The reported mechanical strength of carbon nanocoils (CNCs) obtained from traditional preparation of catalytic acetylene pyrolysis is far below its theoretical value. Herein, we report a molten salt electrolysis method that employs CO3 2– as feedstock to grow CNCs without using metal catalyst. We meticulously mediate the alkalinity of molten carbonate to tune the electrochemical reduction of CO3 2– on graphite electrode to selectively grow CNCs in Li2CO3–Na2CO3–K2CO3–0.001 wt %Li2O. Graphite substrate, current density, and alkalinity of molten salt dictate the growth of CNCs. In addition, the electrolytic CNCs shows a spring constant of 1.92–39.41 N/m and a shear modulus of 21–547 GPa, which are 10–200 times that of CNCs obtained from catalyst-assisted gas-to-solid conversions. Overall, this paper opens up an electrochemical way to prepare CNCs through liquid-to-solid conversion without using catalysts and acetylene, providing new perspectives on green synthesis of 1D carbon nanomaterials with high mechanical strength.

Surface-enhanced Raman scattering (SERS), due to its extreme sensitivity down to the single molecule level, has been a superior analytical technique for (bio)chemical sensing and monitoring. However, the reliability of SERS has been a major issue since its discovery and has not yet been fully addressed, which is largely due to the lack of properly designed SERS substrates and facile, cost-effective fabrication strategies of metallic nanostructures. Herein, we employ hierarchical metallic nanopatterns as active SERS substrates, which can be facilely fabricated by superplastic nanomolding of bulk metals with hierarchical anodic aluminum oxide templates. The SERS signals of such hierarchical metal substrates show both high sensitivity (SERS intensity of up to 10 6 with an enhancement factor of ∼7.0 × 10 5 ) and reproducibility (relative standard deviation as low as 7%) with an optimized configuration, which significantly outperforms that without hierarchical nanostructures. Our results reveal that the microcavities of the hierarchical molds can significantly reduce the nonuniform plastic deformation of the bulk metals caused by surface roughness, while the nanoholes in the microcavities yield densely packed nanopillars with exceptional SERS signals. These hierarchical metallic nanostructures are further applied for the detection of biomolecules and organic dyes with concentrations as low as 10 −10 M, whose SERS intensity still presents a prominent signal-to-noise ratio. Such facile and scalable fabrication of hierarchical metallic nanostructures not only sheds light on the key factors that affect the uniformity and sensitivity of SERS but also provides guidelines for rational design of superior SERS substrates with outstanding performances, which is of great implication for (bio)chemical sensing and pollutant monitoring.

Active plasmonic systems have attracted numerous research interests as they have played a central role in functional devices and many emerging applications. However, current tuning strategies are either static/irreversible or...

Ordered metallic nanostructures, due to their superior electronic and photonic properties, have played a vital role in wide range of applications, such as metamaterials, plasmonic sensing, electrocatalysis, and energy devices. However, traditional fabrication strategies based on bottom‐up self‐assembly and top‐down lithography are either poor in uniformity or time‐consuming with low scalability. Here, a robust and cost‐effective approach for the fabrication of highly ordered metallic pillars arrays in centimeter scale is presented. This is realized by superplastic nanomolding of metals with highly ordered anodic aluminum oxide templates which are fabricated by the prepatterning of aluminum sheets with bulk metallic glass (BMG) mold, followed by anodizing. The nanopatterning process is rationalized with finite element simulation to avoid the damage of BMG mold. Finally, it is shown that the molded metallic sub‐micrometer pillars arrays can be used for the surface‐enhanced Raman scattering (SERS) with enhancement factor of ≈106. It is found that the SERS performance is influenced by the specific surface area of the pillars in addition to the near‐field intensity. This simple and cost‐effective method not only opens new opportunities for rapid prototyping of large‐scale ordered metallic nanostructures for various applications but also provides guidance for the quantitative analysis on sub‐micrometer scale.

Photons as energy carriers are clean and abundant, which can be conveniently applied for nanoactuation but the response is usually slow with very low energy efficiency/density. Here, we underpin the concept of robust nanoscale plasmonic dynamite by incorporating fullerene (C60). The Au@C60 core–shell nanoparticles can be triggered to explode in nanoscale with synergy of plasmon-enhanced photochemical and photothermal effects. It is suggested that a sensible amount of CO2 was generated and pressurized in nanometric volume in an extremely short time scale (∼ns), which triggers the nanoexplosion, rendering the ejection of Au NPs at the speed over 300 m/s. The ejection generates extremely large local forces (∼1 μN) with thermomechanical energy efficiency up to ∼30%, which is demonstrated as a powerful nanoengine for controlled mobilization of micro-objects on solid surfaces. Such nanoscale plasmonic dynamite is highly exploitable for different types of nanomachines, which provides a powerful energy source for nanoactuation and nanomigration.