CO Sensing Properties of Nanostructured La0.8Sr0.2CoO3 Sensors Synthesized by EDTA-Glycol Method

We report a simple method for the preparation of pure LaCoO3 and La1-xSrxCoO3 (x = 0.1, 0.2 and 0.25) nanostructures by the EDTA-Glycol method. The final powders obtained by this method have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements. The gas sensitivity of pure and Sr doped LaCoO3 samples were investigated for CO, NH3, H2 and LPG. La0.8Sr0.2CoO3 powders (sample GIII) calcined at 6500C, exhibited a good sensor response towards CO gas at 2500C. On impregnation of 1 wt.% Pd over sample GIII, the operation temperature reduced to 2000C with a significant rise in sensitivity. The response time also decreases from about 3.5 min for sample GIII to less than 2.5 min for the Pd loaded element. The electronic interaction between Pd and metal oxide semiconductor is proposed to account for the sensitization effect

Structural Properties of Nanosized NiFe2O4 for LPG Sensor

Nanocrystalline NiFe2O4 has been synthesized by sol-gel citrate method. The synthesized powder was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). As found from the XRD line broadening, the crystallite size of the powder was found to be 40 nm. The gas sensing properties were studied for reducing gases such as LPG, CH4, CO and NH3. It was observed that the nanosized NiFe2O4 shows high sensitivity for LPG at an operating temperature 300 oC. Pd incorporation in NiFe2O4 results in a decrease in operating temperature by 100 oC and improves the sensing characteristics in terms of response time