The aim of this thesis project is to investigate the possibility of decorating graphene material with nanoparticles to enhance performance of graphene-based gas sensors. In recent years, graphene has attracted particular attention in the field of gas sensing. The affinity of such material with numerous gas species, the ability to operate at room temperature and the large specific surface area are just some of the characteristics that make it a promising material. However, the use of graphene has some limitations that make it difficult to be exploited in commercial sensors. Among these limitations: the low selectivity towards different analyte, the difficult of the signal to reach saturation and to return at the initial level during the restoration phase.