{331}-Faceted trisoctahedral gold nanocrystals: synthesis, superior electrocatalytic performance and highly efficient SERS activity

Abstract

We investigate the effect of gold (Au) seeds prepared in cetyltrimethylammonium chloride solution (CTAC-Au seeds) on the index facets of trisoctahedral gold nanocrystals (TOH Au NCs). We demonstrate that monodisperse {331}-faceted TOH Au NCs with controllable sizes (from 60 to 255 nm) can be successfully prepared in high yield by using 3.0 nm CTAC-Au seeds or as-prepared 70 nm TOH Au NCs as seeds. We find that the electrocatalytic performance on methanol oxidation and surface enhancement Raman spectroscopy (SERS) activity of {331}-faceted TOH Au NCs is size-dependent. In comparison with well-known nanoporous gold (0.088 mA cm(-2)), {331}-faceted TOH Au NCs with sizes of 110 nm exhibit fairly high catalytic activity (0.178 mA cm(-2)) on methanol oxidation (1.0 M) in alkaline media due to the presence of increasing density of atomic steps, ledges, and kinks on the NC surfaces. Their current density is reduced by less than 7% after 500 cycling tests. {331}-Faceted TOH Au NCs with sizes of 175 nm exhibit the highest SERS activity for 4-aminothiophenol (4-ATP) molecules. The enhancement factors of a1 modes of 4-ATP molecules can reach the order of 10(9) when the 4-ATP concentration is 3 × 10(-6) M. Moreover, Raman signals (ag modes) of 4,4'-dimercaptoazobenzene (DMAB) molecules on TOH Au NCs are stronger than those on spherical Au NCs of comparable size due to the enhanced laser-induced transformation of 4-ATP molecules by high-index {331}-facets during SERS measurement. Furthermore, the SERS intensities of 4-methylbenzenethiol (4-MTP) molecules on TOH Au NCs are also higher than those on spherical Au NCs of comparable size due to sharp extremities.

The alloying effect and AgCl-directing growth for synthesizing a trimetallic nanoring with improved SERS

“…9,34,49,70 Ring-like nanostructures have been demonstrated that they could be SERS materials. 9,34,49,70 Ring-like nanostructures have been demonstrated that they could be SERS materials.…”

Probing Localized Surface Plasmons of Trisoctahedral Gold Nanocrystals for Surface Enhanced Raman Scattering

“…The highest enhancement was observed for 1650 cm −1 mode. Considering the effective laser excitation volume of 514.5 nm laser (V = πr 2  = 15.32 μm 3 ;where r being radius of laser spot,  being depth of focus) by 100X objective (N.A = 0.85) and the surface area of a single TOH Au NP, the enhancement factor (EF) of a Raman mode was estimated11,13 by, EF = (I SERS N normal / I normal N SERS ).…”

Electrocatalysis enhancement of a screen‐printed carbon electrode by modification with trisoctahedral gold nanocrystals for H2O2 and NADH sensing application

“…The prepared TOH Au NCs are well‐shaped polyhedra comprising eight trigonal pyramids. The trisoctahedral, which is a shape rarely prepared for NCs, can be generated from an octahedron by pulling out the centers of the eight triangular faces . Generally speaking, all the 24 facets of a trisoctahedral belong to crystal planes of the family of the [110] zone axis, the Miller indices of which are hhl , and the limiting case is a dodecahedron.…”

“…The synthesis route of TOH Au NC is accomplished by the seed‐mediated growth method based on the report by Song et al . with a slight modification.…”