Aggregation-regulated bioreduction process of graphene oxide by Shewanella bacteria

Abstract

The bioreduction of graphene oxide (GO) using environmentally functional bacteria like Shewanella represents a green approach to produce reduced graphene oxide (rGO). This process differs from the chemical reduction that involves instantaneous molecular reactions. In bioreduction, the contact of bacterial cells and GO is considered the rate-limiting step. To reveal how the bacteria-GO integration regulates rGO production, the comparative experiments of GO and three Shewanella strains were carried out. FTIR,XPS, Raman spectroscopy and AFM were employed to characterize the reduction degree and the aggregation degree. The results showed that a spontaneous aggregation of GO and Shewanella into condensed entity occurred within 36 h. A positive linear correlation was established, linking three index of the aggregation potential, the bacterial reduction ability and the reduction degree (ID/IG) comprehensively.