Electrochemical Characterization of Magnetite (Fe(3)O(4)) Nanoaggregates in Acidic and Alkaline Solutions

[Image: see text] The electrochemical behavior of magnetite (Fe(3)O(4)) aggregates with submicrometric size is investigated. Specifically, cyclic voltammetry tests were performed in both acidic (pH ∼ 4.5) and alkaline (pH ∼ 12.8) solutions, exploiting a conventional three-electrode cell. In the first case, the working electrode was made of a glassy carbon substrate loaded with magnetite nanoaggregates, forming a continuous film. In a second configuration, magnetite nanoaggregates were dispersed in solution, kept under stirring, as a fluidized electrode. The latter approach showed an increase in the electrochemical response of the particles, otherwise limited by the reduced active area as in the former case. Electrochemical-atomic force microscopy (EC-AFM) investigation was carried out in an acidic environment, showing the topography evolution of nanoaggregates during the electrochemical characterization. X-ray diffraction (XRD) analysis was carried out to evaluate the microstructural variation in the Fe(3)O(4) electrodes after cathodic polarization tests in an alkaline environment.