ZnO nanomaterials with different shapes were synthesized, characterized and tested in the selective monitoring of low concentration of CO and NO₂ in air. ZnO nanoparticles (NPs) and nanofibers (NFs) were synthesized by a modified sol-gel method in supercritical conditions and electrospinning technique, respectively. CO and NO₂ sensing tests have demonstrated that the annealing temperature and shape of zinc oxide nanomaterials are the key factors in modulating the electrical and sensing properties. Specifically, ZnO NPs annealed at high temperature (700 °C) have been found sensitive to CO, while they displayed negligible response to NO₂. The opposite behavior has been registered for the one-dimensional ZnO NFs annealed at medium temperature (400 °C). Due to their adaptable sensitivity/selectivity characteristics, the developed sensors show promising applications in dual air quality control systems for closed ambient such as automotive cabin, parking garage and tunnels.

Ca-ZnO gas sensor exibited a good response and high selectivity toward NH₃ gas. Theses performances make the material an excellent candidate for monitoring ammonia gas at low concentrations.

In the race toward next-generation electronics and energy systems, ceramic nanocomposites have taken center stage due to their remarkable dielectric and ferroelectric functionalities. By pushing the boundaries of nanoscale engineering, recent studies have shown how microstructural control and interfacial design can unlock unprecedented levels of polarization, permittivity, and frequency stability. This review presents a critical and up-to-date synthesis of the last decade’s progress in ceramic-based nanocomposites, with a special focus on the structure property processing nexus. Diverse processing techniques ranging from conventional sintering to advanced spark plasma sintering and scalable wet-chemical methods are analyzed for their influence on phase purity, grain boundary behavior, and interfacial polarization. The review also explores breakthroughs in lead-free and eco-friendly systems, flexible ferroelectric nanocomposites, and high-k dielectrics suitable for miniaturized devices. By identifying both the scientific opportunities and persistent challenges in this rapidly evolving field, this work aims to guide future innovations in material design, device integration, and sustainable performance.