This paper describes a straightforward approach for the decoration of Ag nanoparticles onto the surface of mesoporous silica nanorods (denoted as SiO 2 @Ag nanocomposite rods), in which polyvinylpyrrolidone (PVP) is served as both reductant and stabilizer. In this approach, mesoporous silica nanorods are initially synthesized through a binary surfactant template method by using CTAB and F127 in a basic aqueous solution. Subsequently, through the electrostatic attraction between the negatively charged silanol groups and the positively charged [Ag(NH 3 ) 2 ] + ions, the silver precursor-[Ag(NH 3 ) 2 ] + ions can be adsorbed onto the surfaces of mesoporous silica nanorods. Then, those [Ag(NH 3 ) 2 ] + are in-situ reduced to metallic Ag nanoparticles and stay there with the protection of PVP, consequently, SiO 2 @Ag nanocomposite rods are formed. By adjusting the concentration of [Ag(NH 3 ) 2 ] + ions, the size of Ag nanoparticles and the surface coverage of mesoporous silica nanorods by Ag nanoparticles can be easily tailored. During the synthesis, neither the additional reductants nor the surface modifications are necessary. These as-synthesized SiO 2 @Ag nanocomposite rods show excellent catalytic activity for the reduction of organic dyes, which may be useful for the wastewater treatment. Furthermore, these SiO 2 @Ag nanocomposite rods are ideal candidates as the surface-enhanced Raman spectroscopy (SERS) active substrates for the trace detection of antibiotics, i.e., Penicillin G sodium and Chloramphenicol. This SERS feature may be applicable for the organic residue detection in food.
Surface‐enhanced Raman scattering (SERS) is considered a promising analytical technique for the detection of analytes. Considering the practical SERS detection, it is necessary to develop low‐cost, highly sensitive, and recyclable SERS‐active substrates. Here, a simple and flexible approach is proposed to fabricate a superhydrophobic Ag‐decorated CuO (named as CuO@Ag) nanowire array substrate with analyte‐concentrating and self‐cleaning binary functions for ultrasensitive and recyclable SERS detection. During this process, a superhydrophobic CuO@Ag nanowire array is made via fabrication of a CuO nanowire array by oxidizing and calcinating an ordered porous anodic aluminum oxide template on Cu foil, and following with Ag sputtering deposition on CuO nanowire array. Remarkably, this SERS substrate exhibits ultrasensitive SERS detection ability attributed to superhydrophobic plasmonic metal nanostructured arrays with high analyte‐concentrating ability and excellent photocatalytic capability due to this metal‐semiconductor composite nanostructure. These advantageous properties allow for SERS detection of malachite green with a limit of detection of 6.73 × 10−13 m and self‐cleaning via photodegradation of adsorbed analytes with visible‐light illumination. Consequently, it achieves recyclable SERS detection. This research demonstrates a simple and flexible approach for fabricating recyclable SERS‐active substrate, which expands the practical SERS applications in chemical and biological analysis, food safety, and healthcare.
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