期刊
NANOMATERIALS
卷 12, 期 10, 页码 -出版社
MDPI
DOI: 10.3390/nano12101737
关键词
nanoporous gold; anodization; chemical dealloying; amorphous precursor; SERS; electrocatalyst
类别
资金
- European Commission, Marie Curie Actions-Initial Training Networks (ITN) [607080 FP7-PEOPLE-2013-ITN]
- BINGO Project [Torino_call2014_L2_146]
- Fondazione Compagnia di San Paolo Italy
Nanoporous gold (NPG) was synthesized through free corrosion dealloying and further anodization treatment to obtain a bimodal morphology. The resulting samples showed mechanical stability, active surface-enhanced Raman scattering (SERS) response, and good electrocatalytic properties.
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 4,4 '-bipyridine as a probe molecule. A detection limit of 10(-16) M was 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.
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