Gas sensors are of a great interest for applications including toxic or explosive gases detection in both in-house and industrial environments, air quality monitoring, medical diagnostics, or control of food/cosmetic properties. In the area of semiconductor metal oxides (SMOs)-based sensors, a lot of effort has been devoted to improve the sensing characteristics. In this work, we report on a general methodology for improving the selectivity of SMOx nanowires sensors, based on the coverage of ZnO nanowires with a thin ZIF-8 molecular sieve membrane. The optimized ZnO@ZIF-8-based nanocomposite sensor shows markedly selective response to H2 in comparison with the pristine ZnO nanowires sensor, while showing the negligible sensing response to C7H8 and C6H6. This original MOF-membrane encapsulation strategy applied to nanowires sensor architecture pave the way for other complex 3D architectures and various types of applications requiring either gas or ion selectivity, such as biosensors, photo(catalysts), and electrodes.

Nanofiber unique characteristics and potential applications offer innovative strategies and opportunities for sustainable energy production, and for creative solutions to biomedical, healthcare, and environmental problems. This review summarizes the history and development of nanofiber technology, their unique properties, fabrication techniques (using spinning and nonspinning approaches), and emerging applications in energy harvesting and storage, environmental protection and improvement, and biomedical technology and healthcare.Nanofibers are currently used as electrode and membrane materials for batteries, supercapacitors, fuel cells, and solar cells. Nanofiber membranes are also successfully used for ultra-high air filtration, wastewater treatment, water purification, and blood purification at low pressure. This review will describe the different types of nanostructured fibers (e.g., solid, mesoporous, hollow, core-shell nanofibers) fabricated from natural and synthetic polymers, metal and metal oxides, carbon-based, inorganic-organic hybrid nanofibers and their potential applications. Moreover, it will highlight the current and future research needs in nanofiber-based materials to improve and broaden their applications and commercialization.