Ferroelectric polarization effect on surface chemistry and photo-catalytic activity: A review

The current efficiency of various photocatalytic processes is limited by the recombination of photogenerated electron–hole pairs in the photocatalyst as well as the back-reaction of intermediate species. This review concentrates on the use of ferroelectric polarization to mitigate electron–hole recombination and back-reactions and therefore improve photochemical reactivity. Ferroelectric materials are considered as wide band gap polarizable semiconductors. Depending on the surface polarization, different regions of the surface experience different extents of band bending and promote different carriers to move to spatially different locations. This can lead to some interesting interactions at the surface such as spatially selective adsorption and surface redox reactions. This introductory review covers the fundamental properties of ferroelectric materials, effect of an internal electric field/polarization on charge carrier separation, effect of the polarization on the surface photochemistry and reviews the work done on the use of these ferroelectric materials for photocatalytic applications such as dye degradation and water splitting. The manipulation of photogenerated charge carriers through an internal electric field/surface polarization is a promising strategy for the design of improved photocatalysts.