Method for preparing gold single atoms by using pulse laser and gold single atom preparation system

Abstract

The invention relates to the technical field of pulse laser application, in particular to a method for preparing gold single atoms through pulse laser and a gold single atom preparing system.The method for preparing the gold single atoms through the pulse laser comprises the steps that a gold nanoparticle solution is provided; and a pulse laser sequence is irradiated into the gold nanoparticle solution in parallel, the pulse laser energy flux is 4.2-8.5 J / cm < 2 >, the irradiation time is 10-15 min, and the gold monatomic solution is obtained. The method for preparing the gold monatomic solution by using the pulse laser is simple in technological process, and the gold monatomic solution can be efficiently prepared.

Description

Technical Field

[0001] The present application relates to the technical field of pulse laser application, and in particular to a method for preparing single gold atoms using pulse laser and a system for preparing single gold atoms. Background Art

[0002] Single atom catalysts (SACs) have excellent material utilization and catalytic activity, and have high research value in the field of chemistry and chemical engineering. At present, a lot of research has been done on the theoretical calculation of single atom catalysis, but in terms of experiments, the preparation process of single atom catalysts is difficult, which limits the application and promotion of single atom catalysts.

[0003] Common single-atom catalysts are prepared by chemical methods, specifically by high-temperature carbonization. This method is limited by the long preparation process and high cost and cannot be widely used in the chemical industry. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present application provides a method for preparing single gold atoms using pulsed lasers and a system for preparing single gold atoms, which can efficiently prepare single gold atom solutions.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: providing a method for preparing single gold atoms using pulsed laser, comprising providing a gold nanoparticle solution; irradiating a pulsed laser sequence in parallel to the gold nanoparticle solution, with a pulsed laser energy flux of 4.2 to 8.5 J / cm2 and an irradiation time of 10 to 15 minutes, to obtain a single gold atom solution.

[0006] In a specific embodiment, before irradiating the pulse laser sequence into the gold nanoparticle solution in parallel, the method further includes controlling the temperature of the gold nanoparticle solution at 5-7° C. using a water bath.

[0007] In a specific embodiment, providing a gold nanoparticle solution includes preparing a gold seed solution; mixing a first tetrachloroauric acid solution, a first surfactant solution, and a first reducing agent solution to obtain a first mixed solution; mixing the first mixed solution with the gold seed solution and letting the mixture stand to obtain the gold nanoparticle solution; wherein the volume ratio of the first mixed solution to the gold seed solution is (55-100):1.

[0008] In a specific embodiment, the step of mixing the first mixed solution with the gold seed solution and letting the mixture stand to obtain the gold nanoparticle solution comprises: mixing the first mixed solution with the gold seed solution and letting the mixture stand for 40 to 80 minutes to obtain the gold nanoparticle solution; in the first mixed solution, the molar concentration of the first surfactant is 0.15 to 0.35 mmol / L, the molar concentration of tetrachloroauric acid is 0.05 to 0.15 mol / L, and the molar concentration of the first reducing agent is 0.03 to 0.06 mol / L; the first surfactant solution comprises hexadecyltrimethylammonium chloride solution, and the first reducing agent solution comprises ascorbic acid solution.

[0009] In a specific embodiment, the mixing of the first tetrachloroauric acid solution, the first surfactant solution, and the first reducing agent solution to obtain the first mixed solution includes: injecting 0.05-0.25 mol / L of the first tetrachloroauric acid solution into water to obtain a diluted second tetrachloroauric acid solution; mixing 0.1-0.3 mol / L of the first surfactant solution and the second tetrachloroauric acid solution to obtain a second mixed solution; stirring the second mixed solution until it becomes transparent brown-yellow, and adding 0.05-0.20 mol / L of the first reducing agent solution to the second mixed solution to obtain the first mixed solution.

[0010] In a specific embodiment, the preparation of the gold seed solution includes: mixing a third tetrachloroauric acid solution, a second surfactant solution, and a second reducing agent solution and letting them stand to obtain a gold seed solution; wherein the molar concentrations of tetrachloroauric acid, the second surfactant, and the second reducing agent in the gold seed solution are 0.05-0.35 mmol / L, 0.05-0.15 mol / L, and 0.35-0.85 mmol / L, respectively.

[0011] In a specific embodiment, the mixing of the third tetrachloroauric acid solution, the second surfactant solution, and the second reducing agent solution and letting stand comprises: pouring the third tetrachloroauric acid solution into the second surfactant solution and mixing to obtain a third mixed solution; stirring until the third mixed solution is transparent brown-yellow, adding the second reducing agent solution at one time and stirring rapidly for 1 to 5 minutes to obtain a fourth mixed solution; letting the fourth mixed solution stand for 2 to 5 hours to obtain the gold seed solution.

[0012] In a specific embodiment, the second surfactant solution includes hexadecyltrimethylammonium bromide solution, the second reducing agent solution includes sodium glacial borohydride solution, the concentration of the third tetrachloroauric acid solution is 0.02-0.04 mol / L, the concentration of the second surfactant solution is 0.2-0.4 mol / L, and the concentration of the second reducing agent solution is 0.02-0.04 mol / L.

[0013] In order to solve the above technical problems, another technical solution adopted in the present application is: to provide a gold single atom preparation system, characterized in that it is used to implement the method for preparing gold single atoms using pulsed laser as described in any one of the above specific embodiments; the gold single atom preparation system includes a pulsed laser, a precision attenuation wheel, an electrically controlled shutter, and a reaction container filled with a gold nanoparticle solution; the precision attenuation wheel and the electrically controlled shutter are arranged between the emission end of the pulsed laser and the reaction container, and the pulsed laser emitted by the emission end can pass through the precision attenuation wheel and the electrically controlled shutter to irradiate the gold nanoparticle solution in the reaction container in the form of parallel light.

[0014] In a specific embodiment, the gold single atom preparation system further includes a heat-insulating container capable of accommodating the reaction container, wherein the heat-insulating container is provided with a heat-insulating material, and the heat-insulating material is used to control the temperature of the gold nanoparticle solution at 5-7°C.

[0015] The beneficial effect of the present application is that compared with the prior art, the implementation method of the present application first prepares a gold nanoparticle solution, and then irradiates the gold nanoparticles, thereby causing the gold atoms to detach from the surface of the gold nanoparticles and then enter the solution to form a gold single-atom solution. The method of irradiating gold nanoparticles is more efficient than the method of high-temperature carbonization, and the cost is reduced. In addition, compared with the preparation of single-atom solutions by irradiating bulk materials, the size of gold nanoparticles becomes smaller after irradiation, and its adsorption capacity for gold single atoms is significantly reduced, and the properties of the obtained gold single-atom solution are also better. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of an embodiment of a gold single atom preparation system of the present application;

[0017] Figure 2 This is a schematic diagram of the process of irradiating a gold nanoparticle solution to prepare a gold single atom solution in the present application;

[0018] Figure 3 This is an electron microscope image of the gold nanoparticle solution provided in the embodiment of the present application before irradiation treatment;

[0019] Figure 4 is an electron microscope image of the gold nanoparticle solution after irradiation treatment provided in the embodiment of the present application;

[0020] Figure 5 It is a schematic flowchart of the process of the method for preparing gold nanoparticles provided in the present application;

[0021] Figure 6 It is a schematic flow chart of the method for synthesizing a gold nanoparticle solution provided in the present application;

[0022] Figure 7It is a schematic flowchart of the process of the method for preparing the gold seed solution provided in this application.

[0023] Reference numerals:

[0024] 1. Pulse laser; 2. Precision attenuation wheel; 3. Electronically controlled shutter; 4. Reflector; 5. Reaction vessel; 6. Insulation container; 7. Pulse laser; 8. Gold nanoparticles; 9. Single gold atom. DETAILED DESCRIPTION

[0025] In the present invention, the terms "disposed", "provided with", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0028] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] Single atom catalysts (SACs) have excellent material utilization and catalytic activity, and have high research value in the field of chemistry and chemical engineering. At present, a lot of research has been done on the theoretical calculation of single atom catalysis, but in terms of experiments, the preparation process of single atom catalysts is difficult, which limits the application and promotion of single atom catalysts.

[0031] Common single-atom catalysts are prepared by chemical methods, specifically by high-temperature carbonization. This method has certain limitations in its application in the chemical industry due to its long preparation process and high cost.

[0032] In the patent "Metal Single Atom Catalyst and Preparation Method Thereof" (Chinese Patent, Application Number: 202010202772.9), a method for preparing single atom catalysts by continuous laser excitation of bulk metal materials is proposed. This method has poor quality of single atoms formed due to the low peak power density of the continuous laser and the large heat-affected zone of the processed material.

[0033] In order to improve or solve the above technical problems, the inventors of the present application have proposed at least the following embodiments after long-term research.

[0034] The present application embodiment provides a method for preparing single gold atoms using pulsed laser. In this embodiment, the method for preparing single gold atoms using pulsed laser may include the following steps:

[0035] Step 1: Provide a gold nanoparticle solution.

[0036] The gold nanoparticle solution includes gold nanoparticles. Optionally, the gold nanoparticles can be spherical gold nanoparticles.

[0037] Step 2: irradiate the gold nanoparticle solution with a pulse laser sequence in parallel, with a pulse laser energy flux of 4.2 to 8.5 J / cm2 and an irradiation time of 10 to 15 minutes, to obtain a gold single atom solution.

[0038] In the method for preparing gold single atoms using pulsed laser provided in this embodiment, the method of irradiating gold nanoparticles is more efficient than the method of high-temperature carbonization, and the cost is reduced, which is conducive to the promotion of gold single-atom catalysts in practical applications and effectively increases the practicality of single-atom catalysts. In addition, compared with the preparation of single-atom solutions by irradiating bulk materials, the size of gold nanoparticles becomes smaller after irradiation, and its adsorption capacity for gold single atoms is significantly reduced, and the properties of the obtained gold single-atom solution are also better. Among them, the pulsed laser has a higher peak power density. By controlling the energy flux and irradiation time of the pulsed laser, the detachment of gold single atoms is effectively promoted, and the concentration of metal single-atom solutions can be accurately controlled. The concentration of gold single atoms in the prepared gold single-atom solution can be predicted, so that a gold single-atom solution that meets the requirements can be obtained.

[0039] In the process of using pulsed laser to irradiate gold nanoparticle solution and prepare gold single atom solution, the pulsed laser irradiates the gold nanoparticles by using high energy to cause the gold atoms on the surface of the gold nanoparticles to vaporize. The vaporized gold atoms enter the liquid phase environment and are cooled, and then remain in the liquid phase to form a gold single atom solution. Due to the high temperature at the moment of vaporization, the temperature of the liquid phase system will inevitably rise, affecting the effect of cooling the gold single atoms.

[0040] In a specific embodiment of the present application, before the pulse laser sequence is irradiated in parallel into the gold nanoparticle solution in step 2, the temperature of the gold nanoparticle solution can be controlled at 5-7° C. by using a water bath. Thus, the temperature of the gold nanoparticle solution is controlled in a relatively low range by using a water bath, thereby improving the cooling effect of the liquid phase system on the vaporized gold single atoms, and achieving the purpose of rapid cooling and forming a stable gold single atom solution system.

[0041] See also Figure 5 , Figure 5 : is a schematic flow chart of the method for preparing gold nanoparticles provided in the present application. In a specific embodiment of the present application, step 1 of providing a gold nanoparticle solution may specifically include the following steps:

[0042] S100: preparing a gold seed solution.

[0043] The gold seed growth method is a method of using smaller gold nanoclusters as seeds to gradually grow larger gold nanoclusters, which can be achieved through a 2-electron (e-) reduction process. When gold nanoparticles need to be prepared, the gold seed growth method is a common method. Before using the gold seed growth method, a gold seed solution needs to be prepared to obtain a gold seed solution containing small-sized gold nanoclusters.

[0044] S200: mixing a first tetrachloroauric acid solution, a first surfactant solution, and a first reducing agent solution to obtain a first mixed solution.

[0045] On the basis of the prepared gold seed solution, a first tetrachloroauric acid solution, a first surfactant solution, and a first reducing agent solution are mixed to obtain a first mixed solution for growing small-sized gold nanoclusters into larger-sized gold nanoparticles.

[0046] In this step, the first tetrachloroauric acid solution is used to provide gold elements for the growth of gold nanoclusters, and the first reducing agent solution is used to reduce the tetrachloroauric acid in the first tetrachloroauric acid solution, so that under the auxiliary action of the first surfactant in the first surfactant solution, the reduced gold single atoms can be used for the growth of gold nanoclusters in the gold seed solution to form larger gold nanoparticles.

[0047] S300: Mix the first mixed solution with the gold seed solution and let it stand to obtain a gold nanoparticle solution.

[0048] During the static process, the reduced gold atoms attach to the surface of the gold nanoclusters in the gold seed solution, causing the size of the gold nanoclusters to gradually increase, thereby obtaining a gold nanoparticle solution.

[0049] By the method provided in the present embodiment, it is possible to first prepare a gold nanoparticle solution using a gold seed growth method, and then irradiate the gold nanoparticle solution, so that the gold single atom is separated from the surface of the gold nanoparticle under the effect of irradiation, and then can enter the solution to form a gold single atom solution. The method of irradiating gold nanoparticles is more efficient than the means of high-temperature carbonization, and the cost has been reduced, which is conducive to the promotion of gold single atom catalysts in practical applications, and effectively increases the practicality of single atom catalysts. In addition, compared with the preparation of single atom solution by irradiating bulk materials, the size of the gold nanoparticles becomes smaller after irradiation, and its adsorption capacity for gold single atoms is significantly reduced, and the properties of the obtained gold single atom solution are also better.

[0050] In a specific embodiment of the present application, step S300 can specifically be to mix the first mixed solution with the gold seed solution and let it stand for 40 to 80 minutes to obtain a gold nanoparticle solution. Wherein, in the first mixed solution, the molar concentration of the first surfactant can be 0.15 to 0.35 mmol / L, the molar concentration of tetrachloroauric acid can be 0.05 to 0.15 mol / L, and the molar concentration of the first reducing agent can be 0.03 to 0.06 mol / L. Optionally, the first surfactant solution can specifically include a hexadecyltrimethylammonium chloride solution, and the first reducing agent solution can include an ascorbic acid solution. By controlling the standing time after the first mixed solution is mixed with the gold seed solution, as well as the molar concentration range of each component in the first mixed solution, the size and morphology of the obtained gold nanoparticles can be controlled, and a gold nanoparticle solution that meets the requirements of subsequent processes can be obtained, which helps to achieve control of the concentration of the metal single atom solution.

[0051] Among them, ascorbic acid solution is used as the first reducing agent solution, which can gently reduce the gold element in tetrachloroauric acid, is suitable for the growth of gold nanoclusters in the gold seed solution into gold nanoparticles, and provides suitable prerequisites for the subsequent preparation of gold single atom solution.

[0052] See also Figure 6 , Figure 6 : is a schematic flow chart of the method for synthesizing a gold nanoparticle solution provided by the present application. The present application embodiment provides a method for preparing a single gold atom using a pulsed laser. In this embodiment, step S200 may specifically include the following steps:

[0053] S201: injecting 0.05-0.25 mol / L of a first tetrachloroauric acid solution into water to obtain a diluted second tetrachloroauric acid solution.

[0054] S202: Mixing a first surfactant solution (0.1-0.3 mol / L) and a second tetrachloroauric acid solution to obtain a second mixed solution.

[0055] S203: Stir the second mixed solution until it becomes transparent brown-yellow, and add 0.05-0.20 mol / L of the first reducing agent solution to the second mixed solution to obtain a first mixed solution.

[0056] The method provided in this embodiment can use the first tetrachloroauric acid solution, the first surfactant solution and the first reducing agent solution to prepare the first mixed solution, forming a solution environment suitable for the growth of gold nanoparticles, thereby obtaining a gold nanoparticle solution that meets the requirements of subsequent processes, which helps to achieve the control of the concentration of the metal single atom solution.

[0057] In a specific embodiment of the present application, step S100 may specifically include mixing a third tetrachloroauric acid solution, a second surfactant solution, and a second reducing agent solution and standing to obtain a gold seed solution. The molar concentrations of tetrachloroauric acid, the second surfactant, and the second reducing agent in the gold seed solution may be 0.05-0.35 mmol / L, 0.05-0.15 mol / L, and 0.35-0.85 mmol / L, respectively.

[0058] Through the method provided in this embodiment, a gold seed solution can be prepared with a suitable ratio, thereby forming small-sized gold nanoclusters in the solution, obtaining a gold seed solution that meets the requirements of subsequent processes, and helping to control the concentration of the metal single atom solution.

[0059] See also Figure 7 , Figure 7: is a schematic flow chart of the method for preparing a gold seed solution provided in the present application. In the step, the present application embodiment provides a method for preparing a single gold atom using a pulsed laser. In this embodiment, the step S100 of preparing a gold seed solution may specifically include the following steps:

[0060] S101: Pour the third tetrachloroauric acid solution into the second surfactant solution and mix them to obtain a third mixed solution.

[0061] S102: Stirring until the third mixed solution is transparent brown-yellow, adding the second reducing agent solution at one time and stirring rapidly for 1 to 5 minutes to obtain a fourth mixed solution.

[0062] S103: The fourth mixed solution is allowed to stand for 2 to 5 hours to obtain a gold seed solution.

[0063] Through the method provided in this embodiment, a gold seed solution can be prepared with a suitable preparation process, thereby forming small-sized gold nanoclusters in the solution, obtaining a gold seed solution that meets the requirements of subsequent processes, and facilitating the control of the concentration of the metal single atom solution.

[0064] In a specific embodiment of the present application, the second surfactant solution may specifically include a hexadecyl trimethyl ammonium bromide solution. The second reducing agent solution may include a sodium glacial borohydride solution. The concentration of the third tetrachloroauric acid solution may be 0.02 to 0.04 mol / L, the concentration of the second surfactant solution may be 0.2 to 0.4 mol / L, and the concentration of the second reducing agent solution may be 0.02 to 0.04 mol / L.

[0065] Through the structure provided in the embodiment of the present application, a gold seed solution can be prepared with a suitable ratio, thereby forming small-sized gold nanoclusters in the solution, obtaining a gold seed solution that meets the requirements of subsequent processes, and helping to achieve control of the concentration of the metal single atom solution.

[0066] like Figure 1 , Figure 2 As shown, Figure 1 It is a structural schematic diagram of an embodiment of a gold single atom preparation system of the present application. Figure 2 This is a schematic diagram of the process of irradiating a gold nanoparticle solution to prepare a gold single atom solution. Figure 2The figure shows the gold nanoparticles 8 in the gold nanoparticle solution emitted by the pulse laser 7, and the gold single atoms 9 in the gold single atom solution after being treated by the pulse laser 7. The present application also provides a gold single atom preparation system, which is used to implement the method for preparing gold single atoms using pulse laser as described in any of the above specific embodiments. The gold single atom preparation system can specifically include a pulse laser 1, a precision attenuation wheel 2, an electrically controlled shutter 3, and a reaction vessel 5 filled with a gold nanoparticle solution. The precision attenuation wheel 2 and the electrically controlled shutter 3 are arranged between the emission end of the pulse laser 1 and the reaction vessel 5, and the pulse laser 7 emitted by the emission end can pass through the precision attenuation wheel 2 and the electrically controlled shutter 3 to irradiate the gold nanoparticle solution in the reaction vessel 5 in the form of parallel light.

[0067] In the gold single atom preparation system provided in this embodiment, the method of irradiating gold nanoparticles 8 is more efficient than the high-temperature carbonization method, and the cost is reduced, which is conducive to the promotion of catalysts based on gold single atoms 9 in practical applications, and effectively increases the practicality of single-atom catalysts. In addition, compared with the preparation of single-atom solutions by irradiating bulk materials, the size of gold nanoparticles 8 becomes smaller after irradiation, and its adsorption capacity for gold single atoms 9 is significantly reduced, and the properties of the obtained gold single-atom solution are also better. Among them, the pulsed laser 7 has a higher peak power density. When the gold nanoparticle solution is irradiated with the pulsed laser 7 with controlled energy flux, it can effectively promote the detachment of gold single atoms 9, and control the length of irradiation time, so that the concentration of gold single atoms 9 in the obtained gold single-atom solution can be expected, so as to obtain a single-atom catalyst that meets the requirements of catalytic effect.

[0068] The precision attenuation wheel 2 is used to control the energy flux of the pulse laser 7, and the electric shutter 3 is used to control the irradiation time of the pulse laser 7. The two can adjust the working parameters of the laser to meet the requirements of processing the gold single atom solution. The pulse laser 1, the precision attenuation wheel 2, and the electric shutter 3 can be connected in sequence.

[0069] like Figure 1 In the structure shown, the optical path of the pulsed laser 7 processing the gold nanoparticle solution may not be completely straight. In the actual structural design of the gold single atom preparation system, the reflector 4 can be used to make the optical path turn, so as to meet the needs of actual applications. The setting position of the reflector 4 is not fixed, and can be adjusted according to the position where the optical path needs to turn, making the structure of the gold single atom preparation system more flexible. For example, Figure 1In the figure, the reflecting mirror 4 is arranged between the electric-controlled shutter 3 and the reaction container 5, so that the pulse laser 7 emitted horizontally through the electric-controlled shutter 3 is turned under the action of the reflecting mirror 4, and is incident downward in the vertical direction into the reaction container 5, so that the side wall of the reaction container 5, the side wall of the heat preservation container 6, and the heat preservation material in the heat preservation container 6 will not affect the energy of the pulse laser 7, thereby improving the working efficiency of the gold single atom preparation system.

[0070] In the process of using the pulse laser 7 to irradiate the gold nanoparticle solution and prepare the gold single atom solution, when the pulse laser 7 irradiates the gold nanoparticle 8, the gold atoms on the surface of the gold nanoparticle 8 are vaporized by using high energy, and the vaporized gold atoms enter the liquid phase environment and are cooled, and then remain in the liquid phase to form a gold single atom solution. Due to the high temperature at the moment of vaporization, the temperature of the liquid phase system is inevitably increased, affecting the effect of cooling the gold single atoms 9.

[0071] Therefore, in a specific embodiment of the present application, the gold single atom preparation system may further include a heat preservation container 6 that can accommodate the reaction container 5. The heat preservation container 6 is provided with a heat preservation material, and the heat preservation material can be used to control the temperature of the gold nanoparticle solution at 5 to 7° C. Thus, the reaction container 5 is placed in the heat preservation container 6 provided with the heat preservation material, and the temperature of the gold nanoparticle solution in the reaction container 5 is controlled in a lower range by the heat preservation material, thereby improving the cooling effect of the liquid phase system on the vaporized gold single atom 9, and achieving the purpose of rapid cooling and forming a stable gold single atom solution system.

[0072] Using the gold single atom preparation system provided in the embodiment of the present application, the method for preparing gold single atoms using pulsed laser can be implemented by the following steps:

[0073] (1) An optical path for processing gold single atoms using a pulsed laser 7 is constructed, the optical path comprising a pulsed laser 1, a precision attenuation wheel 2, an electrically controlled shutter 3, a reflector 4, a beaker 5 containing a gold nanoparticle solution, and a heat-insulating container 6 containing a heat-insulating material. The heat-insulating material may be a fluid material such as water or oil that can be used for temperature control. In this embodiment, water is selected as the heat-insulating material.

[0074] The pulse laser 7 emitted by the pulse laser 1 can be irradiated in parallel to the gold nanoparticle solution 5 through the precision attenuation wheel 2, the electric shutter 3, and the reflector 4 in sequence. The container 6 filled with 5-7°C water provides a water bath environment for the gold nanoparticle solution, completing the construction of the pulse laser 7 processing gold single atom system.

[0075] (2) adjusting the precision attenuation wheel so that the energy flux of the pulsed laser 7 incident on the gold nanoparticle solution is 4.2 to 8.5 J / cm2;

[0076] (3) The irradiation time is controlled to be 10 to 15 minutes by adjusting the electronically controlled shutter to complete the preparation process of the gold single atom solution.

[0077] The method for preparing the gold nanoparticle solution in the embodiment of the present application may specifically include the following steps:

[0078] (1) injecting a third tetrachloroauric acid solution with a molar concentration of 0.02-0.04 mol / L into a hexadecyltrimethylammonium bromide solution with a molar concentration of 0.2-0.4 mol / L, mixing at 20-25°C, the solution presents a transparent brownish yellow color, then adding a 0.02-0.04 mol / L glacial sodium borohydride solution at one time, stirring rapidly for 1-5 minutes, the solution presents a whitish brownish yellow color, and then standing at 20-25°C for 2-5 hours to obtain a gold seed solution. The molar concentrations of tetrachloroauric acid, hexadecyltrimethylammonium bromide and sodium borohydride in the gold seed solution are 0.05-0.35 mmol / L, 0.05-0.15 mol / L and 0.35-0.85 mmol / L, respectively.

[0079] (2) A first tetrachloroauric acid solution with a molar concentration of 0.05 to 0.25 mol / L is injected into water to obtain a diluted second tetrachloroauric acid solution, a hexadecyltrimethylammonium chloride solution with a molar concentration of 0.1 to 0.3 mol / L and the diluted tetrachloroauric acid solution are warmed and stirred, and the solution presents a transparent brown-yellow color, and then an ascorbic acid solution with a molar concentration of 0.05 to 0.20 mol / L is added to obtain a colorless mixed solution, in which the molar concentrations of hexadecyltrimethylammonium chloride, tetrachloroauric acid and ascorbic acid are 0.15 to 0.35 mmol / L, 0.05 to 0.15 mol / L and 0.03 to 0.06 mol / L, respectively.

[0080] (3) Adding the gold seed solution obtained in step (1) to the colorless mixed solution, leaving it to stand for 1 hour, to obtain a gold nanoparticle solution, wherein the volume ratio of the gold seed solution to the colorless mixed solution in the gold nanoparticle solution is 1:(55-100).

[0081] The following describes an embodiment of the method provided by the present application.

[0082] Embodiment 1:

[0083] (1) Synthetic gold seed solution:

[0084] A tetrachloroauric acid solution with a molar concentration of 0.02 mol / L was injected into a hexadecyltrimethylammonium bromide solution with a molar concentration of 0.2 mol / L, and the mixture was mixed at 23°C. The solution showed a transparent brown-yellow color. Then, a 0.02 mol / L glacial sodium borohydride solution was added at once, and the mixture was rapidly stirred for 3 minutes. The solution showed a whitish brown-yellow color. The solution was then allowed to stand at 23°C for 2 hours to obtain a gold seed solution. The molar concentrations of tetrachloroauric acid, hexadecyltrimethylammonium bromide and sodium borohydride in the gold seed solution were 0.05 mmol / L, 0.05 mol / L and 0.4 mmol / L, respectively.

[0085] (2) Synthesis of gold nanoparticle solution by gold seed solution growth method:

[0086] A tetrachloroauric acid solution with a molar concentration of 0.05 mol / L is injected into water to obtain a diluted tetrachloroauric acid solution, a hexadecyl trimethyl ammonium chloride solution with a molar concentration of 0.1 mol / L and the diluted tetrachloroauric acid solution are warmly stirred, the solution presents a transparent brown-yellow color, and then an ascorbic acid solution with a molar concentration of 0.08 mol / L is added to obtain a colorless mixed solution, wherein the molar concentrations of hexadecyl trimethyl ammonium chloride, tetrachloroauric acid and ascorbic acid in the colorless mixed solution are 0.15 mmol / L, 0.08 mol / L and 0.03 mol / L respectively. The gold seed solution of step (1) is added to the colorless mixed solution, and the mixture is allowed to stand for 1 hour to obtain a gold nanoparticle solution, wherein the volume ratio of the gold seed solution to the colorless mixed solution in the gold nanoparticle solution is 1:60.

[0087] (3) A pulsed laser sequence was parallelly irradiated into the gold nanoparticle solution. The pulsed laser energy flux was 4.4 J / cm2, the irradiation time was 10 min, and the water bath temperature was 5°C to obtain a gold single atom solution with a concentration of 0.14 mol / L.

[0088] like Figure 3 , Figure 4 As shown, Figure 3 This is an electron microscope image of the gold nanoparticle solution provided in the example of the present application before irradiation treatment. Figure 4 This is an electron microscope image of the gold nanoparticle solution after irradiation treatment provided in the examples of the present application.

[0089] The femtosecond laser used in this embodiment is a titanium sapphire laser produced by Coherent, model Astrella, with a central wavelength of 800nm, a pulse width of 35fs, a maximum repetition frequency of 1000Hz, a maximum single pulse energy of 7mJ, and a Gaussian light intensity distribution.

[0090] It can be clearly seen that the morphology and size of the gold nanoparticles in the gold nanoparticle solution changed significantly after irradiation. The gold nanoparticles, which were originally close to 10nm in size and had a nearly spherical outer contour, formed a dispersed point structure of extremely small size in the system after pulse laser irradiation. This shows that gold atoms can be peeled off from gold nanoparticles under the action of pulse laser, thereby achieving the purpose of preparing gold single atom solution.

[0091] It should be noted that Figure 3 , Figure 4 The shape and size of the gold sphere particles are only for example. The actual shape and size of the gold sphere particles before and after irradiation are not Figure 3 , Figure 4 The shapes and sizes shown are limitations.

[0092] Embodiment 2:

[0093] (1) Synthetic gold seed solution:

[0094] A tetrachloroauric acid solution with a molar concentration of 0.03 mol / L was injected into a hexadecyltrimethylammonium bromide solution with a molar concentration of 0.3 mol / L, and the mixture was mixed at 22°C. The solution was transparent brown-yellow. Then, a 0.03 mol / L glacial sodium borohydride solution was added at once, and the mixture was rapidly stirred for 5 minutes. The solution was whitish brown-yellow, and then allowed to stand at 22°C for 3 hours to obtain a gold seed solution. The molar concentrations of tetrachloroauric acid, hexadecyltrimethylammonium bromide and sodium borohydride in the gold seed solution were 0.10 mmol / L, 0.10 mol / L and 0.6 mmol / L, respectively.

[0095] (2) Synthesis of gold nanoparticle solution by gold seed solution growth method:

[0096] A tetrachloroauric acid solution with a molar concentration of 0.2 mol / L is injected into water to obtain a diluted tetrachloroauric acid solution, a hexadecyl trimethyl ammonium chloride solution with a molar concentration of 0.25 mol / L and the diluted tetrachloroauric acid solution are warmly stirred, the solution presents a transparent brown-yellow color, and then an ascorbic acid solution with a molar concentration of 0.15 mol / L is added to obtain a colorless mixed solution, wherein the molar concentrations of hexadecyl trimethyl ammonium chloride, tetrachloroauric acid and ascorbic acid in the colorless mixed solution are 0.3 mmol / L, 0.15 mol / L and 0.05 mol / L respectively. The gold seed solution of step (1) is added to the colorless mixed solution, and the mixture is allowed to stand for 1 hour to obtain a gold nanoparticle solution, wherein the volume ratio of the gold seed solution to the colorless mixed solution in the gold nanoparticle solution is 1:80.

[0097] (3) A pulsed laser sequence was irradiated in parallel into the gold nanoparticle solution. The pulsed laser energy flux was 6 J / cm2, the irradiation time was 12 min, and the water bath temperature was 6°C, to obtain a gold single atom solution with a concentration of 0.16 mol / L.

[0098] Embodiment 3:

[0099] (1) Synthetic gold seed solution:

[0100] A tetrachloroauric acid solution with a molar concentration of 0.04 mol / L was injected into a hexadecyltrimethylammonium bromide solution with a molar concentration of 0.4 mol / L, and the mixture was mixed at 24°C. The solution was transparent brown-yellow. Then, a 0.04 mol / L glacial sodium borohydride solution was added at once, and the mixture was rapidly stirred for 4 minutes. The solution was whitish brown-yellow, and then allowed to stand at 24°C for 4 hours to obtain a gold seed solution. The molar concentrations of tetrachloroauric acid, hexadecyltrimethylammonium bromide and sodium borohydride in the gold seed solution were 0.3 mmol / L, 0.15 mol / L and 0.8 mmol / L, respectively.

[0101] (2) Synthesis of gold nanoparticle solution by gold seed solution growth method:

[0102] A tetrachloroauric acid solution with a molar concentration of 0.25 mol / L is injected into water to obtain a diluted tetrachloroauric acid solution, a hexadecyl trimethyl ammonium chloride solution with a molar concentration of 0.25 mol / L and the diluted tetrachloroauric acid solution are warmly stirred, the solution presents a transparent brown-yellow color, and then an ascorbic acid solution with a molar concentration of 0.10 mol / L is added to obtain a colorless mixed solution, wherein the molar concentrations of hexadecyl trimethyl ammonium chloride, tetrachloroauric acid and ascorbic acid in the colorless mixed solution are 0.35 mmol / L, 0.1 mol / L and 0.06 mol / L respectively. The gold seed solution of step (1) is added to the colorless mixed solution, and the mixture is allowed to stand for 1 hour to obtain a gold nanoparticle solution, wherein the volume ratio of the gold seed solution to the colorless mixed solution in the gold nanoparticle solution is 1:75.

[0103] (3) A pulsed laser sequence was parallelly irradiated into the gold nanoparticle solution, the pulsed laser energy flux was 8.5 J / cm2, the irradiation time was 15 min, and a gold single atom solution with a concentration of 0.22 mol / L was obtained.

[0104] Embodiment 4:

[0105] (1) Synthetic gold seed solution:

[0106] A tetrachloroauric acid solution with a molar concentration of 0.04 mol / L was injected into a hexadecyltrimethylammonium bromide solution with a molar concentration of 0.4 mol / L, and the mixture was mixed at 25°C. The solution was transparent brown-yellow. Then, a 0.03 mol / L glacial sodium borohydride solution was added at once, and the mixture was rapidly stirred for 1 minute. The solution was whitish brown-yellow, and then allowed to stand at 25°C for 2 hours to obtain a gold seed solution. The molar concentrations of tetrachloroauric acid, hexadecyltrimethylammonium bromide and sodium borohydride in the gold seed solution were 0.05 mmol / L, 0.1 mol / L and 0.65 mmol / L, respectively.

[0107] (2) Synthesis of gold nanoparticle solution by gold seed solution growth method:

[0108] A tetrachloroauric acid solution having a molar concentration of 0.25 mol / L is injected into water to obtain a diluted tetrachloroauric acid solution, a hexadecyl trimethyl ammonium chloride solution having a molar concentration of 0.3 mol / L and the diluted tetrachloroauric acid solution are warmly stirred, the solution presents a transparent brownish yellow color, and an ascorbic acid solution having a molar concentration of 0.2 mol / L is added to obtain a colorless mixed solution, wherein the molar concentrations of hexadecyl trimethyl ammonium chloride, tetrachloroauric acid and ascorbic acid in the colorless mixed solution are 0.35 mmol / L, 0.15 mol / L and 0.03 mol / L, respectively. The gold seed solution of step (1) is added to the colorless mixed solution, and the mixture is allowed to stand for 1 hour to obtain a gold nanoparticle solution, wherein the volume ratio of the gold seed solution to the colorless mixed solution in the gold nanoparticle solution is 1:100.

[0109] (3) A pulsed laser sequence was parallelly irradiated into the gold nanoparticle solution, the pulsed laser energy flux was 4.5 J / cm2, the irradiation time was 10 min, and a gold single atom solution with a concentration of 0.15 mol / L was obtained.

[0110] The above is only a specific implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for preparing single gold atoms using pulsed laser, characterized in that: include: providing a gold nanoparticle solution; A pulse laser sequence is irradiated in parallel into the gold nanoparticle solution, the pulse laser energy flux is 4.2 to 8.5 J / cm2, and the irradiation time is 10 to 15 minutes to obtain a gold single atom solution.

2. After obtaining the gold nanoparticle solution and before irradiating the gold nanoparticle solution with a pulse laser sequence in parallel, the method further comprises: The temperature of the gold nanoparticle solution was controlled at 5-7° C. using a water bath.

3. The method for preparing single gold atoms using pulsed laser according to claim 1, characterized in that: Providing a gold nanoparticle solution comprises: Prepare gold seed solution; Mixing a first tetrachloroauric acid solution, a first surfactant solution, and a first reducing agent solution to obtain a first mixed solution; The first mixed solution and the gold seed solution are mixed and allowed to stand to obtain the gold nanoparticle solution; wherein the volume ratio of the first mixed solution to the gold seed solution is (55-100):

1.

4. The method for preparing single gold atoms using pulsed laser according to claim 3, characterized in that: The step of mixing the first mixed solution with the gold seed solution and allowing the mixture to stand to obtain the gold nanoparticle solution comprises: The first mixed solution is mixed with the gold seed solution and allowed to stand for 40 to 80 minutes to obtain the gold nanoparticle solution; in the first mixed solution, the molar concentration of the first surfactant is 0.15 to 0.35 mmol / L, the molar concentration of tetrachloroauric acid is 0.05 to 0.15 mol / L, and the molar concentration of the first reducing agent is 0.03 to 0.06 mol / L; The first surfactant solution includes a cetyltrimethylammonium chloride solution, and the first reducing agent solution includes an ascorbic acid solution.

5. The method for preparing single gold atoms using pulsed laser according to claim 3, characterized in that: The mixing of the first tetrachloroauric acid solution, the first surfactant solution, and the first reducing agent solution to obtain the first mixed solution comprises: Injecting 0.05-0.25 mol / L of the first tetrachloroauric acid solution into water to obtain a diluted second tetrachloroauric acid solution; Mixing a 0.1-0.3 mol / L first surfactant solution and the second tetrachloroauric acid solution to obtain a second mixed solution; The second mixed solution is stirred until it becomes transparent brown-yellow, and 0.05-0.20 mol / L of the first reducing agent solution is added to the second mixed solution to obtain the first mixed solution.

6. The method for preparing single gold atoms using pulsed laser according to claim 3, characterized in that: The preparation of the gold seed solution comprises: mixing the third tetrachloroauric acid solution, the second surfactant solution, and the second reducing agent solution and allowing to stand to obtain a gold seed solution; The molar concentrations of tetrachloroauric acid, the second surfactant and the second reducing agent in the gold seed solution are 0.05-0.35 mmol / L, 0.05-0.15 mol / L and 0.35-0.85 mmol / L respectively.

7. The method for preparing single gold atoms using pulsed laser according to claim 6, characterized in that: The mixing of the third tetrachloroauric acid solution, the second surfactant solution, and the second reducing agent solution and allowing to stand comprises: pouring the third tetrachloroauric acid solution into the second surfactant solution and mixing to obtain a third mixed solution; Stirring until the third mixed solution is transparent brown-yellow, adding the second reducing agent solution all at once and stirring rapidly for 1 to 5 minutes to obtain a fourth mixed solution; The fourth mixed solution is allowed to stand for 2 to 5 hours to obtain the gold seed solution.

8. The method for preparing single gold atoms using pulsed laser according to claim 7, characterized in that: The second surfactant solution includes hexadecyltrimethylammonium bromide solution, the second reducing agent solution includes sodium glacial borohydride solution, the concentration of the third tetrachloroauric acid solution is 0.02-0.04 mol / L, the concentration of the second surfactant solution is 0.2-0.4 mol / L, and the concentration of the second reducing agent solution is 0.02-0.04 mol / L.

9. A gold single atom preparation system, characterized in that: Used to implement the method for preparing single gold atoms using pulsed laser according to any one of claims 1 to 8; The gold single atom preparation system comprises a pulse laser (1), a precision attenuation wheel (2), an electrically controlled shutter (3), and a reaction container (5) containing a gold nanoparticle solution; the precision attenuation wheel (2) and the electrically controlled shutter (3) are arranged between the emission end of the pulse laser (1) and the reaction container (5); the pulse laser (7) emitted by the emission end can pass through the precision attenuation wheel (2) and the electrically controlled shutter (3) to irradiate the gold nanoparticle solution in the reaction container (5) in the form of parallel light.

10. The gold single atom preparation system according to claim 9, characterized in that: It also comprises a heat-insulating container (6) capable of accommodating the reaction container (5), wherein the heat-insulating container (6) is provided with a heat-insulating material, and the heat-insulating material is used to control the temperature of the gold nanoparticle solution at 5-7°C.

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