Synthesis, characterization and vapour sensing properties of nanosized ZnFe2O4

In recent years, there has been a renewed interest on spinel ferrites for their remarkable versatile applications. Among AFe(2)O(4), zinc ferrite (ZnFe2O4) has gained special importance due to its application in gas sensing, drug delivery and magnetic resonance imaging. Nanocrystalline powder of ZnFe2O4 with average size of 25-30 nm was synthesized using citrate-gel method. Thermogravimetric analysis and XRD confirmed the formation of nanocrystalline ZnFe2O4 at 400 degrees C. The band appearing below 700 cm(-1) in the FTIR spectrum confirmed the presence of Zn(Fe-O) group. Microstructural investigation was done on SEM and TEM. The response of ZnFe2O4 towards alcohol and acetone vapour at 350 degrees C was studied. The sample showed n-type conductivity with excellent vapour sensitivity

Nanocrystalline gallium ferrite: A novel material for sensing very low concentration of alcohol vapour

Nanocrystalline orthorhombic gallium ferrite (GFO) has been synthesized by a sol gel method. The synthesized powder has been characterized by TG/DTA, XRD, TEM, FTIR and nitrogen adsorption isotherm. In the present study we report an excellent ethanol vapour sensitivity of nanocrystalline GaFeO3 at concentrations down to 1 ppm making the sensors suitable for application in food industries. Interestingly in contrast to the market available consumers breath analyser based on tin dioxide, GaFeO3-based sensor is immune to moisture (present in breath) and acetone vapour (an interfacing agent for diabetics). Such gallium ferrite based sensors can be used to make potential interference free breath analyser for real-life applications. In addition, such sensors being highly selective and do not show any cross-sensitivity towards moisture, methanol and carbon monoxide like those based on tin dioxide. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved