Hierarchical hollow spheres composed of ultrathin Fe₂O ₃ nanosheets for lithium storage and photocatalytic water oxidation

Hollow hierarchical spheres self-organized from the ultrathin nanosheets of α-Fe₂O₃ were prepared by a simple process. These ultrathin nanosheet subunits possess an average thickness of around 3.5 nm and show preferential exposure of (110) facets. Their Li ion storage and visible-light photocatalytic water oxidation performance are tested. Such hierarchical nanostructures show high Li storage properties with good cycling stability and excellent rate capabilities. The water oxidation catalytic activity is 70 μmol h^-1 g^-1 for O₂ evolution under visible light irradiation and can be maintained for 15 hours. The structural features of these α-Fe₂O₃ nanocrystals are considered to be important to lead to the attractive properties in both Li storage and photocatalytic water oxidation, e.g. hollow interior, ultrathin thickness and largely exposed active facets.