KINETIC-STUDIES OF MOLECULAR-OXYGEN REDUCTION ON W0.013RU1.27SE THIN-FILMS CHEMICALLY SYNTHESIZED

The reaction of molecular oxygen reduction was investigated on an amor phous W0.013Ru1.27Se electrocatalyst compound in a 0.5 M H2SO4 solutio n. The electrocatalyst was synthesized by reacting transition metal ca rbonyl compounds with the elemental selenium in 1,2-dichlorobenzene (b .p. approximate to 180 degrees C), under refluxing conditions for 20 H s. The sample was characterized by Neutron Activation Analysis (NAA) a nd Scanning Electron Microscopy (SEM). The characterization of the ele ctrocatalyst indicated that the material, in a thin film form, consist ed of an amorphous phase with a distribution of nano-sized particles. Electrochemical studies were carried out by a using a Rotating Disc El ectrode (RDE) and a Rotating Ring-Disc Electrode (RRDE) techniques. Th e RDE and RRDE measurements indicated that the electrocatalyst is acti ve for molecular oxygen reduction in acid media with multi-electron ch arge transfer (n = 4e(-)), to form water. The reaction order and the h eterogeneous rate constants for a simple mechanism were evaluated. (C) 1997 Elsevier Science S.A.