Adsorption and photoexcitation of NO on Ag/Pt(1 1 1)

The adsorption and photoreaction of NO on Ag films deposited on Pt(1 1 1) were investigated at 90 K by reflection-absorption infrared spectroscopy (RAIRS). Similar to Ag(1 1 1), NO molecules were found to be converted into (NO)2 and N2O on the Ag films. At an Ag thickness of 1 ML, however, a new adsorption state that reveals a RAIRS band at 1848 cm−1 is present on the surface. The (NO)2 dimer species was found to react into N2O, while the reaction of the new species was substantially suppressed. Upon photon irradiation with a wavelength of 193 nm, the three adsorption species on Ag(1 ML)/Pt(1 1 1) were depleted from the surface. The origin of the newly found species and the photoreaction mechanism are discussed.