High-performance gas sensors based on nanostructured metal oxide semiconductors: Materials engineering and sensing mechanisms

The rapid rise in industrialization and urbanization has significantly increased air pollution, posing serious risks to human health and the environment. Although various gas detection methods have been developed, they often suffer from high costs, complex operation, and limited suitability for real-time monitoring. To address these challenges, extensive research has focused on developing efficient environmental sensors, progressing from theoretical studies to practical applications. Among these, Metal Oxide Semiconductor (MOS)-based gas sensors have emerged as a promising option owing to their cost-effectiveness, high sensitivity, selectivity, and reliable performance. This review provides a comprehensive overview of recent advancements in gas sensor technology, with particular emphasis on synthesis techniques, morphological modifications, and the gas-sensing mechanisms of MOS materials. Furthermore, it highlights the critical relationship between material properties and sensor performance and discusses future research directions aimed at advancing MOS-based gas sensing technologies.