Breaking Down SERS Detection Limit: Engineering of a Nanoporous Platform for High Sensing and Technology
Articolo
Data di Pubblicazione:
2022
Abstract:
Abstract: In this study, nanoporous gold (NPG) was synthesized by free corrosion dealloying of
an amorphous precursor, Au20Cu48Ag7Pd5Si20 (at. %), in a mixture of nitric and hydrofluoric acid,
starting from amorphous melt-spun ribbons. NPG revealed a 3D nanoporous structure composed
of pores and multigrain ligaments of an average size of 60 nm. NPG was further anodized in
oxalic acid at 8 V vs. Ag/AgCl reference electrode to obtain a bimodal morphology composed of
ligaments disrupted in finer features. Both NPG and anodized samples (A-NPG) were found to
be mechanically stable to bending and active for surface-enhanced Raman scattering (SERS). SERS
activity of samples was investigated using 4,40-bipyridine as a probe molecule. A detection limit of
1016 Mwas found for both samples, but in A-NPG, the signal was strongly enhanced. The extremely
high enhancement obtained for A-NPG is attributed both to the small size of ligaments and crystals
of which they are made, as well as to the nanometric features resulting from anodization treatment.
Such a microstructure showed homogenous SERS response in terms of average enhancement all
across the surface, as demonstrated by mapping measurements. Furthermore, NPG and A-NPG were
tested as electrodes for electrocatalytic applications, showing good properties. The engineering steps
from the amorphous precursor to A-NPG led us to obtain a high-sensing platform, with extremely
low detection limit and intrinsic properties, that might significantly contribute to the cutting-edge
technology of the future.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
nanoporous gold; anodization; chemical dealloying; amorphous precursor; SERS; electrocatalyst
Elenco autori:
Scaglione, Federico; Battezzati, Livio; Rizzi, Paola
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