XPS and STM study of carbon deposits at the surface of platinum (110)

The deposition of carbon due to high temperature ethylene decomposition at Pt(110) was studied by XPS and STM techniques. In the temperature range 700–1400 K no graphite species were observed. Instead, two carbon states were distinguished by XPS. At temperatures 700–850 K chemisorbed carbon layer is formed with BE(C1s) = 284.2 eV, this carbon state reacting readily with both oxygen and hydrogen. At T > 850K carbon layer with BE(C1s) = 284.6–284.9 eV is formed. Further study showed this carbon species to be stable up to 1150 K and to be inert towards both hydrogen and oxygen up to 1000 K. This state was attributed to diamond-like carbon (DLC). STM study of DLC on Pt(110) revealed the patched pseudo-C-(3 × 1) structure. This reconstruction is believed to account for the DLC formation at platinum (110) surface.