Selective Chemical Epitaxial Growth of TiO2 Islands on Ferroelectric PbTiO3 Crystals to Boost Photocatalytic Activity

Integrating a semiconducting light absorber with an appropriate co-catalyst appears almost indispensable for photocatalytic solar fuel generation. Although ferroelectric materials with spontaneous electrical polarization are considered promising light absorbers with the ability to induce oppositely directed transport of photogenerated electrons and holes in the bulk, their applications are intrinsically restricted by the large Schottky barrier at the interface of the ferroelectric material and the co-catalyst, which has a larger work function. Here, we demonstrate that, by selective chemical epitaxial growth of anatase TiO2 islands on the positively poled (00-1) facet of PbTiO3 single-crystal particles to form an atomically smooth interface with a small potential difference, the material shows significantly improved photocatalytic hydrogen and oxygen generation under both UV-visible and visible light, while the island-free PbTiO3 is inactive in visible light. This strategy may be applicable to various ferroelectric materials to produce unusual asymmetric micro-nano structures for excellent performance.