Nanoporous silver fabricated with pretreated Ag–Al alloy toward surface enhanced Raman sensing

Abstract Nanoporous silver (NPS), characterized by its three-dimensional bi-continuous interpenetrating ligament channel structure, is a good candidate for surface enhanced Raman scattering (SERS), attributed to its exceptional surface-to-volume ratio and significant SERS enhancement capabilities. Here, we have successfully fabricated NPS through the dealloying of α-terpineol (α-TPN) coated Ag₅₅Al₄₅ alloy. The resulting α-NPS exhibits uniform ligaments and nanopore sizes, maintaining high SERS performance even after being exposed to air for more than one month. The pretreatment of precusor alloy with α-TPN is crucial not only for the formation of nanoporous structure but also for ensuring the long term stability of α-NPS. Specifically, α-TPN functions as a surfactant, facilitating atomic diffusion to achieve a superior interconnected NPS. Furthermore, during the dealloying process, the carbonization of α-TPN serves as a protective layer, effectively inhibiting the oxidation of silver.