Molecular Catalysis at Polarized Interfaces Created by Ferroelectric BaTiO3 (Postprint)
Journal Article - Open Access
STANFORD UNIV CA STANFORD United States
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The local environment at highly polarized solid-liquid interfaces provides a unique medium for chemical reactions that could be exploited to control selectivity of non-Faradaic reactions. Polarized interfaces are commonly prepared by applying a voltage to an electrode immersed in an electrolyte solution, but it is challenging to achieve high surface charge densities while suppressing undesired Faradaic processes. Ferroelectric materials have permanent high surface charge densities that arise from the dipole moments of ferroelectric domains and can be used to create polarized solid-liquid interfaces without application of a voltage. The effects of ferroelectric BaTiO3 materials on the selectivity of catalytic reactions were compared to the effects of a voltage-polarized electrode-electrolyte interface. The reactions investigated were a Rh porphyrin-catalyzed intramolecular carbene rearrangement and a Au-catalyzed arylalkynyl sulfoxide rearrangement. In both cases, the addition of ferroelectric BaTiO3nanoparticles to the reaction solutions changed the product ratios in the same direction and by a similar magnitude as performing the reactions at an electrode-electrolyte interface polarized by a voltage. In contrast, non-ferroelectric TiO2, CaTiO3, or SrTiO3 nanoparticles had little or no effect on the product ratios. The results demonstrate that colloidal suspensions of BaTiO3 nanoparticles effectively act as a dispersible polarized interface that can influence the selectivity of catalytic reactions in a similar manner to an electrically polarized electrode electrolyte interface.