Synthesis and evaluation of copper–imidazole MOF nanostructures and its graphene nanocomposites by pulsed laser ablation method in liquid

Current work is the first report on synthesizing the copper–imidazole metal–organic framework (MOF) nanostructures and its graphene nanocomposites by pulsed laser ablation (PLA) process in liquid environment. 3 samples of copper–imidazole (Cu–I) MOF nanostructures were synthesized by irradiation of a copper metal target in dimethylformamide (DMF) solution containing 1.632, 0.921 and 0.347315 g imidazole ligand with the fundamental wavelength of a 7 ns pulsed Nd:YAG laser at 1064 nm. Then, 3 samples of graphene-MOF nanocomposites were made by the laser ablation of a graphite target in Cu–I MOF nanostructure suspension. The compatibility of the crystal structure and the presence of functional groups of synthesized nanostructures were confirmed based on XRD and FTIR analysis, respectively. Based on UV–Vis-NIR absorption, due to the smaller size of samples, a shorter wavelength was observed for the sample with lower ligand concentration, but there was not much difference after composition with graphene. Furthermore, field emission scanning electron microscope (FESEM), and transmission electron microscopy (TEM) were employed to study the morphology and size of synthesized the Cu–I MOF nanostructures and its nanocomposites. Images show that the number and size of nanomaterials increased with increasing the ligand concentration in the ablation liquid environment. The antibacterial activity of the samples was evaluated against Escherichia coli (E. coli) as a Gram-negative bacterium and Staphylococcus aureus (S. aureus) as a Gram-positive bacterium. Results confirm that Cu–I MOF nanostructures and its nanocomposite have high efficiency antibacterial properties and pulsed laser ablation is a capable method to produce such complicated nanostructures.