CN109894085B

CN109894085B - Simple universal preparation method for in-situ embedding of monodisperse phenolic resin nanorods into MOF (Metal organic framework) composite material

Info

Publication number: CN109894085B
Application number: CN201910221887.XA
Authority: CN
Inventors: 周亮; 吕建帅; 麦立强; 于强
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2019-03-22
Filing date: 2019-03-22
Publication date: 2022-03-11
Anticipated expiration: 2039-03-22
Also published as: CN109894085A

Abstract

The invention relates to a simple universal preparation method of a monodisperse phenolic resin nanorod in-situ embedded MOF composite material, which comprises the following steps: uniformly dispersing the monodisperse phenolic resin nanorods in the solution, adding metal salt, stirring, performing ultrasonic treatment, finally adding the solution containing organic ligands at a certain concentration, reacting, centrifuging, washing and drying to obtain the monodisperse phenolic resin nanorods in-situ embedded MOF composite material. Compared with the prior art, the invention has the following advantages: the synthesis process is simple and the cost is low; the conductivity and electrochemical performance of the material can be effectively improved by in-situ N doping; the particle size of the MOF is adjustable, the MOF can be stably embedded or inserted into a monodisperse resin nanorod structure, and the whole structure is stable; the one-dimensional nanorods effectively utilize the interior of the large-particle-size MOF, shorten the transmission path of electrons and reduce the diffusion resistance of the electrons.

Description

Simple universal preparation method for in-situ embedding of monodisperse phenolic resin nanorods into MOF (Metal organic framework) composite material

Technical Field

The invention belongs to the field of material chemistry, and particularly relates to a simple universal preparation method of a monodisperse phenolic resin nanorod in-situ embedded MOF composite material.

Background

The MOF material has been widely used in the fields of gas adsorption separation, ion exchange, etc. because of its advantages of high thermal and chemical stability and abundant pores. When used as electrode materials, the larger voids and closed structures of MOF nanocrystals are used to store electrons and ions and buffer volume expansion; the porous or hollow carbon framework has high local conductivity and overall conductivity, and is beneficial to accelerating the transmission speed of ions or electrons and improving the electrochemical performance of the porous or hollow carbon framework.

At present, the particle size of MOF materials is mostly about 1 micron, and the larger particle size makes the internal electronic transmission path and resistance larger, so that the electrochemical performance of the MOF materials is difficult to improve and further apply. Opening up large particle size MOF materials in a "tunnel" fashion would greatly increase the space available within them. From current literature research, only researchers have penetrated carbon nanotubes into MOF materials, but the penetration efficiency is not high. In addition, if the carbon nanotubes are to adsorb metals, the surfaces of the carbon nanotubes need to be pretreated with nitric acid or sulfuric acid to add organic functional groups, which greatly increases the practical application cost of the carbon nanotubes. Chen et al (j.am.chem.soc.,2017,139,12710) designed a structure in which carbon nanotubes were inserted into ZIF-67, greatly increasing its internal utilization efficiency and electron transmission speed. But the carbon nano tube still needs sulfuric acid and nitric acid for treatment, has higher cost and is difficult to be produced commercially. Therefore, the synthesis of the MOF composite material with the simple one-dimensional structure and the large particle size inserted in situ plays an important role in practical application.

Disclosure of Invention

The invention aims to provide a simple universal preparation method for in-situ embedding of monodisperse phenolic resin nanorods into an MOF composite material, which has the advantages of simple process, mild conditions, low cost and strong universality.

The scheme adopted by the invention for solving the technical problems is as follows: the simple universal preparation method of the monodisperse phenolic resin nanorod in-situ embedded MOF composite material comprises the following steps: uniformly dispersing the monodisperse phenolic resin nanorods in the solution, adding metal salt, stirring, performing ultrasonic treatment, finally adding the solution containing organic ligands at a certain concentration, reacting, centrifuging, washing and drying to obtain the monodisperse phenolic resin nanorods in-situ embedded MOF composite material.

According to the scheme, the selected metal salt is zinc nitrate hexahydrate, cobalt nitrate hexahydrate, ferric trichloride or nickel acetate tetrahydrate.

According to the scheme, the concentration of the zinc nitrate hexahydrate is 15-30 mg/mL; the concentration of the cobalt nitrate hexahydrate is 10-200 mg/mL; the concentration of ferric trichloride is 20-40 mg/mL; the concentration of the nickel acetate tetrahydrate is 5-20 mg/mL.

According to the scheme, the organic ligand is dimethyl imidazole, terephthalic acid or polyvinylpyrrolidone.

According to the scheme, the concentration of the dimethyl imidazole solution is 10-40 mg/mL; the concentration of the terephthalic acid solution is 10-20 mg/mL; the concentration of the polyvinylpyrrolidone solution is 10-50 mg/mL.

According to the scheme, the reaction temperature is 20-40 ℃, and the stirring time is 6-18 h.

The reaction mechanism of the invention is as follows: the monodisperse phenolic resin nanorod has abundant oxygen-containing functional groups on the surface, and can effectively adsorb metal ions. When immersed in a metal solution, a large amount of metal ions are adsorbed to the surface and inside of the resin nanorods; after the organic ligand is added, the organic ligand and the metal start to form a ligand and nucleate on the surface of the resin nanorod; the concentration of the organic ligand is critical to the extent of nucleation. When the concentration is lower, nucleation is less, and the MOF grows into large-particle-size MOF gradually along with the prolonging of the reaction time; when the concentration is higher, the nucleation is increased, the MOF with small particle size is obtained firstly, and the MOF nano-crystals with small particle size are obtained finally due to more nucleation and limited number of metal ions. As the MOF grows on the resin nano-rod in situ, the stable structure of the nano-rod penetrating into the MOF is finally obtained.

Compared with the prior art, the invention has the following advantages:

1) the synthesis process is simple and the cost is low;

2) the conductivity and electrochemical performance of the material can be effectively improved by in-situ N doping;

3) the particle size of the MOF is adjustable, the MOF can be stably embedded or inserted into a monodisperse resin nanorod structure, and the whole structure is stable;

4) the one-dimensional nanorods effectively utilize the interior of the large-particle-size MOF, shorten the transmission path of electrons and reduce the diffusion resistance of the electrons;

5) the synthesis method has strong universality, and the phenolic resin nanorod in-situ interpenetrated embedded large-particle-size ZIF-8, ZIF-67, Zn/Co-ZIF, Fe-Mil-88 and Ni-based MOFs materials can be prepared according to the synthesis route.

Drawings

FIG. 1 is an XRD pattern, a schematic microstructure and an SEM image of a large particle size ZIF-8 composite material in-situ embedded with monodisperse phenolic resin nanorods obtained in example 1;

FIG. 2 is an SEM image of a small particle size ZIF-8 in-situ embedded monodisperse phenolic resin nanorod composite material obtained in example 2;

FIG. 3 is an XRD pattern, a schematic microstructure and an SEM image of the large particle size ZIF-67 composite material in-situ embedded with monodisperse phenolic resin nanorods obtained in example 3;

FIG. 4 is an XRD pattern, a schematic microstructure and an SEM image of the in-situ embedded large-particle-size Zn/Co-ZIF composite material of the monodisperse phenolic resin nanorod obtained in example 4;

FIG. 5 is an XRD pattern, a schematic microstructure and an SEM image of the in-situ embedded large-particle-size Fe-MIL-88 composite material of the monodisperse phenolic resin nanorod obtained in example 5;

FIG. 6 is an XRD pattern, a schematic microstructure diagram and an SEM image of the monodisperse phenolic resin nanorod in-situ embedded large-particle-size Ni-MOF composite material obtained in example 6.

Detailed Description

The following examples are given to further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.

Example 1

Dispersing 200mg of monodisperse phenolic resin nanorods and 508mg of zinc nitrate hexahydrate in 25mL of methanol solution, then uniformly adsorbing metal zinc ions through ultrasonic dispersion, adding 25mL of methanol solution dissolved with 330mg of dimethyl imidazole, stirring and reacting for 12h at 25 ℃, centrifuging, washing and drying to obtain the monodisperse phenolic resin nanorods in-situ embedded large-particle-size ZIF-8 composite material (RNR/L-ZIF-8).

The large particle size ZIF-8 composite material is embedded in the monodisperse phenolic resin nanorods obtained in the embodiment as an example. The monodisperse phenolic resin nanorod has abundant oxygen-containing functional groups on the surface, and can effectively adsorb metal ions. When immersed in a metal solution, a large amount of metal ions are adsorbed to the surface and inside of the resin nanorods; after the dimethyl imidazole is added, the dimethyl imidazole and metal ions start to form a ligand and nucleate on the surface of the resin nanorod; this example shows lower concentrations of dimethylimidazole, less nucleation, and gradual growth to large particle size ZIF-8 with longer reaction times. The crystallinity of RNR/L-ZIF-8 is high as can be obtained by X-ray diffraction pattern analysis shown in figure 1 a; the microstructure schematic diagram and SEM image of the in-situ interpenetration ZIF-8 composite material of the phenolic resin nanorods shown in the attached figures 1 b-d show that the monodisperse phenolic resin nanorods are successfully interpenetrated into ZIF-8 crystals, the ZIF-8 crystals are regular dodecahedral structures, and the average grain size is about 700nm, which proves that the synthesis mechanism has rationality.

After the material is carbonized, the internal utilization space of the large-particle ZIF-8 is effectively increased, the electron transmission efficiency is improved, and the conductivity is increased. Meanwhile, the ZIF-8 is connected by the excellent one-dimensional structure, and the electron transmission efficiency is further improved. In addition, the material has high practical application value in the fields of gas adsorption, separation, energy storage (lithium battery, sodium battery and the like) and conversion by combining with high specific surface area.

Example 2

Dispersing 200mg of monodisperse phenolic resin nanorods and 508mg of zinc nitrate hexahydrate in 25mL of methanol solution, then uniformly adsorbing metal zinc ions through ultrasonic dispersion, adding 25mL of methanol solution dissolved with 990mg of dimethyl imidazole, stirring and reacting for 12 hours at 25 ℃, centrifugally washing and drying to obtain the small-particle-size ZIF-8 in-situ embedded monodisperse phenolic resin nanorod composite material (S-ZIF-8/RNR).

As shown in an SEM image of the attached figure 2, the small-particle-size ZIF-8 is successfully embedded into a monodisperse phenolic resin nanorod structure in situ, and the average particle size of the ZIF-8 is about 110 nm. The existence of the one-dimensional nanorod structure avoids the agglomeration phenomenon of the small-particle-size ZIF-8.

Example 3

Dispersing 40mg of monodisperse phenolic resin nanorods and 2.5g of cobalt nitrate hexahydrate in 15mL of methanol solution, then uniformly adsorbing metal cobalt ions through ultrasonic dispersion, adding 15mL of methanol solution dissolved with 1.3g of dimethyl imidazole, stirring and reacting for 12 hours at room temperature, centrifugally washing, and drying to obtain the monodisperse phenolic resin nanorods in-situ embedded ZIF-67 composite material (RNR/L-ZIF-67).

As shown in FIG. 3a, it was found that RNR/L-ZIF-67 had high crystallinity by XRD analysis. And the attached figures 3 b-d are a microstructure schematic diagram and an SEM (scanning electron microscope) diagram of the large-particle-size ZIF-67 composite material in-situ penetrated and embedded by the monodisperse phenolic resin nanorods, which show that the monodisperse phenolic resin nanorods are successfully embedded into ZIF-67 crystals in situ, the ZIF-67 crystals are regular dodecahedrons, and the average particle size is about 600 nm.

Example 4

1) Dispersing 150mg of monodisperse phenolic resin nanorods, 385mg of cobalt nitrate hexahydrate and 60mg of zinc nitrate hexahydrate in 25mL of methanol solution, uniformly adsorbing metal cobalt ions and zinc ions through ultrasonic dispersion, adding 25mL of methanol solution dissolved with 990mg of dimethyl imidazole, stirring and reacting for 12 hours at room temperature, centrifugally washing and drying to obtain the monodisperse phenolic resin nanorods in-situ embedded Zn/Co-ZIF composite materials (RNR/L-Zn/Co-ZIF).

As shown in FIG. 4a, the crystallinity of RNR/L-Zn/Co-ZIF was high as determined by XRD analysis. FIGS. 4b to d are a schematic microstructure diagram and SEM (scanning electron microscope) diagram of the in-situ embedding Zn/Co-ZIF composite material of the monodisperse phenolic resin nanorod, and show that the monodisperse phenolic resin nanorod is successfully embedded and interpenetrated in the large-particle-size Zn/Co-ZIF crystal in situ, the Zn/Co-ZIF crystal is a regular dodecahedron, and the average particle size is about 600 nm.

Example 5

Dispersing 200mg of monodisperse phenolic resin nanorods, 300mg of ferric trichloride and 200mg of terephthalic acid in 12mL of N, N-dimethylformamide solution, uniformly adsorbing metallic iron ions through ultrasonic dispersion, dropwise adding 0.5mL of polyvinylpyrrolidone (PVP) solution (8g of PVP is dissolved in 12mL of N, N-dimethylformamide solution), condensing and refluxing at 145 ℃, stirring for reaction for 1.5h, finally performing centrifugal washing and drying to obtain the monodisperse phenolic resin nanorods in-situ embedded large-particle-size Fe-MIL-88 composite material (RNR/L-Fe-MIL-88).

As shown in FIG. 5a, the crystallinity of RNR/L-Fe-MIL-88 was high as determined by XRD analysis. FIGS. 5 b-d are schematic microstructure and SEM images of the in-situ embedded large-particle-size Fe-MIL-88 composite material of the monodisperse phenolic resin nanorods, which show that the monodisperse phenolic resin nanorods are successfully embedded in the Fe-MIL-88 crystals in situ, and the Fe-MIL-88 crystals are hexaprism-shaped.

Example 6

Dispersing 150mg of monodisperse phenolic resin nanorods and 350mg of nickel acetate tetrahydrate in 50mL of ethanol solution, and then adding 0.75g of PVP; after the metal nickel ions are uniformly adsorbed by ultrasonic dispersion, the mixture is condensed and refluxed at the temperature of 90 ℃, and is stirred for reaction for 10 hours; finally, centrifugal washing and drying are carried out to obtain a monodisperse phenolic resin nanorod in-situ embedded large-particle-size Ni-MOF composite material (RNR/L-Ni-MOF);

as shown in FIG. 6a, the crystallinity of RNR/L-Ni-MOF was very high by XRD analysis. FIGS. 6b to d are schematic structural diagrams and SEM images of the in-situ embedding of the monodisperse phenolic resin nanorods into the Ni-MOF composite material, which show that the monodisperse phenolic resin nanorods are successfully embedded into Ni-MOF crystals in situ, and the Ni-MOF crystals are cubic.

Claims

1. The simple universal preparation method of the monodisperse phenolic resin nanorod in-situ embedded MOF composite material comprises the following steps: uniformly dispersing phenolic resin nanorods in a solution, adding metal salt, stirring, performing ultrasonic treatment, finally adding a solution containing organic ligands at a certain concentration, reacting, centrifuging, washing and drying to obtain a monodisperse phenolic resin nanorod in-situ embedded MOF composite material;

the selected metal salt is zinc nitrate hexahydrate, cobalt nitrate hexahydrate, ferric trichloride or nickel acetate tetrahydrate;

the concentration of the zinc nitrate hexahydrate is 15-30 mg/mL; the concentration of the cobalt nitrate hexahydrate is 10-200 mg/mL; the concentration of ferric trichloride is 20-40 mg/mL; the concentration of the nickel acetate tetrahydrate is 5-20 mg/mL;

the organic ligand is dimethyl imidazole, terephthalic acid or polyvinylpyrrolidone;

the concentration of the dimethyl imidazole solution is 10-40 mg/mL; the concentration of the terephthalic acid solution is 10-20 mg/mL; the concentration of the polyvinylpyrrolidone solution is 10-50 mg/mL.

2. The simple and universal preparation method of the monodisperse phenolic resin nanorod in-situ embedded MOF composite material as claimed in claim 1, wherein the reaction temperature is 20-40 ℃, and the stirring time is 6-18 h.