Effect of ferroelectricity on solar-light-driven photocatalytic activity of BaTiO₃ - Influence on the carrier separation and stern layer formation

BaTiO₃ is used as a target catalyst to probe the influence of ferroelectricity on the decolorization of a typical dye molecule - Rhodamine B - under simulated solar light. We show that there is a 3-fold increase in the decolorization rate using BaTiO₃ with a high tetragonal content compared to predominantly cubic material. This is ascribed to the ferroelectricity of the tetragonal phase. The influence of ferroelectricity ensures a tightly bound layer of dye molecule and also acts to separate the photoexcited carriers due to the internal space charge layer. Both of these features act to enhance the catalytic performance. When nanostructured Ag is photochemically deposited on the surface of the BaTiO₃, we find a further increase in the reaction rate that gives complete decolorization of the dye in around 45 min.