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 TiO2 and the change of band gap in the adsorption process. The results indicated that there existed two peak temperatures, 450 and 980K, as N2 desorption followed by the NO adsorption on TiO2. The intensity of N2 desorption decreased if the TiO2 powder was pre-treated in an O2 atmosphere. The nitrogen atoms of the adsorbed NO gas recombined into N2 for desorption while oxygen atoms occupied the oxygen vacancies in the TiO2 surface. The calculation analysis from the molecular orbital theory supported the deduction that the existence of oxygen vacancy on TiO2(110) surface offered a suitable condition of crystal surface for NO adsorption.

Effects of the Oxygen Vacancy on NO Adsorption at the TiO2 Surface. Wang, Y., Meng, L.: Acta Physica Sinica, 2005, 54[5], 2207-11