Chiral behaviors of magnetoelectrodeposited Ag film electrodes were investigated for the electrochemical reactions of glucose and cysteine. The Ag films were electrodeposited under a magnetic field of 2 T perpendicula...Chiral behaviors of magnetoelectrodeposited Ag film electrodes were investigated for the electrochemical reactions of glucose and cysteine. The Ag films were electrodeposited under a magnetic field of 2 T perpendicular to the electrode surface at various potentials 0f-0.06-0.4 V （vs Ag I Ag＋）. The current-time curves during the electrodeposition and the surface morphology of the films implied that the film growth was considerably affected by the micro-MHD （magnetohydrodynamic） effect. Such Ag films were employed as an electrode, and voltammograms of glucose and cysteine were examined. Chiral behavior was clearly observed as current difference between the enantiomers on the film electrodes prepared at electrodeposition potentials less than -0.1 V. Such electrochemical chirality disappeared after the oxidation and reduction of the surface monolayer, and this fact indicates that the chiral sites must be just on the film surface.展开更多
The roles of the rotations in the process of chirality appearance in magnetoelectrodeposition were theoretically clarified.Electrodeposition in a vertical magnetic field induces a macroscopic fluid rotation called ver...The roles of the rotations in the process of chirality appearance in magnetoelectrodeposition were theoretically clarified.Electrodeposition in a vertical magnetic field induces a macroscopic fluid rotation called vertical MHD flow(VMHDF) over the electrode surface.Inside the rotation,minute numerous micro-vortexes called micro-MHD flow(MMHDF) arise from 2D and 3D nucleation,which interact with the mass flux of metallic ion,yielding chiral deposits with the characteristic features called micro- and nano-mystery circles.Generally,numerous vortexes always keep chiral symmetry,forming four types of vortexes,i.e.,with the combination of upward or downward and clockwise or counterclockwise.However,ionic vacancy acting as an atomic scale lubricant is created in electrodeposition,which gives a restriction to the vortexes;the bottom of an upward vortex covered with ionic vacancies becomes a free surface without friction,whereas the bottom of a downward vortex exposed without ionic vacancies remains rigid with friction.The rotation of VMHDF donates a precession to the upward vortexes to rotate in the same direction,which finally yield a chiral deposit.The similar effect to that of VMHDF can be expected for the system rotation(SR),where an electrolytic cell rotates in a vertical magnetic field.In this case,the SR gives the reverse rotation to the upward vortexes,so that a deposit with reverse chirality is obtained.展开更多
Cu films were electrodeposited under a magnetic field of 5 T on the Pt disc electrodes with diameters of 3 mm ~ 25 μm.Such magnetoelectrodeposited(MED) Cu films were employed as an electrode,and cyclic voltammograms ...Cu films were electrodeposited under a magnetic field of 5 T on the Pt disc electrodes with diameters of 3 mm ~ 25 μm.Such magnetoelectrodeposited(MED) Cu films were employed as an electrode,and cyclic voltammograms were measured for the electrochemical reactions of an amino acid of alanine.Chiral behavior was observed as oxidation current difference between the enantiomers.Clear magnetoelectrochemical chirality was observed on the micro-disk electrode and on the kinetic-controlled electrode process of alanine.The chiral response was durable for more than 10 cycles of the consecutive voltammetric measurements of the enantiomers.展开更多
文摘Chiral behaviors of magnetoelectrodeposited Ag film electrodes were investigated for the electrochemical reactions of glucose and cysteine. The Ag films were electrodeposited under a magnetic field of 2 T perpendicular to the electrode surface at various potentials 0f-0.06-0.4 V （vs Ag I Ag＋）. The current-time curves during the electrodeposition and the surface morphology of the films implied that the film growth was considerably affected by the micro-MHD （magnetohydrodynamic） effect. Such Ag films were employed as an electrode, and voltammograms of glucose and cysteine were examined. Chiral behavior was clearly observed as current difference between the enantiomers on the film electrodes prepared at electrodeposition potentials less than -0.1 V. Such electrochemical chirality disappeared after the oxidation and reduction of the surface monolayer, and this fact indicates that the chiral sites must be just on the film surface.
文摘The roles of the rotations in the process of chirality appearance in magnetoelectrodeposition were theoretically clarified.Electrodeposition in a vertical magnetic field induces a macroscopic fluid rotation called vertical MHD flow(VMHDF) over the electrode surface.Inside the rotation,minute numerous micro-vortexes called micro-MHD flow(MMHDF) arise from 2D and 3D nucleation,which interact with the mass flux of metallic ion,yielding chiral deposits with the characteristic features called micro- and nano-mystery circles.Generally,numerous vortexes always keep chiral symmetry,forming four types of vortexes,i.e.,with the combination of upward or downward and clockwise or counterclockwise.However,ionic vacancy acting as an atomic scale lubricant is created in electrodeposition,which gives a restriction to the vortexes;the bottom of an upward vortex covered with ionic vacancies becomes a free surface without friction,whereas the bottom of a downward vortex exposed without ionic vacancies remains rigid with friction.The rotation of VMHDF donates a precession to the upward vortexes to rotate in the same direction,which finally yield a chiral deposit.The similar effect to that of VMHDF can be expected for the system rotation(SR),where an electrolytic cell rotates in a vertical magnetic field.In this case,the SR gives the reverse rotation to the upward vortexes,so that a deposit with reverse chirality is obtained.
文摘Cu films were electrodeposited under a magnetic field of 5 T on the Pt disc electrodes with diameters of 3 mm ~ 25 μm.Such magnetoelectrodeposited(MED) Cu films were employed as an electrode,and cyclic voltammograms were measured for the electrochemical reactions of an amino acid of alanine.Chiral behavior was observed as oxidation current difference between the enantiomers.Clear magnetoelectrochemical chirality was observed on the micro-disk electrode and on the kinetic-controlled electrode process of alanine.The chiral response was durable for more than 10 cycles of the consecutive voltammetric measurements of the enantiomers.
