Preparation method of palladium-gold-copper three-metal mesoporous nanoparticles

Abstract

The invention provides a preparation method of palladium-gold-copper tri-metal mesoporous nanoparticles. Comprising the following steps: preparing a precursor mixed solution containing potassium tetrachloropalladate, copper chloride dehydrate and potassium chloroaurate, adding poloxamer F127 under magnetic stirring, adding L-ascorbic acid after the poloxamer F127 is fully dispersed, and continuously stirring for two hours at normal temperature and normal pressure; and centrifuging and washing to obtain the palladium-gold-copper three-metal mesoporous nanoparticles. The method has the advantages of being simple and efficient in operation, mild in preparation condition, environmentally friendly and the like, directional synthesis of a dandelion-shaped structure with three-dimensional channels is achieved through synchronous reduction of a multi-metal precursor on the basis of a one-pot method strategy, phase separation limitation of traditional multi-metal particles can be broken through, and by means of the synergistic effect of palladium, gold and copper, the three-dimensional channels of the dandelion-shaped structure with the three-dimensional channels are obtained. The active sites and the electron transmission efficiency are remarkably improved, so that the material is endowed with excellent performance.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of metal nanomaterials, and particularly to a method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles. Background Art

[0002] Due to their high specific surface area, adjustable pore size distribution, and abundant surface active sites, mesoporous nanomaterials have shown broad application prospects in the fields of catalysis, energy storage, biomedicine, etc. In recent years, multi-metal nanoparticles have attracted much attention due to their component synergistic effects. For example, the alloy structure of palladium (Pd) and gold (Au) has been proven to significantly improve catalytic activity and stability, and is widely used in fuel cell catalysts, organic synthesis reactions, and degradation of environmental pollutants, etc.

[0003] Currently, the preparation methods of multi-metal mesoporous nanoparticles mainly include template method, solvothermal method, and electrochemical deposition method, etc. However, the traditional template method needs to remove the template through high temperature or strong corrosion conditions, which easily causes aggregation of metal particles and collapse of pore channels, destroying the orderliness of mesopores; the solvothermal method is difficult to achieve synchronous nucleation and uniform growth of trimetals due to the reduction kinetic differences of different metal precursors, and often forms non-ideal core-shell or heterogeneous structures, resulting in insufficient exposure of surface active sites. In addition, existing electrochemical deposition methods mostly rely on strong reducing agents (such as sodium borohydride) or organic protecting agents (such as polyvinylpyrrolidone) to control the morphology, but the residues of such reagents will block the mesoporous channels, affecting the mass transfer efficiency, and the post-treatment is cumbersome.

[0004] Both palladium-gold metal nanoparticles use precious metals. Precious metals are scarce and costly resources, and the surface active area of palladium-gold metal nanoparticles is small and the catalytic activity is low. How to reduce the cost and further improve the performance through component optimization has become an important research direction. Copper (Cu) is a relatively inexpensive metal. If introduced, it can not only reduce the material cost but also adjust the electronic structure. However, the existing preparation processes are complex, and it is difficult to simultaneously achieve uniform alloying of palladium, gold, and copper, controllable preparation of highly ordered mesoporous structures, and long-term stability of the material under the premise of low cost. Moreover, in terms of structural stability, trimetallic nanoparticles are prone to element segregation or lattice distortion during high-temperature or long-term catalytic reactions, resulting in attenuation of catalytic performance. How to achieve uniform composite of palladium, gold, and copper and precise regulation of mesoporous structures is still a technical difficulty. Therefore, there is an urgent need to develop a method for preparing palladium-gold-copper trimetallic nanoparticles. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles. The preparation method of the palladium-gold-copper trimetallic mesoporous nanoparticles is based on the "one-pot" strategy, and through the synchronous reduction of multi-metal precursors, the directional synthesis of a dandelion-like structure with three-dimensional pores (2-5 nm) is realized, which can break through the phase separation limitation of traditional multi-metal particles, and utilize the synergistic effect of palladium, gold and copper to significantly improve the active site and electron transport efficiency, thereby endowing the material with excellent performance.

[0006] The present invention is realized by adopting the following technical solutions: A method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles, comprising the following steps: 1) Prepare a precursor mixed solution containing potassium tetrachloropalladate (K2PdCl4), copper dichloride dihydrate (CuCl2•2H2O) and potassium tetrachloroaurate (KAuCl4); 2) Add poloxamer (F127) under magnetic stirring. After F127 is fully dispersed, add L-ascorbic acid (AA), and continue stirring for two hours at normal temperature and pressure; 3) Palladium-gold-copper trimetallic mesoporous nanoparticles (PdAuCu MNPs) are obtained after centrifugation and washing.

[0007] Further preferably: the solution concentrations of potassium tetrachloropalladate (K2PdCl4), copper dichloride dihydrate (CuCl2•2H2O) and potassium tetrachloroaurate (KAuCl4) are all 0.02 mol / L, and the solvent is ultrapure water.

[0008] Further preferably: the volume ratio of potassium tetrachloropalladate (K2PdCl4), copper dichloride dihydrate (CuCl2•2H2O) and potassium tetrachloroaurate (KAuCl4) in the precursor mixed solution is 1:1:2.

[0009] Further preferably: the rotation speed of the magnetic stirring is 600-800 r / min, the mass concentration of F127 is 0.5%-1.5%, and the concentration of AA is 0.4 mol / L. The addition amount of F127 is 0.02-0.06 g of F127 added to every 4 mL of the precursor mixed solution; the addition amount of L-ascorbic acid is 0.4 mL of L-ascorbic acid added to every 4 mL of the precursor mixed solution.

[0010] Further preferred: the centrifugation speed is 12,000 r / min; the number of washing times is 3 - 5 times. The first time is washed with ethanol, and the rest are washed with ultrapure water. Specifically, the colloidal solution obtained in step 2) is centrifuged at 12,000 r / min for 10 minutes, the supernatant is removed, 5 mL of ethanol is added to the obtained solid under ultrasound, and after redispersion, it is centrifuged at 12,000 r / min for 10 minutes; the supernatant is removed, and the obtained solid is centrifuged and washed 3 times with ultrapure water. The product after centrifugation is redispersed in ultrapure water to obtain a liquid sample. The liquid sample is freeze-dried to obtain a solid sample.

[0011] The technical solution provided by the present invention has at least the following beneficial effects compared with the prior art: 1) The preparation method of the palladium-gold-copper trimetallic mesoporous nanoparticles has the advantages of simple and efficient operation, mild preparation conditions, and environmental friendliness. It is an efficient and controllable trimetal synthesis technology, breaking through the technical contradiction between multi-component compatibility, structural stability, and large-scale preparation.

[0012] 2) The preparation method of the palladium-gold-copper trimetallic mesoporous nanoparticles can synchronously reduce the trimetal precursor in one pot. The prepared PdAuCu MNPs have good dispersion, a large surface active area, high catalytic activity, and high stability, and do not aggregate within one year at 4 °C, solving the problems of small surface active area, low catalytic activity, and high preparation cost of palladium-gold bimetallic nanoparticles.

[0013] 3) The PdAuCu MNPs prepared by the preparation method of the palladium-gold-copper trimetallic mesoporous nanoparticles have pore channels of 2 - 5 nm. The mesoporous structure not only exposes a large number of active sites but also can significantly improve the mass transfer and charge transfer efficiency. The electronic synergistic effect between multiple metals can improve the reaction activity and anti-poisoning ability, and can be applied in fields such as drug delivery and catalysis. Description of the Drawings

[0014] Figure 1 It is a low-resolution transmission electron microscope (TEM) image (inserted particle size statistical chart) of the PdAuCu MNPs prepared in Example 1; Figure 2 It is a high-resolution transmission electron microscope (TEM) image (inserted local area enlarged view) of the PdAuCu MNPs prepared in Example 1; Figure 3 It is Figure 2 The enlarged view of the local area in Figure 4 It is the wide-angle XRD pattern of the PdAuCu MNPs prepared in Example 1; Figure 5 It is Figure 4The spectrum with a diffraction angle of 36 - 43°; Figure 6 Full - spectrum scan of the X - ray photoelectron spectroscopy (XPS spectrum) of PdAuCu MNPs prepared in Example 1; Figure 7 High - resolution narrow - region scan spectrum of the Pd 3d orbital; Figure 8 High - resolution narrow - region scan spectrum of the Au 4f orbital; Figure 9 High - resolution narrow - region scan spectrum of the Cu 2p orbital; Figure 10 TEM image (inserted high - resolution image of the local area) of the palladium - copper bimetallic nanoparticles (PdCu NPs) prepared in Comparative Example 1; Figure 11 Low - resolution TEM image (inserted particle size statistical chart) of the palladium - gold bimetallic nanoparticles (PdAu NPs) prepared in Comparative Example 2; Figure 12 High - resolution TEM image (inserted enlarged image of the local area) of the palladium - gold bimetallic nanoparticles (PdAu NPs) prepared in Comparative Example 2; Figure 13 Cyclic voltammetry (CV) curves measured for PdAuCu MNPs, PdCu NPs, and PdAu NPs prepared in Example 1 and Comparative Examples 1 and 2 in 1 mol / L potassium hydroxide solution; Figure 14 For the Figure 13 Electrochemically active surface area (ECSA) diagram calculated; Figure 15 CV diagrams measured for PdAuCu MNPs, PdCu NPs, and PdAu NPs prepared in Example 1 and Comparative Examples 1 and 2 in a mixed solution of 1 mol / L KOH and 1 mol / L ethanol (C2H5OH); Figure 16 For the Figure 15 Mass activity (MA) and specific activity (SA) diagrams calculated; Figure 17 Chronoamperometry (CA) curves measured for PdAuCu MNPs, PdCu NPs, and PdAu NPs prepared in Example 1 and Comparative Examples 1 and 2 in a mixed solution of 1 mol / L KOH and 1 mol / L C2H5OH; Figure 18 For the Figure 16 MA diagram calculated after 3600 s in Figure 19TEM images and elemental mapping images (cyan signal for Pd, yellow signal for Au, and red signal for Cu) of the palladium-gold-copper trimetallic nanoparticles (PdAuCu NFs) prepared in Comparative Example 3; Figure 20 TEM image of the nanoparticles prepared in Comparative Example 4. Detailed implementation manners

[0015] The technical solutions in the invention will be clearly and completely described below in conjunction with the embodiments. The described embodiments are only a part of the invention, rather than all of the embodiments. Example 1

[0016] A preparation method of palladium-gold-copper trimetallic mesoporous nanoparticles, comprising the following steps: Prepare 0.02 mol / L solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4, and 0.4 mol / L AA solution for later use. Take a clean beaker (10 mL), place a magnetic stir bar, and sequentially add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 600 r / min. After stirring evenly, add 0.04 g of F127 (F127 mass concentration is 1.0%). After F127 is fully dispersed, add 0.4 mL of AA and continue to stir for two hours at normal temperature and pressure. Centrifuge the obtained colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL of ethanol to the obtained solid under ultrasound, redisperse it, and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water 3 times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample. The liquid sample can be freeze-dried to obtain a solid sample.

[0017] Observed the liquid sample under a transmission electron microscope. At low resolution, uniformly sized and well-dispersed nanoparticles can be seen, as Figure 1 shown. After particle size statistics, its particle size is 44±1 nm ( Figure 1 inset); at high resolution, the nanoparticles are in a dandelion shape, as Figure 2 shown. After measurement, analysis, and statistics, its pore size is 2-5 nm, Figure 3 and the pore size shown is 2.1 nm. The lattice of the nanoparticles is 2.27 Å ( Figure 2 inset), which is between Cu (2.08 Å), Pd (2.24 Å), and Au (2.36 Å), and is the (111) crystal plane of the palladium-gold-copper trimetallic alloy, indicating that PdAuCu MNPs are trimetallic alloy nanostructures.

[0018] The prepared solid sample was characterized by XRD, and the results are as Figure 4 shown. There are five characteristic peaks in the XRD pattern, which are the (111), (200), (220), (311), and (222) crystal planes of the face-centered cubic structure. Among them, the peak positions of the most obvious (111) and (200) crystal planes are located at 38.29 ° and 44.42 ° respectively. Compared with the Pd(111) standard crystal plane (PDF#46-1043), Au(111) standard crystal plane (PDF#89-3697), and Cu(111) standard crystal plane (PDF#04-083), the (111) crystal plane of PdAuCu MNPs has shifted to a higher angle, as Figure 5 shown, indicating the formation of the PdAuCu MNPs alloy structure.

[0019] The prepared solid sample was characterized by XPS, and the results are as Figure 6 shown. Obvious Au, Pd, and Cu signals appear at 83, 335, and 933 eV in the figure, indicating that PdAuCu MNPs is an alloy structure. The high-resolution XPS Pd 3d spectrum ( Figure 7 ) is split into two groups of peaks, which are Pd 3d 5 / 2 and Pd 3d 3 / 2 . The peak fitting is divided into two valence states of Pd 0 and Pd 2+ . Similarly, Cu 2p is also split into Cu 2p 3 / 2 and Cu 2p 1 / 2 ( Figure 9 ), and the peak fitting is divided into two valence states of Cu 0 and Cu 2+ . Au 4f ( Figure 8 ) is split into Au 4f 7 / 2 and Au4f 5 / 2 , attributed to Au 0 . The above results further prove that PdAuCu MNPs is a three-metal alloy structure. Example 2

[0020] A preparation method of palladium-gold-copper trimetallic mesoporous nanoparticles, comprising the following steps: Prepare 0.02 mol / L solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4, as well as a 0.4 mol / L AA solution for later use. Take a clean beaker (10 mL), place a magnetic stir bar in it, and successively add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 600 r / min. After stirring evenly, add 0.06 g of F127 (the mass concentration of F127 is 1.5%). After F127 is fully dispersed, add 0.4 mL of AA and continue to stir for two hours at normal temperature and pressure. Centrifuge the resulting colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL of ethanol to the obtained solid under ultrasonic treatment, redisperse it, and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water three times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample. The liquid sample can be freeze-dried to obtain a solid sample.

[0021] The characterization results and performance test results are basically the same as those in Example 1. Example 3

[0022] A preparation method of palladium-gold-copper trimetallic mesoporous nanoparticles includes the following steps: Prepare 0.02 mol / L solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4, as well as a 0.4 mol / L AA solution for later use. Take a clean beaker (10 mL), place a magnetic stir bar in it, and successively add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 600 r / min. After stirring evenly, add 0.02 g of F127 (the mass concentration of F127 is 0.5%). After F127 is fully dispersed, add 0.4 mL of AA and continue to stir for two hours at normal temperature and pressure. Centrifuge the resulting colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL of ethanol to the obtained solid under ultrasonic treatment, redisperse it, and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water three times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample. The liquid sample can be freeze-dried to obtain a solid sample.

[0023] The characterization results and performance test results are basically the same as those in Example 1. Example 4

[0024] A preparation method of palladium-gold-copper trimetallic mesoporous nanoparticles includes the following steps: Prepare 0.02 mol / L solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4, as well as a 0.4 mol / L AA solution for later use. Take a clean beaker (10 mL), place a magnetic stir bar in it, and successively add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 700 r / min. After stirring evenly, add 0.04 g of F127 (the mass concentration of F127 is 1.0%). After F127 is fully dispersed, add 0.4 mL of AA and continue stirring for two hours at normal temperature and pressure. Centrifuge the resulting colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL of ethanol to the obtained solid under ultrasonic treatment, redisperse it, and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water three times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample. The liquid sample can be freeze-dried to obtain a solid sample.

[0025] The characterization results and performance test results are basically the same as those in Example 1. Example 5

[0026] A preparation method of palladium-gold-copper trimetallic mesoporous nanoparticles, comprising the following steps: Prepare 0.02 mol / L solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4, as well as a 0.4 mol / L AA solution for later use. Take a clean beaker (10 mL), place a magnetic stir bar in it, and successively add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 800 r / min. After stirring evenly, add 0.04 g of F127 (the mass concentration of F127 is 1.0%). After F127 is fully dispersed, add 0.4 mL of AA and continue stirring for two hours at normal temperature and pressure. Centrifuge the resulting colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL of ethanol to the obtained solid under ultrasonic treatment, redisperse it, and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water three times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample. The liquid sample can be freeze-dried to obtain a solid sample.

[0027] The characterization results and performance test results are basically the same as those in Example 1.

[0028] Comparative Example 1 Prepare 0.02 mol / L K2PdCl4 and CuCl2•2H2O solutions respectively, as well as 0.4 mol / L AA solution for standby. Take a clean beaker (10 mL), put in a magnetic stir bar, and successively add 1 mL K2PdCl4, 1 mL CuCl2•2H2O, and 2 mL ultrapure water under magnetic stirring at 600 r / min. After stirring evenly, add 0.04 g F127 (F127 mass concentration is 1.0%). After F127 is fully dispersed, add 0.4 mL AA, and continue to stir for two hours at normal temperature and pressure. Centrifuge the obtained colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL ethanol to the obtained solid under ultrasonic treatment, redisperse it and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water 3 times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample. The liquid sample can be freeze-dried to obtain a solid sample.

[0029] When the prepared sample was observed under a transmission electron microscope, it was found that without the gold precursor solution, the gold nanoskeleton could not be provided, so the palladium-copper bimetallic nanoparticles did not form dandelion-like nanoparticles with a mesoporous structure, as Figure 10 shown.

[0030] Comparative Example 2 Prepare 0.02 mol / L K2PdCl4 and KAuCl4 solutions respectively, as well as 0.4 mol / L AA solution for standby. Take a clean beaker (10 mL), put in a magnetic stir bar, and successively add 1 mL K2PdCl4, 2 mL KAuCl4, and 1 mL ultrapure water under magnetic stirring at 600 r / min. After stirring evenly, add 0.04 g F127 (F127 mass concentration is 1.0%). After F127 is fully dispersed, add 0.4 mL AA, and continue to stir for two hours at normal temperature and pressure. Centrifuge the obtained colloidal solution at 12000 r / min for 10 minutes, remove the supernatant, add 5 mL ethanol to the obtained solid under ultrasonic treatment, redisperse it and then centrifuge at 12000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water 3 times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample.

[0031] When the prepared sample was observed under a transmission electron microscope, it was found that the palladium-gold bimetallic nanoparticles were dandelion-like nanoparticles with a mesoporous structure, as Figure 11 and Figure 12 shown.

[0032] The ethanol oxidation (EOR) catalytic performance of the prepared palladium-gold bimetallic nanoparticles was compared with that of palladium-gold-copper trimetallic mesoporous nanoparticles and palladium-copper bimetallic nanoparticles. From Figure 13 and Figure 14 it can be seen that the PdAuCu MNPs have the largest surface active area; from Figure 15 and Figure 16 it can be seen that the catalytic activity is the highest; from Figure 17 and Figure 18 it can be seen that the catalytic stability is the best. Thus, compared with PdAu NPs, the addition of Cu to PdAuCu MNPs changes the surface electronic structure of the trimetallic nanoparticles, exposing more active sites and endowing the trimetallic catalyst with better catalytic activity and stability.

[0033] Comparative Example 3 Solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4 with a concentration of 0.02 mol / L and an AA solution with a concentration of 0.4 mol / L were prepared separately for standby. Take a clean beaker (10 mL), place a magnetic stir bar in it, and sequentially add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 600 r / min. After stirring evenly, add 0.04 g of polyvinylpyrrolidone (PVP mass concentration is 1.0%). After PVP is fully dispersed, add 0.4 mL of AA and continue stirring for two hours at normal temperature and pressure. The obtained colloidal solution was centrifuged at 12000 r / min for 10 minutes, the supernatant was removed, and the obtained solid was added with 5 mL of ethanol under ultrasonic treatment, redispersed, and then centrifuged at 12000 r / min for 10 minutes; the supernatant was removed, and the obtained solid was centrifuged and washed 3 times with ultrapure water. The centrifuged product was redispersed in ultrapure water to obtain a liquid sample.

[0034] The prepared sample was observed under a transmission electron microscope, and it can be seen that the palladium-gold-copper trimetallic nanoparticles (PdAuCu NFs) did not form a mesoporous structure, as shown in Figure 19 shown.

[0035] Comparative Example 4 Prepare 0.02 mol / L solutions of K2PdCl4, CuCl2•2H2O, and KAuCl4, as well as a 0.4 mol / L AA solution for later use. Take a clean beaker (10 mL), place a magnetic stir bar in it, and sequentially add 1 mL of K2PdCl4, 1 mL of CuCl2•2H2O, and 2 mL of KAuCl4 under magnetic stirring at 600 r / min. After stirring evenly, add 0.4 mL of AA and continue stirring for two hours at normal temperature and pressure. Centrifuge the resulting colloidal solution at 12,000 r / min for 10 minutes, remove the supernatant, add 5 mL of ethanol to the obtained solid under ultrasonic treatment, redisperse it, and then centrifuge at 12,000 r / min for 10 minutes; remove the supernatant, and continue to centrifuge and wash the obtained solid with ultrapure water three times. The centrifuged product is redispersed in ultrapure water to obtain a liquid sample.

[0036] Observe the prepared sample under a transmission electron microscope. It can be seen that dandelion-shaped palladium-gold-copper nanoparticles with mesopores are not formed, as Figure 20 shown.

[0037] The above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Any changes, modifications, additions, or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing palladium, gold and copper tri-metal mesoporous nanoparticles, characterized in that: The steps include: 1) preparing a precursor mixed solution containing potassium tetrachloropalladate, cupric chloride dihydrate and potassium chloroaurate; 2) Add poloxamer F127 under magnetic stirring, add L-ascorbic acid after poloxamer F127 is fully dispersed, and continue stirring at room temperature and pressure for two hours; 3) After centrifugation and washing, palladium, gold, and copper tri-metal mesoporous nanoparticles are obtained.

2. The method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles according to claim 1, characterized in that: The volume ratio of potassium tetrachloropalladate, cupric chloride dihydrate and potassium chloroaurate in the precursor mixed solution is 1:1:

2.

3. The method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles according to claim 1 or 2, characterized in that: The solution concentrations of potassium tetrachloropalladate, cupric chloride dihydrate and potassium chloroaurate are all 0.02 mol / L.

4. The method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles according to claim 1, characterized in that: The magnetic stirring speed is 600-800 r / min.

5. The method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles according to claim 1, characterized in that: The mass concentration of the poloxamer F127 is 0.5%-1.5%, and the concentration of L-ascorbic acid is 0.4 mol / L.

6. The method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles according to claim 1 or 5, characterized in that: The amount of poloxamer F127 added is 0.02-0.06 g of poloxamer F127 per 4 mL of the precursor mixed solution; the amount of L-ascorbic acid added is 0.4 mL of L-ascorbic acid per 4 mL of the precursor mixed solution.

7. The method for preparing palladium-gold-copper trimetallic mesoporous nanoparticles according to claim 1, characterized in that: The washing times are 3-5 times, the first washing is done with ethanol, and the rest are done with ultrapure water.

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