Mesoporous WO3-TiO2 heterojunction for a hydrogen gas sensor

• DOI: 10.1016/j.snb.2021.130035
• Publication Date: 2021-04-24T04:55:40Z
• Authors: Hui Li; Chun-Han Wu; Yi-Cheng Liu; Shuo-Huang Yuan; Zong-Xian Chiang; Sam Zhang; Ren-Jang Wu
• Keywords: Hydrogen sensor

Abstract In this study, the WO3-TiO2 composite was fabricated as a hydrogen gas sensing element, and the heterojunction effect produced by the combination of WO3 and TiO2 was applied to hydrogen sensing under room temperature. X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive spectrometry, multipoint Brunner-Emmet-Teller model and transmission electron microscopy were used to examine the structure and morphology of the samples. The fabricated 4.0 wt% WO3-TiO2 possessing mesoporous structure was obtained with a high surface area of 109.8 m2/g. 4.0 wt% WO3-TiO2 -based sensor exhibited a high sense response of 5.26–10,000 ppm H2 with a short recovery time (5 s). The sensing time required for a complete single cycle was 182 s, a drop of 90.8 % from that for the TiO2-based sensor (1974s). Additionally, good stability, repeatability, and selectivity of the sensing material were observed. These experimental results reveal that the 4.0 wt% WO3-TiO2 heterojunction with mesoporous structure exhibits considerable potential as a hydrogen sensing element. A possible sensing mechanism was proposed.