Effects of size on the photocatalytic properties of high-index faceted pseudocubic and rhombohedral α-Fe2O3 nanocrystals

Abstract

Size-controlled and high-index faceted α-Fe₂O₃ nanocrystals with pseudocubic and rhombohedral morphologies were synthesized through the hydrothermal treatment of β-FeOOH at different pHs. The size effect on the photocatalytic oxygen evolution efficiency of high-index faceted α-Fe₂O₃ nanocrystals was investigated. Rhombohedral α-Fe₂O₃ (pH 6.0) exhibits an outstanding apparent quantum yield of 9.93% and an oxygen evolution efficiency of 20.3%, which can be attributed to the optimal size and high-indexed {104} planes. This work provides a new idea for the design of high activity water oxidation catalysts, through the size optimization of high-index faceted materials.