Cu-doped ZnO nanoparticles on cellulose nanofibers for photocatalytic activity and antibacterial properties

This study presents a successful method for synthesizing ZnO pure and Cu-doped ZnO nanoparticles with different doping contents 0%, 0.1%, and 0.3% (mole fraction) by co-precipitation method. The morphological, compositional, and structural properties of the obtained materials were investigated using different characterization methods, such as X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared rays (FTIR) spectroscopy, scanning electron microscopy (SEM). The photocatalytic activity of these materials was evaluated by the degradation of methylene blue (MB) using the UV-Vis absorption spectrum. The results show that the Cu-doped ZnO nanoparticles exhibit a significant increase in photocatalytic performance compared to pristine ZnO nanoparticles, and the ZnO nanoparticles doped with 0.1% Cu show the best photocatalytic performance. The improvement in photocatalytic performance is attributed to the enhanced light adsorption in the UV-Vis range and the decrease of the recombination rate of the photoinduced electron-hole pair of the Cu-doped ZnO nanoparticles. The antibacterial activities of the Cu-doped ZnO-NPs were tested against typical bacteria of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) via the disk diffusion test. The zone of inhibition (ZOI) for Cu-doped ZnO-NPs was observed against S. Aureus and E. coli. The synthesized Cu-doped ZnO-NPs can thus be demonstrated as a potential nano antibiotic against multi-drug resistant bacteria.