Nickel oxide-based iron-iridium double electrodeposition catalyst as well as preparation method and application thereof

Abstract

The invention discloses a nickel oxide-based iron-iridium double-electrodeposition catalyst and a preparation method and application thereof, and belongs to the technical field of catalytic materials.A nickel oxide material is prepared into a nickel oxide working electrode, a mixed solution of an iron precursor, an iridium precursor and an OH <-> source serves as electrolyte, and the nickel oxide-based iron-iridium double-electrodeposition catalyst is obtained through electrochemical deposition. And depositing iron-iridium bimetal on the nickel oxide working electrode to obtain the nickel oxide-based iron-iridium double electrodeposition catalyst. According to the preparation method provided by the invention, multi-scale dispersion of two metal elements of iron and iridium on the surface of the nickel oxide carrier is realized, and the multi-scale structure not only provides abundant catalytic active sites, so that the catalyst can more efficiently adsorb and activate reactants in the reaction process, but also obviously enhances the transfer efficiency of electrons, so that the catalytic activity of the catalyst is improved. Therefore, the catalytic activity of the catalyst is improved. In addition, the electronic structure of the catalyst is optimized through the synergistic effect of iron and iridium, and the catalytic performance of the catalyst is further improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a nickel oxide-based iron-iridium dual electrodeposition catalyst and a preparation method and application thereof. Background Art

[0002] Hydrogen production by water electrolysis is an efficient and clean energy conversion technology that can convert electrical energy into chemical energy, providing important support for achieving a carbon-neutral energy structure transformation. The oxygen evolution reaction, referred to as OER, is an anode reaction in the water electrolysis process, involving the generation of oxygen, and is a key step in achieving efficient water electrolysis. Efficient and stable electrocatalysts are the key to achieving large-scale application of OER technology because they can significantly reduce the overpotential of the reaction and increase the reaction rate and stability. Nickel-based materials exhibit unique dynamic structural changes in the water electrolysis reaction due to their lattice oxygen mechanism, which can form a surface rich in oxygen vacancies and active sites. At the same time, they have good conductivity, stability and low cost, making them ideal carriers for constructing efficient electrocatalysts.

[0003] In electrocatalytic reactions, the electronic structure and geometry of the catalytic interface significantly influence catalytic activity and selectivity. Current chemical synthesis methods face numerous challenges in preparing these multi-scale catalytic interfaces. Conventional chemical synthesis methods struggle to achieve continuous control of the catalytic interface size, resulting in complex reaction conditions, insufficient reactive sites on the resulting catalysts, and poor catalytic performance and stability. The high surface energy of metal species leads to the aggregation of metal sites, which in turn hinders efficient charge transfer and reduces catalytic efficiency. Summary of the Invention

[0004] The present invention provides a nickel oxide-based iron-iridium dual electrodeposition catalyst and its preparation method and application, which effectively solves the technical problems that the catalyst prepared by the existing synthesis method has insufficient reaction active sites, resulting in poor catalytic performance and stability; the aggregation of metal sites affects the effective transfer of charge, thereby reducing the catalytic efficiency. At the same time, it provides a nickel oxide-based iron-iridium dual electrodeposition catalyst with high catalytic activity and excellent catalytic stability.

[0005] The first object of the present invention is to provide a method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst, comprising the following steps: Using DL-α-alanine as ligand, Ni 2+ The source forms a Ni-alanine complex, which is pyrolyzed at 550°C to 620°C in an air atmosphere to decompose the complex in the Ni-alanine complex to obtain a nickel oxide material.

[0006] The nickel oxide material is prepared as a nickel oxide working electrode using an iron precursor, an iridium precursor and OH －The mixed solution of the source is an electrolyte, and the iron-iridium bimetallic is deposited on the nickel oxide working electrode by electrochemical deposition to obtain a nickel oxide-based iron-iridium bimetallic electrochemical deposition catalyst.

[0007] In the electrolyte, the molar ratio of the iridium precursor to the iron precursor is 1:0.2~2.

[0008] As a preferred embodiment, in the electrolyte, the molar ratio of the iridium precursor to the iron precursor is 1:1.

[0009] As a preferred embodiment, the electrochemical deposition adopts chronoamperometry, the voltage is 5V to 7V, and the electrochemical deposition time is 8000s to 12000s. More preferably, the electrochemical deposition adopts chronoamperometry, the voltage is 6V, and the electrochemical deposition time is 10000s.

[0010] As a preferred embodiment, before electrochemical deposition, the nickel oxide working electrode is electrochemically activated, specifically by using a standard three-electrode － A short pulse of a cathode potential of -2 V to -1.5 V for 0.5 s to 1.5 s and a short pulse of an anode potential of 1.5 V to 2 V for 0.5 s to 1.5 s are sequentially applied to the nickel oxide working electrode in a solution of . More preferably, a short pulse of a cathode potential of -2 V for 1 s and a short pulse of an anode potential of 2 V for 1 s are sequentially applied to the nickel oxide working electrode.

[0011] As a preferred embodiment, one short pulse of cathode potential and one short pulse of anode potential is considered as one cycle, and the cycle is repeated 40 to 60 times, more preferably 50 times.

[0012] As a preferred embodiment, the preparation method of the nickel oxide working electrode is: ultrasonically mixing the nickel oxide material, ethanol and Nafion, and drop-coating the mixture on carbon paper to obtain a nickel oxide material with a loading of 0.8 mg / cm 2 ~2.3mg / cm 2 More preferably, the nickel oxide material, ethanol and Nafion are ultrasonically mixed and drop-coated on carbon paper to obtain a nickel oxide material with a loading of 1 mg / cm 2 nickel oxide working electrode.

[0013] As a preferred embodiment, the Ni 2+ The molar ratio of the source to DL-α-alanine is 1:4~5.

[0014] As a preferred embodiment, the pyrolysis time is 1.5 h to 3 h. More preferably, the pyrolysis time is 2 h.

[0015] The second object of the present invention is to provide a nickel oxide-based iron-iridium dual electrodeposition catalyst prepared by any of the preparation methods described above.

[0016] The third object of the present invention is to provide an application of the above nickel oxide-based iron-iridium dual electrodeposition catalyst in catalytic electrolysis of water.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing a nickel oxide-based iron-iridium double electrodeposition catalyst, wherein DL-α-alanine is used as a ligand and Ni 2+ The nickel-alanine complex is formed by heating the Ni-alanine complex to 550°C to 620°C in an air atmosphere to be pyrolyzed, and the complex in the Ni-alanine complex is decomposed to obtain a nickel oxide material; the nickel oxide material is prepared as a nickel oxide working electrode, and an iron precursor, an iridium precursor and an OH group are used. - The mixed solution of the source is an electrolyte, and an iron-iridium bimetallic is deposited on the nickel oxide working electrode by electrochemical deposition to obtain a nickel oxide-based iron-iridium dual-electrodeposition catalyst. The preparation method provided by the present invention realizes the multi-scale dispersion of the two metal elements of iron and iridium on the surface of the nickel oxide support. By adjusting the amount of the iron precursor and the iridium precursor, the multi-scale construction of different metal catalytic interfaces can be achieved. This multi-scale structure not only provides abundant catalytic active sites, allowing the catalyst to more efficiently adsorb and activate reactants during the reaction, but also significantly enhances the electron transfer efficiency, thereby improving the catalytic activity of the catalyst. In addition, the synergistic effect of iron and iridium optimizes the electronic structure of the catalyst, further improving its catalytic performance.

[0018] The nickel oxide-based iron-iridium dual electrodeposition catalyst provided by the present invention has a high specific surface area. This is due to the surface defects introduced by applying pulses to the nickel oxide. These defects promote the formation of a rich porous structure on the nickel oxide support. This porous structure not only increases the specific surface area of ​​the catalyst but also significantly enhances its adsorption capacity for reactants, thereby improving catalytic activity. In addition, the coordination environment of iron and iridium allows for efficient charge transfer, which enables the catalyst to optimize its electronic structure, thereby showing higher efficiency and stability in electrocatalytic reactions.

[0019] The preparation method of the nickel oxide-based iron-iridium dual electrodeposition catalyst provided by the present invention adjusts the form of metal deposition on nickel oxide by controlling the concentration of metal precursors and the electrochemical deposition time, thereby preparing a multi-scale deposition catalytic interface from isolated single atoms, atomic clusters to nanoparticles.

[0020] The preparation method of the present invention is universally applicable to a variety of metal elements and can achieve precise control of the catalytic interface dimensions through precise regulation of electrochemical deposition conditions. Therefore, the catalyst prepared by the present invention can promote activities related to electrocatalytic water splitting, thereby improving the catalytic activity of the catalyst. Furthermore, the preparation method of the present invention is simple to operate, requires minimal equipment, and the operation process is highly controllable, which can further improve the catalyst output ratio, making it very suitable for large-scale production and of great value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are spherical aberration-corrected high-angle annular dark-field scanning transmission electron micrographs of the nickel oxide-based iron-iridium dual electrodeposition catalyst prepared in Example 1 of the present invention, wherein (a) is 50 nm, (b) is 500 nm, (c) is the distribution diagram of the Ir element, (d) is the distribution diagram of the O element, and (e) is the distribution diagram of the Ni element.

[0022] Figure 2 The linear sweep voltammetric curves of the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention for OER reaction, wherein NiO x For comparative example 1, NiO x -Fe is comparative example 2, NiO x -Ir is comparative example 3, NiO x -IrFe is Example 1, NiO x -IrFe 0.2 For Example 2, NiO x -IrFe2 is Example 3.

[0023] Figure 3 The catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention were tested at 10 mA·cm -2 The overpotential diagram required for the OER reaction of electrocatalytic water decomposition under low temperature, where NiO x For comparative example 1, NiO x -Fe is comparative example 2, NiO x -Ir is comparative example 3, NiO x -IrFe is Example 1, NiO x -IrFe 0.2 This is Example 2.

[0024] Figure 4 The Tafel slope diagram of the OER reaction of the electrocatalytic water decomposition of the catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention, wherein NiO x For comparative example 1, NiO x -Fe is comparative example 2, NiO x-Ir is comparative example 3, NiO x -IrFe is Example 1, NiO x -IrFe 0.2 This is Example 2.

[0025] Figure 5 The electrochemical active surface area diagram of the catalyst prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention for electrocatalytic water decomposition to generate OER reaction is obtained by cyclic voltammetry, wherein NiO x For comparative example 1, NiO x -Fe is comparative example 2, NiO x -Ir is comparative example 3, NiO x -IrFe is Example 1, NiO x -IrFe 0.2 This is Example 2.

[0026] Figure 6 The catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention were tested at 10 mA·cm -2 The stability test diagram of the OER reaction of electrocatalytic water splitting is shown below, where NiO x For comparative example 1, NiO x -Fe is comparative example 2, NiO x -Ir is comparative example 3, NiO x -IrFe is Example 1, NiO x -IrFe 0.2 This is Example 2. DETAILED DESCRIPTION

[0027] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention is further described below with reference to specific examples, but the examples are not intended to limit the present invention. The following experimental and detection methods are conventional methods unless otherwise specified; the reagents and raw materials are commercially available unless otherwise specified.

[0028] Existing catalyst chemical synthesis methods struggle to achieve continuous control of catalytic interface dimensions, resulting in complex reaction conditions, insufficient reactive sites, and poor catalytic performance and stability. The high surface energy of metal species leads to the aggregation of metal sites, hindering effective charge transfer and thus reducing catalytic efficiency. To address these technical issues, the present invention provides a nickel oxide-based iron-iridium dual electrodeposition catalyst, its preparation method, and its application.

[0029] The technical solution of the present invention is described in detail below.

[0030] The present invention provides a method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst, comprising the following steps: S1, with DL-α-alanine as ligand, and Ni 2+ The source forms a Ni-alanine complex, which is pyrolyzed at 550°C to 620°C in an air atmosphere to decompose the complex in the Ni-alanine complex to obtain a nickel oxide material.

[0031] S2, preparing the nickel oxide material as a nickel oxide working electrode with an iron precursor, an iridium precursor and OH - The mixed solution of the source is an electrolyte, and the iron-iridium bimetallic is deposited on the nickel oxide working electrode by electrochemical deposition to obtain a nickel oxide-based iron-iridium bimetallic electrochemical deposition catalyst.

[0032] In the electrolyte, the molar ratio of the iridium precursor to the iron precursor is 1:0.2~2.

[0033] In the above technical solution, an iron-iridium bimetallic compound is deposited on the nickel oxide working electrode by electrochemical deposition. By adjusting the amount of the iron precursor and the iridium precursor, a multi-scale construction of different metal catalytic interfaces can be achieved. This multi-scale structure not only provides abundant catalytic active sites, allowing the catalyst to more efficiently adsorb and activate reactants during the reaction, but also significantly enhances the electron transfer efficiency, thereby improving the catalytic activity of the catalyst. In addition, the coordination environment of iron and iridium allows for efficient charge transfer, which enables the catalyst to optimize its electronic structure, thereby showing higher efficiency and stability in the electrocatalytic reaction, further improving its catalytic performance.

[0034] Regarding the molar ratio of the iridium precursor to the iron precursor mentioned above, when the molar ratio of the iridium precursor to the iron precursor is within the range of 1:0.2 to 2, the improved catalyst performance stems from a synergistic effect between the two. When the molar ratio of the iron precursor is less than 0.2, the iron content is insufficient, making it difficult to form an effective two-site synergy, resulting in limited improvement in catalytic activity and insignificant improvement in stability. The iron only partially modifies the electronic structure of the iridium. When the molar ratio of the iron precursor exceeds 2, the excess iron forms an oxide film that covers the active sites, reducing the exposed area, hindering the dispersion of the iridium, altering the reaction pathway, weakening the dominant role of the iridium, and leading to a decrease in catalytic efficiency. Only within the range of 1:0.2 to 2 can the improved stability of iron and the contribution of iridium to activity be balanced, allowing the catalyst to achieve optimal overpotential and stability.

[0035] In order to further improve the catalytic performance of the catalyst, the molar ratio of the iron precursor to the iridium precursor in the electrolyte is 1:1. The molar ratio of 1:1 is achieved by optimizing the Ni 3+concentration, metal coordination environment and interface scale, to achieve a synergistic improvement in catalytic activity, kinetics and stability. However, when the molar ratio is 1:0.2 or 1:2, the synergistic effect is slightly unbalanced due to the deficiency or excess of a single component, and the performance is inferior.

[0036] In order to balance the activity and stability of the catalyst, the electrochemical deposition adopts the chronoamperometry, the voltage is 5V~7V, and the time of electrochemical deposition is 8000s~12000s. More preferably, the electrochemical deposition adopts the chronoamperometry, the voltage is 6V, and the time of electrochemical deposition is 10000s. In electrochemical deposition, voltage and time are the core parameters for regulating the catalytic interface. If the voltage is lower than 5V and the deposition time is less than 8000s, the driving force for metal ion reduction is insufficient, the deposition amount is significantly reduced, the active site density is low, it is easy to exist in the form of single atoms, there is a lack of cluster / nanoparticle synergy, the metal-support interaction is weak, and the stability is poor. When the voltage is higher than 7V and the deposition time is greater than 12000s, the metal ions are reduced too quickly, and it is easy to agglomerate to form nanoparticles covering the active sites, the defect structure of the support is destroyed, and Ni 3+ As the concentration decreases, side reactions intensify, and the catalyst activity and stability deteriorate simultaneously.

[0037] In order to achieve multi-scale catalytic interface control, the nickel oxide working electrode was electrochemically activated before electrochemical deposition, specifically: a standard three-electrode was used to － In a solution of , a short pulse of cathode potential of -2V to -1.5V for 0.5s to 1.5s and a short pulse of anode potential of 1.5V to 2V for 0.5s to 1.5s are sequentially applied to the nickel oxide working electrode. More preferably, a short pulse of cathode potential of -2V for 1s and a short pulse of anode potential of 2V for 1s are sequentially applied to the nickel oxide working electrode. Pulse activation is performed by electrochemical reconstruction on NiO x The introduction of a high density of defects and active sites on the surface lays the foundation for uniform metal deposition and strong MSI formation, a key prerequisite for achieving multi-scale catalytic interface control. Deviations from this parameter range can lead to insufficient defects or damage to the support structure, which in turn affects the quality of metal deposition and catalytic performance.

[0038] As a preferred embodiment, one short pulse of cathode potential and one short pulse of anode potential is considered as one cycle, and the cycle is repeated 40 to 60 times. More preferably, the cycle is repeated 50 times. If the number of repetitions is less than 40 times, the NiO x The surface will create defect structures. This will cause surface oxygen vacancies, N 3+The small number of active sites is not conducive to the subsequent anchoring of metal atoms, resulting in insufficient metal deposition and uneven dispersion, low density of catalyst active sites, and limited improvement in catalytic performance. When the number of repetitions is greater than 60 times, excessive pulse activation will cause the NiO x Damage to the lattice structure will cause the lattice to collapse, affecting the conductivity and stability of the carrier. It will also lead to excessive generation of surface defects, which will destroy the interface structure and make the uniformity of metal deposition worse, thereby adversely affecting the activity and stability of the catalyst.

[0039] As a preferred embodiment, the preparation method of the nickel oxide working electrode is: ultrasonically mixing the nickel oxide material, ethanol and Nafion, and drop-coating the mixture on carbon paper to obtain a nickel oxide material with a loading of 0.8 mg / cm 2 ~2.3mg / cm 2 More preferably, the nickel oxide material, ethanol and Nafion are ultrasonically mixed and drop-coated on carbon paper to obtain a nickel oxide material with a loading of 1 mg / cm 2 The nickel oxide working electrode. When the loading amount is 1mg / cm 2 When NiO x Evenly distributed on the surface of carbon paper, it ensures sufficient active sites, such as Ni 3+ , oxygen vacancies, participate in the electrocatalytic reaction, avoid ion diffusion obstruction or agglomeration coverage sites due to excessive loading, and facilitate experimental repeatability.

[0040] As a preferred embodiment, the Ni 2+ The molar ratio of the source to DL-α-alanine is 1:4~5. When preparing the complex, if the amount of DL-α-alanine is insufficient, that is, less than 4 as defined herein, the nickel ion coordination is unsaturated, and NiO x Few lattice defects, Ni 3+ The proportion is low, the *OH adsorption capacity is weak, the OER overpotential increases, and the metal deposition is easy to agglomerate. If the molar ratio of DL-α-alanine is greater than 5 defined here, the alanine is excessive, and the residual carbon after calcination covers the NiO x The surface conductivity decreases, the OER overpotential increases, the stability decreases, and the uniformity of electrochemical deposition is destroyed. This range can balance the coordination saturation and defect control to achieve performance optimization.

[0041] As a preferred embodiment, the pyrolysis time is 1.5h~3h. More preferably, the pyrolysis time is 2h. If the pyrolysis time is less than 1.5h, the Ni-alanine complex is not fully decomposed, and the organic ligand remains, resulting in NiO x The crystal transformation is incomplete. If the pyrolysis time is greater than 3h, NiO xThe grains grow excessively, the specific surface area decreases, and the catalyst activity and stability are significantly reduced.

[0042] The present invention will be described in detail below through the following examples and comparative examples.

[0043] Example 1 A method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min into powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0044] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x Powder loading is 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0045] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiO x The electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0046] S4, a mixed solution containing 1M potassium hydroxide, 100µM Fe(NO3)3·9H2O and 100µM IrCl4·xH2O was prepared as an electrolyte, and electrochemical deposition was performed on the activated nickel oxide working electrode at a voltage of 6V for 10000s to obtain a nickel oxide-based iron-iridium dual electrodeposition catalyst, which was recorded as NiO x -IrFe.

[0047] Example 2 A method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min to powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0048] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x The powder loading was 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0049] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiO xThe electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0050] S4, a mixed solution containing 1M potassium hydroxide, 20µM Fe(NO3)3·9H2O and 100µM IrCl4·xH2O was prepared as an electrolyte, and electrochemical deposition was performed on the activated nickel oxide working electrode at a voltage of 6V for 10000s to obtain a nickel oxide-based iron-iridium dual electrodeposition catalyst, which was recorded as NiO x -IrFe 0.2 .

[0051] Example 3 A method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min into powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0052] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x Powder loading is 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0053] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiO x The electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0054] S4, a mixed solution containing 1M potassium hydroxide, 200µM Fe(NO3)3·9H2O and 100µM IrCl4·xH2O was prepared as an electrolyte, and the activated nickel oxide working electrode was subjected to electrochemical deposition at a voltage of 6V for 10000s to obtain a nickel oxide-based iron-iridium dual electrodeposition catalyst, which was recorded as NiO x -IrFe2.

[0055] Example 4 A method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min into powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0056] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. xPowder loading is 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0057] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiO x The electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0058] S4, preparing a mixed solution containing 1M potassium hydroxide, 40µM Fe(NO3)3·9H2O and 100µM IrCl4·xH2O as an electrolyte, and performing electrochemical deposition on the activated nickel oxide working electrode at a voltage of 6V for 10,000s to obtain a nickel oxide-based iron-iridium dual electrodeposition catalyst.

[0059] Example 5 A method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min to powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0060] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO xThe powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x Powder loading is 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0061] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiO x The electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0062] S4, preparing a mixed solution containing 1M potassium hydroxide, 80µM Fe(NO3)3·9H2O and 100µM IrCl4·xH2O as an electrolyte, and performing electrochemical deposition on the activated nickel oxide working electrode at a voltage of 6V for 10,000s to obtain a nickel oxide-based iron-iridium dual electrodeposition catalyst.

[0063] In order to further illustrate the technical effects of the present invention, the present invention also provides a comparative example, which is as follows: Comparative Example 1 A method for preparing a nickel oxide catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min into powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO xpowder.

[0064] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x Powder loading is 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet, namely nickel oxide catalyst.

[0065] Comparative Example 2 A method for preparing a nickel oxide-based iron electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min to powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0066] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x Powder loading is 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0067] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiOx The electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0068] S4, a mixed solution containing 1M potassium hydroxide and 100µM Fe(NO3)3·9H2O was prepared as an electrolyte, and the activated nickel oxide working electrode was subjected to electrochemical deposition for 10000s at a voltage of 6V to obtain a nickel oxide-based iron electrodeposition catalyst, which was recorded as NiO x -Fe.

[0069] Comparative Example 3 A method for preparing a nickel oxide-based iridium electrodeposition catalyst comprises the following steps: S1, according to the molar ratio of nickel acetate tetrahydrate to DL-α-alanine 1:4.5, weigh 2.5 mmol, i.e., 0.622 g Ni(CH3COO)2·4H2O and 11.2 mmol, i.e., 89.09 g DL-α-alanine in a beaker, pour in 10 mL of deionized water, stir at 750 rpm for 10 min, pour in 140 mL of anhydrous ethanol, continue stirring at 750 rpm for 5 min to form a blue suspension, centrifuge, and wash the solid twice with deionized water and twice with ethanol. Collect the sediment and dry it overnight in an air environment at 60°C. After drying, cool it naturally to room temperature, take out the dried sample, grind it in an agate grinding mortar for 15 min into powder, put it into a quartz boat, and then place it in a tube furnace at a flow rate of 200 mL·min -1 In air atmosphere, at 1℃·min -1 The temperature was raised to 600 °C at a constant rate, maintained at this temperature for 2 h, and then cooled naturally to obtain nickel oxide material, which was recorded as NiO x powder.

[0070] S2, according to 1mg:200µL:10µL, weigh 0.25mgNiO x The powder, 50µL anhydrous ethanol and 2.5µL Nafion were mixed in a centrifuge tube and dispersed evenly by ultrasonication for 0.75h. The mixture was then evenly applied on a 0.5cm×0.5cm carbon paper with a microporous carbon layer using a pipette and allowed to dry overnight in air to obtain NiO. x The powder loading was 1.0 mg cm -2 The nickel oxide working electrode is denoted as NiO x Electrode sheet.

[0071] S3, using a standard three-electrode system, with a carbon rod as the counter electrode, a Hg / HgO electrode as the reference electrode, and a NiO x The electrode sheet was used as the working electrode. The working electrode was pulsed in 1M potassium hydroxide solution. A short pulse of -2V cathode potential was applied for 1s, and a short pulse of 2V anode potential was applied for 1s. The above short pulses of cathode potential and anode potential were applied 50 times. x Surface defects are introduced into the electrode sheet to obtain an activated nickel oxide working electrode.

[0072] S4, a mixed solution containing 1M potassium hydroxide and 100µM IrCl4·xH2O was prepared as an electrolyte, and electrochemical deposition was performed on the activated nickel oxide working electrode at a voltage of 6V for 10000s to obtain a nickel oxide-based iridium electrodeposition catalyst, which was recorded as NiO x -Ir.

[0073] The performance of the catalysts prepared in the above examples and comparative examples was tested, and the results are as follows.

[0074] Figure 1 This is a spherical aberration corrected high-angle annular dark field scanning transmission electron microscopy image of the nickel oxide-based iron-iridium dual electrodeposition catalyst prepared in Example 1 of the present invention. As can be seen from Figures (a) and (b), Fe and Ir are uniformly distributed in the form of nanoclusters and a small amount of single atoms on the NiO x A layer of iron oxide film grows on the substrate and outside the substrate. Figure 1 Figures (c) to (e) respectively show the Ir, O, and Ni elements in NiO. x The catalyst is evenly distributed on the substrate, and the multi-scale site distribution on the surface increases the active surface area of ​​the catalyst, allowing more reactants to contact the active sites, thereby improving the catalytic efficiency. The coexistence of single atoms and nanoclusters can produce a synergistic effect, further improving the catalytic performance. x The substrate provides a stable support for the metal sites, and the introduction of metal sites also changes the NiO x , thereby enhancing the catalytic performance.

[0075] Figure 2 Linear sweep voltammetry curves of the catalysts prepared in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3 for OER reactions. Figure 3 The catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention were tested at 10 mA·cm -2 The overpotential required for the OER reaction to occur in electrocatalytic water splitting. Figure 2 and Figure 3 As shown, NiO xAn overpotential of 320 mV is required to reach 10 mA cm -2 However, after the introduction of Ir single atoms, the overpotential is significantly reduced to 197mV and 254mV, respectively. x -IrFe 0.2 and NiO x -IrFe overpotentials are 198mV and 201mV, respectively, which are comparable to NiO x -Ir. This shows that the synergistic introduction of Fe and Ir greatly reduces the potential required for the OER reaction, and Example 2 still maintains high efficiency at low iron precursor concentrations, confirming the dual advantages of stability and catalytic efficiency of the catalyst system. NiO x -Fe overpotential reaches 254mV, which is higher than that of bimetallic co-deposition in Examples 1 and 2, highlighting the insufficient activity of Fe electrodeposition alone in the OER reaction; NiO x -Ir overpotential is 197mV, which is comparable to the performance of the embodiment, but from the perspective of cost-effectiveness, the pure Ir electrodeposition catalyst is obviously inferior to the Fe and Ir co-deposition system. From the overall trend of the curve, the starting potential of the catalyst of the embodiment is significantly reduced, which means that it can trigger the OER reaction at a lower potential. In the high potential range, the current density rises rapidly, showing a strong reaction kinetics; on the other hand, pure NiO x The slow growth of current density at high potential reflects the poor reaction kinetics of the catalyst.

[0076] Figure 4 The Tafel slope diagram of the OER reaction of the electrocatalytic water decomposition of the catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention. Figure 4 It can be seen that pure NiO x The Tafel slope of the catalyst is 78.96 mV·dec -1 , while single metal deposited NiO x -Ir、NiO x The Tafel slope of -Fe is 57.46 mV·dec -1 and 72.08mV·dec -1 , compared with pure NiO x It is shown that the introduction of Ir or Fe improves the reaction kinetics to a certain extent. x -IrFe 0.2 and NiO x -IrFe has a lower Tafel slope of 53.06 mV·dec. -1 and 51.37mV·dec -1 , significantly lower than single metal modification and pure NiO xThis indicates that the coordinated deposition of Ir and Fe can more effectively reduce the kinetic barrier of the reaction and accelerate the charge transfer process compared to the deposition of a single metal. x -IrFe exhibits the smallest Tafel slope, which means that it has the best reaction kinetics in the oxygen evolution reaction and can promote the reaction at a faster rate.

[0077] Figure 5 The electrochemical active surface area diagram obtained by cyclic voltammetry for the electrocatalytic water decomposition OER reaction of the catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention. Figure 5 It can be seen that in the bimetallic deposition catalyst, NiO x -IrFe 0.2 and NiO x -IrFe C a The values ​​are 41.00 mF·cm -2 and 28.16 mF·cm -2 , although lower than NiO x -Ir, but still much higher than pure NiO x With NiO x -Fe, confirming that co-deposition of Fe and Ir can effectively increase the number of active sites. A larger ECSA indicates that more active sites are exposed on the catalyst surface, such as Ni 3+ , oxygen vacancies, etc., provide ample catalytic active sites for the OER reaction. At the same time, a higher electrochemically active surface area corresponds to a larger double-layer capacitance, reflecting the excellent charge storage and transfer efficiency of the catalyst interface, which can accelerate the kinetics of *OH adsorption and OO bond formation, thereby improving the activity and stability of the catalytic reaction.

[0078] Figure 6 The catalysts prepared in Examples 1 to 2 and Comparative Examples 1 to 3 of the present invention were tested at 10 mA·cm -2 The stability test diagram of the OER reaction of electrocatalytic water splitting is evaluated by measuring the time required for the potential to increase by 100mV. Figure 6 It can be seen that pure NiO x The potential rises by 100mV in just 50h. x -IrFe 0.2 and NiO x -IrFe takes 232h and 261h to rise 100mV, especially NiO x -IrFe is more stable than pure NiO xThis improvement, exceeding fivefold, highlights the crucial role of the dual-site synergistic effect of iron and iridium in suppressing catalyst degradation. This result demonstrates that the iron-iridium dual-deposition catalyst can maintain efficient catalytic performance over extended periods of operation, making it suitable for sustained operation in practical applications. The excellent stability also demonstrates the catalyst's excellent resistance to corrosion and poisoning, maintaining stability in complex electrolyte environments.

[0079] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a nickel oxide-based iron-iridium dual electrodeposition catalyst, characterized in that: The following steps are involved: Using DL-α-alanine as ligand, Ni 2+ The Ni-alanine complex is formed by heating the Ni-alanine complex to 550°C to 620°C in an air atmosphere for pyrolysis, thereby decomposing the complex in the Ni-alanine complex to obtain a nickel oxide material. The nickel oxide material is prepared as a nickel oxide working electrode using an iron precursor, an iridium precursor and OH - The mixed solution of the source is an electrolyte, and an iron-iridium bimetallic is deposited on the nickel oxide working electrode by electrochemical deposition to obtain a nickel oxide-based iron-iridium dual electrodeposition catalyst; In the electrolyte, the molar ratio of the iridium precursor to the iron precursor is 1:0.2~2.

2. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 1, characterized in that: In the electrolyte, the molar ratio of the iridium precursor to the iron precursor is 1:

1.

3. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 1, characterized in that: The electrochemical deposition adopts the chronoamperometry method, the voltage is 5V~7V, and the electrochemical deposition time is 8000s~12000s.

4. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 1, characterized in that: Before electrochemical deposition, the nickel oxide working electrode is electrochemically activated, specifically by using a standard three-electrode － A short pulse of cathode potential of -2V to -1.5V for 0.5s to 1.5s and a short pulse of anode potential of 1.5V to 2V for 0.5s to 1.5s are sequentially applied to the nickel oxide working electrode in a solution.

5. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 4, characterized in that: One short pulse of cathode potential and one short pulse of anode potential was defined as one cycle, and the cycle was repeated 40 to 60 times.

6. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 1, characterized in that: The preparation method of the nickel oxide working electrode is as follows: the nickel oxide material, ethanol and Nafion are ultrasonically mixed and drop-coated on carbon paper to obtain a nickel oxide material loading of 0.8 mg / cm 2 ~2.3mg / cm 2 nickel oxide working electrode.

7. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 1, characterized in that: The Ni 2+ The molar ratio of the source to DL-α-alanine is 1:4~5.

8. The method for preparing the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 1, characterized in that: The pyrolysis time is 1.5h~3h.

9. A nickel oxide-based iron-iridium dual electrodeposition catalyst, characterized in that: The preparation method according to any one of claims 1 to 8 is used to prepare the compound.

10. Use of the nickel oxide-based iron-iridium dual electrodeposition catalyst according to claim 9 in catalytic electrolysis of water.

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