Atmospheric Pressure Solvothermal Synthesis of Nanoscale SnO 2 and Its Application in Microextrusion Printing of a Thick-Film Chemosensor Material for Effective Ethanol Detection.

The atmospheric pressure solvothermal (APS) synthesis of nanocrystalline SnO 2 (average size of coherent scattering regions (CSR)-7.5 ± 0.6 nm) using tin acetylacetonate as a precursor was studied. The resulting nanopowder was used as a functional ink component in microextrusion printing of a tin dioxide thick film on the surface of a Pt/Al 2 O 3 /Pt chip. Synchronous thermal analysis shows that the resulting semiproduct is transformed completely into tin dioxide nanopowder at 400 °C within 1 h. The SnO 2 powder and the resulting film were shown to have a cassiterite-type structure according to X-ray diffraction analysis, and IR spectroscopy was used to establish the set of functional groups in the material composition. The microstructural features of the tin dioxide powder were analyzed using scanning (SEM) and transmission (TEM) electron microscopy: the average size of the oxide powder particles was 8.2 ± 0.7 nm. Various atomic force microscopy (AFM) techniques were employed to investigate the topography of the oxide film and to build maps of surface capacitance and potential distribution. The temperature dependence of the electrical conductivity of the printed SnO 2 film was studied using impedance spectroscopy. The chemosensory properties of the formed material when detecting H 2 , CO, NH 3 , C 6 H 6 , C 3 H 6 O and C 2 H 5 OH, including at varying humidity, were also examined. It was demonstrated that the obtained SnO 2 film has an increased sensitivity (the sensory response value was 1.4-63.5) and selectivity for detection of 4-100 ppm C 2 H 5 OH at an operating temperature of 200 °C.