Unveiling the promoting effect of hollow double-shelled ZnSnO3/SnO2 heterojunctions on triethylamine sensing: Insights from in-situ FTIR and DFT calculation

In this work, hollow double-shelled ZnSnO 3 /SnO 2 heterojunctions are fabricated via a straightforward self-sacrificing template route. The crystal structure, microstructure, elemental composition, surface chemical states, optical properties and oxygen vacancies of the as-prepared materials are systematically characterized. Gas sensing tests reveal that the ZnSnO 3 /SnO 2 -2 sample exhibits a high response of 104.5 toward 100 ppm triethylamine (TEA) with a rapid response speed of 1 s at a relatively low operating temperature of 160°C, along with good selectivity, repeatability and long-term stability. The enhanced gas sensing mechanism is elucidated from the perspectives of electronic structure and surface reaction by combining density functional theory (DFT) calculations and in-situ Fourier transform infrared (FTIR) spectroscopy. Furthermore, preliminary monitoring of pork freshness during storage using the ZnSnO 3 /SnO 2 -2 sample demonstrates its potential in practical applications. This study provides a theoretical foundation and experimental support for the design of high-performance and low-power TEA gas sensors.