Oxygen pairing on the highly non-stoichiometric (110) surface of

Experimental investigations have shown that bridging oxygen (Obr) atoms on the highly non-stoichiometric TiO2 (110) surface cluster together into nearest-neighbor pairs. Theoretically, this behavior has been observed in simulations of an Obr vacancy interaction model for TiO2 (110) in the high-vacancy-concentration limit. However, an interaction model that focuses on oxygen vacancies is ill-equipped to explain the behavior of interacting oxygen adatoms on a nearly fully reduced (i.e., Obr-depleted) surface. Therefore, to better understand this behavior, we have constructed an adatom–adatom lattice–gas model for oxygen on the fully reduced TiO2 (110) surface and performed an extensive set of Monte Carlo simulations on this model.