Polarization-dependent epitaxial growth and photocatalytic performance of ferroelectric oxide heterostructures

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.