Synthesis of Ag NPs layer and its application as SERS substrate in the determination of p-phenylenediamine

An Ag nanoparticles (NPs) layer was synthesized on Ag sheet by alloying/electrochemical dealloying method: X-ray diffraction confirmed that the new Ag phase appeared after removing Ga from Ag-Ga alloy, and scanning electron microscopy examination showed that the prepared Ag layer had a NPS structure. The fine microstructure of silver resulted in significant SERS enhancement effect, while the NPs layer was used as the SERS substrate: when the prepared NPs layer was used as a SERS substrate to detect p-phenylenediamine (PPD), it exhibited a strong SERS peak at 1590 cm −1 . The result revealed that the intensity of SERS peaks was linear to the logarithm of PPD concentration in the range from 10 −16 mol L −1 to 10 −12 mol L −1 and the detection limit was 1.0 × 10 −17 mol L −1 .