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

• 摘要：

  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 TiO islands on the positively poled (00-1) facet of PbTiO 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 PbTiO is inactive in visible light. This strategy may be applicable to various ferroelectric materials to produce unusual asymmetric micro-nano structures for excellent performance. Photocatalysis is intrinsically dependent on the synergy of three distinct steps, namely, light absorption, separation and transfer of photogenerated charge carriers, and surface catalysis. Ferroelectric materials such as tetragonal PbTiO with a spontaneous polar field as light absorbers have unique directional transport of photogenerated electrons and holes in the bulk along the ferroelectric field so that the electrons and holes can reach different surfaces. Prior to inducing a catalytic reaction, the effective transfer of charge carriers from the ferroelectric photocatalyst to a suitable co-catalyst such as Pt is indispensable but usually limited by the large Schottky barrier between them. In this study, the selective epitaxial growth of anatase TiO nano-islands on the positively poled (001¯) facet of PbTiO is demonstrated to be effective in fully addressing such a limitation and greatly improving the photocatalytic activity of ferroelectric photocatalysts. Selective chemical epitaxial growth of anatase TiO islands on the positively poled (001¯) facet of the ferroelectric PbTiO photocatalyst can significantly boost photocatalytic hydrogen and oxygen generation under both UV-visible light and visible light largely as a result of the greatly lowered Schottky barrier between PbTiO and co-catalyst Pt, promoting the charge transfer process between them. This strategy might be applied to modify various ferroelectric photocatalysts to produce unusual asymmetric micro-nano structures for excellent performance.

• 作者：

  刘刚    Ma Li    Lichang Yin    Wan Gedeng    Zhu Huaze    Zhen Chao    Yang Yongqiang    Liang Yan    Tan Jun    成会明    

• 刊名：

  Joule

• 在线出版时间：

  2018