To our surprise, the addition of Ge shifts ΔGOOH* to more positive values for all supports, approaching the ideal value of 3.69 eV. Notwithstanding, in the cases where O* binds to Ge, the corresponding ΔGO* shifts to more exergonic values, as in Pt5Ge5 deposited on 5-8-5-DV, 2H-MoS2 and SmSI. In this latter, O* binds more strongly to Ge than to Sm (ΔGO* = -0.72 eV vs ΔGO* = -0.36 eV). In contrast, ΔGOH* follows the opposite trend upon alloying: Ge binds OH* less strongly than Sm (ΔGOH* = 0.23 eV vs ΔGOH* = -0.31 eV), making Ge a more suitable site for OH* hydrogenation.