Anchoring Core–Shell Cu@Cu₂O Nanoparticles to Two-Dimensional Carbon Nanosheets for Bacterial Disinfection

The unique physicochemical properties and relatively higher biosafety endow carbon-based nanomaterials with much worldwide attention. However, studies of the synthesis and functionalization of carbon nanosheets are still very limited, which largely impedes the development of carbon-based materials for antibacterial applications. In this work, carbon nanosheets decorated with core–shell Cu@Cu2O nanoparticles (Cu@Cu2O/C) were prepared by a facial hydrothermal method using copper d-gluconate. The in situ-generated carbon nanosheets feature a homogeneous size distribution with an average diameter of 3 μm and thickness of 5 nm. The particle size of Cu@Cu2O is mainly distributed between 10.5 and 13.5 nm. Particularly, these nanosheets could not only effectively anchor Cu@Cu2O core–shell structured nanoparticles but also bring more edge active sites, which could promote the generation of free radicals. The as-prepared Cu@Cu2O/C verified by varieties of characterizations were used as antibacterial samples to kill the Gram-negative bacterium Escherichia coli and the Gram-positive bacterium S. aureus with antibacterial efficiencies of up to 100 and 96.0%, respectively, within 12 min in the dark condition. A possible antibacterial mechanism of the •OH-dominated radical combined with the sharp edges of carbon nanosheets was confirmed by a series of control experiments. Overall, the present work provides a simple strategy to prepare carbon-based antibacterial agents, which sheds light on the understanding of the antibacterial mechanism of carbon-based nanomaterials.