Method for preparing NiMo-MoO3-x porous nanorods and water electrolysis cathode catalyst containing the prepared NiMo-MoO3-x porous nanorods

Abstract

The present invention relates to NiMo-MoO prepared based on a metal-organic framework. 3-x This article relates to a method for producing a porous nanorod catalyst and a non-precious metal alloy catalyst produced thereby. The method for producing a non-precious metal alloy catalyst according to the present invention combines an alloy and an oxide to form nanorods that are porous and have a large surface area, enabling the production of an alloy catalyst with excellent HER performance comparable to that of commercial platinum catalysts.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0117227, filed on September 16, 2022, and all contents disclosed in the documents of said Korean Patent Application are incorporated herein by reference.

[0002] This disclosure describes NiMo-MoO 3-x Fabrication method of porous nanorods and NiMo-MoO nanorods fabricated from them 3-x Specifically, the present disclosure relates to a water electrolysis cathode containing porous nanorods. 3-x Fabrication method of porous nanorods and NiMo-MoO nanorods fabricated from them 3-x This invention relates to a water electrolysis cathode comprising porous nanorods. [Background technology]

[0003] Hydrogen is attracting attention as a potential next-generation fuel that provides sustainable and clean energy. Water electrolysis is a potential alternative to steam reforming, which produces hydrogen by reacting hydrocarbons with steam, for producing non-polluting hydrogen. Water electrolysis consists of a hydrogen evolution reaction (HER) at the cathode and an oxygen evolution reaction (OER) at the anode. Catalysts used for water electrolysis are precious metals such as Pt, Ru, and Ir. However, alkaline water electrolysis can use non-precious metal catalysts based on Ni, Fe, Co, and Mo because of fewer corrosion issues. While these catalysts are economically viable, they have a slow catalytic reaction rate. Therefore, the development of highly active catalysts that can improve the slow reaction rate in alkaline solutions and reduce the high overpotential is essential.

[0004] Precious metal catalysts, such as Pt, are known to be the most efficient catalysts for alkaline water electrolysis (HER). However, due to their scarcity and high cost, alternative non-precious metal-based catalysts must be developed. Recently, numerous studies have been published on non-precious metal catalysts for HER, including oxides, sulfides, phosphides, nitrides, and alloys. Among these, NiMo alloys have been evaluated for their high activity in alkaline HER. Although various NiMo alloys with diverse HER catalytic activities have been synthesized by adjusting morphology, surface area, porosity, and metal composition, their activity was lower than that of commercial Pt / C. Furthermore, the synthesized NiMo catalysts were deposited as thin films on substrates, which made them unsuitable for alkaline anion exchange membrane water electrolysis (AEMWE). Therefore, the development of an efficient powder-form NiMo catalyst with low overpotential and high stability is essential for the commercialization of AEMWE. Generally, permeable structures such as nanorods, nanowires, and nanoneedles can provide electrode materials with a more effective active area, improving material or charge transfer efficiency. Therefore, morphology engineering is an important part of optimal catalyst design. Porous materials derived from metal-organic frameworks (MOFs) have many more pores than other catalysts, and offer various advantages, such as a large surface area and adaptable morphology, which is important for catalytic activity. The present invention proposes MOF-derived NiMo-MoO catalysts for HER in alkaline water electrolysis. 3-x We aim to develop porous nanorod alloy catalysts. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] L. Yang, L. Zeng, HHLiu, Y. Deng, Z. Zhou, J. Yu, HHLiu, W. Zhou, Appl. Catal. B Environ. 2019, 249, 98. [Non-patent document 2] Y. Zhou, M. Luo, W. Zhang, Z. Zhang, X. Meng, X. Shen, H. Liu, M. Zhou, X. Zeng, ACS Appl.Mater.Interfaces 2019, 11, 21998. [Non-patent document 3] H.L., K.Liu, J.Fu, K.Chen, K.Yang, Y.Lin, B.Yang, Q.Wang, H.Pan, Z.Cai, H.Li, M.Cao, J.Hu, Y.Lu, T.Chan, E,Cortes, A.Fratalocchi, M.Liu, Nano energy 2021, 82, 105767. Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure provides porous nanorod-shaped NiMo-MoO nanoparticles that can exhibit excellent HER activity in alkaline electrolytes. 3-x The present invention provides a method for producing an alloy and a water electrolysis cathode catalyst containing the alloy. [Means for solving the problem]

[0007] Porous nanorod-shaped NiMo-MoO according to one embodiment of the present invention 3-x The method for producing the alloy includes the steps of: (1) preparing a nanorod-shaped NiMo-organic framework containing molybdenum oxide, nickel salt, and imidazole; (2) preparing porous nanorod-shaped NiMo oxide by heat-treating the nanorod-shaped NiMo-organic framework; and (3) preparing porous nanorod-shaped NiMo-MoO by reducing and heat-treating the porous nanorod-shaped NiMo oxide. 3-x producing an alloy (Step 3);

[0008] The x may be 0 or more and less than 3.

[0009] In another embodiment of the present invention, the water electrolysis cathode catalyst is a porous nanorod-shaped NiMo-MoO 3-x Contains alloys, The porous nanorod-shaped NiMo-MoO 3-x The alloys are 50 to 300 nm in diameter and 1 to 5 μm in length. [Effects of the Invention]

[0010] Porous nanorod-shaped NiMo-MoO prepared using a metal-organic framework by the manufacturing method of the present disclosure 3-x The alloy is porous and has improved conductivity and high surface area. The combination of the alloy and oxide can exhibit excellent HER activity in alkaline electrolytes when used as a cathode catalyst for water electrolysis. The manufacturing method of the present disclosure also allows for the production of porous nanorod-shaped NiMo-MoO 3-x The alloy can be mass-produced efficiently. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a method for producing NiMo-MoO3-x porous nanorods using a metal-organic framework according to one embodiment of the present disclosure, and shows the reaction mechanisms for each production step. [Figure 2] FIG. 2 is a comparative Fourier-transform infrared spectroscopy (FT-IR) graph of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is a Brunauer-Emmett-Teller (BET) comparison graph of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR according to one embodiment of the present disclosure. [Figure 4]FIG. 4 shows a scanning electron microscope (SEM) image (a) of MoO3 according to one embodiment of the present disclosure, high-resolution transmission electron microscope (HR-TEM) images of Ni-Mo-MOF-NR (b), NiMoO4-PNR (c), and NiMo-MoO3-PNR (d, e), as well as a selected area diffraction (SAED) pattern (f) and an energy dispersive analysis X-ray (EDAX) mapping image (g) of NiMo-MoO3-PNR. [Figure 5] FIG. 5 shows X-ray diffraction (XRD) pattern images of NiMoO4-PNR according to one embodiment of the present disclosure and NiMo-MoO3-PNR produced by varying the heat treatment temperature to 400, 500, 600, 700, and 800°C. [Figure 6] FIG. 6 is a comparative graph of X-ray photoelectron spectroscopy (XPS) measurements of Ni-2p and Mo-3d for NiMo-MoO3-PNR manufactured at heat treatment temperatures of 400, 500, 600, 700, and 800°C according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a graph comparing the HER performance of Ni-Mo-MOF-NRs, NiMoO4-PNRs, NiMo-MoO3-PNRs, and NiMo-MoO3 / C-NPNRs according to an embodiment of the present disclosure with Pt / C using linear sweep voltammetry (LSV). [Figure 8] FIG. 8 is a graph comparing the HER performance using linear sweep voltammetry (LSV) of NiMo-MoO3-PNRs manufactured at heat treatment temperatures of 400, 500, 600, 700, and 800°C according to an embodiment of the present disclosure. [Figure 9]FIG. 9 is a graph comparing the Tafel slope of NiMo-MoO3-PNR and Pt / C produced by varying the heat treatment temperature of one embodiment of the present disclosure between 400, 500, 600, 700, and 800°C. [Figure 10] FIG. 10 is a graph comparing the double layer capacitance of NiMo-MoO3-PNRs produced at heat treatment temperatures of 400, 500, and 600°C according to one embodiment of the present disclosure. [Figure 11] FIG. 11 is a graph comparing electrochemical impedance spectroscopy (EIS) of NiMo-MoO3-PNR and NiMo-MoO3 / C-NPNR with Pt / C according to one embodiment of the present disclosure. [Figure 12] FIG. 12 shows (a) a graph comparing the HER performance of the NiMo-MoO3-PNR according to one embodiment of the present disclosure before and after a 100,000 cycle test using linear sweep voltammetry (LSV), and (b) a graph showing a durability test using chronopotentiometry where 10, 50, and 10 mA cm-2 were measured for 1 hour, 100 hours, and 1 hour, respectively, for a total of 102 hours. [Figure 13] Figure 13 shows the SEM image of NiMo-MoO3-PNR after 100,000 cycles testing. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the present invention, terms such as "first" and "second" are used to describe various components, and the terms are used only to distinguish one component from another.

[0013] Furthermore, the terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprise," "include," "comprise," "have," and the like are intended to specify the presence of embodied features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, components, or combinations thereof.

[0014] Furthermore, in the present invention, when a layer or element is referred to as being formed "on" another layer or element, it means that the layer or element is formed directly on the other layer or element, or that other layers or elements may be additionally formed between the layers, on the object, or on the substrate.

[0015] Since the present invention can be modified in various ways and can have various forms, specific examples are exemplified and described in detail below, but it should be understood that this is not intended to limit the present invention to the particular disclosed form, and that the present invention includes any modifications, equivalents, or alternatives falling within the spirit and technical scope of the present invention.

[0016] In this disclosure, for convenience of description, the term "Ni-Mo-MOF-NR" is used to refer to a nanorod-shaped NiMo-organic framework, "NiMoO4-PNR" is used to refer to a porous nanorod-shaped NiMo oxide, and "NiMo-MoO 3-x -PNR" is a porous nanorod-shaped NiMo-MoO 3-x alloy, "NiMo-MoO 3-x / C-NPNR" is a NiMo-MoO nanoparticle containing a non-porous nanorod-shaped carbon layer. 3-x It means alloy.

[0017] Hereinafter, NiMo-MoO according to an embodiment of the present invention will be described.3-x The method for producing porous nanorods will now be described in detail.

[0018] Porous nanorod-shaped NiMo-MoO according to one embodiment of the present invention 3-x The method for producing the alloy is as follows: Step 1: preparing a nanorod-shaped NiMo-organic framework containing molybdenum oxide, nickel salt, and imidazole; Step 2: heat-treating the nanorod-shaped NiMo-organic framework to produce porous nanorod-shaped NiMo oxide; and The porous nanorod-shaped NiMo oxide was subjected to a reduction heat treatment to obtain porous nanorod-shaped NiMo-MoO 3-x producing the alloy (Step 3); Includes:

[0019] NiMo-MoO 3-x In the formula, x is equal to or greater than 0 and less than 3. Specifically, x may be equal to or greater than 0 and less than 1, or less than 0.5, or less than 0.3.

[0020] In step 1, the molybdenum oxide may be molybdenum dioxide (MoO2) or molybdenum trioxide (MoO3), preferably molybdenum trioxide (MoO3).

[0021] In step 1, the nickel salt may be a nickel halide. Specifically, it may be a nickel halide containing a halogen atom selected from the group consisting of halogens F, Cl, Br, and I. Preferably, the nickel salt may be nickel chloride (NiCl).

[0022] Specifically, step 1 may include dispersing molybdenum oxide, nickel salt, and imidazole in a solvent in solid form and stirring the mixture; refluxing the mixture; and separating, washing, and drying the precipitate after the refluxing step to obtain a nanorod-shaped NiMo-organic framework. The solvent may be deionized water.

[0023] In step 1, imidazole acts as a ligand to form a complex with molybdenum oxide and nickel salt, which can be expanded into a nanorod-shaped polymer. In particular, the reaction between molybdenum oxide and imidazole is possible only in the presence of nickel salt. This is because, according to the reaction mechanism, the two nitrogen atoms of the imidazole molecule transfer their lone electron pairs to molybdenum to form a covalent bond with molybdenum oxide. The two Mo-O - Ni 2+ Therefore, even if the molar ratio of the precursor inputs changes, the molar ratio of nickel to molybdenum in the final product is always maintained at 1:1. This reaction mechanism induces the one-dimensional growth of the NiMo-organic framework to produce nanorods.

[0024] In step 2, the nanorod-shaped NiMo-organic framework prepared in step 1 is heat-treated in an air atmosphere to thermally decompose the imidazole constituting the organic framework, forming a porous structure, and the molybdenum oxide and the nickel salt react to form NiMo oxide, thereby producing porous nanorod-shaped NiMo oxide. Specifically, the NiMo oxide may be NiMoO4.

[0025] The heat treatment temperature in step 2 may be 350 to 600° C. Specifically, the heat treatment temperature in step 2 may be 350° C. or higher, 400° C. or higher, or 450° C. or higher, and may be 600° C. or lower, 550° C. or lower, or 500° C. or lower.

[0026] If the heat treatment temperature in step 2 is too low, the imidazole cannot be sufficiently decomposed to form pores, which can result in the formation of NiMo oxide.At temperatures above 500°C, there is no mass change due to imidazole decomposition, so there is no reason to increase the temperature further.

[0027] In step 3, the porous nanorod-shaped NiMo oxide formed in step 2 is subjected to a reduction heat treatment to reduce the NiMo oxide, thereby forming porous nanorod-shaped NiMo-MoO 3-x In the step of producing the alloy, the heat treatment temperature may be 500°C or higher. Specifically, the heat treatment temperature in step 3 may be 500°C or higher, 550°C or higher, 600°C or higher, or 650°C or higher, and 800°C or lower, 750°C or lower, or 700°C or lower.

[0028] On the other hand, if the heat treatment temperature is too high, phase separation into Ni3Mo alloy and single Mo metal may occur, causing the porous nanorod shape to be destroyed into a non-porous state.

[0029] The heat treatment in step 3 may be performed in a mixed atmosphere of hydrogen and an inert gas. Specifically, the inert gas may be argon.

[0030] The porous nanorod-shaped NiMo-MoO prepared in step 3 3-x The atomic ratio of Mo to Ni in the alloy is always fixed at 1:1. Specifically, referring to the reaction mechanism in Figure 1, the reaction between MoO3 and imidazole produces Ni 2+ As a result, even if the molar ratio of the Ni and Mo precursors is changed, the final product is fixed at 1:1. In this case, oxygen may be contained in an amount of 10 to 20 wt%, specifically 15 to 17 wt%.

[0031] In addition, the water electrolysis cathode catalyst according to one embodiment of the present invention is a porous nanorod-shaped NiMo-MoO 3-x The porous nanorod-shaped NiMo-MoO alloy 3-xThe alloy may be 50 to 300 nm in diameter and 1 to 5 μm in length.

[0032] The porous nanorod-shaped NiMo-MoO 3-x The alloy may have a porous structure containing pores, said pores being between 10 and 25 nm.

[0033] The porous nanorod-shaped NiMo-MoO 3-x The alloy has a surface area of ​​50 to 100 m 2 / g.

[0034] Porous nanorod-shaped NiMo-MoO as a cathode catalyst for water electrolysis 3-x In the alloy, MoO3 active sites are effective in breaking H--OH bonds, and NiMo alloy active sites have the property of effectively switching the intermediate to H2 molecules. The large surface area through the porous structure improves the surface contact between the electrode material and the electrolyte, which increases the ion transport rate and reduces the charge transfer resistance, thereby increasing the number of active sites and increasing the catalytic activity. Therefore, the presence of MoO3 can help increase the catalytic activity.

[0035] Preferred examples are presented below to aid in understanding the present invention, but the following examples are merely for illustrative purposes and are not intended to limit the present invention.

[0036] Manufacturing example: Fabrication of porous nanorod-shaped NiMo-MoO3 alloy using MOF (Step 1) 1.0 g of molybdenum oxide (MnO), 1.63 g of nickel chloride (NiCl), and 2.67 g of imidazole were placed in a round-bottom flask and dispersed in 200 ml of deionized water. The mixture was then stirred at room temperature for 5 minutes. The mixture was refluxed in an oil-water bath at 120°C for 24 hours. The precipitate was recovered from the flask, washed with deionized water and ethanol, and dried at 60°C for 12 hours to obtain Ni-Mo-MOF-NR. (Step 2) Next, the Ni-Mo-MOF-NR was heated in an air atmosphere at a heating rate of 2°C / min and heat-treated at 450°C for 2 hours to produce light yellow NiMoO4-PNR. (Step 3) 200 mg of the NiMoO4-PNR was heat-treated in an atmosphere of 70% argon and 30% hydrogen at a heating rate of 5°C / min to 500°C for 2 hours, and then cooled to room temperature to obtain black NiMo-MoO3-PNR.

[0037] Experimental Example 1 Experiments were conducted to confirm the formation of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR in the above Preparation Examples. The mass ratios and atomic ratios of Ni and Mo in Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR were confirmed by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy) analysis and are shown in Table 1 below. The remainder of the total mass ratios and atomic ratios in Table 1 below was the oxygen content.

[0038] [Table 1]

[0039] As shown in Table 1, the atomic ratio of Ni to Mo was confirmed to be maintained at 1:1 regardless of the preparation step. Furthermore, as shown in Table 2, even when the Ni:Mo ratio was changed by changing the initial Ni salt and MoO salt concentrations, the Ni:Mo ratio in Ni-Mo-MOF-NR was always 1:1.

[0040] [Table 2]

[0041] In addition, the molecular structure and chemical composition of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR at each step of the preparation example were confirmed through FT-IR graphs (Figure 2). In particular, the FT-IR spectrum of Ni-Mo-MOF-NR showed a peak at 3430 cm -1 (H2O-OH), 3100-3300 cm -1 (NH / N=H), 2800-3000cm -1 (CH), 1630cm -1 The (C=C) stretching bands, which indicate imidazole characteristics, were observed. This confirmed that imidazole plays a role as a ligand in the formation of MOFs. The FT-IR spectrum of NiMoO4-PNR showed stretching bands at 807 and 879 cm -1 The Mo-O-Mo bond is at 965cm -1 The Mo=O bond is expressed as 633 cm -1 The FT-IR spectrum of NiMo-MOF-NR showed the characteristic Ni-O bond, confirming that NiMoO4 was generated from the Ni-Mo-MOF-NR precursor by the removal of the imidazole skeleton during sintering in air. -1 The relatively small peaks correspond to the Mo=O, Mo2-O, and Mo3-O bonds of MoO3, respectively.

[0042] Furthermore, the surface areas of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR were confirmed using Brunauer-Emmett-Teller (BET) (Figure 3). The surface areas of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR were 20.0, 74.5, and 61.6 m, respectively. 2 g -1 The average pore diameters of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR were 21.3, 10.0, and 7.4 nm, respectively, and the pore volumes were 0.05, 0.32, and 0.21 cm3g, respectively. -1This indicates that the Ni-Mo-MOF-NR does not have significant porosity. During sintering, mesopores were formed in the NiMoO4-PNR due to the decomposition of the imidazole framework, and this porous structure was maintained during the thermal reduction of NiMoO4-PNR to NiMo-MoO3-PNR. The large surface area and pore volume of the NiMo-MoO3-PNR catalyst allowed easier contact with the electrolyte, leading to faster ion transport and improved active site generation, which could increase catalytic activity.

[0043] The structures of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR at each step of the preparation example were confirmed.

[0044] Figure 4a shows an SEM image of MoO3 used in step 1. It was confirmed that MoO3 has a highly irregular structure, unlike the NiMo-MoO3-PNRs formed in the subsequent fabrication steps.

[0045] Figure 4b shows a TEM image of the Ni-Mo-MOF-NRs, which confirmed the formation of smooth nanorod structures.

[0046] After the heat treatment, it was confirmed that the imidazole was removed while maintaining the nanorod structure, and pores were formed in the remaining positions, resulting in the formation of a porous surface.

[0047] Figures 4d and 4e are TEM images of the final NiMo-MoO3-PNR. It was confirmed that the porous nanorod structure was maintained even after the reduction heat treatment. The diameter was confirmed to be about 50 to 300 nm, and the length was about 2.5 μm. Specifically, Figure 4e shows that the NiMo-MoO3-PNR has a high level of porosity (pore size (D 50 It was confirmed that the structure had a thickness of 10 to 25 nm.

[0048] The diffraction rings correspond to the NiMo alloy planes ((133), (043), (171), and (082)), confirming that the NiMo-MoO3-PNR is a crystalline catalyst. EDAX mapping of the NiMo-MoO3-PNR (Fig. 4g) showed that Ni, Mo, and O were uniformly dispersed.

[0049] Experimental Example 3 NiMo-MoO-PNR was prepared using the same method as in Preparation Example 1, except that NiMoO-PNR was heat-treated at various temperatures (400, 500, 600, 700, and 800°C). The effect of heat treatment temperature on the catalytic properties of NiMo-MoO-PNR was investigated. Figure 5 shows the XRD patterns of NiMo-MoO-PNR as a function of heat treatment temperature. The samples were designated Ni-Mo-x (x: heat treatment temperature). It was confirmed that a NiMo peak was formed at low heat treatment temperatures (400 and 500°C), while a Ni3Mo peak was formed at high heat treatment temperatures (600, 700, and 800°C). As the heat treatment temperature increased, NiMo-MoO-PNR phase-separated into Mo and Ni3Mo, resulting in the formation of mainly Mo and Ni3Mo peaks.

[0050] Figure 6 is a graph comparing the surface structure and electronic state of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR with different heat treatment temperatures, using XPS. The XPS spectra of Ni-Mo-MOF-NR and NiMoO4-PNR in Figure 6 have similar Ni 2p and Mo 3d peaks, which indicates that Ni and Mo have the same electronic state (Ni 2+ and Mo 6+ ) was shown to have

[0051] The XPS spectrum of NiMoO4-PNR heat-treated at 400°C indicated that NiMoO4-PNR was incompletely reduced to form a mixture of alloy and precursor as shown in the following reaction formula (I). In contrast, when NiMoO4-PNR was heat-treated at 600°C or higher, phase separation occurred as shown in the following reaction formula (III). NiMoO4-PNR heat-treated at 500°C showed that NiMo-MoO3-PNR was reduced to form NiMo alloy particles (NiMoO3) with traces of MoO3 as shown in the following reaction formula (II). 0 and Mo 0 It was confirmed that the catalyst is composed of MoO3. The presence of MoO3 helps increase catalytic activity, so a heat treatment temperature of 500°C is suitable. If the temperature is higher, phase separation may occur in the Mo metal, and if the temperature is too low, reduction may not be sufficient. This can be expressed by the following reaction equation.

[0052] [ka]

[0053] Experimental Example 4 Figure 7 shows the HER performance of the Ni-Mo-MOF-NR, NiMoO4-PNR, NiMo-MoO3-PNR, and NiMo-MoO3 / C-NPNR prepared as examples, as well as Pt / C, evaluated in 1.0 M KOH using linear sweep voltammetry (LSV). NiMo-MoO3 / C-NPNR is a catalyst in which nonporous NiMo nanorods are produced by directly carrying out steps 1 through 3 in Figure 1, without carbonizing the imidazole. The NiMo-MoO3-PNR catalyst has a higher HER catalytic activity (24.5 mV@10 mA cm) than not only Ni-Mo-MOF-NR and NiMoO4-PNR, but also nonporous NiMo-MoO3 / C-NPNR. -2 ) is quite high, and Pt / C (20.1 mV @ 10 mA cm -2 ) and demonstrated performance comparable to that of

[0054] Figure 8 shows the LSV of NiMo-MoO3-PNR catalysts prepared by heat-treating NiMoO4-PNR at different temperatures (400 to 800°C) as in Experimental Example 3. The NiMo-MoO3-PNR catalyst prepared at 500°C exhibited the highest HER catalytic activity. This is because the MoO3 active sites in the NiMo-MoO3-PNR formed at 500°C are effective at cleaving H--OH bonds, and the NiMo alloy active sites are effective at converting intermediates to H2 molecules, resulting in excellent HER activity. Furthermore, the porosity, crystalline structure, and surface area are thought to contribute to the excellent HER activity with high conductivity.

[0055] Figure 9 is a graph showing the Tafel slopes of NiMo-MoO3-PNR catalysts prepared by heat treating NiMoO4-PNR at other temperatures (400 to 800°C) as in Experimental Example 3, NiMo-MoO3 / C-NPNR, and Pt / C. The Tafel slope of NiMo-MoO3-PNR prepared at 500°C was 32.0 mV dec. -1 The lowest Tafel slope indicates an increase in HER kinetics. -1 ) lower than Pt / C (28.5mV dec -1 ) is comparable to the level of

[0056] The catalytic activity of the NiMo-MoO3-PNR prepared by the above Preparation Example method is compared with that of previously reported NiMo catalysts and is shown in Table 3 below.

[0057] [Table 3]

[0058] According to Table 3 above, the NiMo-MoO3-PNR of the preparation example has superior HER activity to previously reported NiMo catalysts due to the synergistic effect of the MoO3 active sites and the NiMo alloy active sites.

[0059] Cyclic voltammetry (CV) was used to obtain the electrochemical surface areas (ECSA) and double-layer capacitance (C dl ) was measured. Figure 10 shows the C of NiMo-MoO3-PNR catalysts prepared by heat treating NiMoO4-PNR at other temperatures (400 to 600°C) as in Experimental Example 3. dl The C of NiMo-MoO3-PNR prepared at 500°C is shown. dl is 259.2 mF cm -2 was the largest, with 400°C and 600°C showing 187.4 and 112.2 mF cm, respectively. -2 and appeared. The NiMo-MoO3-PNR of the manufacturing example has a lower charge-transfer resistance (R ct ) was the lowest, and the non-porous NiMo-MoO3 / C-NPNR had a higher R than the porous NiMo-MoO3-PNR. ct The low R of NiMo-MoO3-PNR was very large (Fig. 11). ct The value was understood to be due to the increased HER catalytic activity due to the porous structure and large surface area.

[0060] Experimental Example 5 The stability of the NiMo-MoO3-PNR prepared according to the Preparation Example (Figure 12a) is a graph comparing the results before and after a 100,000 cycle test, confirming the excellent stability of the catalyst. The overpotential of the NiMo-MoO3-PNR prepared according to the Preparation Example hardly increased during the cycle test, indicating that the cycle test had little effect on the decline in catalytic activity.

[0061] Figure 12b shows the NiMo-MoO3-PNR fabricated according to the Preparation Example, with different current densities (10, 50, 10 mA cm -2This figure shows a chronopotentiometry test graph measured at 1 hour, 100 hours, and 1 hour intervals for a total of 102 hours. Minor fluctuations in voltage were observed during the measurement, which is thought to be due to the repeated gathering and dispersal of H2 bubbles generated by the HER reaction on the catalyst surface. After 102 hours, the overpotential confirmed by the Vt curve remained almost unchanged. This indicates that the NiMo-MoO3-PNR catalyst has excellent electrochemical stability and mechanical hardness.

[0062] Experimental Example 6 Figure 13 shows an SEM image of the NiMo-MoO3-PNR fabricated according to the example, measured after 100,000 cycles. It was found that the nanorod structure was preserved even after the cycle test. According to the experimental example, a very low overpotential (24.5 mV) was achieved with the non-precious metal-based catalyst of the present invention, i.e., NiMo-MoO3-PNR, which has high cycle stability (100,000 cycles) and durability of more than 102 hours. This indicates that the NiMo-MoO3-PNR of the present invention exhibits excellent efficiency and can be easily used as an anode catalyst in industrial hydrogen production.

Claims

1. Step 1: preparing a nanorod-shaped NiMo-organic framework containing molybdenum oxide, nickel salt, and imidazole; Step 2: heat-treating the nanorod-shaped NiMo-organic framework to prepare porous nanorod-shaped NiMo oxide; and The porous nanorod-shaped NiMo oxide was subjected to a reduction heat treatment to obtain porous nanorod-shaped NiMo-MoO ３－ｘ Producing the alloy (Step 3); Including, The x is 0 or more and less than 3. ３－ｘ Methods for producing alloys.

2. The molybdenum oxide is molybdenum trioxide (MoO ３ ) The porous nanorod-shaped NiMo-MoO of claim 1 ３－ｘ Methods for producing alloys.

3. The nickel salt is a nickel halide. The porous nanorod-shaped NiMo-MoO of claim 1 ３－ｘ Methods for producing alloys.

4. The heat treatment temperature in step 2 is 350 to 600°C. The porous nanorod-shaped NiMo-MoO of claim 1 ３－ｘ Methods for producing alloys.

5. The porous nanorod-shaped NiMo-MoO ３－ｘ The Mo to Ni atomic ratio of the alloy is 1:1; The method for producing the nanorod-shaped NiMo alloy according to claim 1 .

6. The heat treatment temperature in step 3 is 500°C or higher. The porous nanorod-shaped NiMo-MoO of claim 1 ３－ｘ Methods for producing alloys.

7. The heat treatment in step 3 is carried out in a mixed atmosphere of hydrogen and an inert gas. The porous nanorod-shaped NiMo-MoO of claim 1 ３－ｘ Methods for producing alloys.

8. Porous nanorod-shaped NiMo-MoO ３－ｘ Contains alloys, The porous nanorod-shaped NiMo-MoO ３－ｘ The alloy has a diameter of 50 to 300 nm and a length of 1 to 5 μm. Water electrolysis cathode catalyst.

9. The porous nanorod-shaped NiMo-MoO ３－ｘ The alloy contains pores, The pores have a size D ５０ is 10 to 25 nm; The water electrolysis cathode catalyst according to claim 8.

10. The porous nanorod-shaped NiMo-MoO ３－ｘ The alloy has a surface area of ​​50 to 100 m ２ / g, The water electrolysis cathode catalyst according to claim 8.

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