CN104673185A - Method for preparing reduced graphene oxide/CoFe2O4/Ag composite wave-absorbing material - Google Patents

Abstract

The invention provides a method for preparing a reduced graphene oxide/CoFe2O4/Ag composite wave-absorbing material. According to the method, RGO/CoFe2O4 is prepared by use of a hydrothermal method, and then the RGO/CoFe2O4/Ag ternary composite wave-absorbing material is prepared by use of a wet chemical method. The method is characterized in that no any surfactant is needed and also no insert gas such as nitrogen is needed for protection; the preparation process is simple and the preparation conditions are easy to implement.

Description

One prepares redox graphene/CoFe 2o 4the method of/Ag composite wave-suction material

Technical field

The present invention relates to a kind of method preparing tri compound microwave absorbing material.

Background technology

It is high that ferrite has wave absorbing efficiency, bandwidth, the advantage that cost is low, it is radio-radar absorber practical and the most frequently used the earliest, large in order to overcome ferrite density, the deficiencies such as hot properties difference, strengthen its absorbing property, domestic and international investigator is at trial development of new Ferrite Material, one of them important directions is exactly be the carbonaceous material with single layer structure of the tightly packed formation of carbon atom by the absorbing material Graphene that compound obtains excellent performance, excellent performance, its two-dimensional sheet structure is conducive to electromagnetic absorption, take Graphene as matrix load iron oxysome, quality can be obtained light, inhale the composite wave-suction material of ripple bandwidth.Copper race metal A g is excellent electro-conductive material, and under electromagnetic effect, surface field amount is maximum, more gos deep into its conductor, field amount less (this phenomenon is also referred to as skin effect).Utilize the skin effect of copper race metal that radar wave can be stoped to penetrate good conductor to prepare absorbing material.

Document " " Materials Letters " 91 (2013) pp.209-212, " discloses a kind of high temperature reduction that adopts and prepares RGO/Fe ₃o ₄the method of matrix material.Concrete grammar is by Fe (NO ₃) ₃9H ₂o and redox graphene (RGO) ultrasonic dissolution are after ethylene glycol, and add Surfactant SDS (SDS) and sodium dodecyl benzenylsulfonate (SDBS), mixture stirs 1h at 60 DEG C; Then, after adding the NaOH aqueous solution in mixing solutions, continue to stir 2h; It is 7 that the mixture deionized water obtained is washed till pH, puts into 60 DEG C of dry 12h of loft drier; The powder obtained is put in tube furnace, under argon shield, be slowly heated to 450 DEG C, cools the temperature to 355 DEG C, pass into hydrogen and argon gas gas mixture after keeping 2h, and keep 30min, the powder obtained is RGO/Fe ₃o ₄matrix material.Through electromagnetic performance test, when this thickness of composite material is 2mm, at 14.3-18GHz reflection loss lower than-10dB, reach maximum absorption when 17.3GHz for-22.2dB.

In document, the preparation method of matrix material mainly has the following disadvantages: need to add and show and promoting agent SDS and SDBS; need to use nitrogen to protect; need to use hydrogen and argon gas mixed gas to reduce; need hot environment; preparation process is complicated, is difficult to realize scale production, and the matrix material of preparation absorbs and mainly appears at high frequency; and less to absorption of electromagnetic wave, poor performance.

Summary of the invention

In order to overcome high temperature reduction legal system for RGO/Fe ₃o ₄the deficiencies such as matrix material condition is harsh, process is complicated, poor performance, the present invention proposes a kind of novel RGO/CoFe ₂o ₄/ Ag tri compound absorbing material preparation method.

To achieve these goals, technical scheme of the present invention is as follows: one prepares redox graphene/CoFe ₂o ₄the method of/Ag composite wave-suction material, first adopts hydrothermal method to prepare RGO/CoFe ₂o ₄, then adopt wet chemical method to prepare RGO/CoFe ₂o ₄ag tri compound absorbing material.Specifically the steps include:

A, configuration concentration are GO (graphene oxide) aqueous solution of 0.2-2mg/ml, and the NaOH aqueous solution of configuration 0.5-5mol/L is for subsequent use;

B, according to mass ratio GO: Co (NO ₃) ₂6H ₂o: Fe (NO ₃) ₃9H ₂o=I: x: 2.76x, wherein x=(0.1-10), takes Co (NO ₃) ₂6H ₂o and Fe (NO ₃) ₃9H ₂o, joins in a certain amount of GO aqueous solution, drips NaOH solution and regulate pH of mixed to be 9-12 after stirring 30min;

C, above-mentioned mixed solution joined with tetrafluoroethylene be liner water heating kettle in, at 150-180 DEG C, react 9-15h;

D, gained precipitate with deionized water and dehydrated alcohol alternately wash to pH=7, the RGO/CoFe obtained ₂o ₄precipitation is scattered in 100-200ml deionized water, according to mass ratio GO: AgNO ₃=1: 0.3-3 takes AgNO ₃, join in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄=1: (3-30), takes NaBH ₄be dissolved in 20-100ml water, then instill in mixed solution, at 40-100 DEG C, heat 0.5-2h;

C, use deionized water and dehydrated alcohol alternately washing to pH=7, utilize magnetic resolution, black precipitate that centrifugal or suction filtration obtains, adopt 40-80 DEG C of vacuum-drying, the black powder obtained is RGO/CoFe ₂o ₄/ Ag trielement composite material.

The present invention has the following advantages:

1, the present invention is by hydrothermal method and wet chemical method two step synthesizing new RGO/CoFe ₂o ₄/ Ag trielement composite material, without the need to adding any tensio-active agent, without the need to adopting the protection of inert gas such as chlorine, preparation process is simple, and preparation condition easily realizes;

2, the RGO/CoFe that system of the present invention is each ₂o ₄/ Ag trielement composite material absorbing property is good, maximum suction below Bo Keda-55dB, inhales ripple bandwidth, effectively absorbs and can reach 4.2GHz, and can by regulating RGO, CoFe ₂o ₄realizing effective absorption of different-waveband with the ratio of Ag and the thickness of matrix material, is a kind of absorbing material of excellent performance.

Accompanying drawing explanation

Fig. 1:: the X ray diffracting spectrum (XRD) of product in embodiment 1-3.

Fig. 2: product RGO/CoFe in embodiment 1 ₂o ₄the transmission electron microscope picture (TEM) of/Ag matrix material.

Fig. 3: product RGO/CoFe in embodiment 1 ₂o ₄the high power transmission electron microscope picture (HRTEM) of/Ag matrix material and partial enlarged drawing.

Fig. 4: product RGO/CoFe in embodiment 1 ₂o ₄the absorbing property figure of/Ag matrix material.

Embodiment

Illustrate that elbow the present invention is described further below in conjunction with accompanying drawing.

Embodiment 1

1, compound concentration is the GO water Ji liquid of 0.67mg/ml, and the NaOH aqueous solution of preparation 1mol/L is for subsequent use;

2, according to mass ratio GO: Co (NO ₃) ₂6H ₂o: Fe (N0 ₃) ₃9H ₂o=1: 1.24: 3.42, take 124mg Co (NO ₃) ₂6H ₂o and 342mgFe (NO ₃) ₃9H ₂o, joins in the 150mlGO aqueous solution, after stirring 30min, drips NaOH solution and regulates pH of mixed to be 11;

3, above-mentioned mixed solution is joined with tetrafluoroethylene be liner water heating kettle in, react 12h at 180 DEG C;

4, gained precipitate with deionized water and dehydrated alcohol alternately wash to pH=7, the RGO/CoFe obtained ₂o ₄precipitation is scattered in 150ml deionized water, according to mass ratio GO: AgNO ₃take 63mg AgNO at=1: 0.63 ₃, add in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄=1: 5, take 500mgNaBH ₄help in 20ml water, in instillation mixed solution, at 80 DEG C, heat 2h;

5, use deionized water and dehydrated alcohol alternately washing to pH=7, utilize magnetic resolution, black precipitate that centrifugal or suction filtration obtains, adopts 60 DEG C of vacuum-dryings, the toner end of shining obtained is RGO/CoFe ₂o ₄/ Ag trielement composite material.

The XRD spectra of embodiment 1 product is shown in Fig. 1, and in figure, the diffraction peak-to-peak of 24 degree can belong to RGO, and all the other diffraction peaks all can belong to CoFe ₂o ₄with Ag two kinds of crystal, there is no the appearance of impurity peaks, prove successfully to have prepared RGO/CoFe by aforesaid method ₂o ₄/ Ag trielement composite material.Be 1: 1 Homogeneous phase mixing by the powdered product in embodiment 1 and solid paraffin according to mass ratio, in particular manufacturing craft, be pressed into external diameter 7.00mm, internal diameter 3.04mm, coaxial sample that thickness is about 3mm, be that HP8720ES vector network analyzer tests its absorbing property by model, test frequency is 2-18GHz.As shown in Figure 4, the matching thickness of this sample is 2.1mm to its absorbing property, reaches maximum absorption for-56.4dB when 13.1GHz, and inhale ripple at 11.1-15.1GHz and reach below-10dB, effectively absorbing width is 4.0GHz; Thickness effectively absorbs width and reaches maximum when 2.0mm, absorb at 11.7-15.9GHz and reach below-10dB, effectively absorbing width is 4.2GHz.

TEM figure and the HRTEM figure of embodiment 1 product as Figure 2-3.From Fig. 2 and Fig. 3 (a), CoFe ₂o ₄with Ag load at graphenic surface; Clearly CoFe can be found out by Fig. 3 (b) ₂o ₄the lattice fringe of nano particle (311), Fig. 3 (c) clearly can find out the lattice fringe of Ag nano particle (111) and (200), further illustrates the present invention and obtains RGO/CoFe ₂o ₄/ Ag trielement composite material.

Embodiment 2

1, compound concentration is the GO aqueous solution of 0.67mg/ml, and the NaOH aqueous solution of preparation 1mol/L is for subsequent use;

2, according to mass ratio GO: Co (NO ₃) ₂6H ₂o: Fe (NO ₃) 3 ₉h ₂o=1: 1.24: 3.42, take 124mgCo(NO ₃) ₂6H ₂o and 342mgFe (N0 ₃) 39H ₂o, joins in the 150mlGO aqueous solution, after stirring 30min, drips NaOH solution and regulates pH of mixed to be 11;

3, above-mentioned mixed solution is joined with tetrafluoroethylene be liner water heating kettle in, react 12h at 180 DEG C;

4, gained precipitate with deionized water and dehydrated alcohol alternately wash to pH=7, the RGO/CoFe obtained ₂o ₄precipitation is scattered in 150ml deionized water, according to mass ratio GO: AgNO ₃take 95mg AgNO at=1: 0.95 ₃, add above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄=1: 5, take 500mgNaBH ₄be dissolved in 20ml water, in instillation mixed solution, at 80 DEG C, heat 2h;

5, use deionized water and dehydrated alcohol alternately washing to pH=7, utilize magnetic resolution, black precipitate that centrifugal or suction filtration obtains, adopt 60 DEG C of vacuum-dryings, the black powder obtained is RGO/CoFe ₂o ₄/ Ag trielement composite material.

The XRD spectra of embodiment 2 product is shown in Fig. 1, and in figure, the diffraction peak-to-peak of 24 degree can be returned and be bent in RGO, and all the other diffraction peaks all can belong to CoFe ₂o ₄with Ag two kinds of crystal, there is no the appearance of impurity peaks, prove successfully to have prepared RGO/CoFe by aforesaid method ₂o ₄/ Ag trielement composite material.Be that 1: 1 Homogeneous phase mixing is pressed into coaxial sample by the powdered product in embodiment 2 and solid paraffin mass ratio, and test its absorbing property (method is with embodiment 1).The matching thickness of this sample is 5.4mm, reaches maximum absorption for-45.1dB when 4.7GHz, and inhale ripple at 4.0-5.6GHz and 14.0-15.3GHz and reach below-10dB, effectively absorbing width is 2.8GHz.

Embodiment 3

1, compound concentration is the GO aqueous solution of 0.67mg/ml, and the NaOH aqueous solution of preparation 1mol/L is for subsequent use;

2, according to mass ratio GO: Co (NO ₃) ₂6H ₂o: Fe (NO ₃) ₃9H ₂o=1: 1.24: 3.42, take 124mg Co (NO ₃) ₂6H ₂o and 342mg Fe (NO ₃) ₃9H ₂o, joins in the 150ml GO aqueous solution, after stirring 30min, drips NaOH solution and regulates pH of mixed to be 11;

3, above-mentioned mixed solution is joined with tetrafluoroethylene be liner water heating kettle in, react 12h at 180 DEG C;

4, gained precipitate with deionized water and dehydrated alcohol alternately wash to pH=7, the RGO/CoFe obtained ₂o ₄precipitation is scattered in 150ml deionized water, according to mass ratio GO: AgNO ₃take 126mg AgNO at=1: 1.26 ₃, add in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄=1: 5, take 500mg NaBH ₄be dissolved in 20ml water, in instillation mixed solution, at 80 DEG C, heat 2h;

5 use deionized waters and dehydrated alcohol alternately washing to pH=7, utilize magnetic resolution, black precipitate that centrifugal or suction filtration reed obtains, adopt 60 DEG C of vacuum-dryings, the black powder obtained is RGO/CoFe ₂o ₄/ Ag trielement composite material.

The XRD spectra of embodiment 3 product is shown in Fig. 1, and in figure, the diffraction peak-to-peak of 24 degree can belong to RGO, and all the other diffraction peaks all can belong to CoFe ₂o ₄with Ag two kinds of crystal, there is no the appearance of impurity peaks, prove successfully to have prepared RGO/CoFe by aforesaid method ₂o ₄/ Ag trielement composite material.Be that 1: 1 Homogeneous phase mixing is pressed into coaxial sample by the powdered product in embodiment 3 and solid paraffin mass ratio, and test its absorbing property (method is with embodiment 1).The matching thickness of this sample is 4.7mm, reaches maximum absorption for-38.2dB when 5.5GHz, and inhale ripple at 4.6-6.4GHz and 16.2-17.7GHz and reach below-10dB, effectively absorbing width is 3.5GHz.

Claims (1)

1. one kind prepare reduction-oxidation graphite rare/CoFe ₂o ₄the method of/Ag composite wave-suction material, the steps include:

A, compound concentration are GO (graphene oxide) aqueous solution of 0.2-2mg/ml, and the NaOH aqueous solution of preparation 0.5-5mol/L is for subsequent use;

B, according to mass ratio GO: Co (NO ₃) ₂6H ₂o: Fe (NO ₃) ₃9H ₂o=1: x: 2.76x, wherein x=(0.1-10), takes Co (NO ₃) ₂6H ₂o and Fe (NO ₃) ₃9H ₂o, joins in a certain amount of GO aqueous solution, drips NaOH solution and regulate pH of mixed to be 9-12 after stirring 30min;

C, above-mentioned mixed solution joined with tetrafluoroethylene be liner water heating kettle in, at 150-180 DEG C, react 9-15h;

D, gained precipitate with deionized water and dehydrated alcohol alternately wash to pH=7, the RGO/CoFe obtained ₂o ₄precipitation is scattered in 100-200ml deionized water, according to mass ratio GO: AgNO ₃=1: 0.3-3 takes AgNO ₃, join in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄=1: (3-30), takes NaBH ₄be dissolved in 20-100ml water, then instill in mixed solution, at 40-100 DEG C, heat 0.5-2h;

E, use deionized water and dehydrated alcohol alternately washing to pH=7, utilize magnetic resolution, black precipitate that centrifugal or suction filtration obtains, adopt 40-80 DEG C of vacuum-drying, the black powder obtained is RGO/CoFe ₂o ₄/ Ag trielement composite material.