CN103305185B - Method for preparing reduced-oxidized graphene/Fe3O4/Ag nano composite wave-absorbing material - Google Patents

Abstract

The invention relates to a method for preparing a reduced-oxidized graphene/Fe3O4/Ag nano composite wave-absorbing material. The method comprises the following steps: preparing GO/Fe3O4 by using a simplified coprecipitation method, and preparing the RGO/Fe3O4/Ag ternary composite material by employing a wet chemical reducing method. The preparation method is simple and rapid, large-scale production can be realized, the prepared composite material is good in wave-absorbing performance, and different wave bands can be effectively absorbed by adjusting the ratio of RGO to Fe3O4 to Ag, the amount of the reducing agent and the thickness of the composite material.

Description

Redox graphene/Fe 3o 4the preparation method of the nano combined absorbing material of/Ag

Technical field

The invention belongs to the preparation method of tri compound microwave absorbing material, be specifically related to a kind of redox graphene/Fe ₃o ₄the preparation method of the nano combined absorbing material of/Ag.

Background technology

Ferrite has advantages of that wave absorbing efficiency is high, bandwidth, cost are low, is practical and the most frequently used the earliest radio-radar absorber, but because it exists the shortcomings such as density is excessive, high-temperature behavior is poor, has limited its widespread use.In recent years, many domestic and international investigators attempt by ferrite and carbon-based material is compound obtains that density is little, the absorbing material of excellent performance.Graphene is the carbonaceous material with single layer structure of the tightly packed formation of carbon atom, excellent performance, and its two-dimensional sheet structure is conducive to electromagnetic absorption, adopts Fe ₃o ₄with the common grapheme modified matrix of Ag, can obtain the composite wave-suction material that quality is light, inhale ripple bandwidth.

Document " " Materials Letters " 91 (2013) pp.209 – 212, " discloses a kind of employing high temperature reduction and has prepared RGO-Fe ₃o ₄the method of matrix material.Concrete grammar is by Fe ³⁺with redox graphene (RGO) ultrasonic dissolution is in ethylene glycol, adds two kinds of Surfactant SDSs (SDS) and sodium dodecyl benzenylsulfonate (SDBS), mixture stirs 1h at 60 DEG C; In mixing solutions, add the NaOH aqueous solution, continue to stir 2h; It is 7 that the mixture obtaining is washed till to pH with deionized water, puts into the dry 12h of 60 DEG C of loft drier; The powder obtaining is put in tube furnace, is slowly heated to 450 DEG C under argon shield, keeps cooling the temperature to 350 DEG C after 2h, passes into hydrogen and argon gas gas mixture, keeps 30min, and the powder obtaining is RGO-Fe ₃o ₄matrix material.Through electromagnetic performance test, when this thickness of composite material is 2mm, lower than-10dB, in the time of 17.3GHz, reach maximum absorption for-22.2dB at 14.3-18GHz reflection loss.

Described in document, the preparation method of matrix material mainly has the following disadvantages: need to add surfactant SDS and SDBS; need to use nitrogen protection; need to use hydrogen and argon gas mixed gas to reduce; need hot environment, preparation time long (only recombination process just reaches 26h), preparation process complexity; be difficult to realize scale production; the matrix material of preparation is inhaled ripple and is mainly appeared at high frequency, and less to absorption of electromagnetic wave, poor performance.

Summary of the invention

The technical problem solving

For fear of the deficiencies in the prior art part, the present invention proposes a kind of redox graphene/Fe ₃o ₄the preparation method of the nano combined absorbing material of/Ag, overcomes high temperature reduction legal system for RGO-Fe ₃o ₄the deficiency of scale operation, poor performance is grown, is difficult to matrix material preparation condition harshness, process complexity, time.

Technical scheme

A kind of redox graphene/Fe ₃o ₄the preparation method of the nano combined absorbing material of/Ag, is characterized in that step is as follows:

Step 1: the GO graphite oxide aqueous solution that compound concentration is 0.2-2mg/ml, the NaOH aqueous solution of preparation 0.5-5mol/L;

Step 2: according to mass ratio GO: FeCl ₂4H ₂o: FeCl ₃6H ₂o=1: x: (0.8-1.8) x, wherein x=(0.1-10), takes FeCl ₂4H ₂o and FeCl ₃6H ₂o, then joins in GO graphite oxide aqueous solution, and heating in water bath is to 30-50 DEG C of maintenance 10min, and dripping NaOH aqueous solution adjusting pH of mixed is 9-12, and above-mentioned mixed solution heats 2-3h and forms black precipitate at 60-80 DEG C;

Step 3: be dissolved in 100-400ml deionized water after the black precipitate that obtains is adopted to centrifuge washing mode deionized water wash 3-5 time, according to mass ratio GO: AgNO ₃=1:(0.1-5), then with AgNO ₃after mixing, stir 20min and obtain mixed solution; Again according to mass ratio GO: NaBH ₄=1: (5-30), take NaBH ₄be dissolved in 50-200ml water, and splash in mixed solution, at 20-100 DEG C, heat 0.5-2h;

Step 4: product that step 3 is obtained uses deionized water and dehydrated alcohol alternately to wash to pH=7, utilizes magnetic resolution, the black precipitate that centrifugal or suction filtration obtains, then to adopt the black powder that 40-80 DEG C of vacuum-drying obtains be redox graphene/Fe ₃o ₄the nano combined absorbing material of/Ag.

Beneficial effect

A kind of redox graphene/Fe that the present invention proposes ₃o ₄the preparation method of the nano combined absorbing material of/Ag, adopts the coprecipitation method of simplifying to make GO/Fe ₃o ₄, then adopt wet-chemical reduction method to make RGO/Fe ₃o ₄/ Ag trielement composite material, preparation method is simple, quick, can realize scale production, and the Radar Absorbing Properties of Composites making is good, can be by regulating RGO, Fe ₃o ₄realize effective absorption of different-waveband with ratio, the consumption of reductive agent and the thickness of matrix material of Ag.

The present invention has following beneficial effect:

1, the present invention has synthesized RGO/Fe by coprecipitation method and the wet chemical method simplified ₃o ₄/ Ag trielement composite material, without adding any tensio-active agent, without adopting the protection of inert gas such as nitrogen, without heat, preparation condition is easily realized;

2, preparation process of the present invention is simple, consuming time shorter, and recombination process only needs 6-12h, conveniently accomplishes scale production;

3, the RGO/Fe that prepared by the present invention ₃o ₄/ Ag trielement composite material wave absorbing efficiency is high, suction ripple bandwidth, and the maximum Bo Keda-58dB that inhales more than effectively absorption (being less than-10dB) can reach 4GHz, and can pass through to regulate RGO, Fe ₃o 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.

Brief description of the drawings

Fig. 1 is the XRD spectra of three kinds of products preparing in embodiment of the present invention 1-3;

Fig. 2 is the product RGO/Fe of preparation in embodiment 2 ₃o ₄the TEM figure of/Ag matrix material;

Fig. 3 is the product RGO/Fe of preparation in embodiment 2 ₃o ₄the HRTEM figure of/Ag matrix material;

Fig. 4 is the product RGO/Fe of preparation in embodiment 1 ₃o ₄the absorbing property figure of/Ag matrix material;

Fig. 5 is the product RGO/Fe of preparation in embodiment 2 ₃o ₄the absorbing property figure of/Ag matrix material;

Fig. 6 is the product RGO/Fe of preparation in embodiment 3 ₃o ₄the absorbing property figure of/Ag matrix material.

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

Embodiment 1

1, the GO aqueous solution that compound concentration is 0.5mg/ml, the NaOH aqueous solution of preparation 1mol/L is for subsequent use;

2, according to mass ratio GO:FeCl ₂4H ₂o:FeCl ₃6H ₂o=1:2.58:3.52 takes 258mg FeCl ₂4H ₂o and 352mg FeCl ₃6H ₂o, joins in the 200ml GO aqueous solution, and heating in water bath to 50 DEG C keeps 10min, and dripping NaOH solution adjusting pH of mixed is 11, and mixed solution heats 3h at 70 DEG C;

3, be dissolved in 200ml deionized water after the black precipitate that obtains being adopted to centrifuge washing mode deionized water wash 3-5 time, according to mass ratio GO: AgNO ₃=1:0.79, takes 79mg AgNO ₃be dissolved in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄take 1g NaBH at=1: 10 ₄be dissolved in 50ml water, splash in mixed solution, heat 2h at 80 DEG C;

4, use deionized water and dehydrated alcohol alternately to wash to pH=7, utilize magnetic resolution to obtain black precipitate, adopt 60 DEG C of vacuum-dryings, the black powder obtaining is RGO/Fe ₃o ₄/ Ag trielement composite material.

The XRD spectra of embodiment 1 product is shown in Fig. 1.Be that 1:1 evenly mix with solid paraffin according to mass ratio by the powdered product in embodiment 1, in particular manufacturing craft, be pressed into the coaxial sample of external diameter 7.00mm, internal diameter 3.04mm, the about 3mm of thickness, be that HP8720ES vector network analyzer is tested its absorbing property by model, test frequency is 2-18GHz.As shown in Figure 4, the matching thickness of this sample is 1.6mm to its absorbing property, reaches maximum absorption to be-47.1dB in the time of 16.7GHz, inhale ripple at 14.5-18GHz to reach-below 10dB, effectively absorbing width is 3.5GHz.

Embodiment 2

1, the GO aqueous solution that compound concentration is 0.5mg/ml, the NaOH aqueous solution of preparation 1mol/L is for subsequent use;

2, according to mass ratio GO:FeCl ₂4H ₂o:FeCl ₃6H ₂o=1:2.58:3.52 takes 258mg FeCl ₂4H ₂o and 352mg FeCl ₃6H ₂o, joins in the 200ml GO aqueous solution, and heating in water bath to 50 DEG C keeps 10min, and dripping NaOH solution adjusting pH of mixed is 11, and mixed solution heats 3h at 70 DEG C;

3, be dissolved in 200ml deionized water after the black precipitate that obtains being adopted to centrifuge washing mode deionized water wash 3-5 time, according to mass ratio GO: AgNO ₃=1:1.58, takes 158mg AgNO ₃be dissolved in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄take 1g NaBH at=1: 10 ₄be dissolved in 50ml water, splash in mixed solution, heat 2h at 80 DEG C;

4, use deionized water and dehydrated alcohol alternately to wash to pH=7, utilize magnetic resolution to obtain black precipitate, adopt 60 DEG C of vacuum-dryings, the black powder obtaining is RGO/Fe ₃o ₄/ Ag trielement composite material.

The XRD spectra of embodiment 2 products is shown in Fig. 1.Be that 1:1 evenly mix with solid paraffin according to mass ratio by the powdered product in embodiment 2, in particular manufacturing craft, be pressed into the coaxial sample of external diameter 7.00mm, internal diameter 3.04mm, the about 3mm of thickness, be that HP8720ES vector network analyzer is tested its absorbing property by model, test frequency is 2-18GHz.As shown in Figure 5, the matching thickness of this sample is 2.6mm to its absorbing property, reaches maximum absorption to be-58.1dB in the time of 9.0GHz, inhale ripple at 7.8-10.6GHz to reach-below 10dB, effectively absorbing width is 2.8GHz; Thickness effectively absorbs width and reaches maximum in the time of 2.0mm, absorb at 10.7-14.7GHz to reach-below 10dB, effectively absorbing width is 4.0GHz.

TEM figure and the HRTEM of embodiment 2 products scheme as shown in Figures 2 and 3.As shown in Figure 2, Fe ₃o ₄load on equably the surface of RGO with Ag, particle diameter is all less than 30nm; The Fe that can clearly be found out by Fig. 3 ₃o ₄nano particle, Ag nano particle load on graphene nanometer sheet, have illustrated that the present invention has obtained stable RGO/Fe ₃o ₄/ Ag trielement composite material.

Embodiment 3

1, the GO aqueous solution that compound concentration is 0.5mg/ml, the NaOH aqueous solution of preparation 1mol/L is for subsequent use;

2, according to mass ratio GO:FeCl ₂4H ₂o:FeCl ₃6H ₂o=1:2.58:3.52 takes 258mg FeCl ₂4H ₂o and 352mg FeCl ₃6H ₂o, joins in the 200ml GO aqueous solution, and heating in water bath to 50 DEG C keeps 10min, and dripping NaOH solution adjusting pH of mixed is 11, and mixed solution heats 3h at 70 DEG C;

3, be dissolved in 200ml deionized water after the black precipitate that obtains being adopted to centrifuge washing mode deionized water wash 3-5 time, according to mass ratio GO: AgNO ₃=1:3.15, takes 315mg AgNO ₃be dissolved in above-mentioned mixed solution, stir 20min, according to mass ratio GO: NaBH ₄take 1g NaBH at=1: 10 ₄be dissolved in 50ml water, splash in mixed solution, heat 2h at 80 DEG C;

4, use deionized water and dehydrated alcohol alternately to wash to pH=7, utilize magnetic resolution to obtain black precipitate, adopt 60 DEG C of vacuum-dryings, the black powder obtaining is RGO/Fe ₃o ₄/ Ag trielement composite material.

The XRD spectra of embodiment 3 products is shown in Fig. 1.Be that 1:1 evenly mix with solid paraffin according to mass ratio by the powdered product in embodiment 6, in particular manufacturing craft, be pressed into the coaxial sample of external diameter 7.00mm, internal diameter 3.04mm, the about 3mm of thickness, be that HP8720ES vector network analyzer is tested its absorbing property by model, test frequency is 2-18GHz.As shown in Figure 6, the matching thickness of this sample is 4.1mm to its absorbing property, reaches maximum absorption to be-39.0dB in the time of 6.6GHz, inhale ripple at 5.7-7.2GHz to reach-below 10dB, effectively absorbing width is 1.5GHz; Thickness effectively absorbs width and reaches maximum in the time of 2.0mm, absorb at 12.4-14.6GHz to reach-below 10dB, effectively absorbing width is 2.4GHz.

Claims (1)

1. a redox graphene/Fe ₃o ₄the preparation method of the nano combined absorbing material of/Ag, is characterized in that step is as follows:

Step 1: the GO graphite oxide aqueous solution that compound concentration is 0.2-2mg/ml, the NaOH aqueous solution of preparation 0.5-5mol/L;

Step 2: according to mass ratio GO: FeCl ₂4H ₂o: FeCl ₃6H ₂o=1: x: (0.8-1.8) x, wherein x=(0.1-10), takes FeCl ₂4H ₂o and FeCl ₃6H ₂o, then joins in GO graphite oxide aqueous solution, and heating in water bath is to 30-50 DEG C of maintenance 10min, and dripping NaOH aqueous solution adjusting pH of mixed is 9-12, and above-mentioned mixed solution heats 2-3h and forms black precipitate at 60-80 DEG C;

Step 3: be dissolved in 100-400ml deionized water after the black precipitate that obtains is adopted to centrifuge washing mode deionized water wash 3-5 time, according to mass ratio GO: AgNO ₃=1:(0.1-5) mix after stir 20min obtain mixed solution; Again according to mass ratio GO: NaBH ₄=1: (5-30), take NaBH ₄be dissolved in 50-200ml water, and splash in mixed solution, at 20-100 DEG C, heat 0.5-2h;

Step 4: product that step 3 is obtained uses deionized water and dehydrated alcohol alternately to wash to pH=7, utilizes magnetic resolution, the black precipitate that centrifugal or suction filtration obtains, then to adopt the black powder that 40-80 DEG C of vacuum-drying obtains be redox graphene/Fe ₃o ₄the nano combined absorbing material of/Ag.

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