Germanium was recently suggested by Jimenez-Izal et al. as a dopant for small Pt clusters to inhibit coking and sintering under conditions of alkane dehydrogenation. Supported Pt2Ge clusters were predicted to be more sinter-resistant than Pt3, Pt2Sn, and Pt2Si clusters, and to be highly active for ethane dehydrogenation to ethylene, while resisting deeper dehydrogenation to form coke. Although density functional theory (DFT) simulations were promising, previous experimental work on Ge-containing catalysts was not always successful. For example, several studies found that activity for dehydrogenation of cyclohexane was substantially lower for PtGe catalysts than for analogous Pt catalysts . Note, however, that these studies focused on catalysts with particle sizes much larger than the sub-nano clusters examined here. Here we report a novel approach to improving cluster catalyst stability, in which self-limiting coking converts the alumina-supported PtnGex catalyst clusters to a PtnGexCy form that is catalytically active and thermally and chemically stable.