Freeze-Casting of Multifunctional Cellular 3D-Graphene/Ag Nanocomposites: Synergistically Affect Supercapacitor, Catalytic, and Antibacterial Properties

Abstract

Developments of new and highly effective multifunctional materials have been shown great interest in recent years. Herein, we report a simple, cost efficient, one-step, surfactant-free cellular 3D-graphene/Ag nanocomposite using the freeze-casting method and explore it further for supercapacitor, catalytic, and antibacterial applications. FE-SEM and HRTEM analyses of nano-composites revealed a 3D-cellular network structure having continuous micrometer size open pores with uniformly decorated Ag nanoparticles of an average size of 25 nm. An electrochemical study exhibited the highest specific capacitance at 845 Fg(-1) at 5 mV s(-1) and excellent cyclic retention similar to 97% even after 1000 cycles. Further, 3D-graphene/Ag nanocomposites are applied as catalyst to reduce methylene blue using NaBH4. A rate of reduction above 99% was attained for 3D-graphene/Ag (40%) nanocomposites, which is significantly higher than that of pristine 3D-graphene. The network like structure of the 3D-graphene/Ag nanocomposite filtered out 37% of the population from total bacterial strains. Also, the 3D-graphene/Ag nanocomposite killed almost 100% of the bacterial strains after 3 h of incubation due to a merging effect of Ag ions and 3D-graphene.