タングステン酸化物を電析させた白金上での酸素還元反応

抄録

Polymer electrolyte fuel cell (PEFC) systems have been under developing for residential cogeneration systems and electric vehicles. Energy conversion efficiency should increase and the cost should be reduced for the practical application. Therefore, activity of electrocatalysts based on platinum must be improved for the oxygen reduction reaction, because the efficiency loss of the overpotential by the oxygen reduction reaction (ORR) is the biggest among the efficiency losses.

Pt/WO_x electrocatalyst was known as anti-CO poison electrocatalyst for the oxidation of CO contain H₂ fuel, but the activity for the ORR has not been investigated. In this study, the activities of the anodic and the cathodic WO_x electroplated electrodes on Pt have been studied for the ORR. The Pt surface area of the anodic electroplated electrode seemed to increase during the potential scanning, and the apparent current density of the ORR increased. For the cathodic electroplated electrode, the ORR was observed from higher potential than that for Pt electrode, but the activity of the cathodic electroplated electrode was less than Pt electrode in the region lower than 0.9 V. These behaviors might be caused by the interaction between Pt and the WO_x. The anodic electroplated electrode with large real surface area was stable after potential scanning, but WO_x made by the cathodic electroplated electrode dissolved slowly.