Fig. 1.

(A) Schematic representation of the hybrid PDMS/quartz microelectrochemical device used for ORR studies. Solution is introduced to the microchannel using a syringe pump connected to the reservoir on the left. A combined reference/counter electrode is placed in the other reservoir so that it is in close proximity to PPC microband electrodes. Note that this drawing is not to scale. In the actual device, the length of the microband electrodes is typically 40 μm with a gap of 15 μm between them. (B) Optical micrograph of the PPC microbands and the microchannel after platinization of the collector electrode and electrochemical deposition of Pt DENs onto the generator electrode. The outlet reservoir is visible to the right of the electrodes.