O Abe Owen, Qiu Zanlin, R Jinschek Joerg, Gouma Pelagia-Irene
Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43202, USA.
Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43202, USA.
Sensors (Basel). 2021 Mar 1;21(5):1690. doi: 10.3390/s21051690.
The hexagonal WO3 polymorph, -WO3, has attracted attention due to its interatomic channels, allowing for a greater degree of intercalation compared to other WO3 polymorphs. Our research group has previously demonstrated -WO3 to be a highly sensitive gas sensing material for a flu biomarker, isoprene. In this work, the gas sensing performance of this polymorph has been further investigated in two distinct configurations of the material produced by different processing routes. The first sample was synthesized using Na2WO4·2H2O and showed (100) faceting. The second sample was synthesized using WCl6 and showed (001) faceting. The gas sensing response of the nanostructured films deposited using the (100) textured -WO3 sample 1 had a higher response to acetone at 350 °C. The (001) textured -WO3 sample 2 favored isoprene at 350 °C. The selectivity of the latter to isoprene is explained in terms of the dangling bonds present on the (001) facets. The tungsten and oxygen dangling bonds present on the (001) plane favor the adsorption of the isoprene molecule over that of the acetone molecule due to the oxygen containing dipole present in the acetone molecule.
六方相WO₃多晶型物，即β-WO₃，因其原子间通道而备受关注，与其他WO₃多晶型物相比，它具有更大程度的插层能力。我们的研究小组之前已证明β-WO₃是一种对流感生物标志物异戊二烯高度敏感的气敏材料。在这项工作中，通过不同加工路线制备的两种不同结构的该多晶型物的气敏性能得到了进一步研究。第一个样品使用Na₂WO₄·2H₂O合成，呈现（100）面。第二个样品使用WCl₆合成，呈现（001）面。使用具有（100）织构的β-WO₃样品1沉积的纳米结构薄膜在350℃时对丙酮的气敏响应更高。具有（001）织构的β-WO₃样品2在350℃时更有利于检测异戊二烯。后者对异戊二烯的选择性可根据（001）面上存在的悬空键来解释。由于丙酮分子中存在含氧偶极子，（001）面上存在的钨和氧悬空键有利于异戊二烯分子而非丙酮分子的吸附。
