Method for preparing silver-copper composite nanoparticles with core-satellite structure

Abstract

The invention discloses a method for preparing silver-copper composite nanoparticles with a core-satellite structure. The method comprises the following steps: first preparing a silver nanoparticle aqueous dispersion and a mixed aqueous solution of copper nitrate trihydrate / polyvinyl pyrrolidone, fully mixing the two and performing a first ice-water bath treatment, rapidly injecting hydrazine hydrate and performing a second ice-water bath treatment, then cleaning, centrifuging, and vacuum drying to obtain the target product. The present invention can successfully prepare silver-copper composite nanoparticles with silver as the core and satellite-shaped copper nanoparticles distributed around the core (silver), and can regulate the density of the satellite-shaped copper coated around the core (silver) by changing the amount of copper nitrate trihydrate. The silver-copper composite nanoparticles with a core-satellite structure can be used as an effective tandem catalyst in the fields of biomedicine, photocatalysis, thermal catalysis, and electrocatalysis.

Description

Technical Field

[0001] The invention belongs to the field of materials and relates to a method for preparing silver-copper composite nanoparticles with a core-satellite structure. Background Art

[0002] Silver and copper are often used in biomedicine, photocatalysis, thermocatalysis, electrocatalysis and other fields due to their excellent electrical conductivity, thermal conductivity and catalytic properties. For example, in electrocatalytic applications, silver is often used as an excellent catalyst for the electrocatalytic reduction of carbon dioxide to carbon monoxide (Nat. Commun., 2021, 12, 660.); copper, due to its unique electronic structure, is often used as an excellent catalyst for the electrocatalytic reduction of carbon dioxide or carbon monoxide to produce high-value-added products such as alcohols and hydrocarbons (Chem, 2018, 4(8): 1809-1831.). Silver and copper are combined into silver-copper composite nanoparticles. In electrocatalytic applications, the silver in the silver-copper composite nanoparticles can first be used to electrocatalytically reduce carbon dioxide to carbon monoxide, and then the copper in the silver-copper composite nanoparticles can be used to in situ electrocatalytically reduce carbon monoxide to high-value-added products such as alcohols and hydrocarbons. This tandem catalytic strategy is expected to achieve even better electrocatalytic carbon dioxide reduction performance. Furthermore, this tandem catalytic strategy can also be applied to biomedicine, photocatalysis, thermocatalysis and other fields.

[0003] Common silver-copper composite nanoparticles are mostly core-shell structures, with either a silver core and a copper shell coating the silver core, or a copper core and a silver shell coating the copper core. However, these core-shell silver-copper composite nanoparticles often lack the ability to expose the core due to the dense shell coating, hindering the catalytic properties of the core metal and thus failing to function as effective catalysts for tandem catalysis. Summary of the Invention

[0004] In order to solve the problem in the prior art that the shell of silver-copper composite nanoparticles with a core-shell structure is too densely coated, which prevents the core from being exposed and the metal catalytic properties of the core from being exerted, the purpose of the present invention is to provide a method for preparing silver-copper composite nanoparticles with a core-satellite structure. The effective catalyst prepared by this method can be used as an effective catalyst for tandem catalysis and is applied in the fields of biomedicine, photocatalysis, thermal catalysis, electrocatalysis, etc.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing silver-copper composite nanoparticles having a core-satellite structure comprises the following steps:

[0007] Ultrasonic dispersion of silver nanoparticles in deionized water to obtain a silver nanoparticle aqueous dispersion;

[0008] dissolving copper salt and surfactant in deionized water to obtain a mixed aqueous solution;

[0009] After mixing the silver nanoparticle aqueous dispersion and the mixed aqueous solution, hydrazine hydrate is added at 2-4 DEG C and a reduction reaction is carried out to obtain silver-copper composite nanoparticles with a core-satellite structure.

[0010] Furthermore, the diameter of the silver nanoparticles is 50 to 500 nm.

[0011] Furthermore, the copper salt is copper nitrate trihydrate.

[0012] Furthermore, the surfactant is polyvinyl pyrrolidone.

[0013] Furthermore, the average molecular weight of polyvinyl pyrrolidone is 10,000 to 100,000.

[0014] Furthermore, the concentration of the silver nanoparticle aqueous dispersion is 1 to 20 mg / mL.

[0015] Furthermore, the concentration of the copper salt in the mixed aqueous solution is 0.01 to 0.5 mg / mL, and the concentration of the surfactant in the mixed aqueous solution is 0.01 to 0.1 g / mL.

[0016] Furthermore, the volume ratio of the silver nanoparticle aqueous dispersion to the mixed aqueous solution is 1:(2-10).

[0017] Furthermore, the concentration of hydrazine hydrate is 35 wt.%, and the volume ratio of the mixed aqueous solution to hydrazine hydrate is 1 mL: (0.1-0.4) μL.

[0018] Furthermore, the reduction reaction temperature is 2-4° C., and the time is not less than 3 minutes.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention first separately prepares an aqueous dispersion of silver nanoparticles and an aqueous solution of a copper salt and a surfactant, mixes the two, injects hydrazine hydrate, and then conducts a reduction reaction to obtain the target product, a core-satellite structure of silver-copper composite nanoparticles. The present invention uses hydrazine hydrate, which has strong reducing properties and does not introduce other impurities, as a reducing agent to reduce the copper salt to copper nanoparticles on the surface of the silver nanoparticles (core). Under low temperature conditions of 2 to 4°C and the viscosity created by the surfactant, the diffusion of the copper nanoparticles is reduced and the copper nanoparticles adhere to the surface of the silver nanoparticles (core), thereby effectively preparing silver-copper composite nanoparticles with a silver core and copper nanoparticles distributed in a satellite pattern around the core (silver). The prepared silver-copper composite nanoparticles with a core-satellite structure effectively solve the problem of traditional core-shell structures with an overly dense shell coating that prevents the core from being exposed and the catalytic properties of the core metal being fully utilized. They can be used as excellent catalysts for tandem catalysis, leveraging the catalytic properties of the core (silver) and the surrounding copper for applications in biomedicine, photocatalysis, thermal catalysis, electrocatalysis, and other fields to achieve excellent catalytic performance.

[0021] Furthermore, the preparation method of silver-copper composite nanoparticles with a core-satellite structure provided by the present invention can effectively control the density of the satellite-shaped copper coating around the core (silver) by adjusting the amount of copper nitrate trihydrate, thereby effectively controlling the catalytic performance of the silver-copper composite nanoparticles as a tandem catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a transmission electron microscope photograph of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 1 of the present invention.

[0023] Figure 2 This is a graph showing the electrocatalytic carbon dioxide reduction performance of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 1 of the present invention as a tandem catalyst.

[0024] Figure 3 This is a transmission electron microscope photograph of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 2 of the present invention.

[0025] Figure 4 This is a graph showing the electrocatalytic carbon dioxide reduction performance of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 2 of the present invention as a tandem catalyst.

[0026] Figure 5 This is a transmission electron microscope photograph of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 3 of the present invention.

[0027] Figure 6This is a graph showing the electrocatalytic carbon dioxide reduction performance of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 3 of the present invention as a tandem catalyst. DETAILED DESCRIPTION

[0028] The present invention is further illustrated by the following examples. The present invention can be better understood according to the following examples. However, it will be readily understood by those skilled in the art that the specific material ratios, process conditions, and results described in the examples are merely illustrative of the present invention and should not, and do not, limit the present invention as described in detail in the claims.

[0029] The method for preparing silver-copper composite nanoparticles having a core-satellite structure of the present invention specifically comprises the following steps:

[0030] S1. Ultrasonic dispersion of silver nanoparticles with a diameter of about 50 to 500 nm in deionized water to prepare a silver nanoparticle aqueous dispersion with a concentration of 1 to 20 mg / mL;

[0031] S2. Dissolve copper nitrate trihydrate and polyvinyl pyrrolidone (average molecular weight 10,000-100,000) in deionized water to prepare a mixed aqueous solution, wherein the concentration of copper nitrate trihydrate is 0.01-0.5 mg / mL and the concentration of polyvinyl pyrrolidone is 0.01-0.1 g / mL;

[0032] S3, fully mixing A mL of the silver nanoparticle aqueous dispersion prepared in step S1 and B mL of the mixed aqueous solution prepared in step S2, and performing a first ice-water cooling treatment at a temperature of 2-4° C. for a time of not less than 3 minutes, wherein A:B=1:(2-10);

[0033] S4. Rapidly inject C μL of 35 wt.% hydrazine hydrate into the solution obtained from the first ice-water bath treatment in step S3 at a temperature of 2 to 4° C. to carry out a reduction reaction for no less than 3 minutes, wherein B:C = 1:(0.1 to 0.4);

[0034] S5. The solution obtained by the second ice-water bath treatment in step S4 is washed with anhydrous ethanol and centrifuged at a speed of 5000 to 15000 r / min for 5 to 10 minutes. The obtained solid product is vacuum dried at 60 to 100° C. for 8 to 12 hours to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure.

[0035] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and several preferred embodiments of the present invention.

[0036] Example 1

[0037] (1) Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of approximately 200 nm in 10 mL of deionized water was prepared to prepare a silver nanoparticle aqueous dispersion with a concentration of 2.4 mg / mL;

[0038] (2) Dissolve 24.16 mg of copper nitrate trihydrate and 2 g of polyvinylpyrrolidone (average molecular weight 58,000) in 100 mL of deionized water to prepare a mixed aqueous solution;

[0039] (3) 10 mL of the silver nanoparticle aqueous dispersion prepared in step (1) and 50 mL of the mixed aqueous solution prepared in step (2) were fully mixed and subjected to a first ice-water bath treatment at a temperature of 3° C. for 5 min.

[0040] (4) Rapidly inject 10 μL of 35 wt.% hydrazine hydrate into the solution obtained from the first ice-water bath treatment in step (3), and perform a second ice-water bath treatment at a temperature of 3° C. for 5 min.

[0041] (5) The solution obtained from the second ice-water bath treatment in step (4) was washed with anhydrous ethanol and centrifuged at a speed of 8000 r / min for 10 min. The solid product was vacuum dried at 60° C. for 10 h to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure;

[0042] (6) The silver-copper composite nanoparticles with a core-satellite structure obtained in step (5) were used as a tandem catalyst to perform an electrocatalytic carbon dioxide reduction reaction test, specifically comprising the following steps: 10 mg of the silver-copper composite nanoparticles with a core-satellite structure obtained in step (5) were mixed with 30 μL of Nafion solution in 1.6 mL of isopropanol, and a mixed slurry was obtained after ultrasonic treatment for 10 min. 3 μL of the mixed slurry was dropped onto a glassy carbon electrode with a diameter of 3 mm, and the working electrode was obtained after natural drying. A sealed H-type electrolytic cell with two chambers was used, the two chambers being separated by an ion exchange membrane, the electrolyte being a potassium bicarbonate aqueous solution saturated with carbon dioxide gas at a concentration of 0.5 mol / L, the reference electrode being an Ag / AgCl electrode, the counter electrode being a platinum sheet electrode, the applied potential being -1.0 V vs. RHE, and after 30 min, the gaseous and liquid products generated in the electrolytic cell were detected by gas chromatography and liquid chromatography, and their Faraday efficiency was calculated to evaluate the selectivity of the catalyst.

[0043] Figure 1This is a transmission electron micrograph of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 1 of the present invention, showing that the core (silver) diameter of the obtained silver-copper composite nanoparticles with a core-satellite structure is approximately 200 nm, and the core (silver) is covered with relatively dense copper nanoparticles with a satellite-like distribution. The copper nanoparticles have a diameter of approximately 15 nm.

[0044] Figure 2 The electrocatalytic carbon dioxide reduction performance of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 1 of the present invention as a tandem catalyst is as follows: Figure 2 As shown, the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 1 exhibited good selectivity for reducing carbon dioxide to ethanol at a voltage of -1.0 V vs. RHE (the Faradaic efficiency of ethanol was 43%).

[0045] Example 2

[0046] (1) Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of approximately 200 nm in 10 mL of deionized water was prepared to prepare a silver nanoparticle aqueous dispersion with a concentration of 2.4 mg / mL;

[0047] (2) Dissolve 12.08 mg of copper nitrate trihydrate and 2 g of polyvinylpyrrolidone (average molecular weight 58,000) in 100 mL of deionized water to prepare a mixed aqueous solution;

[0048] (3) 10 mL of the silver nanoparticle aqueous dispersion prepared in step (1) and 50 mL of the mixed aqueous solution prepared in step (2) were fully mixed and subjected to a first ice-water bath treatment at a temperature of 3° C. for 5 min.

[0049] (4) Rapidly inject 10 μL of 35 wt.% hydrazine hydrate into the solution obtained from the first ice-water bath treatment in step (3), and perform a second ice-water bath treatment at a temperature of 3° C. for 5 min.

[0050] (5) The solution obtained from the second ice-water bath treatment in step (4) was washed with anhydrous ethanol and centrifuged at a speed of 8000 r / min for 10 min. The solid product was vacuum dried at 60° C. for 10 h to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure;

[0051] (6) The silver-copper composite nanoparticles with a core-satellite structure obtained in step (5) were used as a tandem catalyst to perform an electrocatalytic carbon dioxide reduction reaction test, specifically comprising the following steps: 10 mg of the silver-copper composite nanoparticles with a core-satellite structure obtained in step (5) were mixed with 30 μL of Nafion solution in 1.6 mL of isopropanol, and a mixed slurry was obtained after ultrasonic treatment for 10 min. 3 μL of the mixed slurry was dropped onto a glassy carbon electrode with a diameter of 3 mm, and the working electrode was obtained after natural drying. A sealed H-type electrolytic cell with two chambers was used, the two chambers being separated by an ion exchange membrane, the electrolyte being a potassium bicarbonate aqueous solution saturated with carbon dioxide gas at a concentration of 0.5 mol / L, the reference electrode being an Ag / AgCl electrode, the counter electrode being a platinum sheet electrode, the applied potential being -1.0 V vs. RHE, and after 30 min, the gaseous and liquid products generated in the electrolytic cell were detected by gas chromatography and liquid chromatography, and their Faraday efficiency was calculated to evaluate the selectivity of the catalyst.

[0052] Figure 3 This is a transmission electron micrograph of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 2 of the present invention, showing that the core (silver) diameter of the obtained silver-copper composite nanoparticles with a core-satellite structure is approximately 200 nm, and the core (silver) is covered with relatively sparse copper nanoparticles with a satellite-like distribution, and the copper nanoparticles have a diameter of approximately 10 nm.

[0053] Figure 4 The electrocatalytic carbon dioxide reduction performance of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 2 of the present invention as a tandem catalyst is as follows: Figure 4 As shown, the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 2 exhibited excellent selectivity for reducing carbon dioxide to ethanol at a voltage of -1.0 V vs. RHE (the Faradaic efficiency of ethanol was 62%).

[0054] Example 3

[0055] (1) Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of approximately 200 nm in 10 mL of deionized water was prepared to prepare a silver nanoparticle aqueous dispersion with a concentration of 2.4 mg / mL;

[0056] (2) Dissolve 4.83 mg of copper nitrate trihydrate and 2 g of polyvinylpyrrolidone (average molecular weight 58,000) in 100 mL of deionized water to prepare a mixed aqueous solution;

[0057] (3) 10 mL of the silver nanoparticle aqueous dispersion prepared in step (1) and 50 mL of the mixed aqueous solution prepared in step (2) were fully mixed and subjected to a first ice-water bath treatment at a temperature of 3° C. for 5 min.

[0058] (4) Rapidly inject 10 μL of 35 wt.% hydrazine hydrate into the solution obtained from the first ice-water bath treatment in step (3), and perform a second ice-water bath treatment at a temperature of 3° C. for 5 min.

[0059] (5) The solution obtained from the second ice-water bath treatment in step (4) was washed with anhydrous ethanol and centrifuged at a speed of 8000 r / min for 10 min. The solid product was vacuum dried at 60° C. for 10 h to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure;

[0060] (6) The silver-copper composite nanoparticles with a core-satellite structure obtained in step (5) were used as a tandem catalyst to perform an electrocatalytic carbon dioxide reduction reaction test, specifically comprising the following steps: 10 mg of the silver-copper composite nanoparticles with a core-satellite structure obtained in step (5) were mixed with 30 μL of Nafion solution in 1.6 mL of isopropanol, and a mixed slurry was obtained after ultrasonic treatment for 10 min. 3 μL of the mixed slurry was dropped onto a glassy carbon electrode with a diameter of 3 mm, and the working electrode was obtained after natural drying. A sealed H-type electrolytic cell with two chambers was used, the two chambers being separated by an ion exchange membrane, the electrolyte being a potassium bicarbonate aqueous solution saturated with carbon dioxide gas at a concentration of 0.5 mol / L, the reference electrode being an Ag / AgCl electrode, the counter electrode being a platinum sheet electrode, the applied potential being -1.0 V vs. RHE, and after 30 min, the gaseous and liquid products generated in the electrolytic cell were detected by gas chromatography and liquid chromatography, and their Faraday efficiency was calculated to evaluate the selectivity of the catalyst.

[0061] Figure 5 This is a transmission electron micrograph of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 3 of the present invention, showing that the core (silver) diameter of the obtained silver-copper composite nanoparticles with a core-satellite structure is approximately 200 nm, and the core (silver) is covered with extremely sparse copper nanoparticles with a satellite-like distribution, and the copper nanoparticles have a diameter of approximately 10 nm.

[0062] Figure 6 The electrocatalytic carbon dioxide reduction performance of the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 3 of the present invention as a tandem catalyst is as follows: Figure 6 As shown, the silver-copper composite nanoparticles with a core-satellite structure obtained in Example 3 exhibited good selectivity for reducing carbon dioxide to carbon monoxide and ethanol at a voltage of -1.0 V vs. RHE (the Faradaic efficiencies of carbon monoxide and ethanol were 63% and 25%, respectively).

[0063] Example 4

[0064] S1. Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of about 50 nm in deionized water to prepare a silver nanoparticle aqueous dispersion with a concentration of 1 mg / mL;

[0065] S2. Dissolve copper nitrate trihydrate and polyvinyl pyrrolidone (average molecular weight 10,000) in deionized water to prepare a mixed aqueous solution, wherein the concentration of copper nitrate trihydrate is 0.01 mg / mL and the concentration of polyvinyl pyrrolidone is 0.01 g / mL;

[0066] S3, thoroughly mixing 10 mL of the silver nanoparticle aqueous dispersion prepared in step S1 and 20 mL of the mixed aqueous solution prepared in step S2, and performing a first ice-water bath cooling treatment at a temperature of 2° C. for 5 min;

[0067] S4. Rapidly inject 2 μL of 35 wt.% hydrazine hydrate into the solution obtained by the first ice-water bath treatment in step S3 at 2° C. and perform a reduction reaction for 3 minutes.

[0068] S5. The solution obtained by the second ice-water bath treatment in step S4 was washed with anhydrous ethanol and centrifuged at a speed of 5000 r / min for 10 min. The obtained solid product was vacuum dried at 80° C. for 9 h to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure.

[0069] Example 5

[0070] S1. Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of about 200 nm in deionized water to prepare a silver nanoparticle aqueous dispersion with a concentration of 10 mg / mL;

[0071] S2. Dissolve copper nitrate trihydrate and polyvinyl pyrrolidone (average molecular weight 100,000) in deionized water to prepare a mixed aqueous solution, wherein the concentration of copper nitrate trihydrate is 0.05 mg / mL and the concentration of polyvinyl pyrrolidone is 0.07 g / mL;

[0072] S3, thoroughly mixing 10 mL of the silver nanoparticle aqueous dispersion prepared in step S1 and 60 mL of the mixed aqueous solution prepared in step S2, and performing a first ice-water bath cooling treatment at a temperature of 4° C. for 3 min;

[0073] S4. Rapidly inject 24 μL of 35 wt.% hydrazine hydrate into the solution obtained by the first ice-water bath treatment in step S3 at 4° C. and perform a reduction reaction for 4 minutes.

[0074] S5. The solution obtained by the second ice-water bath treatment in step S4 was washed with anhydrous ethanol and centrifuged at a speed of 15,000 r / min for 5 min. The obtained solid product was vacuum dried at 70° C. for 10 h to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure.

[0075] Example 6

[0076] S1. Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of about 300 nm in deionized water to prepare a silver nanoparticle aqueous dispersion with a concentration of 5 mg / mL;

[0077] S2. Dissolve copper nitrate trihydrate and polyvinyl pyrrolidone (average molecular weight 24,000) in deionized water to prepare a mixed aqueous solution, wherein the concentration of copper nitrate trihydrate is 0.5 mg / mL and the concentration of polyvinyl pyrrolidone is 0.03 g / mL;

[0078] S3, fully mixing 5 mL of the silver nanoparticle aqueous dispersion prepared in step S1 and 50 mL of the mixed aqueous solution prepared in step S2, and performing a first ice-water bath cooling treatment at a temperature of 3° C. for 6 min;

[0079] S4. Rapidly inject 10 μL of 35 wt.% hydrazine hydrate into the solution obtained by the first ice-water bath treatment in step S3 at 3° C. and perform a reduction reaction for 3 minutes.

[0080] S5. The solution obtained by the second ice-water bath treatment in step S4 was washed with anhydrous ethanol and centrifuged at a speed of 10,000 r / min for 7 minutes. The obtained solid product was vacuum dried at 100° C. for 8 hours to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure.

[0081] Example 7

[0082] S1. Ultrasonic dispersion of 24 mg of silver nanoparticles with a diameter of about 500 nm in deionized water to prepare a silver nanoparticle aqueous dispersion with a concentration of 20 mg / mL;

[0083] S2. Dissolve copper nitrate trihydrate and polyvinyl pyrrolidone (average molecular weight 83,000) in deionized water to prepare a mixed aqueous solution, wherein the concentration of copper nitrate trihydrate is 0.2 mg / mL and the concentration of polyvinyl pyrrolidone is 0.08 g / mL;

[0084] S3, fully mixing 8 mL of the silver nanoparticle aqueous dispersion prepared in step S1 and 50 mL of the mixed aqueous solution prepared in step S2, and performing a first ice-water bath cooling treatment at a temperature of 2° C. for 3 min;

[0085] S4. Rapidly inject 16 μL of 35 wt.% hydrazine hydrate into the solution obtained by the first ice-water bath treatment in step S3 at 2° C. and perform a reduction reaction for 7 minutes.

[0086] S5. The solution obtained by the second ice-water bath treatment in step S4 was washed with anhydrous ethanol and centrifuged at a speed of 8000 r / min for 8 min. The obtained solid product was vacuum dried at 60° C. for 12 h to obtain the target product, silver-copper composite nanoparticles with a core-satellite structure.

[0087] The method of the present invention successfully prepares silver-copper composite nanoparticles with a core-satellite structure. It can effectively prepare silver-copper composite nanoparticles with a silver core and copper nanoparticles distributed in satellite-like patterns around the core (silver). The prepared silver-copper composite nanoparticles with a core-satellite structure effectively solve the problem of traditional core-shell structures, where the shell coating is too dense, preventing the core from being exposed and the catalytic properties of the core metal from being fully utilized. These nanoparticles can be used as excellent catalysts for tandem catalysis, leveraging the catalytic properties of the core (silver) and the surrounding copper, resulting in excellent catalytic performance in fields such as biomedicine, photocatalysis, thermal catalysis, and electrocatalysis.

[0088] Furthermore, the preparation method of the silver-copper composite nanoparticles with a core-satellite structure provided by the present invention can effectively control the density of the satellite-shaped copper coated around the core (silver) by adjusting the amount of copper nitrate trihydrate. Figure 1 、 Figure 3 and Figure 5 It can be intuitively judged that Figure 1 Copper is the most concentrated in the middle. Figure 3 Second in the middle, Figure 5 Copper is the most sparse in the nanostructured silver-copper composite), thereby effectively regulating the catalytic performance of silver-copper composite nanoparticles as tandem catalysts (see Figure 2 、 Figure 4 and Figure 6 ).

[0089] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0090] It should be noted that the above description and preferred embodiments are not to be construed as limiting the design concept of the present invention. Those skilled in the art may improve and modify the technical concept of the present invention in various forms, and such improvements and modifications should be understood to fall within the scope of protection of the present invention.

Claims

1. A method for preparing silver-copper composite nanoparticles having a core-satellite structure, characterized in that: The following steps are involved: Ultrasonic dispersion of silver nanoparticles in deionized water to obtain a silver nanoparticle aqueous dispersion; Dissolving a copper salt and a surfactant in deionized water to obtain a mixed aqueous solution; the concentration of the copper salt in the mixed aqueous solution is 0.01 to 0.5 mg / mL, and the copper salt is copper nitrate trihydrate; the volume ratio of the silver nanoparticle aqueous dispersion to the mixed aqueous solution is 1:(2 to 10), and the concentration of the silver nanoparticle aqueous dispersion is 1 to 20 mg / mL; After mixing the silver nanoparticle aqueous dispersion and the mixed aqueous solution, hydrazine hydrate is added at 2 to 4° C., and a reduction reaction is carried out at 2 to 4° C. to obtain silver-copper composite nanoparticles with a core-satellite structure; The diameter of silver nanoparticles is 50 to 500 nm; The surfactant is polyvinyl pyrrolidone.

2. The method for preparing silver-copper composite nanoparticles having a core-satellite structure according to claim 1, characterized in that: The average molecular weight of polyvinylpyrrolidone is 10,000 to 100,000.

3. The method for preparing silver-copper composite nanoparticles having a core-satellite structure according to claim 1, characterized in that: The concentration of the surfactant in the mixed aqueous solution is 0.01 to 0.1 g / mL.

4. The method for preparing silver-copper composite nanoparticles having a core-satellite structure according to claim 1, wherein: The concentration of hydrazine hydrate is 35 wt.%, and the volume ratio of the mixed aqueous solution to hydrazine hydrate is 1 mL: (0.1-0.4) μL.

5. The method for preparing silver-copper composite nanoparticles having a core-satellite structure according to claim 1, wherein: The reduction reaction time is not less than 3 minutes.

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