Epitaxial heterostructures are of particular interest owing to their fascinating properties for wide applications in energy, environment and electronic devices. The understanding of epitaxial growth in solution phase, however, remains a fundamental challenge to realize the rational synthesis of heterostructures. Here we report that anatase TiO₂ can epitaxially grow on the selective polar surface of single-crystal and single-domain ferroelectric PbTiO₃ nanoplates. The interplay of ferroelectric polar surface and corresponding ion adsorptions on them has been revealed experimentally and theoretically to determine the epitaxial growth mode, giving rising to zero-dimensional (0D)/two-dimensional (2D) and 2D/2D heterostructures. A combination of experimental and theoretical calculations indicate that the resulting heterostructures adopt a polarization-dependent photocatalytic performance under visible light irradiation, including hole-based photodegradation and electron-based hydrogen evolution reaction (HER) of water splitting. Such findings allow investigation of the potential of ferroelectric polarization towards tuning epitaxial growth and functionality of heterostructures.

外延异质结构由于其引人入胜的特性而特别受到关注，因为它们在能源，环境和电子设备中的广泛应用。然而，对溶液相中外延生长的理解仍然是实现异质结构合理合成的根本挑战。在这里我们报告锐钛矿型TiO ₂可以在单晶和单畴铁电PbTiO ₃的选择性极性表面上外延生长纳米板。已经通过实验和理论揭示了铁电极性表面与相应离子吸附的相互作用，以确定外延生长模式，从而产生了零维（0D）/二维（2D）和2D / 2D异质结构。实验和理论计算的组合表明，所得的异质结构在可见光辐射下具有偏振相关的光催化性能，包括基于空穴的光降解和基于电子的水分解氢生成反应（HER）。这些发现允许研究铁电极化对调整外延生长和异质结构功能性的潜力。