CN106540711A - A kind of method that green prepares Ag-ZnO grapheme foam nickel material - Google Patents

Abstract

The invention provides a green method for preparing silver-zinc oxide-graphene-nickel foam material. Mainly comprise the following process steps: 1. use chemical vapor deposition (CVD) to grow a layer of graphene on the foamed nickel substrate to prepare a three-dimensional graphene-foamed nickel substrate; _2. ZnCl and ammonia are dissolved in deionized water to fully Stir, and transfer the mixed solution to a polytetrafluoroethylene reactor, immerse the prepared three-dimensional graphene-nickel foam matrix in the solution, and place the reactor in a drying oven at 100°C-150°C for 1-3hrs; 3. Prepare a silver-arginine solution with silver nitrate and L-arginine at a certain molar concentration ratio, then immerse the zinc oxide-graphene-nickel foam composite in the silver-arginine solution, and self-assemble 12 Take it out at ‑18hrs, ultrasonically clean it with deionized water, put it directly into the ascorbic acid solution, take it out after 20‑50mins, wash it, and dry it to obtain a silver-zinc oxide-graphene-nickel foam composite material with stable quality.

Description

A green method for preparing silver-zinc oxide-graphene-nickel foam material

technical field

The invention relates to the preparation of silver-zinc oxide nanosheet-graphene-nickel foam composite material, and belongs to the technical field of material chemical preparation.

Background technique

Graphene is used as a carrier to form a composite material with metal oxides or active material metal particles. The synergistic effect of the two makes the composite material have excellent catalytic, electrochemical sensing and gas sensing properties. At present, a variety of graphene-based composite materials have been prepared. Among them, the composite material of graphene and zinc oxide has been well applied in the fields of electrochemical sensor, gas sensor and antibacterial. The study found that on the basis of the zinc oxide/graphene composite material, silver nanoparticles are modified, and the composite effect is better than that of the pure zinc oxide/graphene composite material. At present, the preparation of silver/zinc oxide/graphene composite materials mostly stays in the research of silver nanoparticles/zinc oxide nanorods/two-dimensional graphene film composite materials, and the preparation of silver/zinc oxide nanosheets/three-dimensional graphite There are few reports on the research of olefin composites. In addition, for the preparation of silver nanoparticles/zinc oxide nanorods/two-dimensional graphene film composite materials, a large number of toxic and dangerous chemical reagents are used in the raw materials, and in the process, the irradiation method is mainly used to reduce the adhesion of zinc oxide nanorods The silver ions on the surface make it difficult to control the size and distribution of the obtained silver nanoparticles. At the same time, there are very few silver ions that can be reduced, and the combination with the nano-oxidized rods is not strong, so that the silver nanoparticles are easily lost in the application, resulting in a decline in performance. In addition, the chemical reagent L-arginine used in this method, as an important component of proteins, mainly acts as a linker. It is currently concentrated in the field of biomedicine, and its application in material chemical preparation technology is extremely rare. , it needs to be well utilized as a green linking agent. Moreover, in order to respond to the needs of environmental protection, green methods to prepare composite materials with good electrochemical properties are also urgently needed to be discovered.

Contents of the invention

Technical problem: the purpose of this invention is to provide a method for preparing silver-zinc oxide nanosheet-graphene/nickel foam composite material, which combines hydrothermal method and in-situ reduction method, and prepares uniform Zinc oxide nanosheets grown on the surface of graphene/nickel foam substrate, and using zinc oxide nanosheets as a platform, using non-toxic raw materials L-arginine and ascorbic acid as linkers and reducing agents to reduce the size on the surface of zinc oxide nanosheets and uniformly distributed spherical silver particles. The method has the advantages of low cost, simple operation, high efficiency, and stable large-scale preparation.

Technical solution: A method for preparing silver-zinc oxide nanosheet-graphene-nickel foam composite material according to the present invention comprises the following steps:

a. Preparation of graphene-nickel foam: using nickel foam as the substrate, the substrate is first ultrasonically cleaned with ethanol for 10-15mins, and then ultrasonically cleaned with deionized water for 10-15mins to remove impurities on the surface of nickel foam; After drying, put it into a tube furnace to evacuate, pass in argon gas 100-200sccm and hydrogen gas 100-200sccm, heat up to 800°C-1200°C at a speed of 10°C-20°C/mins, and anneal at this temperature for 20 -30mins; feed CH ₄ 10-20sccm and H ₂ 100-200sccm when growing graphene, disconnect CH ₄ after 10-15mins of growth, and quickly cool down, and take out the sample after the furnace cools down to room temperature;

b. Preparation of zinc oxide nanosheets-graphene _- nickel foam: Dissolve 0.05-1.00mol of ZnCl in deionized water and stir thoroughly, then add ammonia water and stir, accompanied by white precipitation, and get a white mixed solution after stirring evenly; Then the white mixed solution was transferred to a polytetrafluoroethylene reactor, and the prepared foamed graphene-nickel was immersed in the solution, and the reactor was placed in a vacuum drying oven at 100°C-140°C for 1-3hrs, and the reactor was cooled to At room temperature, the samples were taken out, rinsed, and dried;

c. Configuration of silver nitrate-arginine mixed solution: the molar concentration ratio of silver nitrate and L-arginine is 5:1-5:4, and the L-arginine solution whose concentration is 8-10mmol/L is configured, Use a sodium hydroxide solution with a mass concentration of 20% to adjust its pH to 9-11; then configure a silver nitrate solution with a concentration of 20-25mmol/L; then add the L-arginine solution dropwise to the silver nitrate solution , accompanied by a small amount of white precipitate, then stirred for 5-10mins;

d. self-assembly: Zinc oxide nanosheets-foamed graphene/nickel are immersed in the newly configured silver nitrate-arginine, and left standing in the dark for 10-18hrs;

e. In-situ reduction of silver particles: Take out the sample that has self-assembled for 12-18hrs, and after ultrasonic cleaning with deionized water for 10-20s, put the sample directly into the ascorbic acid solution with a concentration of 100-200mmol/L for 30-60min Then remove, rinse, and dry.

Beneficial effect: adopting the present invention, on the one hand, it can effectively solve the problem that the metal particles of the graphene-based active metal particle composite material are exposed to the application environment as much as possible without falling off so as to affect its performance and service life; On the one hand, the synthesis of the properties of graphene, zinc oxide and silver particles has also been realized, and the synergistic effect of their respective excellent electrical, catalytic and sensing properties has been fully utilized. In addition, in the preparation of the composite material, we choose the foamed graphene/nickel without skeleton as the substrate. This is because: first, graphene, a two-dimensional material, has low macroscopic strength, and graphene is prone to occur after removing the substrate. collapse, deformation or even fracture; second, the transfer process used to remove the substrate requires high skills and experience for the operator, and the process is cumbersome, which is not conducive to mass production; third, in the process of removing the substrate, there will be The use of some toxic chemical reagents is not only unfavorable to environmental safety, but also introduces impurities into graphene; fourth, after removing the substrate, graphene is very light and has hydrophobic properties, so it is still necessary to add a On the substrate, this makes the process more cumbersome and increases the production cost; fifth, retaining the nickel foam skeleton does not lose the advantages of graphene as a carrier of silver/zinc oxide nanosheets, which can be achieved in the comparative test of simply using nickel foam as the substrate. It can be seen that the composite with good structure cannot be prepared by using pure nickel foam, which may be related to the wrinkles on the surface of graphene. More importantly, L-arginine was used in the experiment. As a common amino acid, its molecular structure, charge distribution and ability to form multiple hydrogen bonds enable it to combine with negatively charged molecules, which is It is conducive to its self-assembly on zinc oxide nanosheets with n-type semiconductor characteristics; at the same time, L-arginine has a good combination with metal ions, especially better with silver ions. In this way, the effective and stable combination of graphene, zinc oxide and silver is realized, and the size of silver particles can be adjusted by adjusting the concentration of silver nitrate-arginine solution. In this method, the hydrothermal method and the in-situ reduction method are combined, the process is simple, the operation is convenient, the technical requirements are not high, it is easy to realize, and the environmental pollution is small, and it is a silver/zinc oxide nanosheet-graphene-nickel foam composite material The preparation provides an effective method.

Description of drawings

Figure 1 is a schematic diagram of the preparation of silver-zinc oxide nanosheet-graphene-nickel foam composite.

Fig. 2 is zinc oxide nanosheet-graphene-nickel foam composite.

Figure 3 is silver-zinc oxide nanosheet-graphene-nickel foam composite.

detailed description

a. Preparation of graphene-nickel foam: use nickel foam as the substrate (area density 200-400g ¹ m ^-2 , thickness 1-5mm, size 2-10cm ² ), the substrate is first ultrasonically cleaned with ethanol for 10-15mins , and then ultrasonically cleaned with deionized water for 10-15mins to remove impurities on the surface of the nickel foam. After the nickel foam is dried, put it into a tube furnace to evacuate, feed in Ar (100-200sccm) and H ₂ (100-200sccm), and raise the temperature to 800°C-1200°C at a rate of 10°C-20°C/mins. And anneal at this temperature for 20-30mins. When growing graphene, feed CH ₄ (10-20 sccm) and H ₂ (100-200 sccm), disconnect CH ₄ after 10-15 min of growth, and rapidly cool down for 20-30 min, and take out the sample after the furnace cools down to room temperature;

b. Preparation of zinc oxide nanosheet-graphene-nickel foam: Take 0.05-1.00mol of ZnCl ₂ dissolved in 20-50ml of deionized water and stir thoroughly, then add 2-5ml of ammonia water and stir, accompanied by white precipitation, stir evenly Finally, a white mixed solution is obtained; then the white mixed solution is transferred to a 50ml polytetrafluoroethylene reactor, and the prepared graphene/nickel foam is immersed in the solution, and the reactor is placed in a vacuum drying oven at 100°C-140°C for 1 -3hrs, after the reaction kettle is cooled to room temperature, the sample is taken out, rinsed, and dried;

c. Configuration of silver nitrate-arginine mixed solution: the molar concentration ratio of silver nitrate and L-arginine is 5:1-5:4, and 10-40ml of L-arginine solution (concentration is 8- 10mmol/L), add a certain amount of sodium hydroxide (mass concentration of 20%) solution, adjust its pH value to 9-11; then configure 30ml of silver nitrate solution (concentration of 20-25mmol/L); then L-fine The acid solution was added dropwise to the silver nitrate solution, accompanied by a small amount of white precipitate, and then stirred for 5-10mins;

d. self-assembly: Zinc oxide nanosheet-foamed graphene-nickel is immersed in the newly configured silver nitrate-arginine, and is left standing in the dark for 12-18hrs;

e. In-situ reduction of silver particles: Take out the sample that has self-assembled for 12-18hrs, and after ultrasonic cleaning with deionized water for 10-20s, put the sample directly into 20-60ml of ascorbic acid solution (concentration: 100-200mmol/L) After 30-60 minutes, take it out, wash it, and dry it.

The above is only the best implementation mode of the present invention, and the scope of protection of the present invention is not limited to the above-mentioned implementation mode, but all equivalent changes made by those skilled in the art according to the content of the present invention should be included in the claims within the scope of protection described in

Claims (1)

1. a green method for preparing silver-zinc oxide nanosheet-graphene-nickel foam composite material, is characterized in that the method may further comprise the steps: a. Preparation of graphene-nickel foam: using nickel foam as the substrate, the substrate is first ultrasonically cleaned with ethanol for 10-15 mins, and then ultrasonically cleaned with deionized water for 10-15 mins to remove impurities on the surface of the nickel foam; After the nickel foam is dried, it is placed in a tube furnace to evacuate, and argon 100-200sccm and hydrogen 100-200sccm are introduced, and the temperature is raised to 800-1200°C at a speed of 10°C-20°C/mins, and at this temperature Anneal for 20-30 mins; feed CH ₄ 10-20 sccm and H ₂ 100-200 sccm when growing graphene, disconnect CH ₄ after 10-15 min of growth, and quickly cool down, and take out the sample after the furnace cools to room temperature; b. Preparation of zinc oxide nanosheets-graphene-nickel foam: take 0.05-1.00mol of ZnCl ₂ dissolved in deionized water and stir thoroughly, then add ammonia water and stir, accompanied by white precipitation, and get a white mixed solution after stirring evenly; Then the white mixed solution was transferred to a polytetrafluoroethylene reactor, and the prepared foamed graphene-nickel was immersed in the solution, and the reactor was placed in a vacuum drying oven at 100°C-140°C for 1-3hrs, and the reactor was cooled to At room temperature, the samples were taken out, rinsed, and dried; c. Configuration of silver nitrate-arginine mixed solution: the molar concentration ratio of silver nitrate and L-arginine is 5:1-5:4, and the L-arginine solution whose concentration is 8-10mmol/L is configured, Use a sodium hydroxide solution with a mass concentration of 20% to adjust its pH to 9-11; then configure a silver nitrate solution with a concentration of 20-25mmol/L; then add the L-arginine solution dropwise to the silver nitrate solution , accompanied by a small amount of white precipitate, then stirred for 5-10mins; d. self-assembly: Zinc oxide nanosheets-foamed graphene/nickel are immersed in the newly configured silver nitrate-arginine, and left standing in the dark for 10-18hrs; e. In-situ reduction of silver particles: Take out the sample that has self-assembled for 12-18hrs, and after ultrasonic cleaning with deionized water for 10-20s, put the sample directly into the ascorbic acid solution with a concentration of 100-200mmol/L for 30-60min Then remove, rinse, and dry.