Iron-oxide nanoparticles supported on sepiolite as a novel humidity sensor

In the present work, a new humidity sensor based on nanostructured hematite deposited by a wet chemical route on a low-cost natural inorganic phylosilicate (sepiolite) powder was obtained. The nanometric character of these particles has been evaluated by X-ray diffraction, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) and transmission electron microscopy. This material compacted as a pellet by uniaxial pressure with the corresponding interdigitated gold electrodes, was found to be very appropriate to operate as humidity sensor over a wide relative humidity (RH) range (5–98%).