Nanostructured Cobalt And Nickel Oxides Synthesis And Effect Of Doping

Abstract

Metal oxide nanomaterials and#8213;have been attracting significant attention in recent times because of their applications in the fields of energy and environment. Also, nanocomposites based on metal oxides are being explored for theirand#8214; electrochemical sensing features. The present thesis reports the synthesis of nanostructured cobalt oxide and nickel oxide via rapid, facile microwave method and cost-effective one-pot chemical reduction (co-precipitation) methodologies. Based on our hypothesis, the metal oxides have been doped with lithium to enhance their electrochemical and photochemical properties. The doped metal oxides have displayed extraordinary electrochemical characteristics suitable for battery applications. Further, the photocatalytic properties of the doped metal oxides have been analyzed for degradation of common organic dyes such as crystal violet, methyl violet 2B, alizarin red S, and also the hazardous pollutant pyrocatechol. It has been inferred that the dopant has a high influence on the size, morphology and structural constitution of the final product, which has been well-studied by various spectroscopic and microscopic analytical tools such as Fourier Transform Infrared spectroscopy (FT-IR), Powder X-ray Diffractometry (p-XRD), X-ray Photoelectron Spectroscopy (XPS), UV-Diffuse Reflectance Spectroscopy (UV-DRS) and Field Emission Scanning Electron Microscopy (FESEM). The electrochemical studies included cyclic voltammetry and electrochemical impedance measurements which indicate that the doping of Li into as-synthesized nanostructured metal oxides increases the peak currents of oxidation-reduction peaks and decreases the charge transfer resistance. Moreover, capacitance, charge/discharge capacity and cycling stability of the doped nanostructures are also noteworthy. In addition, the synthesized Li-doped nanostructures exhibit a low optical energy bandgap than pristine samples and are seen to play a crucial role in achieving the photocatalytic degradation of cationic organic dyes and pyrocatechol