Preparation of Pd Composite Membrane and Their Properties Measurement

The preparation of Pd composite membrane (Pd-CM) by impregnation or electroless platingwajs studied. The permeaselectivity to hydrogen and the catalytic activity for the dehydrogenationof methanol to methyl formate (MeF) of u Pd/SiO2/ceramic membranes were measured. Theresults show that the quajity of u SiO2/ceramic substrate membrane has an influence on theproperties of pd/SiO2/ceramic .In the process of preparing Pd-CM, the growing mechanism ofPd surface membrane in impregnation method is different with that in electroless plating method.When the same SiO2/ceramic is used as a substrate membrane, the Pd-CM prepared byelectroless planting has a good behavior than by impregnation. Hydrogen in mixture gases ofN2/H2 or H2/CH3OH, can be separated completely with the Pd-CM prepared by impregnation at150C. For the topic reaction at 100℃, the higher conversion of methanol and lower selectivityto product MeF can be obtained in the Pd-CM reactor prepared by electroless plating than thatby impregnation. The Pd-CM was also characterized by SEM, XRD and the structure differencebetween two Pd-CMs prepared with different methods was discussed.