Electrocatalytic activity and anodic stability of electrodeposited ruthenium-rhodium coatings on titanium

The stabilizing effect of rhodium addition to ruthenium coatings on titaniu m under anodic polarization in acidic solutions is described. The addition of rhodium to the coating leads to both an overall improved stability of th e electrode, and an increase of the electrochemically active surface area. The service-life of a Rh-Ru coating polarized at 0.12 A cm(-2) in 0.5 mol d m(-3) sulphuric acid is improved by at least two orders of magnitude, while deterioration of the electroactive surface area never exceeds 30%. The rot ating ring-disc electrode measurements show the dissolution of the coating at potentials above the onset of the oxygen evolution reaction at 1.1 V ver sus SCE. (C) 1999 Kluwer Academic Publishers.