KR20210008815A - Water splitting catalyst electrode and manufacturing method for the same - Google Patents

Abstract

The present application relates to a water decomposition catalyst electrode, comprising a porous metal foam, a metal nanowire formed on the surface of the porous metal foam, and a metal double layer hydroxide formed on the surface of the metal nanowire. The water decomposition catalyst electrode can provide a high-performance water decomposition catalyst electrode at a low price, and since the movement speed of electrons during the hydrogen generation reaction is increased, water decomposition efficiency can be increased.

Description

Water decomposition catalyst electrode and its manufacturing method {WATER SPLITTING CATALYST ELECTRODE AND MANUFACTURING METHOD FOR THE SAME}

The present application relates to a water cracking catalyst electrode and a method of manufacturing the same.

Carbon dioxide generated when hydrocarbon materials such as petroleum and coal are combusted is known to affect global warming. This global warming problem is rapidly changing the earth's ecological environment, and this is a problem of human survival, and energy generation technology that does not use hydrocarbon substances is being studied to solve countermeasures against warming.

As resources capable of generating energy without the use of hydrocarbon materials, uranium, sunlight, and hydrogen exist. However, in the case of nuclear power generation using uranium as a raw material, there is a problem that it is difficult to dispose of waste after power generation, and solar power generation using sunlight as an energy source has a disadvantage that is greatly affected by the weather.

In the case of hydrogen, water is required to produce energy, so there is an advantage that there is little risk of resource exhaustion. However, since hydrogen is explosive, it is difficult to store it, and since the process of generating hydrogen by decomposing water requires a lot of energy, studies for storage and generation of hydrogen have been conducted.

The technology behind the present application (Yu, Luo, et al. "Cu Nanowires Shelled with NiFe Layered Double Hydroxide Nanosheets as Bifunctional Electrocatalysts for Overall Water Splitting." Energy & Environmental Science, vol. 10, no. 8, 2017, pp. 1820-1827.) is for Cu nanowires containing a layer of NiFe LDH. This paper discloses a method for decomposing water in a NiFe LDH layer, and does not disclose a method for decomposing water using NiFeP.

The present application is to solve the problems of the prior art described above, and an object thereof is to provide a water decomposition catalyst electrode.

In addition, an object of the present invention is to provide a method of manufacturing the water decomposition catalyst electrode.

In addition, it is an object of the present invention to provide a hydrogen generation method including the water decomposition catalyst electrode.

However, the technical problem to be achieved by the embodiments of the present application is not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above technical problem, the first aspect of the present application includes a porous metal foam, a metal nanowire formed on the surface of the porous metal foam, and a metal double layer hydroxide formed on the surface of the metal nanowire It provides a water decomposition catalyst electrode.

According to the exemplary embodiment of the present disclosure, the metal nanowire may grow vertically from the surface of the porous metal foam, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal double layer hydroxide may grow vertically from the surface of the metal nanowire, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal double layer hydroxide may be phosphorus (P), but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the porous metal foam and the metal nanowire may be surrounded by the metal double layer hydroxide, but are not limited thereto.

According to an exemplary embodiment of the present disclosure, a Tafel slope of the water decomposition catalyst electrode may be 50 mV/dec to 60 mV/dec, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the Faradaic efficiency of the water decomposition catalyst electrode may be 90% to 100%, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal double layer hydroxide includes a first metal and a second metal, and the first metal and the second metal may be different from each other, but are not limited thereto.

According to the exemplary embodiment of the present application, the porous metal foam, the metal nanowire, the first metal, and the second metal are each independently Cu, Ni, Fe, Au, Pt, Ti, Ag, Zr, Ta, Zn, Nb, Cr, Co, Mn, Al, Mg, Si, W, and may include those selected from the group consisting of combinations thereof, but are not limited thereto.

According to an exemplary embodiment of the present disclosure, in the metal double layer hydroxide, the atomic ratio of the first metal and the second metal may be 0.5:1 to 2:1, but is not limited thereto.

In addition, a second aspect of the present application provides a method of manufacturing a water decomposition catalyst electrode comprising forming a metal nanowire on a porous metal foam, and forming a metal double layer hydroxide on the metal nanowire.

According to one embodiment of the present application, the forming of the metal nanowire includes forming a metal hydroxide nanowire on the porous metal foam, and reducing the metal hydroxide nanowire to the metal nanowire. It can be, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, a step of phosphorizing (P) the metal double layer hydroxide may be additionally included, but the present disclosure is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal double layer hydroxide includes a first metal and a second metal, and the first metal and the second metal may be different from each other, but are not limited thereto.

According to one embodiment of the present application, the porous metal foam, the metal nanowire, the first metal and the second metal are each independently Cu, Ni, Fe, Au, Pt, Ti, Ag, Zr, Ta, Zn , Nb, Cr, Co, Mn, Al, Mg, Si, W, and may include those selected from the group consisting of combinations thereof, but are not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal double layer hydroxide may be formed to surround the metal nanowire, but is not limited thereto.

In addition, the third aspect of the present application includes the step of impregnating the water decomposition electrode and the counter electrode according to the first aspect in water and applying a voltage to the water decomposition catalyst electrode and the counter electrode, for a method of generating hydrogen will be.

According to the exemplary embodiment of the present disclosure, the water decomposition catalyst electrode and/or the counter electrode may not be corroded by the water, but is not limited thereto.

The above-described problem solving means are merely exemplary and should not be construed as limiting the present application. In addition to the above-described exemplary embodiments, additional embodiments may exist in the drawings and detailed description of the invention.

According to the above-described problem solving means of the present application, the water decomposition catalyst electrode according to the present application can electrolyze seawater for at least 30 hours or more and photolyze for 45 minutes or more, thereby reducing the overall cost of the system for mass-producing hydrogen. I can make it.

In addition, the water decomposition catalyst electrode according to the present application uses inexpensive non-noble metal elements such as Cu, Ni, Fe, and P, and the water decomposition catalyst electrode may have superior performance than a platinum catalyst. Accordingly, the water cracking catalyst electrode can provide a high performance water cracking catalyst electrode at an inexpensive price.

In addition, the water decomposition catalyst electrode according to the present application includes a printed metal double-layer hydroxide formed on a highly conductive metal nanowire, so that the transfer rate of electrons during the hydrogen generation reaction is accelerated, and thus water decomposition efficiency can be increased. .

In addition, the water decomposition catalyst electrode according to the present application can electrolyze not only fresh water but also seawater, and does not corrode well compared to general electrodes, and chlorine, which may occur during electrolysis of seawater, may not be discharged.

In addition, the method of manufacturing a water decomposition catalyst electrode according to the present application is not limited to the size of an area, and a wide electrode can be easily manufactured.

However, the effect obtainable in the present application is not limited to the effects as described above, and other effects may exist.

1 is a schematic diagram of a water decomposition catalyst electrode according to an embodiment of the present application.
2 is a flow chart showing a method of manufacturing a water decomposition catalyst electrode according to an embodiment of the present application.
3 is a schematic diagram showing a method of manufacturing a water decomposition catalyst electrode according to an embodiment of the present application.
4 is a schematic diagram of a hydrogen generation method according to an embodiment of the present application.
5 is a FESEM image of a step of manufacturing a water decomposition catalyst electrode according to an embodiment of the present application.
6 is a photograph of a step of manufacturing a water decomposition catalyst electrode according to an embodiment of the present application.
7 is an XRD pattern of a water decomposition catalyst electrode according to an embodiment of the present application.
8 is a TEM image of a water decomposition catalyst electrode according to an embodiment of the present application.
9 is an EDS pattern of a water decomposition catalyst electrode according to an embodiment of the present application.
10 is a HAADF-STEM mapping result of a water decomposition catalyst electrode according to an embodiment of the present application.
11 is a result of XPS spectrum analysis before and after Ar treatment of Cu, Ni, Fe, and P of the water decomposition catalyst electrode according to an embodiment of the present application.
Figure 12 (a) is for the HER polarization curve (Hydrogen evolution reaction polarization curve) of the water decomposition catalyst electrode according to an embodiment and a comparative example of the present application, (b) is a water decomposition according to Example 1 and Comparative Example Tafel plot of the catalyst electrode, (c) is a Nyquist plot of the water decomposition catalyst electrode according to Example 1 and Comparative Example, (d) is the Example 1 and Comparative Example LSV curve (Linear Sweep Voltammetry curve) of the water decomposition catalyst electrode according to, (e) is a photograph of the water decomposition catalyst electrode according to Example 1.
13 (a) shows the relationship between the overvoltage and current density of the water decomposition catalyst electrode according to an embodiment and a comparative example of the present application, and (b) and (c) are according to Example 1 and Comparative Example. It is a graph showing the performance of the water cracking catalyst electrode.
14 is a graph showing (a) voltage and (b) cell voltage over time of a water decomposition catalyst electrode according to an embodiment and a comparative example of the present application.
15 is a graph showing the performance of a water decomposition catalyst electrode according to an embodiment and a comparative example of the present application.
16 is a graph showing the cell voltage over time of the water cracking catalyst electrode according to an embodiment of the present application.
Figure 17 (a) is a UV-vis spectrum of the water decomposition catalyst electrode according to the standard control test of the present application, (b) is a graph showing the HClO concentration at the specific absorption peak of (a).
(A) of FIG. 18 is a UV-vis spectrum according to the salt concentration of water impregnated with a water decomposition catalyst electrode according to an embodiment of the present application, and (b) is of OCl ^- at a specific absorption peak of (a) A graph showing the concentration, (c) is a graph between the voltage applied to the water decomposition catalyst electrode according to Example 1 and the wavelength of the irradiated light, and (d) is the water decomposition catalyst electrode according to Example 1 This is a graph comparing the hydrogen generation rate with the theoretical value.
19 is a photograph for comparing the amount of hydrogen and oxygen produced by the water cracking catalyst electrode according to an embodiment of the present application.
20 is a photograph taken of a hydrogen generation method according to an embodiment of the present application.
21 is a graph showing the operation of the hydrogen generation method according to an embodiment of the present application.

Hereinafter, exemplary embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present application.

However, the present application may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts not related to the description are omitted in order to clearly describe the present application, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the present specification, when a part is said to be "connected" with another part, this includes not only the case that it is "directly connected", but also the case that it is "electrically connected" with another element interposed therebetween. do.

Throughout this specification, when a member is positioned "on", "upper", "upper", "under", "lower", and "lower" of another member, this means that a member is located on another member. It includes not only the case where they are in contact but also the case where another member exists between the two members.

Throughout the specification of the present application, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

As used herein, the terms "about", "substantially" and the like are used at or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and to aid understanding of the present application In order to prevent unreasonable use by unscrupulous infringers of the stated disclosure, exact or absolute numerical values are used. In addition, throughout the specification of the present application, "step to" or "step of" does not mean "step for".

In the entire specification of the present application, the term "combination of these" included in the expression of the Makushi format refers to one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Makushi format, and the component It means to include one or more selected from the group consisting of.

Throughout this specification, the description of "A and/or B" means "A or B, or A and B".

Hereinafter, the water decomposition catalyst electrode of the present application and a method of manufacturing the same will be described in detail with reference to embodiments and examples and drawings. However, the present application is not limited to these embodiments and examples and drawings.

As a technical means for achieving the above technical problem, the first aspect of the present application is a porous metal foam 100, a metal nanowire 200 formed on the surface of the porous metal foam 100, and the metal nano It provides a water decomposition catalyst electrode 10 including a metal double layer hydroxide 300 formed on the surface of the wire 200.

1 is a schematic diagram of a water decomposition catalyst electrode according to an embodiment of the present application.

In this regard, as will be described later, the metal double layer hydroxide 300 of the water decomposition catalyst electrode 10 is phosphorus (P), and the non-flammable metal double layer hydroxide 400 is used to prepare the metal double layer hydroxide 300 It means a substance located in the intermediate stage for. Herein, unless otherwise specified, the description of “metal bilayer hydroxide” refers to a material included in the water cracking catalyst electrode 10, phosphorus (P), and referred to as 300 in FIG. 1.

Referring to FIG. 1, the water decomposition catalyst electrode 10 may reduce water (H ₂ O) to hydrogen (H ₂ ) through the metal double layer hydroxide 300.

The porous metal foam 100 according to the present application refers to a porous metal material having open or closed pores, and corresponds to the substrate of the water decomposition catalyst electrode 10. The porous metal foam 100 is for fixing the shape of the metal nanowire 200 and the metal double layer hydroxide 300 and supplying electrons.

According to the exemplary embodiment of the present disclosure, the porous metal foam 100 may include pores of 1 μm to 10 μm, but is not limited thereto. For example, the porous metal foam 100 is about 1 μm to about 10 μm, about 2 μm to about 10 μm, about 3 μm to about 10 μm, about 4 μm to about 10 μm, about 5 μm to about 10 μm, about 6 μm to about 10 μm, about 7 μm to about 10 μm, about 8 μm to about 10 μm, about 9 μm to about 10 μm, about 1 μm to about 2 μm, about 1 μm to about 3 μm, About 1 μm to about 4 μm, about 1 μm to about 5 μm, about 1 μm to about 6 μm, about 1 μm to about 7 μm, about 1 μm to about 8 μm, about 1 μm to about 9 μm, about 2 μm to about 9 μm, about 3 μm to about 8 μm, about 4 μm to about 7 μm, about 5 μm to about 6 μm, about 6 μm to about 10 μm, about 7 μm to about 10 μm, about 8 μm to About 10 μm, about 2 μm to about 8 μm, about 2 μm to about 7 μm, about 2 μm to about 6 μm, about 2 μm to about 5 μm, about 2 μm to about 4 μm, about 2 μm to about 3 μm, about 3 μm to about 7 μm, about 3 μm to about 6 μm, about 3 μm to about 5 μm, about 3 μm to about 4 μm, about 4 μm to about 6 μm, or about 4 μm to about 5 μm It may include pores of, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal nanowire 200 may grow on the pores of the porous metal foam 100, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the metal nanowire 200 may grow vertically from the surface of the porous metal foam 100, but is not limited thereto.

The metal nanowire 200 according to the present application is made of a metal element, has a diameter of nanometers, and a length of nanometers or micrometers or more. The metal nanowire 200 may be formed on the porous metal foam 100 to supply electrons to the metal double layer hydroxide 300.

According to the exemplary embodiment of the present disclosure, the metal double-layer hydroxide 300 may grow vertically from the surface of the metal nanowire 200, but is not limited thereto.

In this regard, the base material that the metal nanowire 200 has grown vertically from the surface of the porous metal foam 100, the angle between the metal nanowire 200 and the porous metal foam 100 is 70° It means that it is 90°, and this can be equally applied to the relationship between the metal double layer hydroxide 300 and the metal nanowire 200.

According to the exemplary embodiment of the present disclosure, the porous metal foam 100 and the metal nanowire 200 may be surrounded by the metal double layer hydroxide 300, but are not limited thereto.

The metal nanowire 200 is formed to increase the surface area of the porous metal foam 100, and the metal double-layer hydroxide 300 is formed to increase the surface area of the porous metal foam 100 and the metal nanowire 200. , The surfaces of the porous metal foam 100 and the metal nanowire 200 may be surrounded by the metal double layer hydroxide 300 so as not to contact water.

According to the exemplary embodiment of the present disclosure, the metal nanowire 200 may have a length of 10 μm to 20 μm, but is not limited thereto.

When the metal nanowire 200 has a length of less than 20 μm, the metal double layer hydroxide 300 may not grow sufficiently, so that the porous metal foam 100 may be corroded or abraded by water. If it has a length, the rate of supplying electrons to the metal double layer hydroxide 300 may be reduced.

According to the exemplary embodiment of the present disclosure, the metal double-layer hydroxide 300 may have a thickness of 10 nm to 20 nm, but is not limited thereto.

When the metal double-layer hydroxide 300 has a thickness of more than 20 nm, the hydrogen generation efficiency of the water decomposition catalyst electrode 10 may be reduced, and when it has a thickness of less than 10 nm, the porous metal foam 100 And the metal nanowire 200 may be corroded or worn by water.

According to the exemplary embodiment of the present disclosure, the metal double-layer hydroxide 300 may be printed, but is not limited thereto.

According to an exemplary embodiment of the present disclosure, a Tafel slope of the water decomposition catalyst electrode may be 50 mV/dec to 60 mV/dec, but is not limited thereto.

The Tafel curve slope according to the present application is for activation potential η and current density J, and exchange current density J ₀ , and may be expressed as A in Equation 1 below.

[Equation 1]

η = A ln(J/J ₀ )

The smaller the slope A of the Tafel curve means that the hydrogen generation reaction is active.

According to the exemplary embodiment of the present disclosure, the Faradaic efficiency of the water decomposition catalyst electrode may be 90% to 100%, but is not limited thereto.

The Faradaic efficiency according to the present application defines the reduction efficiency for a specific product in terms of electron transfer, and can be expressed as ε _Faradaic in Equation 2 below.

[Equation 2]

ε _Faradaic = znF/Q

In Equation 2, z is the number of electrons required for the exchange calculated through the reaction equation, n is the number of moles of the desired product, F is the Faraday constant (1 F = 96485 C/mol), and Q is the charged charge Is the amount of

Since the Faraday efficiency is a ratio of the current consumed to produce a specific product, the efficiency of the hydrogen generation reaction can be confirmed through the Faraday efficiency.

According to the exemplary embodiment of the present disclosure, the metal double-layer hydroxide 300 includes a first metal and a second metal, and the first metal and the second metal may be different from each other, but are not limited thereto.

According to the exemplary embodiment of the present application, the porous metal foam 100, the metal nanowire 200, the first metal, and the second metal are each independently Cu, Ni, Fe, Au, Pt, Ti, Ag, Zr, Ta, Zn, Nb, Cr, Co, Mn, Al, Mg, Si, W, and may include those selected from the group consisting of combinations thereof, but are not limited thereto.

According to an exemplary embodiment of the present disclosure, in the metal double-layer hydroxide 300, the atomic ratio of the first metal and the second metal may be 0.5:1 to 2:1, but is not limited thereto. In this regard, the atomic ratio means the ratio of moles.

For example, the metal double layer hydroxide 300 may include NiP ₂ and FeP ₂ , but is not limited thereto. The ratio of P may vary depending on the degree to which the Ni and/or Fe is ignited.

According to the exemplary embodiment of the present disclosure, the water decomposition catalyst electrode 10 may be bent, but is not limited thereto.

Since the general double-layer metal hydroxide 300 is a ceramic material, it is known to be brittle and fracture brittle when bent. However, the metal double layer hydroxide 300 according to the present application is formed perpendicular to the surface of the metal nanowire 200, the metal nanowire 200 is formed perpendicular to the surface of the porous metal foam 100, the Since the porous metal foam 100 is generally made of a metal material having ductility, the water decomposition catalyst electrode 10 may be bent by the ductility of the porous metal foam 100.

According to the exemplary embodiment of the present disclosure, the impedance of the water decomposition catalyst electrode 10 may be 0.25 Ω or less, but is not limited thereto.

As will be described later, since the conventional water decomposition catalyst electrode has an impedance of 0.5 Ω or more, the rate at which electrons move from the porous metal foam 100 to the metal double layer hydroxide 300 is slow, and thus hydrogen generation efficiency is low. However, the water decomposition catalyst electrode 10 according to the present application has a lower impedance than the conventional water decomposition catalyst electrode, and thus hydrogen generation efficiency can be improved.

In addition, the second aspect of the present application comprises forming a metal nanowire 200 on the porous metal foam 100, and forming a metal double layer hydroxide 300 on the metal nanowire 200 , To provide a method of manufacturing a water decomposition catalyst electrode 10

With respect to the method of manufacturing the water decomposition catalyst electrode according to the second aspect of the present application, detailed descriptions of parts overlapping with the first aspect of the present application have been omitted, but even if the description is omitted, the content described in the first aspect of the present application The same can be applied to the second aspect of

According to the exemplary embodiment of the present disclosure, the method of manufacturing the water decomposition catalyst electrode 10 may further include a step of igniting the metal double layer hydroxide 400, but is not limited thereto.

The non-flammable metal double layer hydroxide 400 may be converted into the metal double layer hydroxide 300 by phosphorus (P).

That is, the method of manufacturing the water decomposition catalyst electrode 10 according to the present application is a step of forming a metal nanowire 200 on the porous metal foam 100, phosphorus (P) on the metal nanowire 200 Forming the non-phosphorous metal double layer hydroxide 400, and the step of forming the metal double layer hydroxide 300 by igniting the non-phosphorous (P) metal double layer hydroxide 400, but is limited thereto. It is not.

2 is a flowchart of a method of manufacturing a water decomposition catalyst electrode according to an embodiment of the present application, and FIG. 3 is a schematic diagram of a method of manufacturing a water decomposition catalyst electrode according to an exemplary embodiment of the present application.

First, a metal nanowire 200 is formed on the porous metal foam 100 (S100).

According to an exemplary embodiment of the present application, the forming of the metal nanowire 200 includes forming a metal hydroxide nanowire (not shown) on the porous metal foam 100, and the metal hydroxide nanowire ( (Not shown) may include the step of reducing to the metal nanowire 200, but is not limited thereto.

Typical metal nanowires are formed by mixing two or more solvents having different reducing powers, adding capping agents having different molecular weights to the solvent, and then adding a catalyst and a metal oxide to the solvent.

The metal nanowire 200 according to the present application includes forming a metal hydroxide nanowire (not shown) on the porous metal foam 100, oxidizing the metal hydroxide nanowire into a metal oxide nanowire, and the It may be manufactured by reducing the metal oxide nanowire to the metal nanowire 200, but is not limited thereto.

For example, when the metals of the porous metal foam 100 and the metal nanowire 200 are both Cu, Cu(OH) ₂ nanowires may be formed from the porous Cu by a chemical oxidation method. have. The Cu(OH) ₂ nanowires may be converted into CuO nanowires by firing, and the CuO nanowires may be electrochemically reduced to become Cu nanowires.

The metal nanowire 200 may reduce water by supplying electrons to the metal double layer hydroxide 300.

Subsequently, a metal double-layer hydroxide 300 is formed on the metal nanowire 200 (S200).

According to an exemplary embodiment of the present disclosure, the forming of the metal double layer hydroxide 300 includes forming a metal double layer hydroxide 400 that is not phosphorus (P) on the metal nanowire (S210) and the printing The step of igniting the non-metal double layer hydroxide 400 (S220) may be included, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the double metal hydroxide 300 may be formed to surround the metal nanowire 200, but is not limited thereto. In this regard, the non-flammable metal double layer hydroxide 400 may also be formed to surround the metal nanowire 200, but is not limited thereto.

As described above, the layered double hydroxide included in the water decomposition catalyst electrode 10 is phosphorus (P) completed, but the phosphorus metal double layer hydroxide 300 on the metal nanowire 200 It is known to be difficult to form. Therefore, in the present application, after forming the non-flammable metal double layer hydroxide 400 on the metal nanowire 200, the water decomposition catalyst electrode 10 is ignited by igniting the metal double layer hydroxide 400 The water decomposition catalyst electrode 10 was formed to include the metal double layer hydroxide 300 and the fired metal double layer hydroxide 300 improves the conductivity, and the number of active sites for hydrogen generation increases. , Life can be improved.

According to the exemplary embodiment of the present disclosure, the metal double-layer hydroxide 300 or 400 includes a first metal and a second metal, and the first metal and the second metal may be different from each other, but are not limited thereto.

When the metal double-layer hydroxide 300 or 400 includes two or more different metals, hydrogen generation efficiency may be improved as compared to a metal hydroxide including one type of metal. In addition, in the case of the metal double layer hydroxide 300 including two or more types of metal phosphide, it can be seen that the decomposition of water is accelerated compared to the metal hydroxide including one type of metal phosphide or the non-flammable metal double layer hydroxide 400. .

According to one embodiment of the present application, the porous metal foam 100, the metal nanowire 200, the first metal and the second metal are each independently Cu, Ni, Fe, Au, Pt, Ti, Ag , Zr, Ta, Zn, Nb, Cr, Co, Mn, Al, Mg, Si, W, and may include those selected from the group consisting of combinations thereof, but are not limited thereto.

In addition, the third aspect of the present application is the step of impregnating the water decomposition electrode 10 and the counter electrode 20 according to the first aspect in water, and the voltage to the water decomposition catalyst electrode 10 and the counter electrode 20 It relates to a method of generating hydrogen, including applying.

4 is a schematic diagram of a hydrogen generation method according to an embodiment of the present application.

With respect to the hydrogen generation method according to the third aspect of the present application, detailed descriptions of portions overlapping with the first and second aspects of the present application have been omitted, but even if the description is omitted, the first aspect and/or the second aspect of the present application The content described in the side can be equally applied to the third aspect of the present application.

According to the exemplary embodiment of the present disclosure, the hydrogen generation method may be operated by sunlight, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the counter electrode 20 may include the non-flammable metal double-layer hydroxide 400, but is not limited thereto. For example, the counter electrode 20 may include a non-flammable metal double-layer hydroxide 400 formed on the porous metal foam 100, but is not limited thereto.

According to the exemplary embodiment of the present disclosure, the water decomposition catalyst electrode 10 and/or the counter electrode 20 may not be corroded by the water, but is not limited thereto.

The water decomposition catalyst electrode 10 and/or the counter electrode 20 according to the present application includes the metal double layer hydroxide (300 or 400) on the surface, so that it can be operated in seawater as well as fresh water, and hydrogen in the seawater It may not corrode when producing.

According to the exemplary embodiment of the present disclosure, the method of generating hydrogen may not release chlorine (Cl ₂ ), but is not limited thereto.

In general, since seawater contains NaCl, a problem in that chlorine (Cl ₂ ) is formed instead of oxygen is formed at the anode of the hydrogen generation method may occur. Specifically, in the anode of a general hydrogen generation method using seawater, HClO and OCl ^- ions may be formed together with oxygen evolution reaction (OER) to form Cl ₂ . The HClO and OCl ^- ions can be detected by an o-tolidine solution.

However, hydrogen generation according to the present application may be performed by using the water decomposition catalyst cathode electrode 10.

The present invention will be described in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[Example 1]

After washing the porous Cu foam with 37% HCl, it was sonicated with ethanol and deionized water. Subsequently, the porous Cu foam was impregnated in 14 ml of an aqueous solution containing 1.05 g of NaOH and 300 mg of (NH ₄ ) ₂ S ₂ O ₈ for 30 minutes. When the porous Cu foam had a blue light, it was washed several times with deionized water and then dried in air to form Cu(OH) ₂ nanowires. The Cu(OH) ₂ nanowires were heat-treated at 180° C. for 1 hour to form CuO nanowires, and the CuO nanowires had a voltage of -1.08 V vs Ag/AgCl in 1 M NaHCO ₃ aqueous solution saturated with Ar. Applied and reduced to Cu nanowires.

Subsequently, the porous Cu foam with the Cu nanowires formed was -1.2 V vs Ag using 50 ml of an electrolyte containing 0.04 M Ni(NO ₃ ) ₂ ·6H2O and 0.04 M Fe(NO ₃ ) ₃ · 9H ₂ O. By electro-deposition by the voltage of /AgCl, the intermediate material NiFe-LDH/Cu NW/Cu Foam was formed.

The intermediate material was reacted with NaPO ₂ H ₂ at 350° C. for 2 hours in an Ar atmosphere to form NiFeP/Cu NW/Cu Foam (hereinafter, a water decomposition catalyst electrode).

5 is a FESEM image of a step of manufacturing the water decomposition catalyst electrode according to Example 1. Specifically, (a) of FIG. 5 is a porous Cu foam, (b) is a Cu(OH) ₂ nanowire formed on the porous Cu foam, and (c) is a Cu nanowire formed on the porous Cu foam ( Cu NW/Cu Foam), (d) is NiFe-LDH formed on the Cu NW/Cu Foam, and (e) is an SEM image of NiFeP/Cu NW/Cu Foam.

6 is a photograph of a step of manufacturing the water decomposition catalyst electrode according to Example 1, FIG. 7 is an XRD pattern of the water decomposition catalyst electrode according to Example 1, and FIG. 8 is a water decomposition catalyst electrode according to Example 1 9 is an EDS pattern of the water cracking catalyst electrode according to Example 1, FIG. 10 is a HAADF-STEM mapping result of the water cracking catalyst electrode according to Example 1, and FIG. 11 is the example It is the XPS spectrum analysis result before and after Ar treatment of Cu, Ni, Fe, and P of the water decomposition catalyst electrode according to 1. Specifically, (a) of Figure 6 is a porous Cu foam, (b) is a Cu(OH) ₂ nanowire/porous Cu foam, (c) is a Cu NW/Cu Foam, and (d) is a NiFeP/Cu It is NW/Cu Foam.

6 to 11, the water decomposition catalyst electrode may be bent, and NiP ₂ and FeP ₂ are bound to NiFeP, and the composition ratio of the NiFeP is Ni: Fe: P = 1.17: 1: 1.96. I can.

[Example 2]

After impregnating the water decomposition catalyst electrode (NiFeP/Cu NW/Cu Foam) according to Example 1 as a (-) pole, and the NiFe-LDH/Ni Foam as a (+) pole, in a 1 M KOH solution at 25° C. , Connected to the power supply.

[Example 3]

The same as in Example 2, but instead of the 1 M KOH solution at 25 ℃ 1 M KOH and 0.6 M NaCl solution (seawater) at 25 ℃ was used.

[Example 4]

Same as in Example 2, but the temperature of the KOH solution was set to 100°C.

[Example 5]

Same as in Example 3, but the temperature of seawater was set to 100°C.

[Comparative Example 1]

CFP (Carbon fiber paper) was used as a water decomposition catalyst electrode,

[Comparative Example 2]

Cu foam was used as a water decomposition catalyst electrode.

[Comparative Example 3]

NiFeP/CFP was used as a water decomposition catalyst electrode.

[Comparative Example 4]

20 wt% Pt/C/Cu foam was used as a water cracking catalyst electrode.

[Comparative Example 5]

This is a method of generating hydrogen by including the electrode of Comparative Example 4 as a (-) pole, and including RuO ₂ /Ni foam as a (+) pole.

[Experimental Example 1]

Figure 12 (a) is for the HER polarization curve (Hydrogen evolution reaction polarization curve) of the water decomposition catalyst electrode according to the Examples and Comparative Examples, (b) is the water decomposition catalyst electrode according to the Examples and Comparative Examples. Tafel plot, (c) is a Nyquist plot of a water cracking catalyst electrode according to Examples and Comparative Examples, and (d) is a water cracking catalyst according to Examples and Comparative Examples. It is the LSV curve (Linear Sweep Voltammetry curve) of the electrode, and (e) is a photograph of the water decomposition catalyst electrode according to the embodiment.

Referring to FIG. 12, the NiFeP/Cu NW/Cu foam has a high current density even when a low voltage is applied, has a Tafel slope of 50 mV/dec to 60 mV/dec, and has a low impedance, so that the water decomposition catalyst It can be excellent as an electrode. In general, a catalyst electrode having a high impedance has a slow charge transfer rate, so it is necessary to reduce the impedance as much as possible in order to use it for a water cracking catalyst electrode. The NiFeP/Cu NW/Cu Foam electrode according to the present application has a low impedance and a high charge transfer rate compared to a conventional water decomposition catalyst electrode.

[Experimental Example 2]

13 (a) shows the relationship between the overvoltage and current density of the water cracking catalyst electrode according to the Examples and Comparative Examples, and (b) and (c) are the water cracking catalysts according to the Examples and Comparative Examples. A graph showing the performance of the electrode, FIG. 14 is a graph showing the current density of the water cracking catalyst electrode according to the Examples and Comparative Examples over time, and FIG. 15 is a graph showing the current density of the water cracking catalyst electrode according to the Examples and Comparative Examples. It is a graph showing the performance, and FIG. 16 is a graph showing the current density over time of the water decomposition catalyst electrode according to the embodiment.

13, the NiFeP/Cu NW/Cu Foam requires a low level of overpotential and cell voltage to achieve a specific current density, and a 1 M KOH solution at 100° C., 100° C. It can be seen that the performance is improved in seawater of and 25°C.

14 to 16, the NiFeP/Cu NW/Cu Foam requires a lower level of cell voltage compared to the conventional technology in order to achieve a certain level of current density, and a cell voltage of 3 V or more is applied. Even if it is, hydrogen can be produced.

[Experimental Example 3]

Figure 17 (a) is a UV-vis spectrum of the water decomposition catalyst electrode according to the standard control test, (b) is a graph showing the HClO concentration at the specific absorption peak of (a), Figure 18 (a) Is for the UV-vis spectrum according to the salt concentration of water impregnated with the water decomposition catalyst electrode according to the above embodiment, (b) is a graph showing the concentration of OCl ^- at the specific absorption peak of (a), (c ) Is a graph between the voltage applied to the water decomposition catalyst electrode according to the above embodiment and the wavelength of the irradiated light, and (d) is a graph comparing the hydrogen generation degree of the water decomposition catalyst electrode according to the embodiment with a theoretical value to be.

17 and 18, even when a cell voltage of 2.6 V was continuously applied for 1 hour, HClO ions and/or OCl ions were not detected in the seawater, which is NiFeP/Cu NW/Cu Foam and NiFe -It proves that LDH/Ni Foam has a high level of oxygen and hydrogen selectivity.

[Experimental Example 4]

19 is a photograph for comparing the amount of hydrogen and oxygen generated by the water decomposition catalyst electrode according to the above embodiment, FIG. 20 is a photograph taken of the hydrogen generation method according to the above embodiment, and FIG. 21 is the embodiment It is a graph showing the operation of the hydrogen generation method according to the example. Specifically, FIG. 20 is a photograph of a water decomposition reaction using seawater and solar cells.

19 to 21, the hydrogen generation method according to the present disclosure may generate hydrogen even by a solar cell having an efficiency of 26.53%, and an efficiency of η _StH (solar to hydrogen) may be 19.85%. In addition, since the hydrogen generation method including NiFeP/Cu NW/Cu Foam can maintain the same current density for at least 45 minutes, hydrogen can be stably produced, and O ₂ has a Faraday efficiency of 99.3%, and H _In case ₂ , water can be decomposed to have a Faraday efficiency of 99.2%.

The foregoing description of the present application is for illustrative purposes only, and those of ordinary skill in the art to which the present application pertains will be able to understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present application is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present application.

10: water decomposition catalyst electrode
100: porous metal foam
200: metal nanowire
300: phosphorus (P) metal double layer hydroxide
400: Non-phosphorous (P) metal double layer hydroxide
20: counter electrode

Claims (18)

Porous metal foam;
Metal nanowires formed on the surface of the porous metal foam; And
A metal double layer hydroxide formed on the surface of the metal nanowire;
Containing,
Water cracking catalyst electrode.
The method of claim 1,
The metal nanowires are grown vertically from the surface of the porous metal foam, water decomposition catalyst electrode.
The method of claim 1,
The metal double layer hydroxide is grown vertically from the surface of the metal nanowire, water decomposition catalyst electrode.
The method of claim 1,
The metal double layer hydroxide is phosphorus (P) is, water decomposition catalyst electrode.
The method of claim 1,
The porous metal foam and the metal nanowires have the metal double layer hydroxide, water decomposition catalyst electrode.
The method of claim 1,
The Tafel slope of the water decomposition catalyst electrode is 10 mV/dec to 100 mV/dec, the water decomposition catalyst electrode.
The method of claim 1,
The water cracking catalyst electrode has a Faradaic efficiency of 1% to 100%.
The method of claim 1,
The metal double-layer hydroxide includes a first metal and a second metal, and the first metal and the second metal are different from each other.
The method of claim 8,
The porous metal foam, the metal nanowire, the first metal, and the second metal are each independently Cu, Ni, Fe, Au, Pt, Ti, Ag, Zr, Ta, Zn, Nb, Cr, Co, Mn, Al, Mg, Si, W, and a water decomposition catalyst electrode comprising one selected from the group consisting of combinations thereof.
The method of claim 8,
In the metal double layer hydroxide, the atomic ratio of the first metal and the second metal is 0.5:1 to 2:1, the water decomposition catalyst electrode.
Forming metal nanowires on the porous metal foam; And
Forming a metal double layer hydroxide on the metal nanowire;
Containing,
Method for producing a water cracking catalyst electrode.
The method of claim 11,
The forming of the metal nanowire includes forming a metal hydroxide nanowire on the porous metal foam, and reducing the metal hydroxide nanowire to the metal nanowire. Manufacturing method.
The method of claim 11,
The method of manufacturing a water decomposition catalyst electrode further comprising the step of phosphorus (P) the metal double layer hydroxide.
The method of claim 11,
The metal double-layer hydroxide includes a first metal and a second metal, and the first metal and the second metal are different from each other.
The method of claim 14,
The porous metal foam, the metal nanowire, the first metal and the second metal are each independently Cu, Ni, Fe, Au, Pt, Ti, Ag, Zr, Ta, Zn, Nb, Cr, Co, Mn , Al, Mg, Si, W, and a method of manufacturing a water decomposition catalyst electrode comprising those selected from the group consisting of combinations thereof.
The method of claim 11,
The metal double layer hydroxide is formed to surround the metal nanowires, the method of manufacturing a water decomposition catalyst electrode.
Impregnating the water decomposition catalyst electrode and the counter electrode according to any one of claims 1 to 10 in water; And
Applying a voltage to the water decomposition catalyst electrode and the counter electrode;
Including
Hydrogen generation method.
The method of claim 17,
The water decomposition catalyst electrode and/or the counter electrode is not corroded by the water.

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