In-situ grafting of Au and Cu nanoparticles over graphitic carbon nitride sheets and unveiling its superior supercapacitive performance as a hybrid composite electrode material

Abstract

In this article, a bimetallic hybrid composite of Au and Cu nanoparticles over graphitic carbon nitride has been reported as supercapacitor electrode material. The bimetallic Au-Cu/g-C3N4 hybrid was synthesized using facile one-phase impregnation of Au and Cu nanoparticles in holey g-C3N4 sheets. The as-synthesized materials were systematically characterized to assess structural, morphological, electronic, and thermal properties. The electrochemical tests revealed that the Au-Cu/g-C3N4 hybrid uncovers a superior specific capacitance of 506.25 F/g at 1.25 A/g current density amiable cycle stability with 76.1% capacitance retention at 5 A/g current density after 5000 cycles and excellent rate capability. Our designed asymmetric supercapacitor device based on Au-Cu/g-C3N4 hybrid unveils specific energy of 59.3 Wh/kg at a specific power of 2.49 kW/kg. The substantial enhancement in supercapacitor performance of Au-Cu/g-C3N4 compared to pristine g-C3N4, Au/g-C3N4, and Cu/g-C3N4 is attributed to synergy between Au, Cu nanoparticles, and semiconductor g-C3N4 surface. In hybrid electrode material, the mass ratio of components plays a vital role synergistic supercapacitive effect.