Ruthenium oxide-based nanocomposites with high specific surface area and improved capacitance as a supercapacitor

A solvothermal strategy and a mutual oxidation–reduction approach are used to fabricate ruthenium oxide (RuO2)-based nanocomposites, including RuO2 and RuO2–gold (Au) nanoparticles supported on commercial carbon supports (RuO2/C and RuO2–Au/C nanocomposites). The novelty of this work lies in the synthetic approaches, which are based on a thermal decomposition of metal complexes formed by RuCl3 and dodecylamine at room temperature (for RuO2/C) and the mutual oxidation–reduction phenomenon between RuCl3 and HAuCl4 at elevated temperature (for RuO2–Au/C) in the presence of carbon supports. In particular, the as-prepared RuO2/C and RuO2–Au/C nanocomposites for supercapacitors adopting the H2SO4 electrolyte exhibit high specific capacitances of 537.7 F g−1 and 558.2 F g−1, respectively, at a current density of 50 mA g−1. The specific capacitance reaches 350.1 F g−1 for the RuO2/C nanocomposites and 478.5 F g−1 for RuO2–Au/C nanocomposites at a current density of 200 mA g−1 with good cycling stability. The comparison of the electrochemical measurements of RuO2/C and RuO2–Au/C nanocomposites demonstrates that the presence of Au in the nanocomposites is favorable for the enhancement in capacitive behavior of RuO2.