A silver-grafted sponge as an effective surface-enhanced Raman scattering substrate

A silver film is in situ grafted on a melamine sponge via the silver mirror reaction. The porous structure of the sponge possesses an enlarged total SERS-active surface area without increasing the overall footprint of the SERS substrate. The Ag-grafted sponge exhibits high SERS activity toward Rhodamine 6G with a concentration down to 0.1 pM. Moreover, the sponge-based substrate also offers a good signal uniformity and reproducibility with a relative signal deviation down to 11.7% and 13.2%, respectively. Furthermore, the Ag-grafted sponge exhibits a limit of detection of 4.23   nM toward adenine and 1.88   nM toward thiram in the aqueous solution by a handheld portable Raman spectrometer. The inexpensive and simple Ag-grafted sponge can be used as an effective SERS substrate, which will find the potential application in field-deployable detection of organic pollutants in the aquatic environment.