A room temperature NH gas sensor based on a quartz crystal microbalance coated with a rGO-SnO composite film.

Novel QCM NH gas sensors made of reduced graphene oxide-SnO (rGO-SnO) composite films were fabricated using a one-pot technique, which is a fast and easy fabrication route that is useful for practical applications. The surface morphology and composition of the rGO-SnO composite films were analyzed using Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy coupled with energy-dispersive X-ray elemental mapping and transmission electron microscopy. On the basis of the microstructural observations, SnO connected to rGO sheets and naked rGO sheets were observed on the surface of the rGO-SnO composite films. The effects of the amount of added rGO sheets on the enhancement of the NH gas sensing properties of the rGO-SnO composite films were studied. The analysis of the adsorption dynamics (association constant) confirmed the higher sensitivity of the QCM NH gas sensor based on the rGO-SnO composite film than that of the sensor with the pristine SnO film.