Bilayer cascade of WO <sub>3</sub> nanofibers/Ag@CeO <sub>2</sub> nanosheets for ppb‐level xylene detection under the catalysis‐gas sensitivity synergistic mechanism
Ding Wang, Ruijie Qin, Jiejie Yu, Jinwu Hu, Wenhui Zhang, Hui Xu, Jingcheng Xu, Qiao-Bo Liao, Huijun Li, Xu‐Hui Wang
Abstract
Abstract The semiconductor gas sensors used for xylene gas detection in real time has been restricted by the inadequate sensitivity and selectivity. Constructing a bilayer cascade sensor with the catalysis‐gas sensitivity synergistic is considered as an effective solution. Herein, the Ag@CeO 2 nanosheets are synthesized by heat treating the Ag@Ce‐MOF, which synthesized via solvothermal method. The morphological evolution of cerium metal–organic framework (Ce‐MOF), regulated by Ag ions, is investigated, and the transformation mechanism is proposed. The bilayer sensors were constructed by using WO 3 nanofibers, prepared via the electrospinning method, as the sensitive layer and the Ag@CeO 2 nanosheets as the catalytic layer, respectively. The bilayer sensors exhibit remarkable performance in response to xylene. The response value ( R a / R g ) of WO 3 /Ag@CeO 2 sensor to 10 ppm xylene gas reaches 32.13 at the operating temperature of 160 °C. Additionally, the sensor displays an exceptional response to even trace amounts of xylene, as low as parts per billion (ppb). The catalysis‐gas sensitivity synergistic mechanism was elucidated by capturing catalytic intermediates using online mass spectrometry. These findings provide a novel strategy for benzene series (BTEX) sensor and offer a novel approach to prepare two‐dimensional Ce‐MOF and its derived materials with tailored properties.