Detection of Ppb-level NO2 using mesoporous ZnSe/SnO2 core-shell microspheres based chemical sensors
Detection of ultralow concentrations of the hazardous gases is the major demand and challenge for the development of biosensors. A novel mesoporous ZnSe-core/SnO 2 -shell microspheres based chemiresistive-type sensor was fabricated for ppb-level NO 2 detection, and the theoretical detection limit is calculated to be 0.87 ppb. The as-fabricated sensor presents an excellent performance for low-concentrations of NO 2 up to 2.4 ppm and exhibits significantly higher response approximately 6.94 than those of pristine SnO 2 (∼2.86) and ZnSe based sensors (almost no response) to 2.4 ppm NO 2 at 160 °C. The response and recovery time of the core-shell microspheres based sensor are 64 s and 52 s, respectively, which are substantially improved compared to those of the pristine SnO 2 based sensor (∼149 s and ∼133 s). The sensor demonstrates a superior long-term stability with a deviation in the response of the sensor less than 5 % for one month, and a brilliant selectivity to several possible interferents. The significantly improved sensing performance could be attributed to the obtained mesoporous structures and the formed ZnSe/SnO 2 hybrid interfaces. It yields more active sites and promotes the electrons transferred between ZnSe and SnO 2 nanocrystals. The density functional theory (DFT) calculations are employed to reveal the potential transducing mechanisms.
危险品化学品经营许可证（带存储）