The dissociative adsorption of methane oil variously oxidized Pd, Pt, and Pd-Pt surfaces is investigated using density functional theory as a step toward undemanding the combustion of methane on these materials. For Pd-Pt alloys, models of surface oxide structures are built on the basis of known oxides on Pd and Pt. The methane adsorption energy presents large variations depending oil the oxide structure and composition. Adsorption is endothermic on the bare Pd(111) metal surface is well as on stable (hill layer oxide structures Such as the (root 5 x root 5) surface oxide on Pd(100) and the PtO2-like oxide oil Pt(I 11) Instead, large adsorption energies are obtained For the (100) surface of bulk PdO, for metastable mixed Pd1-xPtxO4/3 oxide layers oil Pt(100), and for Pd-Pt(111) Surfaces covered with one oxygen monolayer In the latter case, we find a net thermodynamic preference for a direct conversion of methane to methanol, which remains adsorbed oil the oxidized Metal Substrates via weak hydrogen-bond interactions