Examination of the Extinction Process of Ionic Vacancy by the Cyclotron MHD Electrode

Abstract

From the lifetime measurement of ionic vacancy with a new type of electrode called cyclotron magnetohydrodynamic electrode (MHDE), two extinction processes of ionic vacancy were clarified; one is the decay to the initial state, and the other is the conversion to nanobubbles with the collision of the ionic vacancies. As a result, in copper electrodeposition, the formation time of the nanobubble was obtained as 0.072 s, whereas the intrinsic lifetime of the ionic vacancy without collision was determined as 8.6 s. Then, the creation-extinction process of the ionic vacancy in the diffusion layer was calculated, so that it was concluded that ionic vacancies act as lubricant with a network structure without diffusion, and the frictionless sliding of the solution begins at a constant vacancy concentration of 1.73 ± 0.36 mol m -3 .

Non-electrochemical Nanobubble Formation in Ferricyanide/Ferrocyanide Redox Reaction by the Cyclotron Effect under a High Magnetic Field

“…8 In all cases, the collision between ionic vacancies decreased the lifetime down to 1/100th of the intrinsic value. As predicted by the preceding papers, 6,10,11 these results suggested that nanobubbles arise from the collision of ionic vacancies. However, nanobubbles are too small to observe, so that for the visualization of the bubble formation, some other process to yield much larger bubbles was required.…”

“…In cathodic reactions such as copper deposition, negatively charged ionic vacancies are created, yielding negatively charged nanobubbles surrounded by positively charged ionic clouds. Due to positively charged outer ionic clouds, 6,11 The first two authors contributed equally to this work. nanobubbles are once adsorbed on the negatively charged electrode in a cathodic polarization.…”

“…58 As a result, in a 100 mol m ¹3 supporting electrolyte solution at 27°C, for ionic vacancies with one and two unit charges, their average diameters were determined about 0.4 and 0.75 nm, respectively, which were in good agreement with theoretical predictions. 5,9 On the other hand, the lifetimes of the vacancies were measured by cyclotron MHD (magnetohydrodynamic) electrode (CMHDE), 9,10 which was composed of a pair of concentric circular electrodes under a vertical magnetic field. The lifetimes were obtained by measuring the circumferential velocity of the solution driven by a Lorentz force on the free surface covered with ionic vacancies, e.g., ca.…”

Microbubble Formation from Ionic Vacancies in Copper Electrodeposition under a High Magnetic Field

“…4,5 Ionic vacancies flowing with the solution collide with ionic vacancies newly created on the electrode, transformed into nanobubbles. As a result, the intrinsic lifetime without collision is about 1.0 s, whereas the formation time of nanobubble in the case of perfect collision is about 10 ms.…”

“…Recently, the measurements of their partial molar volumes and lifetimes have revealed that ionic vacancies are created with electrode reactions. [1][2][3][4][5] At the same time, the nanobubble formation from supersaturated ionic vacancies has been theoretically clarified. 6,7 However, due to their sizes of about 0.1 nm and lifetimes of about 1 s, the direct observation of ionic vacancies is difficult.…”