Here, we present the effect of the graphene decoration with palladium nanoparticles (NPs) on the sensor sensitivity. A key aspect of this work is the method used for the decoration, that is made directly on pristine graphene obtained by the exfoliation of natural graphite in eco-friendly solvents at room temperature; the subsequent microwave treatment supplies the energy needed for the reduction of the palladium salt into palladium nanoparticles (PdNPs), which directly stick onto the pristine graphene surface. The PdNPs decoration results in a great improvement of the device response towards hydrogen, by definitively turning the high sensitivity versus nitrogen dioxide of the pristine material.