Biological reduction of graphene oxide using Citrus sinensis L. extract and its nano-structural photocatalytic - antibacterial performances

Abstract

Reduced graphene oxide (rGO) plays a major role for the potential material fabrication attributable to its excellent electrical, thermal, optical, and mechanical properties. A facile cost-effective green reduction has been approached in this work for the reduction of graphene oxide (GO). The extract of Citrus sinensis L. fruit was employed as bio-reductant to obtain rGO. Initially, the graphene oxide, used in this work, was synthesised through the oxidation of graphite using modified Hummer’s method. Surface and structural properties of synthesised rGO were characterised by XRD, UV–visible, FTIR, SEM-EDAX, and AFM studies. From XRD results, the size of GO and rGO nanoparticles was found to be 3.7 nm and 2.4 nm respectively, the interspatial distance of rGO layers obtained was 0.34 nm, and it can act as an efficient photocatalyst. From the UV–visible spectral studies, the band gaps of rGO and GO were found as 5.22 eV and 4.70 eV, respectively. The functional group representations from FTIR spectra confirm the strong reduction of GO using Citrus sinensis L. extract. The SEM and AFM images provided clear even flake appearance of rGO particles. Photoluminescence studies explored good photoemissive nature of synthesised GO and rGO. The photocatalytic activity of rGO was tested against the Sunlight exposed methylene blue (MB) dye and found superior results of 98% degradation up to 100 ppm MB dye. While concerning its antibacterial response, it can strongly act against Staphylococcus aureus bacterium than the standard drug gentamicin.