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 nanocomposites 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 ∼97% even after 1000 cycles. Further, 3D-graphene/Ag nanocomposites are applied as catalyst to reduce methylene blue using NaBH 4 . 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.

High performance fully paper‐based all‐solid‐state supercapacitor fabricated by a papermaking process with silver nanoparticles and reduced graphene oxide‐modified pulp fibers

“…There are mainly C 1s, O 1s, and Ag 3d peaks in the figure. The high‐resolution Ag 3d XPS spectrum of Ag‐Cell/RGO‐Cell paper (Figure S4) indicated the stability of Ag NPs during the reduction of GO 35‐38 . It can be clearly seen that the relative height of the O 1s peak is greatly reduced after the reduction of GO with vitamin C 49,50 .…”

“…Because of their outstanding conductivity, Ag nanomaterials, such as silver nanoparticles (Ag NPs) and silver nanowires (Ag NWs), are often incorporated into graphene‐based electrode to enhance their electrical conductivity and thus electrochemical performance 34‐39 . Compared with the Ag NPs, Ag NWs with a higher length‐diameter ratio have a lower percolation threshold, indicating a lower dosage in composite.…”

Hybridized Graphene for Supercapacitors: Beyond the Limitation of Pure Graphene

“…In 2018, Sahoo et al. [ 89 ] proposed an one‐step, simple and surfactant‐free freeze‐casting method to prepare cellular 3D‐graphene/Ag nanocomposite as SC electrodes. The covalent linkage between graphene sp 2 carbon and AgNPs (Ag‐O‐C) and the strong interaction between the AgNPs and the graphene matrix ensured the fast and efficient charge transportation and storage from fast faradic process from the chemical redox reaction of AgNPs.…”

Directional Freeze‐Casting: A Bioinspired Method to Assemble Multifunctional Aligned Porous Structures for Advanced Applications

“…Sahoo et al [114] has fabricated a 3D open porous carbon-based porous structure as a highly efficient supercapacitor. Considering chemical stability and high electrical conductivity of Ag as a noble metal, they synthesized the Ag nanoparticles decorated 3D rGO via the freeze-casting method (Figure 17).…”

“…b) Capacitive retention values of 3D‐graphene/Ag (40%) at 100 mV s −1 scan rate for 1000 cycles (inset shows the corresponding cyclic voltammetry curves) and c) demonstration of two fabricated ASC devices in series that light up the commercial red light‐emitting diode (LED). Reprinted with permission . Copyright 2018, American Chemical Society.…”