Synthesis and Characterization of Pure TiO₂ and TiO₂-Doped Bi₂O₃ Nanocomposites for Electrochemical Applications

To remove toxic wastes from water bodies by using a photocatalyst is the objective of this paper. Chemically, pure TiO₂ and TiO₂-doped Bi₂O₃ nanoparticles are synthesized using the low temperature hydrothermal method. The properties of the synthesized nanoparticles were studied using various characterization methods. In addition to powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and Fourier transform infrared (FTIR) analyses, we studied the structural and surface morphology of the nanoparticles. By analyzing those data, we can determine the average crystallite size, strain, crystallinity, the molecular composition, the grain size of the nanoparticles, the structure, shape, functional groups, and types of bonds between them. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyses were used for electrochemical studies. Based on these data, a study was conducted on charge transfer and specific capacitance. Photoluminescence (PL) and ultra-visible absorbance (UV-vis) spectra were used to determine the optical properties. Based on these spectra, it is possible to determine the optical bandgap of the particles and their potential as photocatalysts. Under a visible light radiation source, pure TiO₂ and TiO₂-doped Bi₂O₃ nanocomposites were used in the photocatalytic degradation of malachite green (MG) and Rhodamine-B (RhB) dyes. By studying the observations, we were able to determine the degradation efficiency, as well as the rate constant. Results showed that the TiO₂-doped Bi₂O₃ nanocomposites showed an increase in degradation efficiency of ~0.8% for RhB dye and ~27.7% for MG dye when compared to pure TiO₂ nanoparticles.