Pt4Ge/alumina clusters are found to strongly bind and activate ethane on all thermally accessible isomers (Fig. ), and there are well over 50 configurations for C2H6-Pt4Ge/alumina with energies below 0.4 eV, i.e., with non-zero thermal populations at 700 K. All of the low-lying configurations appear to activate ethane, as shown by C-H bond elongations ranging from 1.140 Å to 1.158 Å, compared to the un-activated C-H bond length of 1.09 Å. Figure illustrates two reactant configurations and gives energies (horizontal lines) for a dozen more. The two illustrated are built on the GM and on the second local minimum (LM2) for the bare Pt4Ge cluster. The LM2-based structures are singled out for reasons that will be made clear shortly. Once adsorbates bind to LM2, the structures are labeled LM', because their thermal accessibility is changed by the binding of adsorbates. For all the lowest-energy configurations, the activation barriers for breaking the first C-H bond are found to be ≤ 0.4 eV, well below the energy for desorption of ethane from the clusters (≤ 0.6 eV, see Fig. and). Thus, DFT shows that ethane should bind to all isomers of Pt4Ge/alumina, and dehydrogenate in preference to desorbing. Another factor that tends to promote dehydrogenation is that the H atom products readily recombine and desorb as H2 at moderate temperatures, as shown in Fig. .