This book provides a comprehensive overview of the current state-of-art in oxide nanostructures, carbon nanostructures and 2D materials fabrication. It covers mimicking of sensing mechanisms and applications in gas sensors. It focuses on gas sensors based on functional nanostructured materials, especially related to issues of sensitivity, selectivity, and temperature dependency for sensors. It covers synthesis, properties, and current gas sensing tools and discusses the necessity for miniaturized sensors. This book will be of use to senior undergraduate and graduate students, professionals, and researchers in the field of solid-state physics, materials science, surface science and chemical engineering.