Graphene Decoration for Gas Detection

Abstract

A comparison among the gas sensing properties of pristine graphene and graphene decorated with noble metal nanoparticles is herein investigated. Pristine graphene sheets are realized using the Liquid Phase Exfoliation method; noble metal decoration (namely platinum and palladium) is performed by a facile one-step chemical procedure which relies on the reduction of metal precursor salts directly onto graphene surface. All the materials have been employed as chemical sensing layer in a conductometric structure and tested towards some key analytes of interest for environmental monitoring, namely NO2, NH3 and H2. The device based on pristine graphene exhibits a specific response to NO2, whereas the device based on palladium-decorated graphene is more sensitive towards hydrogen. The third typology of device, based on graphene functionalized with platinum, shows a poorly selective behaviour. Unexpectedly, thanks to the remarkable stability of the material, this apparent drawback can be profitably exploited and overcome by integrating the sensing devices into an array, which enables to discriminate hydrogen from ammonia.