Cesium tungsten bronze nanostructures and their highly enhanced hydrogen gas sensing properties at room temperature

In this study, cesium tungsten bronze (Cs_xWO₃) a well-known metal oxide semiconductor and excellent photocatalyst and active photothermal material was used as a sensing material toward hydrogen for the first time. The Cs_xWO₃ nanorods were synthesized using a new hydrothermal method and examined through systematic material investigations. The synthesized Cs_xWO₃ nanorods were coated on SiO₂/Si substrates and subsequently fabricated laterally with multi-finger platinum (Pt)-based electrodes to test their gas detecting properties. The gas detecting property of the prepared material was studied toward very toxic hydrogen gas (10–500 ppm concentration). The gas sensing results demonstrate that the synthesized Cs_xWO₃ material has excellent gas sensing properties toward hydrogen (31.3%), which is overwhelmingly superior to as-prepared WO₃ (4.7%) due to its suitable electrical and optical properties at room temperature (RT). The selectivity results also indicate that the material has outstanding selectivity toward hydrogen compared with different gases such as ammonia and carbon dioxide. The critical features of this material are its high reliability, simple synthesis method, low humidity susceptibility, and high selectivity, making it viable for use in hydrogen sensors. Compared with the as-prepared WO₃, the adsorption capability and conductance of the Cs_xWO₃ surface induces active O₂ functional groups, significantly enhancing the gas sensing properties.