A study of the interaction of water vapour on clean and oxidized lead surfaces using photoelectron spectroscopy

Abstract

The interaction of H₂O vapour with clean and oxidized Pb(100) single crystal surfaces has been studied using photoelectron spectroscopy. The dean Pb(100) surface, does not react with H₂O vapour at 298 K but physisorbs H₂O at a very high sticking probability (~unity) at 80 K. The adlayer is completely desorbed at 150 K, leaving an atomically clean surface. At 80 K, H₂O is molecularly adsorbed on oxidized lead surface without decomposition, but on warming to 298 K there is a strong evidence for a significant decomposition. Exposure of the

Pb(100)-O surface to water vapour at 298 K leads to stoichiometric transfer in intensity from the oxide region to the hydroxyl region indicating the formation of PbO(OH)₂(s). Oxidized Pb(100) single crystal shows no catalytic tendency to decompose ethylene, propylene and acrolein in the temperature range (298-450 K).