Rare earth oxide-based electrocatalytic material and application thereof

Abstract

This invention belongs to the field of electrocatalysis and discloses a rare earth oxide-based electrocatalytic material and its application. The rare earth oxide-based electrocatalytic material comprises FeNi3 / RE2O3, where RE represents a rare earth element. In the rare earth oxide-based electrocatalytic material provided by this invention, the unique 4f electrons of RE2O3 regulate the electronic structure of FeNi3, optimizing the adsorption energy barrier of protonated hydrogen on the catalyst surface, regulating the adsorption state of hydrogen evolution intermediates on the catalyst surface, accelerating the reaction kinetics of the catalyst, and enabling the catalyst to exhibit satisfactory electrocatalytic hydrogen evolution activity in alkaline media. It has the potential for application in the electrolytic water electrolysis hydrogen production industry, with significant practical and economic value.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis, specifically relating to a rare earth oxide-based electrocatalytic material and its application. Background Technology

[0002] Currently, human socio-economic development heavily relies on fossil fuels. Due to the non-renewable nature of fossil fuels, the pressure of energy shortages is increasing. Simultaneously, the overuse of fossil fuels has triggered a series of ecological and environmental problems. Against this backdrop, hydrogen, as the cleanest and most efficient energy source, plays a crucial role in alleviating the energy crisis and environmental issues through large-scale production. Compared to the widely used fossil fuel-based hydrogen production methods, water electrolysis offers advantages such as high hydrogen purity and low carbon emissions, thus attracting widespread attention. Among the currently developed water electrolysis hydrogen production technologies, alkaline water electrolysis shows promising application prospects due to its cost-effective equipment. Platinum is considered the most efficient catalyst for water electrolysis hydrogen production. However, there is still significant room for improvement in the hydrogen evolution activity of platinum in alkaline media. Furthermore, the scarcity and high cost of precious metals also limit their large-scale commercial application in water electrolysis hydrogen production technology.

[0003] Rare earth elements, due to their unique 4f electronic structure and special physical and chemical structures, have wide applications in military technology, petrochemicals, metallurgy, and glass ceramics, and are known as "industrial gold" and "industrial vitamins." They also have relatively wide applications in the field of electrocatalysis.

[0004] Therefore, how to cleverly utilize the unique 4f electron structure of rare earth elements to improve the catalytic performance of catalysts and prepare a low-cost, high-activity non-platinum-based electrocatalytic hydrogen evolution material is a key challenge in this field. Summary of the Invention

[0005] In view of the above-mentioned problems in the prior art, the purpose of this invention is to provide an electrocatalytic hydrogen evolution electrode, its preparation method and application.

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

[0007] In a first aspect, the present invention provides a rare earth oxide-based electrocatalytic material, wherein the rare earth oxide-based electrocatalytic material comprises FeNi3 / RE2O3, wherein RE is a rare earth element.

[0008] In the rare-earth oxide-based electrocatalytic material provided by this invention, the unique 4f electrons of RE2O3 modulate the electronic structure of FeNi3, optimizing the adsorption energy barrier of protonated hydrogen on the catalyst surface, regulating the adsorption state of hydrogen evolution intermediates on the catalyst surface, accelerating the reaction kinetics of the catalyst, and enabling the catalyst to exhibit satisfactory electrocatalytic hydrogen evolution activity in alkaline media. It has the potential for application in the water electrolysis hydrogen production industry, and its practical and economic value is significant.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0010] Preferably, RE is at least one of Pr, Sm, Nd and Pr.

[0011] Preferably, in the rare earth oxide-based electrocatalytic material, the molar ratio of Fe to RE is 1:(0.04-1.5), for example, 1:0.04, 1:0.05, 1:0.06, 1:0.08, 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:1, 1:1.3, or 1:1.5.

[0012] In a second aspect, the present invention provides an electrocatalytic hydrogen evolution electrode, the electrocatalytic hydrogen evolution electrode comprising a conductive substrate and a catalyst layer supported on the surface of the conductive substrate, wherein the catalyst in the catalyst layer comprises the rare earth oxide-based electrocatalytic material described in the first aspect.

[0013] In the electrocatalytic hydrogen evolution electrode of the present invention, the conductive substrate plays a supporting role, and the electrocatalytic hydrogen evolution electrode exhibits high electrocatalytic hydrogen evolution activity in alkaline medium.

[0014] Preferably, the conductive substrate is nickel foam.

[0015] Thirdly, the present invention provides a method for preparing an electrocatalytic hydrogen evolution electrode as described in the second aspect, the method comprising the following steps:

[0016] (1) An electrodeposition solution was prepared using nickel source, iron source and rare earth source;

[0017] (2) Using a conductive substrate as a cathode, electrodeposition is performed in the electrodeposition solution to obtain a NiFe-LDH / RE(OH)3 precursor layer on the surface of the conductive substrate.

[0018] (3) The conductive substrate loaded with the NiFe-LDH / RE(OH)3 precursor layer is calcined to obtain the electrocatalytic hydrogen evolution electrode.

[0019] This invention utilizes a simple electrochemical deposition method to prepare a high-performance electrocatalytic hydrogen evolution electrode. This preparation method is simple, rapid, and efficient, and uses inexpensive chemicals. The method is economical in terms of preparation cost and feasible for industrial application, and has great application prospects in the field of industrial water electrolysis.

[0020] Meanwhile, the above-mentioned preparation method also prepared the rare earth oxide-based electrocatalytic material described in the first aspect, which was loaded on a conductive substrate in the form of a catalyst layer to form an electrocatalytic hydrogen evolution electrode.

[0021] Preferably, the nickel source in step (1) is a water-soluble nickel salt, preferably including nickel nitrate.

[0022] Preferably, the mass concentration of the nickel source in the electrodeposition solution in step (1) is 15 g / L to 25 g / L, for example, it can be 15 g / L, 16 g / L, 17 g / L, 18 g / L, 20 g / L, 21 g / L, 22 g / L, 23 g / L or 25 g / L.

[0023] Preferably, the iron source in step (1) is a water-soluble iron salt, preferably including ferric nitrate.

[0024] Preferably, the mass concentration of the iron source in the electrodeposition solution in step (1) is 5 g / L to 15 g / L, for example, it can be 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 12 g / L, 13 g / L or 15 g / L.

[0025] Preferably, the rare earth source in step (1) is a water-soluble rare earth salt, preferably including praseodymium nitrate.

[0026] Preferably, the mass concentration of the rare earth source in the electrodeposition solution in step (1) is 1 g / L to 10 g / L, for example, it can be 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L or 10 g / L.

[0027] Preferably, the solvent in the electrodeposition solution in step (1) is water. The water can be deionized water.

[0028] As a preferred technical solution for the preparation method of the electrocatalytic hydrogen evolution electrode of the present invention, in the electrodeposition process of step (2), a platinum sheet is used as the anode.

[0029] Preferably, the conductive substrate is nickel foam.

[0030] Preferably, the nickel foam is pretreated before use.

[0031] Preferably, the pretreatment is performed by sequentially using acetone, HCl, water and ethanol for ultrasonic treatment to remove grease and oxide layer from the surface of the nickel foam and improve the electrodeposition effect.

[0032] In one embodiment, pretreatment is performed by sonicating with acetone for 15 minutes, with 3 mol / L HCl for 30 minutes, with deionized water for 15 minutes, and with anhydrous ethanol for 15 minutes.

[0033] Preferably, during the electrodeposition process in step (2), the voltage is -0.5V to -1.5V, for example, it can be -0.5V, -0.6V, -0.8V, -1.0V, -1.1V, -1.2V, -1.4V or -1.5V, etc.

[0034] Preferably, the electrodeposition time in step (2) is 400s to 1800s, for example, it can be 400s, 420s, 440s, 460s, 480s, 500s, 550s, 600s, 650s, 700s, 750s, 800s, 850s, 900s, 950s, 1000s, 1050s, 1100s, 1150s, 1200s, 1250s, 1300s, 1350s, 1400s, 1450s, 1500s, 1550s, 1600s, 1650s, 1700s, 1750s, or 1800s, etc.

[0035] As a preferred technical solution for the preparation method of the electrocatalytic hydrogen evolution electrode of the present invention, the calcination temperature in step (3) is 300℃~600℃, for example, it can be 300℃, 325℃, 350℃, 400℃, 450℃, 500℃, 550℃ or 600℃, etc.

[0036] Preferably, the heating rate of the calcination in step (3) is 1℃ / min to 5℃ / min, for example, it can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min or 5℃ / min, etc.

[0037] Preferably, the calcination holding time in step (3) is 1h to 6h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h or 6h.

[0038] Preferably, the calcination atmosphere in step (3) is a reducing atmosphere.

[0039] Preferably, the reducing atmosphere contains a protective gas and a reducing gas, and the volume percentage of the reducing gas is 3% to 10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.

[0040] Preferably, the protective gas includes at least one of helium, argon, or nitrogen.

[0041] Preferably, the reducing gas includes H2.

[0042] The present invention does not specifically limit the equipment used for calcination; for example, it can be a tube furnace.

[0043] As a preferred embodiment of the preparation method of the electrocatalytic hydrogen evolution electrode of the present invention, the preparation method includes the following steps:

[0044] (1) An electrodeposition solution is obtained by adding soluble nickel salt, soluble iron salt and soluble rare earth salt to deionized water and dissolving them. The mass concentration of nickel salt in the electrodeposition solution is 15 g / L to 25 g / L, the mass concentration of iron salt in the electrodeposition solution is 5 g / L to 15 g / L, and the mass concentration of rare earth salt in the electrodeposition solution is 1 g / L to 9 g / L.

[0045] (2) Using the pretreated nickel foam as the cathode and the platinum sheet as the anode, the electrodeposition method is adopted with a voltage of -0.5V to -1.5V. Electrodeposition is carried out in the electrodeposition solution for 400s to 1800s, thereby obtaining the NiFe-LDH / RE(OH)3 precursor layer on the surface of the nickel foam, wherein RE is a rare earth element.

[0046] (3) After drying, the nickel foam loaded with NiFe-LDH / RE(OH)3 precursor layer is transferred to a tube furnace and calcined in a reducing atmosphere to obtain the electrocatalytic hydrogen evolution electrode. The reducing atmosphere consists of a mixture of H2 and Ar, with the volume percentage of H2 in the mixture being 3% to 10%. The calcination temperature is 300℃ to 600℃, and the calcination holding time is 1h to 6h.

[0047] Thirdly, the present invention provides an application of the electrocatalytic hydrogen evolution electrode as described in the first aspect, wherein the electrocatalytic hydrogen evolution electrode is used in the field of electrocatalytic hydrogen evolution.

[0048] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0049] Compared with existing technologies, the present invention has the following beneficial effects:

[0050] (1) In the rare earth oxide-based electrocatalytic material provided by the present invention, the unique 4f electrons of RE2O3 regulate the electronic structure of FeNi3, optimize the adsorption energy barrier of proton hydrogen on the catalyst surface, regulate the adsorption state of hydrogen evolution intermediate on the catalyst surface, accelerate the reaction kinetics of the catalyst, and enable the catalyst to exhibit satisfactory electrocatalytic hydrogen evolution activity in alkaline medium.

[0051] (2) The preparation method of the present invention is simple, fast and efficient, and the chemical reagents used are inexpensive. The preparation method has the economical preparation cost and the feasibility of industrial application, and has great application prospects in the field of industrial water electrolysis. Attached Figure Description

[0052] Figure 1 X-ray diffraction (XRD) patterns of hydrogen evolution electrodes in Examples 1-4 and the comparative examples;

[0053] Figure 2 The XRD pattern of the sample loaded on carbon cloth using the same method as in Example 2;

[0054] Figure 3 The full X-ray photoelectron spectroscopy (XPS) spectra of the hydrogen evolution electrodes of Examples 1-4 and the comparative examples are shown.

[0055] Figure 4 This is a scanning electron microscope image of the hydrogen evolution electrode in Example 1;

[0056] Figure 5 This is a scanning electron microscope image of the hydrogen evolution electrode in Example 2;

[0057] Figure 6 This is a scanning electron microscope image of the hydrogen evolution electrode in Example 3;

[0058] Figure 7 This is a scanning electron microscope image of the hydrogen evolution electrode in Example 4;

[0059] Figure 8 This is a scanning electron microscope image of the hydrogen evolution electrode for comparison.

[0060] Figure 9 Linear sweep voltammetry (LSV) curves of hydrogen evolution electrodes prepared in Examples 1-4 and comparative examples;

[0061] Figure 10 Tafel curves of hydrogen evolution electrodes prepared in Examples 1-4 and comparative examples;

[0062] Figure 11 The 30-hour constant voltage electrolysis curve of the hydrogen evolution electrode prepared in Example 2;

[0063] Figure 12This is a comparison of linear sweep voltammetry curves before and after stability testing of the hydrogen evolution electrode prepared in Example 2.

[0064] Figure 13 This is a scanning electron microscope image of the hydrogen evolution electrode prepared in Example 2 after stability testing.

[0065] Figure 14 The CV curves of the hydrogen evolution electrodes of Examples 1-4 and the comparative examples at scan rates of 20 mV / s, 40 mV / s, 60 mV / s, 80 mV / s, and 100 mV / s are shown.

[0066] Figure 15 The double-layer capacitance (C) of the hydrogen evolution electrodes in Examples 1-4 and the comparative examples dl );

[0067] Figure 16 Electrochemical impedance spectroscopy (EIS) of the hydrogen evolution electrodes in Examples 1-4 and the comparative examples;

[0068] Figure 17 The fine XPS spectra of Ni 2p and Fe 2p are for Example 2 and the comparative example. Detailed Implementation

[0069] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0070] The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0071] Example 1

[0072] This embodiment provides a rare earth oxide-based electrocatalytic material, which includes FeNi3 / Pr2O3, wherein the molar ratio of Fe to Pr is 1:0.04.

[0073] This embodiment also provides an electrocatalytic hydrogen evolution electrode, which includes a conductive substrate and a catalyst layer supported on the surface of the conductive substrate. The catalyst in the catalyst layer is the rare earth oxide-based electrocatalytic material mentioned above, wherein the conductive substrate is nickel foam (abbreviated as NF).

[0074] The preparation method of the electrocatalytic hydrogen evolution electrode provided in this embodiment includes the following steps:

[0075] This embodiment provides a method for preparing an electrocatalytic hydrogen evolution catalyst, including the following steps:

[0076] (1) Weigh 3.75 mmol nickel nitrate, 1.25 mmol ferric nitrate and 0.05 mmol praseodymium nitrate, dissolve them in 50 mL deionized water, stir well to obtain electrodeposition solution;

[0077] (2) A nickel foam that has been sonicated for 15 minutes with acetone, 30 minutes with HCl, 15 minutes with deionized water, and 15 minutes with anhydrous ethanol and then vacuum dried was used as the cathode and a platinum sheet as the anode. Electrodeposition was carried out in the electrodeposition solution of step (1) using the electrodeposition method. During the electrodeposition process, the voltage was -1V and the electrodeposition time was 600s. A NiFe-LDH / Pr(OH)3 precursor layer was obtained on the surface of the nickel foam.

[0078] (3) After electrodeposition, the electrode is removed and washed. After vacuum drying at 60°C overnight, the nickel foam loaded with the precursor layer is placed in a tube furnace and heated to 500°C at a heating rate of 5°C / min in a reducing atmosphere (composed of a mixture of H2 and Ar, with a volume percentage of H2 of 5%). The temperature is held for 2 hours to obtain the electrocatalytic hydrogen evolution electrode, which is simply referred to as the FeNi3 / Pr2O3 / NF electrocatalytic hydrogen evolution electrode.

[0079] Example 2

[0080] This embodiment provides a rare earth oxide-based electrocatalytic material, which differs from Embodiment 1 in that the molar ratio of Fe to Pr is 1:0.4.

[0081] This embodiment provides an electrocatalytic hydrogen evolution electrode, which includes a conductive substrate and a catalyst layer supported on the surface of the conductive substrate. The catalyst in the catalyst layer is the rare earth oxide-based electrocatalytic material mentioned above, and the conductive substrate is nickel foam.

[0082] This embodiment provides a method for preparing an electrocatalytic hydrogen evolution electrode. The difference from Example 1 is that the molar amount of praseodymium nitrate in step (1) is 0.5 mmol, while the rest is the same as in Example 1.

[0083] Example 3

[0084] This embodiment provides a rare earth oxide-based electrocatalytic material, which differs from Embodiment 1 in that the molar ratio of Fe to Pr is 1:1.2.

[0085] This embodiment provides an electrocatalytic hydrogen evolution electrode, which includes a conductive substrate and a catalyst layer supported on the surface of the conductive substrate. The catalyst in the catalyst layer is the rare earth oxide-based electrocatalytic material mentioned above, and the conductive substrate is nickel foam.

[0086] This embodiment provides a method for preparing an electrocatalytic hydrogen evolution electrode. The difference from Example 1 is that the molar amount of praseodymium nitrate in step (1) is 1.5 mmol, while the rest is the same as in Example 1.

[0087] Example 4

[0088] This embodiment provides a rare earth oxide-based electrocatalytic material, which differs from Embodiment 1 in that the molar ratio of Fe to Pr is 1:2.

[0089] This embodiment provides an electrocatalytic hydrogen evolution electrode, which includes a conductive substrate and a catalyst layer supported on the surface of the conductive substrate. The catalyst in the catalyst layer is the rare earth oxide-based electrocatalytic material mentioned above, and the conductive substrate is nickel foam.

[0090] This embodiment provides a method for preparing an electrocatalytic hydrogen evolution electrode. The difference from Example 1 is that the molar amount of praseodymium nitrate in step (1) is 2.5 mmol, while the rest is the same as in Example 1.

[0091] Comparative Example

[0092] This comparative example provides an electrocatalytic material FeNi3.

[0093] This comparative example provides an electrocatalytic hydrogen evolution electrode, which includes a conductive substrate and a catalyst layer supported on the surface of the conductive substrate. The catalyst in the catalyst layer is the aforementioned electrocatalytic material, wherein the conductive substrate is nickel foam.

[0094] This comparative example provides a method for preparing an electrocatalytic hydrogen evolution electrode. The difference from Example 1 is that praseodymium nitrate is not added in step (1), while all other steps are the same as in Example 1.

[0095] Performance testing:

[0096] (1) The hydrogen evolution electrodes prepared in Examples 1-4 and the comparative examples were analyzed using a D8 Advance X-ray diffractometer from Bruker AXS GmbH, Germany. Figure 1 It can be seen that in Examples 1 to 4, as the amount of Pr added increases, the intensity of the diffraction peak at approximately 31° gradually increases. Through analysis using Jade software, these peaks are attributed to the (-4 0 2) plane and (0 1 2) plane of monoclinic Pr2O3, indicating that under heating conditions, Pr(OH)3 in the precursor is converted into monoclinic Pr2O3.

[0097] Considering the excessively strong diffraction peaks of nickel foam and the similar diffraction peak positions of FeNi3 phase and nickel foam in Examples 1-4, which could adversely affect phase analysis, the same catalyst was loaded onto carbon cloth using the same method as in Example 2, and the tests were conducted using the same method. The results are as follows: Figure 2 As shown. By Figure 2It can be seen that, apart from the diffraction peak of carbon cloth, the diffraction peak at about 44° belongs to the (1 1 1) plane of the FeNi3 phase. Therefore, it can be concluded that NiFe-LDH is reduced to the FeNi3 metallic phase under a reducing atmosphere.

[0098] (2) The elemental composition of the hydrogen evolution electrodes prepared in Examples 1-4 and the comparative examples was analyzed using a Thermo Scientific K-Alpha+ X-ray photoelectron spectroscopy system manufactured by Thermo Fischer, USA. The results are as follows: Figure 3 As shown, by Figure 3 It can be seen that the presence of the 3d orbital peak of Pr can be clearly observed in Examples 2 to 4. In Example 1, due to the preparation process, the amount of praseodymium nitrate added to the precursor is relatively small, so the signal of the Pr 3d orbital peak is weak.

[0099] (3) The hydrogen evolution electrodes prepared in Examples 1-4 and the comparative examples were morphologically analyzed using a Carl Zeiss Sigma 300 scanning electron microscope. The results are as follows: Figures 4 to 8 As shown. By Figures 4 to 8 It can be seen that the morphology of Examples 1-4 and the comparative examples is similar, all of which are three-dimensional structures similar to coral, but the particle sizes that make up this structure are significantly different.

[0100] (4) To verify the electrocatalytic performance of the electrode material prepared in this invention, the inventors used an electrochemical workstation (CHI760E, Shanghai Chenhua) to study the electrocatalytic hydrogen evolution performance of the hydrogen evolution electrode, and used the prepared FeNi3-loaded nickel foam as a comparative example. All electrocatalytic tests were performed at room temperature, using 1M KOH as the electrolyte, and a standard three-electrode system (with the hydrogen evolution electrode as the working electrode, the nickel foam in the working electrode being 1cm×2cm in size, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode), with a scan rate of 5mV / s. The linear scan curves of hydrogen evolution for samples from Examples 1-4 and the comparative example were tested, and the results are as follows: Figure 9 As shown.

[0101] All test data were converted into a reversible hydrogen electrode, using the following formula:

[0102] E RHE =E Ag / AgCl +E0 Ag / AgCl +0.0592×pH

[0103] Where: E RHE E represents the reversible hydrogen overpotential (V). Ag / AgCl E0 represents the measured electrode potential (V). Ag / AgCl The standard electrode potential of the Ag / AgCl electrode is 0.197V.

[0104] The electrocatalytic hydrogen evolution electrodes prepared in Examples 1-4 and the comparative examples were subjected to electrocatalytic hydrogen evolution performance tests. The hydrogen evolution overpotentials (mV) obtained from the tests are shown in Table 1.

[0105] like Figure 9 As shown in the polarization curves in 1M KOH solution, Examples 1-4 and the comparative examples all exhibit low onset potentials. When the current density reaches 10 mA·cm⁻¹... -2 At that time, the overpotentials of Examples 1-4 and the comparative examples were 130 mV, 91 mV, 139 mV, 178 mV, and 174 mV, respectively. This indicates that the catalyst without Pr added during preparation showed poor hydrogen evolution activity in the comparative example, while the samples with added Pr exhibited better performance, especially the catalyst (Example 2) at 10 mA·cm⁻¹. -2 The voltage was only 91 mV, indicating that Pr element and its content are key factors affecting catalyst performance. When the current density reached 40 mA·cm⁻¹... -2 At that time, the overpotentials in Examples 1-4 were 241mV, 211mV, 259mV, and 301mV, respectively. The current density reached 60mA·cm. -2 At that time, the overpotentials of Examples 1 to 4 increased to 288mV, 265mV, 312mV and 357mV respectively. Example 2 always maintained the best catalytic activity. It can also be seen that the performance of the catalyst is not consistent with the content of Pr. It shows a phenomenon of first increasing and then decreasing with the content of Pr. This may be because the content of Pr is too high, which causes the accumulation of Pr2O3 and thus affects its electrocatalytic performance.

[0106] The Tafel slope obtained from the polarization curves of the various embodiments and comparative examples is as follows: Figure 10 As shown in Table 2, the specific values ​​of the Tafel slope for each embodiment and comparative example are given. Table 2 shows that the Tafel slope for Example 2 is only 87 mV dec. -1 The Tafel slopes of Examples 1-3 were significantly smaller than those of the other examples and the comparative example, indicating that Example 2 had faster reaction kinetics. Meanwhile, the Tafel slopes of Examples 1-3 were all smaller than those of the comparative example, suggesting that the introduction of an appropriate amount of rare earth oxides could significantly improve their reaction kinetics.

[0107] Figure 11 The 30-hour constant voltage electrolysis curve of the hydrogen evolution electrode prepared in Example 2 is shown below. Figure 11 It can be seen that Example 2 can be performed at 20mA·cm -2 It can be stably electrolyzed for about 30 hours at a current density without significant degradation.

[0108] Figure 12 This is a comparison of linear sweep voltammetry curves before and after the stability test of the hydrogen evolution electrode prepared in Example 2. Figure 12It can be seen that after 30 hours of stability testing, Example 2 showed good performance at 10 mA·cm⁻¹. -2 The overpotential did not change significantly at 100 mA·cm -2 The overpotential shifted negative by 13 mV, demonstrating good stability. This slight decay is almost negligible under alkaline conditions.

[0109] The microstructure of the catalyst after recycling was characterized by SEM, such as... Figure 13 As shown, the catalyst prepared in Example 2 was still uniformly loaded on the surface of the nickel foam support without significant peeling or detachment. It can also be seen that the microstructure of the catalyst did not change significantly compared with the sample before the stability test, which further illustrates the good stability of the catalyst.

[0110] The CV curves of the hydrogen evolution electrodes of Examples 1-4 and the comparative example were further tested at different scan rates, and the results are as follows: Figure 14 As shown, based on the CV curves at different scan rates, further... Figure 14 The double-layer capacitance (C) of Examples 1-4 and the comparative example was obtained. dl (See also) Figure 15 ), because C dl It is directly proportional to the electrochemical active area (ECSA), and is therefore often used to reflect changes in the ECSA of a catalyst. The ECSA of Examples 1-4 and the comparative examples are shown in Table 3. As can be seen from Table 3, Example 2 has the largest ECSA.

[0111] Figure 16 The electrochemical impedance spectroscopy (EIS) test results for Examples 1-4 and the comparative examples are provided by [the relevant authority / organization]. Figure 16 It can be seen that the charge transfer resistance in Example 2 decreased significantly, and was much lower than that in other examples and comparative examples. Therefore, the outstanding alkaline hydrogen evolution activity of Example 2 mainly comes from the introduction of an appropriate amount of Pr2O3 into the catalyst, which increases the number of active sites on the catalyst and reduces the resistance to charge migration.

[0112] To further explore the microscopic mechanism of enhanced activity in FeNi3 / Pr2O3 / NF, X-ray photoelectron spectroscopy was used to characterize the valence state changes of Ni and Fe in Example 2 and the comparative example. The results were obtained from... Figure 17 As shown, by Figure 17It can be seen that, compared with the comparative example, the binding energies of Ni and Fe in Example 2 shift towards lower energies. This is because the difference in electronegativity between Pr and Fe / Ni (Pr: 1.13; Fe: 1.8; Ni: 1.9) leads to charge rearrangement between Pr₂O₃ and FeNi₃. Pr₂O₃ acts as an "electron pump," keeping FeNi₃ in an electron-rich state, thereby modulating the reaction energy barrier of the hydrogen evolution process, optimizing the adsorption and desorption process of protonated hydrogen on the FeNi₃ surface, and achieving faster reaction kinetics. Figure 17 It can be clearly observed that Ni in Example 2 0 The content of Ni increased significantly compared to the comparative ratio. This is also due to the electron-donating effect of Pr2O3, which prevents the highly reactive metallic Ni from being oxidized to less reactive Ni. 2+ / Ni 3+ In addition, due to the oxophilic nature of rare earth elements, Pr₂O₃ can adsorb OH⁻ from aqueous solutions. - To prevent the active sites on FeNi3 from being destroyed by OH - Covering the catalyst surface and accelerating the dissociation of H2O helps alleviate the slow hydrogen evolution kinetics in alkaline media. A simple composite of FeNi3 and Pr2O3 achieves two goals at once: Pr2O3 optimizes the adsorption-desorption process of protonated hydrogen at active sites through an "electron pump" effect, and accelerates the dissociation of water molecules on the catalyst surface, thus resulting in a significantly enhanced electrocatalytic hydrogen evolution activity of FeNi3 / Pr2O3 / NF in alkaline media.

[0113] Table 1. Hydrogen evolution overpotentials (mV) of Examples 1-4 and Comparative Examples

[0114] Example 1 130 241 288 Example 2 91 211 265 Example 3 139 259 312 Example 4 178 301 357 Comparative Example 174 294 348

[0115] Table 2. Tafel slopes of Examples 1-4 and Comparative Examples.

[0116] Example 1 99 Example 2 87 Example 3 127 Example 4 132 Comparative Example 130

[0117] Table 3. Electrochemical active area (ECSA) of Examples 1-4 and Comparative Examples

[0118] Example 1 7.7 8.47 423.5 Example 2 19.4 21.34 1067 Example 3 6.6 6.76 338 Example 4 2.3 2.53 126.5 Comparative Example 3.5 3.85 192.5

[0119] C DL =C dl ×1.1cm 2 ECSA = C DL / Cs; Cs=0.02mF·cm -2

[0120] In summary, by introducing an appropriate amount of rare earth oxides into the catalyst, this invention can regulate the electronic structure of FeNi3, optimize the adsorption energy barrier of protonated hydrogen on the catalyst surface, regulate the adsorption state of hydrogen evolution intermediates on the catalyst surface, accelerate the reaction kinetics of the catalyst, and enable the catalyst to exhibit satisfactory electrocatalytic hydrogen evolution activity in alkaline media.

[0121] The applicant declares that the detailed method of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A rare earth oxide-based electrocatalytic material, characterized in that, The rare earth oxide-based electrocatalytic material includes FeNi3 / Pr2O3, wherein the molar ratio of Fe to Pr is 1:(0.04~1.2).

2. An electrocatalytic hydrogen evolution electrode, characterized by, The electrocatalytic hydrogen evolution electrode includes a conductive substrate and a catalyst layer supported on the surface of the conductive substrate, wherein the catalyst in the catalyst layer includes the rare earth oxide-based electrocatalytic material as described in claim 1.

3. The electrocatalytic hydrogen evolution electrode according to claim 2, wherein, The conductive substrate is nickel foam.

4. A method for producing an electrocatalytic hydrogen evolution electrode as claimed in claim 2 or 3, characterized in that The preparation method includes the following steps: (1) An electrodeposition solution was prepared using nickel source, iron source and rare earth source; (2) Using a conductive substrate as the cathode, electrodeposition is performed in the electrodeposition solution to obtain a NiFe-LDH / RE(OH)3 precursor layer on the surface of the conductive substrate. (3) The conductive substrate loaded with NiFe-LDH / RE(OH)3 precursor layer is calcined to obtain the electrocatalytic hydrogen evolution electrode.

5. The method of claim 4, wherein the method further comprises the step of: The nickel source in step (1) is a water-soluble nickel salt.

6. The method of claim 5, wherein the method further comprises: The water-soluble nickel salt includes nickel nitrate.

7. The method of claim 4, wherein the method further comprises the step of: The mass concentration of the nickel source in the electrodeposition solution in step (1) is 15 g / L to 25 g / L.

8. The method of claim 4, wherein the method further comprises the step of: The iron source in step (1) is a water-soluble iron salt.

9. The method of claim 8, wherein the method further comprises the step of: The water-soluble iron salts include ferric nitrate.

10. The method of claim 4, wherein the method further comprises the step of: The mass concentration of the iron source in the electrodeposition solution in step (1) is 5 g / L to 15 g / L.

11. The method of claim 4, wherein the method further comprises the step of: The rare earth source in step (1) is a water-soluble rare earth salt.

12. The method of claim 11, wherein the method further comprises: The water-soluble rare earth salts include praseodymium nitrate.

13. The method of claim 4, wherein the method further comprises the step of: The mass concentration of the rare earth source in the electrodeposition solution in step (1) is 1 g / L to 10 g / L.

14. The method of claim 4, wherein the method is characterized by: The solvent in the electrodeposition solution in step (1) is water.

15. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, In the electrodeposition process described in step (2), a platinum sheet is used as the anode.

16. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The conductive substrate is nickel foam.

17. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 16, characterized in that, The nickel foam is pretreated before use.

18. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 17, characterized in that, The pretreatment involves sequentially applying acetone, HCl, water, and ethanol to an ultrasonic treatment solution.

19. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, During the electrodeposition process described in step (2), the voltage is -0.5V to -1.5V.

20. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The electrodeposition time in step (2) is 400s to 1800s.

21. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The calcination temperature in step (3) is 300℃~600℃.

22. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The heating rate of calcination in step (3) is 1℃ / min to 5℃ / min.

23. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The calcination holding time in step (3) is 1h to 6h.

24. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The calcination atmosphere in step (3) is a reducing atmosphere.

25. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 24, characterized in that, The reducing atmosphere contains a protective gas and a reducing gas, wherein the volume percentage of the reducing gas is 3% to 10%.

26. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 25, characterized in that, The protective gas includes at least one of helium, argon, or nitrogen.

27. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 25, characterized in that, The reducing gas includes H2.

28. The method for preparing the electrocatalytic hydrogen evolution electrode according to claim 4, characterized in that, The preparation method includes the following steps: (1) An electrodeposition solution is obtained by adding soluble nickel salt, soluble iron salt and soluble rare earth salt to deionized water and dissolving them. The mass concentration of nickel salt in the electrodeposition solution is 15~25 g / L, the mass concentration of iron salt in the electrodeposition solution is 5~15 g / L and the mass concentration of rare earth salt in the electrodeposition solution is 1~9 g / L. (2) Using the pretreated nickel foam as the cathode and the platinum sheet as the anode, the electrodeposition method is adopted with a voltage of -0.5~-1.5V. Electrodeposition is carried out in the electrodeposition solution for 400s~1800s, and then a NiFe-LDH / RE(OH)3 precursor layer is obtained on the surface of the nickel foam, wherein RE is a rare earth element; (3) After drying the nickel foam loaded with NiFe-LDH / RE(OH)3 precursor layer, transfer it to a tube furnace and calcine it under a reducing atmosphere to obtain the electrocatalytic hydrogen evolution electrode; wherein, the reducing atmosphere is composed of a mixture of H2 and Ar, the volume percentage of H2 in the mixture is 3%~10%, the calcination temperature is 300℃~600℃, and the calcination holding time is 1h~6h.

29. Use of an electrocatalytic hydrogen evolution electrode as described in claim 2 or 3, characterized in that, The electrocatalytic hydrogen evolution electrode is used in the field of electrocatalytic hydrogen evolution.

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