Electron spectroscopy studies of the chemisorption of O2, H2 and H2O on the TiO2(100) surfaces with varied stoichiometry: Evidence for the photogeneration of Ti+3 and for its importance in chemisorption

摘要: Abstract Deposition of a monolayer titanium on the TiO2(100)-( 1 × 3) single crystal surface produces an oxygen deficient which has same chemical composition, electronic structure and reactivity as Ar ion sputtered TiO2(100) surface. From correlations with studies oxidation Ti(0001) surface, we provide firm evidence for existence Ti+3 species clean TiO2 The chemisorption O2, H2 H2O been studied by ultraviolet photoemission spectroscopy (UPS), electron energy loss (ELS), Auger (AES), low-energy diffraction (LEED) thermal desorption stoichiometric Ti+3-rich surfaces. presence causes distinct differences in nature bonding between adsorbed molecule substrate combination these studies, conclude that water is associatively TiO2(100)−( while it tends to dissociate into hydroxyl groups rich UPS ELS show adsorption changes different state, illumination band gap photons can regenerate reaction Ti+4 + e− → Ti+3. An attempt made correlate results well characterized surfaces using photoanode photo-electrochemical cell.