Molecular and dissociative adsorption of a diethylsulfide molecule on (010) and (001) faces of a TiO₂ anatase nanoparticle

Adsorption of aliphatic sulfide on the faces of a 1.4×1.4×2.1 nm anatase nanoparticle of the stoichiometry Ti₁₁₄O₂₂₈ with ideal (001) and (100) faces are considered in this work. Molecular adsorption on the (001) face proceeds with the enthalpy varying from -6 kcal/mol to -38 kcal/mol by coordinating the sulfide sulfur atom to titanium and oxygen atoms, with the most exothermic adsorption occurring on atoms of the edges between (001) and (010) or (100) faces. Molecular adsorption on the (100) face proceeds with the enthalpy varying from -18 kcal/mol to -30 kcal/mol by coordinating the sulfur atom to oxygen atoms or simultaneously to oxygen and titanium atoms. In molecular adsorption complexes the S-Ti coordination bond length is 2.56-2.69 Å and the S-O bond length is 2.35-2.57 Å. Dissociative adsorption is observed on the (100) face and proceeds with the enthalpy up to -23 kcal/mol by coordinating the thiyl group to titanium and oxygen atoms and the ethyl group to surface oxygen atoms.