Study on the Adsorption of SF6 Molecules on the Surface of TiO2(001)Based on DFT+U Theory
SF6 gas exhibits a potent greenhouse effect.Research on SF6 degradation and conversion is of great signifi-cance for environmental protection.Based on the DFT+U theory,the adsorption and decomposition processes of SF6 molecules on the defective surface of TiO2(001)were investigated.The results show that there is a strong interaction be-tween the SF6 molecules and the TiO2 surface,with adsorption energy reaching-5.280 eV,which is presumed to be a possible chemisorption process.According to the Mulliken charge analysis,electrons are transferred from the TiO2 sur-face to the SF6 molecules,in which SF6 behaves as an electron acceptor and TiO2 as an electron donor.According to the result analysis of the density of states,there is a clear overlap of electron orbitals between the S and F atoms of the SF6 molecule and the Ti and O atoms on the TiO2 surface.In addition,the differential charge density results also confirm this charge transfer process.The molecular structure of SF6 will change significantly before and after adsorption,and the elongation of the S—F bond will facilitate the SF6 molecule more susceptible to decomposition.The study shows that TiO2 has the potential to catalyse the degradation of SF6 insulating gas and provides theoretical supports for the experi-mental study of efficient and harmless treatment of SF6.
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