Multifunctional core–shell Co–SiO₂ nanowires via electrodeposition and sol–gel techniques

Abstract

In this work, we propose a new strategy for the synthesis of multifunctional nanowires using a combination of sol-gel and electrodeposition techniques, based on a two-step procedure. First of all, nanotubes of SiO 2 are synthesized via a sol-gel technique using polycarbonate membranes as templates. Homogenous nanotubes are obtained after centrifugation and thermal annealing. Afterwards, a ferromagnetic cobalt core is grown using potentiostatic electrodeposition. Finally, the core-shell Co-SiO 2 nanowires are released by dissolving the template using wet-etching. These nanodevices can be used for many detection and sensing purposes. As a proof of concept, we have developed a pH nanosensor by including a pH-sensitive organic dye in the SiO 2 shell. The sensing principle is based on the optical response of the organic dye towards pH when added to a solution. The magnetic core allows the recovery of the nanosensors after use. These nanowires can therefore be used as recoverable pH nanosensors. By changing the dye molecule to another molecule or receptor, the procedure described in the paper can be used to synthesize nanodevices for many different applications.

A new way for lead–boron resin composite modification: SiO2 coated lead powders by a sol–gel method

“…In this work, the SiO 2 @Pb powders with different content of SiO 2 were synthesized by sol-gel. [20][21][22] The Pb powders and NH 4 OH were added into alcohol-water solution (volume ratio of alcohol to water was 5 : 1) with mechanical stirring. Then the TEOS was dropped by a constant ow pump with 0.5 mL min À1 under 25 C. Until the TEOS was dropped completely, the temperature was set to 80 C to get the SiO 2 @Pb slurry.…”

Electrodeposited Magnetic Nanowires with Radial Modulation of Composition

“…On the other hand, an electroless approach has also been used to coat ferromagnetic metallic NWs with a Au shell [ 24 , 25 ], with the focus on the development of biomedical applications. Finally, different chemical methods can also be used to grow a tube covering the nanoporous template and afterward filling the pore by electrochemical deposition [ 26 ]. Atomic layer deposition (ALD) allows high accuracy in the control of the coating thickness.…”

Scaling Up the Production of Electrodeposited Nanowires: A Roadmap towards Applications

“…These nanoparticles are normally synthesized by chemical methods [ 5 ] that are easily scaled-up, enabling real world applications [ 6 ]. Nanowires (NWs), which are much less widespread in applications than nanoparticles, have emerged in recent years, as nanomaterials have been called upon to play an important role in the development of breakthrough technologies in many fields, such as novel computation and data recording schemes [ 7 , 8 ], neuroscience [ 9 , 10 ], drug delivery [ 11 , 12 ], chemical sensing [ 13 , 14 ] or water splitting [ 15 , 16 ] among others. Electrodeposition is a very suitable growth technique for the fabrication of these nanomaterials.…”