Hydrothermal synthesis and electrochemical capacitance of RuO2·xH2O loaded on benzenesulfonic functionalized MWCNTs

Amorphous RuO2·xH2O 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·xH2O. The electrochemical performance of RuO2/f-MWCNTs and utilization of RuO2·xH2O were evidenced by cyclic voltammetry and galvanostatic charge/discharge tests. The specific capacitance of 1143 Fg−1 for RuO2·xH2O was obtained from RuO2/f-MWCNTs with 32 wt.% RuO2·xH2O, which was much higher than that of just 798 Fg−1 for the RuO2/p-MWCNTs. Even though the RuO2·xH2O loading increases to 45 wt.%, the utilization of RuO2·xH2O still possesses as high as 844.4 Fg−1, indicating a good energy capacity in the case of high loading.