Browsing by Author "Obodo, R. M"

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    Electrode Materials for Energy Storage and Conversion
    (Tailor and Francis, 2022) Eze, C. N.; Obodo, R. M; Ezema, F. I; Kebede, M. A
    Alkaline earth stannates are rare earths and are crucial material systems evident of their attractive physical properties. They are ternary metal oxide semiconductors.They have both perovskite structures (BaSnO3, SrSnO3) and spinel structures(ZnSnO4).They are compounds of tin (Sn). Broadly, these compoundsexhibit elevated melting-points, elevated thermal stability, great thermal expansion coefficient, excellent chemical resistance, small thermal conductivity and great ionic conductivity which guarantee their possible applicacability in thermal barrier coating, hosts for luminescence centers, hosts for nuclear wastes, oxygen monitoring sensors, high-temperature catalysts, solar cells applicability and solid electrolytes in large temperature fuel cells. When these materials are produced as nanoparticles, the decreased particle size as well as enlarged specific surface area could result in diverse phase transition temperatures, improved catalytic activity, and enhanced processability. Commonly, these rare earth complex oxide nanomaterialscould be fabricated via conventional solid-state reactions, coprecipitation, sol-gel, hydrothermal, self-propagation techniques, etc.In the background of energy crisis, climate change, long-term supply and security, solar energy is a striking source. For these stannates to be better utilized in solar energy harvesting applications, they are better doped.The stannates considered here are SrSnO3, BaSnO3 and ZnSnO4.The doped stannates are used in various ways as stated above and equally as transparent conductors, light absorbers, photoanodes, etc. This is in relation to optical properties.The Optical properties, structural order and surface properties of these materials are considered. On doping, thesestannates maintain excellent transparency which makes them excellent materials as transparent conductor particularlyZnSnO4. They are found highly useful in photocatalysis and other areas.In solar energy harvesting, solar energy harvesting devices could have a better output when nanostructures like doped stannates are incorporated in them. Such advance is hopeful. It improves the power conversion efficiencies (PCE) of such devices by utilizing new nanostructures to update device structural designs. This is an applauded process.
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    Surface Modification and Functionalization of Ceramic Composites.
    (Elsevier, 2023) Okeke, I. S; Obodo, R. M; Eze, C. N.; Orji, M. P; Agwu, K. K; Ubachukwu, A. A; Ezema, F. I
    Materials with high dielectric constants are essential in the control and advancement of electronics and electrical power systems. The dielectric properties of materials majorly include dielectric constants (ꜫo) and loss tangent (tan ẟ), and for a material to be considered a very good dielectric material, it needs greater ꜫo, lower tan ẟ and reduced leakage current (J). Inorganic mixed transition oxides (MTMOS) ceramics composites have shown huge potential than the transition metal oxide because they constitute two or more metal elements with different expansion coefficients that give rise to synergistic effects. MTMOs ceramics composites are mostly found with spinel structure such as normal spinel structure (NSS) and inverse spinel structure (IVS). Several synthesis techniques have been used in formulation of MTMOs ceramic composites. Their dielectric properties have been modified considerately by altering its morphology, use of modifying agent, and high calcination temperatures. In this chapter, we summarized MTMOs major structure type synthesis technique that have been successfully used in preparation of MTMOs, the dielectric properties of MTMOs and basis of surface modification in MTMOs as well as its effect in the dielectric properties.