02395nas a2200253   4500008004100000022001400041245007600055210006900131260006900200300001200269490000800281520158200289653002501871653001001896653001501906653003001921653000801951653000801959653000801967100001901975700002001994700001802014856010902032       2011                        eng d  a0925-400500aHighly sensitive and selective LPG sensor based on alpha-Fe2O3 nanorods0 aHighly sensitive and selective LPG sensor based on alphaFe2O3 na  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcMAR  a299-3060 v1523 a<p>The alpha-Fe2O3 nanorods were successfully synthesized without any templates by calcining the alpha-FeOOH precursor in air at 300 degrees C for 2 h and their LPG sensing characteristics were investigated. The alpha-FeOOH precursor was prepared through a simple and low cost wet chemical route at low temperature (40 degrees C) using FeSO4 center dot 7H(2)O and CH3COONa as starting materials. The formation of alpha-FeOOH precursor and its topotactic transformation to alpha-Fe2O3 upon calcination was confirmed by X-ray diffraction measurement (XRD). X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. The alpha-Fe2O3 nanorods exhibited outstanding gas sensing characteristics such as, higher gas response (similar to 1746-50 ppm LPG at 300 degrees C), extremely rapid response (similar to 3-4 s), relatively slow recovery (similar to 8-9 min), excellent repeatability, good selectivity and lower operating temperature (similar to 300 degrees C). Furthermore, the alpha-Fe2O3 nanorods are able to detect up to 5 ppm for LPG with reasonable response (similar to 15) at the operating temperature of 300 degrees C and they can be reliably used to monitor the concentration of LPG over the range (5-60 ppm). The experimental results clearly demonstrate the potential of using the alpha-Fe2O3 nanorods as sensing material in the fabrication of LPG sensors. Plausible LP G sensing mechanism of the alpha-Fe2O3 nanorods is also discussed. (C) 2010 Elsevier B.V. All rights reserved.</p>10aalpha-Fe2O3 nanorods10aFESEM10aLPG sensor10aSemiconductor gas sensors10aTEM10aXPS10aXRD1 aPatil, Dewyani1 aPatil, Virendra1 aPatil, Pradip  uhttp://library.ncl.res.in/content/highly-sensitive-and-selective-lpg-sensor-based-alpha-fe2o3-nanorods-002356nas a2200241   4500008004100000022001400041245010200055210006900157260006900226300001200295490000800307520148900315653002301804653003001827653002001857653003301877653000801910100001901918700002001937700001801957700001801975856012101993       2014                        eng d  a0925-400500aHumidity-sensing studies of cerium oxide nanoparticles synthesizedby non-isothermal precipitation0 aHumiditysensing studies of cerium oxide nanoparticles synthesize  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcNOV  a229-2380 v2033 a<p>We report the fabrication of a highly sensitive and fast humidity sensor based on cerium oxide (CeO2) nanoparticles, which were prepared at low cost via a simple non-isothermal precipitation method. The asprepared CeO2 nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy( TEM) and the results indicated the formation of face centered cubic phase of CeO2 with average crystallite size of approximately 10-12 nm. Humidity sensors based on CeO2 nanoparticles exhibit high and linear response within the whole relative humidity (RH) range of 11-97% at an operating frequency of 60 Hz. The corresponding impedance changes by approximately three orders of magnitude within the entire humidity range from 11% to 97% RH. The response and recovery times are about 2-3 and 9-10 s, respectively, when RH was switched between 11% and 97%. Furthermore, the sensors also show relatively small hysteresis, excellent reproducibility, long term stability and broad range of operation (11-97% RH). The complex impedance spectra of the sensor at different RHs and the equivalent circuit were analyzed to explore the humidity-sensing mechanism. This study demonstrates that the CeO2 nanoparticles prepared by non-precipitation method can be used as the humidity-sensing material for the fabrication of humidity sensors. (C) 2014 Elsevier B. V. All rights reserved.</p>10aCeO2 nanoparticles10aComplex impedance spectra10ahumidity sensor10aNon-isothermal precipitation10aTEM1 aKhadse, V., R.1 aThakur, Sharada1 aPatil, K., R.1 aPatil, Pradip  uhttp://library.ncl.res.in/content/humidity-sensing-studies-cerium-oxide-nanoparticles-synthesizedby-non-isothermal-0