Thin-wall micron hollow gold ball and preparation method thereof

Abstract

The invention provides a thin-wall micron hollow gold ball and a preparation method thereof, and particularly relates to the technical field of precious metal powder. The wall thickness of the thin-wall micron hollow gold ball provided by the invention is 90-110 nm, the internal hollow volume of the thin-wall micron hollow gold ball accounts for 50-90% of the volume of the whole thin-wall micron hollow gold ball, and the average particle size is 1-3 microns. The invention also provides a preparation method which comprises the following steps: mixing an aqueous solution of Arabic gum-ethyl phenyl polyethylene glycol with an aqueous solution of a gold source, mixing the obtained mixed solution with an aqueous solution of organic amine, and carrying out a complexation reaction to obtain a turbid liquid containing the gold-amine coordination compound; the pH value of the turbid liquid containing the gold-amine coordination compound is adjusted to be 1-2, a reducing agent aqueous solution is added into the solution with the adjusted pH value, a redox reaction is carried out, and the thin-wall micron hollow gold ball is obtained. According to the method, a template is not needed, and the prepared thin-wall micron hollow gold balls are smooth in surface and uniform in wall thickness.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal powders, and in particular relates to a thin-walled micron hollow gold sphere and a preparation method thereof. Background Art

[0002] Gold has the characteristics of high conductivity, high heat transfer, anti-oxidation, anti-corrosion and excellent reflectivity to electromagnetic radiation, which makes gold-based micro- and nano-materials widely used in catalysis, energy collection, photothermal therapy, biosensing, optoelectronics and high-frequency communications. Compared with solid gold particles, hollow gold spheres have the characteristics of high atomic utilization, large specific surface area and light weight.

[0003] At present, the common methods for preparing hollow gold spheres mainly include template method (self-assembly method based on template method, alloying method, electric drive method and chemical method) and template-free method. The template method is complicated, and the template removal process has the disadvantages of template residue, long time consumption and low atomic efficiency. The hollow spheres prepared by the template-free method are multi-shell hollow spheres, and the surface of the obtained hollow spheres is irregular, not smooth, and the wall thickness is uneven. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a thin-walled micrometer hollow gold sphere and a preparation method thereof. The thin-walled micrometer hollow gold sphere prepared by the present invention does not require a template, has a smooth surface, and has a uniform wall thickness.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The invention provides a thin-walled micron hollow gold ball. The wall thickness of the thin-walled micron hollow gold ball is 90-110 nm, and the internal hollow volume of the thin-walled micron hollow gold ball accounts for 50-90% of the volume of the entire thin-walled micron hollow gold ball.

[0007] Preferably, the average particle size of the thin-walled micron hollow gold spheres is 1 to 3 μm.

[0008] The present invention also provides a method for preparing the thin-walled micron hollow gold spheres described in the above technical solution, comprising the following steps:

[0009] The aqueous solution of gum arabic-ethylphenyl polyethylene glycol and the aqueous solution of gold source are mixed, and the obtained mixed solution is mixed with the aqueous solution of organic amine to generate a complex reaction, thereby obtaining a suspension containing the gold-amine coordination compound;

[0010] The pH value of the suspension containing the gold-amine coordination compound is adjusted to 1-2, and a reducing agent aqueous solution is added to the solution after the pH value is adjusted to cause an oxidation-reduction reaction to obtain the thin-walled micron hollow gold sphere;

[0011] The molar ratio of the organic amine in the organic amine aqueous solution to the gold ions in the gold source aqueous solution is 1-2:1.

[0012] Preferably, the ratio of the mass of the gum arabic to the molar amount of gold ions in the gold source aqueous solution is 2-7 g:0.01 mol;

[0013] The mass ratio of the gum arabic to the ethylphenyl polyethylene glycol is 12 to 30:1.

[0014] Preferably, the organic amine in the organic amine aqueous solution includes one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine and dodecylamine.

[0015] Preferably, the reducing agent in the reducing agent aqueous solution includes one or more of caffeic acid, catechin and ascorbic acid.

[0016] Preferably, the molar ratio of the reducing agent to the gold ions in the gold source aqueous solution is 1 to 2:1.

[0017] Preferably, the gold source in the gold source aqueous solution is chloroauric acid.

[0018] Preferably, the step of preparing the aqueous solution of gum arabic-ethylphenyl polyethylene glycol comprises: dissolving gum arabic in water, and then adding ethylphenyl polyethylene glycol and mixing.

[0019] Preferably, after the redox reaction, the process further comprises solid-liquid separation, solid washing and drying of the obtained product liquid.

[0020] The invention provides a thin-walled micrometer hollow gold ball, wherein the wall thickness of the thin-walled micrometer hollow gold ball is 90-110 nm, and the internal hollow volume of the thin-walled micrometer hollow gold ball accounts for 50-90% of the volume of the entire thin-walled micrometer hollow gold ball. The thin-walled micrometer hollow gold ball in the invention has a smooth surface, a wall thickness of 90-110 nm, and an internal hollow volume that accounts for 50-90% of the volume of the entire thin-walled micrometer hollow gold ball, and a large hollow volume.

[0021] The present invention also provides a method for preparing the above-mentioned thin-walled micron hollow gold spheres. The present invention uses gum arabic and ethylphenyl polyethylene glycol as dispersants. The gum arabic contains polysaccharides and high-molecular-weight proteins. The amino groups in the high-molecular-weight proteins serve as protective agents to adsorb gold atoms in a covalently bonded manner to prevent agglomeration between gold particles. In the redox reaction, some proteins will cause structural changes under strong acid (pH value is 1-2) and strong oxidants. However, due to the presence of polysaccharide structures that are easily soluble in water, the gum arabic will not precipitate and flocculate powders. The ethylphenyl polyethylene glycol has a low critical micelle concentration and a strong binding force with proteins, and is used to prevent hydrophobic interactions between material molecules, thereby ensuring sufficient dissolution and structural stability of the proteins. An organic amine that is easily soluble in water is used as a complexing agent. The amino groups in the organic amines react with Au. 3+Form a more stable, water-insoluble gold-amine coordination compound, reducing Au 3+ The reaction rate is reduced to promote the directional growth of gold atoms and form micrometer hollow gold spheres. The method provided by the invention is template-free, low-cost, simple to operate, and one-step chemical synthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 This is a SEM image of the thin-walled micron hollow gold sphere prepared in Example 1;

[0024] Figure 2 This is a SEM image of the cross section of a thin-walled micron hollow gold sphere prepared in Example 1;

[0025] Figure 3 XRD pattern of thin-walled micrometer hollow gold spheres prepared in Example 1;

[0026] Figure 4 This is the SEM image of the thin-walled micron hollow gold sphere prepared in Example 2;

[0027] Figure 5 This is the SEM image of the thin-walled micron hollow gold sphere prepared in Example 3;

[0028] Figure 6 This is a SEM image of thin-walled micron hollow gold spheres prepared in Example 4;

[0029] Figure 7 SEM image of thin-walled micron hollow gold spheres prepared in Comparative Example 1. DETAILED DESCRIPTION

[0030] The invention provides a thin-walled micron hollow gold ball. The wall thickness of the thin-walled micron hollow gold ball is 90-110 nm, and the internal hollow volume of the thin-walled micron hollow gold ball accounts for 50-90% of the volume of the entire thin-walled micron hollow gold ball.

[0031] In the present invention, the wall thickness of the thin-walled micron hollow gold sphere is 90-110 nm. In a specific embodiment, the wall thickness of the thin-walled micron hollow gold sphere can be 90 nm, 100 nm or 110 nm.

[0032] In the present invention, the internal hollow volume of the thin-walled micron hollow gold sphere accounts for 50-90% of the volume of the entire thin-walled micron hollow gold sphere. In a specific embodiment, the internal hollow volume of the thin-walled micron hollow gold sphere can account for 50%, 60%, 70%, 80% or 90% of the volume of the entire thin-walled micron hollow gold sphere.

[0033] In the present invention, the average particle size of the thin-walled micron hollow gold spheres is preferably 1 to 3 μm. In a specific embodiment, the average particle size of the thin-walled micron hollow gold spheres may be 1 μm, 1.5 μm, 2 μm, 2.5 μm or 3 μm.

[0034] The thin-walled micrometer hollow gold sphere obtained by the invention has a smooth surface, a large hollow volume, a uniform particle size and a wall thickness of 90 to 110 nm.

[0035] The present invention also provides a method for preparing the thin-walled micron hollow gold spheres described in the above technical solution, comprising the following steps:

[0036] The aqueous solution of gum arabic-ethylphenyl polyethylene glycol and the aqueous solution of gold source are mixed, and the obtained mixed solution is mixed with the aqueous solution of organic amine to generate a complex reaction, thereby obtaining a suspension containing the gold-amine coordination compound;

[0037] The pH value of the suspension containing the gold-amine coordination compound is adjusted to 1-2, and a reducing agent aqueous solution is added to the solution after the pH value is adjusted to cause an oxidation-reduction reaction to obtain the thin-walled micron hollow gold sphere;

[0038] The ratio of the mass of the organic amine to the molar amount of gold ions in the gold source aqueous solution is 1 to 2:1.

[0039] In the present invention, unless otherwise specified, the raw materials and equipment used are commercially available products well known in the art.

[0040] The aqueous solution of gum arabic-ethylphenyl polyethylene glycol of the present invention is mixed with the aqueous solution of gold source to obtain a mixed solution.

[0041] In the present invention, the step of preparing the aqueous solution of gum arabic-ethylphenyl polyethylene glycol preferably comprises: dissolving gum arabic in water, and then adding ethylphenyl polyethylene glycol to mix. Gum arabic is solid, and ethylphenyl polyethylene glycol and gold source aqueous solution are liquid. After adding ethylphenyl polyethylene glycol, bubbles are easy to form. It is necessary to avoid the generation of bubbles because the reducing agent drips onto the bubbles on the liquid surface, generating a black product suspended on the liquid surface. If bubbles are generated, it is necessary to eliminate the bubbles by keeping still.

[0042] In the present invention, the volume ratio of the mass of the ethylphenyl polyethylene glycol to water is preferably 0.1g:30-60mL. In a specific embodiment, the volume ratio of the mass of the ethylphenyl polyethylene glycol to water can be 0.1g:30mL, 0.1g:33mL, 0.1g:35mL, 0.1g:40mL, 0.1g:43mL, 0.1g:45mL, 0.1g:48mL, 0.1g:50mL, 0.1g:55mL or 0.1g:60mL.

[0043] In the present invention, the gold source in the gold source aqueous solution is preferably chloroauric acid. In the present invention, the preparation of the gold source aqueous solution preferably includes: dissolving the gold flakes with aqua regia, removing nitric acid and hydrochloric acid in the solution, and preparing a chloroauric acid (HAuCl4) aqueous solution with deionized water.

[0044] In the present invention, the removal of nitric acid and hydrochloric acid in the solution is preferably performed by removing nitric acid by excess hydrochloric acid, and then removing hydrochloric acid by adding deionized water and heating to evaporate. By removing nitric acid and hydrochloric acid, it is convenient to control the pH value later.

[0045] In the present invention, the molar ratio of the mass of the gum arabic to the gold ions in the gold source aqueous solution is preferably 2 to 7 g: 0.01 mol. In a specific embodiment, the molar ratio of the mass of the gum arabic to the gold ions in the gold source aqueous solution can be 2 g: 0.01 mol, 3 g: 0.01 mol, 4 g: 0.01 mol, 5 g: 0.01 mol, 6 g: 0.01 mol or 7 g: 0.01 mol. Gum arabic contains polysaccharides and high molecular weight proteins. The amino groups in the high molecular weight proteins act as protective agents to adsorb gold ions in a covalently bonded manner to prevent agglomeration between gold particles. In the redox reaction, some proteins will cause structural changes under strong acid and strong oxidant conditions, but due to the presence of a polysaccharide structure that is easily soluble in water, gum arabic will not precipitate and flocculate the powder, and the resulting structure is stable.

[0046] In the present invention, the mass ratio of gum arabic to ethylphenyl polyethylene glycol is preferably 12 to 30:1. In a specific embodiment, the mass ratio of gum arabic to ethylphenyl polyethylene glycol can be 12:1, 15:1, 18:1, 20:1, 22:1, 25:1, 28:1 or 30:1.

[0047] In the present invention, the mixing of the aqueous solution of gum arabic-ethylphenyl polyethylene glycol with the aqueous solution of the gold source preferably comprises: adding the aqueous solution of the gold source to the aqueous solution of gum arabic-ethylphenyl polyethylene glycol under stirring and stirring for 10 to 20 minutes.

[0048] In the present invention, the aqueous solution of gum arabic-ethylphenyl polyethylene glycol is used as a dispersant solution, which can disperse the gold ions evenly and prevent the subsequent gold particles from agglomerating.

[0049] After the mixed solution is obtained, the present invention mixes the mixed solution with an organic amine aqueous solution to generate a complex reaction, thereby obtaining a suspension containing a gold-amine coordination compound.

[0050] In the present invention, the organic amine in the organic amine aqueous solution preferably includes one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine and dodecylamine. In a specific embodiment, the organic amine in the organic amine aqueous solution may include ethylenediamine, propylenediamine or dodecylamine. The organic amine acts as a complexing agent, and the amino group in the organic amine reacts with Au. 3+ Form a stable, water-insoluble gold-amine coordination compound to reduce Au 3+ The reaction rate promotes the directional growth of gold atoms and the formation of micron-sized hollow gold spheres.

[0051] In the present invention, the concentration of the organic amine aqueous solution is preferably 0.5-1.5 mol / L. In a specific embodiment, the concentration of the organic amine aqueous solution is preferably 0.5 mol / L, 1 mol / L or 1.5 mol / L.

[0052] In the present invention, the molar ratio of the organic amine to the gold ions in the gold source aqueous solution is preferably 1 to 2:1. In a specific embodiment, the molar ratio of the organic amine to the gold ions in the gold source aqueous solution can be 1:1, 1.5:1 or 2:1.

[0053] In the present invention, the mixing of the mixed liquid with the organic amine aqueous solution preferably includes: adding the organic amine aqueous solution to the mixed liquid, and stirring for 25 to 35 minutes. In a specific embodiment, the stirring time can be 25 minutes, 30 minutes or 35 minutes.

[0054] In the present invention, the mixing is preferably carried out by stirring at room temperature. The present invention has no special requirements on the stirring method, and conventional technical means in the art can be used.

[0055] In the mixing process of the present invention, a complex reaction occurs, specifically, the amino group in the organic amine reacts with Au 3+ Forms a stable, water-insoluble gold-amine coordination compound.

[0056] After obtaining the suspension containing the gold-amine coordination compound, the present invention adjusts the pH value of the suspension containing the gold-amine coordination compound to 1-2, adds a reducing agent aqueous solution to the solution after the pH value is adjusted, and generates an oxidation-reduction reaction to obtain the thin-walled micron hollow gold sphere.

[0057] In the present invention, the pH value of the suspension containing the gold-amine coordination compound is adjusted to 1-2. In a specific embodiment, the pH value of the suspension containing the gold-amine coordination compound can be adjusted to 1, 1.2, 1.5, 1.8 or 2. In the present invention, the pH of the solution is preferably adjusted using a 0.1 mol / L hydrochloric acid aqueous solution or a NaOH aqueous solution. The present invention controls the pH value, can control the reduction reaction rate, and further control the particle size of the thin-walled micron hollow gold sphere.

[0058] In the present invention, it is preferred to use deionized water to rinse the liquid surface and the stirring paddle shaft of the reactor before adding the reducing agent aqueous solution. Solid gum arabic dissolves slowly, and a trace amount is not completely dissolved after stirring, and is easily adsorbed on the liquid surface and the stirring paddle. Rinsing is performed before adding the reducing agent aqueous solution to avoid the reducing agent and the gold ions in the strong oxidant HAuCl4 adsorbed on the liquid surface and the stirring paddle to react similarly to a silver mirror, forming a gold layer, which wraps the liquid surface and the stirring paddle, and reduces the yield of hollow gold balls.

[0059] In the present invention, the reducing agent in the reducing agent aqueous solution preferably includes one or more of caffeic acid, catechin and ascorbic acid. In the present invention, the concentration of the reducing agent aqueous solution is preferably 0.5 to 1.5 mol / L. In a specific embodiment, the concentration of the reducing agent aqueous solution can be 0.5 mol / L, 1 mol / L or 1.5 mol / L.

[0060] In the present invention, the molar ratio of the reducing agent to the gold ions in the gold source aqueous solution is preferably 1 to 2:1. In a specific embodiment, the molar ratio of the reducing agent to the gold ions in the gold source aqueous solution can be 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1.

[0061] In the present invention, the redox reaction is preferably carried out at room temperature with stirring.

[0062] In the present invention, it is preferred to use hydrazine hydrate to test whether the redox reaction is complete. Specifically, a small amount of the reaction solution is tested with hydrazine hydrate to test whether the reaction is complete. If the color of the reaction solution turns black or purple, continue stirring. If the color does not change, the reaction is complete and subsequent operations are performed.

[0063] In the present invention, after the redox reaction, the process preferably further comprises subjecting the obtained product liquid to solid-liquid separation, solid washing and drying to obtain the thin-walled micron hollow gold spheres.

[0064] The present invention has no special requirements on the method of solid-liquid separation, and the commonly used technical means in the art can be adopted, such as centrifugation, filtration, etc.

[0065] In the present invention, the solid is preferably washed with 50° C. deionized water for 3 to 5 times.

[0066] In the present invention, the drying temperature is preferably 100-120°C.

[0067] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with specific embodiments below. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Any modification, equivalent replacement, improvement, etc. made to the implementation methods of the present invention based on the technical essence and general principles of the present invention without creative work should be within the scope of protection of the present invention.

[0068] Example 1

[0069] Dissolve 10g of 0.05mol gold flakes with a purity of 99.99% in aqua regia, remove nitric acid and hydrochloric acid in the solution, and use deionized water to prepare 50mL of 1mol / L chloroauric acid (HAuCl4) solution. Take 25g of gum arabic and 0.9g of ethylphenyl polyethylene glycol and dissolve them in 450mL of deionized water to obtain a dispersant solution. Take 4.5g of ethylenediamine and dissolve it in 75mL of deionized water to prepare an ethylenediamine solution with a concentration of 1mol / L. Take 13.5g of caffeic acid and dissolve it in 50mL of deionized water to prepare a caffeic acid solution with a concentration of 1mol / L.

[0070] Under stirring conditions, pour the prepared chloroauric acid solution into the dispersant solution, stir for 15 minutes, add ethylenediamine solution, continue stirring for 30 minutes to obtain a suspension, adjust the pH of the suspension to 1.4 with 0.1 mol / L hydrochloric acid or NaOH aqueous solution, add caffeic acid aqueous solution, stir until the reaction is complete, take a small amount of the reaction solution and test whether the reaction is complete with hydrazine hydrate, if the color of the reaction solution turns black or purple, continue stirring, if the color does not change, the reaction is complete, stand for stratification, pour out the supernatant, wash repeatedly with 50°C deionized water for 4 times, and dry in an oven at 110°C to obtain thin-walled micron hollow gold spheres. The mass ratio of gum arabic to HAuCl4 is 2.5:1 (the mass ratio of gum arabic to the molar amount of HAuCl4 is 5g:0.01mol), the mass ratio of ethylphenyl polyethylene glycol to HAuCl4 is 0.09:1, the molar ratio of ethylenediamine to HAuCl4 is 3:2, and the molar ratio of caffeic acid to HAuCl4 is 3:2.

[0071] The morphology of the prepared thin-walled micrometer hollow gold spheres was observed by scanning electron microscopy. Figure 1 As shown in the figure, it can be seen that the prepared thin-walled micron hollow gold sphere has a smooth surface and an average particle size of 1.5 μm. The thin-walled micron hollow gold sphere was cut and the cross-sectional morphology of the thin-walled micron hollow gold sphere was observed using a scanning electron microscope, as shown in FIG. Figure 2As shown, it can be seen that the wall thickness of each prepared thin-walled micron hollow gold sphere is 100 nm, indicating that the wall thickness is uniform.

[0072] Based on the average particle size of 1.5 μm and the wall thickness of 100 nm, the volume of the thin-walled micron hollow gold sphere is calculated to be 4 / 3×π×(1.5 / 2) 3 , the volume of the hollow part = 4 / 3×π×(1.3 / 2) 3 The volume of the hollow part divided by the volume of the sphere gives an internal hollow volume that accounts for 65% of the volume of the gold sphere.

[0073] The thin-walled micrometer hollow gold spheres were characterized by X-ray diffractometer. Figure 3 As shown, it can be seen that the prepared gold balls are of high purity and free of impurities.

[0074] Example 2

[0075] Take 25g of gum arabic and 0.9g of ethylphenyl polyethylene glycol and dissolve them in 450mL of deionized water to obtain a dispersant solution. Take 5.6g of propylene diamine and dissolve it in 75mL of deionized water to prepare a propylene diamine solution with a concentration of 1mol / L. Take 13.2g of ascorbic acid and dissolve it in 50mL of deionized water to prepare an ascorbic acid solution with a concentration of 1mol / L. Use 0.1mol / L hydrochloric acid or NaOH aqueous solution to adjust the pH of the mixed solution to 1.2, and the other steps are the same as in Example 1. The mass ratio of gum arabic to HAuCl4 is 2.5:1 (the ratio of the mass of gum arabic to the molar amount of HAuCl4 is 5g:0.01mol), the mass ratio of ethylphenyl polyethylene glycol to HAuCl4 is 0.09:1, the molar ratio of propylene diamine to HAuCl4 is 3:2, and the molar ratio of ascorbic acid to HAuCl4 is 3:2.

[0076] The morphology of the prepared thin-walled micrometer hollow gold spheres was observed by scanning electron microscopy. Figure 4 As shown, it can be seen that the prepared thin-walled micron hollow gold sphere has a smooth surface, an average particle size of 3 μm, a wall thickness of 100 nm, and it is calculated that the volume of the internal hollow space accounts for 80% of the volume of the gold sphere.

[0077] Example 3

[0078] Take 30g of gum arabic and 1.35g of ethylphenyl polyethylene glycol and dissolve them in 450mL of deionized water to obtain a dispersant solution. Take 5.6g of propylenediamine and dissolve it in 75mL of deionized water to prepare a propylenediamine solution with a concentration of 1mol / L. Take 21.8g of catechin and dissolve it in 50mL of deionized water to prepare a catechin solution with a concentration of 1mol / L. The other steps are the same as in Example 1. The mass ratio of gum arabic to HAuCl4 is 3:1 (the ratio of the mass of gum arabic to the molar amount of HAuCl4 is 6g:0.01mol), the mass ratio of ethylphenyl polyethylene glycol to HAuCl4 is 0.135:1, the molar ratio of propylenediamine to HAuCl4 is 3:2, and the molar ratio of catechin to HAuCl4 is 3:2.

[0079] The morphology of the prepared thin-walled micrometer hollow gold spheres was observed by scanning electron microscopy. Figure 5 As shown, it can be seen that the prepared thin-walled micron hollow gold sphere has a smooth surface, an average particle size of 1.8 μm, a wall thickness of 100 nm, and it is calculated that the volume of the internal hollow space accounts for 70% of the volume of the gold sphere.

[0080] Example 4

[0081] Take 15g of gum arabic and 0.9g of ethylphenyl polyethylene glycol and dissolve them in 450mL of deionized water to obtain a dispersant solution. Take 13.9g of dodecylamine and dissolve them in 75mL of deionized water to prepare a dodecylamine solution with a concentration of 1mol / L. Take 13.2g of ascorbic acid and dissolve them in 50mL of deionized water to prepare an ascorbic acid solution with a concentration of 1mol / L. Use 0.1mol / L of hydrochloric acid or NaOH aqueous solution to adjust the pH of the mixed solution to 1.5, and the other steps are the same as in Example 1. The mass ratio of gum arabic to HAuCl4 is 1.5:1 (the mass ratio of gum arabic to the molar amount of HAuCl4 is 3g:0.01mol), the mass ratio of ethylphenyl polyethylene glycol to HAuCl4 is 0.09:1, the molar ratio of dodecylamine to HAuCl4 is 3:2, and the molar ratio of catechin to HAuCl4 is 3:2.

[0082] The morphology of the prepared thin-walled micrometer hollow gold spheres was observed by scanning electron microscopy. Figure 6 As shown, it can be seen that the prepared thin-walled micron hollow gold sphere has a smooth surface, an average particle size of 1 μm, a wall thickness of 100 nm, and it is calculated that the volume of the internal hollow space accounts for 50% of the volume of the gold sphere.

[0083] pass Figures 1-2 , Figures 4 to 6Combined with Examples 1 to 4, the following conclusions can be drawn: the greater the molar ratio of the protective agent to HAuCl4, the smoother the surface of the sphere; the lower the pH, the larger the average particle size; regardless of the size of the sphere, the wall thickness is 100nm, indicating that during the formation of the hollow sphere, the gold particles generated in the early stage self-assemble into a spherical framework, and under the Ostwald process, the gold atoms gradually grow in the later stage to fill the outer framework and form a thin-walled hollow sphere.

[0084] Comparative Example 1

[0085] 1.5 g of ethylenediamine was dissolved in 75 mL of deionized water to prepare an ethylenediamine solution with a concentration of 0.3 mol / L, and the other steps were the same as those in Example 1. The molar ratio of ethylenediamine to HAuCl4 was 1:2.

[0086] The morphology of the prepared thin-walled micrometer hollow gold spheres was observed by scanning electron microscopy. Figure 7 As shown, it can be seen that the prepared thin-walled micrometer hollow gold sphere has a rough surface with holes. This shows that the amount of ethylenediamine is related to the self-assembly process of gold particles, and at the same time proves that the process of gold particles self-assembling into a spherical framework exists.

[0087] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A thin-walled micron hollow gold sphere, characterized in that: The wall thickness of the thin-walled micron hollow gold sphere is 90-110 nm, and the internal hollow volume of the thin-walled micron hollow gold sphere accounts for 50-90% of the volume of the entire thin-walled micron hollow gold sphere.

2. The thin-walled micron hollow gold sphere according to claim 1, characterized in that: The average particle size of the thin-walled micron hollow gold spheres is 1 to 3 μm.

3. The method for preparing the thin-walled micron hollow gold sphere according to any one of claims 1 to 2, characterized in that: The following steps are involved: The aqueous solution of gum arabic-ethylphenyl polyethylene glycol and the aqueous solution of gold source are mixed, and the obtained mixed solution is mixed with the aqueous solution of organic amine to generate a complex reaction, thereby obtaining a suspension containing the gold-amine coordination compound; The pH value of the suspension containing the gold-amine coordination compound is adjusted to 1-2, and a reducing agent aqueous solution is added to the solution after the pH value is adjusted to cause an oxidation-reduction reaction to obtain the thin-walled micron hollow gold sphere; The molar ratio of the organic amine in the organic amine aqueous solution to the gold ions in the gold source aqueous solution is 1-2:

1.

4. The preparation method according to claim 3, characterized in that: The ratio of the mass of the gum arabic to the molar amount of gold ions in the gold source aqueous solution is 2-7 g:0.01 mol; The mass ratio of the gum arabic to the ethylphenyl polyethylene glycol is 12 to 30:

1.

5. The preparation method according to claim 3, characterized in that: The organic amine in the organic amine aqueous solution includes one or more of ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine and dodecylamine.

6. The preparation method according to claim 3, characterized in that: The reducing agent in the reducing agent aqueous solution includes one or more of caffeic acid, catechin and ascorbic acid.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the reducing agent to the gold ions in the gold source aqueous solution is 1 to 2:

1.

8. The preparation method according to claim 3, characterized in that: The gold source in the gold source aqueous solution is chloroauric acid.

9. The preparation method according to claim 3 or 4, characterized in that: The steps of preparing the aqueous solution of gum arabic-ethylphenyl polyethylene glycol include: dissolving gum arabic in water, and then adding ethylphenyl polyethylene glycol and mixing.

10. The preparation method according to claim 3, characterized in that: After the oxidation-reduction reaction, the method further includes subjecting the obtained product liquid to solid-liquid separation, solid washing and drying.

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