Polarization dependence of adsorption on ferroelectric BaTiO₃ surfaces

Mosha Zhao¹, D. Li², J. Garra², D. A. Bonnell², J. M. Vohs¹

¹Department of Chemical and Biomolecular Engineering, and
²Department of Materials Science and Engineering,
University of Pennsylvania Philadelphia, PA 19104

Abstract

The ability to manipulate the orientation of the dipoles in ferroelectric ceramics holds promise as a method to tailor the surface reactivity of these materials for specific applications. While over the last 50 years multiple studies have suggested that the orientation of ferroelectric domains may affect the energetics of adsorption on ferroelectric oxides, definitive evidence is still lacking. In this talk we will present the first unambiguous observations of differences in the energetics of adsorption on ferroelectric domains for adsorption of methanol and ethanol on barium titanate. Domain-dependent sticking coefficients are observed and indicate that the ferroelectric orientation alters the strength of the interaction of adsorbed species with the surface. Additionally, in ethanol TPD the desorption peak shapes and the relative product yields were found to be polarization dependent suggesting that ferroelectric polarization may also affect the intrinsic reactivity of the surface.

Speaker’s Bio - Mosha Zhao is currently a PhD candidate of chemical and biomolecular engineering in School of Engineering and Applied Science (SEAS), University of Pennsylvania. She is currently studying the ferroelectric polarization on surface reaction advised by Dr. John Vohs. She is the winner of the Catalysis Club of Philadelphia 2007 student poster competition.