Adsorption of oxygen atom on the pristine and antisite defected SiC nanotubes

The structural and electronic properties of a single oxygen atom adsorbed on the exterior surface of pristine and antisite defected (6,6) and (10,0) SiCNTs have been investigated systematically using the first-principles projector-augmented wave potential within the density-functional theory under the generalized gradient approximation. We find that the oxygen atom can adsorb exothermically or spontaneously on the exterior surface of pristine (6,6) and (10,0) SiCNTs and the most favorable adsorbing sites are the bridge site B1 above the Si-C bond perpendicular to the tube axis and the bridge site B2 above the zigzag Si-C bond, respectively. Similar stable configurations are also obtained for CSi or SiC defected (6,6) and (10,0) SiCNTs, but the C-C or Si-Si bond below oxygen adatom is broken. Except for B1 site of CSi antisite defected (6,6) SiCNT, shortly CSi(6,6)B1, the SiC(6,6)B1, CSi(10,0)B2 and SiC(10,0)B2 assist the oxygen adsorption in point of view of the binding energy.