Density Functional Study of the Properties of CO Adsorption on SnO2(110) Surface

Based oil density functional theory in the generalized gradient approximation, together with the total energy plane-wave Pseudopotential, adopted a six-layers periodic slab model, four modes of CO adsorption Oil SnO2(110) surface were calculated and the surface property modifications due to CO adsorption were investigated. The results indicate that the most stable adsorption mode is associated to the CO with the C-end oriented to the five-coordinated Sn ion, and this adsorption mode improves the relaxation of the surface. The distribution of the electronic states of surface has no remarkable change after CO adsorption, but the Fermi level has 1.06 eV shift to a high-energy direction. Adsorption resulted in a 0.07 electron transfer from CO molecule to the surface, which causes the decrease of the surface resistance. The present results favor the surface conductance model of the sensitive mechanism of gas sensors.