Space-Confined seeding and growth of ordered arrays of TiO₂ hierarchical nanostructures

Here, we report a facile approach to fabricate large area ordered arrays of TiO₂ hierarchical nanostructures through space-confined seeding and growth on inverted pyramid templates. The mechanisms of space-confined seeding and growth have been systematically explored and studied. The drying TiO₂ seed precursor solution prefers to accumulate on the narrow structures including the centre and edges of the inverted pyramid structures, which facilitates to reduce the free energy of the precursor solution surface and form crystal seeds. Followed by hydrothermal treatment, selective growth of TiO₂ hierarchical nanostructures on desirable locations, such as only on the centre, only on the edges, or on the entire surface of the inverted pyramid templates, can be achieved. In addition, the growth temperature, duration and solvents affect the morphology of TiO₂ hierarchical nanostructures. This work may provide a universal approach to obtain ordered arrays of metal oxide (e.g. ZnO and MnO₂, etc.) nanostructures for applications in optics, electrics, energy, and catalysis.