A computational study on the adsorption and ring cleavage of para-chlorophenol on anatase TiO 2 surface

Abstract

In this work, a computational technique based on semiempirical SCF MO method MSINDO, has been used for investigation of the adsorption and photocleavage of para-chlorophenol ( p-CP) molecule on the anatase TiO 2 (0 0 1) and (1 0 0) surfaces. The surfaces have been modeled with two saturated clusters Ti 21O 58H 32 and Ti 36O 90H 36. The optimization of the perpendicular conformation of p-CP molecule relative to the anatase TiO 2 (1 0 0) surface, has resulted in a linkage of the molecule to the surface titanium atom via phenolic oxygen atom. We studied the aromatic ring cleavage by singlet oxygen ( 1O 2) and superoxide radical anion ( O 2 • - ) and accordingly, relevant mechanisms are suggested. The results reveal that the ring opening path of p-CP molecule on TiO 2 (1 0 0) surface, following the single electron transfer/ O 2 • - mechanism, is energetically more favourable than the 1O 2/dioxetane mechanism.