out to obtain the optimal catalyst compositions that will boost the catalytic activity. Except for the graphene-based supports, the rest of the 2D materials considered in this work are very effective in anchoring the clusters. Indeed, a very important MSI is observed which translates into the complete wetting of the cluster to the surface and a huge support-to-cluster charge transfer and binding energy. Pt clusters on germanene and SmSI are encapsulated by Ge and I atoms, suggesting that these supports are capable of inducing SMSI effects. On phosphorene Eads increases with the size of Ptn, and decreases with Ge concentration. Moreover, Ge avoids surface contact by sitting on top of the clusters. Consequently, high Ge contents might lead to the blocking of active sites. On the rest of the 2D materials, Ge alloying weakens the cluster-support interaction too. However, when PtGe is supported on silicene and germanene the Eads values are remarkably large, suggesting that these monolayers could be used to hold PtGe catalysts. Importantly, all the supports except phosphorene allow a favorable Pt-Ge mixing. Furthermore, cluster deposition is demonstrated to be an effective method to reduce the band gap of the support and facilitate electron transport.