Gold Nanoparticles-Based Gas Sensors: A Comprehensive Review of Design, Mechanisms, and Applications.

Accurate detection of various gases is possible using gold nanoparticles (AuNPs) owing to their distinct physical, chemical, optical, and electronic properties. The review highlights the synergic properties of AuNPs, which allow them to detect many hazardous and greenhouse gases, such as NO₂, H₂S, CO, NH₃, volatile organic compounds (VOCs), etc. The role of AuNPs in enhancing the performance of gas sensors, with a particular focus on the detection of toxic and environmentally significant gases at trace levels, is also discussed. The novelty of this work lies in its comprehensive analysis of strategies to tune the sensitivity and selectivity of AuNPs-based gas sensors through controlled variation in particle size, shape, and surface functionalization. Furthermore, their hybridization with other nanomaterials like graphene, carbon nanotubes (CNTs), and metal oxides to enhance the performance is discussed in detail. Altogether, this article presents the role of AuNPs in enhancing the performance of gas-sensing devices. In addition, the application of AuNPs-based gas sensors in various fields of science and engineering is discussed briefly. Moreover, the challenges of AuNPs-based sensors from an industrial point of view are covered toward the end of this article.