Switching “on and off” faradaic electrochemistry at an otherwise passivated electrode using gold-coated magnetic nanoparticles

•Gold electrodes modified with 11-mercaptoundecanoic acid•Absorption of gold-coated magnetic nanoparticles to modified gold electrode•Electrochemical switching using nanoparticle mediated electrochemical gating

Herein we combined the use of self-assembled monolayer (SAM) modified electrodes and gold coated magnetic nanoparticles (Au@MNPs) to modulate faradaic electrochemistry when nanoparticles are absorbed on and removed from, a passivated electrode using an external magnetic field. Substantial faradaic electrochemistry of potassium ferricyanide in solution is first prevented by modifying gold electrodes with 11-mercaptoundecanoic acid to form a passivating SAM. Restoration of the faradaic electrochemistry is then achieved by introducing Au@MNPs which are brought to the surface using an external magnetic field. The faradaic electrochemistry can again be suppressed by removing Au@MNPs from the SAM using another external magnetic field.

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