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Room temperature NO2 sensing performance of a-C-decorated TeO2 nanowires

2022; Elsevier BV; Volume: 363; Linguagem: Inglês

10.1016/j.snb.2022.131853

1873-3077

Wansik Oum, Ali Mirzaei, Tanveer Hussain, Jae Hoon Bang, Seungmin Han, Ka Yoon Shin, Dong Yu, Sukwoo Kang, Thanayut Kaewmaraya, Sang Sub Kim, Hyoun Woo Kim,

Transition Metal Oxide Nanomaterials

TeO2 is a semiconducting metal oxide that is not popular for sensing studies due to its poor sensing performance in its pristine form. To enhance its sensing performance, we deposited amorphous carbon (a-C) on its surface. We first synthesized TeO2 nanowires using a thermal evaporation method, and then we deposited an a-C layer on them by a simple procedure using a flame carbon vapor deposition technique. We showed that the a-C-decorated sensor had a lower optimized sensing temperature (26 °C) relative to the pristine TeO2 sensor (50 °C) and presented a higher sensitivity to NO2 gas. The maximum responses to NO2 (10 ppm) were 1.918 and 1.468 for a-C-decorated and pristine TeO2 nanowires, respectively. Furthermore, the a-C-decorated sensor indicated outstanding selectivity toward NO2. The high performance of a-C-decorated sensor was results of its higher surface area created by the bumpy carbon layer on the surface of TeO2 nanowires as well as the electronic sensitization due to the a-C layer. We also confirmed NO2 sensing behaviors of bare and a-C-decorated TeO2 nanowires using density functional theory (DFT) calculations, where calculated binding energies between NO2 and the sensing layer were stronger for NO2 and a-C-decorated TeO2 nanowire gas sensor relative to pristine gas sensors. The present approach for enhancing the sensing of TeO2 nanowires can be extended to other sensor systems as a simple, inexpensive strategy to improve sensor performance.