Peeyush Phogat, Shreya, Ranjana Jha, Sukhvir Singh, Netaji Subhas University of Technology, New Delhi, India
Two-dimensional (2D) nickel oxide (NiO) was synthesized using carbon as templates in a single step hydrothermal route. X-ray diffraction studies revealed the formation of a single phase NiO. Crystallite size and strain in the as synthesized material were calculated using the Williamson-Hall method and Size-Strain plot. UV-Vis spectroscopy investigations provided insight into the absorption region and optical band gap of NiO, including refractive index analysis. The optical absorption indicated that the material absorbs in both UV and part of visible region, with a reduced band gap of 1.9 eV. Microstructural analysis of NiO was carried out by using high resolution transmission electron microscope (HRTEM) which confirmed the presence of nanosheets. The selected area electron diffraction pattern (SAEDP) of the corresponding area revealed the polycrystalline nature of the as synthesized NiO, with fine crystallites oriented along (111) and (220) planes. Morphological analysis was performed using field emission scanning electron microscopy (FESEM), revealing the presence of 2D nano-sheets. Elemental compositional analysis was carried by using energy-dispersive X-ray spectroscopy (EDS) as an attachment of FESEM and TEM, which showed the presence of nickel and oxygen only. Nyquist plot and cyclic voltammetry depicts the capacitive behaviour, suggesting the material’s suitability for capacitor/supercapacitor applications.