Transition metal doped iron selenide nano material as well as preparation and application thereof

Abstract

The invention discloses a transition metal doped iron diselenide nano material, a preparation method and application in electro-catalytic decomposition of water, a selenium source is added into a solution of an iron source and alkali, and heating reaction is performed in an inert gas environment; adding a transition metal source into the reaction system, and continuously reacting; and after the reaction is finished, collecting a solid obtained by the reaction, so as to obtain the transition metal doped iron selenide nano material. Transition metal atoms are doped into the iron selenide nano-microspheres, the conductivity of the iron selenide nano-microspheres is improved, redistribution of surface charges is induced by adjusting the Fermi level, the obtained transition metal doped iron selenide nano-material has excellent electro-catalytic hydrogen evolution and oxygen evolution performance in alkaline electrolyte, and the transition metal doped iron selenide nano-material can be applied to the field of electrocatalytic hydrogen evolution and oxygen evolution. And excellent stability is shown.

Description

Technical Field

[0001] The present invention relates to a material of a nano electrocatalyst, a preparation method thereof and an application thereof, and particularly relates to a transition metal-doped iron diselenide multi-level microsphere, a preparation method thereof and an application in electrocatalytic water splitting. Background Art

[0002] As a clean energy source with a high calorific value of combustion and no pollution of products, hydrogen energy is an ideal new energy that can replace fossil fuels. Electrocatalytic water splitting is a key energy conversion technology, which can store and generate renewable energy by decomposing water into hydrogen and oxygen. The electrocatalytic water splitting method for hydrogen production has the advantages of high hydrogen production efficiency, cost saving, high product purity, etc., and is one of the research hotspots in the current hydrogen production field. Therefore, electrocatalytic water splitting is of great significance for the production and storage of clean energy.

[0003] However, the efficiency and stability of electrocatalytic water splitting are still key challenges to be solved. Traditional electrocatalytic water splitting uses noble metals such as Pt, Ir or Ru-based metals as electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). However, the scarcity, high cost and relatively low electrochemical stability of noble metal elements limit their commercial prospects, and these catalysts still require a very high voltage (1.8 - 2.4V) to reach a high current density of 200 - 500 mA / cm 2 . Therefore, the development of efficient, stable and inexpensive electrolytic water catalysts is one of the current research hotspots.

[0004] Fe-based chalcogenides (including transition metal sulfides and selenides) have characteristics such as high conductivity and good stability, and at the same time have good HER and OER catalytic activities. Compared with sulfides, Se in selenides 2- has a larger anion size, a narrower band gap, and the 3d orbital energy level of Se is close to the 3s orbital and 3p orbital, and can participate in the bonding of Fe metal atoms. Therefore, selenides usually exhibit better metallicity and conductivity, which is beneficial to the transfer of electrons and the occurrence of catalytic reactions. In summary, iron diselenide has attracted much attention due to its rich catalytic activity and relatively rich resources, and is a candidate material expected to replace noble metals as an electrolytic water catalyst.

[0005] However, the electrocatalytic performance of iron diselenide is limited by its conductivity and surface charge distribution, so it is necessary to improve and enhance its performance to meet the requirements of practical applications. Summary of the Invention

[0006] The present application provides a transition metal-doped iron selenide nanomaterial, a preparation method thereof, and an application thereof. By doping transition metal heteroatoms into iron selenide microspheres, the conductivity thereof is improved, the surface charge is induced to redistribute, and meanwhile, its Fermi level is adjusted, thereby increasing the density and intrinsic activity of catalytic active sites and enhancing the efficiency of electrocatalytic water splitting.

[0007] The first aspect of the present application is to provide a method for preparing a transition metal-doped iron selenide nanomaterial, including:

[0008] Dissolving an iron source in an alkali,

[0009] Adding selenium to the solution of the iron source and the alkali; heating and reacting under an inert gas atmosphere;

[0010] Adding a transition metal source to the reaction system and continuing the reaction;

[0011] Collecting the solid obtained from the reaction.

[0012] In a preferred embodiment, the iron source provides Fe ions, which may be Fe 2+ and / or Fe 3+ ions. More preferably, the iron source may be one or more of iron oxides, hydroxides, inorganic acid salts, organic acid salts, and organic complexes. More preferably, the iron source may be one or several of iron oxides, hydroxides, chlorides, bromides, nitrates, sulfates, carbonates, acetates, formates, oxalates, citrates, fumarates, succinates, oleates, malates, iron amino acids, β-diketone iron complexes, β-ketoimine iron complexes, salicylic acid iron complexes, and EDTA iron complexes, such as one or more of ferric chloride, ferrous chloride, ferric nitrate, ferrous nitrate, ferric sulfate, ferrous sulfate, iron oleate, ferrous oleate, EDTA iron complex, glycine iron complex, and acetylacetone iron complex.

[0013] In a preferred embodiment, the alkali is selected from liquid organic amines or organic amine solutions. More preferably, the organic amine can dissolve the iron source and is selected from one or more of diamines and hydroxylamines. More preferably, it is selected from: ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, 2-methyl-1,3-propanediamine, ethanolamine, diethanolamine, isopropanolamine, N-butyldiethanolamine, 1-(4-hydroxyphenyl)-2-aminoethanol, 2-(2-aminoethylamino)ethanol, 2-(2-aminoethoxy)ethanol, norephedrine, 2,6-bis(2-hydroxyethylamino)toluene, N-(4-amino-2-chloro-5-nitrophenyl)ethanolamine, oleylamine, diethylenetriamine, triethylenetetramine, 1,4,7-trimethyl diethylenetriamine, erucylamine, undec-10-en-1-amine, oct-4-ene-1,8-diamine, 4,8-dodecadiene-1,12-diamine, etc.

[0014] In a preferred embodiment, the operation of dissolving the iron source in the alkali includes two steps: 1) premixing, 2) dissolving. Among them, the temperature of premixing is preferably -10 - 400 °C, more preferably 0 - 350 °C, more preferably 10 - 300 °C, more preferably 20 - 250 °C, more preferably 50 - 200 °C, more preferably 100 - 150 °C.

[0015] In a preferred embodiment, the time of premixing is preferably such that the iron source can be dissolved in the alkali, for example, it can be at least 15 minutes, more preferably 30 minutes - 12 hours, more preferably 45 minutes - 10 hours, more preferably 1 - 6 hours, more preferably 3 - 5 hours.

[0016] In a preferred embodiment, the dissolving is achieved under heating conditions, and the heating temperature enables the iron source to be dissolved in the alkali.

[0017] More preferably, the heating temperature is preferably 40 - 500 °C, more preferably 50 - 450 °C, more preferably 80 - 400 °C, more preferably 100 - 380 °C, more preferably 120 - 350 °C, more preferably 150 - 300 °C, more preferably 200 - 250 °C.

[0018] In a preferred embodiment, the inert gas is preferably one or more selected from hydrogen, argon, and nitrogen.

[0019] In a preferred embodiment, the molar ratio of the iron source to the alkali is preferably 1∶(1 - 1000), more preferably 1∶(1.5 - 900), more preferably 1∶(5 - 800), more preferably 1∶(9 - 600), more preferably 1∶(10 - 400), more preferably 1∶(15 - 300), more preferably 1∶(30 - 200), more preferably 1∶(20 - 150), more preferably 1∶(50 - 100).

[0020] In a preferred embodiment, selenium is dissolved in thiol and then added to the solution of the iron source and the alkali; more preferably, selenium is dissolved in the alkali and thiol and then added to the solution of the iron source and the alkali.

[0021] In a preferred embodiment, the thiol is selected from one or more of monothiols, dithiols or polythiols (at least trithiols) having 1 to 25 carbon atoms, more preferably selected from methanethiol, ethanethiol, propanethiol, isopropanethiol, isobutanethiol, sec-butanethiol, tert-butanethiol, benzyl mercaptan, ethanedithiol, 1,3-propanedithiol, 1,5-pentanedithiol, 1,2-butanedithiol, 1,6-hexanedithiol, 3-methyl-2-butanethiol, 1,8-octanedithiol, 1,10-decanedithiol, 1-dodecanethiol, 1-methylbutanethiol, 2,3-butanedithiol, 1-pentanethiol, isopentanethiol, 1-hexanethiol, 1-octanethiol, 1-nonanethiol, 1-heptanethiol, cyclohexyl mercaptan, 2-methyl-1-butanethiol, 1-tetradecanethiol, tert-dodecanethiol, tert-nonyl mercaptan, 1-octadecanethiol, 1-hexadecanethiol, sec-octanethiol, isooctanethiol, 1,9-nonanedithiol, biphenyl-4,4'-dithiol, p-tert-butylbenzyl mercaptan, 2-methyltetrahydrofuran-3-thiol, 1-p-menthene-8-thiol, 1-methoxy-3-hexanethiol.

[0022] In a preferred embodiment, the molar ratio of selenium to the iron source is preferably 1:(0.001 - 50), more preferably 1:(0.005 - 45), more preferably 1:(0.01 - 40), more preferably 1:(0.05 - 35), more preferably 1:(0.1 - 30), more preferably 1:(0.3 - 25), more preferably 1:(0.5 - 20), more preferably 1:(1 - 15), more preferably 1:(3 - 12), more preferably 1:(5 - 10).

[0023] In a preferred embodiment, when added to the mixture of the iron source and the base, the temperature of selenium (or the temperature of the selenium and thiol solution) is preferably 10 - 200 °C, more preferably 15 - 150 °C, more preferably 20 - 120 °C, more preferably 25 - 100 °C, more preferably 30 - 80 °C, more preferably 35 - 60 °C, more preferably 40 - 50 °C.

[0024] In a preferred embodiment, the heating reaction temperature is preferably 50 - 500 °C, more preferably 80 - 450 °C, more preferably 100 - 400 °C, more preferably 120 - 350 °C, more preferably 150 - 350 °C, more preferably 200 - 300 °C.

[0025] In a preferred embodiment, the heating rate of the heating reaction temperature is preferably 0.1 - 15 °C / min, more preferably 0.5 - 10 °C / min, more preferably 1 - 8 °C / min, more preferably 3 - 5 °C / min.

[0026] In a preferred embodiment, the heating reaction time is preferably at least 3 minutes, more preferably at least 5 minutes, more preferably 8 - 90 minutes, more preferably 10 - 75 minutes, more preferably 15 - 60 minutes, and most preferably 30 - 45 minutes.

[0027] In a preferred embodiment, the transition metal source provides non - iron transition metal ions. The transition metal can be an element selected from VIB, VIIB, V, IB, and IIB in the periodic table, more preferably one or more selected from Mn, Mo, Co, Ni, Cu, and Zn, and most preferably one or more of Co, Ni, Cu, and Mo.

[0028] In a preferred embodiment, the transition metal source can be one or more of oxides, hydroxides, inorganic acid salts, organic acid salts, organic complexes, transition metal acids, and transition metal acid salts. More preferably, the transition metal source can be one or several of molybdic acid, molybdates, oxides, hydroxides, chlorides, bromides, nitrates, sulfates, carbonates, acetates, formates, oxalates, citrates, fumarates, succinates, oleates, malates, iron amino acid, β - diketone complexes, β - ketoimine complexes, salicylic acid complexes, and EDTA, such as one or more of chlorides, nitrates, sulfates, amino acid salts, EDTA complexes, glycine complexes, and acetylacetone complexes.

[0029] In a preferred embodiment, the molar ratio of the transition metal source to the iron source (calculated based on the molar ratio of the transition metal element to the iron element) is preferably 1:(0.1 - 15000), more preferably 1:(0.5 - 12000), more preferably 1:(1 - 10000), more preferably 1:(5 - 8000), more preferably 1:(10 - 6000), more preferably 1:(30 - 5000), more preferably 1:(50 - 3000), more preferably 1:(100 - 2000), more preferably 1:(200 - 1500), and most preferably 1:(500 - 1000).

[0030] In a preferred embodiment, the transition metal source is dissolved in a base and then added to the reaction system.

[0031] In a preferred embodiment, when added to the reaction system, the temperature of the transition metal source (or the alkaline solution of the transition metal source) is preferably 50 - 400 °C, more preferably 70 - 350 °C, more preferably 100 - 300 °C, and most preferably 150 - 250 °C.

[0032] In a preferred embodiment, after the transition metal source is added to the reaction system, the reaction temperature is preferably 50 - 500 °C, more preferably 80 - 450 °C, more preferably 100 - 400 °C, more preferably 120 - 350 °C, and more preferably 150 - 300 °C.

[0033] In a preferred embodiment, after the transition metal source is added to the reaction system, the reaction time is preferably at least 5 minutes, more preferably 5 - 120 minutes, more preferably 10 - 80 minutes, more preferably 15 - 60 minutes, and more preferably 30 - 45 minutes.

[0034] The second aspect of the present application is to provide a transition metal-doped iron selenide nanomaterial. Preferably, the transition metal-doped iron selenide nanomaterial is prepared by the method described in the first aspect.

[0035] The second aspect of the present application is to provide the application of the transition metal-doped iron selenide nanomaterial, especially its application as an electrocatalyst.

[0036] In a preferred embodiment, the transition metal-doped iron selenide nanomaterial is used as an electrocatalyst for electrocatalytic water splitting or an electrocatalyst for the electrode in an electrocatalytic water splitting device.

[0037] In a preferred embodiment, the electrocatalytic water splitting is alkaline tank electrolysis of water.

[0038] The present application dopes transition metal atoms into iron selenide nanospheres to improve the conductivity of the iron selenide nanospheres and induce the redistribution of surface charges by adjusting the Fermi level.

[0039] The synthesized transition metal-doped iron selenide nanomaterial of the present application has excellent electrocatalytic hydrogen evolution and oxygen evolution performances in an alkaline electrolyte. In 1 M KOH, when the current density reaches 10 mA / cm 2 ², the overpotential of the oxygen evolution reaction is only 230 - 260 mV, lower than the overpotential of undoped iron selenide (278 mV), and the potential shows no obvious attenuation within 18 hours, demonstrating excellent stability. The preparation steps of the transition metal-doped iron selenide nanomaterial of the present application are simple, and it has the characteristics of short synthesis time, uniform morphology, high flexibility, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0041] Figure 1 is the XRD spectrum of the molybdenum-doped iron selenide nanospheres of this application;

[0042] Figure 2 SEM image of iron selenide nanospheres doped with cobalt, nickel, copper, manganese and molybdenum;

[0043] Figure 3 TEM image of molybdenum-doped iron selenide nanospheres;

[0044] Figure 4 Hydrogen evolution performance curve of molybdenum-doped iron selenide nanospheres;

[0045] Figure 5 Oxygen evolution performance curve of molybdenum-doped iron selenide nanospheres. Detailed implementation manners

[0046] This application provides a transition metal-doped iron selenide nanomaterial, its preparation method and application. To make the purpose, technical solution and effect of this application clearer and more definite, the following further elaborates this application with reference to the attached drawings and by way of examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0047] It should be noted that the terms "first", "second", etc. in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0048] Example 1: Preparation of molybdenum-doped iron selenide multi-level microspheres

[0049] (1) First, add 0.5 millimoles of ferric chloride and 10 milliliters of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 hours, and then introduce nitrogen for protection.

[0050] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0051] (3) Mix 1 millimole of selenium powder, 1 milliliter of oleylamine, and 2.5 milliliters of 1-dodecanethiol, and stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor. Quickly inject this selenium precursor solution into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changes from dark red to black.

[0052] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold at 200 °C for 30 minutes.

[0053] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution and stir at 60 °C for 20 minutes to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0054] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and hold at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0055] (7) Cool the mixture to room temperature, centrifuge by adding ethanol and toluene to remove unreacted starting materials, and finally dry the sample under vacuum overnight.

[0056] Performance Detection

[0057] 1. Preparation of KOH electrolyte

[0058] Dissolve KOH in 50 mL of ultrapure water. After the KOH solution is completely dissolved and cooled, make up the volume to 100 mL in a volumetric flask to prepare 1 mol / L KOH electrolyte.

[0059] 2. Preparation of nickel foam

[0060] First, pretreat the nickel foam. Cut the nickel foam into pieces of 1 cm × 2 cm. Slowly pour 1 mL of hydrochloric acid into 10 mL of deionized water, and then immerse the cut nickel foam into the above solution, acetone, and deionized water respectively, and ultrasonicate for 30 minutes to wash away the impurities on the surface of the nickel foam. After the ultrasonic cleaning is completed, dry it overnight in a vacuum drying oven.

[0061] 3. Preparation of working electrode

[0062] First, mix 5 mg of molybdenum-doped iron selenide, 330 μL of deionized water, 110 μL of absolute ethanol, and 40 μL of Nafion, and then perform ultrasonic treatment to obtain a homogeneous mixture. Then, pipette 100 μL of the above mixture and evenly drop it on the treated nickel foam, and dry it at room temperature.

[0063] 4. Electrocatalytic application

[0064] 4.1 Activation treatment of electrocatalyst

[0065] (1) Tests were carried out using a CHI 660E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.). The working electrode was iron molybdenum-doped selenium supported on nickel foam with an area of [area value], the counter electrode was a graphite rod electrode, the reference electrode was a Hg / HgO electrode, and the electrolyte was 1 mol / L KOH electrolyte;

[0066] (2) Cyclic voltammetry (CV) activation: Before measuring the performance of the electrode to be tested, cyclic voltammetry was first used to activate the electrode. The scanning rate was 100 mV / s, and it was cycled 100 times. After the electrode reached a stable state, polarization curve tests were carried out.

[0067] 4.2 Linear sweep voltammetry (LSV) test

[0068] The scanning rate of linear sweep voltammetry was 5 mV / s (using automatic IR compensation with a 90% compensation level). All potentials were calibrated according to the reversible hydrogen electrode RHE, and the formula was: E(vs.RHE) = E(vs.Hg / HgO) + 0.098 + 0.059 × pH.

[0069] Figure 1 is the XRD pattern of molybdenum-doped iron selenide (Mo-doped FeSe2). The diffraction peaks are similar to those of FeSe2, indicating that it is a kind of Mo-doped FeSe2.

[0070] Figure 2 In the photo e, it is the SEM image of molybdenum-doped iron selenide. The results show that the molybdenum-doped iron selenide obtained in Example 1 is a "sea urchin-like" hierarchical microsphere with an average diameter of 500 nm, composed of rhombus-shaped nanorods and growing radially. Figure 3 is the TEM image of typical molybdenum-doped iron selenide, further confirming that the molybdenum-doped iron selenide has a sea urchin-like morphology

[0071] The hydrogen evolution and oxygen evolution reaction performances of the electrocatalysts in the examples of the present invention were evaluated using linear cyclic voltammetry under alkaline conditions. The experimental results are shown in Figure 4 and Figure 5 . Molybdenum-doped iron selenide showed excellent OER catalytic activity. When the current density reached 10 mA / cm 2 , its overpotential was only 248 mV, lower than that of FeSe2, indicating that after transition metal doping, the overpotential was reduced, and the "sea urchin-like" nanosphere electrocatalyst of this application has excellent OER catalytic activity. The potential did not show obvious attenuation within 18 hours.

[0072] Example 2:

[0073] (1) First, 1 mmol of ferric chloride and 15 mL of oleylamine were added to a three-necked flask at room temperature, stirred under vacuum at 150 °C for 0.5 h, and then nitrogen was introduced for protection.

[0074] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0075] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, and stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a red-brown viscous selenium precursor. Quickly inject this selenium precursor solution into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changes from dark red to black.

[0076] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold at 200 °C for 30 minutes.

[0077] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution, and stir at 60 °C for 20 minutes to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0078] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and hold at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0079] (7) Cool the mixture to room temperature, add ethanol and toluene for centrifugation to remove unreacted raw materials, and finally vacuum dry the sample overnight.

[0080] The electrochemical performance test refers to Example 1. When the current density reaches 10 mA / cm 2 , its overpotential is only 250 mV, and the potential has no obvious attenuation within 18 hours.

[0081] Example 3:

[0082] (1) First, add 2 mmol of ferric chloride and 20 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 200 °C for 0.5 hour, and then introduce argon for protection.

[0083] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0084] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, and stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a red-brown viscous selenium precursor. Quickly inject this selenium precursor solution into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changes from dark red to black.

[0085] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold at 200 °C for 30 minutes.

[0086] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution and stir at 60 °C for 20 minutes until completely dissolved. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0087] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and hold at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0088] (7) Cool the mixture to room temperature, add ethanol and toluene for centrifugation to remove unreacted raw materials, and finally vacuum-dry the sample overnight.

[0089] For the electrochemical performance test, refer to Example 1. When the current density reaches 10 mA / cm 2 its overpotential is only 245 mV, and the potential shows no obvious decay within 18 hours.

[0090] Example 4:

[0091] (1) First, add 0.5 mmol of ferric chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 hours, and then introduce nitrogen for protection.

[0092] (2) Heat the above iron-oleylamine solution to 200 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0093] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor, and quickly inject the selenium precursor solution into the iron-oleylamine solution with a syringe. The color of the solution in the three-necked flask immediately changes from dark red to black.

[0094] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold at 200 °C for 30 minutes.

[0095] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution and stir at 60 °C for 20 minutes until completely dissolved. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0096] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and hold it at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0097] (7) Cool the mixture to room temperature, centrifuge by adding ethanol and toluene to remove unreacted raw materials, and finally vacuum dry the sample overnight.

[0098] The electrochemical performance test refers to Example 1. When the current density reaches 10 mA / cm 2 at this time, its overpotential is only 253 mV, and the potential shows no obvious decay within 18 hours.

[0099] Example 5:

[0100] (1) First, add 0.5 mmol of iron(III) chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 hour, and then introduce argon for protection.

[0101] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve iron(III) chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0102] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, and stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor solution. Quickly inject this selenium precursor solution into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changes from dark red to black.

[0103] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold it at 200 °C for 30 minutes.

[0104] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution, stir at 60 °C for 20 minutes to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0105] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and hold it at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0106] (7) Cool the mixture to room temperature, centrifuge by adding ethanol and toluene to remove unreacted raw materials, and finally vacuum dry the sample overnight.

[0107] The electrochemical performance test refers to Example 1. When the current density reaches 10 mA / cm 2When the current density reaches 10 mA / cm², its overpotential is only 235 mV, and the potential shows no obvious attenuation within 18 hours.

[0108] Example 6:

[0109] (1) First, add 0.5 mmol of ferric chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 h, and then introduce argon for protection.

[0110] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0111] (3) Mix 2 mmol of selenium powder, 2 mL of oleylamine, and 5 mL of tert-dodecyl mercaptan, and stir at 60 °C for 30 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor.

[0112] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min, and quickly inject the selenium precursor solution into the iron-oleylamine solution with a syringe. The color of the solution in the three-necked flask immediately changes from dark red to black. The reaction system is maintained at 200 °C for 30 minutes.

[0113] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution, stir at 60 °C for 20 minutes to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0114] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and maintain it at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0115] (7) Cool the mixture to room temperature, centrifuge by adding ethanol and toluene to remove unreacted raw materials, and finally vacuum-dry the sample overnight.

[0116] The electrochemical performance test refers to Example 1. When the current density reaches 10 mA / cm² 2 its overpotential is only 248 mV, and the potential shows no obvious attenuation within 18 hours.

[0117] Example 7:

[0118] (1) First, add 0.5 mmol of ferric chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 h, and then introduce argon for protection.

[0119] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0120] (3) Mix 3 mmol of selenium powder, 3 mL of oleylamine, and 7.5 mL of 1-dodecanethiol, and stir at 80 °C for 40 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor.

[0121] (4) Heat the reaction solution to 300 °C at a constant heating rate of 5 °C / min, and quickly inject the selenium precursor solution into the iron-oleylamine solution with a syringe. The color of the solution in the three-necked flask immediately changes from dark red to black; maintain at 300 °C for 30 minutes.

[0122] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution, and stir at 60 °C for 20 minutes to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0123] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and maintain at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0124] (7) Cool the mixture to room temperature, add ethanol and toluene for centrifugation to remove unreacted raw materials, and finally vacuum-dry the sample overnight.

[0125] The electrochemical performance test refers to Example 1. When the current density reaches 10 mA / cm 2 , its overpotential is only 236 mV, and the potential shows no obvious attenuation within 18 hours.

[0126] Example 8:

[0127] (1) First, add 0.5 mmol of ferric chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 hour, and then introduce nitrogen protection.

[0128] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0129] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, and stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor, and quickly inject the selenium precursor solution into the iron-oleylamine solution with a syringe. The color of the solution in the three-necked flask immediately changes from dark red to black.

[0130] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold at 200 °C for 30 minutes.

[0131] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution and stir at 60 °C for 20 minutes until completely dissolved. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0132] (6) Further heat the solution to 350 °C at a constant heating rate of 5 °C / min and hold at 350 °C for 60 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0133] (7) Cool the mixture to room temperature, add ethanol and toluene for centrifugation to remove unreacted starting materials, and finally dry the sample under vacuum overnight.

[0134] The electrochemical performance test was carried out with reference to Example 1. When the current density reached 10 mA / cm 2 the overpotential was only 241 mV, and the potential did not show obvious attenuation within 18 hours.

[0135] Example 9:

[0136] (1) First, add 0.5 mmol of ferric chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 hours, and then introduce nitrogen for protection.

[0137] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0138] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor, and quickly inject the selenium precursor solution into the iron-oleylamine solution with a syringe. The color of the solution in the three-necked flask immediately changes from dark red to black.

[0139] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold at 200 °C for 30 minutes.

[0140] (5) Add 0.05 mmol of molybdenum chloride to 2 mL of oleylamine solution and stir at 60 °C for 20 minutes until completely dissolved. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0141] (6) The solution was further heated to 250 °C at a constant heating rate of 5 °C / min and held at 250 °C for 30 minutes to promote the growth and assembly of molybdenum-doped iron selenide nanostructures.

[0142] (7) The mixture was cooled to room temperature, centrifuged with ethanol added to remove unreacted starting materials, and finally the sample was dried under vacuum overnight.

[0143] The electrochemical performance test was carried out with reference to Example 1. When the current density reached 10 mA / cm 2 its overpotential was only 233 mV, and the potential did not show obvious decay within 18 hours.

[0144] Example 10: Preparation of cobalt-doped iron selenide hierarchical microspheres

[0145] (1) First, 0.5 mmol of ferric chloride and 10 mL of oleylamine were added to a three-necked flask at room temperature, stirred under vacuum at 100 °C for 0.5 h, and then purged with nitrogen for protection.

[0146] (2) The above iron-oleylamine solution was heated to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changed from golden yellow to dark red.

[0147] (3) 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol were mixed and stirred at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor solution. This selenium precursor solution was quickly injected into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changed from dark red to black.

[0148] (4) The reaction solution was heated to 200 °C at a constant heating rate of 5 °C / min and held at 200 °C for 30 minutes.

[0149] (5) 0.05 mmol of cobalt acetylacetonate was added to 2 mL of oleylamine solution and stirred at 60 °C for 20 minutes to completely dissolve it. Then, it was injected into the above three-necked flask with a syringe and reacted at 200 °C for 10 minutes.

[0150] (6) The solution was further heated to 250 °C at a constant heating rate of 5 °C / min and held at 250 °C for 30 minutes to promote the growth and assembly of cobalt-doped iron selenide nanostructures.

[0151] (7) The mixture was cooled to room temperature, centrifuged with ethanol and toluene added to remove unreacted starting materials, and finally the sample was dried under vacuum overnight.

[0152] Figure 2Photo a shows the SEM image of cobalt-doped iron selenide. The results show that the cobalt-doped iron selenide obtained in this example is a "sea urchin-like" hierarchical microsphere with an average diameter of 500 nanometers, composed of rhombic nanorods and growing radially.

[0153] For the electrochemical performance test, referring to Example 1, when the current density reaches 10 mA / cm 2 , its overpotential is only 259 mV, and the potential shows no obvious attenuation within 18 hours.

[0154] Example 12: Preparation of copper-doped iron selenide hierarchical microspheres:

[0155] (1) First, add 0.5 millimole of ferric chloride and 10 milliliters of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 hour, and then introduce nitrogen for protection.

[0156] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0157] (3) Mix 1 millimole of selenium powder, 1 milliliter of oleylamine, and 2.5 milliliters of 1-dodecanethiol, and stir at 40 °C for 20 minutes to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor solution. Then, quickly inject this selenium precursor solution into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changes from dark red to black.

[0158] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and maintain it at 200 °C for 30 minutes.

[0159] (5) Add 0.05 millimole of copper acetylacetonate to 2 milliliters of oleylamine solution and stir at 60 °C for 20 minutes to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 minutes.

[0160] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and maintain it at 250 °C for 30 minutes to promote the growth and assembly of the copper-doped iron selenide nanostructure.

[0161] (7) Cool the mixture to room temperature, centrifuge by adding ethanol and toluene to remove unreacted raw materials, and finally vacuum-dry the sample overnight.

[0162] Figure 2 Photo c shows the SEM image of copper-doped iron selenide. The results show that the copper-doped iron selenide obtained in this example is a "sea urchin-like" hierarchical microsphere with an average diameter of 500 nanometers, composed of rhombic nanorods and growing radially.

[0163] The electrochemical performance test was carried out with reference to Example 1. When the current density reached 10 mA / cm 2 the overpotential was only 262 mV, and the potential showed no obvious attenuation within 18 hours.

[0164] Example 13: Preparation of manganese-doped iron selenide multi-level microspheres:

[0165] (1) First, 0.5 mmol of ferric chloride and 10 mL of oleylamine were added to a three-necked flask at room temperature, stirred under vacuum at 100 °C for 0.5 h, and then protected by introducing nitrogen.

[0166] (2) The above iron-oleylamine solution was heated to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changed from golden yellow to dark red.

[0167] (3) 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol were mixed and stirred at 40 °C for 20 min to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor solution. This selenium precursor solution was quickly injected into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changed from dark red to black.

[0168] (4) The reaction solution was heated to 200 °C at a constant heating rate of 5 °C / min and maintained at 200 °C for 30 min.

[0169] (5) 0.05 mmol of manganese sulfate was added to 2 mL of oleylamine solution and stirred at 60 °C for 20 min to completely dissolve it. Then, it was injected into the above three-necked flask with a syringe and reacted at 200 °C for 10 min.

[0170] (6) The solution was further heated to 250 °C at a constant heating rate of 5 °C / min and maintained at 250 °C for 30 min to promote the growth and assembly of the manganese-doped iron selenide nanostructure.

[0171] (7) The mixture was cooled to room temperature, centrifuged by adding ethanol and toluene to remove unreacted raw materials, and finally the sample was vacuum dried overnight.

[0172] Figure 2 In Photo d is the SEM image of manganese-doped iron selenide. The results show that the manganese-doped iron selenide obtained in this example is "urchin-shaped" multi-level microspheres with an average diameter of 500 nm, composed of rhombus-shaped nanorods and growing radially.

[0173] The electrochemical performance test was carried out with reference to Example 1. When the current density reached 10 mA / cm 2 the overpotential was only 259 mV, and the potential showed no obvious attenuation within 18 hours.

[0174] Example 14: Preparation of nickel-doped iron selenide hierarchical microspheres:

[0175] (1) First, add 0.5 mmol of ferric chloride and 10 mL of oleylamine to a three-necked flask at room temperature, stir under vacuum at 100 °C for 0.5 h, and then introduce nitrogen protection.

[0176] (2) Heat the above iron-oleylamine solution to 140 °C at a heating rate of 5 °C / min to completely dissolve ferric chloride in oleylamine, and the solution changes from golden yellow to dark red.

[0177] (3) Mix 1 mmol of selenium powder, 1 mL of oleylamine, and 2.5 mL of 1-dodecanethiol, and stir at 40 °C for 20 min to completely dissolve the selenium powder into a reddish-brown viscous selenium precursor. Quickly inject this selenium precursor solution into the iron-oleylamine solution with a syringe, and the color of the solution in the three-necked flask immediately changes from dark red to black.

[0178] (4) Heat the reaction solution to 200 °C at a constant heating rate of 5 °C / min and hold it at 200 °C for 30 min.

[0179] (5) Add 0.05 mmol of NiCl2 to 2 mL of oleylamine solution and stir at 60 °C for 20 min to completely dissolve it. Then, inject it into the above three-necked flask with a syringe and react at 200 °C for 10 min.

[0180] (6) Further heat the solution to 250 °C at a constant heating rate of 5 °C / min and hold it at 250 °C for 30 min to promote the growth and assembly of manganese-doped iron selenide nanostructures.

[0181] (7) Cool the mixture to room temperature, add ethanol and toluene for centrifugation to remove unreacted raw materials, and finally vacuum-dry the sample overnight.

[0182] Figure 2 Photo b in the middle is the SEM image of nickel-doped iron selenide. The results show that the nickel-doped iron selenide obtained in this example is a "sea urchin-like" hierarchical microsphere with an average diameter of 500 nm, composed of rhombus-shaped nanorods and growing radially.

[0183] For the electrochemical performance test, refer to Example 1. When the current density reaches 10 mA / cm 2 the overpotential is only 243 mV, and the potential shows no obvious attenuation within 18 h.

[0184] The specific embodiments of the present application have been described in detail above, but they are only examples, and the present application is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present application are also within the scope of the present application. Therefore, equivalent transformations and modifications made without departing from the spirit and scope of the present application should all be covered within the scope of the present application.

Claims

1. A method for preparing a transition metal-doped iron selenide nanomaterial, characterized in that the steps Comprising: The iron source is dissolved in an alkali, selenium is added to the solution of the iron source and the alkali; under an inert gas atmosphere, heating reaction is carried out; a transition metal source is added to the reaction system and the reaction continues; the solid obtained from the reaction is collected.

2. The method according to claim 1, characterized in that, The iron source provides Fe ions and is selected from one or more of iron oxides, hydroxides, inorganic acid salts, organic acid salts, organic complexes, more preferably selected from one or several of iron oxides, hydroxides, chlorides, bromides, nitrates, sulfates, carbonates, acetates, formates, oxalates, citrates, fumarates, succinates, oleates, malates, iron amino acids, β-diketone iron complexes, β-ketimine iron complexes, salicylic acid iron complexes, EDTA iron complexes, for example, one or more of ferric chloride, ferrous chloride, ferric nitrate, ferrous nitrate, ferric sulfate, ferrous sulfate, iron oleate, ferrous oleate, EDTA iron complex, glycine iron complex, acetylacetone iron complex; The alkali is selected from liquid organic amines or organic amine solutions, more preferably the organic amine can dissolve the iron source and is selected from one or more of diamines and hydroxylamines, more preferably selected from: ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, 2-methyl-1,3-propanediamine, ethanolamine, diethanolamine, isopropanolamine, N-butyldiethanolamine, 1-(4-hydroxyphenyl)-2-aminoethanol, 2-(2-aminoethylamino)ethanol, 2-(2-aminoethoxy)ethanol, norpseudoephedrine, 2,6-bis(2-hydroxyethylamino)toluene, N-(4-amino-2-chloro-5-nitrophenyl)ethanolamine, oleylamine, diethylenetriamine, triethylenetetramine, 1,4,7-trimethyldiethylenetriamine, erucylamine, undec-10-en-1-amine, oct-4-ene-1,8-diamine, 4,8-dodecadiene-1,12-diamine; The transition metal source provides non-iron transition metal ions, and the transition metal is selected from the elements in VIB, VIIB, V, IB, IIB in the periodic table of elements, more preferably selected from one or more of Mn, Mo, Co, Ni, Cu, Zn, more preferably one or more of Co, Ni, Cu, Mo; the transition metal source is selected from one or more of oxides, hydroxides, inorganic acid salts, organic acid salts, organic complexes, transition metal acids, transition metal acid salts, more preferably selected from one or several of molybdic acid, molybdates, oxides, hydroxides, chlorides, bromides, nitrates, sulfates, carbonates, acetates, formates, oxalates, citrates, fumarates, succinates, oleates, malates, amino acid salts, β-diketone complexes, β-ketimine complexes, salicylic acid complexes, EDTA complexes, more preferably selected from one or more of chlorides, nitrates, sulfates, amino acid salts, EDTA complexes, glycine complexes, acetylacetone complexes; The inert gas is preferably selected from one or more of hydrogen, argon, and nitrogen.

3. The method according to claim 1, wherein The operation of dissolving the iron source in the alkali includes two steps: 1) premixing, 2) dissolving; wherein, the temperature of the premixing is preferably -10 - 400 °C, more preferably 0 - 350 °C, more preferably 10 - 300 °C, more preferably 20 - 250 °C, more preferably 50 - 200 °C, more preferably 100 - 150 °C; The time of the premixing is preferably such that the iron source can be dissolved in the alkali, for example, it can be at least 15 minutes, more preferably 30 minutes - 12 hours, more preferably 45 minutes - 10 hours, more preferably 1 - 6 hours, more preferably 3 - 5 hours; The said dissolving is achieved under heating conditions, and the heating temperature enables the iron source to be dissolved in the alkali; preferably, the heating temperature is preferably 40 - 500 °C, more preferably 50 - 450 °C, more preferably 80 - 400 °C, more preferably 100 - 380 °C, more preferably 120 - 350 °C, more preferably 150 - 300 °C, more preferably 200 - 250 °C.

4. The method according to claim 1, wherein Selenium is dissolved in the thiol and then added to the solution of the iron source and the alkali; more preferably, selenium is dissolved in the alkali and the thiol and then added to the solution of the iron source and the alkali; preferably, the thiol is selected from one or more of monothiols, dithiols or more - thio - alcohols (at least tri - thio - alcohol) with C1 - C25, more preferably selected from one or more of methanethiol, ethanethiol, 1 - propanethiol, 2 - propanethiol, 2 - methyl - 1 - propanethiol, 2 - methyl - 2 - propanethiol, benzyl mercaptan, 1,2 - ethanedithiol, 1,3 - propanedithiol, 1,5 - pentanedithiol, 1,2 - butanedithiol, 1,6 - hexanedithiol, 3 - methyl - 2 - butanethiol, 1,8 - octanedithiol, 1,10 - decanedithiol, 1 - dodecanethiol, 1 - methyl - 1 - butanethiol, 2,3 - butanedithiol, 1 - pentanethiol, 3 - methyl - 1 - butanethiol, 1 - hexanethiol, 1 - octanethiol, 1 - nonanethiol, 1 - heptanethiol, cyclohexyl mercaptan, 2 - methyl - 1 - butanethiol, 1 - tetradecanethiol, tert - dodecyl mercaptan, tert - nonyl mercaptan, 1 - octadecanethiol, 1 - hexadecanethiol, 2 - octanethiol, 3 - methyl - 1 - heptanethiol, 1,9 - nonanedithiol, 4,4'-biphenyldithiol, 4 - tert - butylbenzyl mercaptan, 2 - methyltetrahydrofuran - 3 - thiol, 1 - p - menthene - 8 - thiol, 1 - methoxy - 3 - hexanethiol.

5. The method according to claim 1, wherein The molar ratio of the iron source to the alkali is 1∶(1 - 1000), more preferably 1∶(1.5 - 900), more preferably 1∶(5 - 800), more preferably 1∶(9 - 600), more preferably 1∶(10 - 400), more preferably 1∶(15 - 300), more preferably 1∶(30 - 200), more preferably 1∶(20 - 150), more preferably 1∶(50 - 100); The molar ratio of the selenium to the iron source is 1:(0.001 - 50), more preferably 1:(0.005 - 45), more preferably 1:(0.01 - 40), more preferably 1:(0.05 - 35), more preferably 1:(0.1 - 30), more preferably 1:(0.3 - 25), more preferably 1:(0.5 - 20), more preferably 1:(1 - 15), more preferably 1:(3 - 12), more preferably 1:(5 - 10); Based on the molar ratio of the transition metal element to the iron element, the molar ratio of the transition metal source to the iron source is 1:(0.1 - 15000), more preferably 1:(0.5 - 12000), more preferably 1:(1 - 10000), more preferably 1:(5 - 8000), more preferably 1:(10 - 6000), more preferably 1:(30 - 5000), more preferably 1:(50 - 3000), more preferably 1:(100 - 2000), more preferably 1:(200 - 1500), more preferably 1:(500 - 1000).

6. The method according to claim 1, wherein The heating reaction temperature is 50 - 500 °C, more preferably 80 - 450 °C, more preferably 100 - 400 °C, more preferably 120 - 350 °C, more preferably 150 - 350 °C, more preferably 200 - 300 °C; The heating rate of the heating reaction temperature is preferably 0.1 - 15 °C / min, more preferably 0.5 - 10 °C / min, more preferably 1 - 8 °C / min, more preferably 3 - 5 °C / min; The heating reaction time is at least 3 minutes, more preferably at least 5 minutes, more preferably 8 - 90 minutes, more preferably 10 - 75 minutes, more preferably 15 - 60 minutes, more preferably 30 - 45 minutes; When added to the mixture of the iron source and the base, the temperature of the selenium is 10 - 200 °C, more preferably 15 - 150 °C, more preferably 20 - 120 °C, more preferably 25 - 100 °C, more preferably 30 - 80 °C, more preferably 35 - 60 °C, more preferably 40 - 50 °C; When added to the reaction system, the temperature of the transition metal source is 50 - 400 °C, more preferably 70 - 350 °C, more preferably 100 - 300 °C, more preferably 150 - 250 °C; After the transition metal source is added to the reaction system, the reaction temperature is 50 - 500 °C, more preferably 80 - 450 °C, more preferably 100 - 400 °C, more preferably 120 - 350 °C, more preferably 150 - 300 °C; After the transition metal source is added to the reaction system, the reaction time is preferably at least 5 minutes, more preferably 5 - 120 minutes, more preferably 10 - 80 minutes, more preferably 15 - 60 minutes, more preferably 30 - 45 minutes.

7. A transition metal - doped iron selenide nanomaterial prepared by the method according to claim 1.

8. Use of the transition metal-doped iron selenide nanomaterial according to claim 7, characterized in that, The transition metal - doped iron selenide nanomaterial as an electro - chemical catalyst.

9. The application according to claim 8, wherein The transition metal - doped iron selenide nanomaterial is used as an electro - chemical catalyst for electro - catalytic water splitting or as an electro - chemical catalyst for the electrode in an electro - catalytic water splitting device.

10. The application according to claim 8, characterized in that The electrocatalytic water splitting is alkaline bath electrolysis of water.

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