Ni based on hydrogen evolution reaction in alkaline environment 0.85 Se / NiMoO x Preparation method of heterojunction catalyst

Abstract

This invention is based on the Ni hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x The method for preparing heterojunction catalysts includes: S1, producing NiMoO4 nanorods on a nickel foam substrate via a hydrothermal reaction; S2, introducing nickel-molybdenum metal oxides to form NiMoO-NH by loading Ni(OH)2 nanosheets onto the NiMoO4 nanorods; S3, synthesizing Ni via selenization reduction and ion exchange. 0.85 Se / NiMoO x Heterojunction catalyst. The Ni obtained in this invention... 0.85 Se / NiMoO x Heterojunction catalysts possess a multi-level structure of nanosheets coated with nanorods, abundant active sites, and excellent mass transfer capabilities, while crystalline Ni... 0.85 Se and amorphous NiMoO x The combination modulates the electronic structure of the catalyst surface and interface, optimizes the adsorption and desorption of reaction intermediates, and accelerates HER kinetics.

Description

Technical Field

[0001] This invention relates to the fields of water electrolysis and hydrogen evolution reaction catalysis, specifically to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Methods for preparing heterojunction catalysts. Background Technology

[0002] Electrolysis of water is a green and environmentally friendly technology with the potential to solve energy and ecological problems globally. However, its effectiveness is limited by the slow reaction kinetics of the oxygen evolution reaction (OER) at the anolyte and the hydrogen evolution reaction (HER) at the cathode. In recent years, transition metal-based electrocatalysts have become a research hotspot for hydrogen production through water electrolysis due to their low cost and abundant reserves. In particular, selenides among transition metal chalcogenides possess high conductivity, tunable d-electron structure, and good HER activity, making them a promising alternative to the precious metal Pt in hydrogen production through water electrolysis. Research results indicate that Ni… x Se y With appropriate d-electron configuration, Ni x Se y The Se atoms at the edges are HER active sites, such as in NiSe nanosheets and Ni 0.85 Se nanosheets, etc. Therefore, researchers have been working to develop multi-metallic nickel-based selenide electrocatalysts and selenide materials of different morphologies through various cation doping and crystal phase engineering strategies. For example, Ni... 0.33 Co 0.67 Se2 / CFP nanowires, Ni 0.89 Co 0.11 Se2MNSN / NF porous nanosheets and Co-like network structures 0.6 Ni 0.4 Se2-LN, etc. Although these catalysts significantly increase the number of edge active sites, their catalytic activity is still limited by the slow water dissociation step under alkaline conditions, and further improvements are needed. Furthermore, under long-term testing conditions, these nanosheets or nanoparticles are prone to aggregation, leading to deformation, decreased stability, and reduced electrocatalytic activity.

[0003] The dissociation adsorption energy of H2O on the catalyst and H * and OH -The adsorption energy is one of the three key factors affecting the alkaline HER process. Accordingly, to overcome the sluggish kinetics of alkaline HER, efficient HER electrocatalysts should be designed based on the following principles: low water dissociation energy barrier and appropriate hydrogen binding energy and hydroxyl binding energy (HBEs and OHBEs). However, due to structural relationships, these intrinsic functional requirements are difficult to simultaneously meet in single-component electrocatalysts. Conversely, when two different components come into contact to form a heterostructure, atomic configurations are rearranged and electronic structures are adjusted near the heterointerface. Liu et al. constructed an amorphous / crystalline CoBO... x / NiSe heterostructure for high-efficiency water electrolysis (HER: 14.5mV@10mA·cm -2 OER: 229.1mV@10mA·cm -2 Composite electrocatalysts composed of different functional components offer the potential for simultaneous fine-tuning of water dissociation kinetics, H* and OH adsorption and desorption capabilities, which is beneficial for alkaline HER processes. Nickel-based alloys hybridized with metal oxides have been reported to exhibit high efficiency in alkaline HER due to the high H2 evolution activity of nickel-based alloys and the good water dissociation capability of metal oxides. To improve the activity of selenide catalysts, Mo-doped NF@Mo-Ni... 0.85 SeNSs and NiFe(OH) x Coupled (Ni,Fe)Se₂NSs are stable and efficient catalysts. Additionally, flower-shaped NiSe₂-NiMoO₄ heterojunctions and CoFe-LDH@NiSe on NiSe nanosheets are also stable and efficient catalysts. Through the synergistic effect of constructing interfaces and heterostructures, electron transfer, active sites, and catalytic activity can be effectively modulated.

[0004] Therefore, Ni composites of nickel and molybdenum metal oxides 0.85 Se exhibits excellent HER activity, therefore, this application designed and synthesized Ni nanosheets with wrinkled coatings on nanorods. 0.85 Se / NiMoO x The catalyst is more suitable for alkaline hydrogen evolution. Summary of the Invention

[0005] This invention is based on the Ni hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Methods for preparing heterojunction catalysts include:

[0006] S1. NiMoO4 nanorods are produced on a nickel foam substrate via hydrothermal reaction;

[0007] S2. Introduce nickel-molybdenum metal oxides to form NiMoO-NH by loading Ni(OH)2 nanosheets on NiMoO4 nanorods;

[0008] S3. Ni is synthesized via selenization reduction and ion exchange. 0.85 Se / NiMoO x Heterojunction catalyst.

[0009] Preferably, the nickel foam substrate in S1 is pretreated; the pretreatment includes the removal of surface oxides and oil stains from the nickel foam substrate, specifically including: immersing the nickel foam in acetone, 3MHCl, water, and ethanol in sequence for ultrasonic cleaning for 12-15 minutes, and then placing the pretreated nickel foam in anhydrous ethanol for later use.

[0010] Preferably, the synthesis of NiMoO4 nanorods in S2 specifically includes the following steps:

[0011] S2.1.1 Take a clean 50mL beaker, add 36-40mL of H2O to the beaker, and then weigh 0.4-0.5g of Ni(NO3)2·6H2O and 0.4-0.5g of (NH4)6Mo7O using a balance. 24 • 4H₂O and 0.1-0.2g NH₄F;

[0012] S2.1.2 Add the ingredients to the beaker in sequence and stir until the solution is clear and transparent;

[0013] S2.1.3 Transfer the solution to a 50mL reaction vessel liner and place pretreated nickel foam inside. Then, place the sealed reaction vessel in an electric heating oven for the reaction.

[0014] S2.1.4 After the reaction is complete, the mixture is allowed to cool naturally to room temperature, washed multiple times with ethanol and water, and dried in an electric heating oven at 60-65℃ to obtain NiMoO4 nanorods.

[0015] Preferably, the nickel nitrate concentration of Ni(NO3)2·6H2O weighed by a balance in S2.1.1 is 0.04-0.05 mol / L; the (NH4)6Mo7O weighed by a balance 24 The concentration of ammonium molybdate in ·4H2O is 0.01-0.02 mol / L; the concentration of ammonium fluoride in NH4F, weighed by a balance, is 0.1-0.15 mol / L.

[0016] Preferably, the reaction is carried out in a sealed reactor in step S2.1.3 within a discharge-heated oven at 5-8°C for 1 minute. -1 The rate of heating is increased, and the hydrothermal reaction is carried out at 160-165℃ for 6-6.5 hours.

[0017] Preferably, the synthesis of NiMoO-NH in S2 specifically includes the following steps:

[0018] S2.2.1. Using NiMoO4 nanorods as a substrate, Ni(OH)2 nanosheets are introduced to form a wrinkled structure of NiMoO-NH nanocoated nanorods.

[0019] S2.2.2 Take a precursor NiMoO4 nanorod and immerse it in 36-38 mL of a solution containing 40-42 mM nickel nitrate, 160-165 mM urea and 240-245 mM ammonium fluoride;

[0020] S2.2.3 Transfer to the Teflon liner of a 50mL high-pressure reactor, place the sealed reactor in an electric heating oven, and perform a hydrothermal reaction at 160-165℃ for 6-6.5 hours, then allow it to cool naturally to room temperature.

[0021] S2.2.4. The NiMoO-NH obtained by washing several times with ethanol and water and drying overnight in an electric heating oven at 60-65℃.

[0022] Preferably, Ni in S3 0.85 Se / NiMoO x The synthesis includes the following steps:

[0023] S3.1 Take the hydrothermal product NiMoO-NH, weigh 0.15-0.18g of Se powder and pour it into a beaker containing 36-38mL of ultrapure water and stir evenly;

[0024] S3.2 Weigh 0.3-0.35g of NaBH4 powder and pour it into a beaker. Stir until the selenium powder is completely dissolved, then transfer it to the lining of a 50-55mL reaction vessel.

[0025] S3.3 After immersing NiMoO-NH in the solution, seal the reactor and place the sealed reactor in an electric heating oven. After hydrothermal reaction at 160-165℃ for 6-6.5 hours, allow it to cool naturally to room temperature.

[0026] S3.4 Washed several times with ethanol and water, and finally dried overnight in an electric heating oven at 60-65℃. After natural cooling, black Ni was obtained. 0.85 Se / NiMoO x catalyst.

[0027] Preferably, in step S3.1, 0.15-0.18g of Se powder is weighed and poured into a beaker containing 36-38mL of ultrapure water and stirred until homogeneous, wherein the Se powder is 2-2.2mmol.

[0028] Compared with the prior art, the technical solution of this application has the following technical effects:

[0029] The Ni of the present invention 0.85 Se / NiMoOx Heterojunction catalysts possess a multi-level structure of nanosheets encapsulated in nanorods, abundant active sites, and excellent mass transfer capabilities. Meanwhile, crystalline Ni... 0.85 Se and amorphous NiMoO x The combination modulates the electronic structure of the catalyst surface and interface, optimizes the adsorption and desorption of reaction intermediates, and accelerates HER kinetics.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0031] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0033] Figure 1 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Overall flow chart of heterojunction catalyst preparation method

[0034] Figure 2 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Flowchart of NiMoO4 nanorod synthesis method for preparing heterojunction catalyst;

[0035] Figure 3 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Synthesis flow chart of NiMoO-NH in heterojunction catalyst preparation method;

[0036] Figure 4 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO xNi 0.85 Se / NiMoO x Synthesis flowchart;

[0037] Figure 5 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x X-ray diffraction pattern of heterojunction catalyst preparation method;

[0038] Figure 6 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Scanning electron microscope image of the heterojunction catalyst preparation method;

[0039] Figure 7 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Ni 0.85 Se / NiMoO x Scanning electron microscope image;

[0040] Figure 8 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Ni 0.85 Se / NiMoO x High-resolution electron microscope image;

[0041] Figure 9 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Ni 0.85 Se / NiMoO x XPS spectra;

[0042] Figure 10 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x XPS spectra comparison of heterojunction catalyst preparation methods;

[0043] Figure 11 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Comparison of hydrogen evolution methods in heterojunction catalyst preparation;

[0044] Figure 12 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoOx Cyclic voltammetry curves for heterojunction catalyst preparation methods;

[0045] Figure 13 This invention relates to Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Stability test diagram of heterojunction catalyst preparation method. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0047] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0048] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0049] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0050] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0051] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0052] Example 1

[0053] This embodiment mainly describes Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Detailed preparation methods for heterojunction catalysts, such as Figure 1 As shown, it includes:

[0054] S1. NiMoO4 nanorods are produced on a nickel foam substrate via hydrothermal reaction;

[0055] S2. Introduce nickel-molybdenum metal oxides to form NiMoO-NH by loading Ni(OH)2 nanosheets on NiMoO4 nanorods;

[0056] S3. Ni is synthesized via selenization reduction and ion exchange. 0.85 Se / NiMoO x Heterojunction catalyst.

[0057] Furthermore, the nickel foam substrate in S1 is pretreated; the pretreatment includes the removal of surface oxides and oil stains from the nickel foam substrate, specifically including: immersing the nickel foam in acetone, 3MHCl, water, and ethanol in sequence for ultrasonic cleaning for 15 minutes, and then placing the pretreated nickel foam in anhydrous ethanol for later use.

[0058] Furthermore, such as Figure 2 As shown, the synthesis of NiMoO4 nanorods in S2 specifically includes the following steps:

[0059] S2.1.1 Take a clean 50mL beaker, add 36mL of H2O to the beaker, and then weigh 0.4187g of Ni(NO3)2·6H2O and 0.4449g of (NH4)6Mo7O using a balance. 24 • 4H₂O and 0.1333g NH₄F;

[0060] S2.1.2 Add the ingredients to the beaker in sequence and stir until the solution is clear and transparent;

[0061] S2.1.3. Transfer the solution to a 50 mL reactor liner and place a 1*5 cm layer of pretreated nickel foam inside. 2 In the process, the sealed reactor is placed in an electric heating oven for reaction;

[0062] S2.1.4 After the reaction is complete, the mixture is allowed to cool naturally to room temperature, washed multiple times with ethanol and water, and dried in an electric heating oven at 60°C to obtain NiMoO4 nanorods.

[0063] Furthermore, the nickel nitrate concentration of Ni(NO3)2·6H2O weighed using a balance in S2.1.1 is 0.04 mol / L; the (NH4)6Mo7O weighed using a balance... 24 The concentration of ammonium molybdate in ·4H2O is 0.01 mol / L; the concentration of ammonium fluoride in NH4F, which is weighed using a balance, is 0.1 mol / L.

[0064] Furthermore, the reaction is carried out in the sealed reactor in step S2.1.3 within a discharge hot air drying oven at 5°C for 5 minutes. -1 The rate of heating was increased and the hydrothermal reaction was carried out at 160°C for 6 hours.

[0065] Furthermore, such as Figure 3 As shown, the synthesis of NiMoO-NH in S2 specifically includes the following steps:

[0066] S2.2.1. Using NiMoO4 nanorods as a substrate, Ni(OH)2 nanosheets are introduced to form a wrinkled structure of NiMoO-NH nanocoated nanorods.

[0067] S2.2.2 Take a precursor NiMoO4 nanorod and immerse it in a 36 mL solution containing 40 mM nickel nitrate, 160 mM urea and 240 mM ammonium fluoride.

[0068] S2.2.3 Transfer to the Teflon liner of a 50mL high-pressure reactor, place the sealed reactor in an electric heating oven, and allow it to undergo hydrothermal reaction at 160℃ for 6 hours before naturally cooling to room temperature;

[0069] S2.2.4. The NiMoO-NH obtained by washing several times with ethanol and water and drying overnight in an electric heating oven at 60℃.

[0070] Furthermore, such as Figure 4 As shown, Ni in S3 0.85 Se / NiMoO x The synthesis includes the following steps:

[0071] S3.1 Take the hydrothermal product NiMoO-NH, weigh 0.1579g of Se powder and pour it into a beaker containing 36mL of ultrapure water and stir evenly.

[0072] S3.2 Weigh 0.3026g of NaBH4 powder and pour it into a beaker. Stir until the selenium powder is completely dissolved, then transfer it to the lining of a 50mL reaction vessel.

[0073] S3.3 After immersing NiMoO-NH in the solution, seal the reactor and place the sealed reactor in an electric heating oven. After hydrothermal reaction at 160°C for 6 hours, allow it to cool naturally to room temperature.

[0074] S3.4. Wash several times with ethanol and water, and finally dry overnight in a 60°C electric heating oven. After natural cooling, black Ni is obtained. 0.85 Se / NiMoO x catalyst.

[0075] Furthermore, in step S3.1, 0.1579g of Se powder is weighed and poured into a beaker containing 36mL of ultrapure water and stirred until homogeneous. The amount of Se powder is 2mmol.

[0076] This embodiment details Ni 0.85 Se / NiMoO x Specific methods for preparing heterojunction catalysts, Ni 0.85 Se / NiMoO x Heterojunction catalysts possess a multi-level structure of nanosheets coated with nanorods, abundant active sites, and excellent mass transfer capabilities, while crystalline Ni... 0.85 Se and amorphous NiMoO x The combination modulates the electronic structure of the catalyst surface and interface, optimizes the adsorption and desorption of reaction intermediates, and accelerates HER kinetics.

[0077] Example 2

[0078] This embodiment describes in detail the Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x Morphological characterization and verification of heterojunction catalysts, specifically including:

[0079] like Figure 5 As shown, the chemical composition and crystal structure of the catalyst were tested by XRD. The crystal structure of NiMoO4 is similar to that of NiMoO-NH catalyst. The diffraction peaks clearly show the characteristic diffraction peaks at 26.5°, 27.1°, and 33.7°, which correspond to the (220), (11-2), and (22-2) crystal planes of the NiMoO4 phase. The distribution has a good match with the standard PDF card of NiMoO4, proving that the hydrothermal reaction product contains nickel molybdate. The diffraction peaks of the nickel hydroxide phase generated by the second hydrothermal reaction are weaker. The characteristic diffraction peaks at 33.1°, 38.6°, and 52.1° correspond to the (110), (011), and (012) crystal planes of the Ni(OH)2 phase, respectively. The matching with the standard PDF card of Ni(OH)2 is good, proving that the second hydrothermal reaction synthesized nickel hydroxide nanosheets while retaining the NiMoO4 phase. After selenization, Ni 0.85 Se / NiMoO xThe catalyst's diffraction peaks clearly show characteristic diffraction peaks at 33.4°, 44.9°, 50.4°, and 60.2°, corresponding to Ni, respectively. 0.85 Se phase (101), (102), (110) and (103) crystal planes, with Ni 0.85 Se standard PDF card matching, and selenized Ni 0.85 Se / NiMoO x No species characteristic peaks related to nickel-molybdenum oxides were detected in the catalyst; Figure 5 The diffraction peaks at 44.5°, 51.8°, and 76.3° are shown to be from the Ni substrate.

[0080] NiMoO4, NiMoO-NH and Ni were analyzed by field emission scanning electron microscopy. 0.85 Se / NiMoO x The catalyst was tested, such as Figure 6 As shown, the NiMoO4 catalyst synthesized by hydrothermal reaction ( Figure 6 ab) The surface exhibits a nanorod array structure, which is compactly arranged and has a smooth and flat surface.

[0081] Following the second hydrothermal reaction, the nanorods on the surface of the NiMoO-NH catalyst were completely covered by nanosheet wrinkles, resulting in the growth of nanosheets with smooth and flat surfaces. Figure 6 The result (cd) indicates that nickel hydroxide nanosheets were successfully grown.

[0082] After selenization, Ni 0.85 Se / NiMoO x The catalyst surface becomes rougher, exhibiting a porous nanosheet structure, with nanoparticles forming on the surface of the nanosheets. Figure 6 ef).

[0083] After selenization, the nanorods coated with nanosheets exhibit a fluffy and porous structure, while fine nanowires and nanoparticles grow on the surface of the nanorods, such as... Figure 7 As shown ( Figure 7 ab), through Figure 7 It can be seen that this hierarchical structure is conducive to exposing more active sites and promoting electrolyte diffusion.

[0084] From Ni 0.85 Se / NiMoO x High-resolution transmission electron microscopy images of the catalyst, such as Figure 8 As shown, Figure 8 As can be seen, the catalyst consists of two parts: crystalline and amorphous, which form a heterogeneous interface, thus facilitating the adjustment of Ni. 0.85 Se / NiMoO xThe electronic structure of the catalyst promotes the adsorption and desorption of intermediates during the electrocatalytic HER process.

[0085] The lattice fringe spacing of the crystalline structure is 0.270 nm and 0.180 nm, respectively, corresponding to Ni 0.85 The (101) and (110) crystal planes of Se are consistent with the XRD results; combined with the analysis of the results, it is indicated that the catalyst is composed of crystalline Ni. 0.85 Se in amorphous NiMoO x Composed of two parts, as shown in the transmission electron microscope image ( Figure 8 b) shows that the catalyst is composed of nanoparticles, and its corresponding selected area electron diffraction pattern shows three diffraction rings ( Figure 8 c), respectively corresponding to Ni 0.85 The (101), (110), and (103) crystal planes of Se are consistent with the HRTEM results. Figure 8 d~i indicates that the four elements Ni, Mo, O and Se are uniformly distributed on the nanosheet.

[0086] This embodiment details the analysis of NiMoO4, NiMoO-NH, and Ni using field emission scanning electron microscopy. 0.85 Se / NiMoO x Electron microscopy images obtained from catalyst testing show that the Ni prepared in this application... 0.85 Se / NiMoO x The catalyst possesses high catalytic activity and stability.

[0087] Example 3

[0088] This embodiment is based on Example 1 and describes in detail the Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x The surface chemical states of heterojunction catalysts specifically include:

[0089] like Figure 9 As shown, the chemical state of the catalyst surface has a significant impact on the catalytic effect of the catalyst on HER. XPS was used to study Ni... 0.85 Se / NiMoO x Catalyst elemental composition and chemical state. Spectral peaks of Ni, Mo, O, and Se in the full-spectrum scan ( Figure 9 a) Consistent with EDS results;

[0090] right Figure 9 Peak fitting was performed on the fine XPS spectrum of Ni in b, and the peaks at 855.85 and 873.65 eV were attributed to Ni2p. 3 / 2 and Ni2p 1 / 2 The peaks at 861.12 and 879.14 eV are attributed to Ni satellite peaks. Figure 9The fine spectrum of Mo in c shows that the two peaks with binding energies of 232.14 and 235.21 eV belong to Mo. 6+ The characteristic peaks; while the two peaks at 228.79 and 232.14 eV are attributed to Mo. 4+ The peak is attributed to the partial formation of Mo during the selenization process. 6+ From a high valence state to a low valence state. Figure 9 The fine spectrum of Se in d shows two peaks with binding energies of 55.09 and 55.89 eV, which are attributed to Se3d. 5 / 2 and Se3d 3 / 2 (Se 2- The peak at 58.88 eV indicates that the surface selenium is in a high oxidation state (SeO). x It is formed due to surface oxidation caused by long-term exposure to air. Figure 9 The fine spectrum of O in e shows two peaks with binding energies of 530.87 and 532.57 eV, which belong to metal oxygen and adsorbed oxygen, respectively.

[0091] like Figure 10 As shown, Ni is further explained 0.85 Se composite NiMoO x The effects of NiMoO-NH and Ni were tested using XPS. 0.85 Se and Ni 0.85 Se / NiMoO x Chemical state of the surface elements of the catalyst.

[0092] Figure 10 Ni is shown in a. 0.85 Se and Ni 0.85 Se / NiMoO x Fine 3d spectra of the catalyst, compared with Ni 0.85 59.04 eV of Se catalyst (SeO) x ), Ni 0.85 Se / NiMoO x SeO catalyst x The peak (58.88 eV) undergoes a negative shift. Figure 10 b shows the fine spectrum of O1s, NiMoO-NH, Ni 0.85 Se and Ni 0.85 Se / NiMoO x The MO peak values ​​of the catalysts were 530.81, 530.8, and 530.75 eV, respectively, and the Ni... 0.85 Se / NiMoO x The catalyst MO peak shifted negatively. Figure 10 The fine spectrum of Mo3d in c shows that, compared to the NiMo-NH catalyst (Mo 6+Ni 0.85 Se / NiMoO x Mo catalyst 6+ Negative peak shift (Mo) 6+ (232.12 and 235.21 eV), and Mo appears 4+ Peak. Meanwhile, Figure 10 The fine spectrum of Ni2p in d shows that, compared to NiMo-NH catalyst (Ni2p... 3 / 2 855.56 and Ni2p 1 / 2 ,873.65eV), Ni 0.85 Se / NiMoO x The corresponding positive peak shift of the catalyst (Ni2p) 3 / 2 855.85 and Ni2p 1 / 2 (873.65 eV). XPS results show that Ni 0.85 Electron shift in Ni region of Se 0.85 Se / NiMoO x Mo Ni 0.85 The introduction of Se modulates Ni 0.85 Se / NiMoO x The electronic structure of crystalline Ni was demonstrated. 0.85 Se and amorphous NiMoO x Heterojunctions modulate the electronic structure of catalysts.

[0093] This embodiment details the Ni0.85Se / NiMoOx catalyst, whose optimized surface chemical state significantly improves catalytic performance and stability. XPS analysis revealed that the selenized Ni... 0.85 A heterostructure is formed between Se and NiMoOx. This structure not only modulates the electronic structure of the catalyst, but also optimizes the adsorption and desorption energies of the reaction intermediates, thereby accelerating the HER kinetics.

[0094] Example 4

[0095] This embodiment is based on Example 1 and describes in detail the Ni based on the hydrogen evolution reaction in an alkaline environment. 0.85 Se / NiMoO x The hydrogen evolution catalytic activity of heterojunction catalysts specifically includes:

[0096] like Figure 11 As shown, the HER polarization curve of the catalyst was measured at 30℃ in 1 MkOH solution. Figure 11 a) At low current densities, the 20% Pt / C catalyst exhibits the best performance in HER catalysis, while Ni... 0.85 Se / NiMoO xThe catalyst's catalytic performance is close to that of the Pt / C electrode (Ni 0.85 Se / NiMoO x 39mV@10mA·cm -2 153mV@100mA·cm -2 20% Pt / C: 34mV@10mA·cm -2 105mV@100mA·cm -2 Ni(OH)2, NiMoO4, NiMoO-NH and Ni 0.85 Se catalysts require overpotentials of 176, 250, 184, and 96 mV to reach 10 mA·cm⁻¹, respectively. -2 ( Figure 11 d). When the current increases to 500 mA·cm -2 At that time, Ni 0.85 Se / NiMoO x The catalytic activity of the catalyst exceeds that of the Pt / C catalyst (Ni 0.85 Se / NiMoO x 245mV@500mA·cm -2 ;20%Pt / C: 328mV@500mA·cm -2 Using Zview impedance analysis software, the following parameters were fitted: Ni(OH)₂, NiMoO₄, NiMoO-NH, and Ni 0.85 Se and Ni 0.85 Se / NiMoO x EIS impedance spectrum of the catalyst at an overpotential of -100 mV ( Figure 11 b). The order of the semicircle radii is NiMoO4. <Ni(OH)2<NiMoO-NH<Ni 0.85 Se <Ni 0.85 Se / NiMoO x This indicates that Ni 0.85 Se / NiMoO x The catalyst possesses the lowest charge transfer resistance, indicating that it exhibits the fastest HER kinetics, superior to Ni alone. 0.85 Se catalyst. Attributable to Ni 0.85 Se / NiMoO x The heterostructure modulates the electronic structure of the catalyst, accelerating the HER reaction kinetics.

[0097] Meanwhile, the smaller the Tafel slope, the faster the dynamic process, and the smaller the increase in potential when the same current density is reached. Figure 11 c shows Ni(OH)2, NiMoO4, NiMoO-NH, Ni 0.85 Se and Ni 0.85 Se / NiMoOx The Tafel slopes of the catalysts were 138, 150, 130, 98, and 85 mV·dec. -1 Among them, Ni 0.85 Se / NiMoO x The catalyst exhibits relatively fast HER kinetics, second only to 20% Pt / C (35 mV·dec). -1 ).

[0098] like Figure 12 As shown, for Ni 0.85 Se / NiMoO x The excellent HER catalyst activity is due to Ni without the addition of a Mo source. 0.85 Se catalyst and NiMoO without Se source x Catalyst and Ni 0.85 Se / NiMoO x CV testing of composite catalysts ( Figure 12 (a~c).

[0099] Ni 0.85 Se, NiMoO x and Ni 0.85 Se / NiMoO x C of catalyst dl The values ​​were 63.1, 13.9, and 264 mF·cm, respectively. -2 ( Figure 12 d); Ni 0.85 Se / NiMoO x Catalysts have the highest C dl The value indicates that the hierarchical structure of nanorods coated with nanosheets of distributed nanoparticles can effectively increase the active sites on the catalyst surface. NiMoO x Nanorod catalysts exhibit poor electrical conductivity, which is significantly improved after selenization. Meanwhile, Ni... 0.85 Se / NiMoO x The heterostructure of the catalyst optimizes the adsorption and desorption energies of the reaction intermediates, thus promoting the HER process.

[0100] like Figure 13 As shown, for Ni 0.85 Se / NiMoO x The catalyst exhibited good HER catalytic performance in 1 M KOH solution at 30 °C, and the stability of its HER catalytic activity over a long period was further investigated. Figure 13 Ni was tested using the galvanostatic method. 0.85 Se / NiMoO x The HER stability of the catalyst at a current density of 100 mA·cm -2 At that time, Ni 0.85Se / NiMoO x The catalyst maintained stable catalytic activity for up to 150 hours, indicating good catalyst stability. In summary, the Ni prepared in this study... 0.85 Se / NiMoO x The HER catalyst exhibits good catalytic performance and high stability.

[0101] This embodiment describes Ni in detail. 0.85 Se / NiMoO x The hydrogen evolution catalytic activity of the catalyst can be determined through the above tests. 0.85 Se / NiMoO x The catalyst modulates the electronic structure of the catalyst surface and interface, optimizes the adsorption and desorption of reaction intermediates, and accelerates HER kinetics.

[0102] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments within the spirit and principles of the present invention, without departing from the principles and spirit of the present invention, through conventional substitutions or to achieve the same function, fall within the scope of protection of the present invention.

Claims

1. Ni based on hydrogen evolution reaction in an alkaline environment 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, include: S1. NiMoO4 nanorods are produced on a nickel foam substrate via hydrothermal reaction; S2. Introduce nickel-molybdenum metal oxides to form NiMoO-NH by loading Ni(OH)2 nanosheets on NiMoO4 nanorods; S3. Ni is synthesized via selenization reduction and ion exchange. 0.85 Se / NiMoO x Heterojunction catalyst.

2. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 1 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, The nickel foam substrate in S1 is pretreated; the pretreatment includes the removal of surface oxides and oil stains from the nickel foam substrate, specifically including: immersing the nickel foam in acetone, 3M HCl, water, and ethanol in sequence for ultrasonic cleaning for 12-15 minutes, and then placing the pretreated nickel foam in anhydrous ethanol for later use.

3. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 1 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, The synthesis of NiMoO4 nanorods in S2 specifically includes the following steps: S2.1.1 Take a clean 50mL beaker, add 36-40mL of H2O to the beaker, and then weigh 0.4-0.5g of Ni(NO3)2·6H2O and 0.4-0.5g of (NH4)6Mo7O using a balance. 24 • 4H₂O and 0.1-0.2g NH₄F; S2.1.2 Add the ingredients to the beaker in sequence and stir until the solution is clear and transparent; S2.1.3 Transfer the solution to a 50mL reaction vessel liner and place pretreated nickel foam inside. Then, place the sealed reaction vessel into a discharge-heated forced-air oven for the reaction. S2.1.4 After the reaction is complete, the mixture is allowed to cool naturally to room temperature, washed multiple times with ethanol and water, and dried in an electric heating oven at 60-65℃ to obtain NiMoO4 nanorods.

4. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 3 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, The nickel nitrate concentration of Ni(NO3)2·6H2O weighed using a balance in S2.1.1 is 0.04-0.05 mol / L; the (NH4)6Mo7O weighed using a balance... 24 The concentration of ammonium molybdate in ·4H2O is 0.01-0.02 mol / L; the concentration of ammonium fluoride in NH4F weighed by the balance is 0.1-0.15 mol / L.

5. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 3 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, The reaction is carried out in the sealed reactor in S2.1.3 in a discharge hot air drying oven at 5-8℃ for 1 minute. -1 The rate of heating is increased, and the hydrothermal reaction is carried out at 160-165℃ for 6-6.5 hours.

6. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 1 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, The synthesis of NiMoO-NH in S2 specifically includes the following steps: S2.2.

1. Using NiMoO4 nanorods as a substrate, Ni(OH)2 nanosheets are introduced to form a wrinkled structure of NiMoO-NH nanocoated nanorods. S2.2.2 Take a precursor NiMoO4 nanorod and immerse it in 36-38 mL of a solution containing 40-42 mM nickel nitrate, 160-165 mM urea and 240-245 mM ammonium fluoride; S2.2.3 Transfer to the Teflon liner of a 50mL high-pressure reactor, place the sealed reactor in an electric heating oven, and perform a hydrothermal reaction at 160-165℃ for 6-6.5 hours, then allow it to cool naturally to room temperature. S2.2.

4. The NiMoO-NH obtained by washing several times with ethanol and water and drying overnight in an electric heating oven at 60-65℃.

7. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 1 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, Ni in S3 0.85 Se / NiMoO x The synthesis includes the following steps: S3.1 Take the hydrothermal product NiMoO-NH, weigh 0.15-0.18g of Se powder and pour it into a beaker containing 36-38mL of ultrapure water and stir evenly; S3.2 Weigh 0.3-0.35g of NaBH4 powder and pour it into a beaker. Stir until the selenium powder is completely dissolved, then transfer it to the lining of a 50-55mL reaction vessel. S3.3 After immersing NiMoO-NH in the solution, seal the reactor and place the sealed reactor in an electric heating oven. After hydrothermal reaction at 160-165℃ for 6-6.5 hours, allow it to cool naturally to room temperature. S3.4 Washed several times with ethanol and water, and finally dried overnight in an electric heating oven at 60-65℃. After natural cooling, black Ni was obtained. 0.85 Se / NiMoO x catalyst.

8. The Ni based on the hydrogen evolution reaction in an alkaline environment as described in claim 7 0.85 Se / NiMoO x The method for preparing heterojunction catalysts is characterized by, In step S3.1, 0.15-0.18g of Se powder is weighed and poured into a beaker containing 36-38mL of ultrapure water and stirred until homogeneous. The amount of Se powder is 2-2.2mmol.

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