The realization of an ultrasensitive multifunctional sensor through the formation of Sn-O-C bonds and favorable electron transfer direction

摘要

The combination of reduced graphene oxide (rGO) and SnO2 quantum dots (QDs) exhibits excellent sensitivities to formaldehyde, ethanol, acetone and methanol. Among the prepared sensors, SnO(2)QDs/rGO (0.5 wt%) heterostructure sensors exhibit the highest sensitivity especially to formaldehyde at room temperatures (RT) and ethanol at 220 degrees C. And sensitivities change from 215 to 4450 toward 0.4-40 ppm formaldehyde at RT and 34.8-403.3 toward 1-1000 ppm ethanol at 220 degrees C. The high sensitivity is not only attributed to the reaction active center which provided by the heterojunctions between SnO(2)QDs and rGO, but also derived from effective electron transfer on the interface between SnO(2)QDs and rGO via Sn-O-C bonds. In particular, for typical n-type semiconducting behavior, electrons transfer from rGO to SnO(2)QDs benefits gas sensitivity profoundly. The research of sensing mechanism and performance toward formaldehyde at room temperature and application as multi-functional gas sensors is crucial in practical application.