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

Abstract

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.