The microkinetic simulations hint to a reduced CO and CO 2 poisoning dependence with increased Ge concentration. Pt 4 shows a bistable-like CO oxidation kinetics, in agreement with the literature. At low temperatures and/or high CO pressures it suffers from CO poisoning and CO 2 production drops drastically. On top of this, regardless of partial pressures, there is a constant CO 2 poisoning which also diminishes the reaction rates. Nevertheless, as the Ge concentration increases CO and CO 2 poisoning subside, until in Pt 4 Ge 3 the kinetic regime of severe CO poisoning is removed. A 4:3 Pt to Ge ratio changes the bistable kinetics of pure Pt and instead, a regime of fast CO 2 formation is obtained for all temperatures and pressures considered. CO 2 poisoning does not change in the same way with the Ge content as Pt 4 Ge 4 again shows some CO 2 poisoning. Thus, Pt 4 Ge 3 appears to be the optimal composition for the CO oxidation reaction.