Coaxial electrospinning (co-electrospinning) technique has greatly expanded the universality of fabricating core-shell polymer nanofibers. However, the effect of solution miscibility on the morphology of co-electrospun products remains unclear. Herein, different cellulose acetate (CA) solutions with high solution miscibility but distinctly different electrospinnability were used to survey the effect of solution miscibility on the co-electrospinning process. The structural characterizations show that co-electrospun products are composed of nanofibers with and without the core-shell structure. This indicates that partial solution mixing occurred during the co-electrospinning process instead of absolute no-mixing or complete mixing. Importantly, the solution miscibility also shows a significant influence on the product morphology. In particular, the transformation from nanofibers to microparticles was realized with the increase of core-to-shell flow ratio during the co-electrospinning of core electrosprayable CA/dimethylacetamide (DMAc) solution and shell electrospinnable CA/acetone-DMAc (2/1, v/v) solution. Results show that the solution miscibility exerts a significant effect on not only the formation of core-shell structure but also the product morphology. This work provides a new insight for the in-depth understanding of the co-electrospinning process.

Plasmon-induced photocatalysis on noble metal surfaces has attracted broad attention due to its application in sunlight energy conversion, while the selectivity of plasmonic platforms remains unclear. Herein, we present the controlled plasmon-mediated oxidation of para-aminothiophenol (p-ATP) by employing Au@Ag core–shell nanostars with tunable tip plasmons in visible–near-infrared range as reactors. In-situ Raman measurements indicate that Au@Ag core–shell nanostars essentially promote the conversion of p-ATP to 4,4′-dimercaptoazobenzene (DMAB) due to hot carriers excited by localized surface plasmon resonance. Au@Ag nanostars with plasmon modes under resonant light excitation suggested higher catalytic efficiency, as evidenced by the larger intensity ratios between 1440 cm⁻¹ (N=N stretching of DMAB) and 1080 cm⁻¹ shifts (C–S stretching of p-ATP). Importantly, the time-dependent surface-enhanced Raman scattering spectra showed that the conversion efficiency of p-ATP was mainly dictated by the resonance condition between the tip plasmon mode of Au@Ag core–shell nanostars and the excitation light, as well as the choice of excitation wavelength. These results show that plasmon bands of metal nanostructures play an important role in the efficiency of plasmon-driven photocatalysis.

Large-area three-dimensional (3D) well-ordered Co(OH)₂ nanoflower array films decorated with Ag nanoparticles (Ag NPs) with a novel structure were designed as sensitive SERS substrates for trace detection of pesticides.