RuO2-TiO2 coated titanium anodes obtained by the sol-gel procedure and their electrochemical behaviour in the chlorine evolution reaction

TiO2 and RuO2 sols were obtained from RuCl3 and TiCl3 aqueous solutions by condensation and forced hydrolysis at elevated temperature. The Ti supporte d coatings were obtained by the sol-gel method using a sol mixture in which the metal content was Ru(40%)-Ti(60%). The crystal structure of the solid phase of the sols and their mixtures was examined by S-ray diffraction. The surface and morphology of the coatings were characterized by scanning elec tron microscopy and scanning tunneling microscopy. Polarization measurement s and cyclic voltammetry were used to obtain information about the electroc hemical properties of the obtained anodes. An accelerated corrosion test wa s applied to quantify the anode stability for the chlorine evolution reacti on. A stability comparison of the anodes shows a considerably higher lifeti me for sol-gel coated anodes than for those obtained by the usual thermal d ecomposition method. (C) 1999 Elsevier Science B.V. All rights reserved.