High performance SERS on nanoporous gold substrates synthesized by chemical de-alloying a Au-based metallic glass

A Au20Cu48Ag7Pd5Si20 metallic glass precursor has been used to synthesize nanoporous gold by chemical de-alloying in a mixture of HNO3 and HF. Gold ligaments of size ranging from 45 to 100 nm were obtained as a function of HNO3 concentration, electrolyte temperature and de-alloying time. The as-prepared nanoporous gold exhibited strong surface enhanced Raman scattering (SERS) effect using 4,4'-bi-pyridine as probe molecule. For application in melamine sensing, the detection limit of 10(-6) M was achieved, which indicated that this biocompatible material has great potential as SERS active substrate. (C) 2017 Elsevier B.V. All rights reserved.