@conference{
author = "Vojisavljević, Katarina and Savic, Slavica and Počuča-Nešić, Milica and Djokic, Veljko and Ribić, Vesna and Branković, Zorica and Branković, Goran",
year = "2019",
abstract = "In this contribution, the mesoporous SnO2 was fabricated via nanocasting,
where the hydrothermally processed silica KIT-5 with a high specific surface area of
610 m2/g and pore volume of 0.72 cm3/g was used as a hard template. Following the
two precursor loading/calcination steps of the wet impregnation process, the
appropriate amount of the Sn- precursor solution was used to fill up 15 % of the total
pore volume of the silica template with SnO2. This synthesis route with a template
etching by 2M NaOH solution resulted in nanocast SnO2 with Brunauer-Emmett-
Teller specific surface area of 33 m2/g, where SnO2 nanoparticles of 8–10 nm
formed the ordered domains along with fractions of disordered regions, as confirmed
by the transmission electron microscopy (TEM). Based on the Barrett-Joyner-
Halenda model from the desorption branch of the N2 adsorption/desorption
isotherms, the pore size of SnO2 is centered at 8.6 nm, demonstrating quite open and
accessible pore structure of the material. Wide-angle X-ray diffraction (XRD)
measurement confirmed the formation of the tetragonal SnO2 phase. Because of the
low Si content after the template etching (< 0.5%, confirmed by EDS analysis),
formation of substantial amounts of SnSiO3 can be excluded, and no evidence for
such phase was found in the XRD.
The as prepared SnO2 nanocast was further used to fabricate a few micron thick
film by the doctor blade technique on alumina substrate provided with interdigitated
Pt/Ag electrodes. The sensor response of the film towards humidity was tested
measuring the change of the complex impedance of the sample exposed to a humid
climate chamber environment with the relative humidity (RH) ranging from 40% to
90% at 25 °C and from 30% to 90% at 50 °C. The value of impedance measured at
100 Hz and 25 oC was reduced 132 times within the RH range of 40 % to 90 %,
while it tended to decrease in a moderate manner at 50 °C under the same frequency
and RH range. The film exhibited remarkably rapid response (4 s) and quick
recovery time (6 s) when exposed to RH change from 37% to 90% at 25 °C. Such a
fast response/recovery time and relatively low hysteresis of 4% observed under 50
% RH and 25 °C indicate the promising potentials of nanocasted SnO2 to be used as
an active layer for humidity sensors.",
publisher = "Institute for Multidisciplinary Research, University of Belgrade",
journal = "5th Conference of Serbian Society for Ceramic Materials",
title = "Humidity sensor based on mesoporous SnO2 fabricated via nanocasting technique",
pages = "66-66",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2311"
}
