Metallic Pt as active sites for the water-gas shift reaction on alkali-promoted supported catalysts

► The WGS rate is promoted by the addition of alkali (Na > Li ∼ K) on Pt/Al2O3 and Pt/TiO2. ► In situ XANES suggests that metallic Pt with alkali oxides nearby is the active site. ► On alumina or titania, the alkali addition results in distinctive changes in the WGS kinetics.