An efficient interface modification is introduced to improve the performance of polymeric thin film transistors. This efficient interface modification is first achieved by 4-fluorothiophenol(4-FTP) self-assembled mo...An efficient interface modification is introduced to improve the performance of polymeric thin film transistors. This efficient interface modification is first achieved by 4-fluorothiophenol(4-FTP) self-assembled monolayers(SAM) to chemically treat the silver source–drain(S/D) contacts while the silicon oxide(SiO2) dielectric interface is further primed by either hexamethyldisilazane(HMDS) or octyltrichlorosilane(OTS-C8). Results show that contact resistance is the dominant factor that limits the field effect mobility of the PTDPPTFT4 transistors. With proper surface modification applied to both the dielectric surface and the bottom contacts, the field effect mobilities of the bottom-gate bottom-contact PTDPPTFT4 transistors were significantly improved from 0.15 cm^2·V^-1·s^-1 to 0.91 cm^2·V^-1·s^-1.展开更多
A novel electrode material based on chemically modified graphene (CMG) with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the ...A novel electrode material based on chemically modified graphene (CMG) with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the aminophenyl groups of p-phenylenediamine. Palladium nanoparticles with an average diameter of 4.2 nm are deposited on the CMG by a liquid-phase borohydride reduction. The electrocatalytic activity and stability of the Pd/CMG composite towards formic acid oxidation are found to be higher than those of reduced graphene oxide and commercial carbon materials such as Vulcan XC-72 supported Pd electrocatalysts.展开更多
The opticai properties of C,, chemicaiiy modified poiystyrene(C,, -PS copolymer) and the parent polystyrene (PS) films have been investigated.Addition of bulky C,, moiety, a special functional group, to the polystyren...The opticai properties of C,, chemicaiiy modified poiystyrene(C,, -PS copolymer) and the parent polystyrene (PS) films have been investigated.Addition of bulky C,, moiety, a special functional group, to the polystyrene by anovel organometallic reaction modified considerably the optical property of theparent polystyrene. The lattice periodicity of pure PS film is subject to someperturbation or distortion in varying degrees due to the covalent attachInent of bulkyC,, moiety to the polymer backbone. C,,-PS copolymer possesses a new energy ba-ndstructure with indirect forbidden band when compared with the parent PS.展开更多
Chemically modified clay(CMC) was used as an adsorbent for the removal of Astrazon Golden Yellow 7GL(AGY-7GL), which is a basic dye from wastewater. For this purpose, the chemically modified clay was first characteriz...Chemically modified clay(CMC) was used as an adsorbent for the removal of Astrazon Golden Yellow 7GL(AGY-7GL), which is a basic dye from wastewater. For this purpose, the chemically modified clay was first characterized by determining zero point of charge(p Hzpc), and using BET, SEM and FTIR. Then effects of operational parameters on adsorption of AGY-7GL were studied in a batch system. The effect of various parameters such as contact time(0-180 min), pH(2-8), temperature(293-323 K), CMC concentration(0.075-0.5 mg/L) and initial AGY-7GL concentration(75-250 mg/L) were investigated on the adsorption efficiency and capacity adsorption of CMC for the removal of AGY-7GL. Thermodynamic and kinetic parameters were calculated from the results of the adsorption experiment. The evaluation of kinetic models shows that this data best fits the pseudo-second-order model. It is determined that the adsorption equilibrium data works very well with the nonlinear Freundlich isotherm model. Thermodynamic parameters such as ?H^0(19.0 k J/mol), ?G^0(-28.8 k J/mol) and ?S^0(0.148 k J/mol) were also determined. According to the experimental results, it is concluded that CMC could be used as an alternative low cost potential adsorbent for the removal of AGY-7GL from wastewater.展开更多
The electrochemical behaviors of Eu3+ on Eastman AQ-29D/glassy carbon(GC) chemically modified electrode(CME) were studied. It was found that the reduction-oxidation process of Eu3+ is in a semi-infinite condition in 0...The electrochemical behaviors of Eu3+ on Eastman AQ-29D/glassy carbon(GC) chemically modified electrode(CME) were studied. It was found that the reduction-oxidation process of Eu3+ is in a semi-infinite condition in 0.1 mol/L NaCIO4 supporting electrolyte(pH 4.4). The calibration curve was linear over the range 1.0×10-7 to 1.0×105 mol/L of Eu3+.The charge transport apparent diffusion coefficient of Eu3+ in the polymer film was determined to be(3.2±1.1)×10-11cm2/s by chronocoulometry.展开更多
The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bar...The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...展开更多
A La^3+-Cu/Pt modified electrode was fabricated by electrodepositing process in CuS04 solution by adding a small amount of lanthium compound, and it was employed for direct current (DC) amperometric detection of sp...A La^3+-Cu/Pt modified electrode was fabricated by electrodepositing process in CuS04 solution by adding a small amount of lanthium compound, and it was employed for direct current (DC) amperometric detection of spectinomycin by anion-exchange chromatography. Without derivatization, this method can simultaneously determine the main component and impurities in spectinomycin pharmaceutical raw material. Ease of preparation, being applied in DC detection mode and good catalytic stability confirmed the interests of this modified electrode as amperometric sensor for the determination of spectinomycin.展开更多
A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition o...A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al and the peak potentials remain the same. The decreasing of Delta i(p) is linear with Al concentration in the range of 1 x 10(-8) similar to 1 x 10(-7) mol/L. The detection limit is 5 x 10(-9) mol/L and the relative standard deviation for 4 x 10(-8) mol/L Al is 2.9% (n=8). No serious interference was found. The determination of Al in water samples is reported.展开更多
The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a hi...The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity. The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_(pa)= 220 mV, E_(pc)=95 mV and the formal potential E^(o')= 157. 5 mV(vs. SCE) at 100 mV/s in the buffer solution of pH 7. 0. The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry. Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5. 0 × 10^(-6) to 5. 0 × 10^(-4) mol/L, and the detection limit is 1. 0 ×10^(-6) mol/L at S/N=3. Normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca. 30. 8: 1.展开更多
An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of ...An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of the modified electrode via formation of chemical complexes with calix[6]arene, and reduced at 1.40 V. During the following anodic potential sweep, reduced lead and cadmium were oxidized, and two well-defined striping peaks appeared at about ?0.60 V and ?0.84 V. Compared with a bare carbon paste electrode, the calix[6]arene modified CPE greatly improves the sensitivity of determining lead and cadmium. The stripping peak currents change linearly with the concentration of Pb2+ 3.0×10?8–8.0×10?6 mol·L?1 and with that of Cd2+ 6.0×10?8–1.0×10?5 mol ·L?1. The detection limits of Pb2+ and Cd2+ are found to be 8.0×10?9 mol·L?1 and 2.0×10?8 mol·L?1, respectively. The modified carbon paste electrode was applied to determine trace levels of lead and cadmium in water samples. Comparing with that of atomic absorption spectrometry, the results suggests that the calix[6]arene modified CPE has great potential for the practical sample analysis. Key words lead(II) - cadmium(II) - calix[6]arene - differential pulse stripping voltammetry - chemically modified electrode CLC number O 657.15 Foundation item: Supported by the National Natural Science Foundation of China (60171023)Biography: JI Xiao-bo (1980-), male, Master, research direction: electroanalytical chemistry.展开更多
s: A new method for the preparation of an organic-inorganic composite film of the heteropolyanion has been developed by modifying P(Mo2O7)6-7 to the indium tin oxide (ITO) electrode surface. The modified electrode dis...s: A new method for the preparation of an organic-inorganic composite film of the heteropolyanion has been developed by modifying P(Mo2O7)6-7 to the indium tin oxide (ITO) electrode surface. The modified electrode displayed a strong catalytic activity towards the reduction of IO3-. In the range of 1.0?0-6~5?0-4mol/L, the catalytic current was linear proportional to the IO3- concentration.展开更多
A novel fibroin modified electrode with ion recognition was reported. The membranewith isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. ThepH-responsive ion recognition of the modifie...A novel fibroin modified electrode with ion recognition was reported. The membranewith isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. ThepH-responsive ion recognition of the modified electrode was investigated by use of someneurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination.展开更多
It was newly found that the electrodes modified by applying ethanol solutions of Nationcontaining os(bpy)32+ onto the substrate electrode (the one-step method) show two pairs of stableredox peaks of Os(bpy)32+/3+ on c...It was newly found that the electrodes modified by applying ethanol solutions of Nationcontaining os(bpy)32+ onto the substrate electrode (the one-step method) show two pairs of stableredox peaks of Os(bpy)32+/3+ on cyclic voltammogram near 0.54V and 0.25V, respectively. Thesemoditied electrodes can effectively mediate and catalyze the first and second steps of nitritereduction in acidic media in the potential region 0-0.9V when the loading in the coating (X=F(Os2+) / F(SO3-)) and pH in solution are below 0. 17 and 4, respectively. When X is between 0.33and 0. 17. only the current peak near 0.54V appears regardless of solution pH and only the first stepof NO2 reduction is catalyzed. Thus the modified electrode provides a very useful flexibility thatone can control the reaction pathway and catalytic activity of nitrite reduction by simply changingthe concentration of the mediator in the coating.展开更多
Electrochemical behaviours of Europium-ferrocene derivative complex chemically modified electrodes were studied in the paper. Various factors which affect the voltammetry of the thin film modified electrodes, and the...Electrochemical behaviours of Europium-ferrocene derivative complex chemically modified electrodes were studied in the paper. Various factors which affect the voltammetry of the thin film modified electrodes, and the charge transport process of the thin film electrode were discussed. Size of the hydrated anion (counter ion), concentration of the electrolyte, swelling property of the film in the solvent and thickness of the film have significant effects on the voltammetry of the thin film electrode. Electrochemical behaviours of europium-ferrocene derivative compelx chemically modified electrode were studied in an aqueous solution. When scan ning between 0-0.8 V (vs. SCE), experimental results indicate that the chemically modified electrode has good stability and reproducibility. The apparent rate constant of electrode reaction is deteminedd to be 6.7×10-1 s-1.展开更多
Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite elec...Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite electrode has high specific surface area and high current density. The electrode modified by transition metallic ions has improved catalysis behavior that can catalyze the V(Ⅱ)-V(Ⅴ) redox reaction showed by cyclic voltammograms. This article studied the impedance of the modified electrode by electrochemical impedance spectroscopy (EIS), and approved that the electrode modified by Co^2+ and Mn^2+ has a lower charge transfer resistance than the non-modified electrode. The effect of average particle size distribution is at lower frequencies that the slope of Warburg impedance is reduced by large particle size distribution. The voltage efficiency of the Co^2+ modified electrode test cell is 81.5%, which is higher than that of the non-modified electrode.展开更多
A new chemically modified electrode(CME) immobilized on the surface of multi-wall carbon nanotubes functionalized with carboxylic groups was fabricated. The results indicate that the CME exhibits efficiently electroca...A new chemically modified electrode(CME) immobilized on the surface of multi-wall carbon nanotubes functionalized with carboxylic groups was fabricated. The results indicate that the CME exhibits efficiently electrocatalytic oxidation of 6-mercaptopurine(6-MP). The CME can be used as the working electrode in the liquid chromatography for the determination of 6-MP. The peak current of 6-MP is linearly changed with its concentration ranging from 4.0×10 -7 to 1.0×10 -4 mol/L with the calculated detection limit (S/N=3) of 2.0×10 -7 mol/L. Coupled with microdialysis sampling, the method has been successfully applied to assessing the content of 6-MP in rat blood.展开更多
The chemically modified electrode (CME) which was constructed by covalent attaching erythromycin (ERM) to the glassy carbon (GC) surface was investigated in Tris-HCl buffer (pH=6.0) by cyclic voltammetry (CV) and diff...The chemically modified electrode (CME) which was constructed by covalent attaching erythromycin (ERM) to the glassy carbon (GC) surface was investigated in Tris-HCl buffer (pH=6.0) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In the potential range of -0.5~0.4V, CME yields a pair of stable redox wave. It is the carbonyl group of the ERM molecule immobilized on the GC surface that undergoes two electron redox process involving two protons. The interaction of CME with DNA was also studied by DPV. The CME shows the same interaction with DNA as that in the solution. And the result was proved by fluorescence.展开更多
Electrochemistry of nitrate reductases (NR) incorporated into 2-aminoethanethiol self-assembled on the gold electrode and polyacrylamide cast on the pyrolytic graphite electrode was examined. NR on chemical modified ...Electrochemistry of nitrate reductases (NR) incorporated into 2-aminoethanethiol self-assembled on the gold electrode and polyacrylamide cast on the pyrolytic graphite electrode was examined. NR on chemical modified electrode showed electrochemical cyclic voltammetric responses in phosphate buffers.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2013CB328803)
文摘An efficient interface modification is introduced to improve the performance of polymeric thin film transistors. This efficient interface modification is first achieved by 4-fluorothiophenol(4-FTP) self-assembled monolayers(SAM) to chemically treat the silver source–drain(S/D) contacts while the silicon oxide(SiO2) dielectric interface is further primed by either hexamethyldisilazane(HMDS) or octyltrichlorosilane(OTS-C8). Results show that contact resistance is the dominant factor that limits the field effect mobility of the PTDPPTFT4 transistors. With proper surface modification applied to both the dielectric surface and the bottom contacts, the field effect mobilities of the bottom-gate bottom-contact PTDPPTFT4 transistors were significantly improved from 0.15 cm^2·V^-1·s^-1 to 0.91 cm^2·V^-1·s^-1.
基金supported by the National Basic Research Program of China(Grant No.2007CB209700)the Graduate Student Innovation Foundation of Jiangsu Province,China(Grant No.CX09B_075Z)the Research Funding of Nanjing University of Aeronautics and Astronautics,China(Grant No.NS2010165)
文摘A novel electrode material based on chemically modified graphene (CMG) with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the aminophenyl groups of p-phenylenediamine. Palladium nanoparticles with an average diameter of 4.2 nm are deposited on the CMG by a liquid-phase borohydride reduction. The electrocatalytic activity and stability of the Pd/CMG composite towards formic acid oxidation are found to be higher than those of reduced graphene oxide and commercial carbon materials such as Vulcan XC-72 supported Pd electrocatalysts.
文摘The opticai properties of C,, chemicaiiy modified poiystyrene(C,, -PS copolymer) and the parent polystyrene (PS) films have been investigated.Addition of bulky C,, moiety, a special functional group, to the polystyrene by anovel organometallic reaction modified considerably the optical property of theparent polystyrene. The lattice periodicity of pure PS film is subject to someperturbation or distortion in varying degrees due to the covalent attachInent of bulkyC,, moiety to the polymer backbone. C,,-PS copolymer possesses a new energy ba-ndstructure with indirect forbidden band when compared with the parent PS.
文摘Chemically modified clay(CMC) was used as an adsorbent for the removal of Astrazon Golden Yellow 7GL(AGY-7GL), which is a basic dye from wastewater. For this purpose, the chemically modified clay was first characterized by determining zero point of charge(p Hzpc), and using BET, SEM and FTIR. Then effects of operational parameters on adsorption of AGY-7GL were studied in a batch system. The effect of various parameters such as contact time(0-180 min), pH(2-8), temperature(293-323 K), CMC concentration(0.075-0.5 mg/L) and initial AGY-7GL concentration(75-250 mg/L) were investigated on the adsorption efficiency and capacity adsorption of CMC for the removal of AGY-7GL. Thermodynamic and kinetic parameters were calculated from the results of the adsorption experiment. The evaluation of kinetic models shows that this data best fits the pseudo-second-order model. It is determined that the adsorption equilibrium data works very well with the nonlinear Freundlich isotherm model. Thermodynamic parameters such as ?H^0(19.0 k J/mol), ?G^0(-28.8 k J/mol) and ?S^0(0.148 k J/mol) were also determined. According to the experimental results, it is concluded that CMC could be used as an alternative low cost potential adsorbent for the removal of AGY-7GL from wastewater.
文摘The electrochemical behaviors of Eu3+ on Eastman AQ-29D/glassy carbon(GC) chemically modified electrode(CME) were studied. It was found that the reduction-oxidation process of Eu3+ is in a semi-infinite condition in 0.1 mol/L NaCIO4 supporting electrolyte(pH 4.4). The calibration curve was linear over the range 1.0×10-7 to 1.0×105 mol/L of Eu3+.The charge transport apparent diffusion coefficient of Eu3+ in the polymer film was determined to be(3.2±1.1)×10-11cm2/s by chronocoulometry.
基金the Project of Natural Science Foundation of Gansu Province of their financial supports(No. 096RJZA117)
文摘The electrocatalytic oxidation of methanol at the platinum electrode modified with Eu-Fe cyanide-bridged binuclear complexes (Eu-Fe film) was investigated for the first time by cyclic voltammetry.Compared with the bare platinum electrode,the results showed that the modified electrode had excellent electrocatalytic activity for the oxidation of methanol;the oxidation peak potential shifted more negatively and the peak current increased about twenty times.The electrooxidation of methanol at the modified elect...
基金supported by National Natural Science Foundation of China(No.20775070)Zhejiang Provincial Natural Science Foundation of China(No.Y407153)sponsored by Zhejiang Provincial Assay Foundation of China(No.2007F70017)
文摘A La^3+-Cu/Pt modified electrode was fabricated by electrodepositing process in CuS04 solution by adding a small amount of lanthium compound, and it was employed for direct current (DC) amperometric detection of spectinomycin by anion-exchange chromatography. Without derivatization, this method can simultaneously determine the main component and impurities in spectinomycin pharmaceutical raw material. Ease of preparation, being applied in DC detection mode and good catalytic stability confirmed the interests of this modified electrode as amperometric sensor for the determination of spectinomycin.
文摘A PCV-modified electrode was simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al and the peak potentials remain the same. The decreasing of Delta i(p) is linear with Al concentration in the range of 1 x 10(-8) similar to 1 x 10(-7) mol/L. The detection limit is 5 x 10(-9) mol/L and the relative standard deviation for 4 x 10(-8) mol/L Al is 2.9% (n=8). No serious interference was found. The determination of Al in water samples is reported.
基金the National Natural Science Foundation of China
文摘The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported. The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity. The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_(pa)= 220 mV, E_(pc)=95 mV and the formal potential E^(o')= 157. 5 mV(vs. SCE) at 100 mV/s in the buffer solution of pH 7. 0. The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry. Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5. 0 × 10^(-6) to 5. 0 × 10^(-4) mol/L, and the detection limit is 1. 0 ×10^(-6) mol/L at S/N=3. Normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca. 30. 8: 1.
文摘An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb2+ and Cd2+ were accumulated at the surface of the modified electrode via formation of chemical complexes with calix[6]arene, and reduced at 1.40 V. During the following anodic potential sweep, reduced lead and cadmium were oxidized, and two well-defined striping peaks appeared at about ?0.60 V and ?0.84 V. Compared with a bare carbon paste electrode, the calix[6]arene modified CPE greatly improves the sensitivity of determining lead and cadmium. The stripping peak currents change linearly with the concentration of Pb2+ 3.0×10?8–8.0×10?6 mol·L?1 and with that of Cd2+ 6.0×10?8–1.0×10?5 mol ·L?1. The detection limits of Pb2+ and Cd2+ are found to be 8.0×10?9 mol·L?1 and 2.0×10?8 mol·L?1, respectively. The modified carbon paste electrode was applied to determine trace levels of lead and cadmium in water samples. Comparing with that of atomic absorption spectrometry, the results suggests that the calix[6]arene modified CPE has great potential for the practical sample analysis. Key words lead(II) - cadmium(II) - calix[6]arene - differential pulse stripping voltammetry - chemically modified electrode CLC number O 657.15 Foundation item: Supported by the National Natural Science Foundation of China (60171023)Biography: JI Xiao-bo (1980-), male, Master, research direction: electroanalytical chemistry.
基金Authors greatly appreciate the supports from the National Natural Science Foundation of China Returnee Foundation of Ministry of Education of China and Analytical Foundation of Nanjing University.
文摘s: A new method for the preparation of an organic-inorganic composite film of the heteropolyanion has been developed by modifying P(Mo2O7)6-7 to the indium tin oxide (ITO) electrode surface. The modified electrode displayed a strong catalytic activity towards the reduction of IO3-. In the range of 1.0?0-6~5?0-4mol/L, the catalytic current was linear proportional to the IO3- concentration.
文摘A novel fibroin modified electrode with ion recognition was reported. The membranewith isoelectric point of pH 4.5, was modified on graphite and carbon fiber electrodes. ThepH-responsive ion recognition of the modified electrode was investigated by use of someneurocompounds. The fibroin carbon fiber electrode has been used for in-vivo determination.
文摘It was newly found that the electrodes modified by applying ethanol solutions of Nationcontaining os(bpy)32+ onto the substrate electrode (the one-step method) show two pairs of stableredox peaks of Os(bpy)32+/3+ on cyclic voltammogram near 0.54V and 0.25V, respectively. Thesemoditied electrodes can effectively mediate and catalyze the first and second steps of nitritereduction in acidic media in the potential region 0-0.9V when the loading in the coating (X=F(Os2+) / F(SO3-)) and pH in solution are below 0. 17 and 4, respectively. When X is between 0.33and 0. 17. only the current peak near 0.54V appears regardless of solution pH and only the first stepof NO2 reduction is catalyzed. Thus the modified electrode provides a very useful flexibility thatone can control the reaction pathway and catalytic activity of nitrite reduction by simply changingthe concentration of the mediator in the coating.
文摘Electrochemical behaviours of Europium-ferrocene derivative complex chemically modified electrodes were studied in the paper. Various factors which affect the voltammetry of the thin film modified electrodes, and the charge transport process of the thin film electrode were discussed. Size of the hydrated anion (counter ion), concentration of the electrolyte, swelling property of the film in the solvent and thickness of the film have significant effects on the voltammetry of the thin film electrode. Electrochemical behaviours of europium-ferrocene derivative compelx chemically modified electrode were studied in an aqueous solution. When scan ning between 0-0.8 V (vs. SCE), experimental results indicate that the chemically modified electrode has good stability and reproducibility. The apparent rate constant of electrode reaction is deteminedd to be 6.7×10-1 s-1.
基金This work was financially supported by the National Natural Science Foundation of China (No. 90510001).
文摘Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite electrode has high specific surface area and high current density. The electrode modified by transition metallic ions has improved catalysis behavior that can catalyze the V(Ⅱ)-V(Ⅴ) redox reaction showed by cyclic voltammograms. This article studied the impedance of the modified electrode by electrochemical impedance spectroscopy (EIS), and approved that the electrode modified by Co^2+ and Mn^2+ has a lower charge transfer resistance than the non-modified electrode. The effect of average particle size distribution is at lower frequencies that the slope of Warburg impedance is reduced by large particle size distribution. The voltage efficiency of the Co^2+ modified electrode test cell is 81.5%, which is higher than that of the non-modified electrode.
文摘A new chemically modified electrode(CME) immobilized on the surface of multi-wall carbon nanotubes functionalized with carboxylic groups was fabricated. The results indicate that the CME exhibits efficiently electrocatalytic oxidation of 6-mercaptopurine(6-MP). The CME can be used as the working electrode in the liquid chromatography for the determination of 6-MP. The peak current of 6-MP is linearly changed with its concentration ranging from 4.0×10 -7 to 1.0×10 -4 mol/L with the calculated detection limit (S/N=3) of 2.0×10 -7 mol/L. Coupled with microdialysis sampling, the method has been successfully applied to assessing the content of 6-MP in rat blood.
文摘The chemically modified electrode (CME) which was constructed by covalent attaching erythromycin (ERM) to the glassy carbon (GC) surface was investigated in Tris-HCl buffer (pH=6.0) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In the potential range of -0.5~0.4V, CME yields a pair of stable redox wave. It is the carbonyl group of the ERM molecule immobilized on the GC surface that undergoes two electron redox process involving two protons. The interaction of CME with DNA was also studied by DPV. The CME shows the same interaction with DNA as that in the solution. And the result was proved by fluorescence.
基金We are grateful to the NNSFC (29973026), BNSF (2992007) Foundation for University Key Teacher by the Ministry of Education for the provision of financial support.
文摘Electrochemistry of nitrate reductases (NR) incorporated into 2-aminoethanethiol self-assembled on the gold electrode and polyacrylamide cast on the pyrolytic graphite electrode was examined. NR on chemical modified electrode showed electrochemical cyclic voltammetric responses in phosphate buffers.