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High-Energy Faceted SnO2-Coated TiO2 Nanobelt Heterostructure for Near-Ambient Temperature-Responsive Ethanol Sensor

Chen, Guohui, Ji, Shaozheng, Li, Haidong, Kang, Xueliang, Chang, Sujie, Wang, Yana, Yu, Guangwei, Lu, Jianren, Claverie, Jerome, Sang, Yuanhua, Liu, Hong
ACS Applied Materials & Interfaces 2015 v.7 no.44 pp. 24950-24956
ambient temperature, ethanol, gases, oxidation, oxygen, tin, tin dioxide, titanium dioxide
A SnO₂ gas sensor was prepared by a two-step oxidation process whereby a Sn(II) precursor was partially oxidized by a hydrothermal process and the resulting Sn₃O₄ nanoplates were thermally oxidized to yield SnO₂ nanoplates. The SnO₂ sensor was selective and responsive toward ethanol at a temperature as low as 43 °C. This low sensing temperature stems from the rapid charge transport within SnO₂ and from the presence of high-energy (001) facets available for oxygen chemisorption. SnO₂/TiO₂ nanobelt heterostructures were fabricated by a similar two-step process in which TiO₂ nanobelts acted as support for the epitaxial growth of intermediate Sn₃O₄. At temperatures ranging from 43 to 276 °C, the response of these branched nanobelts is more than double the response of SnO₂ for ethanol detection. Our observations demonstrate the potential of low-cost SnO₂-based sensors with controlled morphology and reactive facets for detecting gases around room temperature.