Hydrothermal synthesis of sheaf-like CuO via ionic liquids

Sheaf-like CuO consisting of nanoplatelets were synthesized by a hydrothermal method at 100 °C from Cu(NO3)2·3H2O and NaOH in the presence of an ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM]BF4). The XRD indicated the high crystal quality of CuO with monoclinic crystal structure. FESEM and TEM images showed the nanoplatelets with lengths of 4–5 μm, thickness of 65–80 nm and end angle of 60°. FTIR spectra and TG/DSC curves confirmed the adsorption of [BMIM]BF4 on the surface of CuO. The morphology of CuO could be controlled by the feeding manner of [BMIM]BF4. It was demonstrated that [BMIM]BF4 served as a cosolvent and modifiers in the reaction system. Further, the possible growth mechanism of the sheaf-like CuO was proposed.