The Nature of the Surface Species Formed on Au/TiO2 during the Reaction of H2 and O2: An Inelastic Neutron Scattering Study

Inelastic neutron spectroscopy (INS) has been employed to identify surface species formed during the H2-O2 reaction on Au/TiO2 catalysts. Determination of the surface intermediates formed in this reaction is crucial to develop a mechanistic understanding for the direct vapor-phase propylene epoxidation reaction and synthesis of H2O2. Although the presence of intermediate hydroperoxo species (during these reactions) has been suggested in literature, it has never been demonstrated. Our studies provide direct evidence for the formation of surface hydroperoxo species during the H2-O2 reaction.