the aforementioned trimetallic phosphide in hydrogen production by water electrolysis.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] (1) The preparation method of the trimetallic phosphide of the present invention is simple and environmentally friendly, and can meet the needs of commercialization and large-scale production;

[0032] (2) The trimetallic phosphide of the present invention can serve as a high-performance water electrolysis catalyst that simultaneously optimizes reaction kinetics and reaction thermodynamics, when the current density is 10 mV·cm -2 At this time, the overpotential is 61.6mV, the impedance is at its minimum, and the Tafel slope is 34mV·dec. -1 The double-layer capacitance is 53.2 mF·cm. -2 It exhibits good catalytic effect, activity and stability under alkaline conditions. Attached Figure Description

[0033] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0034] Figure 1 C for Ni / Ce / Fe / P-14CV, Ni / Ce / Fe / P-28CV, Ni / Ce / Fe / P-35CV, and Ni / Ce / Fe / P-42CV dl Value plot (a) and EIS plot (b);

[0035] Figure 2 The CV curves are for Ni / Ce / Fe / P-14 cycles (a), Ni / Ce / Fe / P-28 cycles (b), Ni / Ce / Fe / P-35 cycles (c), and Ni / Ce / Fe / P-42 cycles (d).

[0036] Figure 3 Tafel slope (a) and LSV plot (b) of trimetallic phosphide samples with different scan numbers;

[0037] Figure 4 Ni / Ce / Fe / P-600 mesh (600 mesh), Ni / Ce / Fe / P-1400 mesh (1400 mesh), Ni / Ce / Fe / P-1600 mesh (1600 mesh), Ni / Ce / Fe / P-2000 mesh (2000 mesh) dl Value plot (a) and EIS plot (b);

[0038] Figure 5 Electrode materials of Ni / Ce / Fe / P-600 mesh (a), Ni / Ce / Fe / P-1400 mesh (b), Ni / Ce / Fe / P-1600 mesh (c), and Ni / Ce / Fe / P-2000 mesh (d) were subjected to scanning at 1 M KOH solution at scan rates of 10, 20, 30, 40, and 50 mV·s. -1 The CV curve;

[0039] Figure 6 Tafel slope (a) and LSV plot (b) of trimetallic phosphide samples with different scan numbers;

[0040] Figure 7 C for Ni / Ce / Fe / P-10mmol, Ni / Ce / Fe / P-20mmol, Ni / Ce / Fe / P-30mmol, and Ni / Ce / Fe / P-40mmol dl Value plot (a) and EIS plot (b);

[0041] Figure 8 Electrode materials with Ni / Ce / Fe / P-10mmol (a), Ni / Ce / Fe / P-20mmol (b), Ni / Ce / Fe / P-30mmol (c), and Ni / Ce / Fe / P-40mmol (d) were subjected to scanning at 1 M KOH solution at scan rates of 10, 20, 30, 40, and 50 mV·s. -1 The CV curve;

[0042] Figure 9 Tafel slope (a) and LSV plot (b) of trimetallic phosphide samples with different scan numbers;

[0043] Figure 10 The stability of the trimetallic phosphide in Example 1. Detailed Implementation

[0044] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0045] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0046] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0047] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0048] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0049] All raw materials used in the embodiments of this invention were obtained through commercial purchase.

[0050] The technical solution of the present invention will be further illustrated by the following embodiments.

[0051] Example 1

[0052] Stainless steel mesh pretreatment: Prepare 1400 mesh stainless steel mesh and cut it into 1cm × 2.5cm pieces as the conductive substrate. To ensure the generation of more active sites, use 400-grit sandpaper to polish the conductive substrate stainless steel mesh. First, immerse the polished stainless steel mesh in a 3mol / L hydrochloric acid solution and sonicate for 30 minutes to remove inorganic impurities and oxides from the surface. Then, place the treated substrate in anhydrous ethanol and sonicate for 20 minutes to remove organic impurities from the conductive substrate. Finally, place the treated substrate in deionized water and sonicate for 20 minutes. Finally, remove it and dry it in a vacuum drying oven for later use.

[0053] Electrochemical deposition:

[0054] 0.75 mmol Ce(NO3)2·6H2O, 21.5 mmol FeSO4·7H2O, 30 mmol Ni(NO3)2·6H2O, 30 mmol NH4F and 30 mmol NaH2PO2·H2O were dissolved in 50 mL of deionized water to prepare the electrodeposition solution.

[0055] The pretreated stainless steel mesh was electrochemically deposited using a cyclic voltammetry method with a voltage range of -1.2V to -0.6V. The electrochemical deposition cycle consisted of 35 cycles. After the electrochemical deposition was completed, the mesh was dried to obtain a trimetallic phosphide, denoted as Ni / Ce / Fe / P-35CV (Ni / Ce / Fe / P-1400 mesh, Ni / Ce / Fe / P-30mmol).

[0056] Example 2

[0057] Same as Example 1, except that the stainless steel mesh is 600 mesh, denoted as Ni / Ce / Fe / P-600 mesh.

[0058] Example 3

[0059] Same as Example 1, except that the stainless steel mesh is 1200 mesh, denoted as Ni / Ce / Fe / P-1200 mesh.

[0060] Example 4

[0061] Same as Example 1, except that the stainless steel mesh is 2000 mesh, denoted as Ni / Ce / Fe / P-2000 mesh.

[0062] Example 5

[0063] Same as Example 1, except that the amount of NaH2PO2·H2O in the electrodeposition solution is 10 mmol, denoted as Ni / Ce / Fe / P-10mmol.

[0064] Example 6

[0065] Same as Example 1, except that the amount of NaH2PO2·H2O in the electrodeposition solution is 20 mmol, denoted as Ni / Ce / Fe / P-20mmol.

[0066] Example 7

[0067] Same as Example 1, except that the amount of NaH2PO2·H2O in the electrodeposition solution is 40 mmol, denoted as Ni / Ce / Fe / P-40mmol.

[0068] Example 8

[0069] Same as Example 1, except that the number of electrochemical deposition cycles is 14, denoted as Ni / Ce / Fe / P-14CV.

[0070] Example 9

[0071] Same as Example 1, except that the number of electrochemical deposition cycles is 28, denoted as Ni / Ce / Fe / P-28CV.

[0072] Example 10

[0073] Same as Example 1, except that the number of electrochemical deposition cycles is 42, denoted as Ni / Ce / Fe / P-42CV.

[0074] Before commencing electrochemical data collection, the first preparatory step is to pre-treat the glassy carbon electrode to effectively improve its sensitivity in electrochemical reactions and enhance the accuracy of sample testing. This involves preparing chamois leather, alumina polishing powder, and distilled water for polishing the glassy carbon electrode. The specific steps are as follows: evenly sprinkle the polishing powder onto a circular chamois, add a small amount of distilled water, and stir with the insulating part of the glassy carbon electrode to thoroughly mix the water and alumina polishing powder into a uniform slurry. Holding the glassy carbon electrode with a still wrist, apply force with your arm, keeping the chamois and the glassy carbon electrode surface perpendicular, and slowly and evenly move the chamois in a figure-eight pattern on the chamois surface filled with the alumina polishing powder slurry. It is crucial not to change the path to a parallel figure-one, as this will scratch the electrode surface. Next, rinse the polished glassy carbon electrode with distilled water. First, check if there are any scratches on the surface. If so, continue polishing until smooth. If there are no scratches visible to the naked eye, place it in an ultrasonic water bath for 2-3 minutes and repeat 3 times.

[0075] After cleaning, switch the electrochemical workstation to cyclic voltammetry mode, using a mixed solution of 0.2M KNO3 and 0.01M K3Fe(C2N)6, set the scan voltage to 0-0.6V, and the scan speed to 50mV / s. The formal experimental measurement can only be carried out when the peak difference of the scanned image is less than 80mV. If the value is greater than 80mV, the polishing process will be repeated until the test results meet the standard before proceeding to the next step.

[0076] The three-electrode system was used, and the test was conducted under normal temperature and pressure conditions. Before starting the measurement, a 1 mol / L (pH=14) potassium hydroxide solution was prepared as the electrolyte solution for the electrode reaction in this experiment. The working electrode was prepared with dimensions of 1 cm × 3 cm. The prepared working electrode sample was wrapped with plastic wrap to form a square with a side length of 1 × 1 cm, so that the area reached 1 cm². -2 To facilitate data calculation, a Pt electrode was used as the counter electrode and an Hg / HgO electrode as the reference electrode. After all the testing instruments were in place, high-purity nitrogen gas was first introduced into the system for 15 minutes to purge the air and ensure the experiment was conducted safely in an inert atmosphere. A magnetic stirrer was prepared and used to stir the 1 M KOH solution at a low speed to ensure that the generated gas could be desorbed in time.

[0077] After completing the above preparations, iR compensation should be performed first, followed by 5 cycles of voltammetric activation of the sample, and then linear sweep voltammetry (LSV) should be performed with a scan rate of 5 mV·s. -1 Electrochemical impedance spectroscopy (EIS) values ​​were obtained by setting the open-circuit voltage to 3 mV and using the LSV curve to find the flat region where no redox reaction occurred. The CV scan rate was 10–50 mV·s. -1 The curve showing the change of current density over time, at a current density of 10 mA·cm⁻¹ -2 Chronoamperometry was performed at the corresponding potential. The stability of the sample was measured using the chronoamperometry method, and it could be maintained continuously for 24 hours. The Tafel slope value was obtained from the LSV curve.

[0078] like Figure 1 As shown, Figure 1 Figure (a) characterizes the charge-discharge of the double-layer current in the trimetallic phosphide Ni / Ce / Fe / P at scan numbers of 14, 28, 35, and 42. The potential range values ​​are taken from the non-Radial current range where no electrochemical reaction occurs and no redox reaction takes place, thus allowing for a more accurate determination of the double-layer capacitance. Figure (b) characterizes the electrochemical impedance at the aforementioned different scan numbers. When catalysts composed of Ni, Ce, and Fe form covalent bonds, under the synergistic effect of these three metals, and with the addition of an equal mass of NaH2PO2·H2O as the phosphorus source, the... Figure 1 Observations show that the trimetallic phosphide sample scanned for 35 cycles exhibited the most prominent catalytic effect among the four different variables. The slope obtained after linear fitting of the cyclic voltammetric curve difference was the largest, five times that of the sample scanned for 14 cycles, and twice that of the samples scanned for 28 and 42 cycles. This indicates a significant advantage in catalytic effect from the working electrode. Figure 1 In the electrochemical impedance spectroscopy (EIS) of (b), it can be seen that the 28-circle scan has a larger semicircle, which indicates that the 28-circle sample is less likely to be polarized during the electrochemical reaction compared to the sample with a smaller semicircle. Figure 1 In (b), the impedance results for 35 and 42 scan cycles are very close. However, the arc of the EIS plot for the sample with 35 scan cycles is always directly below that of the sample with 42 scan cycles, indicating that the sample with 35 scan cycles has a smaller charge transfer resistance (R0). ct ), corresponding to Figure 1 The value of the ordinate of the arc in (b). Figure 1In (b), the sample with the highest impedance was the one with 14 scans, followed by the sample with 28 scans. The main reason for this result is likely related to the number of active sites formed on the substrate during the electrochemical deposition of the working electrode samples. When the number of scans is relatively small, the number of reactive particles deposited on the substrate surface is small, resulting in fewer active sites. The deposited particles cannot be evenly and fully distributed on the surface of the electrode material, resulting in a smaller overall active area and a larger impedance result. However, the number of scans should not be too large, as this will cause an excessive number of particles on the surface, leading to particle aggregation and clogging of the gaps in the stainless steel mesh. This will reduce the porosity, thereby reducing the relative surface area and the relative contact area between the solution and the catalyst surface, which in turn reduces the catalytic effect. Only an appropriate number of deposition scans can bring a suitable number of particles to the substrate surface, allowing the electrocatalytic hydrogen evolution reaction to proceed more quickly.

[0079] The CV curves for Ni / Ce / Fe / P with 14 scans (a), 28 scans (b), 35 scans (c), and 42 scans (d) are shown below. Figure 2 Tafel slopes (a) and LSV plots (b) of trimetallic phosphide samples with different scan numbers are shown in [reference needed]. Figure 3 .from Figure 2 It can be observed that the Ni / Ce / Fe / P prepared under different scan cycles exhibits a larger electrochemical active area at 35 scan cycles, which also means that Ni / Ce / Fe / P has a larger active area. Figure 3 As can be seen from the data, among all catalytic electrode materials with a scanning cycle count of 35 cycles, when the current density is 10 mA·cm⁻¹ -2 At that time, the curve was at the bottom of the four samples. When the electrochemical reaction was carried out in 1 M KOH solution, the current density reached 10 mA·cm⁻¹. -2 The overpotential is 64mV, which is closest to the curve of the standard glassy carbon electrode. According to... Figure 3 In (b), it can be more clearly observed that the Tafel slope corresponding to the sample scanned for 35 laps is the smallest, at 38.7 mV·dec. -1 This demonstrates that the material itself possesses excellent HER kinetics. It is intuitively understood that the sample prepared under 35 scan cycles exhibits a faster reaction rate and more rapid charge movement during electrochemical reactions. To achieve the same current density in the reaction, only a small overpotential is required, implying that the electrode material prepared under 35 scan cycles participates in the catalytic reaction with a faster electron transport rate. In summary, the electrode material prepared under the 35-scan condition exhibits a larger active area, a greater number of active sites, and uniform deposition of the transition metal phosphides participating in the reaction on the stainless steel mesh substrate.

[0080] Figure 4 (a) shows the double-layer capacitance values ​​for Ni / Ce / Fe / P using different mesh sizes of stainless steel mesh substrates (600 mesh, 1400 mesh, 1600 mesh, and 2000 mesh) as the framework; (b) shows the electrochemical impedance spectroscopy corresponding to the above different mesh sizes. When the phosphorus source is the same mass of NaH2PO2·H2O, and the number of deposition cycles is 35, the catalytic effect is most significant with 1400 mesh stainless steel mesh as the substrate. The double-layer capacitance of 1400 mesh stainless steel mesh is twice that of 1600 mesh stainless steel mesh, and the charge movement at the interface is also faster. However, when using 1600 mesh stainless steel mesh as the substrate in the electrode reaction, electron transfer in the electrochemical reaction is constrained. This may be because the selected mesh size is too large, causing the metal deposited on the surface of the 1600 mesh stainless steel mesh to clog the gaps between the mesh surfaces after electrodeposition, resulting in a decrease in the relative specific surface area of ​​the electrode and a decrease in the relative contact area with the solution. Further comparison... Figure 4 In the electrochemical impedance spectroscopy of (b), the electrochemical impedance spectroscopy corresponding to the 600-mesh stainless steel mesh and the 1400-mesh stainless steel mesh substrate can be observed. Among all mesh sizes, the 600-mesh stainless steel mesh has the largest radius in the electrochemical impedance spectroscopy, while the radius of the other impedance spectroscopy ... In general, when selecting substrate materials, one should not choose materials with relatively small mesh sizes simply because of price considerations, as this would result in the substrate material not providing enough adhesion area for the deposited metal material. This would lead to an effective number of catalysts being stacked, and the relative contact area between the solution and the catalyst surface would be very small, thereby reducing the catalytic effect of the reaction. On the other hand, one should not only consider the relative area size and ignore the positive impact of porosity on catalysis.

[0081] Electrode materials of Ni / Ce / Fe / P-600 mesh (a), Ni / Ce / Fe / P-1400 mesh (b), Ni / Ce / Fe / P-1600 mesh (c), and Ni / Ce / Fe / P-2000 mesh (d) were subjected to scanning at 1 M KOH solution at scan rates of 10, 20, 30, 40, and 50 mV·s. -1 The CV curve is shown below. Figure 5 , Figure 5The study observed that Ni / Ce / Fe / P prepared on stainless steel mesh substrates with different mesh sizes exhibited a larger electrochemical active area on the 1400-mesh stainless steel mesh substrate, which also means that the 1400-mesh Ni / Ce / Fe / P has better catalytic activity for hydrogen production by water electrolysis.

[0082] Figure 6 In (b), the measured data are for the same mass of NaH2PO2·H2O, using 35 scan cycles. In the LSV plot, among the curves for four different mesh sizes, the 1400 mesh curve is at the bottom. The experimental data indicates that when an electrochemical reaction is carried out in 1 M KOH solution, the current density reaches 10 mA·cm⁻¹. -2 The overpotential is 64mV. According to... Figure 6 In (a), the 1400-mesh stainless steel mesh substrate can be observed more clearly, and the corresponding Tafel slope is the smallest, at 41.7 mV·dec. -1 This study demonstrates the excellent HER kinetics of the material itself, providing a more intuitive understanding that the electrochemical reaction proceeds faster with a 1400-mesh stainless steel mesh substrate. Compared to other mesh substrates, charge movement is faster, and only a small overpotential is needed to achieve the same current density. This implies that the electron transport rate is faster with the 1400-mesh substrate electrode material participating in the catalytic reaction compared to the other three. In summary, the electrode material prepared on the 1400-mesh substrate exhibits a larger active area and a greater number of active sites. The transition metal phosphides involved in the reaction are deposited in a sufficiently uniform quantity on the stainless steel mesh substrate, avoiding both insufficient active surface area due to excessive substrate porosity and reduced contact surface area between the solution and the catalyst due to insufficient porosity. An appropriate substrate mesh size allows the electrode material to have a suitable number and size of porosity on its surface after electrochemical deposition, ensuring sufficient contact with the solution and enhancing the catalytic activity of the catalyst in water electrolysis and hydrogen evolution.

[0083] Figure 7 The main discussion focuses on verifying the effect of adding different molar masses of NaH2PO3·H2O on the catalytic performance of the catalyst using a 1400-mesh stainless steel mesh substrate and 35 scanning revolutions. Figure 7 Figure (b) characterizes the electrochemical impedance of different masses of NaH2PO3·H2O, which is obtained by... Figure 7The observation in (a) shows that the addition of 30 mmol NaH2PO3·H2O has the most favorable catalytic effect on the overall Ni / Ce / Fe / P, with the largest double-layer capacitance. This also means that the electron transfer rate of the catalytic material with 30 mmol is about twice that of 20 mmol and 40 mmol in the electrochemical reaction, and the charge movement at the interface is also faster than that with 10 mmol. This indicates that under the combined effect of the three metals, the amount of P added cannot be too much. Too much will reduce the amount of metal deposition, reduce the electron transfer capacity of the material, and restrict the electron transfer rate in the reaction; too little will not achieve the corresponding catalytic effect. Figure 7 This view is also confirmed in (b). The arc radius formed by 10 mmol of NaH2PO3·H2O is the largest, corresponding to the largest impedance value. The electrocatalyst made from it is not easily polarized. The next values ​​are 20 mmol and 40 mmol. In general, finding the optimal doping amount of NaH2PO3·H2O plays an indispensable role in the electrode reaction and is an essential step.

[0084] in accordance with Figure 8 It can be observed that the Ni / Ce / Fe / P sample prepared with a 1400-mesh stainless steel mesh as the substrate after 35 deposition cycles exhibits a larger electrochemical active area when 30 mmol of solution is deposited with NaH2PO3·H2O as the phosphorus source. This also means that Ni / Ce / Fe / P has a larger active area. This can also be observed through... Figure 3 In the LSV plot (b), it was observed that among the four phosphorus source catalytic electrode materials with different addition amounts, the curve for 30 mmol NaH2PO3·H2O was at the bottom and closest to the value of 25% Pt / C. When the electrochemical reaction was carried out in 1M KOH solution, the current density reached 10 mA·cm⁻¹. -2 The overpotential was 61.6 mV. Simultaneously, the HER image will provide a specific range for measuring ECSA. The flattest region in the obtained curve is chosen as the center; this range represents the interval where the electrode material has not undergone redox reaction, and the Faraday capacitance is small. This method is one of the means to obtain non-Faraday current. In this experiment, a voltage range of approximately 50 mV was selected as the numerical range for measuring the CV curve. According to... Figure 8 In (a), it can be more clearly observed that the Tafel slope of the electrode material obtained by electrochemical deposition with the addition of 30 mmol of phosphorus source is the smallest, at 34 mV·dec. -1The study showcased the excellent electrochemical reaction (HER) kinetics of Ni / Ce / Fe / P deposited on a 1400-mesh stainless steel mesh substrate with 30 mmol NaH₂PO₃·H₂O as the phosphorus source. Compared to other materials, Ni / Ce / Fe / P exhibited faster charge movement. The addition of 30 mmol phosphorus resulted in a faster electrochemical reaction rate. Furthermore, only a small overpotential was required to achieve the same current density, indicating a faster electron transport rate. In summary, the electrode material deposited in the 30 mmol NaH₂PO₃·H₂O electrolyte solution exhibited a larger electrochemical active area and a greater number of active sites. Appropriate phosphorus doping avoided both excessive P leading to a reduced deposition rate of the Ni / Ce / Fe / P trimetallic structure and insufficient P resulting in inadequate catalytic activity; thus, appropriate P doping enhanced the catalyst's catalytic activity.

[0085] Tafel slopes (a) and LSV plots (b) of trimetallic phosphide samples with different scan numbers are shown in [reference needed]. Figure 9 .

[0086] Figure 10 The stability of the trimetallic phosphide sample in Example 1 was measured. The stability is also an important indicator of the ability of a water electrolysis hydrogen evolution catalyst. The present invention uses the chronoamperometry method to test the sample continuously for 24 hours. The test results show that the sample has good durability of catalytic ability.

[0087] This invention prepares a novel trimetallic phosphide electrode material, Ni / Ce / Fe / P, via electrochemical deposition. To identify the optimal phosphorus source doping concentration, four groups of electrode materials deposited with electrolyte solutions containing 10 mmol, 20 mmol, 30 mmol, and 40 mmol of NaH₂PO₂·H₂O were compared to assess their catalytic performance. Electrode materials deposited on 600-mesh, 1400-mesh, 1600-mesh, and 2000-mesh stainless steel mesh substrates were also compared. Four groups of samples with different deposition cycles (14, 28, 35, and 42 cycles) were used with 1 MkOH solution. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were measured using a three-electrode system on an electrochemical workstation. The results showed that the trimetallic phosphide exhibited a 20 mV reduction in overpotential compared to the bimetallic phosphide. It also maintained its activity after 24 hours of continuous operation.

[0088] (1) By comparing the HER, EIS, and CV diagrams of samples deposited for 14, 28, 35, and 42 cycles, double-layer capacitance and Tafel slope diagrams were plotted. The results showed that the electrode material deposited at 35 CV cycles had the best catalytic effect at a current density of 10 mA·cm⁻¹. -2The overpotential is 61.6 mV, and the Tafel slope is 38.7 mV·dec. -1 This demonstrates that the catalytic electrode at 35 CV exhibits the best catalytic performance.

[0089] (2) Electrochemical performance tests were conducted on 600-mesh, 1400-mesh, 1600-mesh, and 2000-mesh stainless steel meshes with 35 scanning circles. The results showed that the 1400-mesh stainless steel mesh, as a substrate material for electrodeposition, possessed excellent electrocatalytic hydrogen evolution performance at a current density of 10 mA·cm⁻¹. -2 The overpotential is 61.6 mV, and the Tafel slope is 41.7 mV·dec. -1 This proves that the 1400-mesh catalytic electrode has the best catalytic effect.

[0090] HER, EIS, and CV plots were measured and analyzed using electrolyte solutions composed of 10 mmol, 20 mmol, 30 mmol, and 40 mmol NaH₂PO₃·H₂O, and Tafel slope plots were generated. The results showed that the electrodeposited electrode material in the 30 mmol NaH₂PO₃·H₂O solution exhibited the best catalytic effect at a current density of 10 mA·cm⁻¹. -2 The overpotential is 61.6 mV. It has the smallest radius of curvature in the EIS plot and exhibits a faster polarization rate.

[0091] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. Use of a trimetallic phosphide in the production of hydrogen by electrolysis of water, characterized in that, The preparation method of the three-metal phosphide is: Stainless steel mesh pretreatment: prepare 1400 mesh stainless steel mesh, cut it into 1 cm x 2.5 cm as a conductive substrate, polish the conductive substrate stainless steel mesh using 400 mesh sandpaper; immerse the polished stainless steel mesh in a 3 mol / L hydrochloric acid solution and ultrasonic for 30 min to remove the surface inorganic impurities and oxidation parts, again place the treated substrate in anhydrous ethanol and ultrasonic for 20 min to remove the organic impurities of the conductive substrate, finally place the treated substrate in deionized water and ultrasonic for 20 min, and finally take out and dry in a vacuum drying oven; When electrochemical deposition, 0.75 mmol Ce(NO3)2·6H2O, 21.5 mmol FeSO4·7H2O, 30 mmol Ni(NO3)2·6H2O, 30 mmol NH4F and 30 mmol NaH2PO2·H2O are dissolved in 50 mL of deionized water as an electrodeposition solution; Using cyclic voltammetry, set the voltage to -1.2V to -0.6V, electrochemically deposit the pretreated stainless steel mesh, the electrochemical deposition cycle is 35 cycles, after electrochemical deposition, drying is performed, and the three-metal phosphide is obtained.

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