Density functional study of chloroethene reactions with iron surfaces

The reactions involved in reduction of trichloroethylene (TCE) and tetrachloroethylene (PCE) at metallic iron surfaces were studied. The Perdew-Burke-Enzerhof functional was used to model both physical and chemical adsorption of TCE and PCE at different sites on the iron surface. Initial configurations with the C=C bond physically adsorbed at bridge sites between adjacent iron atoms resulted in di-sigma bond formation between two C and two Fe atoms and activation of all three C-Cl bonds. Initial configurations with the C=C bond physically adsorbed at a top site above a single Fe atom, or at a hollow site between four Fe atoms, resulted in only one C atom binding to the iron and activation of only two C-Cl bonds. Chemisorbed structures formed at bridge sites were the most energetically favorable and had early transition states with activation energies of ∼ 50 kJ/mole. This is an abstract of a paper presented at the 231th ACS National Meeting (Atlanta, GA 3/26-30/2006).