The reduction mechanism of Ir in the NaCl-KCl-IrCl3 molten salt was investigated by cyclic voltammetry and chronopotentiometry, and Ir film was deposited effectively on platinum in potentiostatic mode. The morphology ...The reduction mechanism of Ir in the NaCl-KCl-IrCl3 molten salt was investigated by cyclic voltammetry and chronopotentiometry, and Ir film was deposited effectively on platinum in potentiostatic mode. The morphology and constitution of Ir film were examined by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. It is found that the reduction mechanism of Ir（III） is a three-electron step and electro reaction is a reversible diffusion controlled process; the diffusion coefficients of Ir（III） at 1083, 1113, 1143 and 1183 K are 1.56×10-4, 2.23×10-4, 2.77×10-4 and 4.40×10-4 cm2/s, respectively, while the activation energy of the electrode reaction is 102.95 kJ/mol. The compacted Ir film reveals that the applied potential greatly affects the deposition of Ir, the thickness of Ir film deposited at the potential of reduction peak is the highest, the temperature of the molten salt also exerts an influence on deposition, the film formed at a lower temperature is thinner, but more micropores would occur on film when the temperature went too high.展开更多
The alloying process of Mg-La in NaCl-KCl-MgCl_(2)-LaCl_(3)(NKML)melts during electroreduction was elucidated using electrochemical techniques and deep potential molecular dynamics(DPMD)simulations.In the NKML system,...The alloying process of Mg-La in NaCl-KCl-MgCl_(2)-LaCl_(3)(NKML)melts during electroreduction was elucidated using electrochemical techniques and deep potential molecular dynamics(DPMD)simulations.In the NKML system,the Mg^(2+)/La^(3+)electrodeposition on the tungsten(W)electrode at 973 K was found to be a one-step process.The nucleation of metal ions on the electrode surface followed an instantaneous nucleation mode and was not influenced by the alloying process.The redox potential and underpotential deposition behavior of the metal ions in the NKML system were accurately predicted by the DPMD simulations,confirming the alloying process of the Mg-La.Additionally,scanning electron microscopy with energy dispersive spectroscopy(SEM-EDS)analysis results confirmed that the cathodic deposits consisted of a bright phase and a dark phase,corresponding to the Mg-La alloys and Mg,respectively.The distribution of electrolytic products suggests that the cathodic deposit initially favors the Mg phase,with the Mg-La alloy forming more easily when the Mg source in the melt is depleted.展开更多
A process comprising selective chlorination and molten salt electrolysis was proposed to develop an efficient and environmental-friendly technology for zinc recovery from metallurgical dusts.The theoretical feasibilit...A process comprising selective chlorination and molten salt electrolysis was proposed to develop an efficient and environmental-friendly technology for zinc recovery from metallurgical dusts.The theoretical feasibility of this technology was firstly estimated based on thermodynamic fundamentals.Subsequently,the electrochemical behavior of Zn^(2+)on tungsten electrode was investigated in molten NaCl-KCl eutectic at 973 K by many electrochemical transient methods.The results showed that the reduction of Zn^(2+)on tungsten electrode was found to be a one-step process exchanging two electrons with the initial reduction potential of-0.74 V(vs Ag/AgCl),and the electrode process was considered as quasi-reversible and controlled by diffusion.The diffusion coefficient of Zn^(2+)ions in the melts was determined in the order of 10^(-5)cm^(2)/s.Finally,the electrolytic preparation of zinc was carried out by potentiostatic electrolysis in molten NaCl-KCl-ZnCl_(2)eutectic at-1.6 V(vs Ag/AgCl).Spheroidic granular metal with silver-white luster was attained after electrolysis for 9.5 h,and identified as pure Zn.The present study confirms that it is practically feasible to extract pure zinc metal by direct electrolysis of ZnCl_(2)in molten NaCl-KCl eutectic,and provides a valuable theoretical reference for the efficient recovery of zinc from metallurgical dusts.展开更多
文摘The reduction mechanism of Ir in the NaCl-KCl-IrCl3 molten salt was investigated by cyclic voltammetry and chronopotentiometry, and Ir film was deposited effectively on platinum in potentiostatic mode. The morphology and constitution of Ir film were examined by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. It is found that the reduction mechanism of Ir（III） is a three-electron step and electro reaction is a reversible diffusion controlled process; the diffusion coefficients of Ir（III） at 1083, 1113, 1143 and 1183 K are 1.56×10-4, 2.23×10-4, 2.77×10-4 and 4.40×10-4 cm2/s, respectively, while the activation energy of the electrode reaction is 102.95 kJ/mol. The compacted Ir film reveals that the applied potential greatly affects the deposition of Ir, the thickness of Ir film deposited at the potential of reduction peak is the highest, the temperature of the molten salt also exerts an influence on deposition, the film formed at a lower temperature is thinner, but more micropores would occur on film when the temperature went too high.
基金support from the National Natural Science Foundation of China(No.U20A20147).
文摘The alloying process of Mg-La in NaCl-KCl-MgCl_(2)-LaCl_(3)(NKML)melts during electroreduction was elucidated using electrochemical techniques and deep potential molecular dynamics(DPMD)simulations.In the NKML system,the Mg^(2+)/La^(3+)electrodeposition on the tungsten(W)electrode at 973 K was found to be a one-step process.The nucleation of metal ions on the electrode surface followed an instantaneous nucleation mode and was not influenced by the alloying process.The redox potential and underpotential deposition behavior of the metal ions in the NKML system were accurately predicted by the DPMD simulations,confirming the alloying process of the Mg-La.Additionally,scanning electron microscopy with energy dispersive spectroscopy(SEM-EDS)analysis results confirmed that the cathodic deposits consisted of a bright phase and a dark phase,corresponding to the Mg-La alloys and Mg,respectively.The distribution of electrolytic products suggests that the cathodic deposit initially favors the Mg phase,with the Mg-La alloy forming more easily when the Mg source in the melt is depleted.
基金the financial support from the Natural Science Foundation of Anhui Province, China (No. 2008085ME170)the Anhui Special Support Plan, China (No. T000609)the National Natural Science Foundation of China (No. 51204002
文摘A process comprising selective chlorination and molten salt electrolysis was proposed to develop an efficient and environmental-friendly technology for zinc recovery from metallurgical dusts.The theoretical feasibility of this technology was firstly estimated based on thermodynamic fundamentals.Subsequently,the electrochemical behavior of Zn^(2+)on tungsten electrode was investigated in molten NaCl-KCl eutectic at 973 K by many electrochemical transient methods.The results showed that the reduction of Zn^(2+)on tungsten electrode was found to be a one-step process exchanging two electrons with the initial reduction potential of-0.74 V(vs Ag/AgCl),and the electrode process was considered as quasi-reversible and controlled by diffusion.The diffusion coefficient of Zn^(2+)ions in the melts was determined in the order of 10^(-5)cm^(2)/s.Finally,the electrolytic preparation of zinc was carried out by potentiostatic electrolysis in molten NaCl-KCl-ZnCl_(2)eutectic at-1.6 V(vs Ag/AgCl).Spheroidic granular metal with silver-white luster was attained after electrolysis for 9.5 h,and identified as pure Zn.The present study confirms that it is practically feasible to extract pure zinc metal by direct electrolysis of ZnCl_(2)in molten NaCl-KCl eutectic,and provides a valuable theoretical reference for the efficient recovery of zinc from metallurgical dusts.
