RuO2-based electrodes are generally known to be unstable for 02 evolution. In this paper, a stable type of RuO2-based electrode, Ti/RuO2-Sb2O5-SnO2, is demonstrated for O-2 evolution. In the ternary oxide coating, RuO2 serves as the catalyst, SnO2 as the dispersing agent, and Sb2O5 as the dopant. The accelerated life test showed that the Ti/RuO2-Sb2O5-SnO2 electrode containing 12.2 molar percent of RuO2 nominally in the coating had a service life of 307 It in 3 M H2SO4 solution under a current density of 0.5 A cm(-2) at 25 degrees C, which is more than 15 times longer than other types of RuO2-based electrodes. Instrumental analysis indicated that RuO2-Sb2O5-SnO2 was a solid solution with a compact structure, which contributed to the stable nature of the electrode. (c) 2005 Elsevier Ltd. All rights reserved.