CN109834262B

CN109834262B - Au with controllable number and size of atoms19Ag4Synthesis method of alloy nanocluster

Info

Publication number: CN109834262B
Application number: CN201711230323.XA
Authority: CN
Inventors: 黄家辉; 任秀清; 刘超; 林欣章
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2017-11-29
Filing date: 2017-11-29
Publication date: 2021-03-30
Anticipated expiration: 2037-11-29
Also published as: CN109834262A

Abstract

Au with controllable number and size of atoms₁₉Ag₄The method can be used for synthesizing AuAg nanoclusters of different sizes in a large scale. Dissolving chloroauric acid and silver nitrate in dichloromethane, stirring for a period of time, adding a ligand to react for thirty minutes, adding sodium borohydride to reduce to obtain zero-valent AuAg alloy nanoparticles, and finally obtaining Au with accurate atomic number along with the lengthening of reaction time₁₉Ag₄An alloy nanocluster. Au with accurate atomic number and different sizes is obtained by adjusting the atomic ratio of gold and silver₁₉Ag₄An alloy nanocluster. The method has feasibility and simple operation, and Au with different sizes can be obtained by changing the atomic ratio of gold and silver₁₉Ag₄A nanocluster.

Description

Au with controllable number and size of atoms19Ag4Synthesis method of alloy nanocluster

The technical field is as follows:

the invention belongs to Au₁₉Ag₄The invention discloses a method for preparing Au with controllable atomic number and size by simple preparation₁₉Ag₄A nanocluster.

Background art:

in recent years, the alloy nanocluster is widely concerned by people as a new member of a nanometer material, and the electronic structure and the surface composition of the alloy are changed due to the interaction among atoms, so that the chemical or optical properties of the alloy nanocluster are changed, and the alloy nanocluster has great application potential in the aspects of catalysis, sensing, biological imaging, drug delivery, cancer treatment and the like.

The metal nanocluster is a metal particle with the size of less than 2nm and a quantum size effect, generally has a core-shell structure formed by metal and ligands, the metal serves as a core and the ligands serve as shell layers, and the physicochemical properties of the metal cluster can be controlled by controlling factors such as size, morphology, composition or functional groups. Currently, a series of bimetallic nanoclusters are synthesized, for example, Zhengnan peak group successfully synthesizes Au by using cationic ligand₂₄Ag₂₀Alloy cluster and obtain its crystal structure (J.Am.chem.Soc.,2015,137, 4324-4327), which was successfully synthesized in 2015 in the Zhuman group [ Ag₄₆Au₂₄(SR)₃₂](BPh₄)₂(Sci.adv.,2015,1: e 1500441). Although the synthesis types are more, two problems still exist in the current research of alloy clusters: firstly, the doped crystal structure is relatively complex, so that the structure is difficult to determine; secondly, the factors influencing the interaction between the ligand and the metal are difficult to determine.

Controlling the size of the alloy nanoclusters with different and precise atomic numbers is a challenge at present; for some nano-cluster synthesis methods, the steps are complicated and the operation is complex. Aiming at the problem, the patent explores a simple and easy synthesis method for preparing Au₁₉Ag₄Nanoclusters of Au prepared in a single system using a simple one-step process₁₉Ag₄A nanocluster. The method can be generally applied to synthesis of the noble metal alloy nanocluster.

The invention content is as follows:

the invention aims to provide Au with controllable synthetic atom number and size₁₉Ag₄The preparation method of the nano-cluster is feasible and simple to operate. Is mainly used for preparing Au with controllable number of atoms and controllable size in the same system₁₉Ag₄The alloy nanoclusters are less than 2nm in size and have accurate atomic numbers. The Au provided by the invention has controllable atom number and size₁₉Ag₄The preparation of the nano-cluster comprises the following specific steps: adding 10-50 mg of HAuCl₄.4H₂O and AgNO₃Dissolving the Au powder in 10-20 mL of dichloromethane, stirring for 20-50 minutes, adding a ligand, stirring for half an hour to one hour, and finally adding sodium borohydride for reduction to obtain Au₁₉Ag₄Nano cluster, and the molar ratio of the chloroauric acid to the silver nitrate is 1: 0.05-0.25. When the ratio of the ligand to the metal source is 3-5: 1, the product is Au with controllable number of atoms after reduction by sodium borohydride₁₉Ag₄Nanoclusters, reaction time depends on the uv-vis absorption spectrum of the sample during the experiment. To prepare high purity nanoclusters, the product dissolved in dichloromethane is spun dry, centrifuged, extracted, and then spun dry.

Obtaining the number and the size of atoms by using a simple one-step reaction methodControllable Au₁₉Ag₄Nano-clusters, and nano-clusters with different sizes can be prepared by adjusting the proportion of the two metal sources.

Compared with the reported preparation method of the gold and silver nanocluster, the preparation method has the following advantages:

a) the invention synthesizes Au₁₉Ag₄The nano-cluster can be used for preparing various other alloy nano-clusters.

b) The invention can control the proportion of two metal sources, and prepare Au with controllable number of atoms and size₁₉Ag₄A nanocluster.

c) The one-step synthesis method of the invention prepares Au₁₉Ag₄The nano-cluster is simple to operate and easy to control.

Description of the drawings:

FIG. 1 is a chart of the UV-VIS absorption spectrum of the product obtained in example 1.

Fig. 2 is a graph of the uv-vis absorption spectrum of the AuAg nanocluster prepared in example 2.

Detailed Description

The invention is described in more detail below with reference to examples:

example 1: au coating₁₉Ag₄Synthesis of nanoclusters

50mg of HAuCl₄.4H₂O mixed AgNO₃Dissolved in 20mL of dichloromethane (HAuCl)₄.4H₂O and AgNO₃At a molar ratio of 1:0.125), adding a thiol ligand at a ratio of 5:1, stirring at room temperature for thirty minutes until the reaction solution becomes a precipitate, then dissolving 10mg of sodium borohydride in 1mL of water at 4 ℃, adding the above solution to reduce, and the precipitate slowly becomes brown. After the reaction is carried out for 1-5 days, the absorption peak of the product is characterized by ultraviolet visible absorption spectrum, and the generation of Au is proved₁₉Ag₄A nanocluster. And finally purifying the alloy nanoclusters, spin-drying the product dissolved in dichloromethane, washing the product for 3 times by using methanol, extracting the product by using dichloromethane, and finally spin-drying to obtain the nano-gold nanocluster shown in the figure 1.

Example 2: synthesis of AuAg nanoclusters

50mg of HAuCl₄.4H₂O mixed AgNO₃Dissolved in 20mL of a solventIn chloromethane (HAuCl)₄.4H₂O and AgNO₃At a molar ratio of 1:0.3, adding a thiol ligand at a ratio of 5:1, stirring at room temperature for thirty minutes until the reaction solution becomes a precipitate, then dissolving 10mg of sodium borohydride in 1mL of water at 4 ℃, adding the solution to reduce, and slowly turning the precipitate brown to start the reaction. After the reaction is carried out for 1 to 5 days, the absorption peak of the product is characterized by an ultraviolet visible absorption spectrum, and the ratio of silver is increased to 0.3: 1 result, so Au is not present₁₉Ag₄Generation of alloy nanoparticles as shown in fig. 2, example 2 prepared an ultraviolet-visible absorption spectrum of an AuAg nanocluster.

Claims

1. Au with controllable number and size of atoms₁₉Ag₄The method for synthesizing the nano-cluster is characterized by comprising the following steps: the method comprises the following steps: dissolving 10-50 mg of chloroauric acid and silver nitrate in 10-20 mL of dichloromethane, stirring for 20-50 minutes, adding a ligand, stirring for half an hour to one hour until the solution becomes a precipitate, and finally adding 10-20 mg of sodium borohydride for reduction to obtain Au₁₉Ag₄Nano cluster, and the molar ratio of the chloroauric acid to the silver nitrate is 1: 0.05-0.25.

2. Au with controllable atomic number and size according to claim 1₁₉Ag₄The method for synthesizing the nanoclusters is characterized in that when the molar ratio of a ligand to chloroauric acid to a silver nitrate metal source is 3-5: 1, and the ligand is reduced by sodium borohydride, the product is Au with controllable atom number and size₁₉Ag₄A nanocluster.

3. Au with controllable atomic number and size according to claim 1₁₉Ag₄The method for synthesizing the nanoclusters is characterized in that the reaction time depends on the ultraviolet-visible absorption spectrum of a sample in the experimental process.

4. Au with controllable atomic number and size according to claim 1₁₉Ag₄NanoclusterCharacterized in that, in order to prepare high purity nanoclusters, Au dissolved in methylene chloride is used₁₉Ag₄And (4) spin-drying, centrifuging, extracting and spin-drying the nano-cluster product.

5. Au with controllable atomic number and size according to claim 1₁₉Ag₄The method for synthesizing the nano-clusters is characterized in that the nano-clusters with different sizes are prepared by adjusting the ratio of chloroauric acid to silver nitrate, and the size range is 1.3-1.9 nm.

6. Au with controllable atomic number and size according to claim 1₁₉Ag₄The method for synthesizing the nano-cluster is characterized in that the ligand is 2-phenethyl mercaptan; the molar ratio of the ligand to the chloroauric acid to the silver nitrate is 3-5: 1.