CN106268820B - Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application - Google Patents

Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application Download PDF

Info

Publication number
CN106268820B
CN106268820B CN201610649362.2A CN201610649362A CN106268820B CN 106268820 B CN106268820 B CN 106268820B CN 201610649362 A CN201610649362 A CN 201610649362A CN 106268820 B CN106268820 B CN 106268820B
Authority
CN
China
Prior art keywords
composite material
nanocrystalline
cobalt
graphene
cobalt protoxide
Prior art date
Application number
CN201610649362.2A
Other languages
Chinese (zh)
Other versions
CN106268820A (en
Inventor
杨晓晶
吴红
孙根班
Original Assignee
北京师范大学
北京师大科技园科技发展有限责任公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 北京师范大学, 北京师大科技园科技发展有限责任公司 filed Critical 北京师范大学
Priority to CN201610649362.2A priority Critical patent/CN106268820B/en
Publication of CN106268820A publication Critical patent/CN106268820A/en
Application granted granted Critical
Publication of CN106268820B publication Critical patent/CN106268820B/en

Links

Abstract

The embodiment of the invention discloses a kind of cobalt protoxide it is nanocrystalline-graphene composite material, graphene in the composite material is in the form of sheets, and cobalt protoxide is nanocrystalline is dispersed on graphene, the embodiment of the invention also discloses the preparation method of the composite material and its in the application of catalytic field.Using graphene as substrate in the present invention, by one step of thermal decomposition method restore to obtain cobalt protoxide it is nanocrystalline-graphene composite material, be free of Co in the composite material3O4Or simple substance Co, pure CoO is obtained, and CoO is nanocrystalline is uniformly dispersed, soilless sticking phenomenon makes its catalytic performance obtain very big improvement to make the composite material with good absorbing property and while magnetic property.

Description

Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application

Technical field

The present invention relates to field of material preparation, in particular to a kind of cobalt protoxide is nanocrystalline-graphene composite material, its system Preparation Method and application.

Background technique

Cobalt protoxide (CoO) is used as typical transition metal oxide, and there are two types of the object phases being typically stabilized, that is, is in The rock-salt phase (space group Fm3m) of buff and greeny wurtzit phase (space group P63mc).CoO is excellent Magnetic material, the transformation of paramagnetic and diamagnetic body nearby occurs in its Neel temperature (298K).Block-like CoO material is insulation Antiferromagnetic materials, but CoO (nano Co O) material of nanostructure shows good ferromagnetism or superparamagnetism.It receives Rice CoO material has physically better and chemical property, in lithium ion battery, electro-magnetic wave absorption, catalysis, gas transport and magnetic Data storage device etc., which all has, to be widely applied.

In many applications of nano Co O material, catalytic performance is the hot spot of research.For example, CoO nano wire can be catalyzed point Solve the harmful organic substance in air and water body, mesoporous Mn3O4- CoO presents CO catalysis oxidation and redox reactions (ORR) Preferable catalytic performance etc..

However, often containing Co in existing nano Co O material3O4Or simple substance Co, pure CoO is obtained with one Fixed difficulty.Meanwhile the nanocrystalline easy reunion of CoO, influence the catalytic performance of nano Co O material.

Summary of the invention

The embodiment of the invention discloses a kind of cobalt protoxide it is nanocrystalline-graphene composite material, preparation method and application, To solve the problems, such as that existing nano Co O material contains impurity and the nanocrystalline easy reunion of nano Co O.Technical solution is as follows:

In a first aspect, the embodiment of the invention provides a kind of cobalt protoxide it is nanocrystalline-graphene composite material, the graphite In the form of sheets, and the cobalt protoxide is nanocrystalline is dispersed on the graphene for alkene.

Wherein, it is face-centred cubic structure that the cobalt protoxide is nanocrystalline.

Wherein, the nanocrystalline partial size of the cobalt protoxide is 1-6nm, average grain diameter 3nm.

Second aspect, the embodiment of the invention also provides the preparation methods of the composite material, comprising:

Graphite oxide is added in N-Methyl pyrrolidone to and is carried out decentralized processing, obtains mixed liquor;

Acetylacetone cobalt and octadecylamine are added into the mixed liquor, are heated to the mixed liquor under stirring It 120-140 DEG C, heat preservation 30 minutes or more, then proceedes under stirring, is heated to 190-202 DEG C, heat preservation 2 hours or more;

Addition organic solvent will react sudden and stop, and isolate reaction product, and the reaction product is washed and dried Processing;

Wherein, the acetylacetone cobalt and the graphite oxide ratio are 1mol:(20-40) g, the graphite oxide and institute The mass ratio for stating octadecylamine is 1:(12.5-50), the ratio of the N-Methyl pyrrolidone and the graphite oxide is 1L:1g.

Preferably, the decentralized processing is ultrasonic disperse processing.

It is preferably, described to be heated to 190-202 DEG C, specifically: it is heated to 202 DEG C.

Preferably, the organic solvent is ethyl alcohol.

Preferably, the carrying out washing treatment are as follows: carry out alternately carrying out washing treatment with n-hexane and acetone.

The third aspect, the embodiment of the invention also provides the composite material catalytic field application.

As it can be seen that using graphene as substrate in this programme, by one step of thermal decomposition method restore to obtain cobalt protoxide it is nanocrystalline-stone Black alkene composite material is free of Co in the composite material3O4Or simple substance Co, pure CoO is obtained, and the nanocrystalline dispersion of CoO is equal Even, soilless sticking phenomenon makes its catalytic performance to make the composite material with good absorbing property and while magnetic property Very big improvement is obtained.

Detailed description of the invention

In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with It obtains other drawings based on these drawings.

The cobalt protoxide that Fig. 1 is graphite oxide (GO), prepared by graphene (GN) and the embodiment of the present invention 1 is nanocrystalline-graphite The XRD diagram of alkene composite material;

Fig. 2 be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-the XPS spectrum figure of graphene composite material;

Fig. 3 be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-electron microscope picture of graphene composite material;

Fig. 4 be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-loss of the microwave reflection rate of graphene composite material The relational graph of value and thickness of sample, frequency;

Fig. 5 be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-intensity of magnetization and temperature of graphene composite material Relational graph;

Fig. 6 be the embodiment of the present invention 1 prepare cobalt protoxide it is nanocrystalline-graphene composite material catalysis reduction CO2Electricity The relational graph of current density and current potential.

Specific embodiment

The embodiment of the invention discloses a kind of cobalt protoxide it is nanocrystalline-graphene composite material, wherein graphene (GN) is in Two-dimensional slice stratiform, cobalt protoxide (CoO) is nanocrystalline to be dispersed on the lamella of graphene.The cobalt protoxide is nanocrystalline-and graphene is multiple CoO in condensation material nanocrystalline is face-centred cubic structure, and partial size 1-6nm, average grain diameter is about 3nm.

The embodiment of the invention also discloses the cobalt protoxide it is nanocrystalline-preparation method of graphene composite material, can wrap Include following steps:

Graphite oxide is added in N-Methyl pyrrolidone to and is carried out decentralized processing, obtains mixed liquor;

Acetylacetone cobalt and octadecylamine are added into the mixed liquor, are heated to the mixed liquor under stirring It 120-140 DEG C, heat preservation 30 minutes or more, then proceedes under stirring, is heated to 190-202 DEG C, heat preservation 2 hours or more;

Addition organic solvent will react sudden and stop, and isolate reaction product, and the reaction product is washed and dried Processing;

Wherein, the acetylacetone cobalt and the graphite oxide ratio are 1mol:(20-40) g, the graphite oxide and institute The mass ratio for stating octadecylamine is 1:(12.5-50), the ratio of the N-Methyl pyrrolidone and the graphite oxide is 1L:1g.

Graphene is the two dimensional crystal for the only one layer of atomic thickness being made of carbon atom, its lattice is by six carbon originals The hexagon that son surrounds.Graphene is known, most thin, most hard nano material at present, and surface area is big, and light weight is led Electrical property is fabulous, has good flexibility and corrosion resistance, allows to carry out compound, sheet as base material and other materials Compound using graphene as base material and the nanocrystalline progress of CoO in invention, CoO is nanocrystalline can be highly dispersed to be grown in stone On the two-dimensional slice of black alkene.

Actually prepare the cobalt protoxide it is nanocrystalline-graphene composite material when, graphite oxide first can be added to N- In methyl pyrrolidone and decentralized processing is carried out, obtains mixed liquor.Specifically, the ratio of N-Methyl pyrrolidone and graphite oxide It can be 1L:1g.The decentralized processing can be preferably ultrasonic using dispersing modes such as ultrasonic disperse, mechanical stirring decentralized processings Decentralized processing.When suspended matter is not present in the mixed liquor, when obtaining the uniform brown mixed solution of color, the mixed liquor is illustrated It is dispersed uniformly, decentralized processing can be stopped.It should be noted that the decentralized processing is processing mode commonly used in the art, It does not illustrate herein.

Explanation is needed further exist for, graphite oxide can be bought from market, can also pass through existing preparation method system , those skilled in the art can select according to actual needs, be not specifically limited herein.Oxygen used in the present invention Graphite is made by following improved Hummers methods, and the graphite oxide degree of oxidation using this method preparation is high, dispersion effect Fruit is good, more conducively cobalt protoxide it is nanocrystalline-preparation of graphene composite material.

It is specific the preparation method is as follows:

2.5g graphite powder, 2.5g sodium nitrate and the 115mL concentrated sulfuric acid are weighed, is placed in ice-water bath, under stirring slowly 15g KMnO is added4;After about 15 minutes, ice-water bath is removed, is put into 35 DEG C of water-baths, is slowly added to 230mL distilled water, product Brown is become from black;It is then placed in 98 DEG C of oil baths, after heat preservation 15 minutes, removes oil bath, 700mL warm water is added, stir shape 50mL hydrogen peroxide is added under state, product becomes golden yellow;After being filtered processing to product, with mass percent be 5% it is dilute HCl solution washing, then is washed with distilled water 5-10 times, until in filtrate without SO4 2-Until;By products therefrom in 70 DEG C of drying boxes In be dried, obtain graphite oxide.

After obtaining above-mentioned finely dispersed mixed liquor, acetylacetone cobalt and octadecylamine are added into the mixed liquor, The mixed liquor is heated to 120-140 DEG C under stirring, heat preservation 30 minutes or more, then proceedes under stirring, heats To 190-202 DEG C, heat preservation 2 hours or more.Specifically, acetylacetone cobalt and graphite oxide ratio can be 1mol:(20-40) g, Preferably 1mol:20g.The mass ratio of graphite oxide and octadecylamine can be 1:(12.5-50), preferably 1:12.5.

Wherein, octadecylamine, on the one hand for preventing CoO nanometers of crystals growths uneven, advantageously forms list as confinement agent The CoO of dispersion is nanocrystalline, and on the other hand, octadecylamine, can be to avoid Co as a kind of reducing agent3+Generation, while reduction-oxidation Graphite is graphene, conducive to the generation of composite material.When inventor has found that the mass ratio of graphite oxide and octadecylamine is 1:12.5 More cost-effectively, be conducive to the generation of composite material.

The mixed liquor is heated to 120-140 DEG C, heat preservation 30 minutes or more, the nanocrystalline nucleation of CoO can be made and grown, it can With understanding, soaking time is longer, and the effect of the nanocrystalline nucleation of CoO and growth is better, but soaking time is too long not only Preparation efficiency is reduced, also will increase the cost for preparing composite material.The mixed liquor is heated to 120 DEG C by inventor's discovery, is protected At temperature 30 minutes, preparation efficiency is high and cost is relatively low, therefore the mixed liquor is preferably heated to 120 DEG C, keeps the temperature 30 minutes.

Further, heating and isothermal holding are carried out under stirring can make acetylacetone cobalt, graphite oxide and ten Eight amine mix more uniform in N-Methyl pyrrolidone, and then make to react more uniform, are conducive to the generation of composite material. Preferably, which can be magnetic agitation state.It can certainly be other agitating modes, as long as not influencing composite wood The generation of material and can reach stirring purpose, be not specifically limited herein.

It similarly,, can be in order to further provide favorable environment for the nanocrystalline growth of CoO after above-mentioned isothermal holding Continue under stirring, is heated to 190-202 DEG C, heat preservation 2 hours or more.It is excellent in view of the requirement of preparation efficiency and cost It is selected as being heated to 202 DEG C (boiling point of N-Methyl pyrrolidone is 202 DEG C), keeps the temperature 2 hours.The stirring may be magnetic force Stirring, naturally it is also possible to be other agitating modes, as long as not influencing the generation of composite material and stirring purpose can be reached , it is not specifically limited herein.

In order to which the CoO for being prepared of uniform size is nanocrystalline, it can will react sudden after above-mentioned second of isothermal holding and stop. Specifically mixed liquor can be made to cool down rapidly after organic solvent is added by the way of organic solvent is added, and then will reaction Sudden to stop, which is preferably ethyl alcohol.

After reacting sudden and stopping, need to carry out separating treatment, i.e., by prepared cobalt protoxide it is nanocrystalline-graphene composite wood Material is separated with mixed liquor, can be carried out separating treatment using the modes such as centrifugation or filtering, is preferably centrifugated.Separation is produced After object, alternately carrying out washing treatment can be carried out to product n-hexane and acetone, is then dried, is obtained cobalt protoxide and receive Meter Jing-graphene composite material.For washing times, can be selected by those skilled in the art according to actual product situation It selects, such as can be 3 times or 4 times, be not specifically limited herein.Drying process can be done product in 40 DEG C of progress vacuum Dry processing, naturally it is also possible to use other drying process modes, be not specifically limited herein.

The present invention also provides cobalt protoxide prepared by the above method it is nanocrystalline-graphene composite material for be catalyzed neck The purposes in domain.

It should be noted that above-mentioned dispersion, stirring, to be centrifuged, be filtered, washed and be dried be place commonly used in the art Reason method, those skilled in the art can operate according to practical preparation situation, be not specifically limited and illustrate herein.

Explanation is needed further exist for, the used raw material in preparing the composite material can be on the market It buys or makes by oneself, be not specifically limited herein.

It is described below in conjunction with technical solution in the embodiment of the present invention of the embodiment of the present invention, it is clear that described Embodiment be only a part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ability Domain those of ordinary skill every other embodiment obtained without creative efforts, belongs to guarantor of the present invention The range of shield.

Embodiment 1

40mg graphite oxide (GO) is added in 40mL N-Methyl pyrrolidone, after carrying out ultrasonic disperse about 2 hours, Obtain finely dispersed brown mixture;

By 2mmol acetylacetone cobalt (Co (acac)2) and 0.5g octadecylamine be added into above-mentioned brown mixture, in magnetic force It is heated to 120 DEG C under stirring, keeps the temperature 30 minutes, then proceedes to be heated to 202 DEG C under magnetic agitation state, heat preservation 2 is small When;

20mL ethyl alcohol, which is added, will react sudden and stops, and then carry out centrifugal treating, isolate reaction product, and with n-hexane, third Alternately after washing 3 times, product is dried in vacuo in 40 DEG C for ketone.

Embodiment 2

40mg graphite oxide (GO) is added in 40mL N-Methyl pyrrolidone, after carrying out ultrasonic disperse about 2 hours, Obtain finely dispersed brown mixture;

By 1mmol acetylacetone cobalt (Co (acac)2) and 1.4g octadecylamine be added into above-mentioned brown mixture, in magnetic force It is heated to 125 DEG C under stirring, keeps the temperature 40 minutes, then proceedes to be heated to 190 DEG C under magnetic agitation state, heat preservation 3 is small When;

20mL ethyl alcohol, which is added, will react sudden and stops, and then carry out centrifugal treating, isolate reaction product, and with n-hexane, third Alternately after washing 4 times, product is dried in vacuo in 40 DEG C for ketone.

Embodiment 3

30mg graphite oxide (GO) is added in 30mL N-Methyl pyrrolidone, after carrying out ultrasonic disperse about 2 hours, Obtain finely dispersed brown mixture;

By 1mmol acetylacetone cobalt (Co (acac)2) and 1.5g octadecylamine be added into above-mentioned brown mixture, in magnetic force It is heated to 140 DEG C under stirring, keeps the temperature 60 minutes, then proceedes to be heated to 195 DEG C under magnetic agitation state, heat preservation 4 is small When;

20mL ethyl alcohol, which is added, will react sudden and stops, and then carry out centrifugal treating, isolate reaction product, and with n-hexane, third Alternately after washing 5 times, product is dried in vacuo in 40 DEG C for ketone.

Characterization and analysis

1, X-ray diffraction (X-ray Diffraction, XRD) is analyzed

The x-ray powder diffraction instrument (model: X Pert PRO MPD) produced using Dutch PAN alytical company is right Cobalt protoxide prepared by graphene (GN) used in graphite oxide (GO) prepared by the present invention, the present invention and the embodiment of the present invention 1 It is as shown in Figure 1 that nanocrystalline-graphene composite material carries out the XRD diagram that characterization measures.

(a) is that the XRD diagram of the invention for preparing graphite oxide is obtained by aoxidizing to graphite as seen from the figure in Fig. 1 The interlamellar spacing of GO be(original graphite is about), while having a typical diffraction in 2 θ=10.8 ° positions Peak, and the typical diffractive peak (2 θ=26.5 °) of original graphite disappears, and illustrates that the GO obtained is effectively aoxidized.

(b) is that the XRD diagram of graphene used in the present invention occurs within the scope of 2 θ=20-30 ° as seen from the figure in Fig. 1 One apparent diffraction corona, while having a weak diffraction maximum in 2 θ=43.2 °, (002) and (100) face of GN is respectively corresponded, Show that amorphous carbon exists, and GO is reduced to GN.

In Fig. 1 (c) be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-XRD diagram of graphene composite material, by Figure as it can be seen that the cobalt protoxide of preparation of the embodiment of the present invention it is nanocrystalline-diffraction peak of graphene composite material in 2 θ=36.5 °, 42.4 °, 61.6 °, 73.5 ° and 77.0 °, by being compared with standard card that PDF card number is 48-1719, it was demonstrated that acquisition is CoO.Further indexing is it is found that the diffraction maximum of sample corresponds respectively to (111), (200), (220), (311) and (222) crystalline substance Face, interlamellar spacing are respectively 0.246,0.213,0.150,0.128 and 0.123nm, corresponding face-centred cubic structure, and space group is Fm3m.Meanwhile the cobalt protoxide of preparation of the embodiment of the present invention it is nanocrystalline-graphene composite material in, the diffraction maximum of GO disappears, It proves that GO is not present, it is related that this may be reduced into unbodied GN with GO.The cobalt protoxide of preparation of the embodiment of the present invention is received Meter Jing-graphene composite material XRD diffraction maximum is significantly broadened, thus it is speculated that the nanocrystalline size of obtained CoO is smaller.

2, x-ray photoelectron spectroscopy (X-ray Photoelectron Spectroscopy, XPS) is analyzed

The cobalt protoxide prepared using XPS spectrum instrument (model: ESCALAB 250Xi) to the embodiment of the present invention 1 is nanocrystalline- It is as shown in Figure 2 that the surface composition of graphene composite material and the valence state of cobalt carry out the XPS spectrum figure that characterization measures.

In Fig. 2 (a) be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-XPS of the C1s of graphene composite material Map.For carbon material, general 288.9,287.7,286.0 and 284.7eV respectively correspond O=C-O, C=O, O-C-O and C- The combination energy of C.In Fig. 2 (a) as it can be seen that cobalt protoxide it is nanocrystalline-graphene composite material in, the corresponding peak 288.9eV disappears It losing, the corresponding peak in 287.7 and 286.0eV or so weakens, i.e. and the cobalt protoxide of preparation of the embodiment of the present invention is nanocrystalline-and graphene is multiple O=C-O functional group is practically free of in condensation material, and the content of O=C and O-C-O is seldom, mainly with the presence of C-C structure.Show this Inventive embodiments preparation cobalt protoxide it is nanocrystalline-graphene composite material in, oxygen-containing functional group is effectively reduced.

In Fig. 2 (b) be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-the Co 2p of graphene composite material XPS spectrum figure.Corresponding peak belongs to the 2p of cobalt near 780.72eV in figure3/2Peak, it is corresponding near simultaneous 786.10eV to defend Star peak (satellite peak).Corresponding peak belongs to the 2p of cobalt near 796.75eV1/2Peak, simultaneous 802.69eV are attached Close corresponding satellites.It can difference Δ E, that is, cobalt 2p it can be seen from the figure that combining3/2The corresponding combination energy 796.75eV in peak, With the 2p of cobalt1/2The difference of the corresponding combination energy 780.72eV in peak is 16.03eV.Due to being shown to be divalent when Δ E is 16eV Cobalt (CoO);When Δ E is 15eV, it is shown to be the cobalt (Co of trivalent2O3);When Δ E is 15.2eV, it is shown to be divalent and trivalent Cobalt mixed valence, such as Co3O4, so the embodiment of the present invention preparation cobalt protoxide it is nanocrystalline-graphene composite material in What is obtained is divalent cobalt, i.e. CoO, does not contain trivalent cobalt.Meanwhile showing the present invention without corresponding peak near 778.10eV Embodiment preparation cobalt protoxide it is nanocrystalline-graphene composite material in do not contain metal Co simple substance.XPS spectrum data and XRD Data are consistent, show cobalt protoxide it is nanocrystalline-graphene composite material can through the invention provided by method be made.

3, electron microscopy image analysis

(a) is scanning electron microscope (the Scanning Electron using Hitachi company in Fig. 3 Microscope, SEM, model: S-4800, acceleration voltage: 5kV) nanocrystalline to the cobalt protoxide of the preparation of the embodiment of the present invention 1- Graphene composite material carries out the SEM figure that characterization measures.As seen from the figure, large stretch of graphene-supported tiny CoO is nanocrystalline, CoO is nanocrystalline to be uniformly dispersed on graphene sheet layer, illustrates that the preparation method provided through the invention can be prepared on a large scale Out cobalt protoxide it is nanocrystalline-graphene composite material.

In Fig. 3 (b)-(d) be the cobalt protoxide that prepared by the embodiment of the present invention 1 using transmission electron microscope it is nanocrystalline- Graphene composite material carry out characterization measure transmission electron microscope (Transmission Electron Microscope, TEM) figure.From Fig. 3 (b) and (c) as can be seen that the embodiment of the present invention preparation cobalt protoxide it is nanocrystalline-graphene composite wood CoO in material nanocrystalline is spheric granules, is distributed on the lamella of graphene to CoO nanocrystalline high-density, monodisperse.In Fig. 3 (c) figure of upper right corner insertion is the nanocrystalline partial size ruler of the CoO that is counted according to the nanocrystalline partial size of the CoO in multiple TEM figures Very little distribution map, it can be seen in the figure that CoO nanocrystalline partial size is about 1-6nm, preferably 1.5-4.5nm, average grain diameter is about 3nm.(d) is it will be clear that the edge of graphene illustrates to invent almost without the superposition phenomenon of graphene sheet layer from 3 Embodiment preparation cobalt protoxide it is nanocrystalline-graphene composite material in graphene it is very thin, and do not have agglomeration.Meanwhile CoO is nanocrystalline to be firmly grown on graphene sheet layer.

In Fig. 3 (e) and (f) for using high resolution electron microscope (High Resolution Transmission Electron Microscopy, HRTEM, model: JEM-2010, acceleration voltage: 200kV) prepared by the embodiment of the present invention 1 Cobalt protoxide is nanocrystalline-and graphene composite material carries out the HRTEM figure that characterization measures.(e) can significantly more see from Fig. 3 The edge of graphene again demonstrates the cobalt protoxide nanometer of inventive embodiments preparation almost without the superposition of graphene sheet layer Graphene in crystalline substance-graphene composite material is very thin, and does not have agglomeration, and nanoparticle is firmly grown in graphene sheet layer On.(f) is it can be seen that the nanocrystalline clearly lattice of CoO, spacing of lattice 0.213nm, (200) crystal face with CoO from Fig. 3 It is corresponding, illustrate that the CoO of cubic phase is nanocrystalline and is grown along (200) crystal face.

In Fig. 3 (g) be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-Selected area electron of graphene composite material Diffraction (Selected Area Electron Diffraction, SAED) figure, (g) is as can be seen that the present invention is implemented from Fig. 3 The cobalt protoxide of example preparation is nanocrystalline-and graphene composite material has clearly three rings, and it is learnt, is respectively corresponded by calculating CoO nanocrystalline (111), (200), (220) and (311) crystal face, it is consistent with XRD and XPS data.(wherein (222) crystal face is very It is weak, do not show.)

4, absorbing property result

For assessment preparation of the embodiment of the present invention cobalt protoxide it is nanocrystalline-microwave absorbing property of graphene composite material, Cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-graphene composite material with paraffin uniformly mixes the (embodiment of the present invention 1 preparation cobalt protoxide it is nanocrystalline-mass percent of graphene composite material in the mixture be 60%, paraffin does not have electromagnetism Wave absorbent properties), it is assembled into an electro-magnetic wave absorption device, the outer diameter and inner diameter of the device is 7.00nm and 3.04nm respectively, It is characterized using Agilent E8362B vector network analyzer.Test carries out under fixed frequency and thickness of sample, instead It penetrates loss value (RL) to be calculated according to microwave transmission theory, formula is as follows:

RL (dB)=20log | (Zin-Z0)/(Zin+Z0)|

Wherein, ZinFor input impedance, Z0For air impedance, μrFor relative permeability, εrFor relative dielectric constant, f is microwave Frequency, d are thickness of sample, and c is the light velocity.

Fig. 4 be cobalt protoxide prepared by the embodiment of the present invention 1 measured by above-mentioned electro-magnetic wave absorption device it is nanocrystalline-stone The microwave reflection rate loss value of black alkene composite material and the relational graph of thickness of sample.It is tested in 1.0-18.0GHz frequency range The reflection loss value of different thickness of sample with frequency variation relation.When the reflection loss value of absorbing material is -10dB, table Show that 90% electromagnetic wave is absorbed, only 10% electromagnetic wave is reflected, which is considered to have practical application value. As seen from Figure 4, with the increase of thickness of sample, the absorption frequency for minimal losses value occur is mobile to low frequency, while absorption intensity Increase, absorption band increases.By adjusting the thickness of sample, sample is in low frequency (1-6GHz), intermediate frequency (7-12GHz) and high frequency (13- Reflection loss value 18GHz) can be lower than -10dB.

Specifically, it can be seen from figure 4 that most strong absorb appears in 15.0GHz, and reflection is damaged when thickness of sample is 2mm Consumption value is -8.9dB;When thickness of sample is 3mm, most strong absorb appears in 9.5GHz, and reflection loss value is -11.0dB;Work as sample When product are with a thickness of 4mm, most strong absorb appears in 6.9GHz, and reflection loss value is -11.8dB;When thickness of sample is greater than 4mm, out When existing two most strong absworption peaks such as thickness of sample are 5mm, it is most absorbed as 5.2GHz by force, reflection loss value is -13.1dB, and 17.6GHz, reflection loss value are -22.7dB;When thickness of sample is 6mm, it being most absorbed as 4.1GHz by force, reflection loss value is- 16.3dB and 14.6GHz, reflection loss value are -20.6dB;When thickness of sample is 7mm, it is most absorbed as 2.8GHz by force, reflects Loss value is -24.0dB and 10.6GHz, and reflection loss value is -19.5dB.Minimal reflection loss value is to be in thickness of sample When 9mm, frequency reaches -31.1dB when being 2.3GHz.Meanwhile when thickness of sample is 9mm, there are three effective absorption peak (RL < -10dB), respectively appear in low frequency 2.3GHz, reflection loss value is -31.1dB, intermediate frequency 9.2GHz, reflection loss value is - 15.7dB and high frequency 16.3GHz, reflection loss value are -13.6dB, i.e., have been attained by when thickness of sample is 9mm in all band Effect absorbs.

It is well known that such absorbing material just has actual when the reflection loss value of absorbing material is lower than -10dB Application value, thus the embodiment of the present invention preparation cobalt protoxide it is nanocrystalline-graphene composite material have excellent wave absorbtion Can, practical application value can be reached.In addition, with the increase of absorbent thickness, absorption intensity increases, and absorption band to Low frequency is mobile.By adjusting the thickness of sample, reflection loss can cover 1-18GHz frequency band, it was demonstrated that preparation of the embodiment of the present invention Cobalt protoxide it is nanocrystalline-graphene composite material can by adjust thickness come reach all band absorption practical application valence Value.

5, magnetic property result

Existed using the magnetization curve test equipment (model: MPMS-s-SQUID) that Quantum Design company, the U.S. produces Magnetic field strength carries out table for nanocrystalline to the cobalt protoxide of the preparation of the embodiment of the present invention 1 under the conditions of 100Oe-graphene composite material The relational graph for levying the intensity of magnetization and temperature that measure is as shown in Figure 5.Wherein, M indicates the intensity of magnetization, and T indicates kelvin degree.

In Fig. 5 (a) be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-null field of graphene composite material is cold (ZFC) magnetization curve, in Fig. 5 (b) be cobalt protoxide prepared by the embodiment of the present invention 1 it is nanocrystalline-field of graphene composite material Cold (FC) magnetization curve.As seen from Figure 5, the cobalt protoxide of preparation of the embodiment of the present invention it is nanocrystalline-graphene composite material is zero In the cooling measurement process in field, intensity of magnetization when temperature is greater than 0K is almost nil.And in having the cooling measurement process in field, temperature is big Intensity of magnetization when 0K is not zero, and shows magnetism.And the cobalt protoxide of preparation of the embodiment of the present invention is received as can be seen from Figure 5 Meter Jing-graphene composite material does not have hysteresis, therefore, the embodiment of the present invention preparation cobalt protoxide it is nanocrystalline-graphene Composite material exhibits have gone out superparamagnetism.

6, catalytic performance result

Using linear sweep voltammetry test equipment (model: Zahner IM6) in CO2With in Ar atmosphere to of the invention real The cobalt protoxide for applying the preparation of example 1 is nanocrystalline-and graphene composite material carries out the catalysis CO that measures of characterization2Current density and current potential Relational graph it is as shown in Figure 6.

As seen from the figure, in CO2Corresponding current density absolute value is significantly greater than the corresponding electric current in Ar atmosphere in atmosphere Density absolute value, this is because also in electroreduction CO while electrolysis water2, so current density absolute value can be than only existing The current density absolute value of electrolysis water is bigger in Ar atmosphere.Generally, CO is restored2Rate determining step suddenly required for current potential be highest , it is -1.2V, this is also to restore CO in the prior art2A maximum bottleneck.It can be seen from the figure that with of the invention real Apply example preparation cobalt protoxide it is nanocrystalline-graphene composite material as catalyst, by CO2Reduction potential be reduced to- 0.7V.Moreover, current density absolute value continues to increase as current potential continues to increase, show the oxidation of preparation of the embodiment of the present invention Sub- cobalt nanocrystal-graphene composite material is as catalyst, to CO2Electro-catalysis reduction has extraordinary catalytic performance.

As it can be seen that using graphene as substrate in this programme, by one step of thermal decomposition method restore to obtain cobalt protoxide it is nanocrystalline-stone Black alkene composite material is free of Co in the composite material3O4Or simple substance Co, pure CoO is obtained, and the nanocrystalline dispersion of CoO is equal Even, soilless sticking phenomenon makes its catalytic performance to make the composite material with good absorbing property and while magnetic property Very big improvement is obtained.

Above-graphene composite material nanocrystalline to cobalt protoxide provided by the present invention, preparation method and application into It has gone and has been discussed in detail.Principle and implementation of the present invention are described for specific embodiment used herein, the above reality The explanation for applying example is merely used to help understand method and its central idea of the invention.It should be pointed out that for the common of this field , without departing from the principle of the present invention, can be with several improvements and modifications are made to the present invention for technical staff, these Improvement and modification also fall into the protection scope of the claims in the present invention.

Claims (7)

1. a kind of cobalt protoxide is nanocrystalline-graphene composite material, which is characterized in that the graphene in the form of sheets, and the oxygen Change sub- cobalt nanocrystal to be dispersed on the graphene;The nanocrystalline partial size of the cobalt protoxide is 1-6nm, average grain diameter 3nm; The composite material is prepared by the following method:
Graphite oxide is added in N-Methyl pyrrolidone to and is carried out decentralized processing, obtains mixed liquor;
Acetylacetone cobalt and octadecylamine are added into the mixed liquor, acetylacetone cobalt and 18 will be added under stirring The mixed liquor of amine is heated to 120-140 DEG C, heat preservation 30 minutes or more, then proceedes to be heated to 190-202 under stirring DEG C, heat preservation 2 hours or more;
Addition organic solvent will react sudden and stop, and isolate reaction product, and the reaction product is washed and is dried;
Wherein, the acetylacetone cobalt and the graphite oxide ratio are 1mol:(20-40) g, the graphite oxide and described ten The mass ratio of eight amine is 1:(12.5-50), the ratio of the N-Methyl pyrrolidone and the graphite oxide is 1L:1g.
2. composite material as described in claim 1, which is characterized in that the nanocrystalline cobalt protoxide is face-centred cubic structure.
3. composite material as described in claim 1, which is characterized in that the decentralized processing is ultrasonic disperse processing.
4. composite material as described in claim 1, which is characterized in that it is described to be heated to 190-202 DEG C, specifically: it is heated to 202℃。
5. composite material as described in claim 1, which is characterized in that the organic solvent is ethyl alcohol.
6. composite material as described in claim 1, which is characterized in that the carrying out washing treatment are as follows: carried out with n-hexane and acetone Alternately carrying out washing treatment.
7. described in any item composite materials of such as claim 1-6 are in the application of catalytic field.
CN201610649362.2A 2016-08-10 2016-08-10 Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application CN106268820B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201610649362.2A CN106268820B (en) 2016-08-10 2016-08-10 Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201610649362.2A CN106268820B (en) 2016-08-10 2016-08-10 Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application

Publications (2)

Publication Number Publication Date
CN106268820A CN106268820A (en) 2017-01-04
CN106268820B true CN106268820B (en) 2019-05-14

Family

ID=57667495

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201610649362.2A CN106268820B (en) 2016-08-10 2016-08-10 Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and application

Country Status (1)

Country Link
CN (1) CN106268820B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106602011B (en) * 2016-12-12 2019-06-07 北京师范大学 Cobalt protoxide is nanocrystalline-graphene composite material, preparation method and the usage

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101800302A (en) * 2010-04-15 2010-08-11 上海交通大学 Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof
CN104117683A (en) * 2014-07-01 2014-10-29 北京师范大学 Hexagonal phase nickel-cobalt alloy nanocluster-graphene composite material and preparation method and application thereof
CN104393283A (en) * 2014-10-20 2015-03-04 中国工程物理研究院化工材料研究所 Nano crystalline CoO-graphene composite material as well as preparation and application thereof
CN105817648A (en) * 2016-04-29 2016-08-03 北京师范大学 Iron-nickel alloy nanocluster-graphene composite material and preparation method and application thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101800302A (en) * 2010-04-15 2010-08-11 上海交通大学 Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof
CN104117683A (en) * 2014-07-01 2014-10-29 北京师范大学 Hexagonal phase nickel-cobalt alloy nanocluster-graphene composite material and preparation method and application thereof
CN104393283A (en) * 2014-10-20 2015-03-04 中国工程物理研究院化工材料研究所 Nano crystalline CoO-graphene composite material as well as preparation and application thereof
CN105817648A (en) * 2016-04-29 2016-08-03 北京师范大学 Iron-nickel alloy nanocluster-graphene composite material and preparation method and application thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Synthesis、characterization and electromagnetic performance of nanocomposites of graphene with α-LiFeO2 and β-LiFe5O8;Hong Wu et al.;《Journal of Materials Chemistry C》;20150427;第3卷;第5457-5466页

Also Published As

Publication number Publication date
CN106268820A (en) 2017-01-04

Similar Documents

Publication Publication Date Title
He et al. Enhanced wave absorption of nanocomposites based on the synthesized complex symmetrical CuS nanostructure and poly (vinylidene fluoride)
Zhao et al. Synthesis of flower-like CuS hollow microspheres based on nanoflakes self-assembly and their microwave absorption properties
Han et al. Graphene-wrapped ZnO hollow spheres with enhanced electromagnetic wave absorption properties
Ghosh et al. Synthesis and magnetic properties of CoO nanoparticles
Liu et al. Fabrication and photocatalysis of CuO/ZnO nano-composites via a new method
Feng et al. Reduced graphene oxide decorated with in-situ growing ZnO nanocrystals: facile synthesis and enhanced microwave absorption properties
Jiang et al. Moderate temperature synthesis of nanocrystalline Co3O4 via gel hydrothermal oxidation
Yan et al. Nanoparticles and 3D sponge-like porous networks of manganese oxides and their microwave absorption properties
Wang et al. Preparation of NiO nanoparticles and their catalytic activity in the thermal decomposition of ammonium perchlorate
Liang et al. SiC–Fe 3 O 4 dielectric–magnetic hybrid nanowires: controllable fabrication, characterization and electromagnetic wave absorption
Yang et al. Spherical hollow assembly composed of Cu2O nanoparticles
Zheng et al. Hydrophobic graphene nanosheets decorated by monodispersed superparamagnetic Fe 3 O 4 nanocrystals as synergistic electromagnetic wave absorbers
Ma et al. A facile fabrication and highly tunable microwave absorption of 3D flower-like Co3O4-rGO hybrid-architectures
Wu et al. Facile synthesis of urchin-like ZnO hollow spheres with enhanced electromagnetic wave absorption properties
Rehman et al. Size effects on the magnetic and optical properties of CuO nanoparticles
Zhang et al. Polymer-composite with high dielectric constant and enhanced absorption properties based on graphene–CuS nanocomposites and polyvinylidene fluoride
Chen et al. Microwave absorption properties of SrFe12O19/ZnFe2O4 composite powders
Zhao et al. Facile synthesis of yolk–shell Ni@ void@ SnO 2 (Ni 3 Sn 2) ternary composites via galvanic replacement/Kirkendall effect and their enhanced microwave absorption properties
Wu et al. Synthesis and characterization of γ-Fe2O3@ C nanorod-carbon sphere composite and its application as microwave absorbing material
Lima et al. Ni–Zn nanoferrite for radar-absorbing material
Omri et al. Magnetic and optical properties of manganese doped ZnO nanoparticles synthesized by sol–gel technique
Chen et al. Size-controlled synthesis and magnetic properties of NiFe2O4 hollow nanospheres via a gel-assistant hydrothermal route
Wang et al. A facile one-pot method to synthesize a three-dimensional graphene@ carbon nanotube composite as a high-efficiency microwave absorber
Wei et al. Preparation of hierarchical core-shell C@ NiCo2O4@ Fe3O4 composites for enhanced microwave absorption performance
Ni et al. Designed synthesis of wide range microwave absorption Fe3O4–carbon sphere composite

Legal Events

Date Code Title Description
C06 Publication
C10 Entry into substantive examination
GR01 Patent grant