Applied Catalysis B:Environmental 136–137 (2013) 94–102
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Applied Catalysis B:
Environmental
j o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /a p c a t
b
A high ef?cient photocatalyst Ag 3VO 4/TiO 2/graphene nanocomposite with wide spectral response
Jinxiu Wang,Peixian Wang,Yuantao Cao,Jing Chen,Wenjuan Li,Yu Shao,Yi Zheng,Danzhen Li ?
Research Institute of Photocatalysis,State Key Laboratory Breeding Base of Photocatalysis,Fuzhou University,Fuzhou 350002,PR China
a r t i c l e
i n f o
Article history:
Received 2December 2012
Received in revised form 27January 2013Accepted 3February 2013
Available online 13 February 2013
Keywords:
Visible light photocatalyst Ag 3VO 4TiO 2
Graphene
Heterojunction
a b s t r a c t
Great efforts have been made to develop ef?cient visible light activated photocatalysts in recent years.In this work,Ag 3VO 4/TiO 2/graphene nanocomposite as a wide spectrum responsive photocatalyst was prepared ?rst by a two-step process,which exhibited obviously increased visible light absorption and photocatalytic activity in degradation of organic pollutants including methyl orange and Rhodamine B,compared with Ag 3VO 4/TiO 2and TiO 2/GR nanocomposites.For Ag 3VO 4/TiO 2/graphene nanocomposite,the introduction of graphene contributed to the uniform dispersion of Ag 3VO 4and TiO 2nanoparticles on graphene sheets.The capacity of graphene in storing and shuttling electrons and the formation of hetero-junction between Ag 3VO 4and TiO 2facilitated together the enhancement of ef?ciency in the separation of photogenerated electron–hole pairs.Based on the results of photoelectrochemical measurement and the detection of active species in photocatalytic degradation process,the transfer of photogenerated carriers and photocatalytic degradation mechanism on Ag 3VO 4/TiO 2/graphene nanocomposite were proposed and discussed in detail.
? 2013 Elsevier B.V. All rights reserved.
1.Introduction
Heterogeneous photocatalysis by use of semiconductor mate-rials has been applied as an ef?cient method in the ?eld of environmental puri?cation.TiO 2nanoparticle photocatalysts are generally believed to be the most reliable material for the degra-dation of organic compounds due to their non-toxicity,low cost,physical and chemical stability and high reactivity [1,2].Sun light radiation consists of about 5%UV light,47%visible light and 48%infrared radiation.Unfortunately,TiO 2as the benchmark of UV photocatalysts is inactive under visible light due to its wide band gap [3].Moreover,the photogenerated electrons and holes in the excited states playing a very important role in pollutant degrada-tion are unstable and can be easily recombined,which results in low ef?ciency of photocatalysis [4].Therefore,TiO 2cannot make use of the vast potential of solar photocatalysis.
Up to now,a variety of strategies have been employed to nar-row its band gap and enhance the visible light photocatalytic performance via either doping [5–9]or modi?cation [10–12]or semiconductor coupling [13–18].Coupling of TiO 2with narrow band gap semiconductors as sensitizers which are capable of absorbing visible light has been proved to be a feasible approach.
?Corresponding author.Tel.:+8659183779256;fax:+8659183779256.E-mail addresses:dzli@https://www.doczj.com/doc/3314093155.html, ,danzli@https://www.doczj.com/doc/3314093155.html, (D.Li).
In recent years,tremendous efforts including the work of our team have been devoted to the formation of heterojunction between TiO 2and narrow band gap semiconductors to develop visible light responding photocatalyst with high activity [19–21].The formation of heterojunction between TiO 2and a narrow band gap semicon-ductor with a more negative conducting band (CB)level can result in the injection of CB electrons from narrow band gap semiconduc-tor to TiO 2,which is helpful for electron–hole separation [22–24].However,for the design of highly ef?cient heterojunction photo-catalyst,besides the demand of a commonsensible matching ability of band potentials between semiconductors,the smooth and spa-tially available transfer of charge (electron and hole)at the interface and the high electron and hole mobility of the semiconductors are signi?cant to increase the photocatalytic activity [25].For some heterojunction photocatalyst materials prepared by common wet chemical methods,the low proportion of effective structural ele-ments with intimate contact interface and the high degree of lattice mismatch between two semiconductors decrease the ef?ciency of the transfer and separation of photogenerated carriers (electron and hole).
The introduction of graphene provides a feasible approach to solve the problem to some extent.Recently,functionalized graphene-based semiconductor photocatalysts have attracted a lot of attention due to their high electron conductivity,large spe-ci?c surface area and adsorption [26].Many efforts are put into the synthesis of TiO 2–graphene nanocomposite [27–29].Bene?ting
0926-3373/$–see front matter ? 2013 Elsevier B.V. All rights reserved.https://www.doczj.com/doc/3314093155.html,/10.1016/j.apcatb.2013.02.010
J.Wang et al./Applied Catalysis B:Environmental136–137 (2013) 94–10295
from the high speci?c surface area,graphene emerged as a good support to make the loaded nanoparticles to achieve a uniform distribution without aggregation[27].The enhancement of pho-tocatalytic activity for TiO2–graphene nanocomposite is ascribed to the giant two-dimensional planar graphene structure favouring dye absorption,and suppressed electron–hole recombination due to the high electrical conductivity[30].Furthermore,incorpora-tion of two or more catalyst particles onto an individual graphene sheet at separate sites can provide greater versatility in carrying out selective catalytic or sensing processes and modify the structure and morphology of photocatalysts to enhance their photocatalytic performances[31–35].
In this study,incorporation of Ag3VO4with narrow gap band (2.2eV)[36]and TiO2onto graphene sheet was carried out?rstly to obtain Ag3VO4/TiO2/graphene nanocomposite.The composite of Ag3VO4and TiO2semiconductors with appropriate oxidation reduction energy levels could enhance the charge separation by the formation of heterojunction between them and engender its wide spectral response by extension of light absorption to the visible region.The introduction of graphene as a good support made the loaded Ag3VO4and TiO2nanoparticles achieve a uni-form distribution and further enhanced the charge separation and suppressed electron–hole recombination.The expected enhanced photocatalytic activity of Ag3VO4/TiO2/graphene nanocomposite was tested by degradation of organic pollutants(methyl orange and Rhodamine B).The photocatalytic mechanism for degradation of organic pollutants on Ag3VO4/TiO2/graphene was discussed in detail.
2.Experiment
2.1.Preparation
2.1.1.Synthesis of graphene oxide(GO)
GO nanosheets were prepared by chemical exfoliation of puri-?ed natural graphite powder by using a modi?ed Hummers and Offeman method[37,38].The concrete procedure of preparation was as follows.Firstly,10g of graphite powder(supplied by Qing-dao Haida Graphite CO.,Ltd.,China)was added to the cooled(0?C) mixture of230mL of concentrated H2SO4and60mL of concen-trated HNO3under vigorous mechanical stirring.Secondly,30g KMnO4was slowly added with stirring and the temperature of above mixture was to be cooled below20?C by an external ice bath.Successively,the mixture was stirred at35?C for2h.Thirdly, 500mL of distilled water was slowly added to the mixture,result-ing that the temperature increased to98?C and maintained at the temperature for30min.Finally,1.4L water was poured quickly into the system so as to terminate the reaction and20mL10%hydro-gen peroxide was added to reduce the residual permanganate and manganese dioxide.The suspension was separated and washed repeatedly by centrifugation with5%HCl solution and water to remove sulfate.The products were dialyzed for a week and dried in a vacuum oven at60?C to obtain the relatively pure GO.
2.1.2.Synthesis of TiO2/graphene(TiO2/GR)
40mg of GO was dispersed in15mL of absolute alcohol by ultra-sound and stirring to obtain brown suspension which is poured into a50mL Te?on-lined stainless autoclave.Then,5mL of tita-nium tetrabutoxide(Ti(OC4H9)4)was added to the autoclave and the mixture was stirred for1h.After that,1mL of concentrated hydrochloric acid was added dropwise to the above mixture. Finally,the autoclave underwent a hydrothermal process at180?C for36h,followed by cooling down to room temperature naturally. The products were harvested by centrifugation and washed several times with a mixture of ethanol and deionized water.After drying in air at60?C for12h,the TiO2/graphene(TiO2/GR)nanocomposite was obtained.Pure TiO2also can be prepared by the same method in the absence of GO.
2.1.
3.Synthesis of Ag3VO4/TiO2/graphene(Ag3VO4/TiO2/GR)
0.1598g of TiO2/GR powder was dispersed in60mL of12.5M AgNO3solution by ultrasound for1h and stirring for1.5h.Then, 20mL of12.5M NH4VO3was poured into the suspension and2M NaOH was used to adjust the pH value of the whole system to9. After stirring at800rpm for2h,the product was centrifugated and washed with distilled water for several times.The?nal solid prod-uct was slightly dried by cool air and then completely dried at60?C for12h to obtain Ag3VO4/TiO2/GR nanocomposite.Ag3VO4/TiO2 composite was gained when the TiO2/GR was replaced by TiO2in the above synthesis procedure.Ag3VO4was obtained in the absence of TiO2/GR by the same method.
2.2.Characterization
X-ray diffraction(XRD)patterns were measured by a Bruker D8 Advance X-ray diffractometer at40kV and40mA with Ni-?ltered Cu K?https://www.doczj.com/doc/3314093155.html,ser Raman spectra were recorded at room tem-perature on a Renishaw inVia Raman system and the laser line at 785nm was used as an excitation source.Transmission electron microscopy(TEM)images were obtained by using a FEI Tecnai G2 F20instrument operated at an accelerating voltage of200kV.Field emission scanning electron microscopy(FE-SEM)images were gained from a FEI Nova NanoSEM230instrument.UV-vis diffuse re?ectance spectra(DRS)were collected by a Varian Cary500 Scan UV-vis-NIR spectrometer with BaSO4as the background.The Brunauer–Emmett–Teller(BET)speci?c surface area and porosities of the samples were measured on a Micromeritics ASAP2020ana-lyzer by N2adsorption at77K.X-ray photoelectron spectroscopy (XPS)analysis was collected on a ESCALAB250photoelectron spectrometer(Thermo Fisher Scienti?c)with monochromatic Al K?radiation(E=1486.2eV).The photoelectrochemical data was collected by a CHI-660D electrochemical workstation(CH Instru-ments,USA).The photoelectrochemical experiment was carried out in a conventional three-electrode cell with a quartz window. The sample was deposited on a sheet of indium-tin-oxide(ITO) glass to serve as the working electrode with0.5cm×0.5cm area.A platinum wire and an Ag/AgCl electrode were used as the counter and reference electrodes,respectively.The electrolyte was0.1M Na2SO4solution.The detection of activated species was conducted by the spin-trapping electron spin resonance(ESR)measurement on a Bruker model A300spectrometer.The settings were as follows: center?eld,3512G;microwave frequency,9.86GHz;microwave power,20mW.
2.3.Tests of photocatalytic activity
The photocatalytic degradation of methyl orange(MO)or Rho-damine B(RhB)as model reactions[39–43]was carried out in an aqueous solution at ambient temperature controlled by an air-cooling system.The light source was a500W Xe-arc lamp(Institute of Electric Light Source,Beijing).The420and800nm cutoff?lters were placed in front of the vessel to ensure that the reactor was irradiated only by visible light ranging from420nm to800nm. When only800nm cutoff?lter was used,the simulated solar light ranging from320nm to800nm was obtained.The transmission spectra of420and800nm combined cutoff?lters,800nm cutoff ?lters and the100mL-Pyrex glass vessel were shown in Fig.S1(in Supplementary data).A total of0.08g of photocatalyst was added to80mL of simulating pollutant solution,such as MO solution (1×10?5g/L,10ppm)or RhB solution(1×10?5mol/L,10ppm), contained in a100mL Pyrex glass vessel with a plane side.Before
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Fig.1.(A)XRD patterns (the heart and club shape were used to stand for anatase TiO 2and Ag 3VO 4in the ?gure)and (B)Raman spectra of the synthesized samples.
irradiation,the suspension was magnetically stirred for 1h in the dark in order to reach adsorption–desorption equilibrium between the catalyst and the simulating pollutant.3mL aliquots were sam-pled and centrifuged to remove the catalyst at given time intervals.Then the supernatants were analyzed to study the photocatalytic degradation of the target pollutants by using Varian Cary 50UV-vis spectrophotometer.
3.Results and discussion
3.1.Physicochemical properties of Ag 3VO 4/TiO 2/GR
https://www.doczj.com/doc/3314093155.html,ponent and structure
XRD patterns providing information on the crystalline nature of a series of samples were presented in Fig.1A.The XRD pat-tern of TiO 2/GR nanocomposite was similar to that of as-prepared pure TiO 2as the comparison which completely corresponded to anatase crystalline phase TiO 2(JCPDS 21-1272).The synthesized Ag 3VO 4as the comparison was in accord with monoclinic ?-Ag 3VO 4(JCPDS 43-0542).The characteristic diffraction peaks of monoclinic ?-Ag 3VO 4and anatase TiO 2were obviously present in the XRD pattern of Ag 3VO 4/TiO 2/GR which is similar to that of Ag 3VO 4/TiO 2.Notably,no typical diffraction peaks belonging to the separate graphene (GR)were observed in the TiO 2/GR and Ag 3VO 4/TiO 2/GR nanocomposites.It has been previously reported that GO could be hydrothermally reduced to graphene in ethanol in a sealed autoclave [38].Then,the absence of such peak correspond-ing to GR can be ascribed to the fact that the main characteristic peak of GR might be shielded by the main peak of anatase TiO 2[44].Raman spectroscopic measurement was conducted to further elucidate the components of Ag 3VO 4/TiO 2/GR nanocomposite.As indicated in Fig.1B,the peaks located at 145cm ?1and 787cm ?1present in Raman spectrum of Ag 3VO 4/TiO 2/GR corresponded to the main peaks of TiO 2(Fig.S2)and Ag 3VO 4,respectively.The other two peaks appearing in Raman spectrum of Ag 3VO 4/TiO 2/GR belonged to D band and G band of GR.The D band is due to the breathing modes of sp 2atoms in rings and is related to the occurrence of defects and structural disorder in graphene sheets.The G band is derived from the stretching of the sp 2-hybridized carbon–carbon bonds and is highly sensitive to strain effects in sp 2system within graphene sheets [35].The analysis of Raman spectra combined with the results of XRD further con?rmed the presence of three components in Ag 3VO 4/TiO 2/GR nanocomposite.
The morphology of prepared TiO 2/GR,Ag 3VO 4/TiO 2and Ag 3VO 4/TiO 2/GR was observed with SEM (Fig.S3).The SEM image
of Ag 3VO 4/TiO 2composite (Fig.S3C)showed that there was no sheet-like structure when GR was absent.However,it was easy to observe many crumpled platelets decorated with nanoparticles in TiO 2/GR (Fig.S3A and B)and Ag 3VO 4/TiO 2/GR composite (Fig.S3D–F).Especially Fig.S3F showed a sheet of graphene with typical wrinkles and attached particles.It was believed that the observed crumpled sheets in Fig.S3were graphene sheets.TiO 2and Ag 3VO 4both densely deposited on surface and the edge of the corrugated graphene sheets in Ag 3VO 4/TiO 2/GR composite (Fig.S3D–F)and the morphology changed little compared with TiO 2/GR (Fig.S3A and B).The sizes of the composite sheets were in micrometer scale both in length and width,which allows an easy separation from the reaction system by conventional ?ltration.The forma-tion and structure of Ag 3VO 4/TiO 2/GR nanocomposite was further con?rmed by TEM analysis,and the representative images were shown in Fig.2.The obvious edges and crumpled silk waves of these graphene sheets (the locations which the arrows pointed at)shown in Fig.2A and C led us to believe that these nanopar-ticles were indeed deposited on the almost transparent graphene sheets as the support.As shown in Fig.2A,TiO 2nanoparticles were uniformly dispersed on graphene sheets by hydrothermal treatment.By further processing,Ag 3VO 4and TiO 2with differ-ent sizes and contrasts were both deposited on graphene sheets (Fig.2C).Compared with Ag 3VO 4/TiO 2nanocomposite (Fig.2B),the nanoparticles in Ag 3VO 4/TiO 2/GR nanocomposite possessed bet-ter dispersion degree.The high resolution transmission electron microscopy (HRTEM)image of Ag 3VO 4/TiO 2/GR (the marked loca-tion of Fig.2C with one black circle)was presented in Fig.2D.The fringes of d =0.25nm,d =0.22nm and d =0.23nm observed in Fig.2D matched those of (301)and (400)and (022)crystallo-graphic planes of Ag 3VO 4.The fringes of d =0.35nm and d =0.19nm corresponded to the (101)and (200)crystallographic planes of anatase TiO 2.The intimate contact took place between the coupling Ag 3VO 4and TiO 2in Ag 3VO 4/TiO 2/GR nanocomposite.
3.1.2.Wide spectral response
As is known to all,the wavelength range of light absorption for photocatalyst plays an important role in the photocatalysis,espe-cially for the visible light photocatalytic degradation of organic pollutants.The UV–vis DRS patterns of TiO 2,Ag 3VO 4,TiO 2/GR,Ag 3VO 4/TiO 2and Ag 3VO 4/TiO 2/GR composites were shown in Fig.3.The values of band gap for Ag 3VO 4and TiO 2estimated by the onset point of the absorption curve was 2.2eV and 3.2eV,respec-tively.The result of Ag 3VO 4was in agreement with that reported by Konta et al.[36].Based on the analysis of DRS,there was an
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Fig.2.TEM images of (A)TiO 2/GR,(B)Ag 3VO 4/TiO 2,(C)Ag 3VO 4/TiO 2/GR and (D)HRTEM image of Ag 3VO 4/TiO 2/GR (image D is the ampli?cation of the marked location of image C with one black circle).
400
500
600 700
800
102030405060
708090R %
Wavelen gth / nm
TiO 2 Ag 3VO 4 TiO 2/GR Ag 3VO 4/TiO 2 Ag 3VO 4/TiO 2/GR
Fig.3.UV–vis DRS patterns of the prepared samples.
98J.Wang et al./Applied Catalysis B:Environmental 136–137 (2013) 94–102
V a d s /c m 3g
-1
P/P 0
Fig.4.Nitrogen adsorption–desorption isotherm and pore size distribution plot (inset)of the as-prepared Ag 3VO 4/TiO 2/GR.
obvious enhancement in the visible light absorption of TiO 2/GR powder,compared to bare TiO 2.Moreover,the light absorp-tion range of Ag 3VO 4/TiO 2/GR was further extended with the introduction of Ag 3VO 4and then the Ag 3VO 4/TiO 2/GR composite possessed wide spectral response including UV and visible light wavelength.So,a more ef?cient utilization of the solar spectrum on Ag 3VO 4/TiO 2/GR could be achieved,which contributed to the improvement in its photocatalytic activity and facilitated its use in practical environmental remediation.
3.1.3.BET analysis
The nitrogen adsorption–desorption isotherm and pore size distribution plot (inset)of the as-prepared Ag 3VO 4/TiO 2/GR sample were presented in Fig.4.The BET speci?c surface area of Ag 3VO 4/TiO 2/GR was determined to be 86m 2g ?1.N 2-sorption isotherm of the Ag 3VO 4/TiO 2/GR sample belonged to type-IV isotherm with a hysteresis loop according to BDDT (Brunauer,Deming,Deming and Teller)classi?cation,which was typical characterization of mesoporous materials [45–47].The Barrett–Joyner–Halenda (BJH)pore size distribution of Ag 3VO 4/TiO 2/GR composite was narrow,and the most probable pore diameter was 3.5nm which was in the mesoporous region [45].The above results indicated that Ag 3VO 4/TiO 2/GR composite was a porous material.
3.2.Photocatalytic activity and stability
The photocatalytic activities for liquid-phase degradation of MO over the prepared photocatalysts under visible light and simulated solar light irradiation have been tested at room https://www.doczj.com/doc/3314093155.html,-mercial Degussa P25and nitrogen-doped TiO 2(TiO 2?x N x )were employed as comparison.TiO 2?x N x was obtained by traditional process with calcining TiO 2xerogel at 550?C under dry NH 3?ow for 3h [48].As seen from Fig.5A,after 3h of visible light irradiation (420nm < <800nm),the photocatalytic conversion ratios of MO for TiO 2/GR,TiO 2?x N x ,P25,Ag 3VO 4/TiO 2,Ag 3VO 4,Ag 3VO 4/TiO 2/GR were 6%,11%,13%,38%,66%,81%,respectively.Ag 3VO 4/TiO 2/GR composite performed the optimal visible photocatalytic activity in degradation of MO among them.Ag 3VO 4/TiO 2nanocomposite prepared by wet chemical method exhibited lower photocatalytic activity than Ag 3VO 4due to the low ef?ciency of these heterojunc-tions between Ag 3VO 4and TiO 2resulting in inef?cient electron transfer process of activated Ag 3VO 4to TiO 2.Ag 3VO 4/TiO 2/GR per-formed higher visible photocatalytic activity than Ag 3VO 4/TiO 2,
which demonstrated the introduction of GR contributed to the enhancement of activity.As shown in Fig.S4,Ag 3VO 4/TiO 2/GR still maintained the superiority in activity under simulated solar light irradiation (320nm < <800nm).
Blank experiment of RhB without any photocatalyst,labeled by blank,showed that no activity was observed under simulated solar light irradiation.TiO 2and TiO 2?x N x showed little photocat-alytic activity,far lower than Ag 3VO 4/TiO 2/GR within the same interval.Ag 3VO 4/TiO 2/GR nearly completely degraded 10ppm RhB within 40min under visible light irradiation or within 25min under simulated solar light irradiation.As displayed in Fig.5B,the photocatalytic degradation process of RhB is ?t for pseudo ?rst-order kinetics by linear transform ln(C 0/C t )=kt [49].The apparent rate constant k corresponding to P25,Ag 3VO 4/TiO 2and Ag 3VO 4/TiO 2/GR are 0.017min ?1,0.044min ?1,0.065min ?1under visible light and 0.097min ?1,0.073min ?1,0.111min ?1under simulated solar light irradiation,respectively.Ag 3VO 4/TiO 2/GR composite possessed the optimal photocatalytic activity in degra-dation of RhB among them whether in visible or simulated solar light irradiation.The apparent rate constant k of Ag 3VO 4/TiO 2/GR under simulated solar light was nearly two times higher than that under visible light,which further con?rmed the wide spec-tral response and the effective utilization of solar energy for Ag 3VO 4/TiO 2/GR photocatalyst.
Besides MO and RhB,p-chlorophenol (p-CP)as a kind of dif?-cult degradable colorless organic pollutant was used to evaluate the photocatalytic activity of the prepared Ag 3VO 4/TiO 2/GR photocat-alyst under visible light irradiation.Its degradation can exclude the photosensitized reaction.Ag 3VO 4/TiO 2/GR photocatalyst nearly degraded 10ppm p-CP by 30%after 5h of visible light irradiation,which further indicated that Ag 3VO 4/TiO 2/GR composite possessed high visible photocatalytic activity (Fig.S5).
Moreover,the stability of our Ag 3VO 4/TiO 2/GR nanocomposite was evaluated repeatedly four times in terms of performing the RhB degradation under simulated solar light irradiation (shown in Fig.6A).The photocatalytic ef?ciency displayed slight decrease after the reaction was performed consecutive four times.On the basis of XPS analysis of used sample and fresh sample (Fig.6B),the chemical state of photocatalyst did not change after the pho-tocatalytic reaction.Therefore,it is believed that Ag 3VO 4/TiO 2/GR nanocomposite possessed activity stability which was crucial to assess a photocatalyst and its application.
3.3.Discussion of photocatalytic mechanism
3.3.1.Photoelectrochemical property
Photoelectrochemical measurement was performed to further investigate the enhancement mechanism for photocatalytic activ-ity of Ag 3VO 4/TiO 2/GR composite by introducing GR as the support.The transient photocurrent response has been demonstrated to be a useful technique for investigating the ef?ciency of the separa-tion of photogenerated electron–hole pairs [50].Fig.7represented the photocurrent versus time curves for the samples with several on-off cycles of intermittent visible and simulated solar light irra-diation.For the same sample,its photocurrent under simulated solar light irradiation was higher than that under visible light irra-diation.The Ag 3VO 4/TiO 2/GR composite exhibited a signi?cantly higher photocurrent than Ag 3VO 4/TiO 2composite,and TiO 2/GR possessed the lowest photocurrent among them.The photocurrent of Ag 3VO 4/TiO 2/GR was obviously larger than the addition of the photocurrents of Ag 3VO 4/TiO 2and TiO 2/GR,which further con-?rmed that the interaction existed in Ag 3VO 4/TiO 2/GR composite rather than simple mixture.It’s important to note that the shapes of photocurrent curves of Ag 3VO 4/TiO 2/GR and Ag 3VO 4/TiO 2had a great difference.When Ag 3VO 4/TiO 2electrode was illuminated,its photocurrent curve (Fig.7C and D)initially presented a spike
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(A)C /C o
Time / h
(B)
-l n C /C o
Time / min
Fig.5.(A)Liquid-phase photocatalytic degradation of 10ppm MO under visible light and (B)kinetic linear simulation curves of 10ppm RhB over
the prepared photocatalysts,
TiO 2-x N x and P25(V and S following the sample name in Fig.5B respectively represented the visible light and simulated solar light irradiation).
C /C o
Time / min
(A)36036 436 837 237 638
Ag 3d 3/2
used
fresh
C o u n t s / s
Bindin g Energ y/eV
Ag 3d 5/2
(B)
Fig.6.(A)Photocatalytic degradation stability of RhB over Ag 3VO 4/TiO 2/GR nanocomposite and (b)comparison of Ag 3d XPS spectra between used and fresh sample under
simulated solar light irradiation (320nm < <800nm).
0.0
0.40.81.21.6
2.0
P h o t o c u r r e n t /μA
Time / S
Fig.7.Transient photocurrent responses versus time for (A)Ag 3VO 4/TiO 2/GR,(C)Ag 3VO 4/TiO 2,(E)TiO 2/GR under simulated solar light irradiation and (B)Ag 3VO 4/TiO 2/GR,(D)Ag 3VO 4/TiO 2,(F)TiO 2/GR under visible light irradiation.
and then the spike gradually decays until the photocurrent reached a stable value.The decrease in the photocurrent indicates that recombination is occurring within the Ag 3VO 4/TiO 2electrode [51].Although the photogenerated electrons on the conduction band of Ag 3VO 4can transfer to TiO 2,the electrons left in Ag 3VO 4were easy to recombine with holes [52,53].For Ag 3VO 4/TiO 2/GR electrode,its photocurrent (Fig.7A and B)gradually increased under light illumi-nation.After the illumination was turned off the photocurrent did not suddenly disappear but slowly decreased.After the introduc-tion of GR into Ag 3VO 4/TiO 2,its decay of photocurrent in the initial seconds of illumination was eliminated.The reason was that some photogenerated electrons of Ag 3VO 4which did not directly transfer to TiO 2,transfered to GR and were stored within GR.So the recom-bination of photogenerated electrons and holes was inhibited to some degree.The photocurrent was generated from electrons on the conduction band of TiO 2transferred from GR sheets rather than Ag 3VO 4directly,resulting in the gradual increase in photocurrent.When the light was switched off,the gradual release of electrons from GR sheets with the electron storage effect led to the gradual decrease of photocurrent.The observed enhancement in the pho-tocurrent intensity and the difference in shapes of photocurrent curves between Ag 3VO 4/TiO 2/GR and Ag 3VO 4/TiO 2demonstrated the increase in the ef?ciency of the separation of photogenerated
100J.Wang et al./Applied Catalysis B:Environmental 136–137 (2013) 94–102
3480349
5351
0352
5354
Ag 3VO 4/TiO 2/GR
I n t e n s i t y
Magnetic Field / G
In dark
TiO 2/GR Ag 3VO 4/TiO 2
DMPO-?OH
Fig.8.DMPO spin-trapping ESR spectra on Ag 3VO 4/TiO 2/GR in aqueous dispersion
for DMPO-?OH under simulated solar light irradiation.
electron–hole pairs and further con?rmed the ability of GR to cap-ture and shuttle electrons through the ?–?network [46,50,54].
Electrochemical impedance spectroscopy (EIS)was also used to investigate the effect of GR on the separation ef?ciency of photo-generated charges on Ag 3VO 4/TiO 2/GR,Ag 3VO 4/TiO 2and TiO 2/GR under visible light and simulated solar light irradiation (Fig.S6).The radius of the arc on the EIS Nyquist plot represents the charge transfer step occurring at the surface of the electrode [55].The results of EIS plot demonstrated that the ef?ciency of the separa-tion of photogenerated electron–hole pairs increased in the order of TiO 2/GR 3.3.2.Detection of active species The presence of graphene in the Ag 3VO 4/TiO 2/GR nanocompos-ite can effectively inhibit the electron–hole pair recombination,which may caused more radical species with strong oxidation capa-bility,such as hydroxyl radical (?OH)and superoxide radical (O 2??)species,for the degradation of pollutant.In order to further con?rm that,ESR spin-trapping technique with 5,5-Dimethyl-1-pyrroline-N-oxide (DMPO)was carried out to detect the active species under simulated solar light irradiation (320nm < <800nm).Surpris-ingly,the intensity of Ag 3VO 4/TiO 2/GR for DMPO-?OH is lower than Ag 3VO 4/TiO 2(shown in Fig.8).The reason was discussed in the latter photocatalytic mechanism section.DMPO-O 2??was not detected for Ag 3VO 4/TiO 2/GR system.There may be two rea-sons for the phenomenon.First,electrons can become trapped and reduce dioxygen to superoxide O 2??or to hydrogen per-oxide H 2O 2[1].There is competition between two pathways.Second,O 2??may react with H 2O 2to form ?OH radical [56].So,the amount of O 2??decreased too fast to be detected.The N,N-diethyl-p-phenylenediamine (DPD)method was widely employed for the detection of H 2O 2.This method is based on the horseradish peroxidase (POD)-catalyzed oxidation by H 2O 2of DPD [57].The sequence of reaction leaded to the forma-tion of the radical cation DPD ?+,which formed a fairly stable color,with the absorption maxima at 510nm and one at 551nm.The result was shown in Fig.9.For the water sample,there was no obvious absorption peak observed under the same con-dition.Apparently,the amount of H 2O 2followed the order Ag 3VO 4/TiO 2/GR >Ag 3VO 4>Ag 3VO 4/TiO 2>TiO 2/GR,which was in accord with the order of their photocatalytic activities.The results 40045 050 055 060 0.00 0.050.100.150.20 0.25 0.300.35 A b s Waveleng th / nm Ag 3VO 4/TiO 2/GR Ag 3VO 4Ag 3VO 4/TiO 2TiO 2/GR H 2O Fig.9.Absorption spectra of the DPD/POD reagent after reaction with different samples under 0.5h of simulated solar light irradiation. of H 2O 2detection further demonstrated the probable eventual des-tination of electrons. To further investigate the roles of these active species such as electrons/holes,?OH and O 2??in photocatalystic degradation process,different types of active species scavengers were added in catalyst system.Fig.10showed the photocatalytic activity of Ag 3VO 4/TiO 2/GR nanocomposite toward the degradation of RhB under the different conditions.After 0.1g of ammonium oxalate (AO)as a hole-scavenger was added into the reaction system [58],the decrease in the rate of degradation of RhB over Ag 3VO 4/TiO 2/GR was the most obvious,which meant the photogenerated holes may play an important role in the photocatalytic degradation.The ben-zoquinone (BQ)has the ability to trap O 2??by a simple electron transfer mechanism [59].The addition of BQ (1mg)provoked par-tial inhibition of the RhB degradation.N 2was bubbled through the suspension at the rate of 20mL/min to ensure that the reaction was operated without dissolved O 2as an electron scavenger to produce a variety of active oxygen species.The following decrease of activ-ity further indicated O 2??played a role in the degradation of RhB.After 2mL of tert-butyl alcohol (TBA)as a scavenger for ?OH was added in the system,it did not obviously impact the decomposition rate.So,the degradation of RhB was driven by the contribution of 510152025 0.0 0.2 0.4 0.6 0.8 1.0 C /C o Time / min Fig.10.Photocatalytic degradation of RhB over Ag 3VO 4/TiO 2/GR nanocom-posite under different conditions with exposure to simulated solar light (320nm < <800nm). J.Wang et al./Applied Catalysis B:Environmental136–137 (2013) 94–102 101 Scheme1.Proposed mechanism for photocatalytic degradation of organic pollut-ants(MO,RhB)on Ag3VO4/TiO2/GR nanocomposite(black sheet represented GR in the diagram)under visible light irradiation(solid line)and simulated solar light irradiation(solid line and dashed line). ?OH radicals to a lesser extent.Based on the integrated analysis of these results,we can conclude that the degradation of RhB was driven mainly by the participation of holes and O2??radicals played a secondary role and?OH radicals to a lesser extent partook in that process. 3.3.3.The proposed photocatalytic mechanism The relative positions of energy bands of Ag3VO4and TiO2were known according to the results reported in the literature[53]. Based on the results of photoelectrochemical measurement,ESR spin-trapping technique,DPD method and the addition of active species scavengers,the mechanism for photocatalytic degradation of organic pollutants(MO,RhB)on Ag3VO4/TiO2/GR nanocompos-ite was proposed and represented in Scheme1.For Ag3VO4/TiO2/GR nanocomposite,Ag3VO4and TiO2dispersed on the GR sheet.Some Ag3VO4and TiO2particles contacted intimately and some sepa-rated.For close contacting Ag3VO4and TiO2under simulated solar light irradiation,the excited electrons on conduction band(CB)of Ag3VO4can directly transfer to CB of TiO2,and the excited holes on valence band(VB)of TiO2also can directly transfer to VB of Ag3VO4, which did not happen under visible light irradiation.For separated Ag3VO4and TiO2,the pathways of electron transfer between them changed.When subjected to simulated solar light irradiation,the photogenerated electrons transferred from CB of Ag3VO4to the graphene sheets.The two-dimensional planar conjugation struc-ture in graphene facilitated interfacial charge transfer along the graphene sheets to TiO2and subsequently an effective charge sep-aration was achieved.Then,electrons were trapped by the adsorbed molecular oxygen on the TiO2surface to produce superoxide anion (O2??)radicals or H2O2[1].Electrons left on Ag3VO4also could be trapped to form O2??radicals or H2O2.The production of H2O2in our photocatalystic system was con?rmed by DPD method and the role of O2??was con?rmed by method of active species scavengers. The transfer of holes from VB of TiO2to Ag3VO4was accelerated with the addition of GR,which was demonstrated by the decrease in intensity of?OH for Ag3VO4/TiO2/GR compared with Ag3VO4/TiO2 detected by ESR technique.The photogenerated holes on VB of TiO2can directly oxidate water to generate?OH radical but the holes on Ag3VO4cannot oxidate water although they easily acti-vated organic pollutants,leading to a subsequent decomposition. The holes indeed played an important role in Ag3VO4/TiO2/GR photocatalytic system on the basis of the results of active species scavengers.As a result,the ability of GR to capture and shuttle electrons enhanced the ef?ciency of the separation of photogen-erated electron–hole pairs so that they can be fully involved in the photocatalytic reactions and a highly ef?cient photocatalytic activ-ity was achieved. 4.Conclusions Ag3VO4/TiO2/graphene nanocomposite prepared?rst by a two-step process possessed a wide spectral response and exhibited obviously increased photocatalytic activity in degradation of organic pollutants including methyl orange and Rhodamine B, compared with Ag3VO4/TiO2and TiO2/GR nanocomposites.The enhancement of photocatalytic activity was attributed to three aspects:?rst,light absorption was extended to longer wavelengths to reach wide spectral response;second,graphene as support mate-rial contributed to the uniform dispersion of Ag3VO4and TiO2 nanoparticles on graphene sheets;third,the formation of hetero-juction between Ag3VO4and TiO2and the capacity of storing and shuttling electrons of graphene inhibited the photogenerated car-riers recombination.Based on the results of detection of active species,we can conclude that the degradation of RhB was driven mainly by the participation of holes.O2??radicals and?OH radicals and H2O2to a lesser extent partook in this process.Therefore,the transfer of photogenerated carriers and photocatalytic degradation mechanism on Ag3VO4/TiO2/GR nanocomposite were proposed and discussed. 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[59]R.Palominos,J.Freer,M.A.Mondaca,H.D.Mansilla,Journal of Photochemistry and Photobiology A193(2008)139–145. 石墨烯复合材料的研究及其应用 任成，王小军，李永祥，王建龙，曹端林 摘要：石墨烯因其独特的结构和性能，成为物理化学和材料学界的研究热点。本文综述了石墨烯复合材料的结构和分类，主要包括石墨烯-纳米粒子复合材料、石墨烯-聚合物复合材料和石墨烯-碳基材料复合材料。并简述石墨烯复合材料在催化领域、电化学领域、生物医药领域和含能材料领域的应用。 关键词：石墨烯；复合材料；纳米粒子；含能材料 Research and Application of Graphene composites ABSTRACT: Graphene has recently attracted much interest in physics,chemistry and material field due to its unique structure and properties. This paper reviews the structure and classification of graphene composites, mainly inclouding graphene-nanoparticles composites, graphene-polymer composites and graphene-carbonmaterials composites. And resume the application of graphene composites in the field of catalysis, electrochemistry, biological medicine and energetic materials. Keywords: graphene; composites; nanoparticles; energetic materials 石墨烯自2004年曼彻斯特大学Geim[1-3]等成功制备出以来，因其独特的结构和性能，颇受物理化学和材料学界的重视。石墨烯是一种由碳原子紧密堆积构成的二维晶体，是包括富勒烯、碳纳米管、石墨在内的碳的同素异形体的基本组成单元。石墨烯的制备方法主要有机械剥离法，晶体外延法，化学气相沉积法，插层剥离法以及采用氧化石墨烯的高温脱氧和化学还原法等[4-10]。与碳纳米管类似，石墨烯很难作为单一原料生产某种产品，而主要是利用其突出特性与其它材料体系进行复合．从而获得具有优异性能的新型复合材料。而氧化石墨烯由于其特殊的性质和结构，使其成为制备石墨烯和石墨烯复合材料的理想前驱体。本文综述了石墨烯复合材料的结构、分类及其在催化领域、电化学领域、生物医药领域和含能材料领域的应用。 石墨烯及石墨烯光催化复合材料简介 1.1 前言 碳材料是地球上最普遍也是一类具有无限发展前景的材料，从无定形的碳黑到晶体结构的天然层状石墨；从零维纳米结构的富勒烯到二维结构的石墨烯，近几十年来，碳纳米材料一直备受关注。而三维网状结构的石墨烯自组装水凝胶的发现[1]，不仅极大地充实了碳材料家族，为新材料和凝聚态领域提供了新的增长点，而且由于其所具有的特殊纳米结构和性能，使得石墨烯无论是在理论上还是实验研究方面都已展现出了重大的科学意义和应用价值．从而为碳基材料的研究提供了新的目标和方向。 从石墨发现至今，关于石墨烯的研究已经铺满各种期刊杂志，此外，人们对石墨烯衍生物也进行了深入研究，如氧化石墨烯、石墨烯纳米带、石墨烷、磁性石墨烯衍生物等。其中对氧化石墨烯和石墨烯纳米带的研究更为深入。氧化石墨烯是单一的碳原子层，可以随时在横向尺寸上扩展到数十微米，因此，其结构跨越了一般化学和材料科学的典型尺度。氧化石墨烯可视为一种非传统型态的软性材料，具有聚合物、胶体、薄膜，以及两性分子的特性。由于它在水中具有优越的分散性，长久以来被视为亲水性物质，然而，相关实验结果显示，氧化石墨烯实际上具有两亲性，从石墨烯薄片边缘到中央呈现亲水至疏水的性质分布。因此，氧化石墨烯可如同界面活性剂一般存在界面，并降低界面间的能量。根据不同的碳取材来源和不同的结构，石墨烯纳米带有不同的特性，有些有金属的性质，有的具有半导体性能，从而也使得石墨烯纳米带成为未来半导体候选材料。此外，在挖掘石墨烯潜在的性能和应用方面，石墨烯的复合材料也受到了极大的关注，并且这类复合材料已在生物医学、能量储存、液晶器件、传感材料、电子器件、催化剂等领域显示出了优异的性能和潜在的应用。 总之，不断发现新的性质、衍生物、复合材料以及功能器件，极大地丰富了石墨烯的研究方向、开拓了人们的视野、拓展了石墨烯的应用领域，使得基于石墨烯的材料成为了一个充满魅力与无限可能的研究对象。 石墨烯复合材料 石墨烯是单层碳原子通过sp2杂化形成的蜂窝点阵结构，属于二维原子晶体，此独特的空间结构，给石墨烯带来了优异的电学、力学、热学和比表面积大等性质。但是二维石墨烯由于片层之间具有较强的π-π作用和范德华力，使得石墨烯容易聚集形成石墨，限制了石墨烯在各个领域中的应用。因此，为了防止石墨烯的聚集和拓展石墨烯的应用，科研工作者将石墨烯与高分子或者无机纳米粒子进行复合，从而得到具有优异性能的复合材料。石墨烯的复合材料具有化学稳定性高、比表面积大，易回收等特点，在环境治理方面受到了科学家的青睐。 一、石墨烯复合材料的分类和制备 1、石墨烯-高分子复合材料 石墨烯-高分子复合材料，石墨烯的独特的结构和性能，对于改善高分子的导电性、热性能和吸附能力等方面有非常大的应用价值。制备石墨烯-高分复合材料最直接的方法是将高分子溶液与石墨烯的溶液混合，其中高分子和填充物在溶剂中的溶解能力是保证最佳分散度的重要因素。因此，在溶液混合时，可以将石墨基质表面功能化来提高它在多种溶剂中的溶解度。例如，异氰酸 苯酯修饰的GO在在聚苯乙烯的DMF溶液中表现出了较好的溶解度。 2、石墨烯-无机纳米粒子复合材料 无机纳米粒子存在着易于团簇的问题，并且选择合适的载体也是其广泛应用需要解决的问题。石墨烯具有多种优异的性能，并且具有较大的比表面积，可以成为无机纳米材料的载体。无机纳米粒子可以将易于团簇的石墨烯片层分开，防止团簇，从而两者形成石墨烯-无机纳米粒子新型的复合材料，这些材料广泛的应用于检测、催化和气体存储等方面。目前已报道的有负载的金属纳米粒子Ag、Au、氧化物纳米粒子ZnO和Fe3O4等。 3、其它石墨烯复合材料 石墨烯不仅仅可以和高分子、无机纳米材料复合，还可以同时结合高分子、纳米粒子和碳基材料中的一种或者两种，形成多元的含有石墨烯的复合材料。这类材料具有多功能性，用于超级电容器或者传感器等。 二、石墨烯复合材料在水治理的应用 1、吸附作用 碳材料中活性碳和碳纳米管被广泛的应用于水净化领域，将石墨烯与其它化合物进行复合，这些复合材料在吸附污染物上有非常高的效率，可以应用于染料、多芳香环烃和汽油的吸附。比如利用磁性-壳聚糖-石墨烯的复合材料可以大大提高去除溶液中的亚甲基蓝的效率，吸附能力达到 文章编号:１００１-９７３１(２０１６)０７-０７０３４-０４ 石墨烯基光催化剂在能源转化方面的应用? 董倩,伍水生,马博凯,王亚明 (昆明理工大学化学工程学院,昆明６５０５０４) 摘要:石墨烯半导体复合纳米材料被视为一种最有潜力的光催化剂,由于其独特的物理化学性质在太阳能转化为化学能领域十分引人注目.石墨烯基光催化剂活性的增强机理包括光生电子-空穴对复合的减少,光吸收范围的扩大和光吸收强度的增强,表面活性位点的增加以及光催化剂化学稳定性的改善.综述石墨烯基光催化剂在能源转化如光催化分解水和CO２的光催化还原成碳氢化合物的应用并且简要分析了其活性增强的机理.关键词:石墨烯基纳米材料;光催化;光解水;能源转化 中图分类号: O６１１．４文献标识码:A DOI:１０．３９６９/j．issn．１００１-９７３１．２０１６．０７．００７ ０ 引言 石墨烯,由s p２杂化碳原子组成的单层二维纳米片,是一种零带隙半导体.自从２００４年通过简单的机械剥离得到石墨烯之后[１],发现它具有优异的物理化学性质如高柔性结构[２],大表面积(２６３０m２/g)[３],高导电性和导热性(约５０００W/(m K))[４].由于这些独特的特性,导致了研究者对石墨烯的关注,并进一步探讨它在材料科学领域的潜能.石墨烯以及它的衍生物的合成方法大致包括两类: to p-down 和 bottom-u p . to p-down 的外延生长方法一般包括化学气相沉积法[５-９]和有机合成法[１０-１２],它不仅能够制造大尺寸和高品质的石墨烯同时也可调整其形态与结构[１３-１５]. bottom-u p 生长的石墨烯包括机械剥离石墨[１]二石墨电化学膨胀[１６]以及由石墨烯氧化物(GO)还原的石墨烯,虽然石墨烯来自还原氧化石墨烯不可避免地引入了含氧基团和缺陷,但这是具有大规模二低成本制备石墨烯的简单策略[１７]. 利用石墨烯的导电性能好和高比表面积,将它与半导体复合构成新型复合光催化剂一方面可以提高光生电子迁移率使光生电子-空穴对易于分离,从而加速光催化反应.另一方面大比表面积的石墨烯有助于提高污染物分子在催化剂表面的吸附能力[１８-２０].这里,我们重点评述了最近有关石墨烯光催化剂在能源转化方面的的研究.首先介绍了石墨烯复合材料在能源转化方面如光催化分解水和光催化还原CO２的应用,然后简要说明了石墨烯复合材料光催化活性增强的基本原理.１石墨烯基光催化剂在能源转化方面的应用１．１光催化分解水 吸收太阳能来分解水是生产H２和O２最洁净的的方法之一,太阳能分解水制备H２对开发无碳燃料和可持续能源系统是一种有前途的解决方案.然而这种技术的实际应用受限于无法利用可见光,量子效率低,和/或催化剂的光降解[２１].考虑到石墨烯良好的导电率和高比表面积,石墨烯作为有效的电子受体以提高光生电荷转移以及通过分离氢氧的析出位点来抑制逆向反应从而提高光催化产生H２活性(图１所示). 图１光解水在作为电子受体的石墨烯的不同位点选择性催化示意图 Fi g１Schematic illustration of selective catal y sis of water s p littin g at different sites on g ra p hene used as a conductin g su pp ort 溶胶-凝胶法合成的TiO２-５％(质量分数)g ra p hene 复合材料在紫外照射下H２的析出量(４．５μmol/h)比P２５高出２倍,可能是引入石墨烯降低了光生电子-空穴对的复合[２２-２３].通过水热法制备的P２５-RGO具有更好的性能(P２５/RGO质量比＝１/０．２,H２:７４μmol/h),水热反应导致P２５和石墨烯之间产生强相互作用,显示出比P２５(H２:６．８μmol/h)更高的活性[２４-２５].理论计算揭示了锐钛矿型TiO２的{００１}面为具有最高表面能反应面,催化结果显示紫外照射下石墨烯-暴露{００１}面的改性TiO２纳米片(石墨烯含量 ４３０７ ０２０１６年第７期(４７)卷 ?基金项目:国家自然科学基金资助项目(２１４０１０８８);云南省应用研究基础资助项目(KKSY２０１２０５０２５);昆明理工大学分析测试基金资助项目(２０１５０３５７,２０１５０３２０) 收到初稿日期:２０１５-０５-２６收到修改稿日期:２０１５-０８-０６通讯作者:伍水生,E-mail:wuss２００５＠１２６．com 作者简介:董倩(１９９０－),女,陕西宝鸡人,在读硕士,师承伍水生副教授,从事石墨烯纳米材料研究. 常熟理工学院学报（自然科学）Journal of Changshu Institute Technology （Natural Sciences ）第26卷第10Vol.26No.102012年10月Oct.,2012 收稿日期：2012-09-05 作者简介：季红梅（1982—），女，江苏启东人，讲师，工学硕士，研究方向：无机功能材料．水热合成Fe 2O 3/石墨烯纳米 复合材料及其电化学性能研究 季红梅1，于湧涛2，王露1，王静1，杨刚1 （1.常熟理工学院化学与材料工程学院，江苏常熟215500；2.吉林石化公司研究院，吉林吉林132021） 摘要：利用水热法成功合成了Fe 2O 3/石墨烯（RGO ）锂离子电池负极材料.导电性能良好的石墨烯网络起到连接导电性能极差的Fe 2O 3和集流体的作用.电化学性能测试表明，180℃下得到的 Fe 2O 3/RGO 具有良好的比容量和循环稳定性.在不同倍率充放电过程中，初始放电比容量为1023.6mAh/g （电流密度为40mA/g ），电流密度增加到800mA/g 时，放电比容量维持在406.6 mAh/g ，大于石墨的理论放电比容量~372mAh/g.在其他较高的电流密度下比容量均保持基本不变.该Fe 2O 3/RGO 有望成为高容量、低成本、低毒性的新一代锂离子电池负极材料.关键词：Fe 2O 3；石墨烯；负极材料中图分类号：TM911文献标识码：A 文章编号：1008-2794（2012）10-0055-05 自从P.Poizot [1]等报道过渡金属氧化物可以作为锂离子电池负极材料这一研究后，金属氧化物负极便逐渐引起人们的重视.铁的氧化物具有比容量大、倍率性能好和安全性能高等优点，且原料来源丰富、价格低廉、环境友好，因此是一类很有发展潜力的动力锂离子电池负极材料.Fe 2O 3作为一种常温下最稳定的铁氧化合物，理论容量为1005mAh/g ，远高于石墨类材料的理论比容量，已经成为锂离子电池负极材料的一个研究热点.近年来，石墨烯由于其高的电传导性，大的比表面积，良好的化学稳定性和柔韧性而被尝试用于与活性锂离子电池负极材料复合，提升材料的电化学性能.比如，Cui Y [2]课题组在溶剂热条件下两步法得到Mn 3O 4与石墨烯的复合材料，改善了Mn 3O 4的比容量和循环性能.Co 3O 4，Fe 3O 4等金属氧化物材料与石墨烯复合也有被研究，本课题组在石墨烯和金属氧化物材料复合方面也做了大量的工作[3].本文通过水热法一步合成Fe 2O 3/石墨烯纳米复合材料，并研究了其电化学性能，合成过程中采用三乙烯二胺提供反应的碱性环境，并控制Fe 2O 3的粒子生长.1 实验 1.1试剂和仪器 三乙烯二胺（C 6H 12N 2）；无水三氯化铁（FeCl 3）；石墨；硝酸钠（NaNO 3）；浓硫酸（H 2SO 4）；高锰酸钾（KMnO 4）；双氧水（H 2O 2）和盐酸（HCl ），以上试剂均为分析纯.实验用水为去离子水.日本理学H-600型透射电子显微镜；日本理学D/max2200PC 型X 射线衍射仪；德国Bruker Vector 22红外光谱仪；日本JEOL-2000CX 透射电镜；美国Thermo Scientific Escalab 250Xi 光电子能谱仪；LAND 电池 石墨烯在复合材料中的应用 龚欣 （东南大学机械工程学院南京211189） 摘要：介绍了石墨烯与有机高聚物、无机纳米粒子以及其它碳基材料的复合物，同时展望了这些材料在相关领域中的应用前景． 关键词：石墨烯纳米复合材料 2004年至今, 关于石墨烯的研究成果已在SCI检索期刊上发表了超过2000篇论文, 石墨烯开始超越碳纳米管成为了备受瞩目的国际前沿和热点．基于石墨烯的纳米复合材料在能量储存、液晶器件、电子器件、生物材料、传感材料和催化剂载体等领域展现出许多优良性能，具有广阔的应用前景．目前研究的石墨烯复合材料主要有石墨烯/聚合物复合材料和石墨烯/无机物复合材料两类，其制备方法主要有共混法、溶胶-凝胶法、插层法和原位聚合法.本文将对石墨烯的纳米复合材料及其性能等方面进行简要的综述． 一、基于石墨烯的复合物 利用石墨烯优良的特性与其它材料复合可赋予材料优异的性质．如利用石墨烯较强的机械性能，将其添加到高分子中，可以提高高分子材料的机械性能和导电性能；以石墨烯为载体负载纳米粒子，可以提高这些粒子在催化、传感器、超级电容器等领域中的应用． 1.1 石墨烯与高聚物的复合物 功能化后的石墨烯具有很好的溶液稳定性，适用于制备高性能聚合物复合材料．根据实验研究，如用异氰酸酯改性后的氧化石墨烯分散到聚苯乙烯中，还原处理后就可以得到石墨烯-聚苯乙烯高分子复合物．该复合物具有很好的导电性，添加体积分数为1%的石墨烯时，常温下该复合物的导电率可达0.1S/M，可在导电材料方面得到的应用． 添加石墨烯还可显著影响高聚物的其它性能，如玻璃化转变温度(Tg)、力学和电学性能等．例如在聚丙稀腈中添加质量分数约1%的功能化石墨烯，可使其Tg 提高40℃．在聚甲基丙烯酸甲酯（PMMA）中仅添加质量分数0.05%的石墨烯就可以将其Tg提高近30℃．添加石墨烯的PMMA比添加膨胀石墨和碳纳米管的PMMA具有更高的强度、模量以及导电率．在聚乙烯醇（PVA）和PMMA中添加质量分数0.6% 的功能化石墨烯后，其弹性模量和硬度有明显的增加．在聚苯胺中添加适量的氧化石墨烯所获得的聚苯胺-氧化石墨烯复合物的电容量（531F/g）比聚苯胺本身的电容量（约为216F/g）大1倍多，且具有较大的拉伸强度（12.6MPa）．这些性能为石墨烯-聚苯胺复合物在超级电容器方面的应用创造了条件． 石墨烯在高聚物中还可形成一定的有序结构．通过还原分散在Nafition膜中 高分子／石墨烯纳米复合材料研究进展 高秋菊１，夏绍灵１，２＊ ，邹文俊１，彭 进１，曹少魁２ （１．河南工业大学材料科学与工程学院，郑州 ４５０００１；２．郑州大学材料科学与工程学院，郑州 ４５００５２ ）收稿：２０１２－０１－０９；修回：２０１２－０４－ ２４；基金项目：郑州科技攻关项目（０９１０ＳＧＹＧ２３２５８－ １）；作者简介：高秋菊（１９８４—），女，硕士研究生，主要从事高分子复合材料的研究。Ｅ－ｍａｉｌ：ｇａｏｑｉｕｊ ｕ２００８＠ｙａｈｏｏ．ｃｏｍ．ｃｎ；＊通讯联系人，Ｔｅｌ：０３７１－６７７５８７２２；Ｅ－ｍａｉｌ：ｓｈａｏｌｉｎｇ ＿ｘｉａ＠ｈａｕｔ．ｅｄｕ．ｃｎ． 摘要： 石墨烯以其优异的力学、光学、电学和热学性能，得到日益广泛的关注和研究。本文介绍了石墨烯的结构、性能和特点，并对石墨烯的改性方法进行了概括。本文着重综述了高分子／石墨烯纳米复合材料的研究现状和进展，并介绍了高分子／石墨烯纳米复合材料的三种制备方法，即原位插层聚合法、溶液插层法和熔融插层法。此外，还对高分子／石墨烯纳米复合材料的应用前景进行了展望，并对石墨烯复合材料研究存在的问题和未来的研究方向进行了讨论。 关键词：石墨烯；高分子；纳米复合材料；研究进展 引言 石墨烯是以ｓｐ２ 杂化连接的碳原子层构成的二维材料， 其厚度仅为一个碳原子层的厚度。这种“只有一层碳原子厚的碳薄片”，被公认为目前世界上已知的最薄、最坚硬、最有韧性的新型材料。石墨烯具 有超高的强度，碳原子间的强大作用力使其成为目前已知力学强度最高的材料。石墨烯比钻石还坚硬， 强度比世界上最好的钢铁还高１００倍［１］ 。石墨烯还具有特殊的电光热特性， 包括室温下高速的电子迁移率、 半整数量子霍尔效应、自旋轨道交互作用、高理论比表面积、高热导率和高模量、高强度，被认为在单分子探测器、集成电路、场效应晶体管等量子器件、功能性复合材料、储能材料、催化剂载体等方面有广泛 的应用前景［ ２］ 。石墨烯是一种疏松物质，在高分子基体中易团聚，而且石墨烯本身不亲油、不亲水，在一定程度上也限制了石墨烯与高分子化合物的复合，尤其是纳米复合。因而，很多学者对石墨烯的改性进行了大量的研究，以提高石墨烯和高分子基体的亲和性，从而得到优异的复合效应。 １ 石墨烯的改性方法 １．１ 化学改性石墨烯 该方法基于改性Ｈｕｍｍｅｒｓ法［３］ 。首先，由天然石墨制得石墨氧化物， 再通过几种化学方法获得可溶性石墨烯。其化学方法包括：氧化石墨在稳定介质中的还原［４］、通过羧基酰胺化的共价改性［５］ 、还原氧化石墨烯的非共价功能化［ ６］、环氧基的亲核取代［７］、重氮基盐的耦合［８］ 等。此外，还出现了对石墨烯的氨基化［９］、酯化［１０］、异氰酸酯［１１］ 改性等。用化学功能化的方法对石墨烯进行改性，不仅可以提高其溶解性 和加工性能，还可以增强有机高分子间的相互作用。１．２ 电化学改性石墨烯 利用离子液体对石墨烯进行电化学改性已见报道［１２］ 。用电化学的方法，使石墨变成用化学改性石 墨烯的胶体悬浮体。石墨棒作为阴极，浸于水和咪唑离子液的相分离混合物中。以１０～２０Ｖ的恒定电 · ７８· 第９期 高 分 子 通 报 河北工业大学 材料科学与工程学院 石墨烯及其纳米复合材料发展概况 专业金属材料 班级材料116 学号111899 姓名李浩槊 2015年01月05日 摘要 自从2004年，英国曼彻斯特大学物理学家安德烈·海姆和康斯坦丁·诺沃肖洛夫，成功地在实验中从石墨中分离出石墨烯，石墨烯因其优异的力学、电学和热学性能已经成为备受瞩目的研究热点。 石墨烯的碳原子排列与石墨的单原子层雷同，是碳原子以sp2混成轨域呈蜂巢晶格(honeycomb crystal lattice)排列构成的单层二维晶体。石墨烯可想像为由碳原子和其共价键所形成的原子尺寸网。石墨烯是世上最薄也是最坚硬的纳米材料，它几乎是完全透明的，只吸收2.3%的光；导热系数高达5300 W/（m·K），高于碳纳米管和金刚石，常温下其电子迁移率超过15000 cm2 /（V·s），又比纳米碳管或硅晶体高，而电阻率只约10-6Ω·cm，比铜或银更低，为世上电阻率最小的材料。因为它的电阻率极低，电子跑的速度极快，因此被期待可用来发展出更薄、导电速度更快的新一代电子元件或晶体管。由于石墨烯实质上是一种透明、良好的导体，也适合用来制造透明触控屏幕、光板，甚至是太阳能电池。 石墨烯的结构非常稳定，石墨烯内部的碳原子之间的连接很柔韧，当施加外力于石墨烯时，碳原子面会弯曲变形，使得碳原子不必重新排列来适应外力，从而保持结构稳定。这种稳定的晶格结构使石墨烯具有优秀的导热性。 但是，因为石墨烯片层之间存在很强的范德华力，导致其很容易堆积团聚，在一般溶剂中的分散性很差，所以其应用领域受到了限制。本文通过收集、查阅多篇有关石墨烯研究的论文，分析、整理了石墨烯及其纳米复合材料的制备技术发展及其应用的相关知识、理论。 关键词：石墨烯纳米材料制备复合材料 石墨烯基复合材料的制备及吸波性能研究 进展 摘要随着吉赫兹（GHz）频率范围的电磁波在无线通信领域的广泛应用，诸如电磁干扰、信息泄露等问题亟待解决。此外，军事领域中的电磁隐身技术与导弹的微波制导需要，使得电磁波吸收材料受到持续而广泛的关注。因此，迫切需要发展一种厚度薄、频带宽、强吸收的吸波材料。 石墨烯作为世界上最薄硬度最强的纳米材料，优点很多，例如石墨烯制成的片状材料中，厚度最薄，比表面积较大，具有超过金刚石的强度等，这些优点满足吸波材料的需求。石墨烯基复合材料在满足吸波材料基本要求的基础上又提升了材料吸收波的能力。 本文简单地介绍了吸波材料及石墨烯，综述概况了石墨烯基复合材料的研究现状，包括石墨烯复合材料制备方法、微观形貌以及复合材料的吸波性能，提出了石墨烯基复合吸波材料未来的发展方向。 关键词石墨烯基；吸波材料；纳米材料 Progress in Preparation and absorbing properties of graphene-based composites Abstract With the gigahertz (GHz) frequency range of the electromagnetic waves are widely used in wireless communications, such as electromagnetic interference, information leaks and other problems to be solved. In addition, military stealth technology in the field of electromagnetic and microwave guided missiles require such electromagnetic wave absorbing material is subjected to a sustained and widespread concern. Therefore, an urgent need to develop a thin, wide frequency band, a strong absorption of absorbing materials. Graphene as the strongest of the world's thinnest hardness nanomaterials, has many advantages, such as a sheet material made of graphene, the thinnest, large specific surface area, with more than a diamond of strength, these benefits meet absorbers It needs. Graphene-based composites on the basis of absorbing materials to meet the basic requirements but also enhance the ability of the material to absorb waves. This article briefly describes the absorbing material and graphene, graphene reviewed before the status quo based composite materials research, including graphene composite material preparation, morphology and absorbing properties of composites made of graphene-based composite 第３期２０１７年６月 矿产保护与利用 CONSERVATION AND UTILIZATION OF MINERAL RESOURCES №．３ Ｊｕｎ．２０１７ 矿物材料 石墨烯的制备及其在光催化材料中的应用倡 李珍1，2，杨剑波1，2，刘学琴1，2，沈毅1，2，李云国3，张寄丹3 （１．纳米矿物材料及应用教育部工程研究中心，湖北武汉４３００７４；２．中国地质大学材料与化学学院，湖北武汉４３００７４；３．黑龙江省第六地质勘察院，黑龙江佳木斯１５４０００） 摘 要：以黑龙江鸡西柳毛鳞片石墨为原料制备石墨烯，重点探讨了氧化剂配比、氧化时间对氧化石墨结构 的影响，表征了氧化石墨、氧化石墨烯与石墨烯的晶体结构与形貌特征。并将石墨烯与氧化锌纳米棒阵列 （ＲＧＯ／ＺＮＲｓ）复合，研究了石墨烯浓度对石墨烯／氧化锌纳米棒阵列复合材料光催化降解性能的影响，分析 了复合材料的光降解机制。结果表明：鸡西柳毛天然鳞片石墨成功制备成单层或少层还原氧化石墨烯片，厚 度为１．１～１．３ｎｍ。石墨烯的引入有效增强了ＲＧＯ／ＺＮＲｓ复合材料光催化降解性能。当石墨烯浓度为２ ｍｇ／ｍＬ时，ＲＧＯ／ＺＮＲｓ复合材料中石墨烯的含量达到最优值，光催化性能最佳。 关键词：石墨；石墨烯；ＲＧＯ／ＺＮＲｓ复合材料；光催化降解 中图分类号：ＴＢ３８３ 文献标识码：Ｂ 文章编号：１００１－００７６（２０１７）０３－００８４－０６ ＤＯＩ：１０．１３７７９／ｊ．ｃｎｋｉ．ｉｓｓｎ１００１－００７６．２０１７．０３．０１６ Preparation of Graphene and Its Application in Photocatalytic Materials LI Zhen1，2，YANG Jianbo1，2，LIU Xueqin1，2，SHEN Yi1，2，LI Yunguo3，ZHANG Jidan3（1．Engineering Research Center of Nano－geomaterials of Ministry of Educationm，Wuhan430074，Chi－na；2．Faculty of Materials Science and Chemistry，China University of Geosciences，Wuhan430074，Chi－na；3．The Six Institute of Geology Exploration of Heilongjiang Province，Jamusi154000，China）Abstract：ＧｒａｐｈｅｎｅｈａｄｂｅｅｎｆａｂｒｉｃａｔｅｄｕｓｉｎｇＨｅｉｌｏｎｇｊｉａｎｇＪｉｘｉＬｉｕｍａｏｆｌａｋｅｇｒａｐｈｉｔｅａｓｒａｗｍａｔｅ－ ｒｉａｌｓ．Ｔｈｅｅｆｆｅｃｔｓｏｆｏｘｉｄａｎｔｒａｔｉｏ，ｏｘｉｄａｔｉｏｎｔｉｍｅｏｎｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｓａｎｄｍｏｒｐｈｏｌｏｇｙｆｅａｔｕｒｅｓｏｆ ｇｒａｐｈｉｔｅｏｘｉｄｅ，ｇｒａｐｈｅｎｅｏｘｉｄｅａｎｄｇｒａｐｈｅｎｅｈａｄｂｅｅｎｃｈａｒａｃｔｅｒｉｚｅｄａｎｄａｎａｌｙｚｅｄ，ｒｅｓｐｅｃｔｉｖｅｌｙ． ＴｈｅｅｆｆｅｃｔｏｆＫＭｎＯ４ｄｏｓａｇｅｏｎｔｈｅｑｕａｌｉｔｙｏｆｇｒａｐｈｉｔｅｗａｓｄｉｓｃｕｓｓｅｄｉｎｄｅｔａｉｌ．Ｔｈｅｎｗｅｃｏｍｂｉｎｅｄ ＺｎＯｎａｎｏｒｏｄａｒｒａｙｓ（ＲＧＯ／ＺＮＲｓ）ｗｉｔｈｔｈｅｇｒａｐｈｅｎｅ，ａｎｄｔｈｅｅｆｆｅｃｔｓｏｆｇｒａｐｈｅｎｅｃｏｎｃｅｎｔｒａｔｉｏｎｏｎ ｔｈｅｐｈｏｔｏｃａｔａｌｙｔｉｃｄｅｇｒａｄａｔｉｏｎｐｒｏｐｅｒｔｉｅｓｏｆＲＧＯ／ＺＮＲｓｈａｄｂｅｅｎｓｔｕｄｉｅｄ．Ａｄｄｉｔｉｏｎａｌｌｙ，ｔｈｅｐｈｏｔｏ－ ｄｅｇｒａｄａｔｉｏｎｍｅｃｈａｎｉｓｍｏｆｔｈｅｃｏｍｐｏｓｉｔｅｓｈａｄｂｅｅｎｉｎｖｅｓｔｉｇａｔｅｄ．ｉｔｔｕｒｎｓｏｕｔｔｈａｔｔｈｅｆａｂｒｉｃａｔｅｄｇｒａ－ ｐｈｅｎｅｅｘｈｉｂｉｔｅｄｏｎｅｏｒｓｅｖｅｒａｌｌａｙｅｒｓｆｏｒｔｈｅｌｅｓｓｔｈｉｃｋｎｅｓｓ（１．１－１．３ｎｍ）．ＴｈｅＲＧＯ／ＺＮＲｓｄｉｓ－ ｐｌａｙｅｄａｎｅｎｈａｎｃｅｄｐｈｏｔｏｃａｔａｌｙｔｉｃｄｅｇｒａｄａｔｉｏｎｐｒｏｐｅｒｔｙｄｕｅｔｏｔｈｅｉｎｔｒｏｄｕｃｉｎｇｏｆｇｒａｐｈｅｎｅ．Ｆｉｎａｌ－ ｌｙ，ｗｈｅｎｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎｏｆｇｒａｐｈｅｎｅｉｓ２ｍｇ／ｍＬ，ｔｈｅｃｏｍｐｏｓｉｔｅｓｇａｉｎｔｈｅｏｐｔｉｍａｌｐｈｏｔｏｃａｔａｌｙｔｉｃ ｐｅｒｆｏｒｍａｎｃｅ． Key words：ｇｒａｐｈｉｔｅ；ｇｒａｐｈｅｎｅ；ＲＧＯ／ＺＮＲｓｃｏｍｐｏｓｉｔｅ；ｐｈｏｔｏｃａｔａｌｙｔｉｃｄｅｇｒａｄａｔｉｏｎ 石墨在电气工业、化学工业、冶金铸造、核工业、航天工业等诸多领域中都有广泛的应用。随着石墨 倡收稿日期：２０１７－０４－１２ 基金项目：黑龙江国土资源厅项目（２０１６０２） 作者简介：李珍（１９６３－），女，山西临汾人，博士，教授，主要从事矿物材料功能化研究。 万方数据 Material Sciences 材料科学, 2019, 9(8), 803-812 Published Online August 2019 in Hans. https://www.doczj.com/doc/3314093155.html,/journal/ms https://https://www.doczj.com/doc/3314093155.html,/10.12677/ms.2019.98100 Research Progress on Graphene Reinforced Aluminum-Based Composites Jiangyu Li1, Shourong Zhao2, Wei Zhang1,2, Yunlai Deng2, Keda Jiang2 1Guangxi Liuzhou Yinhai Aluminum Co., Ltd., Liuzhou Guangxi 2Light Alloy Research Institute, Central South University, Changsha Hunan Received: July 29th, 2019; accepted: August 13th, 2019; published: August 20th, 2019 Abstract Graphene possesses excellent mechanical properties, high thermal conductivity and low density. It is recognized as an ideal reinforcing material for metal matrix composites (MMC). In this paper, the preparation methods of graphene reinforced aluminum matrix composites are reviewed, the research status of powder metallurgy, stir casting process and other methods is summarized. Casting process effects of different preparation methods on the microstructure and properties of graphene reinforced aluminum matrix composites were discussed. Its application prospect is also predicted at last. Keywords Grapheme, Aluminum-Based Composites, Manufacturing Methods, Properties 石墨烯增强铝基复合材料的研究进展 李江宇1，赵寿荣2，张伟1,2，邓运来2，姜科达2 1广西柳州银海铝业股份有限公司，广西柳州 2中南大学轻合金研究院，湖南长沙 收稿日期：2019年7月29日；录用日期：2019年8月13日；发布日期：2019年8月20日 摘要 石墨烯具有优异的力学性能、高导热系数和低密度，被公认为金属基复合材料(MMC)的理想增强材料。 本文综述了石墨烯增强铝基复合材料的制备方法，归纳了粉末冶金法、搅拌鋳造法及其他多种方法的研 石墨烯聚合物纳米复合材料的前沿与趋势 聚合物与其他塑料结合形成混纺纤维，与滑石粉及云母混合形成填充系统，和与其他非均质加固物进行模型挤压生产复合材料和杂化材料。这种简单的“混合搭配”方法使得塑料工程师们能够利用聚合物团生产一系列能够控制极端条件的有用的材料。在这种方法中最后加入的事石墨烯------人们早就了解到它的存在但是知道2004年才被制备与鉴定出的碳单原子层。英国曼彻斯特大学的Andre K.Geim和Konstantin S.Novoselov因为分离出碳单原子层而被授予诺贝尔物理学奖。他们的成就导致了聚合物纳米材料的蓝图发生了变化。人们已经长期熟知碳基材料，像金刚石，六方碳和石墨烯。但是聚合物纳米材料研究团体重新燃起的热情主要由于石墨烯可与塑料结合的特性以及它来自于廉价的先驱体。石墨烯的性价比优势在纳米复合材料、镀膜加工、传感器和存储装置的应用上正挑战着碳纳米管。接着，这些只能被想象出来的应用将会出现。事实上，Andre Geim说过“石墨烯对于它的名字来说就是一种拥有最佳性能的非凡的物质。”这能够在目前大量发表的文献中可以看出。石墨烯为什么能够这样引起人们的兴趣呢？本篇综述尝试去处理在石墨烯纳米复合材料新兴潮流中所产生的这类问题。这个工作的范围被石墨烯聚合物纳米复合材料（GPNC）研究员提出期望的发展潜力进行了拓展。 神奇的石墨烯 石墨烯被频繁引用的性能是它的电子传输能力。这意味着一个电子可以在其中不被散射或无障碍地通行。石墨烯的电子迁移率可达到20000cm2/Vs，比硅晶体管高一个数量级。一片最近的综述表明，以改良样品制备的石墨烯，电子迁移率甚至可以超过25000cm2/Vs。石墨烯是否缺少禁带以及大量合成纯石墨烯是否可行只有将来的研究可以解释。目前，非凡的电子传导性能使得石墨烯居于各类物质之首。所以，利用石墨烯代替硅作为基质的可能性将指日可待。虽然石墨烯的电子传导能力要比铜高得多，但是其密度只有铜的1/5。文献中大量记载了石墨烯的电子传导性能极其影响方面的细节。 由于它固有的特性人们开始对它在纳米复合材料的应用产生了兴趣。据预测，一个单层无缺陷的石墨烯薄膜的抗拉强度要比其他任何物质都要大。事实上，James Hone’s小组已经用原子力显微镜研究了独立的单层石墨烯薄膜的断裂强度。他们测得的平均断裂力为1700nN。他们还发现石墨烯这种物质可以抵挡超高的应力（约25%）。这些测量值使得这个团队计算出无缺陷石墨烯薄片的内在强度为45Nm-1。这儿的内在强度被规定为无缺陷的纯物质在断裂之前所能承受的最大应力。石墨烯如此卓越的是由于它相当于1.0Tpa的杨氏模量。在其他的特性中Paul McEuen和同事们只有一个原子厚度的石墨烯薄膜即可隔绝气体，包括氦气。即石墨烯在实际应用中可作为密闭的微室。石墨烯所表现出的热传导性能要比铜高出很多倍。这就意味着石墨烯能够很容易地进行散热。最近对大块石墨烯薄膜的研究表明其热传导系数是600W/(m.K)。石墨烯另外的一个特性是其具有高的比表面积，计算值为2630m2g-1，而碳纳米管仅为1315m2g-1，这使得石墨烯在储能装置应用上成为一个候选材料。Rod Ruoff’s小组通过改性的石墨烯演示了其具有的超高电容性能。对石墨烯的新奇属性的详细描述随处可见石墨烯与碳纳米管相比有一个截然相反的属性是其不含杂质（不含金属），这对构建可靠的传感器和储能装置来说是一个重要的优势。，更进一步，由于它形状与结构，石墨烯或许有更低的毒性，这也成为目前研究的主题。 独立的纳米材料的这些性质使得物理学家，化学家，和材料学家，不论作为理论学家还是实验学家，都为石墨烯的潜力而感到振奋。然而，最重要的问题是去区分炒作还是现实。 摘要 石墨烯的制备、表征及石墨烯/氧化锌光催化剂的制备与性能研究 石墨烯（Graphene，GR）自从2004年被发现以来，因其理想的二维晶体结构和独特的物理性能而成为研究的热点。目前，石墨烯的制备方法主要有：微机械剥离法、化学气相沉积法、外延生长法、氧化石墨烯（Graphene Oxide，GO）溶液还原法。与其它方法相比，氧化石墨烯溶液还原法具有高产量、低成本和可规模化制备等特点，有望成为规模化制备石墨烯的有效途径之一。然而在还原过程中常采用的还原剂肼和水合肼具有易爆炸性和强毒性，易对环境造成危害。因此，需要发现一种环境友好、温和且有效的方法来实现化学还原氧化石墨烯（Chemically Reduced Graphene Oxide，CRGO）的批量制备。 氧化锌（ZnO）因其无毒、成本低等优点被广泛应用于光催化的研究。氧化锌光催化剂光生电子-空穴对的快速复合是氧化锌光催化性能的主要限制因素之一，而石墨烯归因于其良好的电子传输性能和巨大的比表面积，使其成为氧化锌复合改性的理想材料。本论文的研究内容及结果如下： （1）通过简化的Hummers 法，改进的Hummers 法，加压氧化法三种不同方法制备出了氧化石墨烯。利用X射线衍射（XRD）、X射线光电子能谱（XPS）、扫描电镜(SEM) 、透射电镜(TEM)、红外光谱(FT-IR)对其化学组成和形貌进行了表征和分析。结果表明改进的Hummers 方法制备出的氧化石墨烯的具有较高的氧化程度。 （2）在水溶液中，采用具有较强还原能力和环境友好的还原剂腐植酸钠(Sodium Humate, SH)将氧化石墨烯的含氧基团成功移除，制备出稳定均匀的化学还原氧化石墨烯悬浮溶液，碳氧原子比达到3.78。这种制备方法不仅避免了有毒有害的还原剂以及表面活性剂等的添加和使用，也为化学还原氧化石墨烯的批量制备提供了一种简单且环境友好的方法。 （3）通过水热制备出石墨烯/氮掺杂氧化锌复合光催化材料，最佳的制备条件是氮掺杂量为0.4 g，氧化石墨烯和氮掺杂氧化锌的质量比为5%，水热温度为120 °C。在此条件下制备出的石墨烯/氮掺杂氧化锌复合光催化材料经过90 min 的光催化反应，亚甲基蓝的降解效率能达到95%。 石墨烯复合材料的制备及其性能研究进展 论文 题目: 石墨烯复合材料的制备 及其性能研究进展学生姓名: 学号： 院（系）：化工与制药工程系专业班级： 指导教师： 职称： 201 年月 石墨烯复合材料的制备及其性能研究进展 摘要: 石墨烯以其优异的性能和独特的二维结构成为材料领域研究热点。本文综述了石墨烯的制备方法并分析比较了各种方法的优缺点, 简单介绍了石墨烯的力学、光学、电学及热学性能。基于石墨烯的复合材料是石墨烯应用领域中的重要研究方向, 本文详细介绍了石墨烯聚合物复合材料和石墨烯基无机纳米复合材料的制备及应用，以及石墨烯复合材料的展望。 关键词:石墨烯;制备;性能;复合材料 Research Progress on Preparation and properties of graphene composite materials Abstract: Graphene has become a hot research field of material for its excellent performance and unique two-dimensional structure. This paper summarizes the method for preparing graphene and compared the advantages and disadvantages of various methods,introduces the mechanics,graphene optical,electrical and thermal properties. Composite materials based on graphene is an important research direction in the field of application of graphene,this paper introduces the preparation and application of graphene polymer composites and graphene based inorganic nano composite material,and the prospect of graphene composite materials. Key words:graphene;preparation;properties;composite materials石墨烯复合材料的研究及其应用
石墨烯及石墨烯光催化复合材料简介
石墨烯复合材料
石墨烯基光催化剂在能源转化方面的应用-
水热合成Fe2O3石墨烯纳米复合材料及其电化学性能研究
石墨烯在复合材料中的应用
高分子_石墨烯纳米复合材料研究进展
石墨烯及其纳米复合材料发展.
石墨烯基复合材料的制备及吸波性能研究进展
石墨烯的制备及其在光催化材料中的应用
石墨烯增强铝基复合材料的研究进展
高分子石墨烯纳米复合材料的前沿与趋势
石墨烯的制备、表征及石墨烯氧化锌光催化剂的制备与性能研究
石墨烯复合材料的制备及其性能研究进展
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