Influence of LiTaO 3 (0001) and KTaO 3 (001) Perovskites Structures on the Molecular Adsorption of Styrene and Styrene oxide: A Theoretical Insight by Periodic DFT Calculations.

In this research, the adsorption of styrene and styrene oxide, both biomass derivatives, on KTaO (001) and LiTaO (0001) perovskite-like structures was studied from a theoretical point of view. The study was carried out using density functional theory (DFT) calculations. The adsorption phenomenon was deeply studied by calculating the adsorption energies (E ), adsorbate-surface distances (Å) and evaluating the differences of charge density and charge transfer (ΔCT). For complexes adsorbed on KTaO (TaO , KO and K(OH) exposed layers), the highest E was found for styrene oxide, attributed to the oxygen reactivity of the epoxy group describing a strong interaction with the surface. However, when evaluating a K(O) model, a more favorable interaction of styrene with the surface is observed, resulting in a high E of -9.9 eV and a ΔCT of 3.1e. For LiTaO , more favorable interactions are found for both adsorbates compared to KTaO , evidenced by the higher adsorption energies and charge density differences, particularly for the styrene complex adsorbed on TaO exposed layer (E : -10.2 eV). For the LiO termination, the surface exposed oxygens are fundamental for the adsorption of styrene and styrene oxide, leading to a considerable structural distortion. The obtained results thus provide understanding of the structural features, surface reactivity and adsorption sites of LiTaO and KTaO perovskite in the context of a heterogeneous catalytic process, such as the oxidation of styrene.