Abstract
The electrooxidation of hydrogen on platinum and gold electrodes is comparatively described in this paper. The reaction is faster on platinum than on the gold surface, because the reactive diffuses inside of the gold metal. This process is complicated with the lift of surface reconstruction of the (100) plane, which allows the fast penetration of the H atoms through the more open surface. The diffusion limiting current is then discontinued and the current falls. On platinum, the current fall occurs simultaneously with the metal oxide formation. It is assumed that the hydrogen helps the adsorbed OH group formation, which is the first step of metal oxidation, and it has been called “incipient hydrous oxide” (IHO). Current begins to fall slowly at the (IHO) potential. At higher potential the current falls abruptly.
Highlights
Study of the electrooxidation of hydrogen is of great importance because of their application in oxygen/hydrogen fuel cells
A reversible hydrogen electrode, which is used as reference electrode, is placed in the lateral compartment connected to the central compartment by a Luggin capillary
Hydrogen is bubbled at a given partial pressure during the necessary time to obtain a constant H concentration in the electrolyte (30 min)
Summary
Study of the electrooxidation of hydrogen is of great importance because of their application in oxygen/hydrogen fuel cells. Oxygen electrochemical dissolution is much slower than that of the hydrogen. It provides the highest overpotential on the cell operation [1]. Atomic hydrogen diffuses into the metal and its surface concentration is very low [9]-[12]. On both metals potential assisted reconstruction surface occurs [13]. On the surfaces of both metals, the diffusion of the reagent controls the reaction in conditions of low hydrogen partial pressure [12] [14]
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