CN110732677A

CN110732677A - Preparation method of oil-soluble palladium nano-materials with controllable morphology

Info

Publication number: CN110732677A
Application number: CN201910987698.3A
Authority: CN
Inventors: 唐华东; 朱文仙; 欧阳杰
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-01-31

Abstract

The invention discloses a preparation method of morphology-controllable oil-soluble palladium nano-materials, which comprises the following steps of (1) preparing a palladium acetate precursor solution dissolved in a chloroform solvent, wherein the mass ratio of palladium salt to chloroform is 1: 1000-2500, (2) adding oleylamine and oleic acid into the chloroform solution obtained in the step (1) as protective agents, so that the mass ratio of palladium acetate, oleylamine and oleic acid is 1: 1.33-4.0: 1.48-4.45, (3) adding diethylsilane into the chloroform solution obtained in the step (2) in a step, so that the mass ratio of palladium acetate to diethylsilane is 1:1, stirring and reacting the solution at room temperature for 2-8 hours, so as to obtain a palladium nano-particle chloroform solution, and (4) adding methanol into the palladium nano-particle chloroform solution, and centrifuging to obtain black palladium nano-particle precipitates.

Description

Preparation method of oil-soluble palladium nano-materials with controllable morphology

Technical Field

The invention relates to the field of nano materials, and mainly provides a preparation method of oil-soluble palladium nano materials.

Background

The method for synthesizing nano palladium particles at present can be divided into a physical method and a chemical method, the physical method mainly comprises an evaporation condensation method, a plasma deposition method, a sputtering method, a physical crushing method and the like, the physical method can prepare the nano palladium particles in large batch, but the preparation process is complex, the product quality is poor, and the particle size distribution is uneven, the chemical method is to operate substances from a molecular level, the palladium nano particles prepared by a homogeneous solution through a chemical reaction are beneficial to controlling the large size and the uniform solubility of the particles , so that technical workers prepare the palladium nano materials by a thermal decomposition method, a microwave radiation method, an ultrasonic radiation method, a chemical reduction method and other chemical methods, the chemical reduction method obtains the palladium nano particles by adding reductive amines, hydrogen, alcohols and the like into metal salts of palladium, and simultaneously adding a proper protective agent to prevent the nano palladium from agglomerating, the method has the advantages of mild research, early preparation reaction, simple operation conditions of the palladium nano particles, and the like, and the defects of the traditional polar reduction method that the nano particles are difficult to be prepared by adding reductive amines, hydrogen, alcohols and the traditional polar solvent and the polar solvent has the advantages of the traditional method of preparing the nano palladium.

Disclosure of Invention

The invention aims to provide simple chemical reduction methods for preparing the palladium nano material soluble in the oil phase solvent, the preparation method has mild reaction conditions, simple preparation process, easy large-scale production, short production period, uniform particle size distribution of the obtained palladium nano particles and high stability.

In order to realize the above, the invention adopts the following technical scheme:

A preparation method of oil-soluble palladium nano-materials, which comprises the steps of adding palladium acetate, oleylamine, oleic acid and diethyl silane reducing agent into chloroform solvent at room temperature to obtain palladium nano-particles, controlling the appearance of the nano-particles by the ratio of oleylamine to oleic acid, and the specific steps are as follows:

(1) preparing a palladium acetate precursor solution dissolved in a chloroform solvent, wherein the mass ratio of palladium salt to chloroform is 1: 1000-2500;

(2) adding oleylamine and oleic acid into the chloroform solution obtained in the step (1) as a protective agent, wherein the mass ratio of palladium acetate to oleylamine to oleic acid is 1: 1.33-4.0: 1.48-4.45;

(3) adding steps of diethylsilane into the chloroform solution obtained in the step (2) to enable the mass ratio of palladium acetate to diethylsilane to be 1:1, stirring the solution at room temperature to react for 2-8 hours, and finally obtaining a chloroform solution of palladium nanoparticles;

(4) adding methanol into chloroform solution of palladium nano-particles, centrifuging to obtain black palladium nano-particle precipitate, and dispersing the precipitate in toluene or n-hexane to obtain oil phase solution of palladium nano-particles.

The invention has the advantages that:

, the palladium nano-materials with three morphologies (including spherical palladium nano-particles, vermicular palladium nano-particles and cauliflower palladium nano-particles) are synthesized by a room temperature step method, and the method is simple and easy to implement and has high experimental reproducibility.

Secondly, the particle size distribution of the palladium nano particles is uniform, and the morphology of the palladium nano material is controlled by changing the ratio of oleylamine to oleic acid.

Thirdly, the reaction condition is mild, the preparation process is simple, and the large-scale production is easy.

Drawings

FIG. 1 is a transmission electron micrograph of spherical palladium nanoparticles obtained in example 1 of the present invention;

FIG. 2 is a TEM image of spherical Pd nanoparticles obtained in example 2 of the present invention;

FIG. 3 is a TEM image of cauliflower-like Pd nanoparticles obtained in example 3 of the present invention;

FIG. 4 is a TEM image of cauliflower-like Pd nanoparticles obtained in example 4 of the present invention;

FIG. 5 is a TEM image of the vermicular Pd nanoparticles obtained in example 5 of the present invention;

FIG. 6 is an EDX spectrum of the vermicular palladium nanoparticles obtained in example 5 of the present invention.

Detailed Description

Further details of the practice of the invention will be illustrated by the following examples, which are intended to be non-limiting of the invention, the particular materials and amounts thereof recited in the examples, as well as other details, the materials, instruments and methods of testing used in the practice of the invention are set forth below.

Reagent material

Palladium acetate (AR, Pd: 46.0-48.0%, Aladdin); trichloromethane (CHCl)₃AR, shanghai lingfeng chemical reagents ltd); oleylamine (C)₁₈H₃₇N, 80.0% -90.0%, Aladdin); oleic acid (C)₁₈H₃₂O₂AR, Aladdin); diethylsilane (98.0%, aladin).

Test method

The morphology and the particle size distribution of the palladium nanoparticles are observed by a transmission electron microscope (TEM, the Netherlands FEITecnai G2F 30) to obtain a TEM image of the nanoparticles and an energy dispersive X-ray (EDX) energy spectrum.

Example 1:

weighing 3.0mg of palladium acetate into a reaction tube, adding 3mL of chloroform, stirring until the palladium acetate is completely dissolved, wherein the solution is bright yellow, then sequentially adding 15 mu L of oleylamine and 15 mu L of oleic acid as protective agents, adding 4.4 mu L of diethylsilane under the stirring action, and stirring at room temperature for 8 hours to react to obtain a black palladium nanoparticle chloroform solution. Adding excessive methanol into the chloroform solution, centrifuging to obtain black precipitate, adding 3mL of toluene into the precipitate, and performing ultrasonic dispersion for 1 minute to obtain a toluene solution of the palladium nanoparticles. A trace amount of toluene solution is dripped on a copper net of an electron microscope and is placed under a transmission electron microscope for observation, and the morphology of the obtained palladium nano-particles is shown in figure 1. As can be seen from FIG. 1, the obtained palladium nanoparticles are spherical particles with uniform particle size distribution, and the average particle size of the spherical palladium nanoparticles is 8.1 + -0.7 nm obtained by computer software statistics.

Example 2:

weighing 3.0mg of palladium acetate into a reaction tube, adding 5mL of chloroform, stirring until the palladium acetate is completely dissolved, wherein the solution is bright yellow, then sequentially adding 10 mu L of oleylamine and 10 mu L of oleic acid as protective agents, adding 4.4 mu L of diethylsilane under the stirring action, and stirring at room temperature for 5 hours to react to obtain a black palladium nanoparticle chloroform solution. Adding excessive methanol into the chloroform solution, centrifuging to obtain black precipitate, adding 5mL of toluene into the precipitate, and performing ultrasonic dispersion for 1 minute to obtain a toluene solution of the palladium nanoparticles. A trace amount of toluene solution is dripped on a copper mesh of an electron microscope and is observed under a transmission electron microscope, and the morphology of the obtained palladium nano-particles is shown in figure 2. As can be seen from FIG. 2, the obtained palladium nanoparticles are spherical particles with uniform particle size distribution, and the average particle size of the spherical palladium nanoparticles is 9.3 +/-0.6 nm as calculated by computer software.

Example 3:

weighing 3.0mg of palladium acetate into a reaction tube, adding 3mL of chloroform, stirring until the palladium acetate is completely dissolved, wherein the solution is bright yellow, then sequentially adding 15 mu L of oleylamine and 5 mu L of oleic acid as protective agents, adding 4.4 mu L of diethylsilane under the stirring action, and stirring at room temperature for reaction for 5 hours to obtain a black palladium nanoparticle chloroform solution. Adding excessive methanol into the chloroform solution, centrifuging to obtain black precipitate, adding 3mL of n-hexane into the precipitate, and performing ultrasonic dispersion for 1 minute to obtain an n-hexane solution of the palladium nanoparticles. A trace amount of n-hexane solution was dropped on a copper mesh of an electron microscope and observed under a transmission electron microscope, and the morphology of the obtained palladium nanoparticles is shown in FIG. 3. As can be seen from FIG. 3, the obtained palladium nanoparticles are cauliflower-shaped, the particle size distribution is uniform, and the average particle size of the cauliflower-shaped nanoparticles is 24.3 +/-1.9 nm as calculated by computer software.

Example 4:

weighing 3.0mg of palladium acetate into a reaction tube, adding 2mL of chloroform, stirring until the palladium acetate is completely dissolved, wherein the solution is bright yellow, then sequentially adding 15 mu L of oleylamine and 5 mu L of oleic acid as protective agents, adding 4.4 mu L of diethylsilane under the stirring action, and stirring at room temperature for 8 hours to react to obtain a black palladium nanoparticle chloroform solution. Adding excessive methanol into the chloroform solution, centrifuging to obtain black precipitate, adding 3mL of n-hexane into the precipitate, and performing ultrasonic dispersion for 1 minute to obtain an n-hexane solution of the palladium nanoparticles. A trace amount of n-hexane solution was dropped on a copper mesh of an electron microscope and observed under a transmission electron microscope, and the morphology of the obtained palladium nanoparticles is shown in FIG. 4. As can be seen from FIG. 4, the obtained palladium nanoparticles are cauliflower-shaped, the particle size distribution is relatively uniform, and the average particle size of the cauliflower-shaped nanoparticles is 27.3 +/-3.7 nm as calculated by computer software.

Example 5:

weighing 3.0mg of palladium acetate in a test tube, adding 3mL of chloroform, stirring until the palladium acetate is completely dissolved, wherein the solution is bright yellow, then sequentially adding 5 mu L of oleylamine and 15 mu L of oleic acid as protective agents, adding 4.4 mu L of diethylsilane under the stirring action, and stirring at room temperature for reaction for 2 hours to obtain a black palladium nanoparticle chloroform solution. Adding excessive methanol into the chloroform solution, centrifuging to obtain black precipitate, adding 3mL of toluene into the precipitate, and performing ultrasonic dispersion for 1 minute to obtain a toluene solution of the palladium nanoparticles. A trace amount of toluene solution was dropped on a copper mesh of an electron microscope and observed under a transmission electron microscope, and the morphology of the obtained palladium nanoparticles is shown in FIG. 5. As can be seen from FIG. 5, the obtained palladium nanoparticles are vermicular, and the length of the vermicular palladium nanoparticles is about 10-30 nm, and the diameter of the vermicular palladium nanoparticles is about 2-4 nm.

Example 6:

a toluene solution of the vermicular palladium nanoparticles was prepared according to the reaction conditions of example 5, a trace amount of toluene solution was dropped on a copper mesh of an electron microscope and placed under a transmission electron microscope to observe to obtain images of the vermicular palladium nanoparticles, and areas where the vermicular palladium nanoparticles are dense were selected from the images to perform energy dispersive X-ray energy spectroscopy (EDX) analysis, and the obtained results are shown in fig. 6. In fig. 6, the Pd line is from palladium nanoparticles, the Cu line is from electron microscopy copper mesh, the C line is from electron microscopy copper mesh carbon support film, and the Si and O lines are from the redox reaction of diethylsilane and palladium acetate.

Claims

1, preparation methods of oil-soluble palladium nano-materials, characterized by that, the preparation method includes the following steps: