In-situ nano composite hydrogen evolution material

Abstract

The invention provides an in-situ nano composite hydrogen evolution material which is characterized in that foamed nickel is used as a base material, a core-shell structure is attached to the surface of the composite hydrogen evolution material, a core is a sulfurized NbMn nanowire with the diameter of 30-60 nm, a shell is carbonized MoMn with the thickness of 10-50 nm, efficient electro-catalytic hydrogen production performance is shown, particularly, the in-situ nano composite hydrogen evolution material has ultrahigh stability, and the in-situ nano composite hydrogen evolution material is suitable for hydrogen evolution of hydrogen production. Good application prospects are realized in the fields of energy conversion and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrocatalytic material preparation, and particularly relates to an in-situ nano-composite hydrogen evolution material and application thereof as a full water-splitting cathode. BACKGROUND

[0002] Nowadays, "energy crisis" has become the focus of attention in the global range. Power outage, rising oil prices and other factors affect our daily life. In addition, the burning of fossil fuels releases various greenhouse gases, such as carbon dioxide, nitrogen oxides and sulfur oxides, which will cause serious environmental problems. From the perspective of sustainable development of human society, solving energy crisis and greenhouse effect must start from developing renewable and clean new energy. As we all know, the sun contains endless energy. The energy of 80 minutes of sunlight on the earth (∼5.73×10 20 J) is approximately equal to the total energy consumed by the earth in 2020. But solar energy itself is not conducive to collection and storage, and like wind and water energy, it is affected by natural conditions and geographical location, and has certain intermittency, volatility and limitations.

[0003] Hydrogen, as an ideal energy carrier, has the highest energy density among all chemical fuels. High-energy zero-carbon, non-toxic and easy-to-transport unique advantages make it have considerable application prospect, and the rapid development of hydrogen fuel cell vehicles, chemical industry, machinery manufacturing, aerospace, agriculture and other fields cannot be separated from the supply of hydrogen energy, and the demand for hydrogen energy is also increasing. At the same time, with the attention of human beings to hydrogen energy, the global "hydrogen industry" is developing rapidly, and the hydrogen production technology is also being optimized and innovated. Green and environmentally friendly water decomposition hydrogen production method conforms to the concept of sustainable development and is explored more. In thermodynamics, the enthalpy required for water decomposition into hydrogen and oxygen at room temperature and pressure is 286 kJ mol -1 , and the energy supply can come from solar energy and electricity, and the production methods correspond to solar thermal decomposition hydrogen production / photocatalytic hydrogen production and electrocatalytic hydrogen production. Solar thermal decomposition hydrogen production requires heating water to a high temperature of 3000K or more, which requires extremely harsh equipment and high cost, which to some extent limits its large-scale use. Photocatalytic hydrogen production has high demand for catalysts and light sources, and most catalysts have poor stability in the visible light region and low activity, and only rely on natural sunlight, which is too low in efficiency, and long-term irradiation can easily cause corrosion of the catalyst. Electrolysis of water is considered to be the most reliable, economical and convenient method of hydrogen production, which is not limited by conditions such as location and time, and can produce high-purity hydrogen gas immediately. With the large-scale application of hydrogen energy and the continuous development of science and technology society, regional hydrogen supply and other hydrogen energy bases will certainly rise, and the advantages of water electrolysis hydrogen production will be maximized.

[0004] The only energy consumed in the process of hydrogen production by water electrolysis is electricity. In order to produce more hydrogen from a certain amount of electricity, the overpotential of hydrogen evolution or oxygen evolution during electrolysis must be reduced, which depends on highly active catalysts. Noble metal catalysts are considered ideal water electrolysis materials due to their high activity, but their fatal shortcomings of high price and low reserves are not enough to support future large-scale applications.

[0005] In recent years, non-noble metal-based catalysts have attracted the attention of researchers due to their "cheap and good" characteristics. Many studies have shown that non-noble metal-based catalysts have better catalytic activity and stability than noble metal catalysts. Obviously, it is of great significance to study the structure of non-noble transition metal-based catalysts and explore the relationship between structure and catalytic performance.

[0006] In short, energy shortage and environmental problems caused by the use of traditional fossil fuels are becoming increasingly serious, and the development of clean and pollution-free new energy with abundant global reserves has become the focus of modern development. Among them, hydrogen energy has attracted close attention from all countries due to its green, efficient, clean, pollution-free and sustainable characteristics. Water electrolysis has always been a simple, safe, mature and high-purity method for hydrogen production compared to methods such as fossil fuels, photocatalysis, and biomass. It can effectively convert wind energy, solar energy, and tidal energy into chemical energy and store it in hydrogen energy. Hydrogen energy, like electricity, is a secondary energy source. Electricity is a process energy source that cannot be directly stored and needs to be stored through other means. Hydrogen itself can be directly produced, stored, and used, and it is easy to convert. Hydrogen and electricity can also complement each other, forming a perfect and efficient hydrogen-electricity complementary system. The source of hydrogen is water, and the product is also water, a clean and sustainable energy source. Using surplus electricity during the off-peak period to produce hydrogen by water electrolysis is not only beneficial for energy storage, but also can obtain high-purity product hydrogen. However, efficient catalysts are often required during water electrolysis. Noble metal-based catalysts are the most active catalysts in hydrogen evolution and oxygen evolution reactions, but their scarcity and high price limit the industrialization process of water electrolysis for hydrogen production. In recent years, researchers have made efforts and explored the development of transition metals into HER and OER catalysts with high catalytic performance, which can reduce costs and be widely used in industrial hydrogen production. We hope to prepare a full water-splitting catalyst through a simple, green, and low-cost method, increase the specific surface area of the catalyst and the active sites during electrocatalytic hydrogen evolution or oxygen evolution reactions, and improve its catalytic activity and stability, becoming a candidate material that can replace noble metal-based catalysts in the field of electrochemical full water splitting. SUMMARY

[0007] Based on the above, the application uses foamed nickel as a substrate to prepare in-situ nano-composite hydrogen evolution materials, which exhibit high efficient electrocatalytic hydrogen evolution performance, especially with ultra-high stability, and have good application prospects in the field of energy conversion.

[0008] An in-situ nano-composite hydrogen evolution material, which uses foamed nickel as a substrate and has a surface attached with a core-shell structure, wherein the core is a 30-60 nm diameter NbMn sulfide nanowire, and the shell is a 10-50 nm thickness MoMn carbide.

[0009] The composite material is used alone as a cathode, and a 10 mA / cm 2 The hydrogen evolution overpotential is 110-130 mV.

[0010] 10 mA / cm 2 At a current density, after 100 hours, the potential increases from -119.27 mV to -119.51 mV vs. RHE, only an increase of 24 mV.

[0011] The composite material is used as a cathode and an anode together for full water splitting.

[0012] An in-situ nano-composite hydrogen evolution material includes the following steps: (1) Take foamed nickel of appropriate size, and sequentially perform acid washing immersion, ethanol immersion and hot air drying treatment under the assistance of ultrasonic at 20-30℃.

[0013] (2) Prepare an electroplating solution; place the foamed nickel of step (1) as a cathode and an inert metal as an anode in the electroplating solution, and the electroplating parameters are: 8-10 A / dm 2 current density, 20-30℃ temperature, 5-15 min time, 200-300 rpm magnetic sub-stirring.

[0014] (3) Place the electroplating solution and the foamed nickel treated in step (2) in a hydrothermal reaction kettle for a first hydrothermal reaction, the first hydrothermal reaction temperature is 120-170℃, and the duration is 2-3h, and after natural cooling, take out and dry.

[0015] (4) Prepare a second hydrothermal reaction solution, place the foamed nickel obtained in step (3) in the second hydrothermal reaction solution and transfer it to a hydrothermal reaction kettle, the second hydrothermal reaction temperature is 110-120℃, and the duration is 10-12h, and after natural cooling, take out.

[0016] (5) Place the foamed nickel prepared in step (4) in a tube furnace, heat treat, naturally cool, take out, and obtain a high-stability multi-effect metal composite material.

[0017] Further, the size of the foamed nickel is 2-3 cm*2-3 cm; the pickling soaking is 4-5 wt.% HCl aqueous solution, and the time is 4-5 min; the ethanol soaking is 50-60 vol.% ethanol aqueous solution, and the soaking time is 10-15 min; and the temperature of the hot air blowing is 35-40 DEG C.

[0018] Further, the electroplating solution is composed of 0.3-0.4 mol / L manganese sulfate, 0.05-0.1 mol / L ammonium niobium oxalate, 0.1-0.2 mol / L thioacetamide, 0.2-0.4 mol / L sodium sulfate, 0.2-0.4 mol / L boric acid and deionized water.

[0019] Further, the second hydrothermal reaction solution is composed of 0.1-0.15 mol / L molybdenum trioxide, 0.3-0.4 mol / L manganese sulfate, 0.2-0.3 mol / L terephthalic acid, 0.01-0.02 mol / L cetyltrimethylammonium bromide and deionized water.

[0020] Further, the heat treatment is as follows: under the condition of inert gas protection, the temperature is raised to 400-500 DEG C and is treated for 2-3 h, when the temperature is naturally cooled to 150-200 DEG C, the inert protection gas is switched to hydrogen-nitrogen mixed gas, and the roasting is continuously carried out for 1-2 h.

[0021] Beneficial technical effects: (1) The composite material can be directly used as a cathode for hydrogen production, has excellent overall water splitting catalytic activity and stability, the high catalytic activity may be attributed to the high specific surface area or high exposed catalytic sites of the composite material, especially the nanowire core-shell structure on the surface of the foamed nickel, and the stability is closely related to the modification and doping of niobium and molybdenum, and the obtained nanometer overall water splitting composite material can realize the industrial application in the field of electrolytic water.

[0022] (2) The composite material is in-situ grown on the foamed nickel, does not need an adhesive, has strong electronic conductivity, and the heterogeneous interface and crystalline / amorphous interface between C-MoMn@S-NbMn further optimize the electronic transmission channel and improve the migration rate of electrons. BRIEF DESCRIPTION OF DRAWINGS

[0023] ATTACHMENT Figure 1 SEM diagram of the foamed nickel after pretreatment.

[0024] ATTACHMENT Figure 2 SEM diagram of the foamed nickel obtained after one hydrothermal treatment of the foamed nickel.

[0025] ATTACHMENT Figure 3 SEM diagram of the foamed nickel obtained after heat treatment of the foamed nickel.

[0026] ATTACHMENT Figure 4SEM images of (a) NbMn nanowires / foam nickel and (b) carbonized MoMn@ sulfided NbMn nanowires / foam nickel prepared by the present application.

[0027] Figure 1 Figure 5 TEM images of (a) NbMn nanowires / foam nickel and (b) carbonized MoMn@ sulfided NbMn nanowires / foam nickel prepared by the present application.

[0028] Figure 2 Figure 6 LSV curves of HER in 1.0M KOH for the examples and comparative examples of the present application.

[0029] Figure 3 Figure 7 Tafel plots of HER in 1.0M KOH for the examples and comparative examples of the present application.

[0030] Figure 4 Figure 8 Cdl plots of HER in 1.0M KOH for the examples and comparative examples of the present application.

[0031] Figure 5 Figure 9 EIS curves of HER in 1.0M KOH for the examples and comparative examples of the present application.

[0032] Figure 6 Figure 10 HER stability test for the examples of the present application. DETAILED DESCRIPTION Example 1

[0033] An in-situ nanocomposite hydrogen evolution material is prepared by the following steps comprising the following steps: (1) Take a foam nickel of appropriate size, and sequentially perform acid washing immersion, ethanol immersion and hot air drying treatment under the assistance of ultrasonic at 20℃.

[0034] (2) Prepare an electroplating solution composed of 0.3mol / L manganese sulfate, 0.05mol / L ammonium niobium oxalate, 0.1mol / L thioacetamide, 0.2mol / L sodium sulfate, 0.2mol / L boric acid and deionized water; place the foam nickel of step (1) as a cathode and an inert metal as an anode in the electroplating solution, and the electroplating parameters are: 8A / dm 2 current density, 20℃ temperature, 5min time, 200rpm magnetic sonication.

[0035] (3) Place the electroplating solution and the foam nickel treated in step (2) in a hydrothermal reactor for a first hydrothermal reaction, and the first hydrothermal reaction temperature is 120℃, and the duration is 2h, and after natural cooling and taking out, dry.

[0036] (4) A second hydrothermal reaction solution is prepared, which is composed of 0.1 mol / L molybdenum trioxide, 0.3 mol / L manganese sulfate, 0.2 mol / L terephthalic acid, 0.01 mol / L cetyltrimethylammonium bromide and deionized water. The foamed nickel obtained in step (3) is placed in the second hydrothermal reaction solution and transferred into a hydrothermal reaction kettle. The secondary hydrothermal reaction temperature is 110°C, and the duration is 10 hours. After natural cooling and removal, the foamed nickel is obtained.

[0037] (5) The foamed nickel obtained in step (4) is placed in a tube furnace. Under inert gas protection, the temperature is raised to 400°C and maintained for 2 hours. When the temperature is naturally cooled to 150°C, the inert protection gas is switched to a hydrogen-nitrogen mixed gas, and the calcination is continued for 1 hour. After natural cooling, the in-situ nano-composite hydrogen evolution material is obtained. Example 2

[0038] An in-situ nano-composite hydrogen evolution material is prepared by the following steps, including the following steps: (1) A foamed nickel of appropriate size is prepared. The foamed nickel is sequentially subjected to acid pickling immersion, ethanol immersion and hot air drying treatment under ultrasonic assistance at 25°C.

[0039] (2) An electroplating solution is prepared, which is composed of 0.35 mol / L manganese sulfate, 0.075 mol / L ammonium niobium oxalate, 0.15 mol / L thioacetamide, 0.3 mol / L sodium sulfate, 0.3 mol / L boric acid and deionized water. The foamed nickel of step (1) is used as the cathode, and an inert metal is used as the anode. The electroplating parameters are: 9 A / dm 2 current density, 25°C temperature, 10 min time, 250 rpm magnetic sub-stirring.

[0040] (3) The electroplating solution and the foamed nickel treated in step (2) are placed in a hydrothermal reaction kettle for a first hydrothermal reaction. The first hydrothermal reaction temperature is 145°C, and the duration is 2.5 hours. After natural cooling and removal, the foamed nickel is dried.

[0041] (4) A second hydrothermal reaction solution is prepared, which is composed of 0.125 mol / L molybdenum trioxide, 0.35 mol / L manganese sulfate, 0.25 mol / L terephthalic acid, 0.015 mol / L cetyltrimethylammonium bromide and deionized water. The foamed nickel obtained in step (3) is placed in the second hydrothermal reaction solution and transferred into a hydrothermal reaction kettle. The secondary hydrothermal reaction temperature is 115°C, and the duration is 11 hours. After natural cooling and removal, the foamed nickel is obtained.

[0042] (5) The foam nickel prepared in step (4) is placed in a tube furnace under inert gas protection, heated to 450℃ and treated for 2.5h, naturally cooled to 175℃, the inert protection gas is switched to hydrogen-nitrogen mixed gas, and the roasting is continued for 1.5h, naturally cooled, taken out, and an in-situ nano-composite hydrogen evolution material is obtained. Example 3

[0043] An in-situ nano-composite hydrogen evolution material is prepared by the following steps, including the following steps: (1) A foam nickel of appropriate size is taken, and the foam nickel is sequentially subjected to acid pickling immersion, ethanol immersion, and hot air drying treatment under the assistance of ultrasonic at 30℃.

[0044] (2) An electroplating solution is prepared, which is composed of 0.4mol / L manganese sulfate, 0.1 mol / L ammonium niobium oxalate, 0.2mol / L thioacetamide, 0.4mol / L sodium sulfate, 0.4mol / L boric acid, and deionized water; the foam nickel of step (1) is taken as the cathode and the inert metal as the anode, and is placed in the electroplating solution, and the electroplating parameters are: 10A / dm 2 current density, 30℃ temperature, 15min time, 300rpm magnetic stirring.

[0045] (3) The electroplating solution and the foam nickel treated in step (2) are placed in a hydrothermal reaction kettle for a first hydrothermal reaction, and the first hydrothermal reaction temperature is 170℃, and the duration is 3h, and after natural cooling and taking out, drying is performed.

[0046] (4) A second hydrothermal reaction solution is prepared, which is composed of 0.15mol / L molybdenum trioxide, 0.4 mol / L manganese sulfate, 0.3mol / L terephthalic acid, 0.02mol / L cetyltrimethylammonium bromide, and deionized water; the foam nickel obtained in step (3) is placed in the second hydrothermal reaction solution and transferred to a hydrothermal reaction kettle, and the second hydrothermal reaction temperature is 120℃, and the duration is 12h, and after natural cooling and taking out.

[0047] (5) The foam nickel prepared in step (4) is placed in a tube furnace under inert gas protection, heated to 500℃ and treated for 3h, naturally cooled to 200℃, the inert protection gas is switched to hydrogen-nitrogen mixed gas, and the roasting is continued for 2h, naturally cooled, taken out, and an in-situ nano-composite hydrogen evolution material is obtained.

[0048] Comparative Example 1 is a common foam nickel substrate, which is subjected to a pretreatment process consistent with Example 2.

[0049] Comparative Example 2 An in-situ nano-composite hydrogen evolution material is prepared by the following steps, including the following steps: (1) Take the appropriate size of the foam nickel, the foam nickel is sequentially subjected to acid pickling, ethanol soaking and hot air drying treatment under the assistance of ultrasonic at 25℃.

[0050] (2) Prepare the electroplating solution, the electroplating solution is composed of 0.35 mol / L manganese sulfate, 0.15 mol / L thioacetamide, 0.3 mol / L sodium sulfate, 0.3 mol / L boric acid and deionized water; the foam nickel of step (1) is taken as the cathode and the inert metal is taken as the anode, which are placed in the electroplating solution, and the electroplating parameters are: 9 A / dm 2 current density, 25℃ temperature, 10 min time, 250 rpm magnetic stirring.

[0051] (3) The electroplating solution and the foam nickel treated in step (2) are placed in a hydrothermal reaction kettle for a first hydrothermal reaction, the first hydrothermal reaction temperature is 145℃, and the duration is 2.5h, after natural cooling and taking out, drying.

[0052] (4) Prepare a second hydrothermal reaction solution, the second hydrothermal reaction solution is composed of 0.125 mol / L molybdenum trioxide, 0.35 mol / L manganese sulfate, 0.25 mol / L terephthalic acid, 0.015 mol / L cetyltrimethylammonium bromide and deionized water, and the foam nickel obtained in step (3) is placed in the second hydrothermal reaction solution and transferred to a hydrothermal reaction kettle, the second hydrothermal reaction temperature is 115℃, and the duration is 11h, after natural cooling and taking out.

[0053] (5) The foam nickel prepared in step (4) is placed in a tube furnace, under the condition of inert gas protection, heated to 450℃ for 2.5h, when naturally cooled to 175℃, the inert protection gas is switched to hydrogen-nitrogen mixed gas, and the calcination is continued for 1.5h, and then the material is naturally cooled and taken out to obtain an in-situ nano-composite hydrogen evolution material.

[0054] Comparative Example 3 An in-situ nano-composite hydrogen evolution material is prepared by the following steps comprising the following steps: (1) Take the appropriate size of the foam nickel, the foam nickel is sequentially subjected to acid pickling, ethanol soaking and hot air drying treatment under the assistance of ultrasonic at 25℃.

[0055] (2) Prepare a hydrothermal reaction solution, the hydrothermal reaction solution is composed of 0.125 mol / L molybdenum trioxide, 0.5 mol / L manganese sulfate, 0.1 mol / L ammonium niobium oxalate, 0.1 mol / L thioacetamide, 0.4 mol / L terephthalic acid, 0.015 mol / L cetyltrimethylammonium bromide and deionized water, and the foam nickel obtained in step (1) is placed in the hydrothermal reaction solution and transferred to a hydrothermal reaction kettle, the hydrothermal reaction temperature is 115℃, and the duration is 11h, after natural cooling and taking out.

[0056] (3) The nickel foam prepared in step (2) is placed in a tubular furnace, and under inert gas protection conditions, the temperature is raised to 450°C for 2.5 hours. When it is naturally cooled to 175°C, the inert protective gas is switched to a hydrogen-nitrogen mixed gas, and the calcination is continued for 1.5 hours. The material is naturally cooled and taken out to obtain an in-situ nanocomposite hydrogen evolution material.

[0057] First, the present invention takes nickel foam of appropriate size, and sequentially performs pickling, ethanol soaking and hot air drying under the assistance of ultrasound at 20-30°C. The morphology after treatment is shown in the attached figure. Figure 1 The surfaces shown in (a) and (b) are rough and clean, without impurities, which is conducive to subsequent electrochemical treatment.

[0058] Then, the cleaned nickel foam is subjected to electrochemical deposition treatment and hydrothermal reaction, wherein an electroplating solution is prepared, the electroplating solution consisting of 0.3-0.4 mol / L manganese sulfate, 0.05-0.1 mol / L ammonium niobium oxalate, 0.1-0.2 mol / L thioacetamide, 0.2-0.4 mol / L sodium sulfate, 0.2-0.4 mol / L boric acid and deionized water; the nickel foam of step (1) is used as a cathode and the inert metal is used as an anode, and is placed in the electroplating solution, and the electroplating parameters are: 8-10A / dm 2 Current density, temperature of 20-30°C, time of 5-15 minutes, magnetic stirring of 200-300 rpm; wherein the electroplating solution and the nickel foam treated in step (2) are placed in a hydrothermal reactor for a hydrothermal reaction, the temperature of the hydrothermal reaction is 120-170°C, the duration is 2-3 hours, and after natural cooling, the reaction is taken out and dried.

[0059] Manganese is the metal with the most negative potential that can be electrolytically reduced from aqueous solution, with a reduction potential of 1.42V. Electrodeposition of manganese coating is difficult, and hydrogen will be released at the cathode, so the experimental conditions must be strictly controlled. Niobium cannot be directly deposited into the cathode under aqueous conditions. Through the complexation of thioacetamide, some ammonium niobium oxalate is accumulated on the cathode surface, while sodium sulfate as an electrolyte and boric acid as a corrosion inhibitor can make manganese deposit on the surface of nickel foam. Sulfide NbMn hydroxide is obtained through subsequent hydrothermal treatment, and then dried. The sulfur comes from thioacetamide, and the morphology of the obtained product is as shown in the attached figure. Figure 2 As shown in (a) and (b) in the attached Figure 4 As shown in (a) of Figure 5 As shown in (a), the morphology structure is a nanowire, specifically a sulfide NbMn nanowire with a diameter of 30-60 nm. The structure effectively provides an extremely high specific surface area and active site settlement points, and improves the subsequent HER and OER catalytic activities. As for the reasons for the morphology, the present invention has not conducted much research and discussion.

[0060] Then, a second hydrothermal reaction solution is prepared, wherein the second hydrothermal reaction solution consists of 0.1-0.15 mol / L molybdenum trioxide, 0.3-0.4 mol / L manganese sulfate, 0.2-0.3 mol / L terephthalic acid, 0.01-0.02 mol / L hexadecyltrimethylammonium bromide and deionized water. The nickel foam obtained in step (3) is placed in the second hydrothermal reaction solution and transferred to a hydrothermal reactor. The secondary hydrothermal reaction temperature is 110-120°C, the duration is 10-12h, and the reaction is naturally cooled and taken out. That is, Mo-Mn-MOF material is prepared by hydrothermal reaction. The preparation of MOF material is well known in the prior art. Then heat treatment is carried out. The heat treatment is divided into two steps: one is inert heat treatment and the other is active heat treatment. Under the protection of inert gas, the temperature is raised to 400-500℃ for 2-3 hours and then naturally cooled to 150-200℃. The main purpose is to carbonize the MOF material. The inert protective gas is switched to hydrogen and nitrogen mixed gas (5vol.% H2 / N2) and the calcination is continued for 1-2 hours, mainly to activate the composite material. The morphology of the obtained product is shown in the attached figure. Figure 3 As shown in (a) and (b) in the attached Figure 4 As shown in (b) of Figure 5 As shown in (b), a core-shell structure is formed, with the shell being carbonized MoMn with a thickness of 10-50 nm.

[0061] See attached Figure 6 The HER activity of the catalysts was evaluated in a saturated 1 M KOH aqueous solution using a conventional three-electrode system. Graphite rod and Hg / HgO were used as counter electrode and reference electrode, respectively, and the prepared catalyst was used as working electrode. The linear sweep voltammetry (LSV) curves obtained here were not corrected for iR, and all potentials were relative to the standard hydrogen electrode.

[0062] At a current density of 10 mA cm −2 The overpotentials corresponding to Example 2 and Comparative Examples 1-3 are 119 mV, 299 mV, 186 mV, and 251 mV, respectively, indicating excellent HER activity. This may be attributed to the interaction of the C-MoMn@S-NbMn core-shell structure, i.e., the combined action of multiple elements enhances the HER catalytic performance, as well as the extremely high reaction site provided by the nanostructure. It should be noted that the curve distance does not change significantly with increasing current density, indicating that the present invention has high stability.

[0063] In order to explore the HER dynamics of the sample under alkaline conditions, the Tafel slope of the material was obtained by fitting the LSV curve, as shown in the attached figure. Figure 7As shown, the Tafel slope of Example 2 is 87.9 mV / dec, and the Tafel slope is between 40–120 mV / dec, indicating that its HER process follows the Volmer-Heyrovsky mechanism, which is much better than 294.1 mV / dec of Comparative Example 1, 124.6 mV / dec of Comparative Example 2, and 137.8 mV / dec of Comparative Example 3.

[0064] In order to further explore the excellent HER catalytic activity of C-MoMn@S-NbMn, the electrochemical double layer capacitance (Cdl) value of the material was obtained through the CV curves at different scan rates, as shown in the attached figure. Figure 8 As shown, C-MoMn@S-NbMn has the largest C dl The value is 17.52mF / cm 2 , much higher than 0.34 mF / cm in Comparative Example 1 2 , 12.31 mF / cm2 of Comparative Example 2 2 and 4.5 mF / cm2 of Comparative Example 3 2 This indicates that C-MoMn@S-NbMn has abundant HER active sites. We also studied the HER catalytic kinetics by electrochemical impedance spectroscopy (EIS). Figure 9 From the impedance curve, C-MoMn@S-NbMn exhibits a minimum charge transfer resistance (Rct) of 2.77Ω, which is much higher than 34.6Ω of Comparative Example 1, 6.03Ω of Comparative Example 2, and 20.73Ω of Comparative Example 3. This shows that C-MoMn@S-NbMn has efficient and rapid charge transfer capabilities, thereby achieving higher HER catalytic activity. One of the reasons for this efficient electron transfer is that the material is in situ grown on nickel foam, without the need for a binder, and has strong electron conductivity. In addition, the heterogeneous interface and crystalline / amorphous interface between C-MoMn@S-NbMn further optimize the electron transmission channel and increase the electron migration rate.

[0065] The most noteworthy feature of the present invention is its stability and durability. The durability of known electrocatalysts is another parameter for evaluating their catalytic performance in practical applications. Therefore, we conducted a long-term constant current chronopotentiometry (CP) measurement at a current density of 10 mA / cm. Figure 10From the v-t curves, the potential increased from -119.27 mV to -119.51 mV (vs. RHE) after 100 hours, only 24 mV increase. It showed that the catalyst had good stability, compared with the comparative example 2, the potential increased from -186.32 mV to -190.45 mV (vs. RHE), even had 4130 mV increase, showed the influence of Nb on stability.

[0066] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all these changes and modifications should be included in the protection scope of the claims of the present application.

Claims

1. An in-situ nanocomposite hydrogen evolution material, characterized in that The composite hydrogen evolution material uses nickel foam as a substrate, and has a core-shell structure attached to the surface, wherein the core is a sulfide NbMn nanowire with a diameter of 30-60nm, and the shell is a carbonized MoMn with a thickness of 10-50nm.

2. The use of an in-situ nanocomposite hydrogen evolution material according to claim 1, characterized in that The composite material is used as a single cathode, 10 mA / cm 2 The hydrogen evolution overpotential is 110-130mV.

3. The use of an in-situ nanocomposite hydrogen evolution material according to claim 1, characterized in that 10 mA / cm 2 At this current density, after 100 hours, the potential increased from –119.27 mV to –119.51 mV vs. RHE, an increase of only 24 mV.

4. The use of an in-situ nanocomposite hydrogen evolution material according to claim 1, characterized in that The cathode and anode are used together as the complete water splitting.

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