SnO_(2)is regarded as a promising lithium storage material due to the advantage of sequential conversion-alloying reaction mechanism.Unfortunately,large volume expansion and undesirable reaction reversibility are iden...SnO_(2)is regarded as a promising lithium storage material due to the advantage of sequential conversion-alloying reaction mechanism.Unfortunately,large volume expansion and undesirable reaction reversibility are identified as two fatal drawbacks.Herein,SnO_(2)nanoparticles encapsulated in graphene oxide-coated porous biochar skeleton(SnO_(2)/PB@GO)are skillfully constructed via an efficient one-step hydrothermal process to be employed as composite anode materials,in which the PB skeleton extracted from waste tea-seed shells possesses enough space to buffer drastic volume variation and the GO coating acts as robust physical matrix to prevent structural degradation.Moreover,double-carbon components successfully anchor SnO_(2)nanoparticles to promote contact and reaction between Sn and Li_(2)O to guarantee high reaction reversibility and structural integration of SnO_(2)/PB@GO electrode.As expected,SnO_(2)/PB@GO-based cell achieves high reversible specific capacity of 783.5 mAh·g^(-1)after 100 cycles at0.1 A.g^(-1)and delivers desirable cycling stability with capacity retention ratio of 81.62%after 300 cycles at1.0 A.g^(-1).Therefore,this work may provide new perspectives on the modification of conversion or alloying typeanodes for lithium-ion batteries and present a feasible strategy to take full advantage of the waste biomass.展开更多
The objective of this work was to study the effect of different rolling technologies on the properties of Pb-0.06wt%Ca-1.2wt%Sn anodes during copper electrowinning and to determine the relationship between the propert...The objective of this work was to study the effect of different rolling technologies on the properties of Pb-0.06wt%Ca-1.2wt%Sn anodes during copper electrowinning and to determine the relationship between the properties of the anodes and rolling techniques during copper electrowinning. The anode process was investigated via anodic polarization curves, cyclic voltammetry curves, electrochemical impedance spectra, and corrosion tests. The microscopic morphology and phase composition of the anodic oxide layers were observed by scanning electron microscopy and X-ray diffraction, respectively. Observable variations in the electrocatalytic activity and reaction kinetics of anodes during electrowinning indicated that the electrochemical behavior of the anodes was strongly affected by the rolling technology. An increase in the rolling number tended to decrease the oxygen evolution overpotential and the corrosion rate of the anodes. These trends are contrary to that of the apparent exchange current density. Furthermore, the intensities of diffraction peaks associated with PbO, PbOx, and α-PbO2 tended to increase with increasing rolling number. In addition, the rolled anodes exhibited a more uniform microstructure. Compared with one-way rolled anodes, the eight-time cross rolled anodes exhibited better electrocatalytic activity and improved corrosion resistance.展开更多
Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow Sn O2@C nanoparticles（NPs） with ...Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow Sn O2@C nanoparticles（NPs） with a mean size of 50 nm have been synthesized in large-scale via a facile hydrothermal approach.The morphology and composition of as-obtained products were studied by various characterized techniques. As an anode material for lithium ion batteries（LIBs）, the as-prepared hollow Sn O2@C NPs exhibit significant improvement in cycle performances. The discharge capacity of lithium battery is as high as 370 m Ah g 1, and the current density is 3910 m A g 1（5 C） after 573 cycles. Furthermore, the capacity recovers up to 1100 m Ah g 1at the rate performances in which the current density is recovered to 156.4 m A g 1（0.2 C）. Undoubtedly, sub-100 nm Sn O2@C NPs provide significant improvement to the electrochemical performance of LIBs as superior-anode nanomaterials, and this carbon coating strategy can pave the way for developing high-performance LIBs.展开更多
A simple, cost effective and rapid electrochemical method has been developed for the determination of micro level ortho nitrobenzaldehyde（ONB） based on outstanding properties of modified aluminum electrode tin nanor...A simple, cost effective and rapid electrochemical method has been developed for the determination of micro level ortho nitrobenzaldehyde（ONB） based on outstanding properties of modified aluminum electrode tin nanorods/anodic aluminum oxide/aluminum（SnNR/AAO/Al） for the first time. The SnNR/AAO/Al electrode was fabricated by a second step anodization, followed by electrodeposition and its electrochemical behavior was investigated in detail. The cyclic voltammetry results indicated that the SnNR/AAO/Al electrode exhibited efficient electrocatalytic activity toward reduction of ONB in the acidic solution. It provides an appreciable improvement of reduction peak for ONB at-0.721 V.Furthermore, various kinetic parameters such as transfer electron number, transfer proton number and standard heterogeneous rate constant were calculated from the scan rates.The electrocatalytic behavior was further exploited as a sensitive detection scheme for the ONB determination by differential pulse voltammetry. Under the optimized conditions, the concentration range and detection limit are 0.1-100 μmol/L and 0.05 μmol/L, respectively,for ONB. The analytical performance of this modified sensor has been evaluated for detection of real sample such as river water and recovery of ONB was achieved all-out up to102.3% under standard addition method.展开更多
Objective: The aim of this experiment is to study the effect of three methods of surface modification on the corrosion resistance of commercial pure Titanium when used in oral environment for half a year.Method:48 spe...Objective: The aim of this experiment is to study the effect of three methods of surface modification on the corrosion resistance of commercial pure Titanium when used in oral environment for half a year.Method:48 specimens of pure titanium were made and divided into four groups randomly, one group was selected randomly as Group I (control group), the other three groups were treated by three methods of surface modification individually, GroupⅡ:heating oxidation in air(400℃,30min.), GroupⅢ:anodization (45 volts, 10 min.),GroupⅣ:TiN coating(firing temperature 200℃ , total coating time 62min.). Six edentulous volunteers with healthy oral mucosa participated in the in vivo study. One testing piece from each group was selected and fixed in the polished surface of upper complete dentures. Dynamic polarization curves were traced with electrochemical method after the specimens were placed either in oral cavity or in air for 6 months. Results: After all specimens were used, Ecorr altered in every group , Ecorr from high to low were in turn: TiN coating group>heating oxidation group> anodization group>control group, no obvious passive potential Ep and Ip was found in control group. Heating oxidation in air exhibited similar Ep to anodization, but Ip was remarkably lower than that of anodization; TiN coating showed obviously different polarization curves compared with heating-oxidation group and anodization group, Ecorr was positive, and no Ep and Ip was found. Conclusion: Under present experimental condition, all the three treatment methods could enhance corrosion resistance of pure titanium in oral environment, heating oxidation in air exhibited better resistance to corrode than anodization, TiN coating possessed the most excellent corrosion resistance, even after exposed in oral condition for 6 months, there was little change of corrosion resistance. Therefore TiN coating could be adopted to improve corrosion resistance of pure titanium in oral environment.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52274292 and 51874046)the Outstanding Youth Foundation of Hubei Province(No.2020CFA090)+1 种基金the Project of Scientific Research of Jingzhou(No.2023EC37)the Young Top-notch Talent Cultivation Program of Hubei Province
文摘SnO_(2)is regarded as a promising lithium storage material due to the advantage of sequential conversion-alloying reaction mechanism.Unfortunately,large volume expansion and undesirable reaction reversibility are identified as two fatal drawbacks.Herein,SnO_(2)nanoparticles encapsulated in graphene oxide-coated porous biochar skeleton(SnO_(2)/PB@GO)are skillfully constructed via an efficient one-step hydrothermal process to be employed as composite anode materials,in which the PB skeleton extracted from waste tea-seed shells possesses enough space to buffer drastic volume variation and the GO coating acts as robust physical matrix to prevent structural degradation.Moreover,double-carbon components successfully anchor SnO_(2)nanoparticles to promote contact and reaction between Sn and Li_(2)O to guarantee high reaction reversibility and structural integration of SnO_(2)/PB@GO electrode.As expected,SnO_(2)/PB@GO-based cell achieves high reversible specific capacity of 783.5 mAh·g^(-1)after 100 cycles at0.1 A.g^(-1)and delivers desirable cycling stability with capacity retention ratio of 81.62%after 300 cycles at1.0 A.g^(-1).Therefore,this work may provide new perspectives on the modification of conversion or alloying typeanodes for lithium-ion batteries and present a feasible strategy to take full advantage of the waste biomass.
基金financial support of the National Natural Science Foundation of China (No.51004056)the Applied Basic Research Foundation of Yunnan Province (No. 2010ZC052)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 20125314110011)
文摘The objective of this work was to study the effect of different rolling technologies on the properties of Pb-0.06wt%Ca-1.2wt%Sn anodes during copper electrowinning and to determine the relationship between the properties of the anodes and rolling techniques during copper electrowinning. The anode process was investigated via anodic polarization curves, cyclic voltammetry curves, electrochemical impedance spectra, and corrosion tests. The microscopic morphology and phase composition of the anodic oxide layers were observed by scanning electron microscopy and X-ray diffraction, respectively. Observable variations in the electrocatalytic activity and reaction kinetics of anodes during electrowinning indicated that the electrochemical behavior of the anodes was strongly affected by the rolling technology. An increase in the rolling number tended to decrease the oxygen evolution overpotential and the corrosion rate of the anodes. These trends are contrary to that of the apparent exchange current density. Furthermore, the intensities of diffraction peaks associated with PbO, PbOx, and α-PbO2 tended to increase with increasing rolling number. In addition, the rolled anodes exhibited a more uniform microstructure. Compared with one-way rolled anodes, the eight-time cross rolled anodes exhibited better electrocatalytic activity and improved corrosion resistance.
基金the Program for the NSFC (Nos. 51302325, 51201115, 51471121)New Century Excellent Talents in University (No. NCET-12-0553)+4 种基金Program for Shenghua Overseas Talent (No. 1681-7607030005) from Central South UniversityHubei Provincial Natural Science Foundation (No. 2014CFB261)the partial financial support from the Open-End Fund for the Valuable and Precision Instruments of Central South University (No. CSUZC2014032)Fundamental Research Funds for the Central Universities (No. 2042015kf0184)Wuhan University
文摘Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow Sn O2@C nanoparticles（NPs） with a mean size of 50 nm have been synthesized in large-scale via a facile hydrothermal approach.The morphology and composition of as-obtained products were studied by various characterized techniques. As an anode material for lithium ion batteries（LIBs）, the as-prepared hollow Sn O2@C NPs exhibit significant improvement in cycle performances. The discharge capacity of lithium battery is as high as 370 m Ah g 1, and the current density is 3910 m A g 1（5 C） after 573 cycles. Furthermore, the capacity recovers up to 1100 m Ah g 1at the rate performances in which the current density is recovered to 156.4 m A g 1（0.2 C）. Undoubtedly, sub-100 nm Sn O2@C NPs provide significant improvement to the electrochemical performance of LIBs as superior-anode nanomaterials, and this carbon coating strategy can pave the way for developing high-performance LIBs.
基金CSIR (09/0810 (0021)/ 2012-EMR-I), Periyar University for providing fundUGC networking resource center for providing visiting fellowship
文摘A simple, cost effective and rapid electrochemical method has been developed for the determination of micro level ortho nitrobenzaldehyde（ONB） based on outstanding properties of modified aluminum electrode tin nanorods/anodic aluminum oxide/aluminum（SnNR/AAO/Al） for the first time. The SnNR/AAO/Al electrode was fabricated by a second step anodization, followed by electrodeposition and its electrochemical behavior was investigated in detail. The cyclic voltammetry results indicated that the SnNR/AAO/Al electrode exhibited efficient electrocatalytic activity toward reduction of ONB in the acidic solution. It provides an appreciable improvement of reduction peak for ONB at-0.721 V.Furthermore, various kinetic parameters such as transfer electron number, transfer proton number and standard heterogeneous rate constant were calculated from the scan rates.The electrocatalytic behavior was further exploited as a sensitive detection scheme for the ONB determination by differential pulse voltammetry. Under the optimized conditions, the concentration range and detection limit are 0.1-100 μmol/L and 0.05 μmol/L, respectively,for ONB. The analytical performance of this modified sensor has been evaluated for detection of real sample such as river water and recovery of ONB was achieved all-out up to102.3% under standard addition method.
基金This study was granted from the National Natural Science Foundation of China.Title of the grant-winning project:The Applied Basic Research on Surface Finishing for Titanium Dentures. January2002, serial number was :30171022.
文摘Objective: The aim of this experiment is to study the effect of three methods of surface modification on the corrosion resistance of commercial pure Titanium when used in oral environment for half a year.Method:48 specimens of pure titanium were made and divided into four groups randomly, one group was selected randomly as Group I (control group), the other three groups were treated by three methods of surface modification individually, GroupⅡ:heating oxidation in air(400℃,30min.), GroupⅢ:anodization (45 volts, 10 min.),GroupⅣ:TiN coating(firing temperature 200℃ , total coating time 62min.). Six edentulous volunteers with healthy oral mucosa participated in the in vivo study. One testing piece from each group was selected and fixed in the polished surface of upper complete dentures. Dynamic polarization curves were traced with electrochemical method after the specimens were placed either in oral cavity or in air for 6 months. Results: After all specimens were used, Ecorr altered in every group , Ecorr from high to low were in turn: TiN coating group>heating oxidation group> anodization group>control group, no obvious passive potential Ep and Ip was found in control group. Heating oxidation in air exhibited similar Ep to anodization, but Ip was remarkably lower than that of anodization; TiN coating showed obviously different polarization curves compared with heating-oxidation group and anodization group, Ecorr was positive, and no Ep and Ip was found. Conclusion: Under present experimental condition, all the three treatment methods could enhance corrosion resistance of pure titanium in oral environment, heating oxidation in air exhibited better resistance to corrode than anodization, TiN coating possessed the most excellent corrosion resistance, even after exposed in oral condition for 6 months, there was little change of corrosion resistance. Therefore TiN coating could be adopted to improve corrosion resistance of pure titanium in oral environment.
