Correlation between Defect and Lattice States on Modulated TiO<sub>2</sub>(110) during Redox Reaction
Young Jae Kim, Daeho Kim, Yongman Kim, Yong-Chan Jeong, Han-Koo Lee, Jeong Young Park
Abstract
The correlations between the oxidation states and the ultrahigh vacuum-reconstructed TiO 2 (110) surface give insight into TiO 2 ’s defects, such as oxygen vacancy (V o ) and Ti interstitial, which induce excess electrons into the surface. Here, the nature of the atomic defects of TiO 2 (110) was investigated by combining scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) during redox reactions. We observed the reduced TiO 2 (110) by STM measurements, which was exposed to O 2 (g) and annealed to modulate the surface. The inverse changes were exhibited in the defect-related XPS peaks, Ti 3+ in Ti 2p and the defects in O 1s, compared to the lattice-related peaks, Ti 4+ in Ti 2p and O 2– in O 1s, because of V o healing and formation. XPS results show that the additional O 2 (g) dosing onto the oxygen-fully covered TiO 2 (110) induced the TiO x island formation, emphasizing the integrated analysis of the TiO 2 (110) surface reconstruction observation and the core-level spectral information.