The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial ...The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.展开更多
A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite(glutathione-GO/ZnO)as electrode material for the high-performance piroxicam sensor.The prepared glutathi...A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite(glutathione-GO/ZnO)as electrode material for the high-performance piroxicam sensor.The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam(oxidation potential is 0.52 V).Under controlled experimental parameters,the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 μM.The detection limit and sensitivity were calculated as 1.8 μM and 0.2 μA/μM·cm^(2),respectively.Moreover,it offered excellent selectivity,reproducibility,and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration.Finally,the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.展开更多
Graphene-ZnO nanocomposites were synthesized successfully through a one-step solvothermal approach. The mor-phology, structure, and composition of the prepared nanocomposites were investigated by scanning electron mic...Graphene-ZnO nanocomposites were synthesized successfully through a one-step solvothermal approach. The mor-phology, structure, and composition of the prepared nanocomposites were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), laser micro Raman spectroscopy, and Fourier transform infra-red spec-troscopy (FT-IR). The outcomes confirmed that this approach is comparatively steady, practicable, and operable compared with other reported methods. The electrochemical performance of the graphene-ZnO electrodes was analyzed through cyclic voltammetry, altering-current (AC) impedance, and chronopotentiometry tests. The graphene-ZnO electrodes exhib-ited an improved electrode performance with higher specific capacitance (115 F·g^-1 ), higher electrochemical stability, and higher energy density than the graphene electrodes and most reported graphene-ZnO electrodes. Graphene-ZnO nanocom-posites have a steady reversible charge/discharge behavior, which makes them promising candidates for electrochemical capacitors (ECs).展开更多
In this research study, we have synthesized the bio-capped ZnO/g-C_(3)N_(4) nanocomposites by employing lemon juice(Citrus limon) as a stabilizer and mediator. Fruitfully, lemon juice which contains various acidic fun...In this research study, we have synthesized the bio-capped ZnO/g-C_(3)N_(4) nanocomposites by employing lemon juice(Citrus limon) as a stabilizer and mediator. Fruitfully, lemon juice which contains various acidic functional groups and citric acid has the capability to block the surface of g-C_(3)N_(4) from chemical reactivity and activated the surface of g-C_(3)N_(4) for various reactions. Consequently, the agglomeration behavior and controlled shape of g-C_(3)N_(4) has also been achieved. Our experimental results i.e. XRD,TEM, HRTEM, PL, FS, XPS, and PEC have confirmed that the lemon juice mediated and green g-C_(3)N_(4)(L-CN) have good performances and remarkable visible light photocatalytic activities as compared to the chemically synthesized g-C_(3)N_(4)(CN). Furthermore, the small surface area and low charge separation of g-C_(3)N_(4) is upgraded by coupling with Zn O nanoparticles. It is proved that the coupling of Zn O worked as a facilitator and photoelectron modulator to enhance the charge separation of g-C_(3)N_(4). Compared to pristine lemon-mediated green g-C_(3)N_(4)(L-CN), the most active sample 5Zn O/L-CN showed ~ 5-fold improvement in activities for ciprofloxacin(CIP) and methylene blue(MB) degradation. More specifically,the mineralization process and degradation pathways, and the mineralization process of ciprofloxacin(CIP) and methylene blue(MB) are suggested. Finally, our present novel research work will provide new access to synthesize the eco-friendly and bio-caped green g-C_(3)N_(4)nanomaterials and their employment for pollutants degradation and environmental purification.展开更多
Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphe...Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.展开更多
Ag/TiO2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of Rh B under visible light irradiation. During the solvothermal process, re...Ag/TiO2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of Rh B under visible light irradiation. During the solvothermal process, reduction of graphene oxide and loading of Ag/TiO2nanoparticles on graphene sheets were achieved. Investigation of chemical state of products showed that covering of Ag/TiO2surface with higher weight ratio of graphene resulting in that Ag metals in Ag/TiO2were oxidized to Ag2 O in nanocomposite structure after solvothermal process. Degree of photocatalytic activity enhancement strongly depends on the coverage of Ag/TiO2surface by porous graphene. The sample of 1 wt% porous graphene hybridized Ag/TiO2showed the highest photocatalytic activity, which is related to high migration efficiency of photoinduced of electrons and reduction of electron–hole recombination rate due to high electrical conductivity of graphene. Expanding of absorption to visible light region was ascribed to surface plasmon resonance effect of Ag metals and presence of graphene. Investigation of photocatalytic performance of formic acid as a dye-less organic pollutant showed that dye sensitization effect of Rh B molecules during evaluation of photocatalytic performance was negligible.展开更多
The cobalt sulfide/graphene oxide(CoS/GO) nanocomposite was synthesized by a simple hydrothermal reaction.The products as-synthesized were characterized by XRD,SEM,TEM,BET-BJH and TG.The electrochemical property and...The cobalt sulfide/graphene oxide(CoS/GO) nanocomposite was synthesized by a simple hydrothermal reaction.The products as-synthesized were characterized by XRD,SEM,TEM,BET-BJH and TG.The electrochemical property and impedance of the CoS/GO nanocomposite were studied by cyclic voltammetry and EIS analysis,respectively.The results show that the presence of the GO enhances the electrode conductivity,and then improves the capacitance property of the CoS/GO nanocomposite.The galvanostatic charge/discharge measurement results show that the CoS/GO nanocomposite has a high specific capacitance(550Fg^-1) and long cycle life(over 1 000 cycles).展开更多
An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the mag...An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.展开更多
Graphene has attracted considerable interest over recent years due to its intrinsic mechanical, thermal and electrical properties. Incorporation of small quantity of graphene fillers into polymer can create novel nano...Graphene has attracted considerable interest over recent years due to its intrinsic mechanical, thermal and electrical properties. Incorporation of small quantity of graphene fillers into polymer can create novel nanocomposites with im- proved structural and functional properties. This review introduced the recent progress in fabrication, properties and potential applications of graphene-polymer composites. Recent research clearly confirmed that graphene-polymer na-nocomposites are promising materials with applications ranging from transportation, biomedical systems, sensors, elec-trodes for solar cells and electromagnetic interference. In addition to graphene-polymer nanocomposites, this article also introduced the synergistic effects of hybrid graphene-carbon nanotubes (CNTs) on the properties of composites. Finally, some technical problems associated with the development of these nanocomposites are discussed.展开更多
We successfully constructed TiO_(2)-pillared multilayer graphene nanocomposites(T-MLGs)via a facile method as follows:dodecanediamine pre-pillaring,ion exchange(Ti4+pillaring),and interlayer in-situ formation of TiO_(...We successfully constructed TiO_(2)-pillared multilayer graphene nanocomposites(T-MLGs)via a facile method as follows:dodecanediamine pre-pillaring,ion exchange(Ti4+pillaring),and interlayer in-situ formation of TiO_(2) by hydrothermal method.TiO_(2) nanoparticles were distributed uniformly on the graphene interlayer.The special structure combined the advantages of graphene and TiO_(2) nanoparticles.As a result,T-MLGs with 64.3wt%TiO_(2) showed the optimum photodegradation rate and adsorption capabilities toward ciprofloxacin.The photodegradation rate of T-MLGs with 64.3wt%TiO_(2) was 78%under light-emitting diode light irradiation for 150 min.Meanwhile,the pseudofirst-order rate constant of T-MLGs with 64.3wt%TiO_(2) was 3.89 times than that of pristine TiO_(2).The composites also exhibited high stability and reusability after five consecutive photocatalytic tests.This work provides a facile method to synthesize semiconductor-pillared graphene nanocomposites by replacing TiO_(2) nanoparticles with other nanoparticles and a feasible means for sustainable utilization of photocatalysts in wastewater control.展开更多
Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were r...Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were reinforced with various amounts of graphene, and the effect of graphene on the strength of these newly developed nanocomposites was studied. The fly ash brick nanocomposite samples were cured as per their standard curing time, and the burnt red soil brick nanocomposite samples were merely dried in the sun instead of being subjected to the traditional heat treatment for days to achieve sufficient strength. The water absorption ability of the fly ash bricks was also discussed. The compressive strength of all of the graphene-reinforced nanocomposite samples was tested, along with that of some standard (without graphene) composite samples with the same dimensions, to evaluate the effects of the addition of various amounts of graphene on the compressive strength of the bricks.展开更多
Ternary TiO2/WO3/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission...Ternary TiO2/WO3/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption--desorption. Both anatase TiO2 and orthorhombic WO3 formed in the nanocomposites, along with a highly disordered overlay of individual graphene nanosheets. Polyhedral and spherical TiO/and WO3 nanoparticles of uniform size 10-30 nm were densely anchored to the graphene sheets. The maximum specific surface area of the products was 144.59 m2·g^-1. The products showed clear abilities for the removal of Rhodamine B in the absence of illumination. Furthermore, the adsorption activity of the products exhibited only a slight decrease after three successive cycles. The results demonstrate that the ternary nanocomposites could be used as a high-efficiency adsorbent for the removal of environmental contaminants.展开更多
This study investigates the effect of graphene oxide(GO)on the mechanical and corrosion behavior,antibacterial performance,and cell response of Mg–Zn–Mn(MZM)nanocomposite.MZM/GO nanocomposites with different amounts...This study investigates the effect of graphene oxide(GO)on the mechanical and corrosion behavior,antibacterial performance,and cell response of Mg–Zn–Mn(MZM)nanocomposite.MZM/GO nanocomposites with different amounts of GO(i.e.,0.5 wt%,1.0 wt%,and1.5 wt%)were fabricated by the semi-powder metallurgy method.The influence of GO on the MZM nanocomposite was analyzed through the hardness,compressive,corrosion,antibacterial,and cytotoxicity tests.The experimental results showed that,with the increase in the amount of GO(0.5 wt%and 1.5 wt%),the hardness value,compressive strength,and antibacterial performance of the MZM nanocomposite increased,whereas the cell viability and osteogenesis level decreased after the addition of 1.5 wt%GO.Moreover,the electrochemical examination results showed that the corrosion behavior of the MZM alloy was significantly enhanced after encapsulation in 0.5 wt%GO.In summary,MZM nanocomposites reinforced with GO can be used for implant applications because of their antibacterial performance and mechanical property.展开更多
The corrosion resistance and wear resistance of metallic biomaterials are critically important for orthopedic hard-tissue replacement applications because the lack of such properties not only adversely affects their m...The corrosion resistance and wear resistance of metallic biomaterials are critically important for orthopedic hard-tissue replacement applications because the lack of such properties not only adversely affects their mechanical integrity but also allows the release of wear debris into the human body.In this study,the potential of zirconium(Zr)as an alloying element and graphene nanoplatelets(GNPs)as a nano-reinforcement material were investigated in relation to improving the tribological performance of pure magnesium(Mg).The GNPs-reinforced Mg matrix nanocomposites(MNCs)were fabricated using powder metallurgy.Results indicate that additions of 0.5 wt.%Zr and0.1 wt.%GNPs to Mg matrices significantly improved the wear resistance by 89%and 92%at 200μN load,60%and 80%at 100μN load,and 94%and 93%at 50μN load,respectively,as compared to the wear resistance of pure Mg.The wear depth and coefficient of friction of the MNC containing 0.5 wt.%Zr and 0.1 wt.%GNPs(Mg0.5 Zr0.1 GNPs MNC)were considerably reduced as compared to pure Mg and Mg0.5 Zr.Our results demonstrate that the Mg0.5 Zr0.1 GNPs MNC is promising for orthopedic applications in relation to its excellent tribological performance.展开更多
The development of carbon nanotubes based materials has been impeded by both their difficult dispersion in the polymer matrix and their high cost. The discovery of graphene and the subsequent development of graphene-b...The development of carbon nanotubes based materials has been impeded by both their difficult dispersion in the polymer matrix and their high cost. The discovery of graphene and the subsequent development of graphene-based polymer nanocomposites is an important addition in the area of nanoscience and technology. In this study the influence of graphene nanoparticles (GNP) in concentrations from 2.0 to 10.0 phr on the dielectric (dielectric permittivity, dielectric loss angle tangent) and microwave (reflection coefficient, attenuation coefficient, shielding effectiveness) properties of nanocomposites on the basis of natural rubber has been investigated in the wide frequency range (1 - 12 GHz). The results achieved allow recommending graphene as a filler for natural rubber based composites to afford specific dielectric and microwave properties, especially when their loading with the much more expensive carbon nanotubes is not possible.展开更多
Molecular dynamics simulations have been performed to explore the underlying synergistic mechanism of pillared graphene or non-covalent connected graphene and carbon nanotubes(CNTs) on the mechanical properties of pol...Molecular dynamics simulations have been performed to explore the underlying synergistic mechanism of pillared graphene or non-covalent connected graphene and carbon nanotubes(CNTs) on the mechanical properties of polyethylene(PE) nanocomposites. By constructing the pillared graphene model and CNTs/graphene model, the effect of the structure, arrangement and dispersion of hybrid fillers on the tensile mechanical properties of PE nanocomposites was studied. The results show that the pillared graphene/PE nanocomposites exhibit higher Young’s modulus, tensile strength and elongation at break than non-covalent connected CNTs/graphene/PE nanocomposites. The pull-out simulations show that pillared graphene by CNTs has both large interfacial load and long displacement due to the mixed modes of shear separation and normal separation. Additionally, pillared graphene can not only inhibit agglomeration but also form a compact effective thickness(stiff layer), consistent with the adsorption behavior and improved interfacial energy between pillared graphene and PE matrix.展开更多
Nowadays with ever increasing demand of energy, developing of alternative power sources is an important issue all over the world. In this respect we have prepared nanocomposites based on metal oxide (titanium oxide) c...Nowadays with ever increasing demand of energy, developing of alternative power sources is an important issue all over the world. In this respect we have prepared nanocomposites based on metal oxide (titanium oxide) coated multiwalled carbon nanotubes (MWCNTs)/polyaniline (PANI) with graphene and without graphene and studied their electrochemical performance. The formation of the polymer in the nanocomposites was confirmed by the Fourier Transform Infrared Spectroscopy (FTIR) study. The morphological characterisations were carried out by the Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). To characterize the prepared nanocomposites electrode, a cyclic voltammetry test for measuring specific capacitance, and an impedance test were conducted. The highest value of specific capacitance obtained for the TiO2 coated MWCNTs/PANI nanocomposite was 443.57 F/g at 2 mV/s scan rate. Upon addition of graphene nanosheet to the TiO2 coated MWCNTs in a weight ratio of (9:1) the specific capacitance value increased to 666.3 F/g at the same scan rate, also resulting in an increase in energy density and power density.展开更多
Featuring exceptional mechanical and functional performance, MWCNTs and graphene(nano)platelets(GNPs or Gn Ps;each platelet below 10 nm in thickness) have been increasingly used for the development of polymer nanocomp...Featuring exceptional mechanical and functional performance, MWCNTs and graphene(nano)platelets(GNPs or Gn Ps;each platelet below 10 nm in thickness) have been increasingly used for the development of polymer nanocomposites. Since MWCNTs are now cost-effective at US$30 per kg for industrial applications, this work starts by briefly reviewing the disentanglement and surface modification of MWCNTs as well as the properties of the resulting polymer nanocomposites. GNPs can be made through the thermal treatment of graphite intercalation compounds followed by ultrasonication;GNPs would have lower cost yet higher electrical conductivity over 1,400 S cmthan MWCNTs. Through proper surface modification and compounding techniques, both types of fillers can reinforce or toughen polymers and simultaneously add anti-static performance. A high ratio of MWCNTs to GNPs would increase the synergy for polymers. Green, solvent-free systhesis methods are desired for polymer nanocomposites. Perspectives on the limitations, current challenges and future prospects are provided.展开更多
The development of convenient method to obtain graphene-based nanocomposites is a key issue for their application. Herein, we described a facile route for synthesizing graphene-Cu and graphene-Cu2 O nanocomposites usi...The development of convenient method to obtain graphene-based nanocomposites is a key issue for their application. Herein, we described a facile route for synthesizing graphene-Cu and graphene-Cu2 O nanocomposites using graphene oxide-Cu O as a precursor. Remarkably, the different nanocomposites could be formed just by varying the reaction temperature and time. This work provides a feasible route for the preparation of graphene-based nanocomposites with various constituents.展开更多
Magnetic reduced graphene oxide(MRGO) nanocomposite was prepared by the chemical coprecipitation method and applied as adsorbent for removing emulsified oil from oily wastewater. SEM, TEM, XRD, FT-IR, VSM and other an...Magnetic reduced graphene oxide(MRGO) nanocomposite was prepared by the chemical coprecipitation method and applied as adsorbent for removing emulsified oil from oily wastewater. SEM, TEM, XRD, FT-IR, VSM and other analytical methods were utilized to characterize the prepared MRGO. The adsorption performance of MRGO was evaluated under different initial adsorbate concentration, MRGO dosage, temperature, and pH value of the solution. The adsorption kinetics and isotherms were investigated. In addition, the MRGO repeatability was also tested. It was found that almost 65%of emulsified oil were removed by MRGO in the first 15 min. The MRGO adsorption capacity and efficiency for removal of adsorbate reached 335.85 mg/g and 92.52% within 60 min, respectively. The adsorption capacity reduced with an increasing MRGO dosage, while increased with the increase of emulsified oil concentration. The adsorption performance of MRGO in the alkaline environment was lower than that in the acidic environment. The adsorption data could well fit to the pseudosecondorder model. The Langmuir model could well describe the isotherm data. The MRGO adsorption capacity was still more than 236.1 mg/g at the sixth regeneration cycle.展开更多
基金Project supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(No.2022R1A2C1004437)。
文摘The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.
基金supported by SERB(Science and Engineering Research Board),New Delhi,India[File.No:EMR/2014/000020].
文摘A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite(glutathione-GO/ZnO)as electrode material for the high-performance piroxicam sensor.The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam(oxidation potential is 0.52 V).Under controlled experimental parameters,the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 μM.The detection limit and sensitivity were calculated as 1.8 μM and 0.2 μA/μM·cm^(2),respectively.Moreover,it offered excellent selectivity,reproducibility,and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration.Finally,the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61265004,51272097,and 11204113)the Nature and Science Fund from Yunnan Province Ministry of Education,China(Grant No.2011C13211708)the Natural Training Project from University of Shanghai for Science and Technology,China(Grant No.14XPM06)
文摘Graphene-ZnO nanocomposites were synthesized successfully through a one-step solvothermal approach. The mor-phology, structure, and composition of the prepared nanocomposites were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), laser micro Raman spectroscopy, and Fourier transform infra-red spec-troscopy (FT-IR). The outcomes confirmed that this approach is comparatively steady, practicable, and operable compared with other reported methods. The electrochemical performance of the graphene-ZnO electrodes was analyzed through cyclic voltammetry, altering-current (AC) impedance, and chronopotentiometry tests. The graphene-ZnO electrodes exhib-ited an improved electrode performance with higher specific capacitance (115 F·g^-1 ), higher electrochemical stability, and higher energy density than the graphene electrodes and most reported graphene-ZnO electrodes. Graphene-ZnO nanocom-posites have a steady reversible charge/discharge behavior, which makes them promising candidates for electrochemical capacitors (ECs).
基金Jiangsu University of Science and Technology for providing financial support under the Research start-up fund for the introduction of young talent at Jiangsu University of Science and Technology (Grant no. 1112932205)High-level Talents Program of Shihezi University (RCZK2021B25)。
文摘In this research study, we have synthesized the bio-capped ZnO/g-C_(3)N_(4) nanocomposites by employing lemon juice(Citrus limon) as a stabilizer and mediator. Fruitfully, lemon juice which contains various acidic functional groups and citric acid has the capability to block the surface of g-C_(3)N_(4) from chemical reactivity and activated the surface of g-C_(3)N_(4) for various reactions. Consequently, the agglomeration behavior and controlled shape of g-C_(3)N_(4) has also been achieved. Our experimental results i.e. XRD,TEM, HRTEM, PL, FS, XPS, and PEC have confirmed that the lemon juice mediated and green g-C_(3)N_(4)(L-CN) have good performances and remarkable visible light photocatalytic activities as compared to the chemically synthesized g-C_(3)N_(4)(CN). Furthermore, the small surface area and low charge separation of g-C_(3)N_(4) is upgraded by coupling with Zn O nanoparticles. It is proved that the coupling of Zn O worked as a facilitator and photoelectron modulator to enhance the charge separation of g-C_(3)N_(4). Compared to pristine lemon-mediated green g-C_(3)N_(4)(L-CN), the most active sample 5Zn O/L-CN showed ~ 5-fold improvement in activities for ciprofloxacin(CIP) and methylene blue(MB) degradation. More specifically,the mineralization process and degradation pathways, and the mineralization process of ciprofloxacin(CIP) and methylene blue(MB) are suggested. Finally, our present novel research work will provide new access to synthesize the eco-friendly and bio-caped green g-C_(3)N_(4)nanomaterials and their employment for pollutants degradation and environmental purification.
基金sponsored by the National Science Foundation (NSF, CMMI-1562907)the GAANN Fellowship for financial support (No. P200A150330)the Navy STEM Fellowship and the GAANN Fellowship for financial support
文摘Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.
文摘Ag/TiO2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of Rh B under visible light irradiation. During the solvothermal process, reduction of graphene oxide and loading of Ag/TiO2nanoparticles on graphene sheets were achieved. Investigation of chemical state of products showed that covering of Ag/TiO2surface with higher weight ratio of graphene resulting in that Ag metals in Ag/TiO2were oxidized to Ag2 O in nanocomposite structure after solvothermal process. Degree of photocatalytic activity enhancement strongly depends on the coverage of Ag/TiO2surface by porous graphene. The sample of 1 wt% porous graphene hybridized Ag/TiO2showed the highest photocatalytic activity, which is related to high migration efficiency of photoinduced of electrons and reduction of electron–hole recombination rate due to high electrical conductivity of graphene. Expanding of absorption to visible light region was ascribed to surface plasmon resonance effect of Ag metals and presence of graphene. Investigation of photocatalytic performance of formic acid as a dye-less organic pollutant showed that dye sensitization effect of Rh B molecules during evaluation of photocatalytic performance was negligible.
基金Funded by the National Natural Science Foundation of China(Nos.21275006,21471001,20905001,21071002,21175001,21271004)
文摘The cobalt sulfide/graphene oxide(CoS/GO) nanocomposite was synthesized by a simple hydrothermal reaction.The products as-synthesized were characterized by XRD,SEM,TEM,BET-BJH and TG.The electrochemical property and impedance of the CoS/GO nanocomposite were studied by cyclic voltammetry and EIS analysis,respectively.The results show that the presence of the GO enhances the electrode conductivity,and then improves the capacitance property of the CoS/GO nanocomposite.The galvanostatic charge/discharge measurement results show that the CoS/GO nanocomposite has a high specific capacitance(550Fg^-1) and long cycle life(over 1 000 cycles).
基金supported by the National Natural Science Foundation of China (21373138)Shanghai Sci. & Tech. Committee (12JC1407200)Program for Changjiang Scholars and Innovative Research Team in University (IRT1269)
文摘An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.
文摘Graphene has attracted considerable interest over recent years due to its intrinsic mechanical, thermal and electrical properties. Incorporation of small quantity of graphene fillers into polymer can create novel nanocomposites with im- proved structural and functional properties. This review introduced the recent progress in fabrication, properties and potential applications of graphene-polymer composites. Recent research clearly confirmed that graphene-polymer na-nocomposites are promising materials with applications ranging from transportation, biomedical systems, sensors, elec-trodes for solar cells and electromagnetic interference. In addition to graphene-polymer nanocomposites, this article also introduced the synergistic effects of hybrid graphene-carbon nanotubes (CNTs) on the properties of composites. Finally, some technical problems associated with the development of these nanocomposites are discussed.
基金the Youth Fund of Hebei Province Education Department,China(No.QN2017117)the Hebei Natural Science Funds for the Joint Research of Iron and Steel,China(Nos.E2019209374,E2015209278).
文摘We successfully constructed TiO_(2)-pillared multilayer graphene nanocomposites(T-MLGs)via a facile method as follows:dodecanediamine pre-pillaring,ion exchange(Ti4+pillaring),and interlayer in-situ formation of TiO_(2) by hydrothermal method.TiO_(2) nanoparticles were distributed uniformly on the graphene interlayer.The special structure combined the advantages of graphene and TiO_(2) nanoparticles.As a result,T-MLGs with 64.3wt%TiO_(2) showed the optimum photodegradation rate and adsorption capabilities toward ciprofloxacin.The photodegradation rate of T-MLGs with 64.3wt%TiO_(2) was 78%under light-emitting diode light irradiation for 150 min.Meanwhile,the pseudofirst-order rate constant of T-MLGs with 64.3wt%TiO_(2) was 3.89 times than that of pristine TiO_(2).The composites also exhibited high stability and reusability after five consecutive photocatalytic tests.This work provides a facile method to synthesize semiconductor-pillared graphene nanocomposites by replacing TiO_(2) nanoparticles with other nanoparticles and a feasible means for sustainable utilization of photocatalysts in wastewater control.
文摘Low-dimensional nanomaterials such as graphene can be used as a reinforcing agent in building materials to enhance the strength and durability. Common building materials burnt red soil bricks and fly ash bricks were reinforced with various amounts of graphene, and the effect of graphene on the strength of these newly developed nanocomposites was studied. The fly ash brick nanocomposite samples were cured as per their standard curing time, and the burnt red soil brick nanocomposite samples were merely dried in the sun instead of being subjected to the traditional heat treatment for days to achieve sufficient strength. The water absorption ability of the fly ash bricks was also discussed. The compressive strength of all of the graphene-reinforced nanocomposite samples was tested, along with that of some standard (without graphene) composite samples with the same dimensions, to evaluate the effects of the addition of various amounts of graphene on the compressive strength of the bricks.
基金financially supported by the National Natural Science Foundation of China (No. 41340037)the Science Foundation for Youth Scholars of State Oceanic Administration (No. 2012508)+2 种基金the Scientific Research Program of Shandong Province (No. 2013G0021701)the Natural Science Foundation of Shandong Province, China (No. ZR2011BL012 and ZR2012EMM015)the Scientific Research Program of Qingdao (No.11-2-4-3-15-jch)
文摘Ternary TiO2/WO3/graphene (TWG) nanocomposites were prepared by a facile salt-ultrasonic assisted hydrothermal method. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption--desorption. Both anatase TiO2 and orthorhombic WO3 formed in the nanocomposites, along with a highly disordered overlay of individual graphene nanosheets. Polyhedral and spherical TiO/and WO3 nanoparticles of uniform size 10-30 nm were densely anchored to the graphene sheets. The maximum specific surface area of the products was 144.59 m2·g^-1. The products showed clear abilities for the removal of Rhodamine B in the absence of illumination. Furthermore, the adsorption activity of the products exhibited only a slight decrease after three successive cycles. The results demonstrate that the ternary nanocomposites could be used as a high-efficiency adsorbent for the removal of environmental contaminants.
文摘This study investigates the effect of graphene oxide(GO)on the mechanical and corrosion behavior,antibacterial performance,and cell response of Mg–Zn–Mn(MZM)nanocomposite.MZM/GO nanocomposites with different amounts of GO(i.e.,0.5 wt%,1.0 wt%,and1.5 wt%)were fabricated by the semi-powder metallurgy method.The influence of GO on the MZM nanocomposite was analyzed through the hardness,compressive,corrosion,antibacterial,and cytotoxicity tests.The experimental results showed that,with the increase in the amount of GO(0.5 wt%and 1.5 wt%),the hardness value,compressive strength,and antibacterial performance of the MZM nanocomposite increased,whereas the cell viability and osteogenesis level decreased after the addition of 1.5 wt%GO.Moreover,the electrochemical examination results showed that the corrosion behavior of the MZM alloy was significantly enhanced after encapsulation in 0.5 wt%GO.In summary,MZM nanocomposites reinforced with GO can be used for implant applications because of their antibacterial performance and mechanical property.
基金financial support for this research by the Australian Research Council(ARC)through the Future Fellowship(FT160100252)the Discovery Project(DP170102557)。
文摘The corrosion resistance and wear resistance of metallic biomaterials are critically important for orthopedic hard-tissue replacement applications because the lack of such properties not only adversely affects their mechanical integrity but also allows the release of wear debris into the human body.In this study,the potential of zirconium(Zr)as an alloying element and graphene nanoplatelets(GNPs)as a nano-reinforcement material were investigated in relation to improving the tribological performance of pure magnesium(Mg).The GNPs-reinforced Mg matrix nanocomposites(MNCs)were fabricated using powder metallurgy.Results indicate that additions of 0.5 wt.%Zr and0.1 wt.%GNPs to Mg matrices significantly improved the wear resistance by 89%and 92%at 200μN load,60%and 80%at 100μN load,and 94%and 93%at 50μN load,respectively,as compared to the wear resistance of pure Mg.The wear depth and coefficient of friction of the MNC containing 0.5 wt.%Zr and 0.1 wt.%GNPs(Mg0.5 Zr0.1 GNPs MNC)were considerably reduced as compared to pure Mg and Mg0.5 Zr.Our results demonstrate that the Mg0.5 Zr0.1 GNPs MNC is promising for orthopedic applications in relation to its excellent tribological performance.
文摘The development of carbon nanotubes based materials has been impeded by both their difficult dispersion in the polymer matrix and their high cost. The discovery of graphene and the subsequent development of graphene-based polymer nanocomposites is an important addition in the area of nanoscience and technology. In this study the influence of graphene nanoparticles (GNP) in concentrations from 2.0 to 10.0 phr on the dielectric (dielectric permittivity, dielectric loss angle tangent) and microwave (reflection coefficient, attenuation coefficient, shielding effectiveness) properties of nanocomposites on the basis of natural rubber has been investigated in the wide frequency range (1 - 12 GHz). The results achieved allow recommending graphene as a filler for natural rubber based composites to afford specific dielectric and microwave properties, especially when their loading with the much more expensive carbon nanotubes is not possible.
基金the financial support from the National Key Research and Development Program of China (grant no. 2020YFA0711800)National Natural Science Foundation of China (grant no. 11802027, 51973033)+2 种基金State Key Laboratory of Explosion Science and Technology (grant no. YPJH20-6, QNKT20-01, JCRC18-01)BITBRFFR Joint Research Program (BITBLR2020018)Beijing Institute of Technology Research Fund。
文摘Molecular dynamics simulations have been performed to explore the underlying synergistic mechanism of pillared graphene or non-covalent connected graphene and carbon nanotubes(CNTs) on the mechanical properties of polyethylene(PE) nanocomposites. By constructing the pillared graphene model and CNTs/graphene model, the effect of the structure, arrangement and dispersion of hybrid fillers on the tensile mechanical properties of PE nanocomposites was studied. The results show that the pillared graphene/PE nanocomposites exhibit higher Young’s modulus, tensile strength and elongation at break than non-covalent connected CNTs/graphene/PE nanocomposites. The pull-out simulations show that pillared graphene by CNTs has both large interfacial load and long displacement due to the mixed modes of shear separation and normal separation. Additionally, pillared graphene can not only inhibit agglomeration but also form a compact effective thickness(stiff layer), consistent with the adsorption behavior and improved interfacial energy between pillared graphene and PE matrix.
文摘Nowadays with ever increasing demand of energy, developing of alternative power sources is an important issue all over the world. In this respect we have prepared nanocomposites based on metal oxide (titanium oxide) coated multiwalled carbon nanotubes (MWCNTs)/polyaniline (PANI) with graphene and without graphene and studied their electrochemical performance. The formation of the polymer in the nanocomposites was confirmed by the Fourier Transform Infrared Spectroscopy (FTIR) study. The morphological characterisations were carried out by the Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). To characterize the prepared nanocomposites electrode, a cyclic voltammetry test for measuring specific capacitance, and an impedance test were conducted. The highest value of specific capacitance obtained for the TiO2 coated MWCNTs/PANI nanocomposite was 443.57 F/g at 2 mV/s scan rate. Upon addition of graphene nanosheet to the TiO2 coated MWCNTs in a weight ratio of (9:1) the specific capacitance value increased to 666.3 F/g at the same scan rate, also resulting in an increase in energy density and power density.
基金financial support by the Australian Research Council (LP180100005 & DP200101737)。
文摘Featuring exceptional mechanical and functional performance, MWCNTs and graphene(nano)platelets(GNPs or Gn Ps;each platelet below 10 nm in thickness) have been increasingly used for the development of polymer nanocomposites. Since MWCNTs are now cost-effective at US$30 per kg for industrial applications, this work starts by briefly reviewing the disentanglement and surface modification of MWCNTs as well as the properties of the resulting polymer nanocomposites. GNPs can be made through the thermal treatment of graphite intercalation compounds followed by ultrasonication;GNPs would have lower cost yet higher electrical conductivity over 1,400 S cmthan MWCNTs. Through proper surface modification and compounding techniques, both types of fillers can reinforce or toughen polymers and simultaneously add anti-static performance. A high ratio of MWCNTs to GNPs would increase the synergy for polymers. Green, solvent-free systhesis methods are desired for polymer nanocomposites. Perspectives on the limitations, current challenges and future prospects are provided.
基金Funded by the Jiangsu Funds for Distinguished Young Scientists(No.BK2012035)Program for New Century Excellent Talents in University(No.NCET-11-0834)the National Natural Science Foundation of China(No.21206075)
文摘The development of convenient method to obtain graphene-based nanocomposites is a key issue for their application. Herein, we described a facile route for synthesizing graphene-Cu and graphene-Cu2 O nanocomposites using graphene oxide-Cu O as a precursor. Remarkably, the different nanocomposites could be formed just by varying the reaction temperature and time. This work provides a feasible route for the preparation of graphene-based nanocomposites with various constituents.
基金funded by the Major National Science and Technology Projects of China(Grant No.2016ZX05040-003)the Top Talents Project of China University of Petroleum(grant No.2015011)
文摘Magnetic reduced graphene oxide(MRGO) nanocomposite was prepared by the chemical coprecipitation method and applied as adsorbent for removing emulsified oil from oily wastewater. SEM, TEM, XRD, FT-IR, VSM and other analytical methods were utilized to characterize the prepared MRGO. The adsorption performance of MRGO was evaluated under different initial adsorbate concentration, MRGO dosage, temperature, and pH value of the solution. The adsorption kinetics and isotherms were investigated. In addition, the MRGO repeatability was also tested. It was found that almost 65%of emulsified oil were removed by MRGO in the first 15 min. The MRGO adsorption capacity and efficiency for removal of adsorbate reached 335.85 mg/g and 92.52% within 60 min, respectively. The adsorption capacity reduced with an increasing MRGO dosage, while increased with the increase of emulsified oil concentration. The adsorption performance of MRGO in the alkaline environment was lower than that in the acidic environment. The adsorption data could well fit to the pseudosecondorder model. The Langmuir model could well describe the isotherm data. The MRGO adsorption capacity was still more than 236.1 mg/g at the sixth regeneration cycle.