A density functional theory study of the interaction of oxygen with a reduced SnO2 (110) surface

Ab initio thermodynamic study of the SnO2(110) surface in an O2 and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO2

“…This prediction was proved to be consistent with the experiment [28,29], and extended from bulk vacancy to surface oxygen vacancies at the SnO 2 surface [30][31][32][33][34][35][36].…”

“…The pre-adsorption of oxygen on the reduced SnO 2 surface is the first stage of the reducing gas sensing action, since sensors are in general exposed to air atmosphere before the introduction of gas [30][31][32]. Oxygen ionosorbs onto the surface, trapping conduction electrons from SnO 2 and creating a superoxo O − 2 or an atomic O − ion at the surface [37,38].…”

Photoemission study of the subsequential oxidation of dissociatively adsorbed methane on an SnO2 thin film

“…Very recently, we calculated the potential energy diagram for migration of dissociative oxygen on the cluster model of the reduced SnO 2 (110) surface using density functional theory (DFT). 22 The calculated barrier of migration was 12 kcal mol 1 , and this value was close to the removal energy of a hydrogen atom from methane with the O species at the bridging oxygen site. We therefore considered that if the O species had been presented, it would migrate to the sites of chemisorbed hydrocarbon species and react with them during further heat treatment.…”

Interplay between O2 and SnO2: Oxygen Ionosorption and Spectroscopic Evidence for Adsorbed Oxygen

“…[73][74][75][76][77][78][79][80][81] Despite strong disagreement in the description of the chemical state of adsorbed The oxygen molecule is thought to pick up the local electronic charge associated with reduced Sn 2 + ions, becoming either a peroxide [78,80] or superoxo ion. [76] This is considered as the formation of an electron-depleted space-charge layer which controls the electronic behavior of SnO 2 . [80] We have also to consider the strong disagreement between the EPR model of the "superoxide ion" (see above) [22,24] and theoretically predicted forms of adsorbed oxygen (at least for the SnO 2 A C H T U N G T R E N N U N G (110) surface).…”

“…[80] We have also to consider the strong disagreement between the EPR model of the "superoxide ion" (see above) [22,24] and theoretically predicted forms of adsorbed oxygen (at least for the SnO 2 A C H T U N G T R E N N U N G (110) surface). Almost all theoretical calculations (besides the work of Yamaguchi and Tabata et al) [73,76,78] predict side-on and end-on configurations of peroxide-like and superoxide-like species, respectively; where, in the interpretation of the EPR data, the paramagnetic superoxide ion is assumed to be oriented parallel to the surface (side-on). This indicates strong disagreement between theory and spectroscopic reality, which has also to be understood.…”