Papers - Serizawa, Nobuyuki

EQCM measurement of Ag (I) /Ag reaction in an amide-type room-temperature ionic liquid

Serizawa Nobuyuki, Katayama Yasushi, Miura Takashi

Journal of the Electrochemical Society 156 ( 11 )  2009

ISSN  0013-4651

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<p>Electrodeposition of silver was investigated using an impedance technique (separately excited, passive technique) electrochemical quartz crystal microbalance (EQCM) in a room-temperature ionic liquid. The mass changes during silver deposition and dissolution were observed with the current efficiencies of nearly 100% during potential sweep, constant potential step, and constant current step experiments. The product of the viscosity and density of the electrolyte near the electrode, ν_Lρ_L, can be estimated by the resonance resistance, which can be monitored simultaneously with the resonance frequency. The change in the ν_Lρ _L value during silver deposition was consistent with the change in the calculated concentration of Ag(I) near the electrode. During the outer-sphere electron-transfer reaction between ferrocenium and ferrocene, no significant changes in the mass and the L_{ρ L} value were observed.</p>

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Electrochemistry of Sn(II)/Sn in a hydrophobic room-temperature ionic liquid

Tachikawa Naoki, Serizawa Nobuyuki, Katayama Yasushi, Miura Takashi

Electrochimica Acta 53 ( 22 ) 6530 - 6534 2008.09

ISSN  0013-4686

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<p>The electrochemical reaction of Sn(II)/Sn was investigated in a room-temperature ionic liquid, 1-n-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) at 25 °C. The anodic dissolution of Sn metal proceeded by a two-electron transfer reaction with a current efficiency of nearly 100%. Electrodeposition of Sn on a Cu substrate is possible in BMPTFSI containing Sn(II). The formal potential of the Sn(II)/Sn is -0.57 V vs. Ag/Ag(I). The diffusion coefficient of Sn(II) was estimated to be ∼ × 10^-7 cm² s^-1 from chronoamperometric and chronopotentiometric techniques. The initial stage of nucleation of Sn on a polycrystalline Pt substrate was found to be classified into a three-dimensional progressive nucleation under diffusion control by chronoamperometry, suggesting the rate of nucleation is faster than that of crystal growth.</p>

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