Effects of the oxygen vacancy on NO adsorption at the TiO2 surface

The desorption spectrum of NO adsorbed on the surface of TiO2 (powder was determined by temperature programmed desorption. The molecular orbital theory was utilized to investigate the crystal cluster model of NO adsorbed on TiO)(2) (and the change of band gap in the adsorption process. The results indicate that there exist two peak temperatures, 450 and 980K, as N)(2) (desorption followed by the NO adsorption on TiO)(. The intensity of N)(2)(2) (desorption decreases if the TiO)(2) (powder is pretreated in an O)(2) (atmosphere. The nitrogen atoms of the adsorbed NO gas recombine into N2 for desorption while oxygen atoms occupy the oxygen vacancies in the TiO)(2) (surface. The calculation analysis from the molecular orbital theory supports the deduction that the existence of oxygen vacancy on TiO)(2)(110) surface offers a suitable condition of crystal surface for NO adsorption.