Silver nanoparticles in gas sensing: A comprehensive review of synthesis, mechanisms, performance metrics, and emerging applications

Silver nanoparticles (AgNPs) possess unique physical, chemical, and antibacterial qualities, making them highly versatile and widely used in a variety of products. These nanoparticles are utilized across various fields, including electronics, biosensing, textiles, cosmetics, sunscreens, and medical devices. Due to their unique combination of high electrical conductivity, strong surface plasmon resonance (SPR), and efficient electron transfer properties, AgNPs have garnered significant attention for sensing applications. This review provides a comprehensive overview of AgNP-based gas sensors, covering synthesis methods and their influence on nanoparticle size, shape, and stability. The integration of AgNPs with supporting materials, such as metal oxides, reduced graphene oxide, and polymers, is also discussed, highlighting improvements in sensitivity, selectivity, and operational stability. Major sensing mechanisms are explained in relation to the detection of ammonia, hydrogen sulfide, ethylene, and other relevant gases. These insights aim to guide the development of advanced AgNP-based gas sensors with enhanced performance for environmental and biomedical applications.