The ability to measure localelectrochemical current density is important to a number of applications includingthe high throughput evaluation of electro-catalysts and corrosion studies. We presenta technique called imaging amperometry that measures local current density via theresponse of probe particles near a working electrode. Single particlelongitudinal (ie. vertical) and multi-particle lateral motion is a function ofthe intensity and direction of local current density. This presentation willfocus on single particle vertical motion. Measurements are conducted using an ElectrochemicalTotal Internal Reflection Microscope (ETIRM) that combines techniquestraditionally found in colloid science (TIRM) and electrochemistry (cyclicvoltammetery). We demonstrate this technique using a continuous indiumtin-oxide (ITO) thin film electrode, a discontinuous ITO thin film electrode,and a continuous (but electrochemically patchwork) ITO/gold thin film electrode.In all cases, we are able to measure local electrochemical activity bymonitoring the scattered light intensity from the particle.

Imaging amperometry

241st National Meeting (2011)

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