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

Abstract

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, SnO2QDs/rGO (0.5 wt%) heterostructure sensors exhibit the highest sensitivity especially to formaldehyde at room temperatures (RT) and ethanol at 220 °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 °C. The high sensitivity is not only attributed to the reaction active center which provided by the heterojunctions between SnO2QDs and rGO, but also derived from effective electron transfer on the interface between SnO2QDs and rGO via SnOC bonds. In particular, for typical n-type semiconducting behavior, electrons transfer from rGO to SnO2QDs 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.