Abstract
Bimetallic nanomaterials, which exhibit a combination of the properties associated with two different metals, have enabled innovative applications in nanoscience and nanotechnology. Here, we introduce the fabrication of dendritic Au/Ag bimetallic nanostructures for surface-enhanced Raman scattering (SERS) and catalytic applications. The dendritic Au/Ag bimetallic nanostructures were prepared by combining the electrochemical deposition and replacement reaction. The formation of Au nanoparticle shell on the surface of Ag dendrites greatly improves the stability of dendritic nanostructures, followed by a significant SERS enhancement. In addition, these dendritic Au/Ag bimetallic nanostructures are extremely efficient in degrading 4-nitrophenol (4-NP) compared with the initial dendritic Ag nanostructures. These experimental results indicate the great potential of the dendritic Au/Ag bimetallic nanostructures for the development of excellent SERS substrate and highly efficient catalysts.
Highlights
Synergy of two or more metal materials enables the fabrication of all-in-one nanostructures with multi-functionalities [1, 2]
After longer replacement reaction time (150 s), the dendritic structure was broken to form leaf-like rods and particles and a large number of pores and cavities appeared due to the removal of Ag from the initial Ag dendrite (Fig. 1d)
A tunable localized surface plasmon resonance (LSPR), surface-enhanced Raman scattering (SERS) and catalytic activity were obtained by tuning replacement reaction time
Summary
Synergy of two or more metal materials enables the fabrication of all-in-one nanostructures with multi-functionalities [1, 2]. Bimetallic nanostructures comprised of noble metals (such as Au, Ag, Pt, and Pd) exhibit special optical, electronic, and catalytic properties owing to the synergistic effect of monometallic nanostructures [1–7], and have potential applications in the fields of catalysis [5–12], surface-enhanced Raman scattering (SERS) [13–18], and sensors [19]. Nanostructured Ag are better candidates for SERS because of their low damping rate compared with Au [13, 14], yet Ag suffers from low chemical stability (e.g., surface oxidation) which limits the development of Ag-based SERS substrates with long operating lifetimes. Metal nanostructure-based catalyst with high activity and selectivity are highly desirable for chemical reactions in industry. Diverse types of Au/Ag bimetallic nanostructures, such as Au-Ag hollow nanoparticles, nanowires, and nanodendrites, have been reported to exhibit superior catalytic activities to both Au and Ag monometallic counterparts [9–11]. Bimetallic nanostructures offer a promising strategy for controlled catalyzing, which could be in-suit monitored by the SERS signals in real-time [20, 21]
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