Operando DRIFT measurements on flame-spray-made Zn<inf>2</inf>SnO<inf>4</inf> nanoparticles based environmental sensors

Abstract

In this research, zinc stannate (Zn2SnO4) nanoparticles were synthesized using a single-step flame spray pyrolysis procedure. The material's properties were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Structural characterizations revealed that the nanoparticles had a spinel cubic nanocrystalline Zn2SnO4 phase. The sensitive layer of the sensor was fabricated by screen printing and exposed to various test gases, including CO, H2, VOCs (toluene, acetone, ethanol) and NO2 at 300 °C in both dry and humid conditions. Sensors produced from ZnO and SnO2 were used as references to compare the zinc stannate's performance. It was found that the stannate showed sensing behavior clearly distinct from the parent oxides. Diffuse reflectance infrared Fourier transform spectroscopy was used to gain insight into the surface reactions responsible for this sensing behavior of flame-spray-made Zn2SnO4 based sensor. The results revealed that mixed oxides offered desirable qualities not accessible using their parent oxides and should be more systematically examined for sensing.