Preparation and thermal treatment of Pd/Ag composite membrane on a porous alumina tube by sequential electroless plating technique for H2 separation

Pd/Ag/α-Al₂O₃ composite membranes were prepared by sequential electroless plating technique. The prepared membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spec-troscopy, and inductively coupled plasma atomic emission spectroscopy techniques (ICP-AES). Effects of annealing time, Ag content, and air treatment on the hydrogen permeation flux and morphology of the alloys were investigated. The results of the investigation showed that the prepared type of tube had a good potential as substrate for membrane preparation. In addition, a uniform defect-free alloy was prepared by annealing at 550°C in H₂ atmosphere. The permeation results showed an increase in H₂ permeation flux by increasing the Ag content and the annealing time. In addition, the air treatment of the prepared membranes at 400°C for 1 h changed the morphology of the alloy and substantially enhanced the hydrogen flux.