A comparison between water adsorbed on Rh(111) and Pt(111), with and without predosed oxygen

摘要: The adsorption of water and its interactions with oxygen on Rh(111) were studied by high resolution electron energy loss spectroscopy (HREELS), temperature programmed desorption (TPD) ultraviolet X-ray photoelectron spectroscopies (UPS XPS), low diffraction (LEED); comparison was made similar data for Pt(111). On absorbs molecularly in hydrogen-bonded clusters; no evidence dissociation seen the clean surface. Reaction adsorbed produces hydrated surface hydroxyls. While gross features hydroxyl formation are to those previously reported Pt(111), significant differences detail found. In particular, complex librational OH-stretching regions HREELS spectra H 2 O/Rh(111), more closely resemble other noble metal surfaces than sharp, single feature observed peaks at 970, 1020 1950 cm −1 O/Pt(111) absent Rh(111). middle (3a 1 ) molecular orbital is shifted towards Fermi level, while Pt(111) spacing between three orbitals same as vapor. Comparison spectral bulk phases suggests that exists primarily a state O-O nearest neighbor distances closer liquid ice, allowing better match mesh. Additional minority species account additional EELS specific Water mixture ice-like majority structural lead different chemistry. both react yield phase which evolves upon heating 210 K. this contains OH but O. Rh (111) O association. these two catalytically electrochemically metals may help explain electrochemical effects peculiar face Pt.