Analysis of the Relation between Oxidation State and ORR Activity of Pt by Linear Sweep Voltammetry

摘要

The catalytic activity of the Pt and Pt-based cathode electrocatalysts, on which the oxygen reduction reaction (ORR) occurs, has been one of the most extensively studied subjects on proton exchange membrane fuel cells (PEMFC).(l-4) The oxygen-containing species on platinum play important roles for the catalytic activity; the ORR requires oxygen adsorption on the surface, although strongly-bonded oxides block the active sites. It is known that the electrocatalytic activity of platinum for oxygen reduction reaction (ORR) decreases with increase in the surface oxide (1). The quantitative relation between them, however, has not been elucidated. In this study, platinum oxide grown by potential cycles or hold was analyzed using linear sweep voltammetry (LSV), and its influence on the oxygen reduction reaction (ORR) was investigated using a carbon-supported Pt nano-particle catalyst (Pt/C).