Green electrochemical synthesis of ZnO-graphene composite nanopowder and its improved antimicrobial properties

Zinc oxide (ZnO) nanoparticles are used as an antimicrobial agent against microorganisms. Conventionally, ZnO is prepared via chemical routes that make use of toxic and expensive chemicals. Synthesis of ZnO nanoparticles via an eco-friendly method without using toxic chemicals and enhance their antimicrobial activity are of paramount value to industries. In this study, ZnO nanoparticles were synthesized using an efficient green electrochemical oxidation process. The as-synthesized ZnO nanoparticles were characterized using X-ray diffraction (XRD), High-Resolution Scanning Electron Microscope (HRSEM), Transmission Electron Microscope (TEM), and Raman spectroscopy. The XRD analysis confirmed the synthesis of ZnO nanoparticles with a crystallite size of 24.2 nm. Antimicrobial resistance of ZnO nanopowder was enhanced by manually mixing them with 5 wt% graphene. The graphene nanoplatelets were synthesized by green electrochemical exfoliation of graphite. Raman spectroscopy confirmed the synthesis of 3–5 layers of graphene with low defect concentrations. The graphene-ZnO composite nanopowder showed an increase in potency of 121.64 % against Staphylococcus aureus ( S. aureus ) bacterium compared to pristine ZnO nanoparticles. • ZnO nanoparticles were synthesized by a green electrochemical oxidation process. • Low defect graphene nanoplatelets were synthesized by exfoliation of graphite. • Potency of 5 % graphene-ZnO against S. Aureus bacterium is increased by 122 %.