Preparation and gas sensing properties of γ-Fe2O3 nanopowders by solid-state grinding method at room temperature

gamma-Fe2O3 nanopowders have been synthesized by solid-state grinding method using Fe (NO3)(3) (.) 9H(2)O, NaOH and polyethylene glycol (PEG-200) as the starting material. The products have been characterized by FTIR, XRD, TEM and gas sensor measuring system. The result suggests that gamma-Fe2O3 with particle size about 410 run has been obtained when FeOOH calcined at 300 similar to 500 C for 1 h, while alpha-Fe2O3 can be obtained calcined at 600 degrees C for 1 h. At the same time, the sensor has high sensitivity and good selectivity to ethanol gas. Besides, alpha-Fe2O3 nanopowders can be produced when FeCl3 and polyethylene glycol (PEG-200) as the starting materials, indicating that different iron salt precursors and carbon chain length of polyglycol can evidently affect the final products.