Prof. Liangbao Yang, etc. from Prof. Jinhuai Liu’s group synthesized a single and optical visualization Surface-Enhanced Raman Scattering (SERS) nanoreactor, which has been used for in situ monitoring plasmon-driven and small Au nanoparticles catalyzed reactions. The corresponding results have been accepted by Chemical Communication (2015, DOI: 10.1039/C5CC03792A).
Recently, plasmon-driven chemical reactions have attracted much attention since they opened up a new approach for monitoring and studying reactions on metal catalysts. Also, it is well known that SERS is the powerful analytical technique that can provide non-destructive and ultrasensitive characterization down to the single molecular level. Besides, it can provide the fingerprint information of analytes compared with other spectroscopy methods.
However, a fundamental challenge of facile constructing regular and reproducible hot-spots still exists in the most of SERS active-substrate, which results in irreproducible SERS signals. Aiming at this problem, researches synthesized the hybrid Au-Ag nanostructures with well-defined and reproducible structures. Here, the single nanowire-SERS activity was compromised because of the absorption shift associated with longitudinal resonances into the infrared region. Nonetheless, modifying the NPs on the NW to form ordered one-dimensional nanoreactor should be proposed since coupling of plasmon in adjacent NPs and NW was beneficial to offer highly sensitive and reproducible SERS signals. Thus, the single nanowire was used as template, and the positive Au nanoparticles are uniformly modified on the surface of Ag nanowire with electrostatic adsorption.
This ordered one dimensional nanoreactor is beneficial to offer highly sensitive and reproducible SERS signals due to the coupling of plasmon in adjacent NPs and NW. Besides, decorating the Ag NW with catalytically small size Au NPs to fabricate coupled plasmon nanostrcture can not only monitor plasmon-driven reactions, but study Au NPs-catalyzed reactions by SERS as well. Moreover, single Ag NW with 10 m length can be conveniently located by optical micros copy, which limits the catalytic reactions in the fixed position and avoids the sounding noise.
In short, this single Ag NW-Au NPs nanoreactor provides coupled plasmon as well as oriented NPs arrays, in which it can be used as active platform for in situ SERS monitoring catalyzed reactions with high sensitivity and reproducibility. Furthermore, this single nanoreactor has the potential of expanding a market for SERS sensing in field of hybrid metal-metal nanostructure catalysis.
This work was supported by the National Natural Science Foundation of China(21305142), National Basic Research Program of China (2011CB933700), the National Instrumentation Program of China (2011YQ0301241001 & 2011YQ0301241101).
Schematic illustration of plasmon-driven and small Au nanoparticle-catalyzed reactions