Hydrothermal synthesis, characterization, electrochemical, and optical properties of 2D sheet-like CuO nanostructures

The present paper describes the structural, electrochemical, and optical properties of two-dimensional copper oxide nanosheets of length around 1 μm and thickness of 30 nm. The hydrothermal process was used to prepare the CuO nanosheets using copper nitrate trihydrate as an inorganic precursor and cetyltrimethylammonium bromide (CTAB), which acts as a structure-directing template. Serial physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), UV–visible diffuse reflectance spectra (DRS), and room-temperature photoluminescence (RTPL) were used to characterize the as-prepared samples. The structural results obtained from (XRD) confirm the monoclinic crystal structure CuO nanoelectrode, the phase purity, and the nanoscale character of the product. The CuO nanosheets have a higher band gap of 2.21 eV than bulk CuO, owing to the quantum confinement effect. The nanoscale characters could explain electrochemical performances, the nanosheet’s thickness, which can favor the easy electrons transfer and the high specific surface arising from the two-dimensional layers. The electrochemical properties of the CuO nanoelectrode showed reversible redox activity with charge–discharge cycling, which corresponded to the reversible lithium (Li) intercalation/deintercalation process. The results indicate that copper oxide nanosheet is promising for applications as an electrode material for a lithium-ion battery.