Carbon/carbon nanotube-supported RuO2 nanoparticles with a hollow interior as excellent electrode materials for supercapacitors

Tailoring the internal structure of nanomaterials is an effective way to enhance their performance for a given application. Herein, a core–shell templated approach is demonstrated to fabricate carbon or carbon nanotube-supported hollow structured RuO 2 nanoparticles as excellent electrode materials for supercapacitors . This strategy involves the synthesis of core–shell Ag–Ru nanoparticles, and subsequent loading on carbon or carbon nanotube support. Then the Ag component is removed from the core region using saturated aqueous Na 2 S solution to generate hollow structured Ru nanoparticles on carbon or carbon nanotube support, which are then converted into RuO 2 with intact hollow structure by thermal treatment in air. In particular, the as-prepared carbon or carbon nanotube-supported hollow RuO 2 nanoparticles for a supercapacitor adopting the H 2 SO 4 electrolyte exhibit high specific capacitances of 817.1 and 819.9   F   g −1 , respectively, at a current density of 0.2   A   g −1 . The specific capacitances for hRuO 2 /C, hRuO 2 /CNT nanocomposites were maintained at 805.8 and 770.2   F   g −1 , respectively, at current density of 0.5   A   g −1 with good cycle stability. The comparison in electrochemical performance between the hollow structured RuO 2 and their core–shell counterparts for a capacitor manifests that the preparation of RuO 2 nanoparticles with hollow interiors is favorable for the enhancement in their capacitive behavior.