Understanding the interaction between oxygen molecules and metal oxide semiconductors surface is important for the development of gas sensors based on this kind of materials. The adsorption of oxygen molecules on these material's surface is (at) the basis of reactions between the surface oxygen species and the target gases molecules. The SnO2 (110) surface is the most stable and most dominant surfaces of the cassiterite SnO2 and they are experimentally very well characterised. In this work, we are investigating the adsorption of O2 molecules on the clean and defective SnO2 (110) surfaces by mean of Density Functional Theory (DFT). For the defective surface, three kinds of oxygen vacancies are considered: formations of bridging oxygen (Obridge) vacancy, in-plane oxygen (Oin-plane) and the formation of an oxygen vacancy in the subsurface (Osub-surf). We are investigating also the impact of the thickness of the material on the relaxation of the structure, we are using 3-5- and 7-layers structures. Our preliminary results showed that the formation of an in-plane and in the subsurface oxygen vacancy needs more energy than the bridging one and consequently only the bridging oxygen vacancies are considered in this work. The corresponding formation energies of the different kinds of oxygen vacancies are reported in table1. The adsorption of O2 molecule on the different SnO2 (110) surfaces was studied by calculating the adsorption energy Eads of the molecule, this later was relaxed in the same cell with the different considered surfaces and different modes are considered.
Adsorption of oxygen species on the SnO2 (110) surface: a Density Functional Theory investigation
Soufiane Krik;Andrea Gaiardo;Matteo Valt;Barbara Fabbri;Cesare Malagù;Vincenzo Guidi
2019
Abstract
Understanding the interaction between oxygen molecules and metal oxide semiconductors surface is important for the development of gas sensors based on this kind of materials. The adsorption of oxygen molecules on these material's surface is (at) the basis of reactions between the surface oxygen species and the target gases molecules. The SnO2 (110) surface is the most stable and most dominant surfaces of the cassiterite SnO2 and they are experimentally very well characterised. In this work, we are investigating the adsorption of O2 molecules on the clean and defective SnO2 (110) surfaces by mean of Density Functional Theory (DFT). For the defective surface, three kinds of oxygen vacancies are considered: formations of bridging oxygen (Obridge) vacancy, in-plane oxygen (Oin-plane) and the formation of an oxygen vacancy in the subsurface (Osub-surf). We are investigating also the impact of the thickness of the material on the relaxation of the structure, we are using 3-5- and 7-layers structures. Our preliminary results showed that the formation of an in-plane and in the subsurface oxygen vacancy needs more energy than the bridging one and consequently only the bridging oxygen vacancies are considered in this work. The corresponding formation energies of the different kinds of oxygen vacancies are reported in table1. The adsorption of O2 molecule on the different SnO2 (110) surfaces was studied by calculating the adsorption energy Eads of the molecule, this later was relaxed in the same cell with the different considered surfaces and different modes are considered.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
