Circumventing silver oxidation induced performance degradation of silver surface-enhanced Raman scattering substrates

Surface-enhanced Raman scattering (SERS) has been recognized as a promising sensing technique in biomedical/biosensing applications and analytical chemistry. Silver (Ag) nanostructures have the strongest SERS enhancement, but suffer from severe enhancement degradation induced by oxidation. Here, we introduce electrochemical reduction of silver oxide to produce Ag SERS substrates on request to partially circumvent the SERS enhancement degradation problem of Ag SERS substrates. Silver oxide nanostructures were first prepared in pure silver citrate aqueous solutions with controllable morphologies depending on the electrodeposition parameters. The transition process from silver oxide to Ag was investigated by density functional theory calculations. Based on the understanding of the transition mechanism, heating treatment, applying reducing agent, and electrochemical reduction were adopted to transform silver oxide to Ag. Notably, no organic agents were introduced neither in the electrodeposition of silver oxide nor electrochemical transformation of silver oxide to Ag. The electrochemical reduction strategy could produce Ag SERS substrates with a 'clean' surface with outstanding SERS performance in a simple as well as cost and time effective manner. Ag SERS substrates can be used in biomedical/biosensing fields. The approach through electrochemical reduction of silver oxide to generate Ag SERS substrate may push forward practical application process of Ag SERS substrates.