DMI−LiNO3离子液体类似物室温电沉积钕铁硼薄膜

研究1,3-二甲基-2-咪唑啉酮(DMI)−LiNO_(3)离子液体类似物在室温条件下电沉积钕铁硼薄膜的可行性和反应机理。结果表明,循环伏安曲线中−1.83 V(vs Ag)处的还原峰对应于Fe(II)被还原为金属Fe,−2.01 V(vs Ag)处的还原峰对应于B(III)被还原为B。Fe(II)和B(III)的电化学还原反应是受扩散控制的不可逆过程,313 K下Fe(II)和B(III)的扩散系数分别为3.03×10^(−6)和6.74×10^(−7) cm^(2)/s。此外,XRD分析表明,在DMI−LiNO_(3)−Nd(CF_(3)SO_(3))_(3)−FeCl_(2)−H_(3)BO_(3)体系中以铝为基底电沉积2 h的产物含有NdFe_(3)B_(3);SEM和EDS分析表明,阴极产物中Nd、Fe和B元素呈均匀分布;XPS分析表明,钨基底表面中Nd、Fe和B的质量分数分别为27.44%、27.90%和7.51%。

Physicochemical properties of 1,3-dimethyl-2-imidazolinone−ZnCl_(2)solvated ionic liquid and its application in zinc electrodeposition

Zinc chloride(ZnCl_(2))was dissolved in the 1,3-dimethyl-2-imidazolinone(DMI)solvent,and the metallic zinc coatings were obtained by electrodeposition in room-temperature ambient air.The conductivity(σ),viscosity(η),and density(ρ)of the DMI−ZnCl_(2)solvated ionic liquid at various temperatures(T)were measured and fitted.Furthermore,cyclic voltammetry was used to study the electrochemical behavior of Zn(II)in the DMI−ZnCl_(2)solvated ionic liquid,indicating that the reduction of Zn(II)on the tungsten electrode was a one-step two-electron transfer irreversible process.XRD and SEM−EDS analysis of the cathode product confirmed that the deposited coating was metallic zinc.Finally,the effects of deposition potential,temperature and duration on the morphology of zinc coatings were investigated.The results showed that a dense and uniform zinc coating was obtained by potentiostatic electrodeposition at−2 V(vs Pt)and 353 K for 1 h.

Electrochemical behavior of tantalum in ethylene carbonate and aluminum chloride solvate ionic liquid

To investigate the electrochemical reduction mechanism of Ta(Ⅴ)in ethylene carbonate and aluminum chloride(EC-AlCl3)solvate ionic liquid,cyclic voltammetry experiments were conducted on a tungsten working electrode.Four reduction peaks were observed in the cyclic voltammogram of the EC-AlCl3-TaCl5 ionic liquid.The reduction peaks at-0.55,-0.72,and-1.12 V(vs Al)were related to the reduction of Ta(Ⅴ)to tantalum metal by three stages including the formation of Ta(Ⅳ)and Ta(Ⅲ)complex ions.The reduction of Ta(Ⅲ)to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10^-7 cm^2/s at 323 K,and the diffusion activation energy was 77 k J/mol.Moreover,the cathode products at 323 K were characterized by scanning electron microscopy,energy-dispersive spectroscopy,and X-ray photoelectron spectroscopy.The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at-0.8 V for 2 h.

Physicochemical properties of DMI-LiNO_(3) solvated ionic liquid and its application in electrodeposition of neodymium at room temperature

The density,conductivity,and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate(DMILiNO_(3))solvated ionic liquid were measured as a function of temperature.Additionally,the electrochemical mechanism and electrodeposition of neodymium from the DMI-LiNO_(3) solvated ionic liquid were investigated.Cyclic voltammetry results indicate that the electrochemical reduction of Nd(Ⅲ)is irreversible and proceeds via one-step with three-electron transfer,which is controlled by diffusion with a diffusion coefficient of 5.08×10^(-8) cm^(2)/s.Energydispersive X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at-4 V(vs Ag)using the DMI-LiNO_(3)-Nd(CF_(3)SO_(3))_(3) solvated ionic liquid contains metallic neodymium.

Raman spectroscopy and quantum chemical calculation on YCl_(3)-KCl molten salt system

The knowledge on the ionic structure of YCl_(3)-KCl molten system is of guiding significance for the practical production of yttrium metals and yttrium alloys via molten salt electrolysis using this system as electrolyte.In this paper,the theoretical Raman spectra of the ionic groups which may exist in YCl_(3)-KCl molten system are simulated by quantum chemical calculation using Gaussian09 and Gauss View 5.0 programs based on density functional theory(DFT).Then the ionic structures of 20 mol%-60 mol%YCl_(3)-KCl molten salt systems are studied by comparing the Raman shift values of the bands in the theoretical Raman spectra of different ionic groups with the experimental spectra of this system.YCl_(6)^(3-),Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)are thought to exist in the molten system.With the increase of temperature,the relative content of YCl_(6)^(3-)ionic groups increases while those of Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)ionic groups decrease.Moreover,the"lifetime"of all ionic groups decreases within the temperature range of 692-730℃.Meanwhile,the relative contents of Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-)and Y_(2)Cl_(9)^(3-)increase with the increase of YCl_(3)content,while that of YCl_(6)^(3-)decreases.The wave function analysis of the four ionic groups(YCl_(6)^(3-),Y_(2)Cl_(7)^(-),Y_(2)Cl_(8)^(2-),and Y_(2)Cl_(9)^(3-))is carried out by Multiwfn program.The net charge in each group,the direction of electron migration during the formation of each group,the sites where electrophilic and nucleophilic reactions are most likely to occur in each ionic group,and the order of bond breaking during chemical reactions for the four groups are obtained.