UV excited gas sensing SnO2-ZnO aerogels to ppb-level ethanol detection

Gas-sensing materials that can detect ultra-low gas concentration at ppb level have attracted widespread attention. In order to reduce minimum detectable limit, on the one hand, we synthesized 3D SnO2-ZnO aerogels by two-step reactions and annealing process. On the other hand, we utilized UV light to motivate lower response concentration. SnO2-ZnO aerogels exhibit ultra-low response concentration as 10 ppb to ethanol at 300? under UV irradiation. In this condition, their response time (-2 s), recovery time (-37 s) and stability (within 14 days) also represent that SnO2-ZnO aerogels are suitable for gas sensors. Lastly, ethanol-sensing mechanism indicates that the following aspects help SnO2-ZnO aerogels to detect ultra-low ethanol concentration under UV irradiation: (i) adequate mesoporous structure increases active sites, facilitates ethanol transfer and improves UV utilization; (ii) tensile strain enables aerogels to absorb more abundant UV energy and then produce available photo-electrons in ethanol atmosphere; (iii) well-planned bandgap structure (SnO2 grain, ZnO grain and n-n heterojunction) can also provide more photo-electrons to reduce resistance in ethanol atmosphere.

Automated summary

This study successfully achieved ultra-low response concentration detection of ethanol by synthesizing 3D SnO2-ZnO aerogels and utilizing UV light to motivate lower response concentration. The research also indicates that SnO2-ZnO aerogels exhibit fast response time, short recovery time, and good stability under UV irradiation conditions, making them suitable for gas sensors.