Partial oxidation of methanol over supported palladium catalysts

Hydrogen production by partial oxidation of methanol (CH3OH+1/2 O-2 reversible arrow 2 H-2+CO2) was studied over ZnO- and ZrO2-supported Pd catalysts. Catalyst performance was investigated under feed ratios O-2/CH3OH (molar) of 0.3 and 0.5 at 503-543 K. irrespective of the large difference in BET area of Pd/ZnO and Pd/ZrO2 catalysts, significant differences were observed when comparing H-2 selectivities. For the 1% Pd/ZnO catalyst, reaction occurs through consecutive oxidation --> reforming steps. However, the behavior of catalyst 1% Pd/ZrO2 approached that expected for Group 8 metals, that is, although the oxidation products are observed as for the catalyst 1% Pd/ZnO, the decomposition reaction seems to occur to a greater extent. Catalyst characterization by TPR, X-ray diffraction and XPS revealed that PdZn alloys can be formed upon reduction of Pd/ZnO catalysts at moderate temperatures. (C) 1998 Elsevier Science B.V.