Ceria (CeO2) is an important material mainly for microelectronic and fuel-cell applications due to having high dielectric constant and good catalytic properties. The first principle and experimental investigations were carried out to study the effect of Zn incorporation on the electronic and optical response of CeO2. Density of states spectra depict the prominent hybridization of Ce-f and O-p states while band structure reveals the decrease in bandgap with the incorporation of metallic Zn content in ceria structure. X-ray diffraction analysis detects the crystalline traces of CeO2 in pristine and doped thin films. Field emission scanning electron micrographs and energy dispersive X-ray spectra of synthesized thin films present the uniform distribution of grains with clear grain boundaries with expected elemental contents. The experimental observations comparatively follow the trend of simulation curves. Optical studies demonstrate a clear increment in absorption coefficient, optical conductivity, and real epsilon with Zn incorporation in ceria which makes these compositions favorable for applications in modern electronic devices.

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Because of the versatile chemical, physical, and electrical properties, graphene as well as its nanocomposites are regarded as the backbone of engineering and scientific innovation. Different physical and chemical methods are used to create sustainable carbon materials. Furthermore, fabrication methods are employed in order to produce the composites, which are of constituents with desirable properties. Because of their biocompatibility, graphene nanomaterials have enormous potential for improving biology and drug delivery. The proposed chapter provides a variety of fabrication methods for sustainable graphene composites and highlights various applications of graphene. Furthermore, graphene nanocomposites are promising multifunctional materials with improved tensile strength and elastic modulus. Despite some challenges and the fact that carbon nanotube/polymer composites are sometimes better in some specific performance, graphene nanocomposites may have a wide range of potential applications due to their outstanding properties and the low cost of graphene. Because these graphene composites have a controllable porous structure, a large surface area, high conductivity, high temperature stability, excellent anti-corrosion properties, and composite compatibility, they can be used in energy storage as electrocatalysts, electro-conductive additives, intercalation hosts, and an ideal substrate for active materials. Meanwhile, the chapter summaries the graphene nanocomposites requirements for technological innovation and scientific applied research.