Amorphous Ru1-yCryO2/TiO2 nanotube composites were synthesized by loading different amount of Ru1-yCryO2 on TiO2 nanotubes via a reduction reaction of K2Cr2O7 with RuCl3 center dot nH(2)O at pH 8, followed by drying in air at 150 degrees C. Cyclic voltammetry and galvanostatic charge/discharge tests were applied to investigate the performance of the Ru1-yCryO2/TiO2 nanotube composite electrodes. For comparison, the performance of amorphous Ru1-yCryO2 was also studied. The results demonstrated that the three dimensional nanotube network of TiO2 offered a solid support structure for active materials Ru1-yCryO2, allowed the active material to be readily available for electrochemical reactions, and increased the utilization of active materials. A maximum specific capacitance 1272.5 F/g was obtained with the proper amount of Ru1-yCryO2 loaded on the TiO2 nanotubes. (c) 2006 Elsevier Ltd. All rights reserved.