The　catalytic　conversion　of　methane　(CH4)　has　garnered　significant　interest　due　to　its　potential　to　mitigate　the　greenhouse　effect　and　produce　high-value　chemicals.　In　this　work,　we　employ　density　functional　theory　(DFT)　calculations　to　investigate　the　performance　of　TM-doped　Ag(111)　dilute　alloys　in　CH4　activation.　The　results　demonstrate　that　Rh-　and　Pt-doped　Ag(111)　single-atom　alloys　(SAAs)　exhibit　high　activity　for　direct　CH4　activation,　while　Cr-,　Mn-,　and　Cu-doped　SAAs　display　activity　in　oxygen　(O2)　dissociation　rather　than　CH4　activation.　However,　the　pre-adsorption　of　an　oxygen　atom　(O*)　is　found　to　inhibit　CH4　activation　on　Rh-　and　Pt-doped　Ag(111)　surfaces,　while　promoting　it　on　Au-,　Cu-,　Pd-,　Mn-,　and　Cr-doped　Ag(111)　surfaces.　Electronic　structure　analysis　reveals　the　existence　of　a　distinct　two-site,　five-center　transition　state　(TS)　in　the　O*-assisted　C–H　activation　pathway,　where　dipole–dipole　interactions　play　a　crucial　role　in　stabilizing　the　TS.　Furthermore,　it　is　found　that　the　closer　the　2p-band　center　of　O*　is　to　the　Fermi　level,　the　stronger　the　Lewis　basicity　of　O*,　which　in　turn　facilitates　the　C–H　bond　activation　of　CH4.　This　work　provides　insights　into　the　efficient　CH4　activation　through　the　design　of　dilute　alloys　with　tunable　O*　adsorption　characteristics,　paving　the　way　for　the　development　of　efficient　catalysts　for　CH4　conversion.　©　2025　Elsevier　B.V.