Influence of graphite feedstock on the characteristics of silver-decorated graphene oxide and antimicrobial property

Abstract

Graphite from different sources has significant influence on the properties of graphene oxide (GO) and reactivity of GO towards further modification with other nanoparticles. However, such effect has not yet been properly explored. This study aims to investigate the characteristics and antimicrobial property of GO decorated with silver nanoparticles (known as Ag-GO composite) where the GO is synthesized via modified Hummer’s method from various graphite feedstock, namely natural graphite flake (NGF), natural graphite powder (NGP), and synthetic graphite powder (SGP). The Ag-GO nanocomposite was then synthesized using chemical reduction methods. Antimicrobial properties of the Ag-GO were tested using the standard Kirby–Bauer antibiotic testing method with E. coli bacteria. Results showed that Ag-GO made from NGP has a smaller size and Ag nanoparticles (2 nm to 4 nm) were better distributed, and possessed better antimicrobial property. This phenomenon can be attributed to the higher number of functional groups on GO-NGP that can act as anchor sites for the nucleation of smaller-sized and well-dispersed Ag nanoparticles. It shows the significance of choosing the right graphite source where researchers can utilize to control the extent of decoration or coating of other nanoparticles on the synthesized GO to obtain the characteristics desired.