Mesoporous polycrystalline SnO<sub>2</sub> framework synthesized by direct soft templating method for highly selective detection of NO<sub>2</sub>
Nanotechnology, Dec 17, 2019
SnO2is one of the most-studied oxide materials for gas sensing applications. Investigations have ... more SnO2is one of the most-studied oxide materials for gas sensing applications. Investigations have shown that SnO2is sensitive to a wide range of gaseous compounds. However, the lack of selectivity of this material still requires an effective solution. A mesoporous polycrystalline SnO2framework was successfully synthesized using a soft templating method at ambient temperature and pressure. The prepared materials were characterized by using X-ray diffraction analysis, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, N2sorption tests, and X-ray photoelectron spectroscopy. Gas sensing analyses were performed on two batches of the material calcined at 400 and 500 °C. The materials are highly conductive at relatively low operating temperatures. The thermal annealing and operating temperature of the materials had significant effects on their gas sensing response and selectivity. The structure calcined at 400 °C showed very high selective response of 407 to 1 ppm NO2. The superior sensing performance of the obtained mesoporous SnO2 framework is attributed to its small crystal size of 4.5 nm, less than double the thickness of the critical electron depletion layer, high surface area of 89 m2∙g-1, and high pore volume of 0.12 cm3∙g-1.
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