A sponge network-shaped Mn_(3)O_(4) material is synthesized by a one-pot metal organic framework-combustion(MOF-C)technique for Li-ion battery anodes with improved performance.The as-synthesized ordered sponge network...A sponge network-shaped Mn_(3)O_(4) material is synthesized by a one-pot metal organic framework-combustion(MOF-C)technique for Li-ion battery anodes with improved performance.The as-synthesized ordered sponge network morphology is characterized by various techniques,such as powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,X-ray photoelectron spectroscopy,and N_(2) adsorption–desorption measurements.The one-pot synthesized Mn_(3)O_(4) material shows a uniform amorphous graphitic carbon coating with few-nanometer thickness on the surface.This anode shows an initial discharge capacity of 1186 mA h g^(−1) and a reversible capacity of 768 mA h g^(−1) is maintained at an applied current density of 200 mA g^(−1) after 100 cycles.Sustained reversible capacities of 651 and 592 mA h g^(−1) are measured for the other two different current densities of 500 and 700 mA g^(−1),respectively,after 120 cycles,demonstrating the high stability of the anode.This unique morphology appears to contribute to the significantly high rate performance,as observed from the retained reversible capacity of 155 mA h g^(−1) at a very high current density of 10000 mA g^(−1),which is maintained for the next two subsequent sequences with a notable recovered capacity of 700 mA h g^(−1) for an intermediate current density of 400 mA g^(−1) after 175 cycles.展开更多
In this paper,CuO–CdS composites were synthesized by a facile two-step solvothermal method.The composite materials were characterized by a series of systematical measures,such as X-ray diffraction,Fourier transform i...In this paper,CuO–CdS composites were synthesized by a facile two-step solvothermal method.The composite materials were characterized by a series of systematical measures,such as X-ray diffraction,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,scanning electron microscopy and transmission electron microscopy.Through detailed experiments,it was observed that the shape of the as-prepared materials could be tailored by varying the CuO content in composites.The experimental results manifested that CdS decorated with 0.05 at%CuO presents superior performance including response/recovery speed,detection limit,optimum operating temperature,and sensitivity in comparison with pure CdS.The possible mechanisms of enhanced sensing properties were discussed in detail.At the interface of the two different material surfaces,the capacity of surface-adsorbed oxygen was elevated,which can be attributed to the formation of the p–n heterojunction between CdS and CuO.In conclusion,the functionalization of CuO with CdS may be a promising method to enhance gassensing properties.展开更多
Lithium-rich layered oxide cathodes have an advantage of high energy density.However,continuous capacity fading and voltage hysteresis have largely restricted their practical application.In this work,we investigated i...Lithium-rich layered oxide cathodes have an advantage of high energy density.However,continuous capacity fading and voltage hysteresis have largely restricted their practical application.In this work,we investigated in depth the voltage-fading mechanism of Li-rich materials by in situ Raman spectroscopy,X-ray absorption near edge structure(XANES)spectroscopy,andhigh-resolution transmission electron microscopy(HRTEM).展开更多
Redox activity of copper species immobilized poly(o-aminophenol)/multi-walled carbon nanotube(Cu@MWCNT-POAP)composite is reported for direct electrocatalysis towards detection of H_(2)O_(2).The Cu@MWCNT-POAP composite...Redox activity of copper species immobilized poly(o-aminophenol)/multi-walled carbon nanotube(Cu@MWCNT-POAP)composite is reported for direct electrocatalysis towards detection of H_(2)O_(2).The Cu@MWCNT-POAP composite was prepared by a single step in situ electrochemical method.The as-prepared Cu@MWCNT-POAP composites were characterized by field emission scanning electron microscopy,Fourier transform infrared spectroscopy,Raman spectroscopy,X-ray diffraction,and electrochemical impedance spectroscopy.Cyclic voltammetry(CV)studies highlighted the good redox behavior of the Cu@MWCNT-POAP composite resulting from direct electron transfer behavior of the copper redox couple(Cu^(2+)/Cu^(+)).The Cu@MWCNT-POAP composite displayed superior electrocatalytic activity and high performance towards detection of H_(2)O_(2)because of its large surface area and homogenous immobilization of Cu species on the MWCNT-POAP composite.The analytical sensitivity and detection limit of the sensor were 831μA mM^(-1)cm^(-2)and 30 nM,respectively.In addition,bio-catalytic activity of the sensor was evaluated using the Michaelis-Menten constant.The Cu@MWCNT-POAP composite showed excellent stability and reproducibility,and good recoveries for determination of H_(2)O_(2)in milk,bleach cream,and contact lens solutions.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(2014R1A2A1A10050821)supported by the Global Frontier Program through the Global Frontier Hybrid Interface Materials(GFHIM)of the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT&Future Planning(2013M3A6B1078875)or(2013-073298).
文摘A sponge network-shaped Mn_(3)O_(4) material is synthesized by a one-pot metal organic framework-combustion(MOF-C)technique for Li-ion battery anodes with improved performance.The as-synthesized ordered sponge network morphology is characterized by various techniques,such as powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,X-ray photoelectron spectroscopy,and N_(2) adsorption–desorption measurements.The one-pot synthesized Mn_(3)O_(4) material shows a uniform amorphous graphitic carbon coating with few-nanometer thickness on the surface.This anode shows an initial discharge capacity of 1186 mA h g^(−1) and a reversible capacity of 768 mA h g^(−1) is maintained at an applied current density of 200 mA g^(−1) after 100 cycles.Sustained reversible capacities of 651 and 592 mA h g^(−1) are measured for the other two different current densities of 500 and 700 mA g^(−1),respectively,after 120 cycles,demonstrating the high stability of the anode.This unique morphology appears to contribute to the significantly high rate performance,as observed from the retained reversible capacity of 155 mA h g^(−1) at a very high current density of 10000 mA g^(−1),which is maintained for the next two subsequent sequences with a notable recovered capacity of 700 mA h g^(−1) for an intermediate current density of 400 mA g^(−1) after 175 cycles.
基金the National Natural Science Foundation of China(Grant No.61874048,11574110,11874348,U1831113)the Project of Science and Technology Plan of Jilin Province(Grant No.20180414020GH)the Project of Jilin Provincial Development and Reform Commission(2018C040-2)for the support of this work.
文摘In this paper,CuO–CdS composites were synthesized by a facile two-step solvothermal method.The composite materials were characterized by a series of systematical measures,such as X-ray diffraction,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,scanning electron microscopy and transmission electron microscopy.Through detailed experiments,it was observed that the shape of the as-prepared materials could be tailored by varying the CuO content in composites.The experimental results manifested that CdS decorated with 0.05 at%CuO presents superior performance including response/recovery speed,detection limit,optimum operating temperature,and sensitivity in comparison with pure CdS.The possible mechanisms of enhanced sensing properties were discussed in detail.At the interface of the two different material surfaces,the capacity of surface-adsorbed oxygen was elevated,which can be attributed to the formation of the p–n heterojunction between CdS and CuO.In conclusion,the functionalization of CuO with CdS may be a promising method to enhance gassensing properties.
基金financially supported by the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen(no.JCYJ20170412153139454)the National Natural Science Foundation of China(no.21875097)+1 种基金Natural Science Foundation of Guangdong Province(no.2018A030313725 and 2018B030322001)the Professorial and Doctoral Scientific Research Foundation of Huizhou University(no.2020JB025).
文摘Lithium-rich layered oxide cathodes have an advantage of high energy density.However,continuous capacity fading and voltage hysteresis have largely restricted their practical application.In this work,we investigated in depth the voltage-fading mechanism of Li-rich materials by in situ Raman spectroscopy,X-ray absorption near edge structure(XANES)spectroscopy,andhigh-resolution transmission electron microscopy(HRTEM).
基金supported by the National Science Council and the Ministry of Education of Taiwan(Republic of China).
文摘Redox activity of copper species immobilized poly(o-aminophenol)/multi-walled carbon nanotube(Cu@MWCNT-POAP)composite is reported for direct electrocatalysis towards detection of H_(2)O_(2).The Cu@MWCNT-POAP composite was prepared by a single step in situ electrochemical method.The as-prepared Cu@MWCNT-POAP composites were characterized by field emission scanning electron microscopy,Fourier transform infrared spectroscopy,Raman spectroscopy,X-ray diffraction,and electrochemical impedance spectroscopy.Cyclic voltammetry(CV)studies highlighted the good redox behavior of the Cu@MWCNT-POAP composite resulting from direct electron transfer behavior of the copper redox couple(Cu^(2+)/Cu^(+)).The Cu@MWCNT-POAP composite displayed superior electrocatalytic activity and high performance towards detection of H_(2)O_(2)because of its large surface area and homogenous immobilization of Cu species on the MWCNT-POAP composite.The analytical sensitivity and detection limit of the sensor were 831μA mM^(-1)cm^(-2)and 30 nM,respectively.In addition,bio-catalytic activity of the sensor was evaluated using the Michaelis-Menten constant.The Cu@MWCNT-POAP composite showed excellent stability and reproducibility,and good recoveries for determination of H_(2)O_(2)in milk,bleach cream,and contact lens solutions.
