Gas sensors play a pivotal role in monitoring air quality, ensuring public safety, and detecting trace gases in various industrial sectors. The demand for highly efficient, sensitive, selective, reliable, low-power-consumption, and cost-effective gas sensors is paramount. While traditional metal oxide semiconductor (MOS) materials-based gas sensors have been widely employed in various applications, their selectivity and power consumption remain unsatisfactory. Graphene, as the earliest discovered two-dimensional (2D) material, has gained significant attention for gas sensing application owing to its large specific surface area and high charge carrier mobility. In the past decade, a number of novel 2D nanomaterials, including transition metal dichalcogenides (TMDs, e.g., MoS2), Mxenes (e.g., Ti3C2), and metal-organic frameworks (MOFs), have emerged as promising alternatives. In addition to a large surface-to-volume ratio akin to graphene, these layered materials exhibit semiconducting properties with an adjustable bandgap, offering potential for enhancing gas sensing performance. In this talk, the application of 2D materials in gas sensing will be presented and their working mechanisms will be discussed. Furthermore, the role of machine learning techniques in enhancing the intelligence of gas sensors to identify various gases and VOCs will be demonstrated. Lastly, the emerging applications of intelligent gas sensors will be presented.