Surface-enhanced Raman scattering on nanoporous Au

Abstract

Colloidal solutions of metal nanoparticles are currently among the most studied substrates for sensors based on surface-enhanced Raman scattering (SERS). However, such substrates often suffer from not being cost-effective, reusable, or stable. Here, we develop nanoporous Au as a highly active, tunable, stable, biocompatible, and reusable SERS substrate. Nanoporous Au is prepared by a facile process of free corrosion of AgAu alloys followed by annealing. Results show that nanofoams with average pore widths of ∼250nm exhibit the largest SERS signal for 632.8nm excitation. This is attributed to the electromagnetic SERS enhancement mechanism with additional field localization within pores.

Thermal properties of nanoporous gold

“…The lowest temperatures were 133 K (bulk Au), 163 K (NPG), and 183 K (bulk Ag). The rest of the temperatures were the same for all samples studied: 298, 393, 488, 583 and 673 K. As the structure of NPG is reported to coarsen when annealed at temperatures above 423-473 K, 4 the last 2 temperature points were used for evaluating coarsening effects on EXAFS data.…”

“…Nanoporous gold (NPG) received much attention during the last decade as an unsupported catalytic system [1][2][3] and as an attractive material in the field of sensors, 4 actuators and optics. 5 Their enhanced catalytic properties for CO oxidation are often attributed, much like in nanoparticle catalysts, to the presence of undercoordinated Au atoms.…”

Deformation Behavior of Nanoporous Metals

“…Nanoporous Au is ideally suited to study length scale effects in nanoporous metal foams due to its unique annealing behavior: The length scale of both pores and ligaments can easily be adjusted by a simple thermal treatment in ambient over a wide range from 3 nm to the micron length scale. [18][19][20] Most notably, the material rearrangement during annealing does not affect the relative density or relative geometry of the material (ligament connectivity or ligament, pore, and sample shape). [18,21] An example of such an annealing experiment is shown in Figure 2.…”

Preparation of Nanoporous Palladium by Dealloying: Anodic Polarization Behaviors of Pd-M (M=Fe, Co, Ni) Alloys

“…1,2) Recent research studies on dealloying mostly focus on nanoporous gold fabricated by dealloying Au-Ag alloy. [1][2][3][4][5][6][7][8] The fabricated nanoporous Au offers interesting properties, such as the dependence of mechanical strength on ligament size, 3,4) surface-enhanced Raman spectroscopic properties, 5) electrocatalytic properties, 6) piezoelectricity, 7) electrical resistance variation due to adsorbates 8) and so on. Other metals can also be made nanoporous through dealloying; for example, Pugh et al 9) and Liu et al 10) fabricated nanoporous platinum by dealloying Pt-Cu alloy.…”