ANODIC STABILITY OF ELECTRODEPOSITED RUTHENIUM - GALVANOSTATIC, THERMOGRAVIMETRIC AND X-RAY PHOTOELECTRON-SPECTROSCOPY STUDIES

The anodic stability of an electrodeposited ruthenium electrode was me asured by anodic galvanostatic polarization in 0.5 mol dm(-3) H2SO4 so lution. The role of water and adsorbed hydroxyl groups in electrode st ability was determined by means of thermogravimetric analysis. A conti nuous weight loss due to water removal and condensation of hydroxyl gr oups was detected between 120 and 430 degrees C. The loss of a hydrous component of the oxide layer was in direct correlation with the incre ase of the anodic stability. Between 430 and 480 degrees C a weight ga in was detected on the thermogravimetric curve. It was attributed to t he formation of the ruthenium oxide layer in a higher oxidative state. This finding was confirmed by X-ray photoelectron spectroscopy measur ements.