A gold-copper intermetallic compound superlattice array and a preparation method and application thereof

Abstract

The application discloses a kind of gold copper intermetallic compound superlattice array and its preparation method and application, first gold nanoparticles are prepared;Then add the toluene solution of oleylamine to gold nanoparticles, after mixing and oscillation, take the upper oleylamine phase and stand;Acetylacetone copper is dissolved in oleylamine solution, is added to the upper oleylamine phase and is reacted to obtain gold copper nanoparticles;Oleic acid is added to gold copper nanoparticles to form superlattice by modification, then drop into diethylene glycol solution, and obtain the gold copper intermetallic compound superlattice array by natural evaporation.The gold copper intermetallic compound of the application is synthesized by high-temperature hydrothermal method, and atomic-level long-range ordered structure is synthesized, by modifying functional molecules such as oleylamine and oleic acid, under non-covalent interaction, spontaneously arranged into long-range ordered periodic structure, with adjustable electronic band structure, carrier transport efficiency and light absorption characteristics, with wide application potential in many fields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal material preparation and application, and relates to a gold-copper intermetallic compound superlattice array and a preparation method and application thereof. Specifically, through non-covalent interaction (such as van der Waals force, electrostatic force, hydrogen bond, hydrophobic interaction, etc.), a gold-copper intermetallic compound superlattice array is prepared from atomic order to particle order through a liquid-liquid interface self-assembly method without external forced intervention. BACKGROUND

[0002] With the increasing demand for sustainable energy worldwide, new energy technologies (such as solar energy, wind energy, electric vehicles, etc.) are rapidly developing. In these application scenarios, materials often need to have higher strength, hardness, high-temperature resistance, oxidation resistance, and corrosion resistance, etc. However, traditional metal materials have certain limitations in the above aspects, and it is difficult to meet the high performance requirements of modern engineering fields for materials.

[0003] Intermetallic compounds are formed by two or more metal elements, or metal and metalloid elements, through metal bonds, ionic bonds or covalent bonds, and have excellent properties such as high melting point, high strength, good oxidation resistance and corrosion resistance, etc. Therefore, it has become a research hotspot in the field of materials science. The synthesis of this material needs to precisely control the process of “atomic arrangement order”, “composition uniformity” and “structure stability”, and the core difficulty comes from the crystal characteristics of intermetallic compounds (such as ordered structure, high melting point) and the coupling constraints of multiple factors in the synthesis process (such as diffusion resistance, side reaction, morphology control). Traditional methods require a temperature of 1000 ℃ to synthesize; if the temperature is insufficient, “local unmelted area” is easy to appear, resulting in products containing pure metal impurities.

[0004] In summary, the existing technology has many problems in the preparation of intermetallic compounds, such as size unevenness caused by high-temperature synthesis, operation complexity and structure damage caused by external forced intervention, etc. These problems limit the application and development of intermetallic compounds in many fields such as catalysis, optics, sensing, etc. Therefore, developing a preparation method of intermetallic compounds that can realize atomic-level precise control and uniform size at low temperature has important scientific significance and practical value for promoting the application of metal materials in many fields. SUMMARY

[0005] The present application aims at overcoming the defects of the prior art, and provides a gold-copper intermetallic compound superlattice array and a preparation method and application thereof.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a preparation method of a gold-copper intermetallic compound superlattice array, comprising the following steps:

[0008] Mixing chloroauric acid and sodium citrate to react to obtain gold nanoparticles;

[0009] Adding a toluene solution of oleylamine to the gold nanoparticles, mixing and oscillating, and then taking the upper oleylamine phase to stand; dissolving copper acetylacetonate in an oleylamine solution, and then adding the upper oleylamine phase to react, heating to 100-140 DEG C for 30-60 min, and then heating to 250-350 DEG C for 100-150 min, and then cooling to room temperature to obtain gold-copper nanoparticles;

[0010] Adding oleic acid to the gold-copper nanoparticles to form a superlattice, and then adding a diethylene glycol solution dropwise to obtain the gold-copper intermetallic compound superlattice array through natural evaporation.

[0011] Preferably, the particle size of the gold nanoparticles is 15.12+0.73 nm.

[0012] Preferably, the reaction temperature of the mixing reaction of chloroauric acid and sodium citrate is 100-140 DEG C, and the reaction time is 15-45 min.

[0013] Preferably, the concentration of oleylamine is 10-15 mmol / L, and more preferably 10 mmol / L.

[0014] Preferably, the molar ratio of gold nanoparticles to copper acetylacetonate is 1:1-2, and more preferably 1:1.

[0015] Preferably, the concentration of oleic acid is 2.5-5.5 mmol / L.

[0016] In a second aspect, the present application provides a gold-copper intermetallic compound superlattice array prepared by the above method.

[0017] In a third aspect, the present application provides the use of the above gold-copper intermetallic compound superlattice array in photoelectrocatalysis.

[0018] Compared with the prior art, the present application has at least the following beneficial effects:

[0019] The present application proposes a low-temperature wet chemical method for synthesizing intermetallic compounds. Through non-covalent interactions, the method realizes long-range ordered periodic structures from atomic order to particle order through a liquid-liquid interface self-assembly method without external forced intervention. The atomic ordered crystal structure can reduce the probability of electron scattering, enabling more efficient transport of charge carriers in the material, thereby improving the electrical conductivity and mobility of the material. Particle ordered arrangement can further regulate the optical properties of the material, such as precise regulation of light scattering, absorption, and emission by ordered nanoparticles, for the preparation of high-performance optical devices such as photonic crystals, optical sensors, etc. Particle ordered arrangement can also optimize the electronic coupling between particles, further improving the efficiency of electron transport, which is very important for improving the operating speed and reducing the power consumption of electronic devices. For example, in high-speed integrated circuits, ordered nanoparticles can achieve faster signal transmission and processing; therefore, the adjustable electronic band structure, carrier transport efficiency, and light absorption characteristics of the gold-copper intermetallic compound superlattice array obtained by the present application can be widely adapted to the needs of catalysis, optics, sensing, and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the transmission electron microscope (TEM) image of the gold-copper intermetallic compound obtained by the present application at 200 nm.

[0021] Figure 2 is the ultraviolet absorption spectrum (UV) of the gold-copper intermetallic compound obtained by the present application.

[0022] Figure 3 is the X-Ray powder crystal diffraction (XRD) pattern of the gold-copper intermetallic compound obtained by the present application.

[0023] Figure 4 is the transmission electron microscope (TEM) image of the gold-copper intermetallic compound and superlattice array obtained by the present application at 200 nm.

[0024] Figure 5 is the superlattice array diagram of the superlattice array obtained by the present application with gold-copper intermetallic compound and superlattice array.

[0025] Figure 6 is the verification result of the photoelectrocatalytic performance of the superlattice array obtained by the present application with gold-copper intermetallic compound and superlattice array. DETAILED DESCRIPTION

[0026] As described above, in view of the fact that the synthesis of existing intermetallic compounds requires high-temperature environment and large-size defects, the present inventors have long studied and practiced and proposed the technical solution of the present application, which is mainly based on at least the following:

[0027] The AuCu intermetallic compound superlattice is prepared by using a high-temperature hydrothermal method and liquid-liquid interface assembly. The method is simple and convenient. Gold nanoparticles are synthesized in one pot, and the amount of oleylamine modification is adjusted to be transferred to the toluene phase. Acetylacetone copper is used as a copper source, and the temperature is raised to 100-140℃ for 30-60 min, and then the temperature is raised to 250-330℃ for 100-150 min to form the AuCu intermetallic compound. In this process, oleylamine acts as a reducing agent and a protective agent. Subsequently, oleic acid is introduced for modification to form a superlattice, and the oleylamine phase solution is removed and dropped into a diethylene glycol solution. After standing and evaporation for 3-4 days, a uniform AuCu superlattice is formed.

[0028] In an embodiment of the present application, the concentration of oleylamine is 10-15 mmol / L, for example, 10 mmol / L, 11 mmol / L, 12 mmol / L, 13 mmol / L, 14 mmol / L, 15 mmol / L or other values within this range can be used, and a person skilled in the art can select according to actual needs.

[0029] In an embodiment of the present application, the molar ratio of gold nanoparticles to acetylacetone copper is 1:1-2, and a person skilled in the art can select according to actual needs, which is not limited herein.

[0030] In an embodiment of the present application, the concentration of oleic acid is 2.5-5.5 mmol / L, for example, 2.5 mmol / L, 3 mmol / L, 3.5 mmol / L, 4 mmol / L, 4.5 mmol / L, 5 mmol / L, 5.5 mmol / L or other values within this range can be used, and a person skilled in the art can select according to actual needs.

[0031] It should be noted that the specific embodiments of the present application described below do not constitute a limitation on the scope of protection of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application shall be included in the scope of protection of the claims of the present application.

[0032] Example 1: Synthesis of gold nanoparticles

[0033] Add 1 mL of tetrachloroauric acid (HAuCl4) solution with a concentration of 25 mmol / L into 96 mL of deionized water, and set the temperature of the system to 110 °C; then add 1 mL of sodium citrate (SC) with a concentration of 0.5 M, and maintain the oil bath temperature at 150 °C for 50 min of continuous reaction; keep stirring until the system cools to room temperature. Take 10 mL of the above gold nanoparticle (Au NPs) solution, add 3 mL of oleylamine toluene solution with a concentration of 10 mmol / L, mix thoroughly and oscillate for 15 minutes; separate and take the upper oleylamine phase, and let it stand for 12 hours.

[0034] Example 2: Synthesis of gold copper material with atomic long-range ordered structure

[0035] Weigh 15 mg of Cu(acac)2 into a 50 ml centrifuge tube, add a certain amount of oleylamine solution, and ultrasonically dissolve it completely. Transfer it to a 50 ml three-necked flask, introduce N2, and heat it to 100 °C for 60 min. Add about 25 mg of AuNps (about 5 mg / ml), 10 ml. Heat to 140 °C for 60 min, and remove the n-hexane with a needle. Heat to 250 °C again for 150 min. After the reaction is completed, naturally cool to room temperature, and slowly add 20 ml of ethanol to precipitate the compound. Wash with ethanol for 2-3 times, and finally dry or disperse in n-hexane.

[0036] Example 3: Synthesis of gold copper superlattice material with atomic long-range ordered structure

[0037] Transfer a sufficient amount of the oleylamine phase solution of the AuCu after standing, add different concentrations of oleic acid ligand, modify for 5 days, and then drop it into a diethylene glycol solution containing 10% deionized water; place the mixed system and let it evaporate naturally for 3-4 days, and finally form a uniform ultra-thin gold copper superlattice catalyst.

[0038] Application Example 1: Application of gold-based catalyst with AuCu superlattice structure in photoelectrocatalysis

[0039] All electrochemical tests were performed on a CHI760e electrochemical workstation, the light source (PLS-FX300HU) was provided by Beijing Po Fei Technology Co., Ltd., and the test system was an H-type three-electrode electrochemical cell separated by an anion exchange membrane (Fumasep Company, model FAB-PK-130). The working electrode was an indium tin oxide (ITO) electrode with an area of 1 cm 2The counter electrode is a graphite rod, the reference electrode is a mercury / mercury oxide electrode (Hg / HgO electrode), 1 mol / L potassium hydroxide (KOH) solution is used as the internal filling liquid, and the electrolyte is 1.0 mol / L KOH solution saturated with argon (Ar). In the experiment, cyclic voltammetry activation is performed, and then LSV testing is performed, and the corresponding scanning speed is 5 mV / s.

[0040] The linear sweep voltammetry (LSV) curve result of the photoelectrocatalytic hydrogen evolution reaction is as shown in Figure 6 When the gold copper superlattice catalyst prepared by the application is used, the current density is the highest under the same potential, which indicates that the gold copper superlattice catalyst has the best electrocatalytic activity under this condition.

[0041] The above examples are not limitations of the application, and the application is not limited to the above examples only, as long as the requirements of the application are met, it belongs to the protection scope of the application.

Claims

1. A method for preparing a gold-copper intermetallic compound superlattice array, characterized in that, The preparation method includes the following steps: Chloroauric acid and sodium citrate were mixed and reacted to obtain gold nanoparticles; Add a toluene solution of oleylamine to gold nanoparticles, mix and shake, and then let the upper oleylamine phase stand. Dissolve copper acetylacetonate in the oleylamine solution, then add the upper oleylamine phase to react. Heat to 100-140 °C and react for 30-60 min, then heat to 250-350 °C again and react for 100-150 min. After the reaction is completed, cool to room temperature to obtain gold-copper nanoparticles. Oleic acid was added to gold-copper nanoparticles to modify them into a superlattice, which was then dropped into a diethylene glycol solution and naturally evaporated to obtain the gold-copper intermetallic compound superlattice array.

2. The preparation method according to claim 1, characterized in that, The gold nanoparticles have a particle size of 15.12 ± 0.73 nm.

3. The preparation method according to claim 1, characterized in that, The reaction temperature for the mixture of chloroauric acid and sodium citrate is 100-140 ℃, and the reaction time is 15-45 min.

4. The preparation method according to claim 1, characterized in that, The concentration of oleylamine is 10-15 mmol / L.

5. The preparation method according to claim 1, characterized in that, The molar ratio of gold nanoparticles to copper acetylacetone is 1:1~2.

6. The preparation method according to claim 1, characterized in that, The molar ratio of gold nanoparticles to copper acetylacetone is 1:

1.

7. The preparation method according to claim 1, characterized in that, The concentration of oleic acid is 2.5-5.5 mmol / L.

8. A gold-copper intermetallic compound superlattice array, characterized in that, It is prepared by the method described in any one of claims 1-7.

9. The application of the gold-copper intermetallic compound superlattice array as described in claim 8 in photoelectrocatalysis.

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