A self-supporting IrRu-NiSe three-dimensional nanosheet array electrode and a preparation method and application thereof

Abstract

The application relates to a self-supporting IrRu-NiSe three-dimensional nanosheet array electrode and a preparation method and application thereof, and belongs to the technical field of hydrogen production by water electrolysis. A foam nickel is used as a nickel source and a substrate, an IrRu-NiSe three-dimensional array structure formed by super-thin nanosheets is constructed on the surface of the foam nickel through a two-step method of in-situ selenization and hydrothermal doping. The traditional high-temperature doping or physical mixing process is abandoned, and secondary hydrothermal reaction is adopted to realize accurate embedding of Ir / Ru atoms in the NiSe crystal lattice, to induce in-situ reconstruction of the material, to completely retain the nanosheet array morphology, and to significantly increase the specific surface area through the lattice doping effect. The design breaks through the bottleneck of the existing NiSe-based electrode, such as the lack of active sites and the blocking of electron transmission. The three-dimensional array structure constructs an efficient mass transfer channel, the Ir / Ru bimetallic synergistic doping optimizes the electronic structure and reduces the reaction energy barrier, and the two form a double synergistic advantage of structure and electrons. When the electrode is used as a hydrogen evolution / oxygen evolution dual-function electrode in an alkaline electrolyte, the electrode exhibits excellent catalytic activity and stability, and is especially suitable for industrialized water electrolysis hydrogen production scenes.

Description

Technical Field

[0001] A self-supporting IrRu-NiSe three-dimensional nanosheet array electrode, its preparation method and application, belongs to the field of water electrolysis hydrogen production technology. Background Technology

[0002] Among numerous non-noble metal catalysts, nickel selenide (NiSe) exhibits potential bifunctional catalytic activity in both HER and OER due to its excellent metallic conductivity and tunable electronic structure. Various NiSe-based nanostructures, such as nanosheets, nanowires, and nanospheres, have been widely developed to enhance their catalytic performance. However, these materials are typically in powder form and require coating onto a substrate using polymer binders. This process can easily mask active sites, increase interfacial resistance, and affect the structural stability of the electrode. Self-supporting electrocatalysts, with their high specific surface area, abundant electrolyte permeation and gas diffusion channels, excellent structural stability, and simplified electrode fabrication process, offer a highly attractive solution for improving HER and OER performance. Therefore, directly integrating NiSe nanostructures (such as nanosheets) onto a self-supporting conductive substrate is a key strategy to simultaneously achieve high catalytic activity and excellent mechanical stability.

[0003] In alkaline water splitting, Ru and Ir exhibit natural electronic complementarity. The ΔG of Ru... H The ruthenium (Ir) value is close to the thermodynamic ideal value, making it a highly efficient active center for HER (Heterogeneous Ester-Oxygenation). Ir, on the other hand, exhibits excellent structural stability under oxidation potential conditions, providing reliable support for OER (Organic Emission Reduction). By co-doping Ir and Ru into the NiSe lattice, bimetallic synergistic regulation can be achieved. The introduction of iridium optimizes the interaction of the ruthenium-oxygen bond, synergistically regulating the electronic structure, thus bringing the intermediate adsorption / desorption closer to thermodynamic equilibrium and effectively reducing the energy barrier. At the structural level, the difference in atomic radii between Ru and Ir induces non-uniform strain, thereby optimizing intermediate adsorption. This multi-center synergistic effect not only increases the active site density but also optimizes the coordination environment, simultaneously improving HER and OER performance under alkaline conditions. This invention does not simply combine "nickel foam support + nickel selenide + iridium-ruthenium," but rather employs a three-step synergistic design of "pretreatment - directional growth - doping control" to form a three-level synergistic system of "support - transition metal selenide - noble metal doping": the hydroxylation pretreatment of nickel foam provides anchor points for the directional growth of nickel selenide, the nickel selenide nanosheet array provides lattice sites for atomic-level doping of iridium-ruthenium, and the doping of iridium-ruthenium in nickel selenide achieves electronic structure control and uniform distribution of active sites. This synergistic design of "structure-doping-performance" overcomes the limitations of "independent action of each component" in existing technologies, and is something that those skilled in the art would find difficult to conceive of based on existing technologies. Summary of the Invention

[0004] Based on this, the purpose of this invention is to provide a self-supporting IrRu-NiSe three-dimensional nanosheet array electrode, its preparation method and application, aiming to solve the problem that existing nickel selenide-based materials cannot meet the catalytic activity and stability requirements under practical application conditions in the electrocatalytic hydrogen evolution and oxygen evolution processes.

[0005] The objective of this invention is achieved through the following technical solutions.

[0006] A self-supporting IrRu-NiSe three-dimensional nanosheet array electrode, the method comprising the following steps: Step 1. Place the nickel foam in the polytetrafluoroethylene liner of a hydrothermal reactor; add an aqueous solution containing selenium source and sodium borohydride to the liner to seal the reactor, heat to 120~180 ℃, and maintain the temperature for 6~24 h; after the reaction is completed, allow it to cool naturally to room temperature, remove the product, wash it 3~5 times alternately with deionized water and ethanol, and vacuum dry it (60~80 ℃, 4~6 h) to obtain the NiSe / nickel foam composite material grown in situ on the surface of nickel foam; Step 2. Immerse the NiSe / nickel foam composite material in a pre-prepared iridium-ruthenium mixed precursor solution, transfer the mixture to the polytetrafluoroethylene liner of a hydrothermal reactor, and seal the reactor; heat to 210 °C, maintain the temperature for 2 h, and allow to cool naturally to room temperature after the reaction is complete, then remove the product to obtain IrRu-NiSe nanosheet material.

[0007] Preferably, the specifications of the nickel foam in step 1 are 200mm*300mm*1.5mm.

[0008] Preferably, the molar ratio of selenium to nickel in the nickel foam in step 1 is 1:1 to 2:1.

[0009] Preferably, the mass ratio of selenium to sodium borohydride in step 1 is 1:1 to 1:2.

[0010] Preferably, in step 2, the iridium source is iridium chloride hexahydrate, the ruthenium source is ruthenium chloride trihydrate, the molar ratio of Ir to Ru is 1:1 to 3:1, and the total metal ion concentration is 0.01 to 0.1 mol / L. The self-supporting IrRu-NiSe three-dimensional nanosheet array electrode prepared by the method of this invention is used as a catalyst in water electrolysis for hydrogen production. Beneficial effects

[0011] The IrRu-NiSe three-dimensional nanosheet array electrode prepared by this invention exhibits a multi-level composite structure of "self-supporting substrate - in-situ grown active layer - doped modification sites": A highly conductive and highly porosimetric nickel foam serves as the self-supporting substrate, on which an in-situ selenization reaction grows a NiSe active layer in the form of a nanosheet array, forming continuous porous channels between the NiSe arrays. Through hydrothermal assisted ion exchange and subsequent heat treatment, Ir / Ru is uniformly dispersed in NiSe in the form of lattice doping, and a strong electronic interaction interface is formed between Ir / Ru and NiSe. This structure ensures both a high specific surface area and abundant exposure of active sites for the catalyst, while also constructing efficient electron transport and reactant / product diffusion channels through the porous structure and high conductivity of the nickel foam substrate, thus avoiding the problem of delamination between the active components and the substrate. Attached Figure Description

[0012] Figure 1 This is a schematic flowchart of the preparation method in Example 1 of the present invention; Figure 2 SEM image of the self-supporting NiSe three-dimensional nanosheet array electrode material prepared in Example 1; Figure 3 SEM image of the self-supporting IrRu-NiSe three-dimensional nanosheet array electrode material prepared in Example 1; Figure 4 TEM image of the self-supporting IrRu-NiSe three-dimensional nanosheet array electrode material prepared in Example 1; Figure 5 The image shows the XRD pattern of the self-supporting IrRu-NiSe three-dimensional nanosheet array electrode material prepared in Example 1.

[0013] Figure 6 The LSV polarization curve of the self-supported IrRu-NiSe three-dimensional nanosheet array electrode material prepared in Example 1 under alkaline hydrogen evolution conditions.

[0014] Figure 7 The LSV polarization curve of the self-supported IrRu-NiSe three-dimensional nanosheet array electrode material prepared in Example 1 under alkaline oxygen evolution conditions. Specific implementation methods

[0015] The following examples further illustrate the self-supporting IrRu-NiSe three-dimensional nanosheet array electrode, its preparation method, and its applications provided by the present invention, but these should not be construed as limiting the scope of protection of the present invention.

[0016] The devices used in the following embodiments include: Scanning electron microscope (SEM): JEOL JSM-7001F; Transmission electron microscope (TEM): JEM-2100PLUS; X-ray diffractometer (XRD): Rigaku ULTIMALV, Japan; Electrochemical workstation: Shanghai Chenhua CHI 760E, China. Example

[0017] (1) Cut the nickel foam into thin slices of 1.5 cm × 0.5 cm and sonicate them in 1 M hydrochloric acid, acetone, ethanol and ultrapure water for 30 min to remove oil and oxides from the substrate surface. Place the clean nickel foam in the polytetrafluoroethylene liner of the hydrothermal reactor; add an aqueous solution containing 0.0157 g selenium powder and 0.0151 g sodium borohydride to the liner to seal the reactor, heat to 180 ℃ and keep the temperature for 12 h; after the reaction is completed, cool naturally to room temperature, take out the product, wash it three times alternately with deionized water and ethanol, and vacuum dry (60, 6 h) to obtain NiSe / nickel foam composite material grown in situ on the surface of nickel foam.

[0018] (2) The NiSe / nickel foam composite material was immersed in a pre-prepared iridium-ruthenium mixed precursor solution, and the mixed system was transferred to the polytetrafluoroethylene liner of the hydrothermal reactor and the reactor was sealed. The temperature was raised to 210 °C and kept at the temperature for 2 h. After the reaction was completed, the product was naturally cooled to room temperature and the product was taken out to obtain the IrRu-NiSe three-dimensional nanosheet array electrode.

[0019] In step (2) of Example 1, the self-supporting NiSe nanosheet array electrode material is a vertically arranged nanoarray uniformly fixed on nickel foam, effectively increasing the contact surface area between the electrode material and the electrolyte. After iridium-ruthenium doping treatment, the morphology of the IrRu-NiSe nanoarray remains unchanged. Figure 2 and Figure 3 As shown.

[0020] according to Figure 4 As can be seen, the structure of IrRu-NiSe nanosheets was confirmed in step (2) of Example 1.

[0021] according to Figure 5 As can be seen, in step (2) of Example 1, the self-supporting NiSe three-dimensional nanosheet array electrode material is mainly composed of NiSe, and no impurity peaks attributable to metals Ir, Ru, or their oxides (such as IrO2, RuO2) were detected. This indicates that Ir and Ru elements do not exist in the form of independent crystalline phases, but have been successfully incorporated into the NiSe lattice.

[0022] according to Figure 6As can be seen, in Example 1, the self-supporting NiSe three-dimensional nanosheet array electrode material exhibits a low overpotential in alkaline hydrogen evolution, at 100 mA cm⁻¹. -2 The value is 38 mV.

[0023] according to Figure 7 As can be seen, in Example 1, the self-supporting NiSe three-dimensional nanosheet array electrode material exhibits a low overpotential in alkaline oxygen evolution, at 10 mA cm⁻¹. -2 The value is 110 mV.

[0024] In summary, this invention provides a self-supporting NiSe three-dimensional nanosheet array electrode material, its preparation method, and its applications. Using nickel foam as the nickel source and substrate, a NiSe nanosheet array composite material is synthesized via an in-situ selenization hydrothermal reaction. Then, uniform loading and anchoring of the Ir / Ru precursor are achieved through hydrothermal assisted ion exchange at 210 °C for 2 hours. The derived IrRu-NiSe hierarchical structure fully utilizes the high specific surface area and abundant active sites of the NiSe array. Ir / Ru doping optimizes the electronic structure, lowers the reaction energy barrier, and simultaneously strengthens the chemical bonding between the active components and the substrate. The hydrothermal assisted ion exchange process ensures efficient dispersion of Ir / Ru species while avoiding the damage to the material structure caused by additional high-temperature treatment, simultaneously improving the mass transfer efficiency and structural stability of the catalytic reaction. This self-supporting IrRu-NiSe catalyst can be widely applied in energy conversion technologies such as water electrolysis for hydrogen production. Furthermore, this catalyst exhibits low hydrogen / oxygen evolution overpotentials and excellent cycling stability over a wide pH range and industrial current density, effectively reducing the amount of precious metals used. It combines high performance and economy, and has broad application prospects.

[0025] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A self-supporting IrRu-NiSe three-dimensional nanosheet array electrode, the method comprising the following steps: Step 1. Place the nickel foam in the polytetrafluoroethylene liner of a hydrothermal reactor; add an aqueous solution containing selenium powder and sodium borohydride to the liner to seal the reactor, heat to 120~180 ℃, and maintain the temperature for 6~24 h; after the reaction is completed, allow it to cool naturally to room temperature, remove the product, wash it 3~5 times alternately with deionized water and ethanol, and vacuum dry it (60~80 ℃, 4~6 h) to obtain the NiSe / nickel foam composite material grown in situ on the surface of nickel foam; Step 2. Immerse the NiSe / nickel foam composite material in a pre-prepared iridium-ruthenium mixed precursor solution, transfer the mixture to the polytetrafluoroethylene liner of the hydrothermal reactor, and seal the reactor. The temperature was raised to 210 °C and the reaction was maintained for 2 h. After the reaction was completed, the product was naturally cooled to room temperature and the product was removed to obtain the IrRu-NiSe three-dimensional nanosheet array electrode.

2. The preparation method according to claim 1, characterized in that: The specifications of the nickel foam in step 1 are 200mm*300mm*1.5mm.

3. The preparation method according to claim 1, characterized in that: In step 1, the molar ratio of selenium powder to nickel in nickel foam is 1:1 to 2:

1.

4. The preparation method according to claim 1, characterized in that: In step 1, the mass ratio of selenium to sodium borohydride is 1:1 to 1:

2.

5. The preparation method according to claim 1, characterized in that: In step 2, the iridium source is iridium chloride hexahydrate, the ruthenium source is ruthenium chloride trihydrate, the molar ratio of Ir to Ru is 1:1 to 3:1, and the total metal ion concentration is 0.01 to 0.1 mol / L.

6. The application of the IrRu-NiSe three-dimensional nanosheet array electrode obtained by the preparation method according to any one of claims 1 to 5 as a catalyst in water electrolysis for hydrogen production.

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