Preparation method of modified palladium-copper alloy nanoparticles

Abstract

The application provides a preparation method of modified palladium-copper alloy nanoparticles, which comprises the following steps: preparing palladium-copper alloy nanoparticles by using a palladium precursor and a copper precursor as raw materials, and then treating the palladium-copper alloy nanoparticles by high-intensity focused ultrasound to obtain modified palladium-copper alloy nanoparticles. The application also provides modified palladium-copper alloy nanoparticles prepared by using the preparation method. The modified palladium-copper alloy nanoparticles have a smaller particle size than the unmodified palladium-copper alloy nanoparticles, and the modified palladium-copper alloy nanoparticles have higher catalytic degradation activity in degrading p-nitrophenol. The modified palladium-copper alloy nanoparticles have better dye degradation activity in degrading methyl orange.

Description

Technical Field

[0001] This invention relates to the field of alloy nanoparticle technology, specifically to a method for preparing modified palladium-copper alloy nanoparticles. Background Technology

[0002] Alloy nanoparticles have attracted widespread attention due to their unique catalytic, electronic, and optical properties. Furthermore, they have various applications in different fields, such as platinum-based catalysts in fuel cells, redox reactions, hydrogen evolution reactions, and biocompatible integration. However, due to the scarcity and high cost of platinum itself, replacing platinum with abundant transition metals has recently emerged as one of the most effective strategies for optimizing platinum usage. For example, palladium-based alloys and iron-based alloys offer good overall performance and wide applications, primarily in inductors, redox reactions, ion deposition, and spray welding processes. However, iron-based alloys are difficult to store and unstable, easily oxidizing at room temperature. When examining the characterization of bimetallic alloy nanoparticles, the biggest difference lies in the composition of each metal. Due to the need for additional functionalization, many alloys (such as iron-gold, iron-platinum, platinum, palladium-platinum bimetallic alloy nanoparticles, etc.) are modified or reconstructed when forming hydrophilic components. Each step in the process conveys further methods, and the alloys are used to catalyze and degrade phenomena to detect environmental and metal ions. As a fundamental principle for preparing hydrophilic dye catalysts in water-soluble media, the hydrophilic state illustrates significant possibilities and is considered one of the important factors in alloying and surface structure.

[0003] As a novel structure, it expands the scope of practical applications while leveraging the performance of hydrophilic alloys for internal electron transfer and synergistic functions. Of course, a non-hydrophilic interface cannot maintain the normal germination of water-soluble reactions; it prevents the alloy from contacting the target molecule and exhibiting internal cross-linking between the catalyst and the target molecule. The lack of any enhancement in catalytic performance implies the necessity of a hydrophilic state, with further enhancements categorized as superhydrophilic states, signifying high stability (in solution) and monodispersity in colloidal solutions. Generally, catalytic performance depends primarily on the size distribution, surface modification, composition, and crystallization parameters of the bimetallic alloy. In palladium-based bimetallic alloys, it can both maintain the functional properties of each component and provide synergistic effects through synergistic interactions, thus producing important properties. Alloying procedures can provide unique strategies for customizing the geometry and electronic structure of the catalyst surface. Palladium alloys are typical members of the original palladium-based composite materials and can be found in various catalysis, environmental fields, or natural or industrial engineering applications such as polymer synthesis and material surface modification. Compared to other existing alloys, palladium-based alloys are easy to produce, widely used, and inexpensive, making them a good choice for alloy preparation. Palladium-based alloy nanoparticle catalysts have also shown promising redox activity and provide a cost-effective alternative to previous metal candidates.

[0004] According to the synthetic method, palladium-based alloys were well prepared in a solvothermal process, and the resulting alloys exhibited good size distribution and monodispersity in organic colloidal solutions. To prove their effectiveness as catalysts or biocompatible metalloenzymes, bimetallic nanoparticles should be modified in further processing, such as ligand exchange in commercial toner integration and surface structure reconstruction. However, due to the complex processes involved in the improved strategies, hydrophilic palladium-copper alloy nanoparticles were ultimately obtained, but their dispersion and stability in aqueous media were poor, even exhibiting "superhydrophilic" properties. For example, in biocatalysts, hydrophobic surfaces composed of long-chain alkanes can be used for ligand exchange strategies to facilitate further work. "Secondary" modifications, such as C, SiO2, and PEG, are often used. This can yield new surface modifications, making the alloy nanoparticles more stable, but to some extent reducing their catalytic activity. Furthermore, this means that smaller catalytic alloys should have higher catalytic activity, but they may not be recognized during modification, and the added molecules may become obstacles in the reaction, ultimately leading to a decrease in the reaction rate. It seems that the size of the alloy is a crucial factor determining its performance. Of course, maintaining the diameter of nanoparticles stably without any further modification is required, as it can greatly increase the exposed sites and improve catalytic performance.

[0005] Based on the above reasonable requirements, a palladium-copper alloy is needed that not only has superhydrophilic properties, but also maintains multiple functions such as catalytic performance and degradation performance in dye catalytic reactions. Summary of the Invention

[0006] I. Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a method for preparing modified palladium-copper alloy nanoparticles. The prepared palladium-copper alloy nanoparticles retain superhydrophilicity while improving catalytic performance and degradation activity.

[0008] II. Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A method for preparing modified palladium-copper alloy nanoparticles, the key of which is: using palladium precursor and copper precursor as raw materials to prepare palladium-copper alloy nanoparticles in a one-pot method, and then subjecting the palladium-copper alloy nanoparticles to high-intensity focused ultrasound treatment to obtain modified palladium-copper alloy nanoparticles.

[0011] Optionally, the pressure in the high-intensity focused ultrasound treatment is 7-10 MPa, and the power is 3000-4000 W.

[0012] Optionally, the preparation method of the palladium-copper alloy nanoparticles is as follows: add palladium precursor and copper precursor to solvent, add stabilizer, adjust pH to 10.5-11.5 after ultrasonic treatment, add reducing agent solution dropwise until the solution color changes; continue the reaction for 3-3.5 hours, and finally freeze dry for later use.

[0013] Optionally, the palladium precursor is palladium hexafluoroacetylacetone;

[0014] And / or the copper precursor is copper acetylacetonate.

[0015] Optionally, the molar ratio of the palladium precursor to the copper precursor is (1-7):(1-7).

[0016] Optionally, the amount of the palladium precursor is 0.01–0.02 mmol;

[0017] And / or the amount of the copper precursor is 0.01 to 0.02 mmol.

[0018] Optionally, the molar ratio of the palladium precursor to the copper precursor is (1:1) or (1:2) or (1:3) or (1:5) or (1:7) or (2:1) or (3:1) or (5:1) or (7:1).

[0019] Optionally, the molar ratio of the palladium precursor to the copper precursor is 7:1.

[0020] Optionally, the stabilizer is glutathione, and the amount added is 3 times the amount of the palladium precursor.

[0021] And / or the reducing agent is a sodium borohydride solution, added in an amount equal to 1 times the amount of the palladium precursor.

[0022] Optionally, the solvent is a mixture of deionized water and anhydrous ethanol in equal volume ratio.

[0023] The present invention also provides modified palladium-copper alloy nanoparticles prepared by the preparation method of modified palladium-copper alloy nanoparticles described in any of the above examples.

[0024] III. Beneficial Effects

[0025] This invention discloses a method for preparing modified palladium-copper alloy nanoparticles. The modified palladium-copper alloy nanoparticles have a smaller particle size than the unmodified ones. The modified palladium-copper alloy nanoparticles exhibit high catalytic degradation activity when degrading p-nitrophenol. The modified palladium-copper alloy nanoparticles also exhibit good dye degradation activity when degrading methyl orange. Attached Figure Description

[0026] Figure 1This is a lens image of the modified palladium-copper alloy nanoparticles Pd7Cu1 in Example 1;

[0027] Figure 2 This is a UV-Vis spectral analysis curve of the modified palladium-copper alloy nanoparticles Pd7Cu1 in Example 1 on the degradation of methyl orange.

[0028] Figure 3 Logarithmic plots showing the reduction of p-nitrophenol by nine different modified palladium-copper alloy nanoparticles;

[0029] Figure 4 UV-Vis spectra of nine modified palladium-copper alloy nanoparticles degrading methyl orange.

[0030] Figure 5 Comparison of the particle size changes of palladium-copper alloy nanoparticles Pd7Cu1 before and after high-intensity focused ultrasound treatment (a is before high-intensity focused ultrasound treatment, b is after high-intensity focused ultrasound treatment).

[0031] Figure 6 Lens images of palladium-copper alloy nanoparticles Pd7Cu1 before and after high-intensity focused ultrasound treatment (a is before high-intensity focused ultrasound treatment, b is after high-intensity focused ultrasound treatment).

[0032] Figure 7 The UV-Vis spectra of the degradation of methyl orange by palladium-copper alloy nanoparticles Pd7Cu1 before and after high-intensity focused ultrasound treatment are shown in the figure (a is before high-intensity focused ultrasound treatment, b is after high-intensity focused ultrasound treatment).

[0033] Figure 8 The images show the UV-Vis spectra of Pd7Cu1 palladium-copper alloy nanoparticles before and after high-intensity focused ultrasound (HIFU) treatment (a is before HIFU treatment, b is after HIFU treatment). Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise specified, all raw materials used in this invention can be obtained commercially, and the equipment used in this invention can be conventional equipment in the relevant field or refer to existing technology in the relevant field.

[0036] Example 1

[0037] This invention discloses a method for preparing modified palladium-copper alloy nanoparticles:

[0038] I. Palladium-copper alloy nanoparticles were prepared using a one-pot method:

[0039] 1. First, prepare nine 100mL beakers and add equal volumes of deionized water and anhydrous ethanol to them.

[0040] 2. The metal precursors palladium hexafluoroacetylacetone and copper acetylacetone were added to nine beakers in the following molar ratios: (1:1), (1:2), (1:3), (1:5), (1:7), (2:1), (3:1), (5:1), and (7:1).

[0041] 3. Weigh out 3 times the amount of glutathione as palladium hexafluoroacetylacetone and add them to the corresponding beakers. Place the beakers in an ultrasonic cleaner and sonicate for 5 minutes to allow the reactants to fully dissolve and react.

[0042] 4. Adjust the pH of the solution with sodium hydroxide solution to 11±0.5. The solution should be transparent.

[0043] 5. Weigh out one amount of sodium borohydride solution equal to the amount of palladium hexafluoroacetylacetone and dissolve it in 1 mL of deionized water. After complete dissolution, add the solution dropwise to the corresponding beakers until the solution color changes. Continue the reaction for 3-3.5 hours and collect the samples. This yields nine alloy nanoparticles with different proportions, denoted as Pd1Cu1, Pd1Cu2, Pd1Cu3, Pd1Cu5, Pd1Cu7, Pd2Cu1, Pd3Cu1, Pd5Cu1, and Pd7Cu1, respectively.

[0044] 6. Place the prepared alloy nanoparticle solution in a cuvette, freeze it in a -80℃ freezer, and then freeze-dry it to obtain a powder sample for later use.

[0045] 2. The nine types of palladium-copper alloy nanoparticles prepared were subjected to high-intensity focused ultrasound treatment at a pressure of 10 MPa and a power of 3000 W to obtain modified palladium-copper alloy nanoparticles.

[0046] III. Transmission spectroscopy and UV-Vis spectral analysis of methyl orange degradation using palladium-copper alloy nanoparticles (Pd7Cu1), lens image as shown below. Figure 1 As shown in the figure, the ultraviolet-visible spectral analysis curve is as follows: Figure 2 As shown in the figure. The results indicate that the particle size of palladium-copper alloy nanoparticles can reach less than 5 nm, and the reaction rate for degrading methyl orange can reach 20 s.

[0047] Example 2

[0048] This invention discloses a method for preparing modified palladium-copper alloy nanoparticles:

[0049] I. Palladium-copper alloy nanoparticles were prepared using a one-pot method:

[0050] 1. First, prepare nine 100mL beakers and add equal volumes of deionized water and anhydrous ethanol to them.

[0051] 2. The metal precursors palladium hexafluoroacetylacetone and copper acetylacetone were added to nine beakers in the following molar ratios: (1:1), (1:2), (1:3), (1:5), (1:7), (2:1), (3:1), (5:1), and (7:1).

[0052] 3. Weigh out 3 times the amount of glutathione as palladium hexafluoroacetylacetone and add them to the corresponding beakers. Place the beakers in an ultrasonic cleaner and sonicate for 5 minutes to allow the reactants to fully dissolve and react.

[0053] 4. Adjust the pH of the solution with sodium hydroxide solution to 11±0.5. The solution should be transparent.

[0054] 5. Weigh out one amount of sodium borohydride solution equal to the amount of palladium hexafluoroacetylacetone and dissolve it in 1 mL of deionized water. After complete dissolution, add the solution dropwise to the corresponding beakers until the solution color changes. Continue the reaction for 3-3.5 hours and collect the samples. This yields nine alloy nanoparticles with different proportions, denoted as Pd1Cu1, Pd1Cu2, Pd1Cu3, Pd1Cu5, Pd1Cu7, Pd2Cu1, Pd3Cu1, Pd5Cu1, and Pd7Cu1, respectively.

[0055] 6. Place the prepared alloy nanoparticle solution in a cuvette, freeze it in a -80℃ freezer, and then freeze-dry it to obtain a powder sample for later use.

[0056] 2. The nine types of palladium-copper alloy nanoparticles prepared were subjected to high-intensity focused ultrasound treatment with a pressure of 7 MPa and a power of 4000 W to obtain modified palladium-copper alloy nanoparticles.

[0057] Example 3

[0058] This invention discloses a method for preparing modified palladium-copper alloy nanoparticles:

[0059] I. Palladium-copper alloy nanoparticles were prepared using a one-pot method:

[0060] 1. First, prepare nine 100mL beakers and add equal volumes of deionized water and anhydrous ethanol to them.

[0061] 2. The metal precursors palladium hexafluoroacetylacetone and copper acetylacetone were added to nine beakers in the following molar ratios: (1:1), (1:2), (1:3), (1:5), (1:7), (2:1), (3:1), (5:1), and (7:1).

[0062] 3. Weigh out 3 times the amount of glutathione as palladium hexafluoroacetylacetone and add them to the corresponding beakers. Place the beakers in an ultrasonic cleaner and sonicate for 5 minutes to allow the reactants to fully dissolve and react.

[0063] 4. Adjust the pH of the solution with sodium hydroxide solution to 11±0.5. The solution should be transparent.

[0064] 5. Weigh out one amount of sodium borohydride solution equal to the amount of palladium hexafluoroacetylacetone and dissolve it in 1 mL of deionized water. After complete dissolution, add the solution dropwise to the corresponding beakers until the solution color changes. Continue the reaction for 3-3.5 hours and collect the samples. This yields nine alloy nanoparticles with different proportions, denoted as Pd1Cu1, Pd1Cu2, Pd1Cu3, Pd1Cu5, Pd1Cu7, Pd2Cu1, Pd3Cu1, Pd5Cu1, and Pd7Cu1, respectively.

[0065] 6. Place the prepared alloy nanoparticle solution in a cuvette, freeze it in a -80℃ freezer, and then freeze-dry it to obtain a powder sample for later use.

[0066] 2. The nine types of palladium-copper alloy nanoparticles prepared were subjected to high-intensity focused ultrasound treatment at a pressure of 10 MPa and a power of 4000 W to obtain modified palladium-copper alloy nanoparticles.

[0067] Example 4: Detection of catalytic activity in the degradation of p-nitrophenol

[0068] Catalytic activity experiments were conducted on p-nitrophenol using modified palladium-copper alloy nanoparticles prepared in different proportions as described in Example 3. The dye degradation reaction of the nanoparticles followed a first-order kinetic equation: In(A t / A0)=-kt, where A t A0 represents the absorbance of the solution at t=t and t=0, respectively, which is also equivalent to t=t(C t The concentration of the solution at t = 0 (C0) is given by ), and k is the apparent rate constant. A larger k value indicates higher catalytic activity of the sample. Results are as follows: Figure 3 As shown in Table 1, from Figure 3 As shown in Table 1, a higher palladium content corresponds to a larger k value, resulting in higher catalytic activity and a faster reaction rate. Therefore, from the perspective of catalytic activity, the optimal molar ratio of palladium precursor to copper precursor in the preparation of palladium-copper alloy nanoparticles is 7:1.

[0069] Table 1. Effect of different proportions of modified palladium-copper alloy nanoparticles on the reaction rate.

[0070] Sample Name Restoration time (s) <![CDATA[Apparent rate constant (k app , 10 -3 s -1 )]]> <![CDATA[Pd1Cu1]]> 600 4.44 <![CDATA[Pd1Cu2]]> 360 7.4 <![CDATA[Pd1Cu3]]> 330 6.92 <![CDATA[Pd1Cu5]]> 240 13.6 <![CDATA[Pd1Cu7]]> 210 15.2 <![CDATA[Pd2Cu1]]> 300 9.9 <![CDATA[Pd3Cu1]]> 270 8.7 <![CDATA[Pd5Cu1]]> 120 23 <![CDATA[Pd7Cu1]]> 60 46

[0071] Example 5: Detection of dye degradation activity for methyl orange dye

[0072] The modified palladium-copper alloy nanoparticles prepared in Example 3 with different proportions were used to conduct fuel degradation activity experiments on methyl orange. The UV-Vis spectra of the dye degradation of the modified palladium-copper alloy nanoparticles synthesized with nine different precursor ratios were analyzed. The results are as follows: Figure 4 As shown in the figure, the higher the palladium content in the alloy, the shorter the degradation reaction time of methyl orange and the faster the dye degradation rate, which indicates that the dye degradation activity is better. Therefore, from the perspective of dye degradation activity, the preferred molar ratio of palladium precursor to copper precursor in the preparation of palladium-copper alloy nanoparticles is 7:1.

[0073] Example 6: Detection of particle size change of palladium-copper alloy nanoparticles before and after modification

[0074] I. Particle size acoustic wave detection was performed on the unmodified palladium-copper alloy nanoparticles Pd7Cu1 and the modified palladium-copper alloy nanoparticles Pd7Cu1 in Example 3. The results are as follows: Figure 5 As shown.

[0075] II. Simultaneously, transmission electron microscopy (TEM) was performed on both the unmodified and modified palladium-copper alloy nanoparticles (Pd7Cu1) from Example 3. Figure 6 As shown, and the UV-Vis spectral analysis of the degradation of methyl orange dye, as shown. Figure 7 As shown.

[0076] III. Results:

[0077] 1. Through Figure 5 Figures a and b in the text Figure 6 Figures a and b show that the particle size of the palladium-copper alloy nanoparticles Pd7Cu1 treated with high-intensity focused ultrasound decreased from 10.4±0.6 nm to 3.7±0.1 nm, indicating a significant reduction in particle size.

[0078] 2. Through Figure 7 Figures a and b show that the degradation time of methyl orange dye by palladium-copper alloy nanoparticles treated with high-intensity focused ultrasound is reduced, indicating that the dye degradation activity is greatly improved. The smaller particle size of the palladium-copper alloy nanoparticles provides an excitation reaction for electron transfer. Due to the presence of more active sites, the higher dye degradation performance is obtained. This indicates that the reduction in particle size of the alloy nanoparticles is the direct reason for the improved dye degradation activity.

[0079] Example 7: Changes in the hydrophilicity of palladium-copper alloy nanoparticles before and after modification

[0080] Traditionally, palladium-copper bimetallic nanoparticles are considered one of the representative particles in palladium bimetallic alloys with multiple properties. This can be attributed to the fact that copper ions (cations) can switch between different valence states (+1, +2), where a monovalent copper ion can lose an electron to become a divalent copper ion, and it can gain an electron to become a monovalent copper ion to control electroreduction and peroxide formation. A hydrophilic state must be maintained for the target reaction to occur properly.

[0081] Therefore, UV-Vis spectroscopy analysis was performed on the unmodified palladium-copper alloy nanoparticles Pd7Cu1 and the modified palladium-copper alloy nanoparticles Pd7Cu1 in Example 3, and the results are as follows. Figure 8 As shown, this demonstrates that regardless of whether or not the alloy nanoparticles have undergone high-intensity focused ultrasound treatment, they remain relatively stable and maintain a hydrophilic state.

[0082] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0083] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing modified palladium-copper alloy nanoparticles, characterized in that: Palladium-copper alloy nanoparticles were prepared using palladium and copper precursors as raw materials, and then the palladium-copper alloy nanoparticles were subjected to high-intensity focused ultrasound treatment to obtain modified palladium-copper alloy nanoparticles. The molar ratio of the palladium precursor to the copper precursor is (2~7):1; The pressure in the high-intensity focused ultrasound treatment is 7~10MPa, and the power is 3000~4000W; The specific preparation method of the palladium-copper alloy nanoparticles is as follows: the palladium precursor and the copper precursor are added to a solvent, a stabilizer is added, the pH is adjusted to 10.5-11.5 after ultrasonic treatment, and sodium borohydride solution is added dropwise until the solution color changes; the reaction is continued for 3-3.5 hours, and finally the mixture is freeze-dried and stored for later use.

2. The method for preparing modified palladium-copper alloy nanoparticles according to claim 1, characterized in that: The palladium precursor is palladium hexafluoroacetylacetone; And / or the copper precursor is copper acetylacetonate.

3. The method for preparing modified palladium-copper alloy nanoparticles according to claim 1, characterized in that: The amount of the palladium precursor is 0.01~0.02 mmol; And / or the amount of the copper precursor is 0.01~0.02 mmol.

4. The method for preparing modified palladium-copper alloy nanoparticles according to claim 3, characterized in that: The molar ratio of the palladium precursor to the copper precursor is (2:1), (3:1), (5:1), or (7:1).

5. The method for preparing modified palladium-copper alloy nanoparticles according to claim 4, characterized in that: The molar ratio of the palladium precursor to the copper precursor is 7:

1.

6. The method for preparing modified palladium-copper alloy nanoparticles according to claim 1, characterized in that: The stabilizer is glutathione, and the amount added is three times the amount of the palladium precursor.

7. The method for preparing modified palladium-copper alloy nanoparticles according to claim 1, characterized in that: The solvent is a mixture of deionized water and anhydrous ethanol in equal volume ratio.

8. A modified palladium-copper alloy nanoparticle prepared by the preparation method according to any one of claims 1 to 7.

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