Top-down fabrication of hematite mesocrystals with tunable morphologies

Novel hematite mesocrystals including hierarchical microcones and microdiscs were synthesized by selective HCl etching of hematite pseudocubes. These porous mesocrystals adopting a single-crystal-like structure consist of radially aligned α-Fe₂O₃ nanorods, which elucidates the intrinsic mesocrystalline structure of the initial hematite pseudocubes. The hematite mesocrystals exhibited enhanced visible-light photocatalytic activity and high Cr(vi) removal capacity. This result provides an effective top-down approach towards mesocrystals with tunable morphologies and architectures.