CN113040172A

CN113040172A - Reduced graphene oxide-metal/metal oxide functional composite material, preparation method and application thereof

Info

Publication number: CN113040172A
Application number: CN202110262074.2A
Authority: CN
Inventors: 陈春; 李涛; 韦革宏; 胡莹玮; 花俊文; 张希珂; 郭璐璐; 王攀; 秦培岩
Original assignee: Northwest A&F University
Current assignee: Northwest A&F University
Priority date: 2021-03-10
Filing date: 2021-03-10
Publication date: 2021-06-29
Anticipated expiration: 2041-03-10
Also published as: CN113040172B

Abstract

The invention discloses a reduced graphene oxide-metal/metal oxide functional composite material, and relates to the technical field of antibacterial nano materials. The composite material comprises reduced graphene oxide and a metal or metal oxide; the mass ratio of the reduced graphene oxide to the metal or metal oxide is 1: 3.5 to 4.5; the metal is silver: the metal oxide is zinc oxide or copper oxide. According to the invention, graphene oxide is used as a raw material, and the reduced graphene oxide-metal/metal oxide functional composite material is prepared in situ by a one-step hydrothermal method, so that the dispersibility and the synergistic antibacterial performance of the graphene and the metal or metal oxide in water are improved, the cost is low, the method is simple and convenient, and the inhibition effect on phytophthora sojae is obvious.

Description

Reduced graphene oxide-metal/metal oxide functional composite material, preparation method and application thereof

Technical Field

The invention relates to the technical field of antibacterial nano materials, in particular to a reduced graphene oxide-metal/metal oxide functional composite material, a preparation method and application thereof.

Background

Phytophthora sojae is a semi-autotrophic, syngeneic oomycete with a narrow host range and economic hazards limited to soybeans (Glycine max (L.)). Phytophthora sojae was first reported in 1948 in Indiana, USA as the cause of soybean root rot. Since then, it became an important soybean pathogen in asia, africa, australia, europe and north-south american soybean production areas. It causes seedling blight and root rot of mature plants, has become a limiting factor in the successful production of soybeans, and is estimated to lose about $ 10-20 million worldwide each year. China is the fourth major bean producing country in the world at present, the planting area is wide, and the environmental conditions of various planting areas in the soybean harvesting season are all favorable for the infection of phytophthora sojae zoospores. The evidence of phytophthora sojae has been continuously found in various regions at present, and in order to prevent the economic loss of soybean production, a novel environment-friendly bactericide is hoped to be found to quickly and effectively prevent and treat the soybean, and the actual agricultural problem is solved through a nano scientific technology.

Currently, with the rapid development of nanoscience technology, nanoparticles are receiving much attention for their potential in improving drug delivery, slowing down active ingredient release, and low-concentration antibacterial activity. Particularly, metal and metal oxide NPs have unique physicochemical properties different from those of the same class of macroscopic materials due to their small volume and large surface area. Based on this, metal and metal oxide NPs have been used in various fields, such as catalysis, photonics, biosensors, optoelectronics, and antifungal/antibacterial applications. For example, zinc oxide (ZnO), copper oxide (CuO), and silver (Ag) NPs have been widely reported for plant disease control. They use mechanisms completely different from traditional bactericides and can target a variety of biomolecules to combat strains that have developed resistance. In summary, they can exert antibacterial activity through cell membrane damage, DNA interactions, and Reactive Oxygen Species (ROS) pathways. In addition, zinc and copper are used as trace elements required by plant growth, and have the potential of promoting plant growth and resisting stress in a proper concentration range. However, their antimicrobial properties tend to be reduced or even lost in applications due to the aggregating effect of metal and metal oxide NPs.

Graphene (Graphene) as a two-dimensional (2D) sp²Hybrid carbon structures, which have a hexagonal arrangement structure, have received much attention in many fields due to their excellent physicochemical properties and the like. Researches find that Graphene and Graphene Oxide (Graphene Oxide) and Reduced Graphene Oxide (Reduced Graphene Oxide) which are derivatives of Graphene have the functions of destroying microbial cell membranes and generating a large amount of ROS, so that the Graphene and Graphene Oxide are widely applied to antibacterial application. Although graphene-based materials exhibit antibacterial properties, they also have a strong tendency to agglomerate due to their high surface energy, particularly graphene and reduced graphene oxide.

Disclosure of Invention

The invention aims to solve the defects in the background technology and provides a graphene functional composite material, and preparation and application thereof. The rGO-metal/metal oxide nano composite material is prepared in situ by a one-step hydrothermal method, so that the dispersibility and the synergistic antibacterial performance of graphene and metal or metal oxide in water are improved, the cost is low, the method is simple and convenient, and the inhibition effect on phytophthora sojae is obvious.

The first object of the invention is to provide a reduced graphene oxide-metal/metal oxide functional composite material, which comprises reduced graphene oxide and metal or metal oxide; the mass ratio of the reduced graphene oxide to the metal or metal oxide is 1: 3.5 to 4.5;

the metal is silver: the metal oxide is zinc oxide or copper oxide.

The second purpose of the invention is to provide a preparation method of a reduced graphene oxide-metal/metal oxide functional composite material, which comprises the following steps:

providing a graphene oxide suspension, wherein the concentration of the graphene oxide suspension is 2-2.5 mg/mL;

adding a metal salt compound into the graphene oxide suspension, uniformly mixing, adding a reducing agent, carrying out hydrothermal reaction, and treating after the reaction is finished to obtain a reduced graphene oxide-metal/metal oxide functional composite material;

the metal salt compound is zinc salt, silver salt or copper salt.

Preferably, the reducing agent is sodium hydroxide.

Preferably, the graphene oxide suspension is prepared by uniformly dispersing graphene oxide in an aqueous solvent.

More preferably, the mass ratio of the graphene oxide to the metal salt compound is 1: 5-7.

Preferably, the temperature of the hydrothermal reaction is 85-95 ℃, and the heat preservation time is 3-5 h.

Preferably, the reaction product after the reaction is treated by the following steps:

filtering the reaction product, resuspending with deionized water, washing with water for several times, and freeze-drying at-75-90 deg.C.

Preferably, the zinc salt is zinc chloride or zinc sulfate.

Preferably, the silver salt is silver nitrate.

Preferably, the copper salt is copper chloride or copper sulfate.

The third purpose of the invention is to provide an application of the reduced graphene oxide-metal/metal oxide functional composite material in antibiosis.

Compared with the prior art, the invention has the beneficial effects that:

according to the preparation method of the reduced graphene oxide-metal/metal oxide functional composite material, provided by the invention, graphene oxide is used as a raw material, and the reduced graphene oxide-metal/metal oxide functional composite material is prepared in situ by a one-step hydrothermal method, so that the dispersibility and the synergistic antibacterial performance of the reduced graphene oxide and the metal or metal oxide in water are improved, the cost is low, the method is simple and convenient, and the inhibition effect on phytophthora sojae is obvious.

According to the invention, the graphene-based material is modified by metal and metal oxide NPs, so that the performance of the graphene-based material is enhanced, the dispersibility of the graphene-based material in water is improved, and the graphene-based material is prevented from agglomerating.

The functional composite material obtained by the invention can be used for developing novel environment-friendly nano bactericides and applying the novel environment-friendly nano bactericides to agricultural production. The preparation method has the advantages of environment-friendly and easily-obtained raw materials, low reagent price, simple and easy operation, safety and applicability, and industrial production.

Drawings

FIG. 1 is a Transmission Electron Microscope (TEM) photograph of the functional composite material provided in the example;

wherein, fig. 1a is a TEM photograph of reduced graphene oxide (rGO); FIG. 1b is a TEM photograph of a reduced graphene oxide-zinc oxide functional composite (rGO-ZnO); FIG. 1c is a TEM photograph of a reduced graphene oxide-copper oxide functional composite (rGO-CuO); FIG. 1d is a TEM photograph of a reduced graphene oxide-silver functional composite (rGO-Ag).

FIG. 2 is a Scanning Electron Microscope (SEM) photomicrograph of the functional composite provided in the examples;

wherein, fig. 2a is an SEM photograph of reduced graphene oxide (rGO); FIG. 2b is an SEM photograph of a reduced graphene oxide-zinc oxide functional composite (rGO-ZnO); FIG. 2c is an SEM photograph of a reduced graphene oxide-copper oxide functional composite (rGO-CuO); fig. 2d is an SEM photograph of reduced graphene oxide-silver functional composite (rGO-Ag).

FIG. 3 is an energy spectrum diffraction (EDS) of the functional composite provided in the examples;

wherein, fig. 3a is an EDS diagram of reduced graphene oxide (rGO); FIG. 3b is an EDS diagram of a reduced graphene oxide-zinc oxide functional composite (rGO-ZnO); FIG. 3c is an EDS diagram of a reduced graphene oxide-copper oxide functional composite (rGO-CuO); figure 3d is EDS diagram of reduced graphene oxide-silver functional composite (rGO-Ag).

FIG. 4 is an X-ray diffraction pattern (XRD) of the functional composite provided in the examples;

wherein, fig. 4a is an XRD pattern of Graphene Oxide (GO), reduced graphene oxide (rGO), zinc oxide (ZnO) and reduced graphene oxide-zinc oxide functional composite (rGO-ZnO); FIG. 4b is an XRD plot of Graphene Oxide (GO), reduced graphene oxide (rGO), copper oxide (CuO) and a reduced graphene oxide-copper oxide functional composite (rGO-CuO); fig. 4c is an XRD pattern of Graphene Oxide (GO), reduced graphene oxide (rGO), silver (Ag) and reduced graphene oxide-silver functional composite (rGO-Ag).

FIG. 5 is a Fourier Infrared Spectroscopy (FT-IR) of the functional composite provided in the examples;

wherein, fig. 5a is an FT-IR diagram of reduced graphene oxide (rGO), zinc oxide (ZnO) and a reduced graphene oxide-zinc oxide functional composite (rGO-ZnO); FIG. 5b is a FT-IR plot of reduced graphene oxide (rGO), copper oxide (CuO) and reduced graphene oxide-copper oxide functional composite (rGO-CuO); fig. 5c is an FT-IR diagram of reduced graphene oxide (rGO), silver (Ag) and reduced graphene oxide-silver functional composite (rGO-Ag).

FIG. 6 is an X-ray photoelectron spectroscopy (XPS) of the functional composite provided in the examples;

wherein, fig. 6a is XPS diagram of Graphene Oxide (GO), reduced graphene oxide (rGO), zinc oxide (ZnO) and reduced graphene oxide-zinc oxide functional composite (rGO-ZnO); FIG. 6b is a XPS plot of Graphene Oxide (GO), reduced graphene oxide (rGO), copper oxide (CuO) and reduced graphene oxide-copper oxide functional composite (rGO-CuO); fig. 6c is an XPS plot of Graphene Oxide (GO), reduced graphene oxide (rGO), silver (Ag), and reduced graphene oxide-silver functional composites (rGO-Ag).

FIG. 7 is a graph of the results of experiments on the inhibition of phytophthora sojae hyphae growth by reduced graphene oxide-zinc oxide functional composite (rGO-ZnO) and single ZnO nanomaterial;

wherein, fig. 7a. blank group;

FIG. 7b.0.1, 0.25, 0.5 mg/mLrGO-ZnO;

FIG. 7c.0.1, 0.25, 0.5 mg/mLZnO.

FIG. 8 is a graph of the results of experiments on the inhibition of phytophthora sojae hyphae growth by reduced graphene oxide-copper oxide functional composite (rGO-CuO) and a single CuO nanomaterial;

wherein, fig. 8a. blank group;

FIG. 8b.0.1, 0.25, 0.5 mg/mLrGO-CuO;

FIG. 8c.0.1, 0.25, 0.5 mg/mLCuO.

FIG. 9 is a graph of the results of experiments on the inhibition of phytophthora sojae hyphae growth by reduced graphene oxide-silver functional composites (rGO-Ag) and single Ag nanomaterials;

wherein, fig. 9a. blank group;

FIG. 9b.0.1, 0.25, 0.5 mg/mLrGO-Ag;

FIG. 9c.0.1, 0.25, 0.5mg/ml Ag.

FIG. 10 is a graph of the results of experiments on the inhibition of phytophthora sojae hyphae growth by reduced graphene oxide-copper oxide functional composite (rGO-CuO) and a single CuO nanomaterial;

wherein, fig. 10a. blank group;

FIG. 10b.0.1, 0.25, 0.5 mg/mLrGO-CuO;

FIG. 10c.0.1, 0.25, 0.5 mg/mLCuO.

Detailed Description

In order to make the technical solutions of the present invention better understood and implemented by those skilled in the art, the present invention is further described below with reference to the following specific embodiments and the accompanying drawings, but the embodiments are not meant to limit the present invention.

It should be noted that the experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials used are commercially available, unless otherwise specified.

Example 1

A preparation method of a reduced graphene oxide-zinc oxide functional composite material (rGO-ZnO) comprises the following steps:

adding ZnO: the theoretical calculation of the rGO mass ratio of 4:1 is that 40mL of 2.5mg/mL GO dispersion liquid is added into a 150mL conical flask, and 0.6700g of ZnCl is weighed₂Dissolving in GO dispersion liquid, adding 4mL of 5M NaOH into a new centrifuge tube by a liquid transfer gun, dropwise adding into a conical flask, controlling the dropwise adding time to be 3min, magnetically stirring for 4h at 90 ℃ and 500r/min, transferring a sample into the new centrifuge tube, performing suction filtration by using a 0.2 mu M microporous filter membrane, adding deionized water for resuspension, washing for three times, and performing freeze drying on a final product at-80 ℃ to obtain the reduced graphene oxide-zinc oxide functional composite material (rGO-ZnO).

Example 2

A preparation method of a reduced graphene oxide-copper oxide functional composite material (rGO-CuO) comprises the following steps:

mixing CuO: the theoretical calculation of the rGO mass ratio of 4:1 is that 40mL of 2.5mg/mL GO dispersion liquid is added into a 150mL conical flask, and 0.8573g of CuCl is weighed₂·2H₂Dissolving O in GO dispersion liquid, adding 4mL of 5M NaOH into a new centrifugal tube by a pipette gun, dropwise adding into a conical flask, controlling the dropwise adding time to be 3min, magnetically stirring for 4h at 90 ℃ and 500r/min, transferring a sample into the new centrifugal tube, performing suction filtration by using a 0.2 mu M microporous filter membrane, adding deionized water for resuspension, washing for three times, and performing freeze drying on a final product at-80 ℃ to obtain the reduced graphene oxide-copper oxide functional composite material (rGO-CuO).

Example 3

A preparation method of a reduced graphene oxide-silver functional composite material (rGO-Ag) comprises the following steps:

adding Ag: theoretical calculation of the rGO mass ratio of 4:1, 40mL of 2.5mg/mL GO dispersion liquid is added into a 150mL conical flask, and 0.6300g of AgNO is weighed₃Dissolving in GO dispersion, adding 4mL of 5M NaOH into a new centrifuge tube by a pipette, dropwise adding into a conical flask, controlling the dropwise adding time to be 3min, magnetically stirring for 4h at 90 ℃ and 500r/min, transferring the sample into the new centrifuge tube, performing suction filtration by a 0.2-micrometer microporous filter membrane, adding deionized water for resuspension, washing for three times, and freeze-drying the final product at-80 ℃ to obtain the reduced graphene oxide-silver oxideFunctional composites (rGO-Ag).

Example 4

adding ZnO: the theoretical calculation of the rGO mass ratio of 4:1 is that 40mL of 2.5mg/mL GO dispersion liquid is added into a 150mL conical flask, 0.6700g of zinc sulfate is weighed and dissolved in the GO dispersion liquid, 4mL of 5M NaOH is added into a new centrifuge tube by a pipette, one drop is added into the conical flask, the dropping time is controlled to be 3min, the sample is transferred into the new centrifuge tube after being magnetically stirred for 4h at 90 ℃ and 500r/min, a 0.2 mu m microporous filter membrane is used for suction filtration, deionized water is added for resuspension and washing for three times, and the final product is frozen and dried at minus 80 ℃ to obtain the reduced graphene oxide-zinc oxide functional composite material (rGO-ZnO).

In order to illustrate the performance of the functional composite materials prepared in examples 1 to 3, the reduced graphene oxide functional composite materials prepared in examples 1 to 3 are subjected to correlation performance detection, and in particular, the morphological characteristics of the rGO, rGO-ZnO, rGO-CuO and rGO-Ag nanocomposite materials are characterized by a transmission electron microscope (TEM, JEM-2100Plus) and a scanning electron microscope (SEM, S-4800) and subjected to element analysis by means of an accessory X-ray spectrometer of the scanning electron microscope; functional group analysis and phase analysis of the material were performed using an X-ray diffractometer (D8ADVANCEA25), a Fourier Infrared spectrometer (Nicolet iS10), and X-ray photoelectron spectroscopy (ThermoFisherescalab 250Xi), as shown in FIGS. 1-6.

The preparation method of the reduced graphene oxide (rGO) comprises the following steps:

firstly, accurately weighing 0.4g of GO in a 200mL beaker, adding 160mL of deionized water, performing ultrasonic treatment for 30min (500W, 4s on and 6s off) to form 2.5mg/mL GO dispersion, adding 40mL into a 150mL conical flask, preparing 10mL of 5M NaOH solution in advance, adding 2mL of the solution into the conical flask by a pipette drop, controlling the dropping time to be 1.5min, magnetically stirring for 4h at 90 ℃ and 500r/min, transferring a sample into a new centrifuge tube, performing suction filtration by using a 0.2 mu m microporous filter membrane, adding deionized water for resuspension, washing for three times, and freeze-drying the final product at-80 ℃.

As can be seen from fig. 1, fig. 1a clearly shows the typical folded structure of graphene sheet material, fig. 1b shows that a large number of zinc oxide nanoparticles (5-50nm) are loaded on the reduced graphene oxide sheet layer, fig. 1c shows that typical rod-shaped copper oxide nanoparticles (5-100nm) are loaded on the reduced graphene oxide sheet layer, and fig. 1c shows that spherical silver nanoparticles (5-50nm) are loaded on the reduced graphene oxide sheet layer having the folded structure.

As can be seen from fig. 2, the typical folded structure of the reduced graphene oxide can be more clearly observed through a scanning electron microscope, and as can be seen from fig. 2b, 2c, and 2d, the spindle-shaped zinc oxide, the rod-shaped copper oxide, and the spherical silver nanoparticles are assembled with the reduced graphene oxide sheet layer.

From fig. 3, it can be seen that the peak C, O in fig. 3a is mainly seen by analyzing the elemental composition of the sample through EDS, which illustrates that the reduced graphene oxide surface still has oxygen-containing functional groups, while in fig. 3b, 3c, and 3d, respectively, the presence of the elements zinc, copper, and silver corresponding to the metal nanoparticles further demonstrates that the synthesized composite material is zinc oxide, copper oxide, and silver nanoparticles.

As can be seen from fig. 4, XRD analysis of Graphene Oxide (GO), reduced graphene oxide (rGO), and reduced graphene oxide-metal/metal oxide nanocomposites confirmed the formation of ZnO NPs, CuONPs, AgNPs crystals in the functional nanocomposite. As shown in fig. 4a to 4c, there is a diffraction peak around 9.27 ° in the spectrum of the graphene oxide, which is a characteristic peak of the graphene oxide, and this peak does not appear in the spectra of the reduced graphene oxide (rGO) and the reduced graphene oxide-metal/metal oxide functional composite material, which indicates that the graphene oxide is converted into the reduced graphene oxide (rGO) by deoxidation. The rGO-ZnO nanocomposite has 11 new characteristic diffraction peaks in the spectrum, which are respectively located at ZnO (2 θ ═ 31.67 °,34.31 °, 36.16 °,47.39 °,56.49 °, 62.74 °, 66.20 °, 67.85 °, 69.01 °, 72.45 °, 76.91 °), the rGO-CuO nanocomposite has 11 new characteristic diffraction peaks in the spectrum, which are respectively located at CuO (2 θ ═ 32.46 °, 35.49 °,38.66 °,48.72 °,53.38 °, 58.20 °, 61.50 °, 66.24 °, 68.07 °, 72.33 °, 75.12 °), and the rGO-Ag nanocomposite has 4 new characteristic diffraction peaks in the spectrum, which are respectively located at Ag (2 θ ═ 38.11 °,44.30 °,64.50 °,77.41 °), which indicates the synthesis of rGO-ZnO, rGO-CuO, and rGO-Ag nanocomposites.

As can be seen from FIGS. 5a to 5c, the reduced graphene oxide shows several characteristic peaks at a wave number of 3413 cm^-1And 1390cm^-1And (4) an OH peak. 1583cm^-1And 1053cm of carbon-carbon double bond (C ═ C)^-1Epoxy group (C-O). While rGO-ZnO and rGO-CuO are in 430cm^-1And 509cm^-1Corresponding Zn-O and Cu-O peaks appear.

As can be seen from fig. 6, when XPS was used to measure the chemical composition of graphene oxide, reduced graphene oxide, and reduced graphene oxide-metal/metal oxide nanocomposite, the C peak at 284.81eV was increased and the O peak at 532.35eV was decreased in the reduced graphene oxide compared to graphene oxide, indicating that graphene oxide underwent deoxidation and the reduced graphene oxide-metal/metal oxide nanocomposite exhibited Zn, Cu, and Ag element peaks at 1022eV, 934eV, and 369eV, respectively.

In order to further illustrate the antibacterial performance of the functional composite material provided by the invention, the functional composite material prepared in the embodiments 1-3 is subjected to a phytophthora sojae bacteriostasis test. See FIGS. 7-10.

And (3) carrying out soybean phytophthora bacteriostasis test: culturing phytophthora sojae with 10% V8 fruit and vegetable juice culture medium, beating phytophthora sojae hypha cakes with 5mm edges and growing for 5d, transferring the phytophthora sojae hypha cakes to the rGO-ZnO, rGO-CuO and rGO-Ag functional composite materials provided in examples 1-3 on culture medium plates treated in different concentrations, culturing for 5d at 28 ℃ in the dark, measuring radial growth of the hypha, and calculating the radial growth inhibition rate; meanwhile, single ZnO, CuO and Ag nano materials are used as a comparison test, and equal volume of deionized water is added as a blank control group. The experiment is carried out in a growth inhibition experiment in an artificial incubator under a dark condition, 8 pieces of the experiment are processed in parallel, after the experiment is carried out for 5 days, the radial growth of the phytophthora sojae is measured, the growth inhibition rate is calculated, the experiment process is shown in figures 7-9, and the result is shown in table 1. Among them, ZnO, CuO and Ag nanomaterials are all purchased from Shanghai Aladdin reagent company.

TABLE 1 antibacterial test design and growth inhibition

wherein, fig. 7a. blank group;

FIG. 7b.0.1, 0.25, 0.5 mg/mLrGO-ZnO;

FIG. 7c.0.1, 0.25, 0.5 mg/mLZnO.

wherein, fig. 8a. blank group;

FIG. 8b.0.1, 0.25, 0.5 mg/mLrGO-CuO;

FIG. 8c.0.1, 0.25, 0.5 mg/mLCuO.

wherein, fig. 9a. blank group;

FIG. 9b.0.1, 0.25, 0.5 mg/mLrGO-Ag;

FIG. 9c.0.1, 0.25, 0.5mg/ml Ag.

As can be seen from Table 1 and FIGS. 7 to 9, hypha growth inhibition experiments show that 0.1, 0.25 and 0.5mg/mL of rGO-ZnO and ZnO have significant effects on the growth of phytophthora sojae compared with a control group, and the rGO-ZnO has stronger inhibition effect on the growth of phytophthora sojae compared with ZnO. Compared with a control group, rGO-CuO and CuO of 0.1, 0.25 and 0.5mg/mL completely inhibit the growth of phytophthora sojae. Compared with a control group, rGO-Ag with the concentration of 0.1, 0.25 and 0.5mg/mL has certain influence on the growth of phytophthora sojae, and Ag has little influence on the growth of phytophthora sojae.

In view of the analysis, the inhibition effect of the three functional composite materials on phytophthora sojae is obvious, the difference between rGO-ZnO and ZnO is not obvious, and the Ag nano material is easy to agglomerate, so that the antibacterial activity cannot be well reflected; the antibacterial effect of the two materials of rGO-CuO and CuO is most obvious, and the growth of phytophthora sojae is completely inhibited under the same concentration, so that the further antibacterial effect analysis of the two materials of rGO-CuO and CuO shows that an inhibition test is carried out on the two materials and the concentration is reduced, the test process is shown in figure 10, and the result is shown in table 2.

TABLE 2 rGO-CuO and CuO bacteriostatic test design and growth inhibition

wherein, fig. 10a. blank group;

FIG. 10b.0.01, 0.025, 0.05 mg/mLrGO-CuO;

FIG. 10c.0.01, 0.025, 0.05 mg/mLCuO.

As can be seen from table 2, after ten times of concentration reduction again, phytophthora sojae starts to grow, but the antibacterial effect is still more significant compared to the other two materials, and it can be seen that the toxic effect of the Cu-based material on phytophthora sojae is significantly stronger. The rGO-CuO nano composite material is more excellent than a single CuO material, which shows that the nano composite material obtains a good synergistic effect, and from the overall result, the invention successfully synthesizes three nano composite materials for preventing and treating phytophthora sojae, wherein the rGO-CuO has the most obvious effect, and the nano composite material shows high-efficiency antibacterial property at low concentration, and is hopeful to be further developed into a nano environment-friendly bactericide. As can be seen from fig. 10, the concentrations of rGO-CuO and CuO were further reduced, and 0.01, 0.025, and 0.05mg/mL of rGO-CuO and CuO had significant effects on the growth of phytophthora sojae, whereas the inhibition ratio of rGO-CuO was higher than that of CuO.

In conclusion, according to the preparation method of the reduced graphene oxide-metal/metal oxide functional composite material provided by the invention, graphene oxide is used as a raw material, the reduced graphene oxide-metal/metal oxide functional composite material is prepared in situ by a one-step hydrothermal method, the dispersibility and the synergistic antibacterial performance of the reduced graphene oxide and the metal or metal oxide in water are improved, the cost is low, the method is simple and convenient, and the inhibition effect on phytophthora sojae is obvious.

The present invention describes preferred embodiments and effects thereof. Additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

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

Claims

1. A reduced graphene oxide-metal/metal oxide functional composite material is characterized in that the composite material comprises reduced graphene oxide and metal or metal oxide; the mass ratio of the reduced graphene oxide to the metal or metal oxide is 1: 3.5 to 4.5;

the metal is silver: the metal oxide is zinc oxide or copper oxide.

2. The preparation method of the reduced graphene oxide-metal/metal oxide functional composite material according to claim 1, comprising the following steps:

the metal salt compound is zinc salt, silver salt or copper salt.

3. The method of claim 2, wherein the reducing agent is sodium hydroxide.

4. The method of claim 2, wherein the graphene oxide suspension is prepared by uniformly dispersing graphene oxide in an aqueous solvent.

5. The preparation method of the reduced graphene oxide-metal/metal oxide functional composite material according to claim 2, wherein the temperature of the hydrothermal reaction is 85-95 ℃, and the heat preservation time is 3-5 h.

6. The method for preparing the reduced graphene oxide-metal/metal oxide functional composite material according to claim 2, wherein a reaction product after the reaction is treated by the following steps:

7. The method for preparing a reduced graphene oxide-metal/metal oxide functional composite according to claim 2, wherein the zinc salt is zinc chloride or zinc sulfate.

8. The method for preparing a reduced graphene oxide-metal/metal oxide functional composite according to claim 2, wherein the silver salt is silver nitrate.

9. The method of claim 2, wherein the copper salt is cupric chloride or cupric sulfate.

10. The use of the reduced graphene oxide-metal/metal oxide functional composite of claim 1 for antimicrobial applications.