Ge alloying also has a big impact on the cluster geometry. Contrary to Pt clusters, a repulsive interaction between Ge and phosphorene is visible which pushes the Ge atoms upwards; no Ge-P bonds are observed. This has two consequences. First, the Ge atoms are available to bridge the linear Pt clusters, as observed in Pt3Ge and Pt2Ge2 shown in Figure . Second, high Ge concentrations will result in a poor Pt-Ge mixing (e.g., see Pt4Ge4 on Figure ), which may remove the promoting effects of Ge on Pt. Indeed, as Ge concentration increases, Pt and Ge clusters tend to form two separate phases, i.e., one made of Pt and the other one of Ge, which is avoiding contact with the surface. This is in stark contrast with the behaviour in gas-phase. As a consequence, a medium/large amount of Ge could potentially block the active sites.