Recent trends in gas sensing material development highlight a shift toward low-dimensional and nanostructured materials that offer enhanced surface-to-volume ratios and tailored active sites. As the gas sensing materials play a pivotal role in the advancement of environmental monitoring, industrial safety, medical diagnostics, and homeland security. This chapter provides a comprehensive overview of the development and synthesis methodologies of gas sensing materials, ranging from metal oxide semiconductors, conducting polymers, carbon-based nanostructures to emerging 2D materials including metal–organic frameworks (MOFs). Emphasis is placed on how synthesis techniques including sol–gel processes, hydrothermal methods, chemical vapor deposition, and electrospinning directly influence the morphological, structural, and surface properties that determine sensor performance. The chapter further explores the relationship between material properties and gas detection parameters such as sensitivity, selectivity, response time, and stability. Despite notable progress, several research gaps remain unaddressed. These include limited selectivity under real-world multispecies conditions, poor long-term stability, insufficient understanding of gas-material interaction mechanisms at the atomic level, and challenges in scalable and green synthesis. Moreover, the integration of gas sensing materials into flexible, wearable, or IoT-enabled devices presents new material compatibility and miniaturization challenges. This chapter concludes by outlining promising research directions, such as operando spectroscopy for mechanistic studies, AI-guided material discovery, and the development of multifunctional and self-healing sensing systems. The chapter concludes by outlining future research directions that could bridge these gaps, including machine learning-assisted material discovery, hybrid material architectures, and operando characterization techniques to gain deeper mechanistic insights.
