Reactivity of the β-AlF3(100) surface: defects, fluorine mobility and catalysis of the CCl2F2 dismutation reaction

Hybrid exchange density functional theory is used to model defects on the β-AlF3 (100) surface. The stability of the surface with respect to the diffusion of surface F ions is investigated. It is shown that under typical reaction conditions (600 K) the surface is not kinetically hindered from reaching thermodynamic equilibrium. A reaction mechanism for the catalysis of 2CCl2F2 → CClF3 + CCl3F is proposed. The mechanism and corresponding reaction barriers are calculated using a double-ended transition state search method. It is predicted that the processes that determine the overall reaction rate occur at defect sites.