A method and device for synthesizing metal-coated nanoparticles by collision electrochemistry
Through collision electrochemical method without external electrolytes, the problems of nanoparticle agglomeration and surface pollution in electrochemical synthesis are solved, and efficient and green preparation of monodispersed metal nanoparticles are achieved, improving yield and morphological control capabilities.
Patent Information
- Application Number
- CN202211526281.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-01
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2042-12-01
AI Technical Summary
Existing electrochemical synthesis methods are difficult to avoid the agglomeration of nanoparticles in supporting electrolytes, and the use of chemical reducing agents and surfactants may lead to surface contamination, affecting the quality and application of nanomaterials.
Using collision electrochemical method without external electrolytes, the growth solution of conductive nanoseeds and metal precursors is subjected to collision electrochemical treatment. The electrons are provided through the working electrode, so that metal ions form shells on the surface of the nanoseeds, avoid agglomeration and improve yield. .
It realizes efficient and green preparation of monodispersed metal nanoparticles, improves yield and morphological control capabilities, avoids contamination of chemical residues, and improves the application performance of nanomaterials.
Smart Images
Figure CN115772690B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nano-synthesis, in particular to the technical field of nano-particle preparation. Background Art
[0002] High-quality metal nanoparticles (NPs) with controllable size, shape, and composition are the prerequisite for their application in various fields. At present, a variety of methods for the synthesis of metal nanoparticles have been developed, such as ball milling, physical vapor deposition, and chemical synthesis. Among them, chemical synthesis is the most widely used method for synthesizing metal nanoparticles. However, in order to synthesize high-quality metal NPs, chemical synthesis usually requires precise adjustment of reaction kinetics (through reaction temperature and time, reagent addition rate, selection of appropriate reducing agents and precursors, etc.) to regulate the nucleation and particle growth processes. In many cases, the optimal synthesis conditions can only be found through trial and error. In addition, the chemical reducing agents and stabilizers used often bring surface contamination problems, which may hinder the subsequent application of metal nanomaterials.
[0003] Electrochemical synthesis is a green and easy-to-operate synthesis route. This is because it uses electrons as reducing agents, thus avoiding the use of chemical reducing agents. In addition, the reaction kinetics can be easily adjusted over several orders of magnitude by simply changing the electrode potential by a very small degree (e.g., <1V). Due to these advantages, electrochemical synthesis has also been used in the field of synthesis of metal nanomaterials, and the sources of its precursors can be roughly divided into three categories: electrode materials, prefabricated nanomaterials, and metal salt solutions. In the first category (derived from electrode materials), ligand-stabilized lead and bismuth-based perovskite nanocrystals can currently be prepared by anodic dissolution; surface-clean alloy Pt can be prepared by cathodic corrosion. x R yNanoparticles. In the second category (derived from prefabricated nanomaterials), platinum nanospheres and silver films can currently be treated by square wave potentiometry and cyclic voltammetry to obtain tetrahedral platinum nanocubes and silver nanoflowers, respectively. In the more common third category (derived from metal salt solutions), NPs, nanowires, and nanotubes can currently be prepared by electrodeposition on the electrode surface with or without the help of porous templates. We note that existing methods for electrochemical synthesis of metal nanoparticles either only produce products on the electrode surface, or the products are severely aggregated in solution, or require the use of surfactants (whose residues may contaminate the products and ultimately have an adverse effect on their performance) to stabilize the metal nanoparticles. The main challenge of electrochemical synthesis of nanomaterials is the need to balance the high conductivity of the electrolyte solution and the colloidal stability of the nanomaterials exposed therein. Although this challenge can be largely alleviated by reducing the electrolyte concentration, the number of particles that can be stably present in the electrolyte is very small (e.g., concentration <1.1pM), which is prone to problems of low synthesis efficiency and yield. Therefore, the electrochemical synthesis method of nanomaterials still has a large gap in yield and ability to regulate product morphology compared with the more mature chemical synthesis method. Summary of the invention
[0004] The first object of the present invention is to provide a method for collision electrochemical synthesis of monodisperse metal M-coated nanoparticles, aiming to prepare monodisperse metal M-coated nanoparticles efficiently and in high yield based on an electrochemical method.
[0005] The second object of the present invention is to provide a preparation device for implementing the method.
[0006] The third object of the present invention is to provide nano metal particles prepared by the method and applications thereof.
[0007] The existing methods for preparing metal nanoparticles mainly include mechanical ball milling, vapor deposition, chemical method and electrochemical synthesis method. At present, it is difficult for the existing electrochemical preparation method to effectively avoid the problem that nanoparticles are easy to agglomerate in the supporting electrolyte. The chemical method inevitably requires the use of chemical components such as reducing agents and surface ligands, and chemical residues are likely to exist on the surface of the prepared nanoparticles, affecting their quality and use. In view of the current status and problems faced by the preparation of metal nanoparticles, the present invention provides the following new solutions:
[0008] A method for synthesizing monodisperse metal M-coated nanoparticles by collision electrochemistry, wherein a growth solution containing conductive nanoseeds and metal M precursors and a working electrode without an external electrolyte are subjected to collision electrochemical treatment, so that the nanoseeds obtain electrons from the surface of the working electrode and reduce the metal M ions, thereby forming a metal M shell layer on the surface of the nanoseeds to obtain the metal M-coated nanoparticles.
[0009] In the present invention, a growth solution without an added electrolyte (ie, without a supporting electrolyte) is subjected to collision electrochemical treatment, so that monodisperse metal M-coated nanoparticles can be obtained in a green and high-yield manner based on a new improved collision electrochemical concept.
[0010] In the method of the present invention, electrons in the collision electrochemical treatment stage are provided by a working electrode of an external electrochemical circuit; one side of the working electrode is in contact with the electrolyte solution of the electrochemical circuit, and the other side is in contact with the growth solution, and the electrolyte solution and the growth solution are separated by the working electrode.
[0011] The method of the present invention performs collision electrochemical treatment on the nanoseeds immersed in the precursor solution under the condition that the nanoseeds are separated from the electrolyte solution, and the precursor is reduced to atoms and coated on the surface of the nanoseeds. The method of the present invention can avoid the agglomeration of nanoparticles in the growth system, and can obtain metal M-coated nanoparticles in a green and high-yield manner without the need for auxiliary chemical reagents.
[0012] In the present invention, there are no special requirements for the electrolyte solution, for example, it can be a solution of at least one of an acidic electrolyte, an alkaline electrolyte, and a neutral electrolyte. The acidic electrolyte is, for example, at least one of HClO4 and H2SO4; the neutral electrolyte is, for example, at least one of NaClO4, KClO4, Na2SO4, K2SO4, NaNO3, and KNO3; the alkaline electrolyte is, for example, at least one of NaOH and KOH; the solvent in the electrolyte solution can include at least one of water, ethanol, and propanol. The concentration of the electrolyte in the electrolyte solution is, for example, 0.01 to 10 mol / L, preferably 0.05 to 1 mol / L; more preferably 0.4 to 0.6 mol / L.
[0013] In the present invention, the working electrode may be a conventional conductive material in the industry, for example, double-sided conductive ITO glass.
[0014] In the present invention, the nano seeds are nanoparticles with conductive properties. Preferably, the nano seeds are at least one of conductive metal nanoparticles, conductive carbon nanoparticles, and surface-sensitized non-metallic seeds with metallized active sites.
[0015] Preferably, the conductive metal nanoparticles are at least one of gold, silver, palladium, platinum, etc.;
[0016] Preferably, the conductive carbon nanoparticles are at least one of graphite, carbon black, etc.;
[0017] Preferably, the non-metallic seed is at least one of SiO2, diamond, polystyrene, etc.;
[0018] Preferably, the D50 (median particle size) of the nano seeds can be adjusted according to the preparation requirements, for example, 1-1000 nm, preferably 10-100 nm, and more preferably 15-45 nm.
[0019] In the growth solution of the present invention, the concentration of the nano seeds can be adjusted according to the preparation requirements, preferably 1 to 100 mg / L, more preferably 10 to 60 mg / L.
[0020] The metal M precursor is a compound that can be reduced to the corresponding metal M by receiving electrons;
[0021] Preferably, the metal M precursor is at least one of HAuCl4, HPdCl4, and HPtCl6;
[0022] Preferably, in the growth solution, the concentration of the metal M precursor is less than or equal to the critical coagulation concentration; preferably 0.01 to 30 mmol / L, more preferably 0.05 to 10 mmol / L; more preferably 0.1 to 10 mmol / L, and more preferably 0.3 to 0.8 mmol / L. In the present invention, unlike the conventional electrochemical preparation process, it is not necessary to achieve the purpose of reducing agglomeration by infinitely diluting the solution, and can achieve green preparation of monodisperse nanoparticles at higher concentrations, which can improve preparation efficiency and preparation effect.
[0023] In the present invention, the growth solution is a solution composed of nano seeds, metal M precursors, and solvents;
[0024] Preferably, the solvent in the growth solution is water or a mixed solution of water and an organic solvent.
[0025] In the present invention, in the growth system without an external electrolyte, the combined control of the potential range is further coordinated to further improve the performance of the prepared metal M-coated nanoparticles.
[0026] Preferably, the collision electrochemical treatment is a constant potential treatment;
[0027] Preferably, the potential range of the collision electrochemical treatment (relative to a saturated calomel electrode) is 0 to 1 V, preferably 0.1 to 0.9 V, and more preferably 0.4 to 0.9 V. In the present invention, at the voltage, the preparation effect of the process of the present invention can be further improved.
[0028] Preferably, the collision electrochemical treatment can also be performed by constant current treatment, and the potential range of the current is 0.01 to 8 mA / cm 2 ; In the present invention, under the current density described above, the preparation effect of the process of the present invention can be further synergistically improved.
[0029] The time of the collision electrochemical treatment can be adjusted according to the needs of nanoparticle preparation, for example, 0.1 to 100,000 s, preferably 1,000 to 8,000 s; more preferably 4,000 to 6,500 s.
[0030] The present invention also provides a device for synthesizing monodisperse metal M-coated nanoparticles by collision electrochemistry for implementing the method, comprising an asymmetrically designed electrolytic cell and a working electrode separator;
[0031] The working electrode separator divides the electrolytic cell chamber into a growth chamber for holding a growth solution and a potential control chamber for holding an electrolyte solution, which are independent of each other;
[0032] The potential control chamber is provided with a working electrode and a counter electrode; the working electrode and the counter electrode are respectively connected to the working electrode and the counter electrode of the electrochemical workstation to form a circuit loop;
[0033] Preferably, a reference electrode is also provided in the potential control chamber, and is connected to a reference electrode of the electrochemical workstation.
[0034] The device described in the present invention can separate the electrolyte solution system and the growth solution system, and can use the circuit loop of the potential control chamber to make the working electrode partition carry electrons on the surface of the growth chamber. Based on the collision between the nanoseed and the working electrode, the nanoseed is charged, and then the metal ions of the precursor are induced to uniformly reduce on the surface of the nanoseed to form a metal layer, and then the metal M-coated nanoparticles are prepared. The device described in the present invention can obtain monodisperse nanometal particles with high yield based on an electrochemical method, avoid the agglomeration of nanoparticles, and in addition, it can also avoid the addition of surfactants, which helps to improve the application performance of the prepared nanoparticles.
[0035] The present invention also provides a metal M-coated nanoparticle prepared by the method, which is a monodisperse nanoparticle comprising a nano seed core and a metal M shell layer coated on the surface of the nano seed core.
[0036] The present invention also provides an application of the metal M-coated nanoparticles prepared by the method, which are used to prepare materials for at least one of catalysis, sensing and medical treatment.
[0037] The traditional electrochemical synthesis system contains an undivided electrolytic cell, three electrodes (i.e., working electrode, counter electrode, and reference electrode) and a supporting electrolyte solution as a current channel and reaction medium. In order to minimize the voltage loss caused by the solution resistance, the concentration of the electrolyte solution is relatively high, usually higher than 0.1M. Although this relatively high electrolyte concentration has no effect on the stability of soluble electroactive substances (such as ions and small molecules), this situation does not apply to charge-stabilized nanoparticles. According to the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, charge-stabilized nanoparticles are prone to instability and aggregation in electrolyte solutions. This is because the electrolyte can effectively shield the electrostatic repulsion between particles, resulting in the dominant van der Waals attraction between them. The electrolyte concentration that causes colloidal particles to begin to aggregate is called the critical coagulation concentration. From the perspective of colloidal stability, the concentration of the electrolyte solution in the nanoparticle synthesis reaction system not only limits the maximum size of the obtained particles, but also limits their yield. Therefore, the traditional electrochemical synthesis method often synthesizes nanoparticles on the surface of the electrode. Synthesis in solution requires relying on high concentrations of surfactants to provide stability or can only obtain nanoparticles with extremely low concentrations. In order to overcome the problem of easy aggregation of metal M-coated nanoparticles in electrolyte solutions in traditional electrochemical synthesis methods, the present invention provides a new method for synthesizing monodisperse metal M-coated nanoparticles by collision electrochemistry and its implementation device, which is an electrolytic cell consisting of two compartments. One of the compartments is a potential control chamber, similar to a traditional electrochemical cell, and contains an electrolytic chamber of a working electrode, a counter electrode (preferably containing a reference electrode) and an electrolyte solution. The energy of the electrons on the working electrode can be adjusted by adjusting the potential of the working electrode relative to the reference electrode. The other compartment is a growth chamber containing a growth solution, which is separated from the potential control chamber by a working electrode and shares the working electrode. Therefore, when the electroactive substance (such as a conductive nanoseed) in the growth chamber collides with the working electrode, the electroactive substance can accept the electrons on the working electrode and complete the electrochemical reaction. Since there is no supporting electrolyte, the method of the present invention allows the nanoseeds to grow as single, dispersed particles in the growth solution, and the concentration of the metal precursor in the growth solution can in principle be as high as the critical coagulation concentration of the prepared metal-coated nanoparticles. Therefore, the designed collision electrochemical synthesis method allows the growth solution concentration to be comparable to that in conventional chemical synthesis, that is, the yield of synthesized nanoparticles is comparable to that in chemical synthesis.
[0038] Beneficial effects:
[0039] 1. The method of the present invention allows electrochemical reactions to occur in electrolyte-free solutions, so that the synthesized metal M-coated nanoparticles can achieve a yield comparable to that of ordinary chemical synthesis methods. In addition, it is easy to produce local supersaturation only around the NPs that collide (because only during the collision can the colliding NPs accept electrons from the electrode and reduce the metal ions near them), rather than uniform supersaturation in the bulk solution as produced by ordinary chemical synthesis methods. Therefore, the reaction kinetics and the morphology of the resulting product can be easily adjusted by simply changing the concentration of the precursor.
[0040] 2. The method of the present invention has the advantages of simple operation, green and environmental protection, and can be operated under atmospheric environment, room temperature and mild solution conditions.
[0041] 3. The metal M-coated nanoparticles prepared by the method of the present invention have a clean surface and controllable morphology and have good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below.
[0043] Figure 1 Schematic diagram of the device structure for preparing metal M-coated nanoparticles by collision electrochemistry.
[0044] Figure 2 TEM image of gold nanoparticles prepared by collision electrochemistry;
[0045] in, Figure 2 In the figure, A is the TEM image of AuNPs synthesized by collision growth of 15 nm Au seeds in 0.3 mM HAuCl4 solution at a potential of 0.84 V vs. SCE; B is the TEM image of AuNPs after collision growth.
[0046] Figure 3 TEM and EDS mapping images of Au@PdNPs with thin and continuous Pd shell prepared by collision electrochemistry;
[0047] in, Figure 3 In the figure, a is the TEM image of Au@PdNPs with a thin and continuous Pd shell synthesized by collision growth of 45 nm Au seeds in 0.3 mM H2PdCl4 solution at a potential of 0.45 V; b is its corresponding EDS mapping image.
[0048] Figure 4 TEM and EDS mapping images of Au@PdNPs with thick and rough Pd shell prepared by collision electrochemistry;
[0049] in, Figure 4 In the figure, A is the TEM image of Au@PdNPs with thick and rough Pd shell synthesized by collision growth of 45 nm Au seeds in 0.7 mM H2PdCl4 solution at a potential of 0.45 V; B is the corresponding EDS mapping image.
[0050] Figure 5 TEM and EDS mapping images of Au@PtNPs with thin and continuous Pt shell prepared by collision electrochemistry;
[0051] in, Figure 5 In the figure, A is the TEM image of Au@PtNPs with thin and continuous Pt shell synthesized by collision growth of 45 nm Au seeds in 0.3 mM H2PtCl6 solution at a potential of 0.40 V; B is its corresponding EDSmapping image.
[0052] Figure 6 TEM and EDS mapping images of Au@PtNPs with thick and rough Pt shell prepared by collision electrochemistry;
[0053] in, Figure 6 In the figure, A is the TEM image of Au@PtNPs with thick and rough Pt shells synthesized by collision growth of 45 nm Au seeds in 0.7 mM H2PtCl6 solution at a potential of 0.40 V; B is its corresponding EDS mappin image. DETAILED DESCRIPTION
[0054] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.
[0055] The method provided by the present invention is to obtain gold seeds (AuNPs) through the classic Frens method (i.e., reducing chloroauric acid in an environment where trisodium citrate is used as a stabilizer and a reducing agent), and under the condition that the gold seeds are separated from the electrolyte solution, the precursor is reduced and deposited on the surface of the gold nanoparticles by collision electrochemistry, thereby preparing metal M-coated nanoparticles of different particle sizes and different morphologies.
[0056] The specific steps of the method of the present invention can be referred to as follows:
[0057] (a) Au seed dispersion was prepared by the Frens method, with a concentration of approximately 57.91 μg NPs / mL;
[0058] The solvent used to disperse AuNPs is water, and the stabilizer is trisodium citrate added before the synthesis reaction.
[0059] (b) Place a certain amount of seed dispersion and a certain amount of electrolyte solution in Figure 1 Two sides of the reaction apparatus are shown.
[0060] (c) The reference electrode and the counter electrode are placed in the electrolyte solution, and the conductive separator serves as the working electrode.
[0061] (d) A certain amount of precursor solution is added to the Au seed dispersion and electrochemically treated at a certain potential for a certain time.
[0062] In this step, the electrolyte solution can be obtained by dissolving / diluting an electrolyte in a solvent;
[0063] In one embodiment of the present invention, the electrolyte may be an acidic electrolyte (e.g., perchloric acid, sulfuric acid, etc.), an alkaline electrolyte (e.g., sodium hydroxide, potassium hydroxide), or a neutral electrolyte (e.g., sodium sulfate, sodium perchlorate, etc.);
[0064] Preferably, the electrolyte is sodium perchlorate (NaClO4);
[0065] Preferably, the solvent may be one or more of organic or inorganic solvents such as water, ethanol, propanol, etc.
[0066] In one embodiment of the present invention, the concentration of the electrolyte solution is 0.05 to 1 mol / L; preferably, the concentration of the electrolyte solution is 0.4 to 0.6 mol / L.
[0067] In one embodiment of the present invention, the concentration of the precursor solution is 0.05 to 1 mmol / L; preferably, the concentration of the precursor solution is 0.3 to 0.7 mmol / L.
[0068] In one embodiment of the present invention, the diameter of the gold nanoparticles is 10 to 100 nm; preferably, the diameter of the gold nanoparticles is 15 to 45 nm.
[0069] In one embodiment of the present invention, the reference electrode is a saturated calomel electrode, a mercurous sulfate electrode, a standard hydrogen electrode or other electrodes that can be used as a reference electrode;
[0070] The counter electrode is a noble metal electrode, such as a platinum electrode (platinum sheet) or the like.
[0071] In one embodiment of the present invention, the electrochemical treatment is a constant potential or constant current treatment.
[0072] In one embodiment of the present invention, the electrochemical treatment potential is 0 to 1 V, and the treatment potential can be adjusted according to the reference electrode and the counter electrode used;
[0073] Meanwhile, the electrochemical treatment time is 0.1 to 100,000 s, and preferably, the electrochemical treatment time is 3,000 to 6,000 s.
[0074] In the present invention, the device for implementing the method is shown in Figure 1 , which includes an electrolytic cell and a working electrode (in the following case, double-sided conductive ITO glass is used as an example) to divide the electrolytic cell into a growth chamber and a potential control chamber that are independent of each other. The growth chamber contains a growth solution; the potential control chamber contains an electrolyte solution. The growth solution and the electrolyte solution are independent of each other and do not communicate with each other.
[0075] The potential control chamber also contains a reference electrode and a counter electrode inserted into the electrolyte solution. The working electrode, reference electrode and counter electrode are connected with the working electrode, reference electrode and counter electrode of the electrochemical workstation to form a circuit loop.
[0076] In the present invention, the working electrode and the counter electrode are energized to form a circuit loop in the potential control chamber, and the surface of the working electrode in the growth chamber forms an electron-donating surface. When the nanoseeds in the growth solution collide with the working electrode, electrons are transferred from the working electrode to the nanoseeds, and the precursors in the growth solution are reduced to metal atoms on the surface of the nanoseeds to form a metal layer.
[0077] Example 1
[0078] The collision electrochemical synthesis of AuNPs was carried out as follows:
[0079] Step 1: Prepare 15 nm Au seed dispersion by Frens method, with a concentration of about 57.91 μg NPs / mL.
[0080] Step 2: Place 49.3 mL of 15 nm Au seed dispersion and 50 mL of 0.5 M NaClO4 solution in Figure 1 The two sides of the reaction apparatus are shown. 0.7 mL of 0.024 M HAuCl4 solution was added to one side of the gold seed dispersion.
[0081] Step 3: react at a potential of 0.84 V for 6000 s.
[0082] Example 2
[0083] The collision electrochemical synthesis of Au@PdNPs with a thin and continuous Pd shell was carried out as follows:
[0084] Step 1: Prepare 45 nm Au seed dispersion by Frens method, with a concentration of about 57.91 μg NPs / mL.
[0085] Step 2: Place 35 mL of 45 nm Au seed dispersion and 50 mL of 0.5 M NaClO4 solution in Figure 1 Add 15 mL of 1 mM H2PdCl4 solution to one side of the gold seed dispersion.
[0086] Step 3: react at a potential of 0.45 V for 6000 s.
[0087] Example 3
[0088] The collision electrochemical synthesis of Au@PdNPs with thick and rough Pd shell was carried out as follows:
[0089] Step 1: Prepare 45 nm Au seed dispersion by Frens method, with a concentration of about 57.91 μg NPs / mL.
[0090] Step 2: Place 15 mL of 45 nm Au seed dispersion and 50 mL of 0.5 M NaClO4 solution in Figure 1 The two sides of the reaction apparatus are shown. 35 mL of 1 mM H2PdCl4 solution was added to one side of the gold seed dispersion.
[0091] Step 3: react at a potential of 0.45 V for 6000 s.
[0092] Example 4
[0093] The collision electrochemical synthesis of Au@PtNPs with a thin and continuous Pt shell was carried out as follows:
[0094] Step 1: Prepare 45 nm Au seed dispersion by Frens method, with a concentration of about 57.91 μg NPs / mL.
[0095] Step 2: Place 49.2 mL of 45 nm Au seed dispersion and 50 mL of 0.5 M NaClO4 solution in Figure 1 The two sides of the reaction apparatus are shown. 0.8 mL of 19.3 mM H2PtCl6 solution was added to one side of the gold seed dispersion.
[0096] Step 3: react at a potential of 0.40 V for 6000 s.
[0097] Example 5
[0098] The collision electrochemical synthesis of Au@PtNPs with thick and rough Pt shell was carried out as follows:
[0099] Step 1: Prepare 45 nm Au seed dispersion by Frens method, with a concentration of about 57.91 μg NPs / mL.
[0100] Step 2: Place 48.1 mL of 45 nm Au seed dispersion and 50 mL of 0.5 M NaClO4 solution in Figure 1 The two sides of the reaction apparatus are shown. 1.9 mL of 19.3 mM H2PtCl6 solution was added to one side of the gold seed dispersion.
[0101] Step 3: react at a potential of 0.4 V for 6000 s.
[0102] Experimental Example 1
[0103] The Au@PdNPs with a thin and continuous Pd shell synthesized by collision electrochemistry in Example 2 were used as experimental materials, and electron scanning microscopy and electron scattering spectrum were used for characterization. The results are as follows: Figure 3 shown.
[0104] TEM images of Au@PdNPs show that a thin and continuous shell of approximately 1 to 2 nm thick covers the Au seeds ( Figure 3 a), which is mainly composed of Pd element ( Figure 3 b).
[0105] Although the present invention has been illustrated and described with specific embodiments, it will be appreciated that many other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended to include all such changes and modifications within the scope of the present invention in the appended claims.
Claims
1. A method for synthesizing monodisperse metal M-coated nanoparticles by collision electrochemistry, It is characterized in that A growth solution containing conductive nanoseeds and metal M precursors without an external electrolyte and a working electrode are subjected to collision electrochemical treatment, so that the nanoseeds obtain electrons from the surface of the working electrode and reduce the metal M ions, thereby forming a metal M shell on the surface of the nanoseeds to obtain the metal M-coated nanoparticles; the metal M precursor is a compound that can be reduced by electrons to the corresponding metal M, wherein the metal M is at least one of Au, Pd, and Pt; The electrons in the collision electrochemical treatment stage are provided by the working electrode of an external electrochemical circuit; One side of the working electrode is in contact with the electrolyte solution of the electrochemical circuit, and the other side is in contact with the growth solution. The electrolyte solution and the growth solution are separated by the working electrode.
2. The method according to claim 1, It is characterized in that The electrolyte solution is a solution of at least one of an acidic electrolyte, an alkaline electrolyte, and a neutral electrolyte.
3. The method according to claim 2, It is characterized in that The acid electrolyte is HClO 4 , H 2 SO 4 At least one of; The neutral electrolyte is NaClO 4 , KClO 4 、Na 2 SO 4 , K 2 SO 4 、NaNO 3 、KNO 3 At least one of; The alkaline electrolyte is at least one of NaOH and KOH.
4. The method according to claim 3, It is characterized in that The solvent in the electrolyte solution includes at least one of water, ethanol and propanol.
5. The method according to claim 4, It is characterized in that The concentration of the electrolyte in the electrolyte solution is 0.1 to 10 mol / L.
6. The method according to claim 1, It is characterized in that The conductive nano seeds are at least one of conductive metal nanoparticles, conductive carbon nanoparticles, and surface-sensitized non-metallic seeds with metallized active sites.
7. The method according to claim 6, It is characterized in that The conductive metal nanoparticles are at least one of gold, silver, palladium and platinum; The conductive carbon nanoparticles are at least one of graphite and carbon black; The non-metallic seed is SiO 2 , diamond, and polystyrene.
8. The method according to claim 6, It is characterized in that The size of the nano seeds is 1 nm-10 mm.
9. The method according to claim 1, It is characterized in that The metal M precursor is HAuCl 4 , H 2 PdCl 4 , H 2 PtCl 6 At least one of .
10. The method according to claim 1, It is characterized in that In the growth solution, the concentration of the metal M precursor is less than or equal to the critical coagulation concentration of the prepared particles.
11. The method according to claim 10, It is characterized in that In the growth solution, the concentration of the metal M precursor is 0.01 to 30 mmol / L.
12. The method according to claim 10, It is characterized in that In the growth solution, the concentration of the metal M precursor is 0.1~10mmol / L.
13. The method according to claim 10, It is characterized in that The concentration of the metal M precursor in the growth solution is 0.3~0.8 mmol / L.
14. The method of claim 1, It is characterized in that The growth solution is a solution composed of nano seeds, metal M precursors and solvents.
15. The method of claim 1, It is characterized in that The solvent in the growth solution is water or a mixed solution of water and an organic solvent.
16. The method according to any one of claims 1 to 15, It is characterized in that The collision electrochemical treatment is a constant potential or constant current treatment.
17. A device for synthesizing monodisperse metal M-coated nanoparticles by collision electrochemistry, which implements the method according to any one of claims 1 to 16, It is characterized in that including an electrolytic cell and a working electrode separator of asymmetrical design; The working electrode separator divides the electrolytic cell chamber into a growth chamber for holding a growth solution and a potential control chamber for holding an electrolyte solution, which are independent of each other; The potential control chamber is provided with a working electrode and a counter electrode; the working electrode and the counter electrode are respectively connected to the wiring of the working electrode and the counter electrode of the electrochemical workstation to form a circuit loop.
18. A device for synthesizing monodisperse metal M-coated nanoparticles by collision electrochemistry according to the method of claim 17, It is characterized in that A reference electrode is also provided in the potential control chamber and is connected to the reference electrode of the electrochemical workstation.
19. A metal M-coated nanoparticle prepared by the method according to any one of claims 1 to 16, It is characterized in that The nanoparticles are monodispersed nanoparticles including a nano seed core and a metal M shell layer coated on the surface of the nano seed core.
20. Use of metal M-coated nanoparticles prepared by the method according to any one of claims 1 to 16, It is characterized in that The material is used to prepare at least one of catalysis, sensing and medical materials.