UPS SYNCHROTRON RADIATION STUDIES OF NH3 ADSORPTION ON TIO2(110)

The interaction of NH3 With perfect and defective TiO2(110) surfaces at 300 and 185 K has been studied using synchrotron radiation photoemission. To increase the sensitivity to Ti3+ states, the Ti p-d resonance at an incident photon energy of 47 eV has been used. Ammonia adsorbs mainly molecularly at low coverages at 300 K, with some amounts of NH2 and OH radicals. Upon annealling to high T both desorption and dissociation occurs, A maximum work function variation of -0.57 and -0.38 eV has been found for the perfect and defective surfaces, respectively. No significant differences in the electronic structure between adsorption at the two temperatures have been found, except for a higher coverage on the perfect surface.