A method for preparing graphene supported high-entropy alloy by a sacrifice template method

Abstract

The application discloses a method for preparing graphene supported high-entropy alloy by a sacrifice template method, and belongs to the field of metal chemistry. In view of the problem that in the prior art, the physical and chemical property differences of different elements will limit the uniform mixing of the elements, and not only the ideal high-entropy state is difficult to obtain, but also the selection of elements is limited, in the technical scheme of the application, the characteristics of the carbon nitride surface rich in lone pair electrons are used to adsorb metal ions, and the reducing gas generated in-situ near the metal in the heating process of the carbon nitride is used to cooperatively reduce the Gibbs free energy change of the high-entropy alloy; meanwhile, in addition to the part of the carbon nitride generating the reducing gas, the remaining carbon nitride will be converted into defect-rich graphene in-situ under the catalysis of the generated metal, so that the preparation of the graphene supported high-entropy alloy can be realized at a lower temperature.

Description

Technical Field

[0001] This invention relates to a method for preparing graphene-supported high-entropy alloys using a sacrificial template method, belonging to the field of metal chemical engineering. Background Technology

[0002] High-entropy alloys are a new type of alloy composed of five or more main metals, and they hold significant promise for applications in structural mechanics under extreme conditions, energy conversion and storage, and medical devices. Achieving atomic-level precision manufacturing of high-entropy alloys is fundamental to their applications. The differences in the physicochemical properties of different elements limit their homogeneity and miscibility, making it difficult to obtain an ideal high-entropy state and severely restricting the choice of elements. Summary of the Invention

[0003] To address the problems existing in the prior art, this application provides a method for preparing graphene-supported high-entropy alloys using a sacrificial template method, which uses carbon nitride as a sacrificial template to achieve the general preparation of high-entropy alloys.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is a method for preparing graphene-supported high-entropy alloys by a sacrificial template method, comprising the following steps:

[0005] 1) Preparation of carbon nitride;

[0006] 2) Mix carbon nitride and transition metal salt materials in a certain proportion to obtain mixture one;

[0007] 3) The mixture is transferred to a calcination device and calcined at high temperature in a gas atmosphere. After calcination, it is cooled to room temperature to obtain a graphene-supported high-entropy alloy.

[0008] In the optimized method for preparing graphene-supported high-entropy alloys using the above-mentioned sacrificial template method, the transition metal salt material is one or a mixture of several transition metal nitrates, transition metal chlorides, or transition metal sulfates.

[0009] The optimized method for preparing graphene-supported high-entropy alloys using the above-mentioned sacrificial template method includes transition metal chlorides such as calcium chloride, magnesium chloride, titanium tetrachloride, vanadium pentachloride, chromium chloride, ferric chloride, ferric dichloride, cobalt chloride, nickel chloride, copper chloride, ruthenium trichloride, iridium trichloride, zirconium chloride, hafnium chloride, tantalum pentachloride, rhenium chloride, osmium chloride, lanthanum chloride, cerium chloride, praseodymium chloride, neodymium chloride, platinum chloride, palladium chloride, and silver chloride.

[0010] Transition metal nitrates include calcium nitrate, magnesium nitrate, chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zirconium nitrate, cerium nitrate, strontium nitrate, neodymium nitrate, etc.

[0011] Transition metal sulfates include magnesium sulfate, chromium sulfate, vanadium sulfate, ferric sulfate, cobalt sulfate, nickel sulfate, copper sulfate, zirconium sulfate, and cerium sulfate.

[0012] In the optimized method for preparing graphene-supported high-entropy alloys using the above-mentioned sacrificial template method, in step 2), when carbon nitride and transition metal salt materials are mixed in a certain proportion, carbon nitride and transition metal salt materials are added to deionized water in a certain proportion and subjected to ultrasonic treatment; after stirring at room temperature, the mixture is filtered and vacuum dried.

[0013] In the optimized method for preparing graphene-supported high-entropy alloys using the above-mentioned sacrificial template method, the gas atmosphere in step 3) is argon, nitrogen, hydrogen / argon mixture, hydrogen, etc.

[0014] In step 3), the reaction temperature for high-temperature calcination is 500 to 1000 degrees Celsius, and the calcination time is 1 to 5 hours.

[0015] In the optimized method for preparing graphene-supported high-entropy alloys using the above-mentioned sacrificial template method, the mass ratio of carbon nitride to transition metal salt materials is 1000:1 to 10:1.

[0016] In step 2), the ratio of carbon nitride to deionized water is 1 gram of carbon nitride added to every 5 liters of deionized water; the ultrasonic treatment time is 30 minutes to 1 hour, and the mixture is stirred at room temperature for 24 hours.

[0017] In the optimized method for preparing graphene-supported high-entropy alloys using the sacrificial template method described above, during step 3), the temperature is increased at a rate of 10 degrees Celsius per minute during high-temperature calcination.

[0018] In the optimized method for preparing graphene-supported high-entropy alloys using the above-mentioned sacrificial template method, the carbon nitride preparation method in step 1) includes pyrolysis, hydrothermal treatment, etc.

[0019] In this application, carbon nitride can be prepared by pyrolysis of urea. The specific steps are as follows: 15 grams of urea are placed in a covered crucible and then placed in a muffle furnace. The temperature is increased to 550 degrees Celsius at a heating rate of 2.3 degrees Celsius / min and held for 4 hours. After cooling to room temperature, carbon nitride can be obtained without further processing.

[0020] The beneficial effects of this application are as follows:

[0021] In this application, carbon nitride is used as a sacrificial template. The rich lone pair electrons on the carbon nitride surface are utilized to adsorb metal ions. The reducing gas generated in situ near the metal during heating by carbon nitride synergistically reduces the Gibbs free energy change of the high-entropy alloy. Simultaneously, besides partially generating reducing gas, the remaining carbon nitride is transformed in situ into defect-rich graphene under the catalytic action of the generated metal, thus enabling the preparation of graphene-supported high-entropy alloys at relatively low temperatures. Furthermore, this method utilizes the rich lone pair electrons on the carbon nitride surface to adsorb metal ions, overcoming the limitation of homogeneous miscibility between elements due to differences in their physicochemical properties, achieving a universal preparation method for high-entropy alloys. Moreover, the graphene-supported high-entropy alloy prepared in this application is suitable for various electrocatalytic applications. Attached Figure Description

[0022] Figure 1 The image shows the XRD pattern of the graphene-supported high-entropy alloy in Example 1.

[0023] Figure 2 Raman spectroscopy of the graphene-supported high-entropy alloy in Example 1;

[0024] Figure 3 A comparison of the electrocatalytic hydrogen evolution performance of high-entropy alloy / graphene and commercial benchmark 20wt% Pt / C. Detailed Implementation

[0025] This application provides a method for preparing graphene-supported high-entropy alloys using a sacrificial template method, comprising the following steps:

[0026] 1) Carbon nitride is prepared according to existing technologies; in this application, carbon nitride can be prepared by pyrolysis, hydrothermal treatment, etc. In this application, carbon nitride can be prepared by pyrolysis of urea. The specific steps are as follows: 15 grams of urea are placed in a covered crucible, and then placed in a muffle furnace. The temperature is increased to 550 degrees Celsius at a heating rate of 2.3 degrees Celsius / min, held for 4 hours, and then cooled to room temperature. No further processing is required to obtain carbon nitride.

[0027] 2) Add carbon nitride and transition metal salt materials to deionized water in proportion and sonicate for 30 minutes to 1 hour; stir at room temperature for 24 hours, filter and vacuum dry to obtain mixture one.

[0028] 3) Transfer the mixture to a calcining device and calcine it at high temperature in an atmosphere of argon, nitrogen or other gases. The high temperature calcination temperature is increased to 500-1000 degrees Celsius at a heating rate of 10 degrees / minute, and the calcination time is 1-5 hours. After calcination, the mixture is cooled to room temperature to obtain a graphene-supported high-entropy alloy.

[0029] In this application, the transition metal salt material may be one or a mixture of several transition metal nitrates, transition metal chlorides, transition metal carbonates, or transition metal sulfates.

[0030] In this application, the transition metal chloride salts may be calcium chloride, magnesium chloride, titanium tetrachloride, vanadium pentachloride, chromium chloride, ferric chloride, ferric dichloride, cobalt chloride, nickel chloride, copper chloride, ruthenium trichloride, iridium trichloride, zirconium chloride, hafnium chloride, tantalum pentachloride, rhenium chloride, osmium chloride, lanthanum chloride, cerium chloride, praseodymium chloride, neodymium chloride, platinum chloride, palladium chloride, silver chloride, etc.

[0031] Transition metal nitrates can be calcium nitrate, magnesium nitrate, chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zirconium nitrate, cerium nitrate, strontium nitrate, neodymium nitrate, etc.

[0032] Transition metal sulfates can include magnesium sulfate, chromium sulfate, vanadium sulfate, ferric sulfate, cobalt sulfate, nickel sulfate, copper sulfate, zirconium sulfate, cerium sulfate, etc.

[0033] In this application, the mass ratio of carbon nitride to transition metal salt material is 1000:1 to 10:1.

[0034] When using deionized water to dissolve carbon nitride and transition metal salt materials, the ratio of carbon nitride to deionized water is 1 gram of carbon nitride per 5 liters of deionized water.

[0035] The features of this application will be further explained below with specific implementation examples.

[0036] Example 1

[0037] In this embodiment, carbon nitride is first prepared by pyrolysis, which is a prior art and will not be described in detail here.

[0038] Add 10 mg of carbon nitride and the same molar amounts (0.05 mmol) of ferric chloride, cobalt chloride, nickel chloride, copper chloride, and ruthenium chloride to 50 mL of deionized water, sonicate for 30 minutes, stir at room temperature for 24 hours, then filter and dry in a vacuum oven.

[0039] The dried mixture was transferred to an alumina ceramic boat and placed in a tube furnace. Argon gas was introduced for 30 minutes to completely replace the gas in the tube furnace with argon gas. Then, the temperature was increased to 800 degrees Celsius at a heating rate of 10 degrees / minute and held for 1 hour to calcine the mixture. After that, it was naturally cooled to room temperature to obtain a graphene-supported high-entropy alloy.

[0040] The morphological characteristics of the graphene-supported high-entropy alloy material obtained in this embodiment

[0041] like Figure 1As shown, XRD characterization indicates that the prepared material exhibits only a single phase (PDF#40-1147) without any related peaks of other metals, indicating the formation of a high-entropy alloy.

[0042] like Figure 2 As shown, the Raman spectrum shows that there are no characteristic peaks of carbon nitride in the graphene-supported high-entropy alloy material, only characteristic peaks of defect-rich graphene, indicating that carbon nitride has been completely transformed into defect-rich graphene.

[0043] Electrochemical performance testing of the graphene-supported high-entropy alloy material obtained in this embodiment.

[0044] Formulation and performance testing of catalyst inks

[0045] (1) Weigh 2 mg of catalyst and disperse it in 300 μL of anhydrous ethanol and 40 μL of Nafion solution with a mass fraction of 5 wt%. Sonicate for 1 h to obtain a uniformly dispersed catalyst ink.

[0046] (2) Testing of the oxygen evolution performance of the catalyst

[0047] Electrochemical tests were performed on a CHI 760E electrochemical workstation (CHI Instruments, China) using a three-electrode system. A carbon rod electrode and a reversible hydrogen electrode served as the counter and reference electrodes, respectively. The working electrode was prepared by pipetting 6 μL of catalyst ink onto a 3 mm diameter glassy carbon electrode and allowing it to air dry at room temperature. At this point, the catalyst loading on the glassy carbon electrode was 0.5 mg cm⁻². During the electrocatalytic hydrogen evolution test, the linear voltammetry curve scan rate was 5 mV s⁻¹, and the data were 95% IR compensated. The electrolyte was 1 M KOH. When testing the time-potential curve of the catalyst at a constant current density of 10 mA cm⁻², the catalyst-coated glassy carbon electrode was used as the working electrode, the carbon rod as the counter electrode, and the reversible hydrogen electrode as the reference electrode.

[0048] Description of the catalyst electrochemical performance of the graphene-supported high-entropy alloy material obtained in this embodiment.

[0049] like Figure 3 As shown, at a reference current density of 10 mA cm⁻², the overpotential of the high-entropy alloy / graphene is only 9 mV, which is better than the commercial reference 20 wt% Pt / C (37 mV).

[0050] Example 2

[0051] In this embodiment, carbon nitride is first prepared by pyrolysis, which is a prior art and will not be described in detail here.

[0052] 10 mg of carbon nitride and the same molar amounts (0.05 mmol) of platinum chloride, palladium chloride, ruthenium chloride, iridium chloride, and silver chloride were added to 50 mL of deionized water. The mixture was sonicated for 30 minutes, then stirred at room temperature for 24 hours, followed by filtration and drying in a vacuum oven.

[0053] The dried mixture was transferred to an alumina ceramic boat and placed in a tube furnace. Argon gas was introduced for 30 minutes to completely replace the gas in the tube furnace with argon gas. Then, the temperature was increased to 800 degrees Celsius at a heating rate of 10 degrees / minute and held for 1 hour to calcine the mixture. After that, it was naturally cooled to room temperature to obtain a graphene-supported high-entropy alloy.

[0054] Example 3

[0055] In this embodiment, carbon nitride is first prepared by pyrolysis, which is a prior art and will not be described in detail here.

[0056] 10 mg of carbon nitride and the same molar amounts (0.05 mmol) of chromium sulfate, cobalt sulfate, nickel sulfate, zirconium sulfate, and cerium sulfate were added to 50 mL of deionized water, sonicated for 30 minutes, stirred at room temperature for 24 hours, and then filtered and dried in a vacuum oven.

[0057] The dried mixture was transferred to an alumina ceramic boat and placed in a tube furnace. Argon gas was introduced for 30 minutes to completely replace the gas in the tube furnace with argon gas. Then, the temperature was increased to 800 degrees Celsius at a heating rate of 10 degrees / minute and held for 1 hour to calcine the mixture. After that, it was naturally cooled to room temperature to obtain a graphene-supported high-entropy alloy.

[0058] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should be protected by the present invention.

Claims

1. A method for fabricating graphene supported high-entropy alloy by a sacrificial template method, characterized in that: The method comprises the following steps: 1) preparing carbon nitride; 2) mixing the carbon nitride and a transition metal salt material in a certain proportion to obtain a mixture I; 3) transferring the mixture I to a calcination device, and performing high-temperature calcination in a gas atmosphere, and obtaining graphene loaded high-entropy alloy after cooling to room temperature after calcination; The mass ratio of carbon nitride to transition metal salt material is 1000:1 to 10:1; The transition metal salt material is one or a mixture of several of transition metal nitrate, transition metal chloride, or transition metal sulfate; The transition metal chloride includes titanium tetrachloride, vanadium pentachloride, chromium chloride, iron trichloride, iron dichloride, cobalt chloride, nickel chloride, copper chloride, ruthenium trichloride, iridium trichloride, zirconium chloride, hafnium chloride, tantalum pentachloride, rhenium chloride, osmium chloride, platinum chloride, palladium chloride, silver chloride; The transition metal nitrate includes chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zirconium nitrate; The transition metal sulfate includes chromium sulfate, vanadium sulfate, iron sulfate, cobalt sulfate, nickel sulfate, copper sulfate, zirconium sulfate.

2. The method for preparing graphene loaded high-entropy alloy by the sacrificial template method according to claim 1, wherein: In step 2), when the carbon nitride and the transition metal salt material are mixed in a certain proportion, the carbon nitride and the transition metal salt material are added to deionized water in a certain proportion and are subjected to ultrasonic treatment; after stirring at room temperature, filtration and vacuum drying are performed.

3. The method for preparing graphene loaded high-entropy alloy by the sacrificial template method according to claim 1, wherein: In step 3), the gas atmosphere is argon, nitrogen, hydrogen / argon mixed gas, or hydrogen; In step 3), the reaction temperature of high-temperature calcination is 500-1000 degrees Celsius, and the calcination time is 1-5 hours.

4. The method for preparing graphene loaded high-entropy alloy by the sacrificial template method according to claim 2, wherein: In step 2), the ratio of carbon nitride to deionized water is 1 gram of carbon nitride per 5 liters of deionized water; the ultrasonic treatment time is 30 minutes to 1 hour, and the stirring time at room temperature is 24 hours.

5. The method for preparing graphene loaded high-entropy alloy by the sacrificial template method according to claim 1, wherein: In step 3), when high-temperature calcination is performed, the temperature is raised at a rate of 10 degrees per minute.

6. The method for preparing graphene loaded high-entropy alloy by the sacrificial template method according to claim 1, wherein: In step 1), the method for preparing carbon nitride includes pyrolysis and hydrothermal treatment.

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