Method for producing NiMo-MoO3-x porous nanorods and water electrolytic cathode catalyst containing the produced 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 of related applications] This application claims priority rights based on Korean Patent Application No. 10-2022-0117227 dated September 16, 2022, and all content disclosed in said Korean Patent Application is incorporated herein by reference.

[0002] This disclosure is for NiMo-MoO 3-x Method for manufacturing porous nanorods and NiMo-MoO2 produced therefrom 3-x This disclosure relates to a water electrolytic cathode containing porous nanorods. Specifically, this disclosure relates to a NiMo-MoO2 cathode using a metal-organic structure. 3-x Method for manufacturing porous nanorods and NiMo-MoO2 produced therefrom 3-x This relates to a water electrolysis cathode containing 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 water vapor, and can produce pollution-free 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 typically precious metals such as Pt, Ru, and Ir. However, in alkaline water electrolysis, corrosion is less of a problem, allowing the use of non-precious metal catalysts based on Ni, Fe, Co, and Mo, which is economically viable but results in slow catalyst reaction rates. Therefore, the development of highly active catalysts that can improve the slow reaction rates in alkaline solutions and reduce high overpotentials is essential.

[0004] While precious metal catalysts like platinum (Pt) are known to be the most efficient catalysts for alkaline water electrolysis (HER), their scarcity and high cost necessitate the development of non-precious metal-based catalysts that can replace them. Recently, numerous studies have been published on non-precious metal HER catalysts, including oxides, sulfides, phosphides, nitrides, and alloys. Among these, NiMo alloys have been evaluated as exhibiting high activity in alkaline HER. While reports have described the synthesis of NiMo alloys exhibiting diverse HER catalytic activities using morphological control, surface area, porosity, and metal composition, they have shown lower activity than commercial Pt / C alloys. Furthermore, the synthesized NiMo catalysts were utilized as thin films deposited onto substrates, making them unsuitable for application in alkaline anion exchange membrane water electrolysis (AEMWE). Therefore, developing an efficient NiMo catalyst in powder form that exhibits low overpotential and high stability is essential for the commercialization of AEMWE. Generally, permeable structures such as nanorods, nanowires, and nanoneedles can provide a more effective active area for electrode materials, thereby improving material or charge transfer efficiency. Therefore, such morphology engineering is a crucial part of optimal catalyst design. Porous materials derived from metal-organic frameworks (MOFs) have more pores than other catalysts, offering various advantages such as a large surface area and adaptive morphology crucial for catalytic activity. This invention relates to NiMo-MoO2, a catalyst derived from MOFs, for use in HER (Hydrogen-Energy Regeneration) in alkaline line 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, H. H. Liu, Y. Deng, Z. Zhou, J. Yu, H. H. Liu, W. Zhou, Appl. Catal. B Environ. 2019, 249, 98.

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present disclosure aims to provide a method for manufacturing a porous nanorod-shaped NiMo-MoO 3-x alloy that can exhibit excellent HER activity in an alkaline electrolyte, and a water electrolysis cathode catalyst containing the same.

Means for Solving the Problems

[0007] The method for manufacturing a porous nanorod-shaped NiMo-MoO 3-x alloy according to an embodiment of the present invention includes a step of manufacturing a nanorod-shaped NiMo-organic framework body containing molybdenum oxide, nickel salt, and imidazole (step 1); a step of heat-treating the nanorod-shaped NiMo-organic framework body to manufacture a porous nanorod-shaped NiMo oxide (step 2); and a step of subjecting the porous nanorod-shaped NiMo oxide to reduction heat treatment to manufacture a porous nanorod-shaped NiMo-MoO 3-x alloy (step 3).

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

[0009] Moreover, the water electrolysis cathode catalyst of another embodiment of the present invention contains a porous nanorod-shaped NiMo-MoO 3-x alloy, The above-mentioned porous nanorod-shaped NiMo-MoO 3-x alloy has a diameter of 50 to 300 nm and a length of 1 to 5 μm.

Effect of the Invention

[0010] The porous nanorod-shaped NiMo-MoO 3-x alloy produced using a metal-organic framework by the manufacturing method of the present disclosure is porous, has improved conductivity and a high surface area, and is a combination of an alloy and an oxide, and can exhibit excellent HER activity in an alkaline electrolyte when used as a water electrolysis cathode catalyst. In addition, the manufacturing method of the present disclosure can efficiently mass-produce a porous nanorod-shaped NiMo-MoO 3-x alloy.

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1 is a schematic diagram of a method for manufacturing NiMo-MoO3-x porous nanorods using a metal-organic framework according to an embodiment of the present disclosure, and a reaction mechanism for each manufacturing step. [Figure 2] FIG. 2 is a comparison graph of FT-IR (Fourier-transform infrared spectroscopy) of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a comparison graph of BET (Brunauer-Emmett-Teller) of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR according to an embodiment of the present disclosure. [Figure 4]Figure 4 shows a scanning electron microscope (SEM) image of MoO3 (a), a high-resolution transmission electron microscope (HR-TEM) image of Ni-Mo-MOF-NR (b), NiMoO4-PNR (c), and NiMo-MoO3-PNR (d, e) according to one embodiment of the present disclosure, as well as a selected area diffraction (SAED) pattern (f) and energy dispersive analysis X-ray (EDAX) mapping image (g) of NiMo-MoO3-PNR. [Figure 5] Figure 5 shows X-ray diffraction (XRD) pattern images of NiMoO4-PNR according to one embodiment of the present disclosure and NiMo-MoO3-PNR manufactured by changing the heat treatment temperature to 400, 500, 600, 700, and 800°C. [Figure 6] Figure 6 is a comparative graph of X-ray photoelectron spectroscopy (XPS) results obtained by measuring NiMo-MoO3-PNR produced by changing the heat treatment temperature of one embodiment of the present disclosure to 400, 500, 600, 700, and 800°C in Ni-2p and Mo-3d. [Figure 7] Figure 7 is a graph comparing the HER performance of Ni-Mo-MOF-NR, NiMoO4-PNR, NiMo-MoO3-PNR, and NiMo-MoO3 / C-NPNR and Pt / C using linear sweep voltage (LSV) according to one embodiment of the present disclosure. [Figure 8] Figure 8 is a graph comparing the HER performance of NiMo-MoO3-PNR manufactured by changing the heat treatment temperature of one embodiment of the present disclosure to 400, 500, 600, 700, and 800°C, using the Linear Sweep Voltammetry (LSV) method. [Figure 9]Figure 9 is a comparative graph of the Tafel slopes of NiMo-MoO3-PNR and Pt / C produced by changing the heat treatment temperature of one embodiment of the present disclosure to 400, 500, 600, 700, and 800°C. [Figure 10] Figure 10 is a graph comparing the bilayer capacitance of NiMo-MoO3-PNR manufactured by changing the heat treatment temperature of one embodiment of the present disclosure to 400, 500, and 600°C. [Figure 11] Figure 11 is an EIS (Electrochemical Impedance Spectroscopy) comparison graph of NiMo-MoO3-PNR and NiMo-MoO3 / C-NPNR and Pt / C according to one embodiment of the present disclosure. [Figure 12] Figure 12 shows a graph (a) comparing the HER performance of NiMo-MoO3-PNR according to one embodiment of the present disclosure using linear sweep voltammetry (LSV) before and after a 100,000-cycle test, and a graph (b) showing durability tests using chrono-potentiometry, 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 an SEM image of NiMo-MoO3-PNR after 100,000 cycles of testing. [Modes for carrying out the invention]

[0012] In this invention, terms such as "first," "second," etc., are used to describe various components, and are used solely for the purpose of distinguishing one component from other components.

[0013] Furthermore, the terms used herein are used solely to describe exemplary embodiments and are not intended to limit the invention. Unless the context clearly indicates otherwise, singular expressions include plural expressions. In this specification, terms such as “includes,” “equip,” or “have” are intended to specify the existence of implemented features, figures, steps, components, or combinations thereof, and should be understood not to preemptively exclude the existence or possibility of adding one or more other features, figures, steps, components, or combinations thereof.

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

[0015] The present invention can be modified in various ways and may take many forms; therefore, specific embodiments are illustrated and described in detail below. However, this should not be understood as limiting the present invention to any particular disclosure, but rather as including any modifications, equivalents, or substitutions that fall within the spirit and technical scope of the present invention.

[0016] In this disclosure, for convenience of description, the terms “Ni-Mo-MOF-NR” refer to a nanorod-shaped NiMo-organic skeleton, and “NiMoO4-PNR” refer to a porous nanorod-shaped NiMo oxide. 3-x -PNR is a porous nanorod-shaped NiMo-MoO 3-x Alloy, "NiMo-MoO 3-x " / C-NPNR" is NiMo-MoO2 containing a carbon layer in the shape of a non-porous nanorod. 3-x It means alloy.

[0017] The following describes NiMo-MoO according to embodiments of the present invention.3-x This document provides a detailed explanation of the manufacturing method for porous nanorods.

[0018] Porous nanorod-shaped NiMo-MoO of one embodiment of the present invention 3-x The method for manufacturing the alloy is, Step 1: A step to produce a nanorod-shaped NiMo-organic skeleton containing molybdenum oxide, nickel salt, and imidazole; Step 2: Heat-treating the nanorod-shaped NiMo-organic skeleton to produce porous nanorod-shaped NiMo oxide; and The porous nanorod-shaped NiMo oxide is subjected to reducing heat treatment to obtain porous nanorod-shaped NiMo-MoO 3-x Step 3: Manufacturing the alloy; Includes.

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

[0020] In step 1, the molybdenum oxide may be molybdenum dioxide (MoO2) or molybdenum trioxide (MoO3). Preferably, it may be 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 (NiCl2).

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

[0023] In step 1, imidazole acts as a ligand to form complexes with molybdenum oxide and nickel salts, which can be expanded into nanorod-shaped polymers. In particular, the reaction between molybdenum oxide and imidazole is only possible in the presence of nickel salts. This is because, according to the reaction mechanism, the lone electron pair of the two nitrogen atoms of the imidazole molecule is transferred to the molybdenum, forming a covalent bond with the molybdenum oxide, and at this time the two Mo-O - Ni 2+ This is because neutralization is necessary. Therefore, even if the molar ratio of nickel to molybdenum in the precursor mixture changes, the final product is always maintained at a molar ratio of 1:1. This reaction mechanism induces the one-dimensional growth of NiMo-organic skeletons, generating nanorod morphology.

[0024] Step 2 involves heat-treating the nanorod-shaped NiMo-organic skeleton produced in Step 1 in an air atmosphere to thermally decompose the imidazole constituting the organic skeleton, forming a porous structure. This reaction between molybdenum oxide and nickel salt forms 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 may not be sufficiently thermally decomposed, preventing the formation of pores and thus the formation of NiMo oxide. Above 500°C, there is no mass change due to imidazole decomposition, so there is no reason to increase the temperature further.

[0027] Step 3 involves reducing the porous nanorod-shaped NiMo oxide formed in Step 2 by reducing heat treatment, thereby reducing the NiMo oxide and forming porous nanorod-shaped NiMo-MoO 3-x The step involves manufacturing an alloy, and the heat treatment temperature at this time 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 may be 800°C or lower, 750°C or lower, or 700°C or lower.

[0028] In contrast, if the heat treatment temperature is excessively high, phase separation can occur between the Ni3Mo alloy and the single Mo metal, potentially leading to the porous nanorod shape being destroyed into a non-porous state.

[0029] Furthermore, the heat treatment in step 3 may be carried out in a hydrogen and inactive gas mixed atmosphere. Specifically, the inactive gas may be argon.

[0030] The porous nanorod-shaped NiMo-MoO manufactured in step 3 above 3-x The ratio of Mo atoms 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 is Ni 2+ This is only possible when [condition] is met, and as a result, the final product remains fixed at 1:1 even if the molar ratio of Ni to Mo precursors is changed. In this case, oxygen may be present in an amount of 10 to 20% by weight, specifically 15 to 17% by weight.

[0031] Furthermore, one embodiment of the water electrolysis cathode catalyst is a porous nanorod-shaped NiMo-MoO 3-x The alloy contains the porous nanorod-shaped NiMo-MoO 3-xThe alloy may have a diameter of 50 to 300 nm and a length of 1 to 5 μm.

[0032] The aforementioned porous nanorod-shaped NiMo-MoO 3-x The alloy has a porous structure containing pores, and the pores may be 10 to 25 nm in size.

[0033] The aforementioned porous nanorod-shaped NiMo-MoO 3-x The alloy has a surface area of ​​50 to 100 m². 2 / g is also acceptable.

[0034] Porous nanorod-shaped NiMo-MoO included as a water electrolysis cathode catalyst 3-x In alloys, the MoO3 active site is effective in cleaving H-OH bonds, and the NiMo alloy active site has properties that are effective in switching intermediates to H2 molecules. Having a large surface area through a porous structure improves surface contact between the electrode material and the electrolyte, increases the ion transport rate, lowers the charge transfer resistance, and increases the number of active sites, thereby increasing catalytic activity. Therefore, the presence of MoO3 can help increase catalytic activity.

[0035] The following are preferred embodiments for understanding the present invention. However, these embodiments are for illustrative purposes only and do not limit the present invention to them.

[0036] Manufacturing example: Fabrication of porous nanorod-shaped NiMo-MoO3 alloy using MOF (Step 1) 1.0 g of molybdenum oxide (MnO3), 1.63 g of nickel chloride (NiCl2), and 2.67 g of imidazole were placed in a round-bottom flask and dispersed in 200 ml of deionized water, then stirred at room temperature for 5 minutes. The mixture was refluxed in an oil bath at 120°C for 24 hours. The precipitate was collected from the flask, washed with deionized water and ethanol, and then 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 a pale yellow NiMoO4-PNR. (Step 3) 200 mg of the NiMoO4-PNR was heated in a 70% argon, 30% hydrogen atmosphere 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 aforementioned manufacturing example. 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 ratio and atomic ratio in Table 1 below represents the oxygen content.

[0038] [Table 1]

[0039] As shown in Table 1 above, we confirmed that the atomic ratio of Ni to Mo remained 1:1 regardless of the manufacturing step. Furthermore, as shown in Table 2 above, even when the Ni:Mo ratio was changed by varying the concentrations of the initial Ni salt and MoO3 salt, the ratio of Ni to Mo in Ni-Mo-MOF-NR always remained 1:1.

[0040] [Table 2]

[0041] Furthermore, the molecular structure and chemical composition of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR at each step of the manufacturing example were confirmed through FT-IR graphs (Figure 2). In particular, the FT-IR spectrum of Ni-Mo-MOF-NR was obtained at 3430 cm⁻¹. -1 (OH of H2O), 3100-3300 cm -1 (NH / N=H), 2800-3000cm -1 (CH), 1630cm -1 At (C=C), a stretching band exhibiting imidazole properties was observed. This confirmed that imidazole plays a ligand role in MOF formation. The FT-IR spectrum of NiMoO4-PNR showed 807 and 879 cm⁻¹. -1 The Mo-O-Mo bond is 965 cm -1 The Mo=O bond is 633 cm -1 The compound exhibits a characteristic Ni-O bond, and it was confirmed that NiMoO4 is generated from the Ni-Mo-MOF-NR precursor by removing the imidazole skeleton during sintering in air. The FT-IR spectrum of NiMo-MoO3-PNR shows 927, 852, and 578 cm⁻¹. -1 The relatively small peaks correspond to the Mo=O, Mo2-O, and Mo3-O bonds in MoO3, respectively.

[0042] Furthermore, the surface areas of Ni-Mo-MOF-NR, NiMoO4-PNR, and NiMo-MoO3-PNR were confirmed using the 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 m², respectively. 2 g -1 This was confirmed. Furthermore, 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 their pore volumes were 0.05, 0.32, and 0.21 cm³ g, respectively. -1This was confirmed, indicating that Ni-Mo-MOF-NR lacks meaningful porosity. During sintering, mesopores were formed in NiMoO4-PNR by the decomposition of the imidazole skeleton, and this porous structure was maintained even during the thermal reduction of NiMoO4-PNR to NiMo-MoO3-PNR. The large surface area and pore volume of the NiMo-MoO3-PNR catalyst facilitated contact with the electrolyte, which increased catalytic activity by inducing rapid ion transport and improved active site formation.

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

[0044] Figure 4a is an SEM image of the MoO3 used in Step 1. Unlike the NiMo-MoO3-PNR formed in subsequent manufacturing steps, it was confirmed that the MoO3 has a very irregular structure.

[0045] Figure 4b is a TEM image of Ni-Mo-MOF-NR. The image confirms the formation of a smooth nanorod structure.

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

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

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

[0049] Experimental Example 3 NiMo-MoO3-PNR was produced using the same method as the production example, except that NiMoO4-PNR was heat-treated at various temperatures (400, 500, 600, 700, 800°C). The effect of heat treatment temperature on the catalytic properties of NiMo-MoO3-PNR was investigated. Figure 5 shows the XRD patterns of NiMo-MoO3-PNR at different heat treatment temperatures. The sample names based on temperature are indicated as Ni-Mo-x (x: heat treatment temperature). It was confirmed that NiMo peaks were formed at low heat treatment temperatures (400, 500°C), and Ni3Mo peaks were formed at high heat treatment temperatures (600, 700, 800°C). As the heat treatment temperature increased, NiMo-MoO3-PNR underwent phase separation into Mo and Ni3Mo, with Mo and Ni3Mo peaks being mainly formed.

[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, as obtained by 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 are in the same electronic state (Ni 2+ and Mo 6+ It was shown that it possesses ).

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

[0052] [ka]

[0053] Experimental Example 4 Figure 7 is a graph showing the HER performance of the fabricated Ni-Mo-MOF-NR, NiMoO4-PNR, NiMo-MoO3-PNR, and NiMo-MoO3 / C-NPNR with Pt / C, evaluated using linear sweep voltage (LSV) at 1.0 M KOH. NiMo-MoO3 / C-NPNR is a catalyst produced by directly performing step 3 from step 1, without going through the process of carbonizing imidazole in step 2 of Figure 1, to produce non-porous NiMo nanorods. The NiMo-MoO3-PNR catalyst showed higher HER catalytic activity (24.5 mV @ 10 mA cm) compared not only to Ni-Mo-MOF-NR and NiMoO4-PNR, but also to the non-porous NiMo-MoO3 / C-NPNR. -2 ) is quite high, Pt / C (20.1mV@10mA cm -2 It demonstrated performance comparable to that of ).

[0054] Figure 8 shows the LSV of NiMo-MoO3-PNR catalysts produced by heat-treating NiMoO4-PNR at other temperatures (400 to 800°C), as in Experimental Example 3. Here, the NiMo-MoO3-PNR catalyst produced at 500°C showed the highest HER catalytic activity. This is because, in NiMo-MoO3-PNR formed at 500°C, the MoO3 active site is effective in cleaving H-OH bonds, and the NiMo alloy active site has properties that are effective in switching the intermediate to H2 molecules, resulting in excellent HER activity. Furthermore, it is thought that the porosity, crystal structure, and surface area contribute to the excellent HER activity in terms of conductivity.

[0055] Figure 9 is a graph showing the Tafel gradients of NiMo-MoO3-PNR catalysts and NiMo-MoO3 / C-NPNR and Pt / C, produced by heat-treating NiMoO4-PNR at other temperatures (400 to 800°C), as in Experimental Example 3. The Tafel gradient of NiMo-MoO3-PNR produced at 500°C is 32.0 mV dec. -1 Therefore, the lowest Tafel gradient means that HER kinetics increases. Also, non-porous NiMo-MoO3 / C-NPNR (56.4mV dec -1 ) is lower than Pt / C (28.5mV dec -1 It is at a level comparable to that of [another high-end

[0056] The catalytic activity of NiMo-MoO3-PNR produced by the above manufacturing method is shown in Table 3 below, compared to previously reported NiMo catalysts.

[0057] [Table 3]

[0058] According to Table 3 above, the NiMo-MoO3-PNR produced in the example shows that it has superior HER activity compared to previously reported NiMo catalysts due to the synergistic effect between the MoO3 active site and the NiMo alloy active site.

[0059] To obtain electrochemical surface areas (ECSA) using the cyclic voltage-current method (CV), double-layered capacitance (C) is used. dl Figure 10 shows the C of NiMo-MoO3-PNR catalysts produced by heat-treating NiMoO4-PNR at other temperatures (400 to 600°C), as in Experimental Example 3. dl This shows the C of NiMo-MoO3-PNR manufactured at 500℃. dl This is 259.2 mF cm -2 The largest values ​​were 187.4 mF cm at 400°C and 112.2 mF cm at 600°C. -2 And then it appeared. The NiMo-MoO3-PNR example has a higher charge transfer resistance (R) compared to Pt / C. ct ) is the lowest, and non-porous NiMo-MoO3 / C-NPNR is R lower than porous NiMo-MoO3-PNR ct The value was very large (Figure 11). Low R of NiMo-MoO3-PNR ct The value was determined to be due to increased HER catalytic activity resulting from the porous structure and large surface area.

[0060] Experimental Example 5 The stability of NiMo-MoO3-PNR produced by the manufacturing example (Figure 12a) is shown in a graph comparing the stability before and after 100,000 cycle tests, confirming the excellent stability of the catalyst. Since the overpotential of the NiMo-MoO3-PNR in the manufacturing example hardly increased during the cycle tests, it can be seen that the cycle tests have little effect on the decrease in catalytic activity.

[0061] Figure 12b shows NiMo-MoO3-PNRs manufactured by the manufacturing example at different current densities (10, 50, 10 mA cm²). -2This graph shows chrono-potentiometry test results measured over 1 hour, 100 hours, and 1 hour, for a total of 102 hours. Slight fluctuations in voltage were observed during the measurement, which is thought to be due to the repeated accumulation and dispersal of H2 bubbles generated by the HER reaction on the catalyst surface. After 102 hours, the overpotential, as confirmed by the Vt curve, remained almost unchanged. This indicates that the NiMo-MoO3-PNR catalyst possesses excellent electrochemical stability and mechanical hardness.

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

Claims

1. Step 1: To produce a nanorod-shaped NiMo-organic skeleton containing molybdenum oxide, nickel salt, and imidazole; Step 2: Heat-treating the nanorod-shaped NiMo-organic skeleton to produce a porous nanorod-shaped NiMo oxide; and The porous nanorod-shaped NiMo oxide is subjected to reducing heat treatment to produce porous nanorod-shaped NiMo-MoO ３－ｘ Step 3 for manufacturing the alloy; Includes, The above x is 0 or greater and less than 3, and is a porous nanorod-shaped NiMo-MoO ３－ｘ A method for manufacturing alloys.

2. The aforementioned molybdenum oxide is molybdenum trioxide (MoO ３ ) Porous nanorod-shaped NiMo-MoO as described in claim 1 ３－ｘ A method for manufacturing alloys.

3. The aforementioned nickel salt is a nickel halide. Porous nanorod-shaped NiMo-MoO as described in claim 1 ３－ｘ A method for manufacturing alloys.

4. The heat treatment temperature in step 2 is 350 to 600°C. Porous nanorod-shaped NiMo-MoO as described in claim 1 ３－ｘ A method for manufacturing alloys.

5. The above-mentioned porous nanorod-shaped NiMo-MoO ３－ｘ The atomic ratio of Mo to Ni in the alloy is 1:

1. A method for producing a nanorod-shaped NiMo alloy according to claim 1.

6. The heat treatment temperature in step 3 is 500°C or higher. Porous nanorod-shaped NiMo-MoO as described in claim 1 ３－ｘ A method for manufacturing alloys.

7. The heat treatment in step 3 is carried out in a mixed atmosphere of hydrogen and an inactive gas. The manufacturing method of the porous nanorod-shaped NiMo-MoO ３－ｘ ３－ｘ alloy according to Claim 1.

8. Porous nanorod-shaped NiMo-MoO ３－ｘ Contains alloys, The aforementioned 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 aforementioned porous nanorod-shaped NiMo-MoO ３－ｘ The alloy contains pores, The aforementioned pores are of size D ５０ The wavelength is 10 to 25 nm. The water electrolysis cathode catalyst according to claim 8.

10. The aforementioned porous nanorod-shaped NiMo-MoO ３－ｘ The alloy has a surface area of ​​50 to 100 m². ２ / g is The water electrolysis cathode catalyst according to claim 8.

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