Porous platelike hematite mesocrystals: synthesis, catalytic and gas-sensing applications

Abstract

Porous platelike α-Fe₂O₃ mesocrystals, composed of single crystalline nanoparticles, were prepared via a controlled solvent evaporation process in the presence of an ionic liquid [Bmim]Cl, which acted as both the solvent and the templating reagent. Compared to the Au/α-Fe₂O₃ (Fluka) catalyst, a significantly enhanced CO oxidation activity on the Au/porous platelike α-Fe₂O₃ mesocrystal catalyst was observed, which may be attributed to its more highly exposed (110) facet in the porous platelike α-Fe₂O₃ mesocrystals. Moreover, good repeatability and fast response and recovery times were obtained in an acetone sensitivity test conducted on the α-Fe₂O₃ nanoplates, produced via annealing of the porous platelike α-Fe₂O₃ mesocrystals at 400 °C. It is expected that this method is applicable to the synthesis of other inorganic functional oxides with unique structures and properties.