α-Fe2O3 nanoplates: PEG-600 assisted hydrothermal synthesis and formation mechanism

Quasi-hexagonal α-Fe2O3 nanoplates with lateral sizes of 40–60 nm and thickness of ca. 10 nm were fabricated by a facile poly(ethylene glycol 600) (PEG-600) assisted hydrothermal technique in combination with calcination method. The final α-Fe2O3 nanoplates inherited perfectly the morphology of the preliminarily hydrothermal products with phases of dominant α-Fe2O3 and minor α-FeOOH. The platelets could be tailored from nano- to meso- and to micro-scale via adjusting PEG-600 quantities. An adsorption-extension-attachment model was proposed to explain the formation and growth mechanism of the platelets. The as-obtained α-Fe2O3 nanoplates exhibited a specific Langmuir surface area of 59 m2/g and a maximum N2 adsorption of 137.3 cm3/g at 1 atm. UV–vis measurement showed a strong absorption in a wide range from UV to visible light with a blue-shifting band gap of 2.33 eV due to the nanosize effect.

Research highlights▶ Quasi-hexagonal α-Fe2O3 nanoplates with lateral sizes of 40-60 nm and thickness of ca. 10 nm were successfully fabricated by a facile PEG-600 assisted hydrothermal and post heat-treated approach in high yield. ▶ The morphologies of α-Fe2O3 products can be easily tailored among “irregular particles-nanoplates-mesoplates-microplates” via adjusting the quantity of PEG-600. An asorption-extension-attachment model was proposed to explain the formation and growth mechanism of the plates. ▶ Adsorption-desorption measurement of α-Fe2O3 nanoplates showed a higher Langmuir and BET surface areas and the maximum adsorption than that of the mesoplates. UV-vis spectrum indicated a blue-shifting band gap.