• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    溶液穩(wěn)定、高導(dǎo)電性波紋狀石墨烯片

    2012-12-11 09:12:22范承偉王海芳曹傲能
    物理化學(xué)學(xué)報 2012年10期
    關(guān)鍵詞:上海大學(xué)導(dǎo)電性波紋

    范承偉 張 新 陳 勝 王海芳 曹傲能

    (上海大學(xué)納米化學(xué)與生物學(xué)研究所,上海200444)

    溶液穩(wěn)定、高導(dǎo)電性波紋狀石墨烯片

    范承偉 張 新 陳 勝 王海芳 曹傲能*

    (上海大學(xué)納米化學(xué)與生物學(xué)研究所,上海200444)

    特殊的單原子層二維sp2碳結(jié)構(gòu)給石墨烯帶來眾多獨特的性能和潛在的應(yīng)用.然而,單層石墨烯容易聚集并會逐漸重新石墨化,這成為其應(yīng)用的一個重要障礙.本文報道了一種新策略來解決這個問題,即通過在石墨烯表面引入sp2碳納米結(jié)構(gòu)作為永久的波紋來阻止石墨烯的聚集和石墨化,并使之在溶液中易于分散和穩(wěn)定.和其他功能化方法不同,該方法沒有引入雜原子,不破壞石墨烯的結(jié)構(gòu)和功能.制得的石墨烯具有優(yōu)異的導(dǎo)電性能(~65000 S·m-1),并具有較好的溶液穩(wěn)定性.

    石墨烯;波紋;碳納米籠;可膨脹石墨;導(dǎo)電性;溶液穩(wěn)定性

    1 Introduction

    Graphene was once regarded unable to exist.1Recent experiments and simulation suggest that it is the transient ripples in three dimension that make the two dimensional(2D)graphene stable.2-4The peculiar 2D structure offers graphene many unique properties and potential applications.5-9Many applications of graphene require solution-processable graphene sheets of high quality in quantity.6,10-20However,one serious obstacle is that graphene is prone to aggregate in suspension and gradually stacks back to graphite.

    Currently,most of the solution-processable graphene is the chemically converted graphene or reduced graphene oxide (rGO).13,14,20-25Graphene oxide(GO)is soluble and can be produced cheaply and massively.GO also has many potential applications,26-28but it is electrically insulating and not suitable for many applications.Various methods have been developed to reduce GO and turn it into conductive rGO,10,15but rGO still has substantial content of oxygen,and no longer stable in solution.In some applications,an effective way to avoid the re-stacking of rGO is to synthesize the final graphene-composite material directly from soluble graphene oxide(GO),skipping the graphene-producing step,as we demonstrated previously.15But for many applications,the graphene-producing step is necessary.Chemical exfoliation of graphite or expanded graphite is a promising method to produce solution-processable high-quality graphene,11,12,29-31yet the suspension is not very stable,and the concentration of graphene is usually very low.To stabilize it in suspension,graphene is usually functionalized by either non-covalent or covalent methods.6,16,17,22These methods introduce heteroatoms and molecules onto graphene that usually deteriorate the structure and properties of graphene.Here we report a facile method to produce high-quality solution-processable graphene sheets.The basic idea is to introduce sp2carbon nano-islands on graphene sheet as permanent ripples to prevent the stacking and graphitization of graphene and to make graphene easy to re-suspend.Unlike most functionalization methods,the sp2carbon decoration does not deteriorate the structure and properties of graphene.Therefore,the obtained permanently rippled graphene sheets show significantly increased solubility as well as excellent electronic conductivity.

    2 Experimental

    2.1 Synthesis

    The procedure to prepare the permanently rippled graphene (denoted as GC)is simple,as depicted in Scheme 1.In a typical experiment,0.2 g expandable graphite(EG,chemical grade,~300 μm,from Qingdao BCSM Co.,Ltd.,China)was mixed with 2 mg ferrocene(98%,chemical grade,Sinopharm Chemical Reagent Co.,Ltd.,China),and heated in a microwave oven (800 W,Galanz,G80D23CN2P-T7(B0),China)for 15 s.After microwaving,the volume of the sample expands to more than 200 times of the original.The entirely expanded graphite was then treated with 1.2 mol·L-1hydrochloric acid(Sinopharm Chemical Reagent Co.,Ltd.,China)at 60°C overnight to remove deposited iron particles,followed by washing with deionized water and ethanol.The sample was then dried at 80°C for 12 h.Five milligram of the above sample was sonicated mildly in 50 mLN-methylpyrrolidone(NMP,analytical grade,Sinopharm Chemical Reagent Co.,Ltd.,China)for 75 min under ambient condition.After centrifugation at 3000 r·min-1for 5 min to remove the unexfoliated graphite,the resulted black GCsuspension was stable for several days.EG was also treated following the above procedure without adding ferrocene,and the obtained graphene was denoted as GP.Nature graphite(chemical grade,Sinopharm Chemical Reagent Co.,Ltd.,China)was exfoliated in NMP at the same conditions,too.rGO was prepared for comparison by hydrazine-reduction as reported previously.15

    Since the microwave reaction completed too quickly to capture the intermediates of the reaction,we also used a conventional chemical vapor deposition(CVD)method to slow down the process.To achieve good mixing,EG was first expanded alone(without ferrocene)by microwaving,then exfoliated in NMP.The suspension was centrifuged at 3000 r·min-1for 5 min,and the supernatant was filtered and dried.Two mg of the dried powder and 200 mg of ferrocene(because of the inefficiency of CVD method,extra ferrocene has to be used)were put in a quartz boat,and heated with CVD method at 600-950°C for a certain period of time.After cooling down to room temperature,the products were suspended in ethanol and examed by transmission electron microscope(TEM).

    2.2 Characterization

    Scheme 1 Synthesis process of the permanently rippled graphene

    High-resolution TEM images and energy dispersive spectrometer(EDS)spectra were taken on a JEM-2010F microscope(JEOL,Japan).Samples were prepared by drop-casting onto holey carbon grids(300 mesh size)and dried at 80°C for 4 h.Field emission scanning electron microscope(FESEM) images were recorded on a JSM-6700F electron microscope (JEOL,Japan).Raman spectra were collected on a Renishaw invia plus laser Raman spectrometer(UK)with an excitation laser wavelength of 514.5 nm(5 mW)at room temperature. Samples for both FESEM and Raman were prepared by spraying the graphene suspensions on SiO2/Si substrate(SiO2thickness of 300 nm)and annealing under nitrogen gas at 400°C for 4 h.Fourier transform infrared(FTIR)spectra were recorded on a Thermo Nicolet Avatar 370 FTIR spectrometer(USA) with a resolution of 2 cm-1.X-ray photoelectron spectroscopy (XPS)data were collected on an AXIS ultra instrument(Kratos,UK)at 293 K,and a binding energy of 284.6 eV for the C 1s level was used as an internal reference.XPS peaks were deconvoluted using XPS peak 4.1.TGA measurement was performed on a TGA-SDT Q600(TA Instruments,USA)under a nitrogen flow(100 mL·min-1),at a rate of 5°C min-1.Electronic conductivity measurements were carried out on a SB100/A Test Unit(Qianfeng Electronic Instrument,China)using a four-point-probe head with a pin-distance of about 3 mm,samples were prepared by compressing graphene powder at 20 mPa into round disks with a diameter of 1.6 cm and thickness of 0.2 mm.X-ray powder diffraction(XRD)patterns were recorded using a D/MAX-2200 diffractometer(Rigaku,Japan), equipped with a rotating anode and with a Cu Kαradiation source(λ=0.154178 nm).UV-Vis absorption spectra were obtained on a HITACHI U-3010 spectrophotometer.The standard UV absorption at 259 nm versus GCconcentration curve was obtained;the concentrations were determined by weighing the graphene in suspension.

    3 Results and discussion

    Fig.1 TEM images of graphene(a,b)TEM images of GPand GC,respectively;(c,d)HRTEM images show the folded edges of single-layer and bi-layer GCsheets,respectively. Black arrow points to single-layer nano graphene meshes,and white ones point to carbon nanocages.

    During the microwaving process,EG absorbed microwave energy efficiently and turned it into heat.Consequently,the temperature of EG rose quickly in a few seconds,and the interspacing between graphite layers was greatly expanded after microwaving(Scheme 1,bottom).Meanwhile,ferrocene in the mixture evaporated and intercalated into the expanded interspace of EG,where it decomposed and deposited iron nanoparticles(NPs)on the hot surface of EG.The typical HRTEM images of the GCsample are shown in Fig.1.As reported previously,11EG can also be expanded by microwaving in the absence of ferrocene,and then be exfoliated to produce graphene(GP) in organic solvents by sonication.For comparsion,the TEM image of GPis enclosed in Fig.1.GP(Fig.1a)shows featureless regions in the graphene sheet as reported,2while plenty of dark dots are observed on the GCsheets(Fig.1b).These scattered dots are pure carbon structure,since only carbon and copper (copper is from the supporting mesh)have been detected on the sheet by electron disperse X-ray spectroscopy(EDS)(see Fig.2).

    The folded edges of GCprovide signatures to indentify the layers of the graphene sheet.2The dark straight lines of the folded graphene in Figs.1c and 1d are signatures of folded single-layer and bi-layer graphene sheets,respectively.Interestingly,the folded edges of GCalso provide a perpendicular view of the decorated carbon islands.Nano graphene meshes(indicated by black arrows in Fig.1)and carbon nanocages(indicated by white arrows in Fig.1)can be identified.All these carbon nano-islands serve as permanent ripples on graphene sheets to stabilize the graphene.These carbon nanocages formed in the presence of small amount of ferrocene(Fig.1d)are single-layer cages.When the amount of ferrocene in the reaction mixture increases,the carbon nanocage grows bigger and consists of multiple layers(Fig.2a).

    Raman spectrum is widely used to determine the number of layers of graphene sheets.Fig.3a shows the Raman spectra of GC,GP,EG,and rGO.The IG/I2D(intensity ratio of G peak to 2D peak)of GPis very similar to that of EG,indicating that GPis not well exfoliated and exists mainly as multiple layers or graphite-like.This is consistent with the TEM investigation that thin-layer sheet of GPis rare.The IG/I2Dratio of GCis significantly smaller than that of GP,corresponding to thin-layer graphene sheets.12Compared with rGO,which shows a big D peak,there is a small D peak for GPand no D peak for GC,suggesting much less defect in GC.

    Fig.2 HRTEM(a,b)and EDS(c)of carbon nanocage on GC(a)carbon nanocage with iron NP inside(before washing with HCl solution); (b)after washing with HCl solution to remove the deposited iron NP, the white square indicates the EDS(c)detection area.

    Fig.3 (a)Raman spectra of expandable graphite(EG),rGO, GP,and GC;and(b)XRD patterns of GPand GC

    The decorated carbon nanoislands can increase the yield of suspensible and thin-layer graphene,and make the suspension more stable.In comparison,after one circle sonication and subsequent centrifugation,the yield we obtained is~17%(mass fraction)for suspensible GP,while up to~35%for GC.And 48 h after the suspension,the concentration of GCin NMP is about 0.045 mg·mL-1,which is about 5-fold more than that of GP(see Fig.4).

    Thermodynamically,the Gibbs free energy difference(ΔG) between the single-layer graphene sheets and the multilayer graphene/graphite can be calculated by ΔG=ΔH-TΔS.The reported transient ripple2on the single-layer graphene is an entropic term favourable for the single-layer graphene state.This might be one reason that graphite can be exfoliated by heating at above 1000°C.10Enthalpically,due to the unsaturated electronic valence,the single-layer graphene is unfavourable compared to the multiple-layer graphene and graphite.Overall, graphite,not the single-layer graphene,is the most stable state, thus graphene sheets tend to stack up.

    Fig.4 UV-Vis absorbance spectra of GCand GPInset shows the photos of the GCand GPsuspension.Curve a corresponds to the 4-fold diluted GPsample of the inset bottle a;Curve b corresponds to the 10-fold diluted GCsample of the inset bottle b.

    When the single-layer graphene sheets stack into bi-to multiple-layer sheets,the strong interactions between graphene layers make the stacked layers more and more rigid.This is why the transient ripples on bi-layer graphene sheets become smaller than that on single-layer ones,and disappear eventually on multiple-layer ones,according to the published results.2For the few-layer graphene,although it is enthalpically more favourable than the single-layer one,it loses the flexibility of the single-layer sheet(entropically unfavourable).

    For GC,the permanent ripples,namely carbon nanoislands, compensate the enthalpy of the single-layer graphene,and the scatterance feature of the nanoislands keeps the graphene sheet flexible.Therefore,GCis entropically favourable compared to GP.This may explain why GCis more stable than GPin suspension.

    It has to be pointed out that,in solution,there is also a big entropical penalty for the single-layer graphene sheet,originated from the ordering of solvent molecules when bounded to graphene sheets.The tighter the binding between the solvent molecule and graphene sheet is,the more ordered the solvent molecules around graphene sheets are,and the larger solvent entropical penalty is.This solvent entropical penalty might be the major driving force for the aggregation of graphene sheets in solution,as the hydrophic effect(solvent entropical penalty originated from the ordering of water molecules around hydrophobic amino acids)is the major driving force for the protein folding.32,33So,currently,there is no solvent that could dissolve graphene into stable solution.Without introducing repulsion force and reducing sticking between graphene sheets by chemical modification,thin-layer graphene sheets will eventually aggregate and precipitate.Therefore,a more realistic approach to prevent the aggregation and stacking of graphene sheet is not trying to find a better solvent,but trying to prevent the graphitization of the aggregates.Adding permanent sp2carbon ripples on graphene sheet is this kind of approach.It is superior to those functionalization methods,because it does not bring in exotic heteroatoms.Moreover,because of the lack of large area of perfect matching surfaces between permanently rippled graphene sheets,the permanent ripples would prevent the graphitization of GCprecipitates.Consequently,GCprecipitates are easily re-suspended by mild sonication,even compressing the GCprecipitates into bulk solid form,as depicted in Scheme 1. XRD results(Fig.3b)show that the area of the(002)peak of solid GCpowder is only about one-sixth of that of GP,indicating much less degree of crystallization(graphitization)for GC.

    One of the most amazing properties of graphene is its excellent electronic conductivity.However,the conductivity of graphene produced by the many reported solution-processable methods is very poor.Due to existence of a lot of oxygen content,the electronic conductivity of rGO is not good,usually in the order of 10-103S·m-1,depending on the reduction procedures.13-15,21,34,35Solvent-exfoliation of natural graphite can produce graphene of relatively high quality.Even so,the conductivity of the obtained graphene is just comparable to some rGO films,12much lower than expected for the“pristine graphene”. This is probably due to the fact that there are strong interactions between the graphene layers in graphite,thus the strong sonication treatment is necessary to exfoliate it.The strong sonication would produce many defects on the exfoliated graphene sheets,and then decrease the conductivity of the graphene.

    The expanded interlayer spacing of expanded graphite makes it easier to be exfoliated.Therefore,only much milder sonication is required to expand it.In comparison,at our mild sonication condition,the yield of suspensible graphene from the sonication of natural graphite powder is less than 2%,and no few-layer graphene has been identified.

    Milder sonication introduces less defect.As expected,GCshows excellent conductivity of~65000 S·m-1,which is about one order of magnitude higher than that of the above reported pristine graphene.12Since the data from different laboratories and different methods might be not comparable,we also prepared the hydrazine-reduced rGO and measured its conductivity as a reference.The measured conductivity for rGO is~140 S·m-1,which is in consistent with the reported values.15,21,34,35Interestingly,the conductivity of GCis also significantly higher than that of GP(~48000 S·m-1),which is produced at the exact sonicating condition.

    Fig.5 TEM image capturing the etching paths(outlined by red dotted-lines)on EG sheet by iron NPs and the formation of carbon nanocages around iron NPs(indicated by blue arrows)

    Since the microwave reaction completes too quickly to capture the intermediates of the reaction,we used a conventional CVD method to slow down the process and investigate the mechanism of the formation of the permanent rippled graphene structure.As shown by TEM image(Fig.5),the deposited iron NPs can etch the EG sheet and leave nano graphene meshes on the graphene sheets.Along the etching paths,those etched carbon atoms are dissolved in the iron NPs and eventually turned into carbon nanocages.During the producing process of GC, iron NPs might preferably deposit on the defects of EG,which are also the sites where the expansion of EG originates,so the defects might be more likely etched or eliminated.This is likely the mechanism for the decrease of defects in GC.

    The decrease of defects has been evidenced by XPS results (Fig.6a).Deconvolution of the C 1s peak shows that there are more than 88%sp2carbon atoms in GC,much higher than that of GP(73%).The rest peaks of GCmainly come from the residual NMP solvent molecules on graphene sample,which is consistent with the literature.12This result indicates little disordered carbon on GC,suggesting that almost all the decorated carbon nanoislands are sp2carbon structures.The defect decrease of GCis also evidenced by the FTIR spectra(Fig.6b) and thermogravimetric analysis(TGA)(Fig.6c).FTIR spectra show that GCis very similar to nature graphite,while GPcontains many oxygen-containing groups such as the peaks around 1090 cm-1(vC―O)and 1260 cm-1(vC―O―C).36TGA shows that GCis the most stable one,with 92%mass remaining after heating to 800°C,while the remained masses for GPand rGO are 86% and 77%,respectively.In addition,the absence of D peak at 1350 cm-1in Raman spectrum of GCindicates the less disordered carbon structure,demonstrating the high-quality of GC.

    Fig.6 Valency and stability of graphene prepared by different methods(a)XPS spectra of rGO,GP,and GC;(b)FTIR spectra of natural graphite,rGO,GP,and GC;(c)TGAcurves of rGO,GP,and GC

    4 Conclusions

    In summary,we report here a facile method to produce solution-processable graphene sheets from EG.The essence of this method is to stabilize graphene sheets and prevent their re-stacking by introducing permanent ripples on the graphene sheet,i.e.,decorating carbon nanoislands on the graphene sheets.Since the decorated nanoislands are sp2carbon structure as that of graphene sheet,they do not deteriorate the graphene and introduce heteroatoms into the system.Thus graphene provides an excellent electronic conductivity up to 65000 S·m-1. The permemantly rippled graphene is readily suspensible in NMP solvent with concentration up to 0.045 mg·mL-1,showing great potential in wide range of solution-processable applications of graphene.

    (1) Mermin,N.D.Phys.Rev.1968,176,250.doi:10.1103/ PhysRev.176.250

    (2)Meyer,J.C.;Geim,A.K.;Katsnelson,M.I.;Novoselov,K.S.; Booth,T.J.;Roth,S.Nature 2007,446,60.doi:10.1038/ nature05545

    (3) Novoselov,K.S.;Jiang,D.;Schedin,F.;Booth,T.J.; Khotkevich,V.V.;Morozov,S.V.;Geim,A.K.Proc.Natl. Acad.Sci.U.S.A.2005,102,10451.doi:10.1073/pnas. 0502848102

    (4) Fasolino,A.;Los,J.H.;Katsnelson,M.I.Nat.Mater.2007,6, 858.doi:10.1038/nmat2011

    (5) Geim,A.K.;Novoselov,K.S.Nat.Mater.2007,6,183.doi: 10.1038/nmat1849

    (6)Huang,X.;Yin,Z.Y.;Wu,S.X.;Qi,X.Y.;He,Q.Y.;Zhang,Q. C.;Yan,Q.Y.;Boey,F.;Zhang,H.Small 2011,7,1876.doi: 10.1002/smll.201002009

    (7) Geim,A.K.Science 2009,324,1530.doi:10.1126/science. 1158877

    (8) Jiang,H.J.Small 2011,7,2413.

    (9)Huang,X.;Qi,X.Y.;Boey,F.;Zhang,H.Chem.Soc.Rev.2012, 41,666.doi:10.1039/c1cs15078b

    (10)Li,X.L.;Zhang,G.Y.;Bai,X.D.;Sun,X.M.;Wang,X.R.; Wang,E.G.;Dai,H.J.Nat.Nanotechnol.2008,3,538.doi: 10.1038/nnano.2008.210

    (11) Liu,Z.;Fan,C.W.;Chen,L.;Cao,A.N.J.Nanosci.Nanotech. 2010,10,7382.doi:10.1166/jnn.2010.2780

    (12) Hernandez,Y.;Nicolosi,V.;Lotya,M.;Blighe,F.;Sun,Z.;De, S.;McGovern,I.T.;Holland,B.;Byrne,M.;Gunko,Y.;Boland, J.;Niraj,P.;Duesberg,G.;Krishnamurti,S.;Goodhue,R.; Hutchison,J.;Scardaci,V.;Ferrari,A.C.;Coleman,J.N.Nat. Nanotechnol.2008,3,563.

    (13) Eda,G.;Fanchini,G.;Chhowalla,M.Nat.Nanotechnol.2008, 3,270.doi:10.1038/nnano.2008.83

    (14) Li,D.;Muller,M.B.;Gilje,S.;Kaner,R.B.;Wallace,G.G. Nat.Nanotechnol.2008,3,101.doi:10.1038/nnano.2007.451

    (15)Cao,A.N.;Liu,Z.;Chu,S.S.;Wu,M.H.;Ye,Z.M.;Cai,Z. W.;Chang,Y.L.;Wang,S.F.;Gong,Q.H.;Liu,Y.F.Adv. Mater.2010,22,103.doi:10.1002/adma.v22:1

    (16) Qi,X.Y.;Pu,K.Y.;Zhou,X.Z.;Li,H.;Liu,B.;Boey,F.; Huang,W.;Zhang,H.Small 2010,6,663.doi:10.1002/ smll.v6:5

    (17) Stankovich,S.;Dikin,D.A.;Dommett,G.H.B.;Kohlhaas,K. M.;Zimney,E.J.;Stach,E.A.;Piner,R.D.;Nguyen,S.T.; Ruoff,R.S.Nature 2006,442,282.doi:10.1038/nature04969

    (18) Choucair,M.;Thordarson,P.;Stride,J.A.Nat.Nanotechnol. 2009,4,30.doi:10.1038/nnano.2008.365

    (19) Qi,X.Y.;Pu,K.Y.;Li,H.;Zhou,X.Z.;Wu,S.;Fan,Q.L.;Liu, B.;Boey,F.;Huang,W.;Zhang,H.Angew.Chem.Int.Edit. 2010,49,9426.doi:10.1002/anie.201004497

    (20) Feng,X.;Hu,G.;Hu,J.Nanoscale 2011,3,2099.doi:10.1039/ c1nr00004g

    (21)Dreyer,D.R.;Park,S.;Bielawski,C.W.;Ruoff,R.S.Chem. Soc.Rev.2010,39,228.doi:10.1039/b917103g

    (22) Park,S.;An,J.;Jung,I.;Piner,R.D.;An,S.J.;Li,X.S.; Velamakanni,A.;Ruoff,R.S.Nano Lett.2009,9,1593.doi: 10.1021/nl803798y

    (23) Dikin,D.A.;Stankovich,S.;Zimney,E.J.;Piner,R.D.; Dommett,G.H.B.;Evmenenko,G.;Nguyen,S.T.;Ruoff,R.S. Nature 2007,448,457.doi:10.1038/nature06016

    (24)Zhou,X.Z.;Huang,X.;Qi,X.Y.;Wu,S.X.;Xue,C.;Boey,F. Y.C.;Yan,Q.Y.;Chen,P.;Zhang,H.J.Phys.Chem.C 2009, 113,10842.doi:10.1021/jp903821n

    (25) Chang,Y.L.;Chen,S.;Cao,A.N.J.Shanghai University (Natural Science)2010,16(6),577.[常艷麗,陳 勝,曹傲能.上海大學(xué)學(xué)報(自然科學(xué)版),2010,16(6),577.]

    (26)Yang,S.T.;Chen,S.;Chang,Y.;Cao,A.;Liu,Y.;Wang,H. J.Colloid Interface Sci.2011,359,24.doi:10.1016/j.jcis. 2011.02.064

    (27)Yang,S.T.;Chang,Y.;Wang,H.;Liu,G.;Chen,S.;Wang,Y.; Liu,Y.;Cao,A.J.Colloid Interface Sci.2010,351,122.doi: 10.1016/j.jcis.2010.07.042

    (28)Chang,Y.;Yang,S.T.;Liu,J.H.;Dong,E.;Wang,Y.;Cao,A.; Liu,Y.;Wang,H.Toxicol Lett.2011,200,201.doi:10.1016/j. toxlet.2010.11.016

    (29)Hao,R.;Qian,W.;Zhang,L.;Hou,Y.Chem.Commun.2008, 6576.

    (30)Qian,W.;Cui,X.;Hao,R.;Hou,Y.;Zhang,Z.ACS Appl.Mater. Interfaces 2011,3(7),2259.doi:10.1021/am200479d

    (31)Qian,W.;Hao,R.;Hou,Y.;Tian,Y.;Shen,C.;Gao,H.;Liang, X.Nano Res.2009,2,706.doi:10.1007/s12274-009-9074-z

    (32) Kauzmann,W.Adv.Protein Chem.1959,14,1.doi:10.1016/ S0065-3233(08)60608-7

    (33) Dill,K.A.Biochemistry 1990,29,7133.doi:10.1021/ bi00483a001

    (34) Jung,I.;Dikin,D.A.;Piner,R.D.;Ruoff,R.S.Nano Lett. 2008,8,4283.doi:10.1021/nl8019938

    (35) Gomez-Navarro,C.;Weitz,R.T.;Bittner,A.M.;Scolari,M.; Mews,A.;Burghard,M.;Kern,K.Nano Lett.2007,7,3499. doi:10.1021/nl072090c

    (36) Si,Y.C.;Samulski,E.T.Nano Lett.2008,8,1679.doi:10.1021/ nl080604h

    July 23,2012;Revised:September 10,2012;Published on Web:September 10,2012.

    Solution-Processable,Highly Conductive,Permanently Rippled Graphene Sheets

    FAN Cheng-Wei ZHANG Xin CHEN Sheng WANG Hai-Fang CAO Ao-Neng*
    (Institute of Nanochemistry and Nanobiology,Shanghai University,Shanghai 200444,P.R.China)

    The single atom thick sp2carbon structure of graphene gives rise to its unique properties and potential applications.However,one serious obstacle for its application is that graphene is prone to aggregate in suspension and gradually stack into graphite.Here,we report a novel approach to solve this problem.The basic idea is to introduce sp2carbon nano-islands on the graphene sheets that act as permanent ripples to prevent the stacking and graphitization of graphene and make it easy to re-suspend. Unlike most functionalization methods,this approach avoids the introduction of heteroatoms.Thus,it does not deteriorate the structure and change the properties of graphene.The carbon-rippled graphene has a remarkable electronic conductivity of~65000 S·m-1,and can be readily suspended in solvent.

    Graphene;Ripple;Carbon nanocage;Expandable graphite;Conductivity; Solution stability

    10.3866/PKU.WHXB201209103

    ?Corresponding author.Email:ancao@shu.edu.cn;Tel:+86-21-66135277.

    The project was supported by the National Natural Science Foundation of China(21073117),National Key Basic Research Program of China(973) (2009CB930200,2011CB933402),and Shanghai LeadingAcademic Disciplines,China(S30109).

    國家自然科學(xué)基金(21073117),國家重點基礎(chǔ)研究發(fā)展規(guī)劃項目(973)(2009CB930200,2011CB933402)和上海市重點學(xué)科(S30109)資助

    O641

    猜你喜歡
    上海大學(xué)導(dǎo)電性波紋
    加入超高分子量聚合物的石墨烯纖維導(dǎo)電性優(yōu)異
    基于NACA0030的波紋狀翼型氣動特性探索
    小波紋的童話
    《上海大學(xué)學(xué)報(自然科學(xué)版)》征稿簡則
    上海大學(xué)學(xué)報(自然科學(xué)版)征稿簡則
    《上海大學(xué)學(xué)報(自然科學(xué)版)》征稿簡則
    為什么水面波紋蕩漾
    學(xué)與玩(2017年5期)2017-02-16 07:06:26
    PPy/Ni/NanoG復(fù)合材料的制備及導(dǎo)電性能研究
    中國塑料(2016年3期)2016-06-15 20:30:00
    碳納米管陣列/環(huán)氧樹脂的導(dǎo)熱導(dǎo)電性能
    TiO2對硫正極材料導(dǎo)電性能的影響
    午夜免费观看网址| 毛片女人毛片| 久久久久久国产a免费观看| 欧美性猛交╳xxx乱大交人| 国内毛片毛片毛片毛片毛片| 狠狠狠狠99中文字幕| 国产精品 国内视频| 免费看十八禁软件| 久久伊人香网站| 亚洲专区字幕在线| 久久久国产欧美日韩av| 免费观看人在逋| 午夜激情欧美在线| 日韩欧美在线乱码| 久久欧美精品欧美久久欧美| 成在线人永久免费视频| xxxwww97欧美| 99国产精品一区二区三区| 亚洲精品在线观看二区| 免费大片18禁| 精品午夜福利视频在线观看一区| 婷婷亚洲欧美| 国产蜜桃级精品一区二区三区| 91在线精品国自产拍蜜月 | 一本一本综合久久| 国产激情欧美一区二区| 身体一侧抽搐| 亚洲国产欧美人成| 精品一区二区三区四区五区乱码| 亚洲国产欧美网| 午夜福利高清视频| 天天添夜夜摸| 欧美丝袜亚洲另类 | 国产精品女同一区二区软件 | 国产精品香港三级国产av潘金莲| 夜夜爽天天搞| 级片在线观看| av在线蜜桃| 中文字幕人妻丝袜一区二区| 亚洲人成电影免费在线| 亚洲av片天天在线观看| 91av网一区二区| 香蕉丝袜av| 久久这里只有精品19| 亚洲av中文字字幕乱码综合| 亚洲av成人不卡在线观看播放网| 国产成人福利小说| bbb黄色大片| 可以在线观看毛片的网站| 悠悠久久av| 免费高清视频大片| 麻豆国产av国片精品| 两个人看的免费小视频| 久久久久久九九精品二区国产| www.999成人在线观看| 国产精华一区二区三区| 怎么达到女性高潮| 大型黄色视频在线免费观看| 国产一区二区三区在线臀色熟女| xxxwww97欧美| 亚洲av五月六月丁香网| 精品国产美女av久久久久小说| 中亚洲国语对白在线视频| 日本三级黄在线观看| 亚洲午夜精品一区,二区,三区| 国产精品香港三级国产av潘金莲| 美女cb高潮喷水在线观看 | 亚洲熟妇中文字幕五十中出| 18禁黄网站禁片午夜丰满| 看黄色毛片网站| 亚洲专区中文字幕在线| 黄色视频,在线免费观看| 国产麻豆成人av免费视频| 波多野结衣巨乳人妻| 女同久久另类99精品国产91| 香蕉av资源在线| 久久久久国内视频| 欧美最黄视频在线播放免费| 国内精品美女久久久久久| 精品乱码久久久久久99久播| bbb黄色大片| 天堂av国产一区二区熟女人妻| 男人舔女人的私密视频| 极品教师在线免费播放| 亚洲av电影不卡..在线观看| 国产亚洲精品久久久久久毛片| 免费电影在线观看免费观看| 久99久视频精品免费| 99国产精品99久久久久| 婷婷精品国产亚洲av在线| 国产一区二区三区在线臀色熟女| 99久久精品国产亚洲精品| 又黄又粗又硬又大视频| 久久精品国产清高在天天线| 俺也久久电影网| 国产av一区在线观看免费| 亚洲精品一卡2卡三卡4卡5卡| 香蕉av资源在线| 久久久色成人| 欧美日韩国产亚洲二区| 九九久久精品国产亚洲av麻豆 | 一个人看视频在线观看www免费 | 精品欧美国产一区二区三| 啦啦啦韩国在线观看视频| 日本免费一区二区三区高清不卡| 一夜夜www| 成熟少妇高潮喷水视频| 亚洲精品在线美女| 亚洲性夜色夜夜综合| 成年女人毛片免费观看观看9| 欧美不卡视频在线免费观看| 长腿黑丝高跟| 久久久久国产一级毛片高清牌| 国产精品一区二区三区四区免费观看 | 大型黄色视频在线免费观看| 国产成人精品无人区| 色尼玛亚洲综合影院| 亚洲人成网站在线播放欧美日韩| 亚洲精品美女久久久久99蜜臀| 国产成人aa在线观看| 99国产精品99久久久久| 亚洲片人在线观看| 亚洲人成电影免费在线| 老熟妇乱子伦视频在线观看| 欧美黑人欧美精品刺激| 欧美3d第一页| 国产视频一区二区在线看| 亚洲18禁久久av| 熟女人妻精品中文字幕| 国产精品一区二区三区四区免费观看 | 床上黄色一级片| 午夜激情福利司机影院| 国产毛片a区久久久久| 国产精品久久久人人做人人爽| 给我免费播放毛片高清在线观看| 国产伦一二天堂av在线观看| 亚洲激情在线av| 欧美色视频一区免费| 亚洲午夜理论影院| 亚洲美女视频黄频| 热99re8久久精品国产| 欧美乱色亚洲激情| 深夜精品福利| aaaaa片日本免费| 久久久久国产精品人妻aⅴ院| 香蕉av资源在线| 久99久视频精品免费| 国产精品亚洲美女久久久| 精品国产三级普通话版| 一进一出抽搐动态| 亚洲色图av天堂| 97超视频在线观看视频| 亚洲一区高清亚洲精品| 亚洲国产高清在线一区二区三| 国产成人福利小说| www.精华液| 精品国产亚洲在线| 欧美日韩乱码在线| 精品久久久久久久久久免费视频| 国产精品久久久av美女十八| av女优亚洲男人天堂 | 久久天躁狠狠躁夜夜2o2o| 怎么达到女性高潮| 在线观看一区二区三区| 操出白浆在线播放| 黄色成人免费大全| 天天添夜夜摸| 国产高清三级在线| 亚洲欧美日韩无卡精品| 国产淫片久久久久久久久 | 首页视频小说图片口味搜索| 亚洲 欧美 日韩 在线 免费| 制服丝袜大香蕉在线| 欧洲精品卡2卡3卡4卡5卡区| 婷婷精品国产亚洲av在线| 51午夜福利影视在线观看| 国产又黄又爽又无遮挡在线| 91av网一区二区| 黄片大片在线免费观看| 久久久久久久久中文| 午夜a级毛片| 99在线视频只有这里精品首页| 国产伦在线观看视频一区| 国产精品av视频在线免费观看| 欧美色视频一区免费| 亚洲专区字幕在线| 国产午夜精品久久久久久| 欧美3d第一页| 国产精品综合久久久久久久免费| 母亲3免费完整高清在线观看| 日韩大尺度精品在线看网址| av欧美777| av女优亚洲男人天堂 | 日本一二三区视频观看| 好看av亚洲va欧美ⅴa在| 国产蜜桃级精品一区二区三区| 精品熟女少妇八av免费久了| 国产精品亚洲一级av第二区| 91av网站免费观看| 99精品在免费线老司机午夜| 草草在线视频免费看| 国产真实乱freesex| 欧美绝顶高潮抽搐喷水| 亚洲精品美女久久av网站| www国产在线视频色| 熟女电影av网| 欧美成人性av电影在线观看| 日韩欧美在线乱码| 国产精品一区二区三区四区久久| 蜜桃久久精品国产亚洲av| 我的老师免费观看完整版| 黄频高清免费视频| 天堂av国产一区二区熟女人妻| 男女下面进入的视频免费午夜| 精品一区二区三区视频在线 | 国产黄a三级三级三级人| 亚洲欧美精品综合久久99| 亚洲一区二区三区色噜噜| 欧美日韩乱码在线| 小蜜桃在线观看免费完整版高清| 免费电影在线观看免费观看| 欧美另类亚洲清纯唯美| 国产男靠女视频免费网站| 久久久久国内视频| 国内精品一区二区在线观看| 九色成人免费人妻av| 成人三级做爰电影| 国产男靠女视频免费网站| 俺也久久电影网| 国产人伦9x9x在线观看| 日韩中文字幕欧美一区二区| 一进一出好大好爽视频| 在线a可以看的网站| 亚洲中文日韩欧美视频| 亚洲国产精品合色在线| 又黄又爽又免费观看的视频| 97人妻精品一区二区三区麻豆| 免费观看人在逋| 久久精品国产99精品国产亚洲性色| 无限看片的www在线观看| av国产免费在线观看| 欧美成人性av电影在线观看| 人妻久久中文字幕网| 国产精品乱码一区二三区的特点| 欧美日本亚洲视频在线播放| 久久中文字幕人妻熟女| 午夜激情福利司机影院| 黑人操中国人逼视频| 亚洲真实伦在线观看| 久久久久久久精品吃奶| 美女被艹到高潮喷水动态| 婷婷六月久久综合丁香| 老司机福利观看| 久久久久久九九精品二区国产| 亚洲七黄色美女视频| 日韩欧美在线二视频| 99在线视频只有这里精品首页| 成人av在线播放网站| 中文字幕精品亚洲无线码一区| 精品一区二区三区av网在线观看| 亚洲色图av天堂| 精品国产美女av久久久久小说| 免费观看的影片在线观看| 99热这里只有是精品50| 国产精品综合久久久久久久免费| 色综合站精品国产| xxxwww97欧美| 又黄又爽又免费观看的视频| 日韩欧美一区二区三区在线观看| 99riav亚洲国产免费| 国产成人av激情在线播放| 免费在线观看影片大全网站| 色综合站精品国产| 久久久国产成人精品二区| 激情在线观看视频在线高清| 观看美女的网站| 精品国内亚洲2022精品成人| 99热只有精品国产| 在线播放国产精品三级| av欧美777| 夜夜夜夜夜久久久久| 国产精品久久久久久久电影 | 国产精品 国内视频| 好看av亚洲va欧美ⅴa在| 长腿黑丝高跟| 午夜精品一区二区三区免费看| 久久亚洲精品不卡| 熟女少妇亚洲综合色aaa.| 婷婷精品国产亚洲av在线| 一本一本综合久久| 欧美三级亚洲精品| 十八禁人妻一区二区| 国内精品一区二区在线观看| 男女之事视频高清在线观看| 国产精品99久久久久久久久| 国内毛片毛片毛片毛片毛片| 91九色精品人成在线观看| 国产午夜精品久久久久久| 观看免费一级毛片| 黄片小视频在线播放| 日韩欧美在线二视频| 亚洲国产精品999在线| 无人区码免费观看不卡| 日韩人妻高清精品专区| 别揉我奶头~嗯~啊~动态视频| 熟女电影av网| 一本久久中文字幕| 夜夜看夜夜爽夜夜摸| 最近最新免费中文字幕在线| 国产精品98久久久久久宅男小说| 母亲3免费完整高清在线观看| 熟妇人妻久久中文字幕3abv| 91av网站免费观看| 国产成+人综合+亚洲专区| 亚洲无线在线观看| 波多野结衣巨乳人妻| 亚洲精品美女久久久久99蜜臀| 中文在线观看免费www的网站| 色噜噜av男人的天堂激情| 欧美黄色淫秽网站| 国产男靠女视频免费网站| 99久久国产精品久久久| 欧美一区二区精品小视频在线| 久久久久九九精品影院| 国产精品亚洲一级av第二区| 日韩高清综合在线| 女同久久另类99精品国产91| 99riav亚洲国产免费| 黄色日韩在线| 中亚洲国语对白在线视频| 又黄又爽又免费观看的视频| 日韩av在线大香蕉| 国产精品一区二区精品视频观看| 99久久无色码亚洲精品果冻| 曰老女人黄片| 久久亚洲真实| 久久国产精品影院| 这个男人来自地球电影免费观看| 亚洲熟女毛片儿| 国模一区二区三区四区视频 | 最近在线观看免费完整版| 国产精品久久久久久久电影 | 九色国产91popny在线| 久久亚洲精品不卡| 在线播放国产精品三级| 国产精品,欧美在线| svipshipincom国产片| 亚洲成人中文字幕在线播放| 一卡2卡三卡四卡精品乱码亚洲| av天堂在线播放| 99在线视频只有这里精品首页| 动漫黄色视频在线观看| 男人和女人高潮做爰伦理| 日韩中文字幕欧美一区二区| 男人和女人高潮做爰伦理| 成年女人看的毛片在线观看| tocl精华| ponron亚洲| 成年人黄色毛片网站| 欧美三级亚洲精品| 一级作爱视频免费观看| 亚洲专区中文字幕在线| 亚洲人成伊人成综合网2020| 午夜免费成人在线视频| 夜夜夜夜夜久久久久| 国产野战对白在线观看| 亚洲精品456在线播放app | 在线播放国产精品三级| 美女黄网站色视频| 精品国产乱子伦一区二区三区| 天堂动漫精品| 一级毛片精品| 噜噜噜噜噜久久久久久91| 色综合婷婷激情| 精品久久久久久久毛片微露脸| 一级毛片高清免费大全| 久久久精品欧美日韩精品| 亚洲午夜理论影院| 搡老妇女老女人老熟妇| 日韩高清综合在线| 黄色日韩在线| 免费观看的影片在线观看| 精品一区二区三区视频在线观看免费| 麻豆国产av国片精品| 一区二区三区高清视频在线| 在线免费观看不下载黄p国产 | 亚洲男人的天堂狠狠| 日本 av在线| svipshipincom国产片| 国产蜜桃级精品一区二区三区| 日本在线视频免费播放| 岛国视频午夜一区免费看| 夜夜躁狠狠躁天天躁| 99在线人妻在线中文字幕| 国产精品电影一区二区三区| 在线永久观看黄色视频| 国产日本99.免费观看| 色老头精品视频在线观看| 级片在线观看| 一区二区三区激情视频| 亚洲精品国产精品久久久不卡| 亚洲精品456在线播放app | 日韩欧美 国产精品| 欧美激情在线99| 久久精品国产综合久久久| 88av欧美| 欧美另类亚洲清纯唯美| 此物有八面人人有两片| 青草久久国产| 欧美不卡视频在线免费观看| 最近视频中文字幕2019在线8| 亚洲av成人精品一区久久| 少妇丰满av| 亚洲成a人片在线一区二区| 黄色 视频免费看| 久久天躁狠狠躁夜夜2o2o| 久久香蕉精品热| 香蕉国产在线看| 12—13女人毛片做爰片一| 女警被强在线播放| 在线视频色国产色| 色尼玛亚洲综合影院| 日韩欧美三级三区| 亚洲在线自拍视频| 午夜a级毛片| 久久久国产成人免费| 午夜福利视频1000在线观看| 国产亚洲精品av在线| 国产精品,欧美在线| 久久久国产成人精品二区| 亚洲精品在线美女| 亚洲国产欧美一区二区综合| 91九色精品人成在线观看| 久久久水蜜桃国产精品网| 久久久久精品国产欧美久久久| 神马国产精品三级电影在线观看| 最近在线观看免费完整版| 欧美日韩综合久久久久久 | 美女高潮喷水抽搐中文字幕| 99久久综合精品五月天人人| 亚洲精品在线观看二区| 国产欧美日韩一区二区精品| 亚洲精华国产精华精| av视频在线观看入口| 亚洲专区字幕在线| 黄频高清免费视频| 国产精品野战在线观看| 天堂动漫精品| 亚洲第一电影网av| 一a级毛片在线观看| 两人在一起打扑克的视频| 麻豆久久精品国产亚洲av| 麻豆av在线久日| 亚洲av五月六月丁香网| 国产伦人伦偷精品视频| 成人永久免费在线观看视频| 99国产综合亚洲精品| 丁香六月欧美| 十八禁网站免费在线| 级片在线观看| 亚洲美女视频黄频| 亚洲欧美精品综合久久99| 久久久国产欧美日韩av| 97超级碰碰碰精品色视频在线观看| 成人av一区二区三区在线看| 男人的好看免费观看在线视频| 一级黄色大片毛片| 免费搜索国产男女视频| 亚洲国产精品合色在线| 亚洲欧美一区二区三区黑人| 亚洲av中文字字幕乱码综合| 中文字幕熟女人妻在线| 曰老女人黄片| 久久亚洲真实| 一二三四在线观看免费中文在| 日韩高清综合在线| 日韩欧美国产一区二区入口| 法律面前人人平等表现在哪些方面| 在线免费观看的www视频| 精品久久久久久久人妻蜜臀av| 91在线精品国自产拍蜜月 | 欧美又色又爽又黄视频| 欧美另类亚洲清纯唯美| 国产av不卡久久| 又黄又粗又硬又大视频| 亚洲五月婷婷丁香| 男女午夜视频在线观看| av黄色大香蕉| 精品久久久久久久毛片微露脸| 激情在线观看视频在线高清| 麻豆成人午夜福利视频| 美女免费视频网站| 夜夜躁狠狠躁天天躁| 偷拍熟女少妇极品色| 网址你懂的国产日韩在线| 后天国语完整版免费观看| 亚洲美女黄片视频| 中文在线观看免费www的网站| 色综合站精品国产| 一个人看的www免费观看视频| 一本一本综合久久| 亚洲国产精品999在线| 国产aⅴ精品一区二区三区波| a级毛片a级免费在线| 亚洲色图av天堂| 99精品久久久久人妻精品| 97人妻精品一区二区三区麻豆| 久久热在线av| 黄色视频,在线免费观看| 在线观看66精品国产| 18禁黄网站禁片午夜丰满| 少妇丰满av| 啦啦啦韩国在线观看视频| 日本a在线网址| 精品国产超薄肉色丝袜足j| 色视频www国产| 国产欧美日韩一区二区三| 日韩欧美在线乱码| 成人无遮挡网站| 久久精品人妻少妇| www.熟女人妻精品国产| 露出奶头的视频| 亚洲欧美精品综合一区二区三区| 午夜激情欧美在线| 他把我摸到了高潮在线观看| 久久久久久久久中文| 国产精品 国内视频| 久久精品人妻少妇| 国内久久婷婷六月综合欲色啪| 久久久久久国产a免费观看| 白带黄色成豆腐渣| 欧美日韩福利视频一区二区| 国内揄拍国产精品人妻在线| 精品久久久久久久人妻蜜臀av| 亚洲黑人精品在线| 伊人久久大香线蕉亚洲五| svipshipincom国产片| 淫秽高清视频在线观看| 黑人巨大精品欧美一区二区mp4| 很黄的视频免费| 黄色女人牲交| 亚洲国产日韩欧美精品在线观看 | 久久热在线av| 性色av乱码一区二区三区2| 日本黄大片高清| 精品久久蜜臀av无| 99在线人妻在线中文字幕| 激情在线观看视频在线高清| 女警被强在线播放| 免费av毛片视频| 搡老熟女国产l中国老女人| 日本一二三区视频观看| 97人妻精品一区二区三区麻豆| 麻豆成人午夜福利视频| 五月伊人婷婷丁香| 日日摸夜夜添夜夜添小说| 免费人成视频x8x8入口观看| 午夜福利高清视频| 亚洲第一电影网av| 亚洲九九香蕉| 亚洲精品在线美女| 色av中文字幕| 亚洲无线在线观看| 全区人妻精品视频| 精品久久蜜臀av无| 女生性感内裤真人,穿戴方法视频| 国产黄片美女视频| 老司机午夜十八禁免费视频| 丰满人妻一区二区三区视频av | 在线十欧美十亚洲十日本专区| 亚洲国产色片| 国产精品av视频在线免费观看| 亚洲国产欧美网| 男插女下体视频免费在线播放| 国产成人系列免费观看| 成人欧美大片| 成人无遮挡网站| 久久国产乱子伦精品免费另类| 亚洲人成网站高清观看| 欧美成人性av电影在线观看| 久久精品人妻少妇| 观看免费一级毛片| 岛国在线免费视频观看| 欧美+亚洲+日韩+国产| 中文在线观看免费www的网站| 黄频高清免费视频| 日韩人妻高清精品专区| 中文在线观看免费www的网站| 国产伦人伦偷精品视频| 久久久久久九九精品二区国产| 亚洲第一电影网av| 欧美日韩乱码在线| 国产爱豆传媒在线观看| 国产人伦9x9x在线观看| 男女之事视频高清在线观看| 我的老师免费观看完整版| e午夜精品久久久久久久| 国产高清激情床上av| 脱女人内裤的视频| 亚洲欧美日韩卡通动漫| 国产精品影院久久| 中文在线观看免费www的网站| 一夜夜www| 又粗又爽又猛毛片免费看| 色尼玛亚洲综合影院| 亚洲精品粉嫩美女一区| 超碰成人久久| 久久性视频一级片| 午夜福利欧美成人| 少妇的逼水好多| 国产精品久久久久久人妻精品电影| 日韩中文字幕欧美一区二区| 很黄的视频免费| 免费高清视频大片| 麻豆成人av在线观看|