Amorphous RuO2 center dot xH(2)O was well coated on the benzenesulfonic functionalized multi-wall carbon nanotubes (f-MWCNTs) successfully via hydrothermal method. The decorated benzenesulfonic groups served as a bifunctional role both for solubilizing and dispersing MWCNTs into aqueous solution and for tethering Ru3+ precursor to facilitate the following uniform chemical deposition of RuO2 center dot xH(2)O. The electrochemical performance of RuO2/f-MWCNTs and utilization of RuO2 center dot xH(2)O were evidenced by cyclic voltammetry and galvanostatic charge/discharge tests. The specific capacitance of 1143 Fg(-1) for RuO2 center dot xH(2)O was obtained from RuO2/f-MWCNTs with 32 wt.% RuO2 center dot xH(2)O, which was much higher than that of just 798 Fg(-1) for the RuO2/p-MWCNTs. Even though the RuO2 center dot xH(2)O loading increases to 45 wt.%, the utilization of RuO2 center dot xH(2)O still possesses as high as 844.4 Fg(-1), indicating a good energy capacity in the case of high loading. (C) 2010 Elsevier Ltd. All rights reserved.