Facile synthesis of ultra-small ruthenium oxide nanoparticles anchored on reduced graphene oxide nanosheets for high-performance supercapacitors

Herein, we report a facile, low cost, and environmentally friendly approach to prepare reduced graphene oxide-ruthenium oxide hybrid (RGO-RuO 2 ) materials for supercapacitor electrode applications by in situ sol-gel deposition of RuO 2 nanoparticles on the surface of graphene oxide (GO), followed by a reduction of GO in a strong alkaline medium at a low temperature. The combination of the sol-gel route and the reduction of graphene oxide at low temperatures resulted in ultrafine, hydrated amorphous RuO 2 particles with sizes of only 1.0-2.0 nm, which uniformly decorated the surfaces of RGO sheets. The obtained RGO-RuO 2 supercapacitor exhibited excellent electrochemical capacitive performance in a 1 M H 2 SO 4 electrolyte with a specific capacitance more than 500 F g −1 at a current density of 1.0 A g −1 and high rate performance with the capacitance retention of 86% when the current density was increased 20 times, from 1.0 to 20.0 A g −1 in a two-electrode test cell configuration. The RGO-RuO 2 system also showed good cycling stability with a capacitance retention of 87% after 2000 cycles. The excellent capacitive properties of RGO-RuO 2 could be attributed to the uniform anchoring of ultra-small, hydrated amorphous RuO 2 nanoparticles on the surface of RGO sheets, resulting in synergistic effects between them. The developed approach represents an exciting direction for enhancing the device performance of the graphene-metal oxide composite supercapacitors and can be used for designing the next generation of energy storage devices. We report a facile and environment friendly approach to prepare ultra-small RuO 2 -RGO nanoparticle hybrid electrodes for high-performance supercapacitors.