An ultraselective and ultrasensitive TEA sensor based on α-MoO 3 hierarchical nanostructures and the sensing mechanism

• Published in: CrystEngComm 2015, Vol.17 (34), p.6493-6503
• Main Authors: Sui, Lili, Song, Xiaoxiao, Cheng, Xiaoli, Zhang, Xianfa, Xu, Yingming, Gao, Shan, Wang, Ping, Zhao, Hui, Huo, Lihua
• Format: Article
• Language: English
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/C5CE00693G

Flower-like, hierarchically nanostructured α-MoO 3 was successfully synthesized via a one-step, template-free solvothermal route. Morphological characterization demonstrated that the nanostructures were hierarchically assembled by overlapping single-crystalline nanobelts with exposed (010) facets. These nanobelts, with a width of 40–60 nm and a thickness of 20–30 nm, grew radially from the core of the α-MoO 3 flower. The growth mechanism of the α-MoO 3 flower was speculated to be through oriented self-attachment of the nanobelts. The gas sensor based on α-MoO 3 flowers showed an excellent sensing performance towards triethylamine (TEA) in terms of a high response (931.2) and excellent selectivity towards 10 ppm TEA. Especially, the detection limit was down to 0.001 ppm at a working temperature of 170 °C. The surface status of the α-MoO 3 flowers before and after exposure to TEA at 170 °C was investigated by XPS. The probable oxidization product of TEA was analyzed by GC-MS. The MoO 3 sensing mechanism could be interpreted as the transformation of triethylamine to vinylamine through two catalytic oxidation processes: the reactions with chemisorbed oxygen, and with lattice oxygen. The possibility relating to an enhanced gas sensing response of the three-dimensional (3D) flower-like α-MoO 3 was discussed.