Support and Particle Size Effects in Electrocatalysis - Fuel Cell Catalysis: A Surface Science Approach - page 565

Figure 16.1 Schematic of the UHV deposition system. TA, transfer arm; TC, Transfer

chamber.

between chambers by a transfer “railway” system and transfer arms. The “railway”
consisted of two trolleys on rails transporting the samples along the TC. Adjacent
to each chamber, a pickup mechanism and transfer arm allowed samples to be
brought into the chamber for deposition. The PVD deposition chambers were cryo-
pumped (Helix Tech. Corp.) and titanium sublimation-pumped (Varian), the TC
and CC were ion-pumped (Varian) and titanium sublimation-pumped. The load
lock was pumped by an oil-free rotary pump (Pfeiffer) and a turbo-molecular pump
(Pfeiffer).
Deposition of the materials was undertaken in growth chambers incorporating effu-
sion (Knudsen Source) and e-beam evaporation sources. Chamber I was equipped
with three off-axis Knudsen cells (K-Cell, DCA HTKS) and one centered electron
beam (e-gun, Temescal) evaporator. Chamber II consisted of six off-center sources,
three K-Cells, and three e-gun evaporators. Titanium (granules 99.95%, Goodfellow
Metals) was evaporated from either a high temperature K-Cell for operation up to
2000 8C using a pyrolitic graphite 10 cm 3 (Sintec Keramik) crucible or an e-beam
evaporator. Substoichiometric TiO x layers were deposited by oxidation of the titanium
during deposition by a collimated beam of molecular oxygen (BOC Special Gases, N6
grade) directed at the sample face. Carbon layers were deposited using an e-beam
evaporator source and graphite rods (Alfa Aesar, type 231-955-3). Carbon layers
were also deposited by means of an arc carbon coating system (BOC Edwards)
using carbon rods (BOC Edwards, type E085-19-030). Nanoparticles of Au and
Pt were grown by evaporation at low rates for short times. Au ( pellets 99.99%,
Goodfellow Metals) were evaporated from a low temperature K-Cell for operation
up to 1400 8C equipped with a 30 cm 3 Fabmate crucible (Kurt Lesker). Pt was evap-
orated from an e-beam evaporator.