Confinement Enrichment Effect in HoMS-BaTiO<sub>3</sub> Microwave Gas Sensors for the Detection of 10 ppb–0.55 v/v% Ammonia at Room Temperature
Jiahui Xu, Xianwang Yang, Ke Wang, Quan Jin, Xiaolong Wang, Geyu Lu
Abstract
The construction of ammonia gas sensors with wide detection ranges is important for exhalation diagnosis and environmental pollution monitoring. To achieve a wide detection range, sensitive materials must possess excellent spatial confinement and large active surfaces to enhance gas adsorption. In this study, an ammonia microwave gas sensor with a wide detection range of 10 ppb–0.55 v/v% at room temperature was fabricated by incorporating hollow multishelled-structured BaTiO 3 (HoMS-BaTiO 3 ). The effect of the number of shells and the quantity of the sensitive material on the gas-sensing performance was investigated, and two-layered HoMS-BaTiO 3 demonstrated the best response at high concentrations (0.15–0.55 v/v%). Conversely, single-layered HoMS-BaTiO 3 displayed outstanding performance at low concentrations (10 ppb–0.15 v/v%). The lower the quantity of the sensitive material, the higher the response. This study offers a method for preparing room-temperature ammonia sensors with a wide detection range and reveals the link between the structure and quantity of sensitive materials and gas-sensing performance.