Phase Formation Behavior And Hydrogen Sensing Characteristics Of Iron Oxide Nano-Particles Synthesized By Modified Pechini Route

Iron oxide nano-particles are synthesized from aqueous iron (III) nitrate solution through citric acid and ethylene glycol assisted modified Pechini route. Synthesized particles are calcined at 400 and 600 degrees C in air to achieve better crystallization. The phase formation behaviors of the dried and calcined powders are studied by analyzing the respective X-ray diffraction patterns. The particles calcined at 600 degrees C are identified as pure hematite phase. However, maghemite is found as impurity with the desired hematite phase in dried particles and their counterpart calcined at 400 degrees C. The chemi-resistive hydrogen sensing characteristics of the sensing elements prepared from the dried and calcined powders are investigated by varying the operating temperature of the sensor (275-350 degrees C) and concentration of hydrogen gas (250-1660 ppm). The study reveals that the synthesized iron oxide particles are promising for the detection of hydrogen gas.