Abstract
A simple method with a high product yield (about 99%), i.e., chemical oxidation of RuCl 3 ·xH 2 O with H 2 O 2 , is successfully developed for the synthesis of hydrous ruthenium oxide (denoted as RuO x ·nH 2 O). The main product of this chemical synthesis is RuO 2 ·nH 2 O with a significant amount of RuO 3 from the X-ray photoelectron spectroscopy results. All RuO x ·nH 2 O powders without and with annealing in air between ISO and 400°C for 2 h show an amorphous structure from the X-ray diffraction and electron diffraction analysis. The annealed RuO x ·nH 2 O with the amorphous structure exhibits the ideal capacitive performance (i.e., highly electrochemical reversibility, high-power property, and excellent stability). The specific capacitance of annealed RuO x ·nH 2 O, measured at 25 mV/s from a RuO x ·nH 2 O-coated graphite electrode (denoted as RuO x /G), is ≥500 F/g when the annealing temperature is between 200 and 350°C. © 2004 The Electrochemical Society. All rights reserved.