Hollow Anatase TiO2 Single Crystals and Mesocrystals with Dominant {101} Facets for Improved Photocatalysis Activity and Tuned Reaction Preference

Faceting photocatalysts has attracted increasing interest to improve photocatalytic activity by optimizing surface charge carrier separation/transfer. In principle, a high photocatalytic activity is co-contributed by both high surface separation/transfer and low bulk recombination of charge carriers. However, little effort focuses on lowering bulk recombination of charge carriers in faceted photocatalysts. In this work, we report the synthesis of hollow anatase TiO2 single crystals and mesocrystals with dominant (101) facets by a new route with PO43-/F- as morphology controlling agent. It is found that with respect to solid crystals, being hollow crystals and mesocrystals can substantially improve photocatalytic activity (O-2/H-2 evolution from water splitting, CH4 generation from photoreduction of CO2) as a result of the synergistic effects of shortened bulk diffusion length of carriers for the decreased bulk recombination and increased surface area. Furthermore, the photocatalysis reaction preference toward O-2 and H-2 evolution from water splitting can be tuned.