Au&Co core-shell nanoparticles capped with porous carbon: High performance materials for supercapacitor applications

• The Au&Co@C composite material with core-shell nanostructures was synthesized.
• Au&Co bimetal nanoparticles possess excellent crystallinity.
• The specific capacitance of the composites is up to 568 F g−1 at 1 A g−1.
• The specific capacitance retention rate is 97.1% even at 20 A g−1 after 1000 cycles.

In this article we synthesized the gold and cobalt bimetal-porous carbon (Au&Co@C) composite material in core-shell structure with Au@ZIF-67 (Co(MeIM)2, MeIM=2-methylimidazole) as a precursor by a thermal decomposition method. The gold and cobalt bimetal nanoparticles (Au&Co) obtained at about 15 nm in size were anchored on carbon homogeneously. The specific capacitance of the composite material was up to 568  F g−1 at a current density of 1 A g−1 in 1.0 M KOH electrolyte. More significantly, the specific capacitance retention rate was 97.1% at a current density of 20 A g−1 after 1000 cycles. All the results indicated that Au&Co@C composite material was a promising one for supercapacitors.