A method for preparing crystalline PdCN@amorphous PdP core-shell nanoparticles
By preparing crystalline PdCN@amorphous PdP core-shell nanoparticles, the problem of difficult balance of platinum group metal heterostructures was solved, the stability of the catalyst and the active sites were improved, and the efficiency of the electrochemical reaction was improved.
Patent Information
- Application Number
- CN202411886896.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-10-14
- Estimated Expiration
- 2044-12-20
AI Technical Summary
Existing technologies have difficulty balancing the transition between crystalline and amorphous heterostructures of platinum group metals, leading to challenges in constructing heterostructured catalysts. In particular, the structural flexibility and stability of amorphous phase materials are not fully utilized during electrochemical catalysis.
By doping carbon, nitrogen, and phosphorus with non-metallic elements, crystalline PdCN@amorphous PdP core-shell nanoparticles with uniform size were prepared using simple laboratory equipment and commercially available reagents.
Crystalline PdCN@amorphous PdP core-shell nanoparticles of uniform size were successfully prepared, which improved the stability and catalytic performance of the catalyst, provided more active sites, and enhanced the efficiency of the electrochemical reaction.
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Figure CN119683574B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of nanomaterial synthesis and application, and particularly relates to a preparation method of crystalline PdCN@amorphous PdP core-shell nanoparticles. BACKGROUND
[0002] Since the heterostructure was first proposed in the application of wide-gap semiconductor emitters, it has attracted extensive attention in many energy fields due to its unique physical and chemical properties. In particular, heterostructure nanomaterials exhibit unique microstructures due to the formation of heterojunctions inside, which can fully absorb the advantages of individual components and discard their inherent shortcomings, thereby producing strong synergistic effects and significantly improving the performance of various electrochemical technologies, such as oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), lithium-ion batteries, and sodium-ion batteries. At the same time, in the field of electrochemistry, crystalline materials based on platinum group metals are generally considered to be the most effective catalysts. Therefore, the synthesis of heterostructure materials based on platinum group metals has attracted much attention.
[0003] At present, most researches focus on heterostructures composed of two crystalline phases. However, in recent years, it has been reported that amorphous phase materials exhibit extraordinary structural flexibility and better corrosion resistance in electrochemical catalytic processes compared to crystalline phases. This is mainly attributed to the following three aspects: first, the charge transfer in the heterojunction promotes the redistribution of electrons, thereby adjusting the band structure of the components; second, the crystal-amorphous hybrid structure can expose more vacancies on the surface, providing sufficient active sites for catalytic reactions; third, the amorphous shell structure can effectively delay the dissolution or precipitation process of reactants, thereby enhancing the stability of the catalyst. In addition, the core-shell structure has adjustable catalytic performance, which can be controlled by changing the element composition and morphology, thereby optimizing the synergistic effect between different components and the combination of various properties. Therefore, designing crystalline@amorphous core-shell heterojunction materials based on platinum group metals has become a hot research topic in the field of electrochemistry. However, due to the difficulty in balancing the transition between crystalline-amorphous heterostructures in platinum group metals, it is still challenging to construct such heterostructures. In view of this, exploring the synthesis of crystalline@amorphous core-shell heterojunction materials based on platinum group metals has important academic significance and application value. Therefore, the present application proposes a preparation method of crystalline PdCN@amorphous PdP core-shell nanoparticles. SUMMARY
[0004] The purpose of the present application is to provide a preparation method of crystalline PdCN@amorphous PdP core-shell nanoparticles, which aims to solve the problems raised in the background art.
[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:
[0006] A method for preparing crystalline PdCN@amorphous PdP core-shell nanoparticles comprises the following steps:
[0007] Step 1. Preparing cubic Pd nanoparticles: Polyvinyl pyrrolidone, L-ascorbic acid, and potassium bromide are added to deionized water to form a mixed solution. After preheating an oil bath, a sodium chloropalladate solution is rapidly injected into the mixed solution, which is then transferred to an oil bath. After the reaction is complete, the temperature is lowered to room temperature. The resulting solution is centrifuged and washed with deionized water, ethanol, and acetone to obtain cubic Pd nanoparticles, which are then dried for later use.
[0008] Step 2: Preparing cubic PdCN nanoparticles: dissolving cubic Pd nanoparticles in a dimethyl sulfoxide solution and transferring the solution to a reactor for reaction; centrifuging and washing the resulting solution with deionized water and ethanol to obtain cubic PdCN nanoparticles, which are then dried and stored;
[0009] Step 3: Preparation of crystalline PdCN@amorphous PdP core-shell nanoparticles: Mix cubic PdCN nanoparticles with oleylamine solution, add trioctylphosphine solution and heat; centrifuge and wash the resulting solution with ethanol and toluene to obtain crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0010] Furthermore, the specific process of step 1 is as follows:
[0011] 1.05 g of polyvinyl pyrrolidone, 0.6 g of L-ascorbic acid, and 6 g of potassium bromide were added to 80 mL of deionized water to form a mixed solution. The oil bath was preheated for 10 min until the temperature reached 85°C. 30 mL of a 0.065 mol / L sodium chloropalladate solution was quickly injected into the mixed solution. The mixed solution was then transferred to an oil bath and reacted at 85°C for 3 h. The temperature was then lowered to room temperature. The resulting solution was centrifuged and washed 2 to 3 times with deionized water, ethanol, and acetone to obtain cubic Pd nanoparticles, which were then dried for later use.
[0012] Furthermore, the specific process of step 2 is as follows:
[0013] 0.03 g of cubic Pd nanoparticles were weighed and dissolved in 60 mL of dimethyl sulfoxide solution, transferred to a reactor, and reacted at 180°C for 2 h. The resulting solution was centrifuged and washed 2 to 3 times with deionized water and ethanol to obtain cubic PdCN nanoparticles, which were then dried at 40°C for storage.
[0014] Furthermore, the specific process of step 3 is as follows:
[0015] The 21 mg cubic PdCN nanoparticles are weighed and mixed with 77 mL of oleylamine solution, 7 mL of trioctylphosphine solution is added, and the mixed solution is heated at 200 DEG C for 10 min; the obtained solution is centrifuged and cleaned with ethanol and toluene for 2-3 times to obtain the crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0016] Further, in step 1, the sample is separated from the reaction solution by using acetone in the first cleaning, and the volume ratio of acetone to the reaction solution is 3:1; and in the subsequent cleaning process, a mixed solution of deionized water, ethanol and acetone is used, and the volume ratio of deionized water, ethanol and acetone is 1:1:10.
[0017] Further, in step 2, the cleaning is performed for 3 times, and the volume ratio of deionized water to ethanol used in the cleaning process is 1:5.
[0018] Further, in step 3, the cleaning is performed for 3 times, and the volume ratio of ethanol to toluene used in the cleaning process is 1:1.
[0019] Compared with the prior art, the present application has the following beneficial effects:
[0020] 1. The present application successfully uses non-metal elements to dope carbon, nitrogen and phosphorus for the first time to prepare the crystalline PdCN@amorphous PdP core-shell nanoparticles with uniform size.
[0021] 2. The reagents used in the present application can be purchased on the market without further treatment, the preparation method is simple, and the required equipment is all basic laboratory equipment without expensive equipment. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 Fig. 1 is the X-ray diffraction (XRD) pattern of the cubic Pd nanoparticles, the cubic PdCN nanoparticles and the crystalline PdCN@amorphous PdP core-shell nanoparticles prepared in Example 1; wherein (a) is the XRD pattern of the cubic Pd nanoparticles; (b) is the XRD pattern of the cubic PdCN nanoparticles; and (c) is the XRD pattern of the crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0023] Figure 2 Fig. 2 is the transmission electron microscope (TEM) picture of the crystalline PdCN@amorphous PdP core-shell nanoparticles prepared in Example 1; wherein (a) is the TEM picture at a scale of 50 nm; and (b) is the TEM picture at a scale of 10 nm.
[0024] Figure 3 Fig. 3 is the scanning electron microscope picture of the crystalline PdCN@amorphous PdP core-shell nanoparticles prepared in Example 1.
[0025] Figure 4These are the X-ray diffraction (XRD) patterns of cubic Pd nanoparticles, cubic PdCN nanoparticles, and crystalline PdCN@amorphous PdP core-shell nanoparticles prepared in Example 2; (a) is the XRD pattern of cubic Pd nanoparticles; (b) is the XRD pattern of cubic PdCN nanoparticles; and (c) is the XRD pattern of crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0026] Figure 5 These are transmission electron microscope (TEM) images of the crystalline PdCN@amorphous PdP core-shell nanoparticles prepared in Example 2; (a) is a TEM image at a 50 nm scale; and (b) is a TEM image at a 10 nm scale.
[0027] Figure 6 3 is a scanning electron microscope image of the crystalline PdCN@amorphous PdP core-shell nanoparticles prepared in Example 2. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and Examples. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. Unless otherwise specified, all reagents used are commercially available products and are not required to be further purified.
[0029] The specific implementation of the present invention is described in detail below with reference to specific embodiments.
[0030] Example 1: Synthesis of crystalline PdCN@amorphous PdP core-shell nanoparticles;
[0031] A method for synthesizing crystalline PdCN@amorphous PdP core-shell nanoparticles comprises the following steps:
[0032] 1) 1.05 g of polyvinyl pyrrolidone, 0.6 g of L-ascorbic acid, and 6 g of potassium bromide were added to 80 mL of deionized water to form a mixed solution. The oil bath was preheated for approximately 10 min until the temperature reached 85°C. 30 mL of a 0.065 mol / L sodium chloropalladate solution was rapidly injected into the mixed solution. The mixed solution was then transferred to an oil bath and reacted at 85°C for 3 h. The temperature was then lowered to room temperature. The resulting solution was centrifuged and washed with deionized water, ethanol, and acetone to obtain cubic Pd nanoparticles, which were then dried for later use.
[0033] The cleaning times were 3 times. During the first cleaning, acetone was used to separate the sample from the reaction liquid, and the volume ratio of acetone to the reaction liquid was 3:1. In the subsequent cleaning process, a mixture of deionized water, ethanol and acetone was used, and the volume ratio of deionized water, ethanol and acetone was 1:1:10.
[0034] 2) Weigh 0.03 g of cubic Pd nanoparticles and dissolve them in 60 mL of dimethyl sulfoxide solution. The mixture is transferred to a reactor and reacted at 180°C for 2 h. The resulting solution is centrifuged and washed three times with deionized water and ethanol to obtain cubic PdCN nanoparticles, which are then dried at 40°C for storage.
[0035] The number of cleaning times was 3, and the volume ratio of deionized water and ethanol used in the cleaning process was 1:5.
[0036] 3) Weigh 21 mg of cubic PdCN nanoparticles and mix with 77 mL of oleylamine solution. Add 7 mL of trioctylphosphine solution, and heat the mixture at 200°C for 10 min. The resulting solution is centrifuged and washed three times with ethanol and toluene to obtain crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0037] The number of cleaning times was 3, and the volume ratio of ethanol and toluene used in the cleaning process was 1:1.
[0038] The XRD pattern of the sample prepared in this embodiment is as follows Figure 1 Transmission electron microscopy and element distribution photos are shown in Figure 2 , SEM and element distribution photos are shown in Figure 3 . The XRD spectrum shows that the product is crystalline PdCN@amorphous PdP core-shell nanoparticles. By comparison with the standard PdXRD spectrum, it was found that the characteristic peaks of the synthesized PdCN nanocrystals shifted to a small angle compared with the standard Pd XRD card JCPDS-46-1043, indicating that C and N successfully entered the Pd lattice to form PdCN nanocubes; after introducing P on the basis of PdCN, the XRD characteristic peak position of the obtained nanocrystals was almost the same as that of PdCN, indicating that the crystalline part was still PdCN. Transmission electron microscopy and element distribution photos and scanning electron microscopy and element distribution photos show that the synthesized nanocrystals are uniform in size, and the Pd, C, N, and P elements are evenly distributed in the nanoparticles, indicating that this example successfully synthesized crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0039] Example 2: Synthesizing crystalline PdCN@amorphous PdP core-shell nanoparticles by changing the reaction temperature;
[0040] A method for synthesizing crystalline PdCN@amorphous PdP core-shell nanoparticles by changing the reaction temperature comprises the following steps:
[0041] 1) is the same as step 1) in Example 1.
[0042] 2) is the same as step 2) in Example 1.
[0043] 3) Weigh 21 mg of cubic PdCN nanoparticles and mix with 77 mL of oleylamine solution. Add 7 mL of trioctylphosphine solution, and heat the mixture at 195°C for 10 min. Centrifuge and wash the resulting solution three times with ethanol and toluene to obtain crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0044] The number of cleaning times was 3, and the volume ratio of ethanol and toluene used in the cleaning process was 1:1.
[0045] The XRD pattern of the sample prepared in this embodiment is as follows Figure 4 Transmission electron microscopy and element distribution photos are shown in Figure 5 , SEM and element distribution photos are shown in Figure 6 . The XRD spectrum shows that the product is crystalline PdCN@amorphous PdP core-shell nanoparticles. By comparison with the standard PdXRD spectrum, it was found that the characteristic peaks of the synthesized PdCN nanocrystals shifted to a small angle compared with the standard Pd XRD card JCPDS-46-1043, indicating that C and N successfully entered the Pd lattice to form PdCN nanocubes; after introducing P on the basis of PdCN, the XRD characteristic peak position of the obtained nanocrystals was almost the same as that of PdCN, indicating that the crystalline part was still PdCN. Transmission electron microscopy and element distribution photos and scanning electron microscopy and element distribution photos show that the synthesized nanocrystals are uniform in size, and the Pd, C, N, and P elements are uniformly distributed in the nanoparticles. Compared with Example 1, the thickness of the amorphous shell synthesized in this example is thinner, indicating that this example successfully synthesized crystalline PdCN@amorphous PdP core-shell nanoparticles.
[0046] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.
Claims
1. A method for preparing crystalline PdCN@amorphous PdP core-shell nanoparticles, characterized in that: The following steps are involved: Step 1, preparing cubic Pd nanoparticles: 1.05g polyvinylpyrrolidone, 0.6g L-ascorbic acid and 6g potassium bromide were added to 80mL deionized water to form a mixed solution, the oil bath was preheated for 10min until the temperature reached 85°C, 30mL of 0.065mol / L sodium chloropalladate solution was quickly injected into the mixed solution, and the mixed solution was transferred to an oil bath, reacted at 85°C for 3h, and the temperature was lowered to room temperature; the resulting solution was centrifuged and washed 2-3 times with deionized water, ethanol and acetone to obtain cubic Pd nanoparticles, which were dried and set aside; in the first washing, acetone was used to separate the sample from the reaction solution, and the volume ratio of acetone to the reaction solution was 3:1; in the subsequent washing process, a mixture of deionized water, ethanol and acetone was used, and the volume ratio of deionized water, ethanol and acetone was 1:1:10; Step 2, preparing cubic PdCN nanoparticles: weighing 0.03 g of cubic Pd nanoparticles and dissolving them in 60 mL of dimethyl sulfoxide solution, transferring the mixture to a reactor, and reacting at 180° C. for 2 h; centrifuging the resulting solution and washing it 2-3 times with deionized water and ethanol to obtain cubic PdCN nanoparticles, which were then dried at 40° C. for storage; Step 3. Preparation of crystalline PdCN@amorphous PdP core-shell nanoparticles: Weigh 21 mg of cubic PdCN nanoparticles and mix with 77 mL of oleylamine solution, add 7 mL of trioctylphosphine solution, and heat the mixture solution at 200°C for 10 minutes; the resulting solution is centrifuged and washed with ethanol and toluene 2 to 3 times to obtain crystalline PdCN@amorphous PdP core-shell nanoparticles.
2. The method for preparing crystalline PdCN@amorphous PdP core-shell nanoparticles according to claim 1, characterized in that: In step 2, the washing times are 3 times, and the volume ratio of deionized water and ethanol used in the washing process is 1:
5.
3. The method for preparing crystalline PdCN@amorphous PdP core-shell nanoparticles according to claim 1, characterized in that: In step 3, the washing times are 3 times, and the volume ratio of ethanol and toluene used in the washing process is 1:1.