Methanol　decomposition　on　noble　metal　surfaces　is　an　important　industrial　process　and　prototype　for　understanding　heterogeneous　catalysis.　Despite　many　advances,　the　role　played　by　surface　defects　and　structural　sensitivity　is　still　not　fully　understood.　In　this　work,　methanol　decomposition　on　a　stepped　palladium　surface,　Pd(211),　is　investigated　using　periodic　density　functional　theory　(DFT).　The　activation　barriers　and　thermochemistry　for　relevant　elementary　steps　leading　to　the　final　decomposition　products　CO　and　H　2　are　obtained.　Similar　to　the　previous　theoretical　results　on　flat　Pd　surfaces,　the　initial　C-H　bond　scission　is　preferred　on　Pd(211)　because　it　has　a　lower　barrier　than　those　for　the　initial　O-H　and　C-O　scissions.　It　was　also　found　that　the　barriers　for　the　C-H　or　O-H　bond　scissions　are　lowered　at　the　step　sites.　Finally,　kinetic　Monte　Carlo　simulations　on　a　realistic　Pd　surface　reproduce　the　temperature-programmed　desorption　spectrum　for　methanol　decomposition　but　only　when　modified　DFT　data　are　used.　These　simulations　show　that　most　of　the　reaction　occurs　at　under-coordinated　sites.　©　2012　American　Chemical　Society.