| A wide variety of porous metal nanostructures were fabricated by the galvanic replacement reaction using aluminum (Al) nanoparticle templates. The Al template particle, owing to its very low redox potential (-1.66 V vs. standard hydrogen electrode (SHE)), were replaced by such metals as nickel (Ni), cobalt (Co), copper (Cu), platinum (Pt), palladium (Pd), lead (Pb), silver (Ag), and gold (Au). Two distinct nanostructures have been fabricated from this template: discrete porous nanoparticles and continuous porous nanostructures. It was found that growth kinetics, driven by differences in reduction potentials, play an important role in the formation of these structures. SEM coupled with EDS, TEM with electron diffraction, and XRD are used to determine the elemental and structural composition of these porous nanostructures. Ni, Co, Cu, and Ag nanostructures were investigated as electrochemical sensors towards serotonin and hydrogen peroxide detection. Glassy carbon electrode, silver/silver chloride electrode, and a platinum wire were used as the working, reference, and counter electrodes, respectively. The GCE is modified with the porous metal nanoparticles and an ionic exchange membrane, Nafion. A cyclic voltammetry scan showed that nickel hollow nanoparticles enhance the oxidation of serotonin with a detection limit of 25 nM. The nanostructures showed inconsistencies towards the electrochemical detection of hydrogen peroxide and further analysis is needed to better understand the sensing behavior.;KEYWORDS: porous nanostructures, galvanic replacement, aluminum nanoparticle template, electrochemical biosensor, hydrogen peroxide, serotonin. |
