In Situ SERS Monitoring of the Plasmon-Driven Catalytic Reaction by Using Single Ag@Au Nanowires as Substrates

Abstract

Single nanowires (NWs), as a kind of new surface-enhanced Raman scattering (SERS) substrates, have received extensive concern owing to their distinctive properties and distinct advantages. In this contribution, single Ag nanowires (AgNWs) and single Au-coated AgNWs (Ag@AuNWs) were fabricated by the laser-assisted pulling method and the galvanic replacement reaction, respectively. The prepared single Ag@AuNWs show both high SERS activity and catalytic activity through in situ monitoring and assessing the plasmon-driven surface-catalytic reaction of 4-nitrothiophenol (4-NTP) dimerizing to 4,4′-dimercaptoazobenzene and the reduction reaction of 4-NTP to paraaminothiophenol, respectively. It was found that the intensity of the Raman peak was affected greatly by the laser power, and the Raman peak could still be observed at 0.05% power under mild conditions (633 nm wavelength) in this single nanowire system. From the Raman spectrum, the SERS enhancement factor (EF) of 5.4 × 10 4 can be obtained, and the EF value of 1.3 × 10 9 can be reached at optimal conditions. Results have shown that single Ag@AuNWs can be utilized as a good platform for SERS applications with high sensitivity, stability, and reproducibility, which will benefit SERS-based research at the single entity level.

Single-Molecule Investigation of the Protein–Aptamer Interactions and Sensing Application Inside the Single Glass Nanopore

“…According to eq , the orifice diameter is 34.2 nm. The DNA aptamer sequence of carcinoembryonic antigen (CEA) was fixed on the nanopore inner wall through Au–S chemical modification, , The successful modification of this process could be demonstrated by the I – V response (Figure S5). During the modification process, the negatively charged phosphate backbone of DNA would increase the surface charge density on the inner wall of the nanopore.…”

Construction of Ag nanowire@Au nanoparticle nano nests with densely stacked small gaps for actively trapping molecules to realize diversity SERS detection

“…Li group used gold covered Ag NWs (Ag@Au NWs) through the noble replacement reaction (GRR) with high SERS activity and catalytic activity. 21 Our group also previously reported a SERS-active platform using spontaneous capillary imbibition to assemble a single Au NP onto the surface of a single Ag NW. 22 Therefore, the coupled nanostructures not only generate a high electromagnetic field, but also promise to provide the SERS hot spot platform.…”

Synergistic SERS enhancement and in situ monitoring of photocatalytic reactions in a plasmonic metal/ferroelectric hybrid system by the light-induced pyroelectric effect

“…It is well known that the photocatalytic reaction of p-NTP to form DMAB is initiated by hot electrons, induced by surface plasmon resonance (SPR) of Ag nanowires. 54,55 In addition, the SERS intensities of the MB molecules at different irradiation times were collected and the linear equation was plotted as shown in Fig. S2.…”