Modifying ultramicroelectrodes with multi-layer graphene fragments for use in scanning electrochemcial microscopy

Scanning Electrochemical Microscopy (SECM) is an electroanalytical tool capable of acquiring quantitative, localized measurements and imaging of electrochemical systems including reactions at electrode interfaces, energy storage materials, and catalysis. SECM is a scanning probe microscopy technique that utilizes a small conductive probe on the micro to nanometer scale submerged in an electrolyte solution. SECM experiments often involve reactions at the probe with redox-active species either added in or produced from the substrate for data acquisition. Few approaches have been explored for ion-sensitive probes that can quantitatively measure ion movement at electrode interfaces in spite of the ubiquitous role ions play in electrochemical processes. Our group has applied mercury amalgam-based probes for studying a variety of energy storage systems. However, the probes often suffer from oversaturation in high ionic concentrations, and this issue becomes compounded as the probe-size is decreased. Here, we investigate modifying micro and nanoelectrodes with multi-layer graphene for use in local micro to nanoscale mapping of reactivity at small graphene fragments and ionic fluxes at nanoparticle interfaces.Ope