| 研究実績の概要 |
Electrochemically formed hydrogen nanobubbles were detected by re-oxidation charge at Pt(111), polycrystalline platinum and platinized platinum electrodes. Non-electrochemical dissolution time course of the hydrogen nanobubbles was measured by open circuit potentials of each electrodes. The bubble dissolution was proceeding as two types of diffusion; the molecular diffusion to solution and two-dimensional atomic spill over at the platinum surfaces. In spite that the surface structures between the atomically flat Pt(111) and fractal surface of the platinized platinum electrodes were ultimately different, the surface densities of the hydrogen nanobubbles were almost identical. However, at the polycrystalline platinum, the density increased as the increase in the number of steps accomplished by surface roughening. The hydrogen nanobubbles were proved to exist at platinum and sulfuric acid aqueous solution without any artifact, such as hydrophobic contaminant. Although the electrochemical reaction of the normal hydrogen electrode (NHE) partly proceeded heterogeneously on the three phases boundary around the hydrogen nanobubbles, the identical density of the bubble at the atomically flat and the fractal surface supported the validity of the IUPAC recommendation for the preparation of NHE to use the platinzed platinum electrode, in stead of the polycrystalline electrode.
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