The study on the stability and activity of monometallic Pt and alloyed PtGe clusters supported on a set of 2D materials is divided into four parts. We begin by providing details on the stability of the clusters and propensity to sinter, both with respect to the adsorption strength to the substrate underneath. We then move on to the study of CO adsorption and resistance to CO poisoning. Later, we discuss the HOR performance. And finally, we carry out a mechanistic analysis of the ORR activity in terms of the stability of the intermediates within the CHE model. Each of this sections is at the same time divided into two subsections where on the one hand we investigate the role of size and composition, using phosphorene as a working example, and on the other hand, carry out a screening of the rest of 2D materials as support candidates, focusing only on Pt10 and Pt5Ge5 for the sake of comparison of the MSI effect.