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
Fe（3–x）O4 raspberry shaped nanostructures/graphene nanocomposites were synthesized by a one-step polyol-solvothermal method to be tested as electrode materials for Li-ion battery（LIB）. Indeed, Fe（3–x）O4 raspbe...Fe（3–x）O4 raspberry shaped nanostructures/graphene nanocomposites were synthesized by a one-step polyol-solvothermal method to be tested as electrode materials for Li-ion battery（LIB）. Indeed, Fe（3–x）O4 raspberry shaped nanostructures consist of original oriented aggregates of Fe（3–x）O4 magnetite nanocrystals, ensuring a low oxidation state of magnetite and a hollow and porous structure, which has been easily combined with graphene sheets. The resulting nanocomposite powder displays a very homogeneous spatial distribution of Fe（3–x）O4 nanostructures at the surface of the graphene sheets. These original nanostructures and their strong interaction with the graphene sheets resulted in very small capacity fading upon Li＋ion intercalation. Reversible capacity, as high as 660 m Ah/g, makes this material promising for anode in Li-ion batteries application.展开更多
In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction.Additionally,the tendency of In_...In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction.Additionally,the tendency of In_(2)O_(3)particles to agglomerate during synthesis further limits the exposure of active sites.Here we address these issues by leveraging the template effect of graphene oxide and employing InBDC as a self-sacrificing template for the pyrolysis synthesis of In_(2)O_(3)@C.The resulting In_(2)O_(3)@C/rGO-600 material features In_(2)O_(3)@C nanocubes uniformly anchored on a support of reduced graphene oxide(rGO),significantly enhancing the active sites exposure.The conductive rGO network facilitates charge transfer during electrocatalysis,and the presence of oxygen vacancies generated during pyrolysis,combined with the strong electron-donating ability of rGO,enhances the adsorption and activation of CO_(2).In performance evaluation,In_(2)O_(3)@C/rGO-600 exhibits a remarkable HCOOH Faradaic efficiency exceeding 94.0%over a broad potential window of−0.7 to−1.0 V(vs.reversible hydrogen electrode(RHE)),with the highest value of 97.9%at−0.9 V(vs.RHE)in a H-cell.Moreover,the material demonstrates an excellent cathodic energy efficiency of 71.6%at−0.7 V(vs.RHE).The study underscores the efficacy of uniformly anchoring metal oxide nanoparticles onto rGO for enhancing the electrocatalytic CO_(2)reduction performance of materials.展开更多
Adsorbent has been widely used for the recovery and enrichment of rare metals from waste water.Herein,a graphene-based adsorbent,graphene oxide/Fe_(3)O_(4)(GO/Fe_(3)O_(4))nanocomposite,was prepared by a facile hydroth...Adsorbent has been widely used for the recovery and enrichment of rare metals from waste water.Herein,a graphene-based adsorbent,graphene oxide/Fe_(3)O_(4)(GO/Fe_(3)O_(4))nanocomposite,was prepared by a facile hydrothermal method,and characterized by X-ray diffraction,Scanning Electron Microscope,X-ray Photoelectron Spectroscopy,Zeta potential and magnetization.The material has been explored for the recovery of In from simulated waste water.The test results show that the nanocomposite has a reasonable adsorption capacity on indium in a wide pH range,e.g.,the adsorption percent and quantity of In(Ⅲ)from the aqueous solutions at pH=4 and C0=50 mg·L^(-1)are 91%and 43.98 mg·L^(-1),respectively.In addition,the nanocomposites maintain a 75.5%cycling capacity and a 71%removal efficiency after five continuous cycles due to their novel properties of high specific surface area and superparamagnetism.The pseudo-second-order adsorption model can be used to interpret the kinetic data.High adsorption efficiency and good reusability can make the nanocomposite a promising adsorbent for recovery of In(Ⅲ).展开更多
A 2D layer Cu(Ⅱ) coordination polymer [Cu(npth)(H_(2)O)]n(1) was crystallized from a mixture of 3-nitrophthalic acid and Cu(OAc)_(2)·H_(2)O in water under room temperature and structurally characterized by singl...A 2D layer Cu(Ⅱ) coordination polymer [Cu(npth)(H_(2)O)]n(1) was crystallized from a mixture of 3-nitrophthalic acid and Cu(OAc)_(2)·H_(2)O in water under room temperature and structurally characterized by single-crystal X-ray diffraction, FT-IR and TGA. Compound 1 was applied to make a nanocomposite with graphene oxide(GO). A highly dispersible and stable nanocomposite of Cu(npth)-GO was successfully synthesized by a simple ultrasonication method. SEM, TEM, UV-vis, FT-IR and TGA were used to characterize the morphology and structure of the prepared composite. In accordance with the characterization results, we suspected that the binding mechanism of Cu(npth) and GO was assigned to be the cooperative interaction of Cu–O coordination, π-π stacking and hydrogen bonding.展开更多
Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been perfo...Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been performed through the sol–gel method. Then, platinum（Pt） nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites. X-ray diffraction（XRD） findings exhibit a formation of monoclinic and triclinic WO3 phases. Transmission Electron Microscope（TEM） images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of Methylene Blue（MB） as a probe molecule under visible light illumination.The findings showed that mesoporous Pt/WO3, WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3. The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO3, WO3-GO, and Pt/WO3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.展开更多
The advent of“intelligent era”brings our life more convenience,but the electromagnetic radiation sur-rounding us not only greatly threatens human health,also makes information leakage and hidden trouble to national ...The advent of“intelligent era”brings our life more convenience,but the electromagnetic radiation sur-rounding us not only greatly threatens human health,also makes information leakage and hidden trouble to national defense security.Hence,it is very urgent to develop novel electromagnetic wave absorption materials with lightweight,strong absorption,tunable absorption frequency and broad band absorption.Herein,a novel electromagnetic wave absorber is obtained by constructing La_(0.8)CoO_(3)-rGO nanocompos-ite,where La_(0.8)CoO_(3)nanoparticles are anchored on graphene nanosheets by the electrostatic interaction between GO and La_(0.8)CoO_(3).The effect of hybridization ratio of La_(0.8)CoO_(3)and rGO on microwave ab-sorption properties is carefully studied.The optimal reflection loss of La_(0.8)CoO_(3)-rGO nanocomposite can reach-62.34 dB with the maximum effective bandwidth of 6.08 GHz,presenting 48.78%and 245.45%increment compared to bare La_(0.8)CoO_(3)nanoparticles,respectively.The effective absorption bandwidth covers a broad electromagnetic wave absorption band from Ku band to the C band by tailoring thickness of the absorbers from 2.4 mm to 4.4 mm.The fascinating electromagnetic wave absorption performance is attributed to the synergy effect of La_(0.8)CoO_(3)and rGO,which integrates magnetic and dielectric loss caused by resonance,conductance,relaxation,and scattering loss.This result confirms that La_(0.8)CoO_(3)-rGO nanocomposite is potential candidates toward high-efficiency microwave absorbers and provides a valuable pathway for designing high-performance microwave attenuation materials in the future.展开更多
An efficient, controllable, and facile two-step synthetic strategy to prepare graphene-based nanocomposites is proposed. A series of Fe3O4-decorated reduced graphene oxide （Fe3O4@RGO） nanocomposites incorporating Fe...An efficient, controllable, and facile two-step synthetic strategy to prepare graphene-based nanocomposites is proposed. A series of Fe3O4-decorated reduced graphene oxide （Fe3O4@RGO） nanocomposites incorporating Fe3O4 nanocrystals of various sizes were prepared by an ethanothermal method using graphene oxide （GO） and monodisperse Fe3O4 nanocrystals with diameters ranging from 4 to 10 nm. The morphologies and microstructures of the as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, nitrogen adsorption measurements, and transmission electron microscopy. The results show that GO can be reduced to graphene during the ethanothermal process, and that the Fe3O4 nanocrystals are well dispersed on the graphene sheets generated in the process. The analysis of the electrochemical properties of the Fe3O4@RGO materials shows that nanocomposites prepared with Fe3O4 nanocrystals of different sizes exhibit different electrochemical performances. Among all samples, FegO4@RGO prepared with Fe3O4 nanocrystals of 6 nm diameter possessed the highest specific capacitance of 481 F/g at 1 A/g, highlighting the excellent capability of this material. This work illustrates a promising route to develop graphene-based nanocomposite materials with a wide range of potential applications.展开更多
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.
基金supported by the funding from the European Research Council(ERCAdvanced Grant,ERC-2011-AdG,Project 291543-IONACES)+2 种基金the Materials Institute Carnot Alsace(MICA)from the Direction Générale de l’Armement(DGA)French-German Research Institute of Saint-Louis(ISL)
文摘Fe（3–x）O4 raspberry shaped nanostructures/graphene nanocomposites were synthesized by a one-step polyol-solvothermal method to be tested as electrode materials for Li-ion battery（LIB）. Indeed, Fe（3–x）O4 raspberry shaped nanostructures consist of original oriented aggregates of Fe（3–x）O4 magnetite nanocrystals, ensuring a low oxidation state of magnetite and a hollow and porous structure, which has been easily combined with graphene sheets. The resulting nanocomposite powder displays a very homogeneous spatial distribution of Fe（3–x）O4 nanostructures at the surface of the graphene sheets. These original nanostructures and their strong interaction with the graphene sheets resulted in very small capacity fading upon Li＋ion intercalation. Reversible capacity, as high as 660 m Ah/g, makes this material promising for anode in Li-ion batteries application.
基金Joint Key Program of National Natural Science Foundation of China(No.U22B20147).
文摘In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the reaction.Additionally,the tendency of In_(2)O_(3)particles to agglomerate during synthesis further limits the exposure of active sites.Here we address these issues by leveraging the template effect of graphene oxide and employing InBDC as a self-sacrificing template for the pyrolysis synthesis of In_(2)O_(3)@C.The resulting In_(2)O_(3)@C/rGO-600 material features In_(2)O_(3)@C nanocubes uniformly anchored on a support of reduced graphene oxide(rGO),significantly enhancing the active sites exposure.The conductive rGO network facilitates charge transfer during electrocatalysis,and the presence of oxygen vacancies generated during pyrolysis,combined with the strong electron-donating ability of rGO,enhances the adsorption and activation of CO_(2).In performance evaluation,In_(2)O_(3)@C/rGO-600 exhibits a remarkable HCOOH Faradaic efficiency exceeding 94.0%over a broad potential window of−0.7 to−1.0 V(vs.reversible hydrogen electrode(RHE)),with the highest value of 97.9%at−0.9 V(vs.RHE)in a H-cell.Moreover,the material demonstrates an excellent cathodic energy efficiency of 71.6%at−0.7 V(vs.RHE).The study underscores the efficacy of uniformly anchoring metal oxide nanoparticles onto rGO for enhancing the electrocatalytic CO_(2)reduction performance of materials.
基金supported by the FJIRSM&IUE Joint Research Fund(No.RHZX-2018-006)。
文摘Adsorbent has been widely used for the recovery and enrichment of rare metals from waste water.Herein,a graphene-based adsorbent,graphene oxide/Fe_(3)O_(4)(GO/Fe_(3)O_(4))nanocomposite,was prepared by a facile hydrothermal method,and characterized by X-ray diffraction,Scanning Electron Microscope,X-ray Photoelectron Spectroscopy,Zeta potential and magnetization.The material has been explored for the recovery of In from simulated waste water.The test results show that the nanocomposite has a reasonable adsorption capacity on indium in a wide pH range,e.g.,the adsorption percent and quantity of In(Ⅲ)from the aqueous solutions at pH=4 and C0=50 mg·L^(-1)are 91%and 43.98 mg·L^(-1),respectively.In addition,the nanocomposites maintain a 75.5%cycling capacity and a 71%removal efficiency after five continuous cycles due to their novel properties of high specific surface area and superparamagnetism.The pseudo-second-order adsorption model can be used to interpret the kinetic data.High adsorption efficiency and good reusability can make the nanocomposite a promising adsorbent for recovery of In(Ⅲ).
基金Supported by the National Natural Science Foundation of China (No.22001064)the Natural Science Foundation of Hunan Province (No.2020JJ4155)+1 种基金the 2020 Hunan Province College Students’Innovation Entrepreneurship Training Program (No.3373)the Scientific Research Project of Hunan Province Department of Education (No.20B105)。
文摘A 2D layer Cu(Ⅱ) coordination polymer [Cu(npth)(H_(2)O)]n(1) was crystallized from a mixture of 3-nitrophthalic acid and Cu(OAc)_(2)·H_(2)O in water under room temperature and structurally characterized by single-crystal X-ray diffraction, FT-IR and TGA. Compound 1 was applied to make a nanocomposite with graphene oxide(GO). A highly dispersible and stable nanocomposite of Cu(npth)-GO was successfully synthesized by a simple ultrasonication method. SEM, TEM, UV-vis, FT-IR and TGA were used to characterize the morphology and structure of the prepared composite. In accordance with the characterization results, we suspected that the binding mechanism of Cu(npth) and GO was assigned to be the cooperative interaction of Cu–O coordination, π-π stacking and hydrogen bonding.
文摘Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters. Here, one pot synthesis of mesoporous WO3 and WO3-graphene oxide（GO） nanocomposites has been performed through the sol–gel method. Then, platinum（Pt） nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites. X-ray diffraction（XRD） findings exhibit a formation of monoclinic and triclinic WO3 phases. Transmission Electron Microscope（TEM） images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ~ 10 nm and 20–50 nm, respectively. The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of Methylene Blue（MB） as a probe molecule under visible light illumination.The findings showed that mesoporous Pt/WO3, WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3. The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3, 2 and 1.15 times greater than those by mesoporous WO3, WO3-GO, and Pt/WO3, respectively. The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets, in addition to the Pt nanoparticles that act as active sites for O2 reduction, which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.
基金supported by Natural Science Foundation of China(Nos.12074095,52273257,52177014,and 51977009)Heilongjiang Provincial Science Foundation for Distin-guished Young Scholars(No.JQ2022A002)2020 Central Govern-ment’s Plan to Support the Talent Training Project of the Reform and Development Fund of Local Universities(No.2020YQ02).
文摘The advent of“intelligent era”brings our life more convenience,but the electromagnetic radiation sur-rounding us not only greatly threatens human health,also makes information leakage and hidden trouble to national defense security.Hence,it is very urgent to develop novel electromagnetic wave absorption materials with lightweight,strong absorption,tunable absorption frequency and broad band absorption.Herein,a novel electromagnetic wave absorber is obtained by constructing La_(0.8)CoO_(3)-rGO nanocompos-ite,where La_(0.8)CoO_(3)nanoparticles are anchored on graphene nanosheets by the electrostatic interaction between GO and La_(0.8)CoO_(3).The effect of hybridization ratio of La_(0.8)CoO_(3)and rGO on microwave ab-sorption properties is carefully studied.The optimal reflection loss of La_(0.8)CoO_(3)-rGO nanocomposite can reach-62.34 dB with the maximum effective bandwidth of 6.08 GHz,presenting 48.78%and 245.45%increment compared to bare La_(0.8)CoO_(3)nanoparticles,respectively.The effective absorption bandwidth covers a broad electromagnetic wave absorption band from Ku band to the C band by tailoring thickness of the absorbers from 2.4 mm to 4.4 mm.The fascinating electromagnetic wave absorption performance is attributed to the synergy effect of La_(0.8)CoO_(3)and rGO,which integrates magnetic and dielectric loss caused by resonance,conductance,relaxation,and scattering loss.This result confirms that La_(0.8)CoO_(3)-rGO nanocomposite is potential candidates toward high-efficiency microwave absorbers and provides a valuable pathway for designing high-performance microwave attenuation materials in the future.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 21521091, 21390393, U1463202, 21573119, and 21590792）, the National Key Research and Development Program of China （No. 2016YFA0202801） and Fundamental Research Funds for the Central Universities （No. 2015RC070）.
文摘An efficient, controllable, and facile two-step synthetic strategy to prepare graphene-based nanocomposites is proposed. A series of Fe3O4-decorated reduced graphene oxide （Fe3O4@RGO） nanocomposites incorporating Fe3O4 nanocrystals of various sizes were prepared by an ethanothermal method using graphene oxide （GO） and monodisperse Fe3O4 nanocrystals with diameters ranging from 4 to 10 nm. The morphologies and microstructures of the as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, nitrogen adsorption measurements, and transmission electron microscopy. The results show that GO can be reduced to graphene during the ethanothermal process, and that the Fe3O4 nanocrystals are well dispersed on the graphene sheets generated in the process. The analysis of the electrochemical properties of the Fe3O4@RGO materials shows that nanocomposites prepared with Fe3O4 nanocrystals of different sizes exhibit different electrochemical performances. Among all samples, FegO4@RGO prepared with Fe3O4 nanocrystals of 6 nm diameter possessed the highest specific capacitance of 481 F/g at 1 A/g, highlighting the excellent capability of this material. This work illustrates a promising route to develop graphene-based nanocomposite materials with a wide range of potential applications.
