To　investigate　the　contribution　of　the　ZnO　supports　in　PdZn/ZnO　catalysts　used　for　methanol　steam　re-forming　(MSR),　we　have　investigated　methanol　steam　re-forming　on　two　different　ZnO　powder　samples.　The　powder　samples　included　a　commercial　powder　with　both　polar　and　nonpolar　surfaces　exposed,　and　a　plate-like　sample　preferentially　exposing　the　polar　ZnO(001)/　(001I...)　surfaces.　ZnO　was　found　to　be　active　and　selective　for　MSR,　with　the　polar　surfaces　being　most　active,　but　the　activation　energy　for　reaction　(∼100　kJ/mol)　was　much　larger　than　on　unsupported　PdZn(∼50　kJ/mol)　or　PdZn/ZnO.　The　experimental　findings　are　supported　by　DFT　calculations　on　key　elementary　steps　and　reaction　intermediates　on　the　ZnO(001)　surface.　We　conclude　that　the　contribution　of　the　ZnO　support　to　the　MSR　activity　PdZn/ZnO　catalyst　system　may　not　be　very　significant.　©　2013　American　Chemical　Society.