Deposition of palladium inside straight mesopores of anodic alumina tube and its hydrogen permeability

A new method of preparing a composite type of palladium membrane for hydrog en separation, viz. a combined sputtering and electroplating technique, was elaborated, and its hydrogen permeability and selectivity were measured in the range 200 350 degrees C. As a support, an anodic aluminum oxide tube, was used with uniform straight pores of several tens of nanometers in diame ter, inside which palladium deposition was tried by means of electroplating . The principal conditions of the electroplating, such as the current densi ty and time, were examined to obtain a composite membrane tube with as few defects as possible. Under optimum electroplating conditions, it was observ ed with SEM and FE-SEM that a thin layer of palladium formed with a thickne ss of several micrometers was densely packed inside the pores. The ideal se paration factor for hydrogen and nitrogen was found to be more than 1000, a bove 300 degrees C. (C) 2000 Elsevier Science B.V. All lights reserved.