Morphology-controlled synthesis of copper vanadate nanocrystals is of great significance in electrochemical sensing applications.A facile hydrothermal process for synthesizing copper vanadate nanocrystals with various...Morphology-controlled synthesis of copper vanadate nanocrystals is of great significance in electrochemical sensing applications.A facile hydrothermal process for synthesizing copper vanadate nanocrystals with various morphologies(e.g.,nanoparticles,nanobelts and nanoflowers)was reported.Phase,morphology and electrochemical performance of the as-synthesized copper vanadate nanocrystals were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and cyclic-voltammogram(CV)techniques.The results revealed that the morphologies of the Cu3V2O7(OH)2·2H2O(CVOH)nanocrystals could be controlled by changing copper salts,surfactants and pH values.The CVOH samples showed enhanced electrochemical response to ascorbic acid.Comparatively,the CVOH nanobelts had the higher electrochemical sensing performance than those of CVOH nanoparticles and nanoflowers.The CVOH-nanobelts-modified GCEs had a linear relationship between the peak currents in their CVs and ascorbic acid concentration.The CVOH nanocrystals can be used as potential electrochemical active materials for the determination of ascorbic acid.展开更多
The mixed metal/metal sulphide(Ag@CoS)with reduced graphene oxide(rGO)nanocomposite(Ag@CoS/rGO)was synthesized for the possible electrode in supercapacitors.Ag@CoS was successfully deposited on the rGO nanosheets by h...The mixed metal/metal sulphide(Ag@CoS)with reduced graphene oxide(rGO)nanocomposite(Ag@CoS/rGO)was synthesized for the possible electrode in supercapacitors.Ag@CoS was successfully deposited on the rGO nanosheets by hydrothermal method,implying the growth of 2D Ag and CoS-based hexagonal-like structure on the rGO framework.The synthesized nanocomposite was subjected to structural,morphological and electrochemical studies.The XRD results show that the prepared nanocomposite material exhibits a combination of hexagonal and cubic phase due to the presence of CoS and Ag phases together.The band appearing at nearly 470.33 cm^−1 in FTIR spectra can be ascribed to the absorption of S—S bond in the Ag@CoS/rGO nanocomposite.The clear hexagonal structure was analysed by SEM and TEM with the grain sizes ranging from nanometer to micrometer.The electrode material exhibits excellent cyclic stability with a specific capacitance of 1580 F/g at a current density of 0.5 A/g without any loss of capacitive retention even after 1000 cycles.Based on the electrochemical performance,it can be inferred that the prepared novel nanocomposite material is very suitable for using as an electrode for electrochemical supercapacitor applications.展开更多
A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed cou...A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.展开更多
A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nicke...A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.展开更多
基金Projects(51404213,51404214,51574205,51172211)supported by the National Natural Science Foundation of ChinaProjects(14HASTIT011,154100510003)supported by the Program for University Science and Technology Innovation Talents of Henan Province,China+1 种基金Projects(2013M531682,2014T70682)supported by the China Postdoctoral Science FundProject(1421324065)supported by the Development Fund for Outstanding Young Teachers of Zhengzhou University,China
文摘Morphology-controlled synthesis of copper vanadate nanocrystals is of great significance in electrochemical sensing applications.A facile hydrothermal process for synthesizing copper vanadate nanocrystals with various morphologies(e.g.,nanoparticles,nanobelts and nanoflowers)was reported.Phase,morphology and electrochemical performance of the as-synthesized copper vanadate nanocrystals were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM)and cyclic-voltammogram(CV)techniques.The results revealed that the morphologies of the Cu3V2O7(OH)2·2H2O(CVOH)nanocrystals could be controlled by changing copper salts,surfactants and pH values.The CVOH samples showed enhanced electrochemical response to ascorbic acid.Comparatively,the CVOH nanobelts had the higher electrochemical sensing performance than those of CVOH nanoparticles and nanoflowers.The CVOH-nanobelts-modified GCEs had a linear relationship between the peak currents in their CVs and ascorbic acid concentration.The CVOH nanocrystals can be used as potential electrochemical active materials for the determination of ascorbic acid.
文摘The mixed metal/metal sulphide(Ag@CoS)with reduced graphene oxide(rGO)nanocomposite(Ag@CoS/rGO)was synthesized for the possible electrode in supercapacitors.Ag@CoS was successfully deposited on the rGO nanosheets by hydrothermal method,implying the growth of 2D Ag and CoS-based hexagonal-like structure on the rGO framework.The synthesized nanocomposite was subjected to structural,morphological and electrochemical studies.The XRD results show that the prepared nanocomposite material exhibits a combination of hexagonal and cubic phase due to the presence of CoS and Ag phases together.The band appearing at nearly 470.33 cm^−1 in FTIR spectra can be ascribed to the absorption of S—S bond in the Ag@CoS/rGO nanocomposite.The clear hexagonal structure was analysed by SEM and TEM with the grain sizes ranging from nanometer to micrometer.The electrode material exhibits excellent cyclic stability with a specific capacitance of 1580 F/g at a current density of 0.5 A/g without any loss of capacitive retention even after 1000 cycles.Based on the electrochemical performance,it can be inferred that the prepared novel nanocomposite material is very suitable for using as an electrode for electrochemical supercapacitor applications.
基金Projects(51474251,51874351) supported by the National Natural Science Foundation of China
文摘A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.
基金Project(KJ2012A045) supported by the Natural Science Foundation of Education Commission of Anhui Province,China
文摘A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.
