Comparative Study of the Adsorption Mechanism and Photochemical Oxidation of Chlorophenols on a TiO₂ Nanocatalyst

摘要

The anatase structure of titanium dioxide (TiO2) nanoparticles was prepared via solel technique andinvestigated by X-ray diffraction (XRD). The activity of TiO2 was evaluated by photocatalyticdegradation of chlorophenolic compounds namely 2-chlorophenol (CP), 2,4-dichlorophenol (DCP) and2,4,6-trichlorophenol (TCP) under solar radiation. A computational technique based on semiempiricaland density functional theory (DFT) was used to study the effects of chlorophenolic compoundsadsorption on the anatase TiO2 (100) surface. Then, EHOMO, ELUMO and 咵 were evaluated by threemethods, each of which uses density functional theory (DFT) with semiempirical methods. Amolecular dynamics (MD) simulation was employed to obtained a great understanding of theadsorption behavior of chlorophenolic compounds on the anatase TiO2 (100) surface. The results of theCP and DCP molecules revealed a perpendicular adsorption via chloride with the surface latticetitanium ion, while this behavior was changed to planar for TCP. To make a comparison betweenexperimental and theoretical calculations, the adsorption energies of chlorophenolic molecules werefound to be increased in the order TCP < DCP < CP, as confirmed with the photocatalytic degradationefficiency from the experimental data.