Exploring novel versatile electrode materials with outstanding electrochemical performance is the key to the development of advanced energy conversion and storage devices.In this work,we aim to construct new-fangled o...Exploring novel versatile electrode materials with outstanding electrochemical performance is the key to the development of advanced energy conversion and storage devices.In this work,we aim to construct new-fangled one-dimensional(1D)quasi-layered patronite vanadium tetrasulfide(VS_(4))nanostructures by using different sulfur sources,namely thiourea,thioacetamide,and L-cysteine through an ethyleneaminetetraacetic-acid(EDTA)-mediated solvothermal process.The as-prepared VS4exhibits several unique morphologies such as urchin,fluffy nanoflower,and polyhedron with appropriate surface areas.Among the prepared nanostructures,the VS_(4)-1@NF nanostructure exhibited excellent electrochemical properties in 6 M KOH solution,and we explored its redox electrochemistry in detail.The asprepared VS_(4)-1@NF electrode exhibited battery-type redox characteristics with the highest capacity of280 C g^(-1)in a three-electrode assembly.Moreover,it offered a capacity of 123 F g^(-1)in a hybrid twoelectrode set-up at 1 A g^(-1)with the highest specific energy and specific power of 38.5 W h kg^(-1)and750 W kg^(-1),respectively.Furthermore,to ensure the practical applicability and real-world performance of the prepared hybrid AC@NF//VS_(4)-1@NF cell,we performed a cycling stability test with more than 5,000galvanostatic charge–discharge cycles at 2 A g^(-1),and the cell retained around 84.7%of its capacitance even after 5,000 cycles with a CE of 96.1%.展开更多
The removal of emerging micropollutants in the aquatic environment remains a global challenge.Conventional routes are often chemically,energetically,and operationally intensive,which decreases their sustainability dur...The removal of emerging micropollutants in the aquatic environment remains a global challenge.Conventional routes are often chemically,energetically,and operationally intensive,which decreases their sustainability during applications.Herein,we develop an advanced chemical-free strategy for micropollutants decontamination that is solely based on sequential electrochemistry involving ubiquitous sulfate anions in natural and engineered waters.This can be achieved via a chain reaction initiated by electrocatalytic anodic sulfate(SO_(4)^(2-))oxidation to produce persulfate(S_(2)O_(8)^(2-))and followed by a cathodic persulfate reduction to produce sulfate radicals(SO_(4)^(·-)).These SO_(4)^(·-)are powerful reactive species that enable the unselective degradation of micropollutants and yield SO_(4)^(2-)again in the treated water.The proposed flow-through electrochemical system achieves the efficient degradation(100.0%)and total organic carbon removal(65.0%)of aniline under optimized conditions with a single-pass mode.We also reveal the effectiveness of the proposed system for the degradation of a wide array of emerging micropollutants over a broad pH range and in complex matrices.This work provides the first proof-ofconcept demonstration using ubiquitous sulfate for micropollutants decontamination,making water purification more sustainable and more economical.展开更多
A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemi...A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.展开更多
The development of highly safe and low-cost aqueous batteries is of great significance in the background of carbon neutrality.However,the practical deployment of aqueous batteries has been plagued due to their relativ...The development of highly safe and low-cost aqueous batteries is of great significance in the background of carbon neutrality.However,the practical deployment of aqueous batteries has been plagued due to their relatively low capacity and poor cycling stability.Herein,we propose unique conversion electrochemistry of copper selenides for robust and energetic aqueous charge storage.In situ X-ray diffraction and operando Raman techniques reveal a reversible transformation from CuSe to Cu_(2)Se through the intermediates of Cu_(3)Se_(2) and Cu_(1.8)Se.Such a conversion process activates the redox carrier of Cu^(2+)ion and delivers a remarkable rate capability of 285 mAh g^(-1) at 20 A g^(-1) and electrochemical durability up to 30,000 cycles.Furthermore,Cu^(2+)and H+coinsertion chemistry is proposed to facilitate the conversion process.As a proof-of-concept,a hybrid aqueous pouch cell coupling CuSe//Zn is capable of affording maximum energy and power densities of 190 Wh kg^(-1) and 1366W kg^(-1),respectively.展开更多
Chloropcroxidase (CPO) was immobilized by konjac glucomannan (KGM) on the 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4]/Nafion modified glassy carbon eloctrode. The electrochemical behaviors of the im...Chloropcroxidase (CPO) was immobilized by konjac glucomannan (KGM) on the 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4]/Nafion modified glassy carbon eloctrode. The electrochemical behaviors of the immobilized CPO were investigated by cyclic voltammetry. The results showed that CPO was successfully immobilized on the GCE and underwent fast direct electron transfer reactions with the formal potential at -0.3 V vs. SCE. The modified electrode showed a good catalytic activity for elcctrocatalytical reduction of O2 and H2O2.展开更多
For designing batteries with high-rate and long-life, electronic/ionic transport and reaction must be unified for metal oxide electrodes. However, it remains challenging for effectively integrating the whole substrate...For designing batteries with high-rate and long-life, electronic/ionic transport and reaction must be unified for metal oxide electrodes. However, it remains challenging for effectively integrating the whole substrate/active materials/electrolyte interfaces. Herein by taking Li ion battery as example, we propose a semiconductor-electrochemistry model by which a general but novel insight has been gained into interfacial effect in batteries. Different from those traditional viewpoints, this derived model lies across from physics to electrochemistry. A reaction driving force can be expressed in terms of Fermi energy change,based on the tradeoff between electronic and ionic concentration at the reaction interfacial region. Therefore, at thermodynamic-controlled interface I of substrate/electrode, increasing contact areas can afford higher activity for active materials. Whereas at kinetically-governed interface II of electrode/electrolyte or inside active materials, it is crucial to guarantee high-reaction Li ionic concentration, with which some sufficient reaction degrees can reach.展开更多
Layered two-dimensional(2 D)materials have received tremendous attention due to their unique physical and chemical properties when downsized to single or few layers.Several types of layered materials,especially transi...Layered two-dimensional(2 D)materials have received tremendous attention due to their unique physical and chemical properties when downsized to single or few layers.Several types of layered materials,especially transition metal dichalcogenides(TMDs)have been demonstrated to be good electrode materials due to their interesting physical and chemical properties.Apart from TMDs,post-transition metal chalcogenides(PTMCs)recently have emerged as a family of important semiconducting materials for electrochemical studies.PTMCs are layered materials which are composed of post-transition metals raging from main group IIIA to group VA(Ga,In,Ge,Sn,Sb and Bi)and group VI chalcogen atoms(S,selenium(Se)and tellurium(Te)).Although a large number of literatures have reviewed the electrochemical and electrocatalytic applications of TMDs,less attention has been focused on PTMCs.In this review,we focus our attention on PTMCs with the aim to provide a summary to describe their fundamental electrochemical properties and electrocatalytic activity towards hydrogen evolution reaction(HER).The characteristic chemical compositions and crystal structures of PTMCs are firstly discussed,which are different from TMDs.Then,inherent electrochemistry of PTMCs is discussed to unveil the well-defined redox behaviors of PTMCs,which could potentially affect their efficiency when applied as electrode materials.Following,we focus our attention on electrocatalytic activity of PTMCs towards HER including novel synthetic strategies developed for the optimization of their HER activity.This review ends with the perspectives for the future research direction in the field of PTMC based electrocatalysts.展开更多
In the past decade, the aprotic lithium-oxygen(Li-O_2) battery has generated a great deal of interest because theoretically it can store more energy than today's lithium-ion batteries. Although considerable resear...In the past decade, the aprotic lithium-oxygen(Li-O_2) battery has generated a great deal of interest because theoretically it can store more energy than today's lithium-ion batteries. Although considerable research efforts have been devoted to the R&D of this potentially disruptive technology, many scientific and engineering obstacles still remain to be addressed before a practical device could be realized. In this review, we summarize recent advances in the fundamental understanding of the O_2 electrochemistry in Li-O_2 batteries, including the O_2 reduction to Li_2O_2 on discharge and the reverse Li_2 O_2 oxidation on recharge and factors that exert strong influences on the redox of O_2/Li_2O_2. In addition,challenges and perspectives are also provided for the future study of Li—O_2 batteries.展开更多
Techniques are developed for studying the mechanism of localized corrosion and protectivemeasures against such corrosion are suggested.The pH values and composition of the occluded sol-ution at different propagation s...Techniques are developed for studying the mechanism of localized corrosion and protectivemeasures against such corrosion are suggested.The pH values and composition of the occluded sol-ution at different propagation stages are determined.Measurements of the critical pH value and cor-rosion rate inside the occluded cells are conducted.Potential-pH diagrams depicting kinetic andthermodynamic behaviors of occluded cell corrosion are being established.The mechanism of inhibi-tion of pitting and stress corrosion cracking have also been investigated.展开更多
Stable adsorption and direct electrochemistry of glucose oxidase (COx) occurred on nitric acid (HNO3)-treated multi-walled carbon nanotubcs (MWNTs) instead of as-received MWNTs, demonstrating the critical roles ...Stable adsorption and direct electrochemistry of glucose oxidase (COx) occurred on nitric acid (HNO3)-treated multi-walled carbon nanotubcs (MWNTs) instead of as-received MWNTs, demonstrating the critical roles of oxygen-containing groups in stable adsorption and direct electrochemistry of GOx on carbon nanotubcs (CNTs).展开更多
The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E^0) of Hb was -0....The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E^0) of Hb was -0.105 V versus SCE, the electron transfer rate constant was 4.66 s-1. E^0' of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of-49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0× 10^-6 to 2.2× 10^-3 mol/L. The detection limit was 2.0× 10^-7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant(Km^app) was 2.95 mmol/L.展开更多
Room temperature ionic liquid (RTILs) [BMIM]PF6 was used as a new kind of binder to construct a chemical modified carbon paste electrode (CPE) and the direct electrochemistry of hemoglobin (Hb), which was immobi...Room temperature ionic liquid (RTILs) [BMIM]PF6 was used as a new kind of binder to construct a chemical modified carbon paste electrode (CPE) and the direct electrochemistry of hemoglobin (Hb), which was immobilized on the surface of RTIL/CPE with the film of sodium alginate hydrogel, was studied by cyclic voltammetry. The presence of RTILs improved the direct electron transfer of Hb and a pair of well-defined quasi-revesible redox peaks appeared in pH 7.0 B-R buffer solution. The cathodic and anodic peak potentials were located at -0.383 V and -0.305 V with the formal potential (E^0) at -0.344 V (vs. SCE). In addition the immobilized Hb showed good electrocatalytic activity to the reduction of H2O2.展开更多
The difference in the electrochemical behavior of hydroquinone and pyrocatechol at platinum and gold surfaces was analyzed using voltammetry and attenuated total reflection Fourier transform infrared spectroscopy. The...The difference in the electrochemical behavior of hydroquinone and pyrocatechol at platinum and gold surfaces was analyzed using voltammetry and attenuated total reflection Fourier transform infrared spectroscopy. The results show that the hydroquinone derivatives are adsorbed on a gold surface with vertical orientation, which makes the electron transfer between the bulk species and the electrode surface easier than that in the case of flat adsorption of hydroquinone derivatives that occurs at a platinum electrode. The formation of the vertical conformation and the rapid process of electron transfer were also confirmed by quantum chemistry calculations. In addition, the pre-adsorbed iodine on the electrodes played a key role on the adsorbed configuration and electron transfer of redox species.展开更多
The recent development on flotation electrochemistry of sulphide minerals at Central South University of Technology is briefly summarized. General behavior of natural floatability, self and sulphur induced, and collec...The recent development on flotation electrochemistry of sulphide minerals at Central South University of Technology is briefly summarized. General behavior of natural floatability, self and sulphur induced, and collector induced floatability of sulphide minerals are described. The mechanism is discussed based on Eh pH diagrams, voltammograms, energy band theory and molecular orbital theory.展开更多
This paper described the first example of polyamidoamine dendrimers ester(PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as aplasticizer. The polymer films are solid and sticky. Bac...This paper described the first example of polyamidoamine dendrimers ester(PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as aplasticizer. The polymer films are solid and sticky. Background cyclic voltammetry (CV) shows apotential window between +0.7 and -0.7 V vs. Ag/AgCl. The voltammetry of ferrocene and7,7,8,8-tetracyanoquinodimethane (TCNQ) indicates that diffusion coefficients are in the range of10^(-8) -10^(-9) cm^2/s. Ionic conductivities are approximately 10^(-6) S/cm. Similar films usingdimethyl sulfoxide (DMSO) as a plasticizer instead of MPEG-400 have demonstrated ionicconductivities of 10^(-4) S/cm and reversible voltammetry. However, UV spectropho-tometry shows that70% of the DMSO is lost under vacuum, indicating the difficulty in quantifying the DMSO contentwhen exposed to vacuum.展开更多
Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film e...Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film electrodes showed stable and reversible cyclic voltammetric responses in buffers and can catalyze the reduction of id (TCA).展开更多
Novel porous Mn2O3 with good crystallinity was synthesized via hard-template method. Hb-Mn2O3 na-nocomposite was prepared and used for biosensor construction. The Hb-Mn2O3-Nafion modified electrode shows fast direct e...Novel porous Mn2O3 with good crystallinity was synthesized via hard-template method. Hb-Mn2O3 na-nocomposite was prepared and used for biosensor construction. The Hb-Mn2O3-Nafion modified electrode shows fast direct electron transfer and displays good electrocatalytic response to the reduction of H2O2. The response time is less than 5 s, the sensitivity is as high as 493 μA·L·mmol-1·cm-2 in a linear range of 1-100 μmol/L, and the detection limit is 0.16 μmol/L. This modified electrode also shows good stability and reproducibility. This indicates that the porous Mn2O3 provides a good matrix for enzyme immobilization and biosensor construction.展开更多
基金supported by the Research Program of Dongguk University in 2022(No.S-2022-G0001-00016)。
文摘Exploring novel versatile electrode materials with outstanding electrochemical performance is the key to the development of advanced energy conversion and storage devices.In this work,we aim to construct new-fangled one-dimensional(1D)quasi-layered patronite vanadium tetrasulfide(VS_(4))nanostructures by using different sulfur sources,namely thiourea,thioacetamide,and L-cysteine through an ethyleneaminetetraacetic-acid(EDTA)-mediated solvothermal process.The as-prepared VS4exhibits several unique morphologies such as urchin,fluffy nanoflower,and polyhedron with appropriate surface areas.Among the prepared nanostructures,the VS_(4)-1@NF nanostructure exhibited excellent electrochemical properties in 6 M KOH solution,and we explored its redox electrochemistry in detail.The asprepared VS_(4)-1@NF electrode exhibited battery-type redox characteristics with the highest capacity of280 C g^(-1)in a three-electrode assembly.Moreover,it offered a capacity of 123 F g^(-1)in a hybrid twoelectrode set-up at 1 A g^(-1)with the highest specific energy and specific power of 38.5 W h kg^(-1)and750 W kg^(-1),respectively.Furthermore,to ensure the practical applicability and real-world performance of the prepared hybrid AC@NF//VS_(4)-1@NF cell,we performed a cycling stability test with more than 5,000galvanostatic charge–discharge cycles at 2 A g^(-1),and the cell retained around 84.7%of its capacitance even after 5,000 cycles with a CE of 96.1%.
基金supported by the National Natural Science Foundation of China(52170068 and U21A20161)the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(QAK202108)。
文摘The removal of emerging micropollutants in the aquatic environment remains a global challenge.Conventional routes are often chemically,energetically,and operationally intensive,which decreases their sustainability during applications.Herein,we develop an advanced chemical-free strategy for micropollutants decontamination that is solely based on sequential electrochemistry involving ubiquitous sulfate anions in natural and engineered waters.This can be achieved via a chain reaction initiated by electrocatalytic anodic sulfate(SO_(4)^(2-))oxidation to produce persulfate(S_(2)O_(8)^(2-))and followed by a cathodic persulfate reduction to produce sulfate radicals(SO_(4)^(·-)).These SO_(4)^(·-)are powerful reactive species that enable the unselective degradation of micropollutants and yield SO_(4)^(2-)again in the treated water.The proposed flow-through electrochemical system achieves the efficient degradation(100.0%)and total organic carbon removal(65.0%)of aniline under optimized conditions with a single-pass mode.We also reveal the effectiveness of the proposed system for the degradation of a wide array of emerging micropollutants over a broad pH range and in complex matrices.This work provides the first proof-ofconcept demonstration using ubiquitous sulfate for micropollutants decontamination,making water purification more sustainable and more economical.
文摘A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.
基金Natural Science Foundation of Shanghai,Grant/Award Number:22ZR1403600Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20180002+1 种基金National Natural Science Foundation of China,Grant/Award Numbers:22109029,51772197,51872192,52025028,52172219Natural Science Foundation of the Jiangsu Higher Education Institutions of China,Grant/Award Number:19KJA170001。
文摘The development of highly safe and low-cost aqueous batteries is of great significance in the background of carbon neutrality.However,the practical deployment of aqueous batteries has been plagued due to their relatively low capacity and poor cycling stability.Herein,we propose unique conversion electrochemistry of copper selenides for robust and energetic aqueous charge storage.In situ X-ray diffraction and operando Raman techniques reveal a reversible transformation from CuSe to Cu_(2)Se through the intermediates of Cu_(3)Se_(2) and Cu_(1.8)Se.Such a conversion process activates the redox carrier of Cu^(2+)ion and delivers a remarkable rate capability of 285 mAh g^(-1) at 20 A g^(-1) and electrochemical durability up to 30,000 cycles.Furthermore,Cu^(2+)and H+coinsertion chemistry is proposed to facilitate the conversion process.As a proof-of-concept,a hybrid aqueous pouch cell coupling CuSe//Zn is capable of affording maximum energy and power densities of 190 Wh kg^(-1) and 1366W kg^(-1),respectively.
基金supported by grants from National Natural Science Foundation of China (No.20503016,20775049).
文摘Chloropcroxidase (CPO) was immobilized by konjac glucomannan (KGM) on the 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF4]/Nafion modified glassy carbon eloctrode. The electrochemical behaviors of the immobilized CPO were investigated by cyclic voltammetry. The results showed that CPO was successfully immobilized on the GCE and underwent fast direct electron transfer reactions with the formal potential at -0.3 V vs. SCE. The modified electrode showed a good catalytic activity for elcctrocatalytical reduction of O2 and H2O2.
基金the National Natural Science Foundation of China(51872115)Program for the Development of Science and Technology of Jilin Province(20190201309JC)+5 种基金the Fundamental Research Funds for the Central Universities(Grant no.531107051230)The Open Project Program of Wuhan National Laboratory for Optoelectronicsthe Jilin Province/Jilin University co-Construction Project-Funds for New Materials(SXGJSF2017-3,Branch-2/440050316A36)Program for JLU Science and Technology Innovative Research Team(JLUSTIRT,2017TD-09)the Fundamental Research Funds for the Central Universities,JLU“Double-First Class”Discipline for Materials Science&Engineering。
文摘For designing batteries with high-rate and long-life, electronic/ionic transport and reaction must be unified for metal oxide electrodes. However, it remains challenging for effectively integrating the whole substrate/active materials/electrolyte interfaces. Herein by taking Li ion battery as example, we propose a semiconductor-electrochemistry model by which a general but novel insight has been gained into interfacial effect in batteries. Different from those traditional viewpoints, this derived model lies across from physics to electrochemistry. A reaction driving force can be expressed in terms of Fermi energy change,based on the tradeoff between electronic and ionic concentration at the reaction interfacial region. Therefore, at thermodynamic-controlled interface I of substrate/electrode, increasing contact areas can afford higher activity for active materials. Whereas at kinetically-governed interface II of electrode/electrolyte or inside active materials, it is crucial to guarantee high-reaction Li ionic concentration, with which some sufficient reaction degrees can reach.
基金financial support from the National Natural Science Foundation of China(Grant No.11774044)。
文摘Layered two-dimensional(2 D)materials have received tremendous attention due to their unique physical and chemical properties when downsized to single or few layers.Several types of layered materials,especially transition metal dichalcogenides(TMDs)have been demonstrated to be good electrode materials due to their interesting physical and chemical properties.Apart from TMDs,post-transition metal chalcogenides(PTMCs)recently have emerged as a family of important semiconducting materials for electrochemical studies.PTMCs are layered materials which are composed of post-transition metals raging from main group IIIA to group VA(Ga,In,Ge,Sn,Sb and Bi)and group VI chalcogen atoms(S,selenium(Se)and tellurium(Te)).Although a large number of literatures have reviewed the electrochemical and electrocatalytic applications of TMDs,less attention has been focused on PTMCs.In this review,we focus our attention on PTMCs with the aim to provide a summary to describe their fundamental electrochemical properties and electrocatalytic activity towards hydrogen evolution reaction(HER).The characteristic chemical compositions and crystal structures of PTMCs are firstly discussed,which are different from TMDs.Then,inherent electrochemistry of PTMCs is discussed to unveil the well-defined redox behaviors of PTMCs,which could potentially affect their efficiency when applied as electrode materials.Following,we focus our attention on electrocatalytic activity of PTMCs towards HER including novel synthetic strategies developed for the optimization of their HER activity.This review ends with the perspectives for the future research direction in the field of PTMC based electrocatalysts.
基金supported by the National Foundation of China (Grant No. 91545129, 21575135 and 21605136)the "Strategic Priority Research Program" of the CAS (Grant No. XDA09010401)+1 种基金the National Key R&D Program of China (Grant No. 2016YBF0100100)the Science and Technology Development Program of the Jilin Province (Grant No. 20150623002TC and 20160414034GH)
文摘In the past decade, the aprotic lithium-oxygen(Li-O_2) battery has generated a great deal of interest because theoretically it can store more energy than today's lithium-ion batteries. Although considerable research efforts have been devoted to the R&D of this potentially disruptive technology, many scientific and engineering obstacles still remain to be addressed before a practical device could be realized. In this review, we summarize recent advances in the fundamental understanding of the O_2 electrochemistry in Li-O_2 batteries, including the O_2 reduction to Li_2O_2 on discharge and the reverse Li_2 O_2 oxidation on recharge and factors that exert strong influences on the redox of O_2/Li_2O_2. In addition,challenges and perspectives are also provided for the future study of Li—O_2 batteries.
文摘Techniques are developed for studying the mechanism of localized corrosion and protectivemeasures against such corrosion are suggested.The pH values and composition of the occluded sol-ution at different propagation stages are determined.Measurements of the critical pH value and cor-rosion rate inside the occluded cells are conducted.Potential-pH diagrams depicting kinetic andthermodynamic behaviors of occluded cell corrosion are being established.The mechanism of inhibi-tion of pitting and stress corrosion cracking have also been investigated.
基金This research is supported by the National Natural Science Foundation of China(Nos.30370397 and 60571042).
文摘Stable adsorption and direct electrochemistry of glucose oxidase (COx) occurred on nitric acid (HNO3)-treated multi-walled carbon nanotubcs (MWNTs) instead of as-received MWNTs, demonstrating the critical roles of oxygen-containing groups in stable adsorption and direct electrochemistry of GOx on carbon nanotubcs (CNTs).
基金Supported by the National Natural Science Foundation of China(No.20605009)
文摘The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E^0) of Hb was -0.105 V versus SCE, the electron transfer rate constant was 4.66 s-1. E^0' of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of-49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0× 10^-6 to 2.2× 10^-3 mol/L. The detection limit was 2.0× 10^-7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant(Km^app) was 2.95 mmol/L.
基金supported by the National Natural.Science Foundation of China(No.20405008,20635020).
文摘Room temperature ionic liquid (RTILs) [BMIM]PF6 was used as a new kind of binder to construct a chemical modified carbon paste electrode (CPE) and the direct electrochemistry of hemoglobin (Hb), which was immobilized on the surface of RTIL/CPE with the film of sodium alginate hydrogel, was studied by cyclic voltammetry. The presence of RTILs improved the direct electron transfer of Hb and a pair of well-defined quasi-revesible redox peaks appeared in pH 7.0 B-R buffer solution. The cathodic and anodic peak potentials were located at -0.383 V and -0.305 V with the formal potential (E^0) at -0.344 V (vs. SCE). In addition the immobilized Hb showed good electrocatalytic activity to the reduction of H2O2.
基金Supported by the National Natural Science Foundation of China(No. 20475053) and Department of Science and Technology ofJilin Province(No.20050102)
文摘The difference in the electrochemical behavior of hydroquinone and pyrocatechol at platinum and gold surfaces was analyzed using voltammetry and attenuated total reflection Fourier transform infrared spectroscopy. The results show that the hydroquinone derivatives are adsorbed on a gold surface with vertical orientation, which makes the electron transfer between the bulk species and the electrode surface easier than that in the case of flat adsorption of hydroquinone derivatives that occurs at a platinum electrode. The formation of the vertical conformation and the rapid process of electron transfer were also confirmed by quantum chemistry calculations. In addition, the pre-adsorbed iodine on the electrodes played a key role on the adsorbed configuration and electron transfer of redox species.
文摘The recent development on flotation electrochemistry of sulphide minerals at Central South University of Technology is briefly summarized. General behavior of natural floatability, self and sulphur induced, and collector induced floatability of sulphide minerals are described. The mechanism is discussed based on Eh pH diagrams, voltammograms, energy band theory and molecular orbital theory.
基金This work was financially supported by the National Natural Science Foundation of China (No. 29875018) the Natural Science Foundation of Gansu Province (No. ZS991-A25-008-Z)the Doctorate Foundation of Northwestern Politech-nical University (No. CX200
文摘This paper described the first example of polyamidoamine dendrimers ester(PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as aplasticizer. The polymer films are solid and sticky. Background cyclic voltammetry (CV) shows apotential window between +0.7 and -0.7 V vs. Ag/AgCl. The voltammetry of ferrocene and7,7,8,8-tetracyanoquinodimethane (TCNQ) indicates that diffusion coefficients are in the range of10^(-8) -10^(-9) cm^2/s. Ionic conductivities are approximately 10^(-6) S/cm. Similar films usingdimethyl sulfoxide (DMSO) as a plasticizer instead of MPEG-400 have demonstrated ionicconductivities of 10^(-4) S/cm and reversible voltammetry. However, UV spectropho-tometry shows that70% of the DMSO is lost under vacuum, indicating the difficulty in quantifying the DMSO contentwhen exposed to vacuum.
文摘Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film electrodes showed stable and reversible cyclic voltammetric responses in buffers and can catalyze the reduction of id (TCA).
基金Supported by the National Basic Research Program of China(No.2011CB935700)the National Natural Science Foundation of China(No.U0734002)
文摘Novel porous Mn2O3 with good crystallinity was synthesized via hard-template method. Hb-Mn2O3 na-nocomposite was prepared and used for biosensor construction. The Hb-Mn2O3-Nafion modified electrode shows fast direct electron transfer and displays good electrocatalytic response to the reduction of H2O2. The response time is less than 5 s, the sensitivity is as high as 493 μA·L·mmol-1·cm-2 in a linear range of 1-100 μmol/L, and the detection limit is 0.16 μmol/L. This modified electrode also shows good stability and reproducibility. This indicates that the porous Mn2O3 provides a good matrix for enzyme immobilization and biosensor construction.