Thermal decomposition of ferrous oxalate nanowires to porous nanowire-like α-Fe2O3 with a good gas-sensing properties

This research was performed to study a convenient, surfactant free and reducing approach for the synthesis of ferrous oxalate dihydrate (FeC2O4·2H2O) nanowires with a large aspect ratio using Fe(III) ions as iron source and ethylene glycol (EG) as reducing agent. X-ray diffraction, scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption isotherms, and thermal gravimetric analysis were utilized to reveal the structures. After calcination, mesoporous nanowire-like α-Fe2O3 with a large aspect ratio were prepared, which presents a good gas-sensing characteristics. The sensor response to 100 ppm ethanol was 25.7, combined with very short response and the recovery times at a working temperature of 240 °C. Furthermore, the obtained nanowire-like α-Fe2O3 sensor also exhibited a good long-term stability. The good properties were related the high content of the defect related oxygen species which revealed by the X-ray photoelectron spectroscopy.