Nickel nanobrush platform for a magnetic field-assisted electrochemical response enhancement

Abstract

A single-step electrochemical procedure to synthesize a brush-like platform (composed of a nickel nanowire array attached to a nickel continuous layer acting as a solid base, is described. Room temperature hysteresis properties of this brush-like architecture (nanobrush) and those of the individual components (nanowires and layer) are determined. It is shown that the direction of the nanobrush magnetic easy axis may be tailored, being also possible to control the magnetic system's coercivity and remanence. The electrochemical response and the catalytic activity of a Ni nanobrush towards the redox probes [Fe(CN)6]4-/3- and ethanol were evaluated in the presence and absence of an applied magnetic field. The external field strongly affects the system's behavior by enhancing the electrode charge-transfer response, even at fields as low as 6 mT. This improvement was further investigated by Electrochemical Impedance Spectroscopy and Electrochemical Capacitance Spectroscopy studies. It is concluded that the enhanced electrochemical charge-transfer process of the Ni nanobrush electrode, with a magnetic field applied along the Ni nanowires axis, arises from a larger electroactive area.