Date Published: June 05, 2012
Publisher: WILEY-VCH Verlag
Author(s): Arne Kloke, Christian Köhler, Ramona Gerwig, Roland Zengerle, Sven Kerzenmacher.
Electrode fabrication: Substrates are fabricated by evaporation of 50 nm of titanium and 250 nm of platinum onto a 4’’ silicon wafer (<100> orientation, 525 μm thickness, n+ type doped). Before use samples were cleaned in acetone, isopropyl alcohol and water in an ultrasonic bath and weighted (SC 2, Sartorius, Göttingen, Germany). A screwed assembly of polycarbonate and silicone rubber pieces was used to connect two platinum wires (50 μm diameter, Chempur, Karlsruhe, Germany) to the electrode, exposing a geometric area of 1 cm2 as shown in 40. Electrodes used in fuel cell assemblies were fabricated with a geometric area of 2.25 cm2. Ten CV scans (50 mV s−1, 1.40 to −0.40 V vs. SCE) in 0.5 m H2SO4 (Merck, Darmstadt, Germany) were performed under N2 atmosphere to electrochemically clean the substrate’s surface. During fabrication and characterization a potentiostat (PCI4/300, Gamry Instruments, Warminster PA, USA) was used with a platinum counter electrode and a saturated calomel reference electrode (SCE, KE11, Sensortechnik Meinsberg, Ziegra-Knobelsdorf, Germany).