Another common alternative developed to enhance the lifetime of platinum is the use of promoters. The role of the dopants is to alter the geometric and electronic properties of Pt to boost the stability of the catalyst and selectivity of catalytic reactions. Sn is by far the most widely used alloying agent for platinum. The addition of Sn into Pt increases the barriers for C-H and C-C bond cleavage, improving the selectivity of the catalyst while maintaining reasonable activity. Other promoters for platinum are Zn, Ir, Si, B, Cu, and Ga, which have recently been implemented Industrially. Germanium too has been tested as a promoter for Pt in reactions such as naphtha reforming or larger alkane and cycloalkane dehydrogenation reactions. In the past, we predicted that germanium could be an adequate alloying agent to tune the selectivity and sintering resistance of Pt sub-nanoclusters in the ethane dehydrogenation reaction. This finding was later proven experimentally. However, given methods of preparation access only specific Pt:Ge stoichiometries. For example, in the ALD-like process in Ref. 31, Ge is delivered to supported Pt clusters in the form of a chloride, and this method yields an approximate 4:1 ratio of Pt to Ge. If the conditions of synthesis and/or precursors are changed, other stoichiometries could be accessed. It is therefore fundamentally interesting whether or not the Ge content in the cluster or nanoparticle is a lever of control of the nanocluster activity and selectivity. In this contribution we show that the Ge content affects activity and selectivity of the MgO-supported PtGe cluster catalysts, and rationalize the effect through electronic structure. Activity and selectivity are found to be conflicting trends as a function of Ge content in the cluster alloy, and there appears to be an optimal Pt:Ge ratio for the cluster catalyst performance.