Engineering a high energy surface of anatase TiO2 crystals towards enhanced performance for energy conversion and environmental applications

Anatase titanium dioxide (A-TiO2) is one of the most important functional materials and is widely used in various energy- and environmental related applications. Over the past decade, great efforts have been devoted to surface engineering of A-TiO2 crystals at the atomic level so as to fundamentally understand the relationship between the surface structure and their performance in practical applications. In this review, we briefly summarize recent important achievements on the control of specific surface structures of A-TiO2 crystals, focusing on facets with high surface energy (such as {001}, {100}, {101}) and their combinations. In addition, fascinating performances of A-TiO2 crystals enhanced by these high energy surfaces are examined and discussed through the perspectives of synergistic effects of different facets and surface adsorbates, with additional insights related to some contradictory results. Finally, we offer a summary and some perspectives on current challenges and promising directions in this emerging field. We believe that a comprehensive understanding of surface engineering of A-TiO2 crystals with regard to high energy facets will in the long term help us to rationally design functional nanomaterials with desired performances.