Hierarchical nanostructures and their implications in pushing the boundaries of chemiresistive gas sensing

The escalating global air pollution crisis has propelled the interest in gas-sensing technology, leading to a surge in research dedicated to the development of highly accurate and targeted gas sensors. This review delves into the realm of smart gas sensors, focusing on various nanostructured materials utilized in gas sensings, such as metal oxide semiconductors (MOS), conducting polymers, carbon-based materials, transition metal dichalcogenides, and MXene-based materials. The paper comprehensively explores the fundamental chemiresistive gas sensing properties, analyzes the variables influencing sensitivity, selectivity, and stability, and examines the main components of gas sensors. Lastly, the review addresses the challenges faced and the future prospects of nanostructured materials-based gas sensors, providing a thorough overview of this dynamic field of research.