In situ XPS study of methanol reforming on PdGa near-surface intermetallic phases

► A Pd1Ga1 surface without Ga2O3 contact is inactive for CO2 formation in methanol steam reforming. ► In situ XPS spectroscopy showed that water activation is blocked on Pd1Ga1. ► The valence band electronic structure of Pd1Ga1 favors selective dehydrogenation to H2CO. ► In oxidative steam reforming, the Pd1Ga1 surface behaves like extended Pd. ► Thus, total methanol oxidation by O2 at low temperatures is predominant.