Nanostructured copper coated carbon microelectrodes for SERS sensing prepared by electrochemical/electrophoretic technique
| Authors | |
|---|---|
| Year of publication | 2016 |
| Type | Article in Proceedings |
| Conference | 67th Annual Meeting of the International Society of Electrochemistry |
| MU Faculty or unit | |
| Citation | |
| Field | Physical chemistry and theoretical chemistry |
| Keywords | nanostructured copper coated carbon microelectrodes; SERS; electrodeposition; carbon fiber microelectrodes |
| Description | We report on a novel method for fabricating nanostructured copper-coated carbon cylindrical fiber microelectrodes and show the high efficiency of these electrodes in SERS. Carbon fiber microelectrodes (CFMEs) can be utilized as highly sensitive miniaturized SERS substrates after coating with metal nanostructured layer. Thereby, we developed a facile technique enabling CFMEs to be modified with nanostructured copper layers. The procedure for CFME modification by copper is based on electrochemical/electrophoretic procedure, i.e. electrodeposition of the material formed by the dissolution of the anode. Copper wire was anodized in a two-electrode cell containing ultrapure water as the medium while the CFME was connected as the cathode, the interelectrode distance being 1 cm. Due to the low conductivity of ultrapure water, relatively high potentials (10–30 V) had to be employed to induce copper anodic dissolution. The formed anode-derived copper hydroxide is transferred towards the cathode by movement through the interelectrode space originating from the combined action of migration, diffusion and convection induced by thermal and density gradients. Reductive deposition occurs at the cathode, yielding nanostructured copper deposit in the form of mesh-like, random oriented copper nanowire network. The dimensions of nanowires, estimated from SEM image are 8-10 nm in diameter and several hundreds of nanometers in length. After coating the CFME with copper, the carbon-like Raman spectrum is significantly attenuated. Surface enhanced Raman spectra of rhodamine 6G standard were acquired at metal – solid interface by placing a drop (5µL) of its aqueous-ethanolic solution (50% v/v) onto Cu-coated CFME SERS substrate and evaporating the solvent. The performance of the substrate was also evaluated by testing its ability to obtain SERS from extremely diluted aqueous-alcoholic solutions of cathinone drugs. It was found that evaporating 5µL of 10-10 M solution of the substrate provides Raman spectrum with similar signal to noise ratio as the spectrum of 4-mephedrone powder, furthermore, main spectral features are detectable from10-12 M solutions. |
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